LCOV - code coverage report
Current view: top level - fs/btrfs - free-space-cache.c (source / functions) Hit Total Coverage
Test: fstests of 6.5.0-rc4-xfsx @ Mon Jul 31 20:08:34 PDT 2023 Lines: 1742 2077 83.9 %
Date: 2023-07-31 20:08:34 Functions: 80 87 92.0 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  * Copyright (C) 2008 Red Hat.  All rights reserved.
       4             :  */
       5             : 
       6             : #include <linux/pagemap.h>
       7             : #include <linux/sched.h>
       8             : #include <linux/sched/signal.h>
       9             : #include <linux/slab.h>
      10             : #include <linux/math64.h>
      11             : #include <linux/ratelimit.h>
      12             : #include <linux/error-injection.h>
      13             : #include <linux/sched/mm.h>
      14             : #include "ctree.h"
      15             : #include "fs.h"
      16             : #include "messages.h"
      17             : #include "misc.h"
      18             : #include "free-space-cache.h"
      19             : #include "transaction.h"
      20             : #include "disk-io.h"
      21             : #include "extent_io.h"
      22             : #include "volumes.h"
      23             : #include "space-info.h"
      24             : #include "delalloc-space.h"
      25             : #include "block-group.h"
      26             : #include "discard.h"
      27             : #include "subpage.h"
      28             : #include "inode-item.h"
      29             : #include "accessors.h"
      30             : #include "file-item.h"
      31             : #include "file.h"
      32             : #include "super.h"
      33             : 
      34             : #define BITS_PER_BITMAP         (PAGE_SIZE * 8UL)
      35             : #define MAX_CACHE_BYTES_PER_GIG SZ_64K
      36             : #define FORCE_EXTENT_THRESHOLD  SZ_1M
      37             : 
      38             : static struct kmem_cache *btrfs_free_space_cachep;
      39             : static struct kmem_cache *btrfs_free_space_bitmap_cachep;
      40             : 
      41             : struct btrfs_trim_range {
      42             :         u64 start;
      43             :         u64 bytes;
      44             :         struct list_head list;
      45             : };
      46             : 
      47             : static int link_free_space(struct btrfs_free_space_ctl *ctl,
      48             :                            struct btrfs_free_space *info);
      49             : static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
      50             :                               struct btrfs_free_space *info, bool update_stat);
      51             : static int search_bitmap(struct btrfs_free_space_ctl *ctl,
      52             :                          struct btrfs_free_space *bitmap_info, u64 *offset,
      53             :                          u64 *bytes, bool for_alloc);
      54             : static void free_bitmap(struct btrfs_free_space_ctl *ctl,
      55             :                         struct btrfs_free_space *bitmap_info);
      56             : static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
      57             :                               struct btrfs_free_space *info, u64 offset,
      58             :                               u64 bytes, bool update_stats);
      59             : 
      60       30743 : static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
      61             : {
      62       30743 :         struct btrfs_free_space *info;
      63       30743 :         struct rb_node *node;
      64             : 
      65      158569 :         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
      66      127826 :                 info = rb_entry(node, struct btrfs_free_space, offset_index);
      67      127826 :                 if (!info->bitmap) {
      68      127562 :                         unlink_free_space(ctl, info, true);
      69      127562 :                         kmem_cache_free(btrfs_free_space_cachep, info);
      70             :                 } else {
      71         264 :                         free_bitmap(ctl, info);
      72             :                 }
      73             : 
      74      127826 :                 cond_resched_lock(&ctl->tree_lock);
      75             :         }
      76       30743 : }
      77             : 
      78        1074 : static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
      79             :                                                struct btrfs_path *path,
      80             :                                                u64 offset)
      81             : {
      82        1074 :         struct btrfs_fs_info *fs_info = root->fs_info;
      83        1074 :         struct btrfs_key key;
      84        1074 :         struct btrfs_key location;
      85        1074 :         struct btrfs_disk_key disk_key;
      86        1074 :         struct btrfs_free_space_header *header;
      87        1074 :         struct extent_buffer *leaf;
      88        1074 :         struct inode *inode = NULL;
      89        1074 :         unsigned nofs_flag;
      90        1074 :         int ret;
      91             : 
      92        1074 :         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
      93        1074 :         key.offset = offset;
      94        1074 :         key.type = 0;
      95             : 
      96        1074 :         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
      97        1074 :         if (ret < 0)
      98           0 :                 return ERR_PTR(ret);
      99        1074 :         if (ret > 0) {
     100        1066 :                 btrfs_release_path(path);
     101        1066 :                 return ERR_PTR(-ENOENT);
     102             :         }
     103             : 
     104           8 :         leaf = path->nodes[0];
     105           8 :         header = btrfs_item_ptr(leaf, path->slots[0],
     106             :                                 struct btrfs_free_space_header);
     107           8 :         btrfs_free_space_key(leaf, header, &disk_key);
     108           8 :         btrfs_disk_key_to_cpu(&location, &disk_key);
     109           8 :         btrfs_release_path(path);
     110             : 
     111             :         /*
     112             :          * We are often under a trans handle at this point, so we need to make
     113             :          * sure NOFS is set to keep us from deadlocking.
     114             :          */
     115           8 :         nofs_flag = memalloc_nofs_save();
     116           8 :         inode = btrfs_iget_path(fs_info->sb, location.objectid, root, path);
     117           8 :         btrfs_release_path(path);
     118           8 :         memalloc_nofs_restore(nofs_flag);
     119           8 :         if (IS_ERR(inode))
     120             :                 return inode;
     121             : 
     122           8 :         mapping_set_gfp_mask(inode->i_mapping,
     123             :                         mapping_gfp_constraint(inode->i_mapping,
     124             :                         ~(__GFP_FS | __GFP_HIGHMEM)));
     125             : 
     126           8 :         return inode;
     127             : }
     128             : 
     129        1151 : struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
     130             :                 struct btrfs_path *path)
     131             : {
     132        1151 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
     133        1151 :         struct inode *inode = NULL;
     134        1151 :         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
     135             : 
     136        1151 :         spin_lock(&block_group->lock);
     137        1151 :         if (block_group->inode)
     138          77 :                 inode = igrab(block_group->inode);
     139        1151 :         spin_unlock(&block_group->lock);
     140        1151 :         if (inode)
     141             :                 return inode;
     142             : 
     143        1074 :         inode = __lookup_free_space_inode(fs_info->tree_root, path,
     144             :                                           block_group->start);
     145        1074 :         if (IS_ERR(inode))
     146             :                 return inode;
     147             : 
     148           8 :         spin_lock(&block_group->lock);
     149           8 :         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
     150           0 :                 btrfs_info(fs_info, "Old style space inode found, converting.");
     151           0 :                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
     152             :                         BTRFS_INODE_NODATACOW;
     153           0 :                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
     154             :         }
     155             : 
     156           8 :         if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags))
     157           8 :                 block_group->inode = igrab(inode);
     158           8 :         spin_unlock(&block_group->lock);
     159             : 
     160           8 :         return inode;
     161             : }
     162             : 
     163           5 : static int __create_free_space_inode(struct btrfs_root *root,
     164             :                                      struct btrfs_trans_handle *trans,
     165             :                                      struct btrfs_path *path,
     166             :                                      u64 ino, u64 offset)
     167             : {
     168           5 :         struct btrfs_key key;
     169           5 :         struct btrfs_disk_key disk_key;
     170           5 :         struct btrfs_free_space_header *header;
     171           5 :         struct btrfs_inode_item *inode_item;
     172           5 :         struct extent_buffer *leaf;
     173             :         /* We inline CRCs for the free disk space cache */
     174           5 :         const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
     175             :                           BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
     176           5 :         int ret;
     177             : 
     178           5 :         ret = btrfs_insert_empty_inode(trans, root, path, ino);
     179           5 :         if (ret)
     180             :                 return ret;
     181             : 
     182           5 :         leaf = path->nodes[0];
     183           5 :         inode_item = btrfs_item_ptr(leaf, path->slots[0],
     184             :                                     struct btrfs_inode_item);
     185           5 :         btrfs_item_key(leaf, &disk_key, path->slots[0]);
     186           5 :         memzero_extent_buffer(leaf, (unsigned long)inode_item,
     187             :                              sizeof(*inode_item));
     188           5 :         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
     189           5 :         btrfs_set_inode_size(leaf, inode_item, 0);
     190           5 :         btrfs_set_inode_nbytes(leaf, inode_item, 0);
     191           5 :         btrfs_set_inode_uid(leaf, inode_item, 0);
     192           5 :         btrfs_set_inode_gid(leaf, inode_item, 0);
     193           5 :         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
     194           5 :         btrfs_set_inode_flags(leaf, inode_item, flags);
     195           5 :         btrfs_set_inode_nlink(leaf, inode_item, 1);
     196           5 :         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
     197           5 :         btrfs_set_inode_block_group(leaf, inode_item, offset);
     198           5 :         btrfs_mark_buffer_dirty(leaf);
     199           5 :         btrfs_release_path(path);
     200             : 
     201           5 :         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
     202           5 :         key.offset = offset;
     203           5 :         key.type = 0;
     204           5 :         ret = btrfs_insert_empty_item(trans, root, path, &key,
     205             :                                       sizeof(struct btrfs_free_space_header));
     206           5 :         if (ret < 0) {
     207           0 :                 btrfs_release_path(path);
     208           0 :                 return ret;
     209             :         }
     210             : 
     211           5 :         leaf = path->nodes[0];
     212           5 :         header = btrfs_item_ptr(leaf, path->slots[0],
     213             :                                 struct btrfs_free_space_header);
     214           5 :         memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
     215           5 :         btrfs_set_free_space_key(leaf, header, &disk_key);
     216           5 :         btrfs_mark_buffer_dirty(leaf);
     217           5 :         btrfs_release_path(path);
     218             : 
     219           5 :         return 0;
     220             : }
     221             : 
     222           5 : int create_free_space_inode(struct btrfs_trans_handle *trans,
     223             :                             struct btrfs_block_group *block_group,
     224             :                             struct btrfs_path *path)
     225             : {
     226           5 :         int ret;
     227           5 :         u64 ino;
     228             : 
     229           5 :         ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino);
     230           5 :         if (ret < 0)
     231             :                 return ret;
     232             : 
     233           5 :         return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
     234             :                                          ino, block_group->start);
     235             : }
     236             : 
     237             : /*
     238             :  * inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
     239             :  * handles lookup, otherwise it takes ownership and iputs the inode.
     240             :  * Don't reuse an inode pointer after passing it into this function.
     241             :  */
     242         539 : int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
     243             :                                   struct inode *inode,
     244             :                                   struct btrfs_block_group *block_group)
     245             : {
     246         539 :         struct btrfs_path *path;
     247         539 :         struct btrfs_key key;
     248         539 :         int ret = 0;
     249             : 
     250         539 :         path = btrfs_alloc_path();
     251         539 :         if (!path)
     252             :                 return -ENOMEM;
     253             : 
     254         539 :         if (!inode)
     255           6 :                 inode = lookup_free_space_inode(block_group, path);
     256         539 :         if (IS_ERR(inode)) {
     257         537 :                 if (PTR_ERR(inode) != -ENOENT)
     258           0 :                         ret = PTR_ERR(inode);
     259         537 :                 goto out;
     260             :         }
     261           2 :         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
     262           2 :         if (ret) {
     263           0 :                 btrfs_add_delayed_iput(BTRFS_I(inode));
     264           0 :                 goto out;
     265             :         }
     266           2 :         clear_nlink(inode);
     267             :         /* One for the block groups ref */
     268           2 :         spin_lock(&block_group->lock);
     269           2 :         if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) {
     270           2 :                 block_group->inode = NULL;
     271           2 :                 spin_unlock(&block_group->lock);
     272           2 :                 iput(inode);
     273             :         } else {
     274           0 :                 spin_unlock(&block_group->lock);
     275             :         }
     276             :         /* One for the lookup ref */
     277           2 :         btrfs_add_delayed_iput(BTRFS_I(inode));
     278             : 
     279           2 :         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
     280           2 :         key.type = 0;
     281           2 :         key.offset = block_group->start;
     282           2 :         ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path,
     283             :                                 -1, 1);
     284           2 :         if (ret) {
     285           0 :                 if (ret > 0)
     286             :                         ret = 0;
     287           0 :                 goto out;
     288             :         }
     289           2 :         ret = btrfs_del_item(trans, trans->fs_info->tree_root, path);
     290         539 : out:
     291         539 :         btrfs_free_path(path);
     292         539 :         return ret;
     293             : }
     294             : 
     295          12 : int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
     296             :                                     struct btrfs_block_group *block_group,
     297             :                                     struct inode *vfs_inode)
     298             : {
     299          12 :         struct btrfs_truncate_control control = {
     300             :                 .inode = BTRFS_I(vfs_inode),
     301             :                 .new_size = 0,
     302             :                 .ino = btrfs_ino(BTRFS_I(vfs_inode)),
     303             :                 .min_type = BTRFS_EXTENT_DATA_KEY,
     304             :                 .clear_extent_range = true,
     305             :         };
     306             :         struct btrfs_inode *inode = BTRFS_I(vfs_inode);
     307          12 :         struct btrfs_root *root = inode->root;
     308          12 :         struct extent_state *cached_state = NULL;
     309          12 :         int ret = 0;
     310          12 :         bool locked = false;
     311             : 
     312          12 :         if (block_group) {
     313           0 :                 struct btrfs_path *path = btrfs_alloc_path();
     314             : 
     315           0 :                 if (!path) {
     316           0 :                         ret = -ENOMEM;
     317           0 :                         goto fail;
     318             :                 }
     319           0 :                 locked = true;
     320           0 :                 mutex_lock(&trans->transaction->cache_write_mutex);
     321           0 :                 if (!list_empty(&block_group->io_list)) {
     322           0 :                         list_del_init(&block_group->io_list);
     323             : 
     324           0 :                         btrfs_wait_cache_io(trans, block_group, path);
     325           0 :                         btrfs_put_block_group(block_group);
     326             :                 }
     327             : 
     328             :                 /*
     329             :                  * now that we've truncated the cache away, its no longer
     330             :                  * setup or written
     331             :                  */
     332           0 :                 spin_lock(&block_group->lock);
     333           0 :                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
     334           0 :                 spin_unlock(&block_group->lock);
     335           0 :                 btrfs_free_path(path);
     336             :         }
     337             : 
     338          12 :         btrfs_i_size_write(inode, 0);
     339          12 :         truncate_pagecache(vfs_inode, 0);
     340             : 
     341          12 :         lock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
     342          12 :         btrfs_drop_extent_map_range(inode, 0, (u64)-1, false);
     343             : 
     344             :         /*
     345             :          * We skip the throttling logic for free space cache inodes, so we don't
     346             :          * need to check for -EAGAIN.
     347             :          */
     348          12 :         ret = btrfs_truncate_inode_items(trans, root, &control);
     349             : 
     350          12 :         inode_sub_bytes(&inode->vfs_inode, control.sub_bytes);
     351          12 :         btrfs_inode_safe_disk_i_size_write(inode, control.last_size);
     352             : 
     353          12 :         unlock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
     354          12 :         if (ret)
     355           0 :                 goto fail;
     356             : 
     357          12 :         ret = btrfs_update_inode(trans, root, inode);
     358             : 
     359          12 : fail:
     360          12 :         if (locked)
     361           0 :                 mutex_unlock(&trans->transaction->cache_write_mutex);
     362          12 :         if (ret)
     363           0 :                 btrfs_abort_transaction(trans, ret);
     364             : 
     365          12 :         return ret;
     366             : }
     367             : 
     368           1 : static void readahead_cache(struct inode *inode)
     369             : {
     370           1 :         struct file_ra_state ra;
     371           1 :         unsigned long last_index;
     372             : 
     373           1 :         file_ra_state_init(&ra, inode->i_mapping);
     374           1 :         last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
     375             : 
     376           1 :         page_cache_sync_readahead(inode->i_mapping, &ra, NULL, 0, last_index);
     377           1 : }
     378             : 
     379          42 : static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
     380             :                        int write)
     381             : {
     382          42 :         int num_pages;
     383             : 
     384          42 :         num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
     385             : 
     386             :         /* Make sure we can fit our crcs and generation into the first page */
     387          42 :         if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
     388             :                 return -ENOSPC;
     389             : 
     390          42 :         memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
     391             : 
     392          42 :         io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
     393          42 :         if (!io_ctl->pages)
     394             :                 return -ENOMEM;
     395             : 
     396          42 :         io_ctl->num_pages = num_pages;
     397          42 :         io_ctl->fs_info = btrfs_sb(inode->i_sb);
     398          42 :         io_ctl->inode = inode;
     399             : 
     400          42 :         return 0;
     401             : }
     402             : ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
     403             : 
     404             : static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
     405             : {
     406          42 :         kfree(io_ctl->pages);
     407          42 :         io_ctl->pages = NULL;
     408             : }
     409             : 
     410             : static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
     411             : {
     412         747 :         if (io_ctl->cur) {
     413         705 :                 io_ctl->cur = NULL;
     414         705 :                 io_ctl->orig = NULL;
     415             :         }
     416             : }
     417             : 
     418         705 : static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
     419             : {
     420         705 :         ASSERT(io_ctl->index < io_ctl->num_pages);
     421         705 :         io_ctl->page = io_ctl->pages[io_ctl->index++];
     422         705 :         io_ctl->cur = page_address(io_ctl->page);
     423         705 :         io_ctl->orig = io_ctl->cur;
     424         705 :         io_ctl->size = PAGE_SIZE;
     425         705 :         if (clear)
     426         704 :                 clear_page(io_ctl->cur);
     427         705 : }
     428             : 
     429          42 : static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
     430             : {
     431          42 :         int i;
     432             : 
     433          42 :         io_ctl_unmap_page(io_ctl);
     434             : 
     435         762 :         for (i = 0; i < io_ctl->num_pages; i++) {
     436         720 :                 if (io_ctl->pages[i]) {
     437         720 :                         btrfs_page_clear_checked(io_ctl->fs_info,
     438             :                                         io_ctl->pages[i],
     439             :                                         page_offset(io_ctl->pages[i]),
     440             :                                         PAGE_SIZE);
     441         720 :                         unlock_page(io_ctl->pages[i]);
     442         720 :                         put_page(io_ctl->pages[i]);
     443             :                 }
     444             :         }
     445          42 : }
     446             : 
     447          42 : static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
     448             : {
     449          42 :         struct page *page;
     450          42 :         struct inode *inode = io_ctl->inode;
     451          42 :         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
     452          42 :         int i;
     453             : 
     454         762 :         for (i = 0; i < io_ctl->num_pages; i++) {
     455         720 :                 int ret;
     456             : 
     457         720 :                 page = find_or_create_page(inode->i_mapping, i, mask);
     458         720 :                 if (!page) {
     459           0 :                         io_ctl_drop_pages(io_ctl);
     460           0 :                         return -ENOMEM;
     461             :                 }
     462             : 
     463         720 :                 ret = set_page_extent_mapped(page);
     464         720 :                 if (ret < 0) {
     465           0 :                         unlock_page(page);
     466           0 :                         put_page(page);
     467           0 :                         io_ctl_drop_pages(io_ctl);
     468           0 :                         return ret;
     469             :                 }
     470             : 
     471         720 :                 io_ctl->pages[i] = page;
     472         720 :                 if (uptodate && !PageUptodate(page)) {
     473           0 :                         btrfs_read_folio(NULL, page_folio(page));
     474           0 :                         lock_page(page);
     475           0 :                         if (page->mapping != inode->i_mapping) {
     476           0 :                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
     477             :                                           "free space cache page truncated");
     478           0 :                                 io_ctl_drop_pages(io_ctl);
     479           0 :                                 return -EIO;
     480             :                         }
     481           0 :                         if (!PageUptodate(page)) {
     482           0 :                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
     483             :                                            "error reading free space cache");
     484           0 :                                 io_ctl_drop_pages(io_ctl);
     485           0 :                                 return -EIO;
     486             :                         }
     487             :                 }
     488             :         }
     489             : 
     490         762 :         for (i = 0; i < io_ctl->num_pages; i++)
     491         720 :                 clear_page_dirty_for_io(io_ctl->pages[i]);
     492             : 
     493             :         return 0;
     494             : }
     495             : 
     496          41 : static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
     497             : {
     498          41 :         io_ctl_map_page(io_ctl, 1);
     499             : 
     500             :         /*
     501             :          * Skip the csum areas.  If we don't check crcs then we just have a
     502             :          * 64bit chunk at the front of the first page.
     503             :          */
     504          41 :         io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
     505          41 :         io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
     506             : 
     507          41 :         put_unaligned_le64(generation, io_ctl->cur);
     508          41 :         io_ctl->cur += sizeof(u64);
     509          41 : }
     510             : 
     511           1 : static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
     512             : {
     513           1 :         u64 cache_gen;
     514             : 
     515             :         /*
     516             :          * Skip the crc area.  If we don't check crcs then we just have a 64bit
     517             :          * chunk at the front of the first page.
     518             :          */
     519           1 :         io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
     520           1 :         io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
     521             : 
     522           1 :         cache_gen = get_unaligned_le64(io_ctl->cur);
     523           1 :         if (cache_gen != generation) {
     524           0 :                 btrfs_err_rl(io_ctl->fs_info,
     525             :                         "space cache generation (%llu) does not match inode (%llu)",
     526             :                                 cache_gen, generation);
     527           0 :                 io_ctl_unmap_page(io_ctl);
     528           0 :                 return -EIO;
     529             :         }
     530           1 :         io_ctl->cur += sizeof(u64);
     531           1 :         return 0;
     532             : }
     533             : 
     534         704 : static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
     535             : {
     536         704 :         u32 *tmp;
     537         704 :         u32 crc = ~(u32)0;
     538         704 :         unsigned offset = 0;
     539             : 
     540         704 :         if (index == 0)
     541          41 :                 offset = sizeof(u32) * io_ctl->num_pages;
     542             : 
     543         704 :         crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
     544         704 :         btrfs_crc32c_final(crc, (u8 *)&crc);
     545         704 :         io_ctl_unmap_page(io_ctl);
     546         704 :         tmp = page_address(io_ctl->pages[0]);
     547         704 :         tmp += index;
     548         704 :         *tmp = crc;
     549         704 : }
     550             : 
     551           1 : static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
     552             : {
     553           1 :         u32 *tmp, val;
     554           1 :         u32 crc = ~(u32)0;
     555           1 :         unsigned offset = 0;
     556             : 
     557           1 :         if (index == 0)
     558           1 :                 offset = sizeof(u32) * io_ctl->num_pages;
     559             : 
     560           1 :         tmp = page_address(io_ctl->pages[0]);
     561           1 :         tmp += index;
     562           1 :         val = *tmp;
     563             : 
     564           1 :         io_ctl_map_page(io_ctl, 0);
     565           1 :         crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
     566           1 :         btrfs_crc32c_final(crc, (u8 *)&crc);
     567           1 :         if (val != crc) {
     568           0 :                 btrfs_err_rl(io_ctl->fs_info,
     569             :                         "csum mismatch on free space cache");
     570           0 :                 io_ctl_unmap_page(io_ctl);
     571           0 :                 return -EIO;
     572             :         }
     573             : 
     574             :         return 0;
     575             : }
     576             : 
     577         220 : static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
     578             :                             void *bitmap)
     579             : {
     580         220 :         struct btrfs_free_space_entry *entry;
     581             : 
     582         220 :         if (!io_ctl->cur)
     583             :                 return -ENOSPC;
     584             : 
     585         220 :         entry = io_ctl->cur;
     586         220 :         put_unaligned_le64(offset, &entry->offset);
     587         220 :         put_unaligned_le64(bytes, &entry->bytes);
     588         220 :         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
     589             :                 BTRFS_FREE_SPACE_EXTENT;
     590         220 :         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
     591         220 :         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
     592             : 
     593         220 :         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
     594             :                 return 0;
     595             : 
     596           0 :         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
     597             : 
     598             :         /* No more pages to map */
     599           0 :         if (io_ctl->index >= io_ctl->num_pages)
     600             :                 return 0;
     601             : 
     602             :         /* map the next page */
     603           0 :         io_ctl_map_page(io_ctl, 1);
     604           0 :         return 0;
     605             : }
     606             : 
     607           0 : static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
     608             : {
     609           0 :         if (!io_ctl->cur)
     610             :                 return -ENOSPC;
     611             : 
     612             :         /*
     613             :          * If we aren't at the start of the current page, unmap this one and
     614             :          * map the next one if there is any left.
     615             :          */
     616           0 :         if (io_ctl->cur != io_ctl->orig) {
     617           0 :                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
     618           0 :                 if (io_ctl->index >= io_ctl->num_pages)
     619             :                         return -ENOSPC;
     620           0 :                 io_ctl_map_page(io_ctl, 0);
     621             :         }
     622             : 
     623           0 :         copy_page(io_ctl->cur, bitmap);
     624           0 :         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
     625           0 :         if (io_ctl->index < io_ctl->num_pages)
     626           0 :                 io_ctl_map_page(io_ctl, 0);
     627             :         return 0;
     628             : }
     629             : 
     630          41 : static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
     631             : {
     632             :         /*
     633             :          * If we're not on the boundary we know we've modified the page and we
     634             :          * need to crc the page.
     635             :          */
     636          41 :         if (io_ctl->cur != io_ctl->orig)
     637          41 :                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
     638             :         else
     639           0 :                 io_ctl_unmap_page(io_ctl);
     640             : 
     641         704 :         while (io_ctl->index < io_ctl->num_pages) {
     642         663 :                 io_ctl_map_page(io_ctl, 1);
     643         663 :                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
     644             :         }
     645          41 : }
     646             : 
     647           6 : static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
     648             :                             struct btrfs_free_space *entry, u8 *type)
     649             : {
     650           6 :         struct btrfs_free_space_entry *e;
     651           6 :         int ret;
     652             : 
     653           6 :         if (!io_ctl->cur) {
     654           0 :                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
     655           0 :                 if (ret)
     656             :                         return ret;
     657             :         }
     658             : 
     659           6 :         e = io_ctl->cur;
     660           6 :         entry->offset = get_unaligned_le64(&e->offset);
     661           6 :         entry->bytes = get_unaligned_le64(&e->bytes);
     662           6 :         *type = e->type;
     663           6 :         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
     664           6 :         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
     665             : 
     666           6 :         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
     667             :                 return 0;
     668             : 
     669           0 :         io_ctl_unmap_page(io_ctl);
     670             : 
     671             :         return 0;
     672             : }
     673             : 
     674           0 : static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
     675             :                               struct btrfs_free_space *entry)
     676             : {
     677           0 :         int ret;
     678             : 
     679           0 :         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
     680           0 :         if (ret)
     681             :                 return ret;
     682             : 
     683           0 :         copy_page(entry->bitmap, io_ctl->cur);
     684           0 :         io_ctl_unmap_page(io_ctl);
     685             : 
     686             :         return 0;
     687             : }
     688             : 
     689        2850 : static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
     690             : {
     691        2850 :         struct btrfs_block_group *block_group = ctl->block_group;
     692        2850 :         u64 max_bytes;
     693        2850 :         u64 bitmap_bytes;
     694        2850 :         u64 extent_bytes;
     695        2850 :         u64 size = block_group->length;
     696        2850 :         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
     697        2850 :         u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
     698             : 
     699        2850 :         max_bitmaps = max_t(u64, max_bitmaps, 1);
     700             : 
     701        2850 :         if (ctl->total_bitmaps > max_bitmaps)
     702           0 :                 btrfs_err(block_group->fs_info,
     703             : "invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu",
     704             :                           block_group->start, block_group->length,
     705             :                           ctl->total_bitmaps, ctl->unit, max_bitmaps,
     706             :                           bytes_per_bg);
     707        2850 :         ASSERT(ctl->total_bitmaps <= max_bitmaps);
     708             : 
     709             :         /*
     710             :          * We are trying to keep the total amount of memory used per 1GiB of
     711             :          * space to be MAX_CACHE_BYTES_PER_GIG.  However, with a reclamation
     712             :          * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
     713             :          * bitmaps, we may end up using more memory than this.
     714             :          */
     715        2850 :         if (size < SZ_1G)
     716             :                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
     717             :         else
     718        1132 :                 max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
     719             : 
     720        2850 :         bitmap_bytes = ctl->total_bitmaps * ctl->unit;
     721             : 
     722             :         /*
     723             :          * we want the extent entry threshold to always be at most 1/2 the max
     724             :          * bytes we can have, or whatever is less than that.
     725             :          */
     726        2850 :         extent_bytes = max_bytes - bitmap_bytes;
     727        2850 :         extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
     728             : 
     729        2850 :         ctl->extents_thresh =
     730             :                 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
     731        2850 : }
     732             : 
     733           1 : static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
     734             :                                    struct btrfs_free_space_ctl *ctl,
     735             :                                    struct btrfs_path *path, u64 offset)
     736             : {
     737           1 :         struct btrfs_fs_info *fs_info = root->fs_info;
     738           1 :         struct btrfs_free_space_header *header;
     739           1 :         struct extent_buffer *leaf;
     740           1 :         struct btrfs_io_ctl io_ctl;
     741           1 :         struct btrfs_key key;
     742           1 :         struct btrfs_free_space *e, *n;
     743           1 :         LIST_HEAD(bitmaps);
     744           1 :         u64 num_entries;
     745           1 :         u64 num_bitmaps;
     746           1 :         u64 generation;
     747           1 :         u8 type;
     748           1 :         int ret = 0;
     749             : 
     750             :         /* Nothing in the space cache, goodbye */
     751           1 :         if (!i_size_read(inode))
     752             :                 return 0;
     753             : 
     754           1 :         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
     755           1 :         key.offset = offset;
     756           1 :         key.type = 0;
     757             : 
     758           1 :         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
     759           1 :         if (ret < 0)
     760             :                 return 0;
     761           1 :         else if (ret > 0) {
     762           0 :                 btrfs_release_path(path);
     763           0 :                 return 0;
     764             :         }
     765             : 
     766           1 :         ret = -1;
     767             : 
     768           1 :         leaf = path->nodes[0];
     769           1 :         header = btrfs_item_ptr(leaf, path->slots[0],
     770             :                                 struct btrfs_free_space_header);
     771           1 :         num_entries = btrfs_free_space_entries(leaf, header);
     772           1 :         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
     773           1 :         generation = btrfs_free_space_generation(leaf, header);
     774           1 :         btrfs_release_path(path);
     775             : 
     776           1 :         if (!BTRFS_I(inode)->generation) {
     777           0 :                 btrfs_info(fs_info,
     778             :                            "the free space cache file (%llu) is invalid, skip it",
     779             :                            offset);
     780           0 :                 return 0;
     781             :         }
     782             : 
     783           1 :         if (BTRFS_I(inode)->generation != generation) {
     784           0 :                 btrfs_err(fs_info,
     785             :                           "free space inode generation (%llu) did not match free space cache generation (%llu)",
     786             :                           BTRFS_I(inode)->generation, generation);
     787           0 :                 return 0;
     788             :         }
     789             : 
     790           1 :         if (!num_entries)
     791             :                 return 0;
     792             : 
     793           1 :         ret = io_ctl_init(&io_ctl, inode, 0);
     794           1 :         if (ret)
     795             :                 return ret;
     796             : 
     797           1 :         readahead_cache(inode);
     798             : 
     799           1 :         ret = io_ctl_prepare_pages(&io_ctl, true);
     800           1 :         if (ret)
     801           0 :                 goto out;
     802             : 
     803           1 :         ret = io_ctl_check_crc(&io_ctl, 0);
     804           1 :         if (ret)
     805           0 :                 goto free_cache;
     806             : 
     807           1 :         ret = io_ctl_check_generation(&io_ctl, generation);
     808           1 :         if (ret)
     809           0 :                 goto free_cache;
     810             : 
     811           7 :         while (num_entries) {
     812           6 :                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
     813             :                                       GFP_NOFS);
     814           6 :                 if (!e) {
     815           0 :                         ret = -ENOMEM;
     816           0 :                         goto free_cache;
     817             :                 }
     818             : 
     819           6 :                 ret = io_ctl_read_entry(&io_ctl, e, &type);
     820           6 :                 if (ret) {
     821           0 :                         kmem_cache_free(btrfs_free_space_cachep, e);
     822           0 :                         goto free_cache;
     823             :                 }
     824             : 
     825           6 :                 if (!e->bytes) {
     826           0 :                         ret = -1;
     827           0 :                         kmem_cache_free(btrfs_free_space_cachep, e);
     828           0 :                         goto free_cache;
     829             :                 }
     830             : 
     831           6 :                 if (type == BTRFS_FREE_SPACE_EXTENT) {
     832           6 :                         spin_lock(&ctl->tree_lock);
     833           6 :                         ret = link_free_space(ctl, e);
     834           6 :                         spin_unlock(&ctl->tree_lock);
     835           6 :                         if (ret) {
     836           0 :                                 btrfs_err(fs_info,
     837             :                                         "Duplicate entries in free space cache, dumping");
     838           0 :                                 kmem_cache_free(btrfs_free_space_cachep, e);
     839           0 :                                 goto free_cache;
     840             :                         }
     841             :                 } else {
     842           0 :                         ASSERT(num_bitmaps);
     843           0 :                         num_bitmaps--;
     844           0 :                         e->bitmap = kmem_cache_zalloc(
     845             :                                         btrfs_free_space_bitmap_cachep, GFP_NOFS);
     846           0 :                         if (!e->bitmap) {
     847           0 :                                 ret = -ENOMEM;
     848           0 :                                 kmem_cache_free(
     849             :                                         btrfs_free_space_cachep, e);
     850           0 :                                 goto free_cache;
     851             :                         }
     852           0 :                         spin_lock(&ctl->tree_lock);
     853           0 :                         ret = link_free_space(ctl, e);
     854           0 :                         if (ret) {
     855           0 :                                 spin_unlock(&ctl->tree_lock);
     856           0 :                                 btrfs_err(fs_info,
     857             :                                         "Duplicate entries in free space cache, dumping");
     858           0 :                                 kmem_cache_free(btrfs_free_space_cachep, e);
     859           0 :                                 goto free_cache;
     860             :                         }
     861           0 :                         ctl->total_bitmaps++;
     862           0 :                         recalculate_thresholds(ctl);
     863           0 :                         spin_unlock(&ctl->tree_lock);
     864           0 :                         list_add_tail(&e->list, &bitmaps);
     865             :                 }
     866             : 
     867           6 :                 num_entries--;
     868             :         }
     869             : 
     870           1 :         io_ctl_unmap_page(&io_ctl);
     871             : 
     872             :         /*
     873             :          * We add the bitmaps at the end of the entries in order that
     874             :          * the bitmap entries are added to the cache.
     875             :          */
     876           1 :         list_for_each_entry_safe(e, n, &bitmaps, list) {
     877           0 :                 list_del_init(&e->list);
     878           0 :                 ret = io_ctl_read_bitmap(&io_ctl, e);
     879           0 :                 if (ret)
     880           0 :                         goto free_cache;
     881             :         }
     882             : 
     883           1 :         io_ctl_drop_pages(&io_ctl);
     884           1 :         ret = 1;
     885           1 : out:
     886           1 :         io_ctl_free(&io_ctl);
     887           1 :         return ret;
     888           0 : free_cache:
     889           0 :         io_ctl_drop_pages(&io_ctl);
     890             : 
     891           0 :         spin_lock(&ctl->tree_lock);
     892           0 :         __btrfs_remove_free_space_cache(ctl);
     893           0 :         spin_unlock(&ctl->tree_lock);
     894           0 :         goto out;
     895             : }
     896             : 
     897           1 : static int copy_free_space_cache(struct btrfs_block_group *block_group,
     898             :                                  struct btrfs_free_space_ctl *ctl)
     899             : {
     900           1 :         struct btrfs_free_space *info;
     901           1 :         struct rb_node *n;
     902           1 :         int ret = 0;
     903             : 
     904           7 :         while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) {
     905           6 :                 info = rb_entry(n, struct btrfs_free_space, offset_index);
     906           6 :                 if (!info->bitmap) {
     907           6 :                         const u64 offset = info->offset;
     908           6 :                         const u64 bytes = info->bytes;
     909             : 
     910           6 :                         unlink_free_space(ctl, info, true);
     911           6 :                         spin_unlock(&ctl->tree_lock);
     912           6 :                         kmem_cache_free(btrfs_free_space_cachep, info);
     913           6 :                         ret = btrfs_add_free_space(block_group, offset, bytes);
     914           6 :                         spin_lock(&ctl->tree_lock);
     915             :                 } else {
     916           0 :                         u64 offset = info->offset;
     917           0 :                         u64 bytes = ctl->unit;
     918             : 
     919           0 :                         ret = search_bitmap(ctl, info, &offset, &bytes, false);
     920           0 :                         if (ret == 0) {
     921           0 :                                 bitmap_clear_bits(ctl, info, offset, bytes, true);
     922           0 :                                 spin_unlock(&ctl->tree_lock);
     923           0 :                                 ret = btrfs_add_free_space(block_group, offset,
     924             :                                                            bytes);
     925           0 :                                 spin_lock(&ctl->tree_lock);
     926             :                         } else {
     927           0 :                                 free_bitmap(ctl, info);
     928           0 :                                 ret = 0;
     929             :                         }
     930             :                 }
     931           6 :                 cond_resched_lock(&ctl->tree_lock);
     932             :         }
     933           1 :         return ret;
     934             : }
     935             : 
     936             : static struct lock_class_key btrfs_free_space_inode_key;
     937             : 
     938          23 : int load_free_space_cache(struct btrfs_block_group *block_group)
     939             : {
     940          23 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
     941          23 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
     942          23 :         struct btrfs_free_space_ctl tmp_ctl = {};
     943          23 :         struct inode *inode;
     944          23 :         struct btrfs_path *path;
     945          23 :         int ret = 0;
     946          23 :         bool matched;
     947          23 :         u64 used = block_group->used;
     948             : 
     949             :         /*
     950             :          * Because we could potentially discard our loaded free space, we want
     951             :          * to load everything into a temporary structure first, and then if it's
     952             :          * valid copy it all into the actual free space ctl.
     953             :          */
     954          23 :         btrfs_init_free_space_ctl(block_group, &tmp_ctl);
     955             : 
     956             :         /*
     957             :          * If this block group has been marked to be cleared for one reason or
     958             :          * another then we can't trust the on disk cache, so just return.
     959             :          */
     960          23 :         spin_lock(&block_group->lock);
     961          23 :         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
     962          21 :                 spin_unlock(&block_group->lock);
     963          21 :                 return 0;
     964             :         }
     965           2 :         spin_unlock(&block_group->lock);
     966             : 
     967           2 :         path = btrfs_alloc_path();
     968           2 :         if (!path)
     969             :                 return 0;
     970           2 :         path->search_commit_root = 1;
     971           2 :         path->skip_locking = 1;
     972             : 
     973             :         /*
     974             :          * We must pass a path with search_commit_root set to btrfs_iget in
     975             :          * order to avoid a deadlock when allocating extents for the tree root.
     976             :          *
     977             :          * When we are COWing an extent buffer from the tree root, when looking
     978             :          * for a free extent, at extent-tree.c:find_free_extent(), we can find
     979             :          * block group without its free space cache loaded. When we find one
     980             :          * we must load its space cache which requires reading its free space
     981             :          * cache's inode item from the root tree. If this inode item is located
     982             :          * in the same leaf that we started COWing before, then we end up in
     983             :          * deadlock on the extent buffer (trying to read lock it when we
     984             :          * previously write locked it).
     985             :          *
     986             :          * It's safe to read the inode item using the commit root because
     987             :          * block groups, once loaded, stay in memory forever (until they are
     988             :          * removed) as well as their space caches once loaded. New block groups
     989             :          * once created get their ->cached field set to BTRFS_CACHE_FINISHED so
     990             :          * we will never try to read their inode item while the fs is mounted.
     991             :          */
     992           2 :         inode = lookup_free_space_inode(block_group, path);
     993           2 :         if (IS_ERR(inode)) {
     994           1 :                 btrfs_free_path(path);
     995           1 :                 return 0;
     996             :         }
     997             : 
     998             :         /* We may have converted the inode and made the cache invalid. */
     999           1 :         spin_lock(&block_group->lock);
    1000           1 :         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
    1001           0 :                 spin_unlock(&block_group->lock);
    1002           0 :                 btrfs_free_path(path);
    1003           0 :                 goto out;
    1004             :         }
    1005           1 :         spin_unlock(&block_group->lock);
    1006             : 
    1007             :         /*
    1008             :          * Reinitialize the class of struct inode's mapping->invalidate_lock for
    1009             :          * free space inodes to prevent false positives related to locks for normal
    1010             :          * inodes.
    1011             :          */
    1012           1 :         lockdep_set_class(&(&inode->i_data)->invalidate_lock,
    1013             :                           &btrfs_free_space_inode_key);
    1014             : 
    1015           1 :         ret = __load_free_space_cache(fs_info->tree_root, inode, &tmp_ctl,
    1016             :                                       path, block_group->start);
    1017           1 :         btrfs_free_path(path);
    1018           1 :         if (ret <= 0)
    1019           0 :                 goto out;
    1020             : 
    1021           1 :         matched = (tmp_ctl.free_space == (block_group->length - used -
    1022           1 :                                           block_group->bytes_super));
    1023             : 
    1024           1 :         if (matched) {
    1025           1 :                 spin_lock(&tmp_ctl.tree_lock);
    1026           1 :                 ret = copy_free_space_cache(block_group, &tmp_ctl);
    1027           1 :                 spin_unlock(&tmp_ctl.tree_lock);
    1028             :                 /*
    1029             :                  * ret == 1 means we successfully loaded the free space cache,
    1030             :                  * so we need to re-set it here.
    1031             :                  */
    1032           1 :                 if (ret == 0)
    1033             :                         ret = 1;
    1034             :         } else {
    1035             :                 /*
    1036             :                  * We need to call the _locked variant so we don't try to update
    1037             :                  * the discard counters.
    1038             :                  */
    1039           0 :                 spin_lock(&tmp_ctl.tree_lock);
    1040           0 :                 __btrfs_remove_free_space_cache(&tmp_ctl);
    1041           0 :                 spin_unlock(&tmp_ctl.tree_lock);
    1042           0 :                 btrfs_warn(fs_info,
    1043             :                            "block group %llu has wrong amount of free space",
    1044             :                            block_group->start);
    1045           0 :                 ret = -1;
    1046             :         }
    1047           0 : out:
    1048           0 :         if (ret < 0) {
    1049             :                 /* This cache is bogus, make sure it gets cleared */
    1050           0 :                 spin_lock(&block_group->lock);
    1051           0 :                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
    1052           0 :                 spin_unlock(&block_group->lock);
    1053           0 :                 ret = 0;
    1054             : 
    1055           0 :                 btrfs_warn(fs_info,
    1056             :                            "failed to load free space cache for block group %llu, rebuilding it now",
    1057             :                            block_group->start);
    1058             :         }
    1059             : 
    1060           1 :         spin_lock(&ctl->tree_lock);
    1061           1 :         btrfs_discard_update_discardable(block_group);
    1062           1 :         spin_unlock(&ctl->tree_lock);
    1063           1 :         iput(inode);
    1064           1 :         return ret;
    1065             : }
    1066             : 
    1067             : static noinline_for_stack
    1068          41 : int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
    1069             :                               struct btrfs_free_space_ctl *ctl,
    1070             :                               struct btrfs_block_group *block_group,
    1071             :                               int *entries, int *bitmaps,
    1072             :                               struct list_head *bitmap_list)
    1073             : {
    1074          41 :         int ret;
    1075          41 :         struct btrfs_free_cluster *cluster = NULL;
    1076          41 :         struct btrfs_free_cluster *cluster_locked = NULL;
    1077          41 :         struct rb_node *node = rb_first(&ctl->free_space_offset);
    1078          41 :         struct btrfs_trim_range *trim_entry;
    1079             : 
    1080             :         /* Get the cluster for this block_group if it exists */
    1081          41 :         if (block_group && !list_empty(&block_group->cluster_list)) {
    1082          40 :                 cluster = list_entry(block_group->cluster_list.next,
    1083             :                                      struct btrfs_free_cluster,
    1084             :                                      block_group_list);
    1085             :         }
    1086             : 
    1087          41 :         if (!node && cluster) {
    1088          14 :                 cluster_locked = cluster;
    1089          14 :                 spin_lock(&cluster_locked->lock);
    1090          14 :                 node = rb_first(&cluster->root);
    1091          14 :                 cluster = NULL;
    1092             :         }
    1093             : 
    1094             :         /* Write out the extent entries */
    1095         208 :         while (node) {
    1096         167 :                 struct btrfs_free_space *e;
    1097             : 
    1098         167 :                 e = rb_entry(node, struct btrfs_free_space, offset_index);
    1099         167 :                 *entries += 1;
    1100             : 
    1101         167 :                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
    1102         167 :                                        e->bitmap);
    1103         167 :                 if (ret)
    1104           0 :                         goto fail;
    1105             : 
    1106         167 :                 if (e->bitmap) {
    1107           0 :                         list_add_tail(&e->list, bitmap_list);
    1108           0 :                         *bitmaps += 1;
    1109             :                 }
    1110         167 :                 node = rb_next(node);
    1111         167 :                 if (!node && cluster) {
    1112          26 :                         node = rb_first(&cluster->root);
    1113          26 :                         cluster_locked = cluster;
    1114          26 :                         spin_lock(&cluster_locked->lock);
    1115          26 :                         cluster = NULL;
    1116             :                 }
    1117             :         }
    1118          41 :         if (cluster_locked) {
    1119          40 :                 spin_unlock(&cluster_locked->lock);
    1120          40 :                 cluster_locked = NULL;
    1121             :         }
    1122             : 
    1123             :         /*
    1124             :          * Make sure we don't miss any range that was removed from our rbtree
    1125             :          * because trimming is running. Otherwise after a umount+mount (or crash
    1126             :          * after committing the transaction) we would leak free space and get
    1127             :          * an inconsistent free space cache report from fsck.
    1128             :          */
    1129          41 :         list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
    1130           0 :                 ret = io_ctl_add_entry(io_ctl, trim_entry->start,
    1131             :                                        trim_entry->bytes, NULL);
    1132           0 :                 if (ret)
    1133           0 :                         goto fail;
    1134           0 :                 *entries += 1;
    1135             :         }
    1136             : 
    1137             :         return 0;
    1138           0 : fail:
    1139           0 :         if (cluster_locked)
    1140           0 :                 spin_unlock(&cluster_locked->lock);
    1141             :         return -ENOSPC;
    1142             : }
    1143             : 
    1144             : static noinline_for_stack int
    1145          41 : update_cache_item(struct btrfs_trans_handle *trans,
    1146             :                   struct btrfs_root *root,
    1147             :                   struct inode *inode,
    1148             :                   struct btrfs_path *path, u64 offset,
    1149             :                   int entries, int bitmaps)
    1150             : {
    1151          41 :         struct btrfs_key key;
    1152          41 :         struct btrfs_free_space_header *header;
    1153          41 :         struct extent_buffer *leaf;
    1154          41 :         int ret;
    1155             : 
    1156          41 :         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
    1157          41 :         key.offset = offset;
    1158          41 :         key.type = 0;
    1159             : 
    1160          41 :         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
    1161          41 :         if (ret < 0) {
    1162           0 :                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
    1163             :                                  EXTENT_DELALLOC, NULL);
    1164           0 :                 goto fail;
    1165             :         }
    1166          41 :         leaf = path->nodes[0];
    1167          41 :         if (ret > 0) {
    1168           0 :                 struct btrfs_key found_key;
    1169           0 :                 ASSERT(path->slots[0]);
    1170           0 :                 path->slots[0]--;
    1171           0 :                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
    1172           0 :                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
    1173           0 :                     found_key.offset != offset) {
    1174           0 :                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
    1175           0 :                                          inode->i_size - 1, EXTENT_DELALLOC,
    1176             :                                          NULL);
    1177           0 :                         btrfs_release_path(path);
    1178           0 :                         goto fail;
    1179             :                 }
    1180             :         }
    1181             : 
    1182          41 :         BTRFS_I(inode)->generation = trans->transid;
    1183          41 :         header = btrfs_item_ptr(leaf, path->slots[0],
    1184             :                                 struct btrfs_free_space_header);
    1185          41 :         btrfs_set_free_space_entries(leaf, header, entries);
    1186          41 :         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
    1187          41 :         btrfs_set_free_space_generation(leaf, header, trans->transid);
    1188          41 :         btrfs_mark_buffer_dirty(leaf);
    1189          41 :         btrfs_release_path(path);
    1190             : 
    1191          41 :         return 0;
    1192             : 
    1193             : fail:
    1194             :         return -1;
    1195             : }
    1196             : 
    1197          41 : static noinline_for_stack int write_pinned_extent_entries(
    1198             :                             struct btrfs_trans_handle *trans,
    1199             :                             struct btrfs_block_group *block_group,
    1200             :                             struct btrfs_io_ctl *io_ctl,
    1201             :                             int *entries)
    1202             : {
    1203          41 :         u64 start, extent_start, extent_end, len;
    1204          41 :         struct extent_io_tree *unpin = NULL;
    1205          41 :         int ret;
    1206             : 
    1207          41 :         if (!block_group)
    1208             :                 return 0;
    1209             : 
    1210             :         /*
    1211             :          * We want to add any pinned extents to our free space cache
    1212             :          * so we don't leak the space
    1213             :          *
    1214             :          * We shouldn't have switched the pinned extents yet so this is the
    1215             :          * right one
    1216             :          */
    1217          41 :         unpin = &trans->transaction->pinned_extents;
    1218             : 
    1219          41 :         start = block_group->start;
    1220             : 
    1221          94 :         while (start < block_group->start + block_group->length) {
    1222          94 :                 ret = find_first_extent_bit(unpin, start,
    1223             :                                             &extent_start, &extent_end,
    1224             :                                             EXTENT_DIRTY, NULL);
    1225          94 :                 if (ret)
    1226             :                         return 0;
    1227             : 
    1228             :                 /* This pinned extent is out of our range */
    1229          53 :                 if (extent_start >= block_group->start + block_group->length)
    1230             :                         return 0;
    1231             : 
    1232          53 :                 extent_start = max(extent_start, start);
    1233          53 :                 extent_end = min(block_group->start + block_group->length,
    1234             :                                  extent_end + 1);
    1235          53 :                 len = extent_end - extent_start;
    1236             : 
    1237          53 :                 *entries += 1;
    1238          53 :                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
    1239          53 :                 if (ret)
    1240             :                         return -ENOSPC;
    1241             : 
    1242          53 :                 start = extent_end;
    1243             :         }
    1244             : 
    1245             :         return 0;
    1246             : }
    1247             : 
    1248             : static noinline_for_stack int
    1249          41 : write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
    1250             : {
    1251          41 :         struct btrfs_free_space *entry, *next;
    1252          41 :         int ret;
    1253             : 
    1254             :         /* Write out the bitmaps */
    1255          41 :         list_for_each_entry_safe(entry, next, bitmap_list, list) {
    1256           0 :                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
    1257           0 :                 if (ret)
    1258             :                         return -ENOSPC;
    1259           0 :                 list_del_init(&entry->list);
    1260             :         }
    1261             : 
    1262             :         return 0;
    1263             : }
    1264             : 
    1265          41 : static int flush_dirty_cache(struct inode *inode)
    1266             : {
    1267          41 :         int ret;
    1268             : 
    1269          41 :         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
    1270          41 :         if (ret)
    1271           0 :                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
    1272             :                                  EXTENT_DELALLOC, NULL);
    1273             : 
    1274          41 :         return ret;
    1275             : }
    1276             : 
    1277             : static void noinline_for_stack
    1278           0 : cleanup_bitmap_list(struct list_head *bitmap_list)
    1279             : {
    1280           0 :         struct btrfs_free_space *entry, *next;
    1281             : 
    1282           0 :         list_for_each_entry_safe(entry, next, bitmap_list, list)
    1283           0 :                 list_del_init(&entry->list);
    1284           0 : }
    1285             : 
    1286             : static void noinline_for_stack
    1287           0 : cleanup_write_cache_enospc(struct inode *inode,
    1288             :                            struct btrfs_io_ctl *io_ctl,
    1289             :                            struct extent_state **cached_state)
    1290             : {
    1291           0 :         io_ctl_drop_pages(io_ctl);
    1292           0 :         unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
    1293             :                       cached_state);
    1294           0 : }
    1295             : 
    1296          41 : static int __btrfs_wait_cache_io(struct btrfs_root *root,
    1297             :                                  struct btrfs_trans_handle *trans,
    1298             :                                  struct btrfs_block_group *block_group,
    1299             :                                  struct btrfs_io_ctl *io_ctl,
    1300             :                                  struct btrfs_path *path, u64 offset)
    1301             : {
    1302          41 :         int ret;
    1303          41 :         struct inode *inode = io_ctl->inode;
    1304             : 
    1305          41 :         if (!inode)
    1306             :                 return 0;
    1307             : 
    1308             :         /* Flush the dirty pages in the cache file. */
    1309          41 :         ret = flush_dirty_cache(inode);
    1310          41 :         if (ret)
    1311           0 :                 goto out;
    1312             : 
    1313             :         /* Update the cache item to tell everyone this cache file is valid. */
    1314          41 :         ret = update_cache_item(trans, root, inode, path, offset,
    1315             :                                 io_ctl->entries, io_ctl->bitmaps);
    1316          41 : out:
    1317          41 :         if (ret) {
    1318           0 :                 invalidate_inode_pages2(inode->i_mapping);
    1319           0 :                 BTRFS_I(inode)->generation = 0;
    1320           0 :                 if (block_group)
    1321             :                         btrfs_debug(root->fs_info,
    1322             :           "failed to write free space cache for block group %llu error %d",
    1323             :                                   block_group->start, ret);
    1324             :         }
    1325          41 :         btrfs_update_inode(trans, root, BTRFS_I(inode));
    1326             : 
    1327          41 :         if (block_group) {
    1328             :                 /* the dirty list is protected by the dirty_bgs_lock */
    1329          41 :                 spin_lock(&trans->transaction->dirty_bgs_lock);
    1330             : 
    1331             :                 /* the disk_cache_state is protected by the block group lock */
    1332          41 :                 spin_lock(&block_group->lock);
    1333             : 
    1334             :                 /*
    1335             :                  * only mark this as written if we didn't get put back on
    1336             :                  * the dirty list while waiting for IO.   Otherwise our
    1337             :                  * cache state won't be right, and we won't get written again
    1338             :                  */
    1339          41 :                 if (!ret && list_empty(&block_group->dirty_list))
    1340          17 :                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
    1341          24 :                 else if (ret)
    1342           0 :                         block_group->disk_cache_state = BTRFS_DC_ERROR;
    1343             : 
    1344          41 :                 spin_unlock(&block_group->lock);
    1345          41 :                 spin_unlock(&trans->transaction->dirty_bgs_lock);
    1346          41 :                 io_ctl->inode = NULL;
    1347          41 :                 iput(inode);
    1348             :         }
    1349             : 
    1350             :         return ret;
    1351             : 
    1352             : }
    1353             : 
    1354          41 : int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
    1355             :                         struct btrfs_block_group *block_group,
    1356             :                         struct btrfs_path *path)
    1357             : {
    1358          41 :         return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
    1359             :                                      block_group, &block_group->io_ctl,
    1360             :                                      path, block_group->start);
    1361             : }
    1362             : 
    1363             : /*
    1364             :  * Write out cached info to an inode.
    1365             :  *
    1366             :  * @root:        root the inode belongs to
    1367             :  * @inode:       freespace inode we are writing out
    1368             :  * @ctl:         free space cache we are going to write out
    1369             :  * @block_group: block_group for this cache if it belongs to a block_group
    1370             :  * @io_ctl:      holds context for the io
    1371             :  * @trans:       the trans handle
    1372             :  *
    1373             :  * This function writes out a free space cache struct to disk for quick recovery
    1374             :  * on mount.  This will return 0 if it was successful in writing the cache out,
    1375             :  * or an errno if it was not.
    1376             :  */
    1377          41 : static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
    1378             :                                    struct btrfs_free_space_ctl *ctl,
    1379             :                                    struct btrfs_block_group *block_group,
    1380             :                                    struct btrfs_io_ctl *io_ctl,
    1381             :                                    struct btrfs_trans_handle *trans)
    1382             : {
    1383          41 :         struct extent_state *cached_state = NULL;
    1384          41 :         LIST_HEAD(bitmap_list);
    1385          41 :         int entries = 0;
    1386          41 :         int bitmaps = 0;
    1387          41 :         int ret;
    1388          41 :         int must_iput = 0;
    1389             : 
    1390          41 :         if (!i_size_read(inode))
    1391             :                 return -EIO;
    1392             : 
    1393          41 :         WARN_ON(io_ctl->pages);
    1394          41 :         ret = io_ctl_init(io_ctl, inode, 1);
    1395          41 :         if (ret)
    1396             :                 return ret;
    1397             : 
    1398          41 :         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
    1399           1 :                 down_write(&block_group->data_rwsem);
    1400           1 :                 spin_lock(&block_group->lock);
    1401           1 :                 if (block_group->delalloc_bytes) {
    1402           0 :                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
    1403           0 :                         spin_unlock(&block_group->lock);
    1404           0 :                         up_write(&block_group->data_rwsem);
    1405           0 :                         BTRFS_I(inode)->generation = 0;
    1406           0 :                         ret = 0;
    1407           0 :                         must_iput = 1;
    1408           0 :                         goto out;
    1409             :                 }
    1410           1 :                 spin_unlock(&block_group->lock);
    1411             :         }
    1412             : 
    1413             :         /* Lock all pages first so we can lock the extent safely. */
    1414          41 :         ret = io_ctl_prepare_pages(io_ctl, false);
    1415          41 :         if (ret)
    1416           0 :                 goto out_unlock;
    1417             : 
    1418          41 :         lock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
    1419             :                     &cached_state);
    1420             : 
    1421          41 :         io_ctl_set_generation(io_ctl, trans->transid);
    1422             : 
    1423          41 :         mutex_lock(&ctl->cache_writeout_mutex);
    1424             :         /* Write out the extent entries in the free space cache */
    1425          41 :         spin_lock(&ctl->tree_lock);
    1426          41 :         ret = write_cache_extent_entries(io_ctl, ctl,
    1427             :                                          block_group, &entries, &bitmaps,
    1428             :                                          &bitmap_list);
    1429          41 :         if (ret)
    1430           0 :                 goto out_nospc_locked;
    1431             : 
    1432             :         /*
    1433             :          * Some spaces that are freed in the current transaction are pinned,
    1434             :          * they will be added into free space cache after the transaction is
    1435             :          * committed, we shouldn't lose them.
    1436             :          *
    1437             :          * If this changes while we are working we'll get added back to
    1438             :          * the dirty list and redo it.  No locking needed
    1439             :          */
    1440          41 :         ret = write_pinned_extent_entries(trans, block_group, io_ctl, &entries);
    1441          41 :         if (ret)
    1442           0 :                 goto out_nospc_locked;
    1443             : 
    1444             :         /*
    1445             :          * At last, we write out all the bitmaps and keep cache_writeout_mutex
    1446             :          * locked while doing it because a concurrent trim can be manipulating
    1447             :          * or freeing the bitmap.
    1448             :          */
    1449          41 :         ret = write_bitmap_entries(io_ctl, &bitmap_list);
    1450          41 :         spin_unlock(&ctl->tree_lock);
    1451          41 :         mutex_unlock(&ctl->cache_writeout_mutex);
    1452          41 :         if (ret)
    1453           0 :                 goto out_nospc;
    1454             : 
    1455             :         /* Zero out the rest of the pages just to make sure */
    1456          41 :         io_ctl_zero_remaining_pages(io_ctl);
    1457             : 
    1458             :         /* Everything is written out, now we dirty the pages in the file. */
    1459          41 :         ret = btrfs_dirty_pages(BTRFS_I(inode), io_ctl->pages,
    1460          41 :                                 io_ctl->num_pages, 0, i_size_read(inode),
    1461             :                                 &cached_state, false);
    1462          41 :         if (ret)
    1463           0 :                 goto out_nospc;
    1464             : 
    1465          41 :         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
    1466           1 :                 up_write(&block_group->data_rwsem);
    1467             :         /*
    1468             :          * Release the pages and unlock the extent, we will flush
    1469             :          * them out later
    1470             :          */
    1471          41 :         io_ctl_drop_pages(io_ctl);
    1472          41 :         io_ctl_free(io_ctl);
    1473             : 
    1474          41 :         unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
    1475             :                       &cached_state);
    1476             : 
    1477             :         /*
    1478             :          * at this point the pages are under IO and we're happy,
    1479             :          * The caller is responsible for waiting on them and updating
    1480             :          * the cache and the inode
    1481             :          */
    1482          41 :         io_ctl->entries = entries;
    1483          41 :         io_ctl->bitmaps = bitmaps;
    1484             : 
    1485          41 :         ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
    1486          41 :         if (ret)
    1487           0 :                 goto out;
    1488             : 
    1489             :         return 0;
    1490             : 
    1491           0 : out_nospc_locked:
    1492           0 :         cleanup_bitmap_list(&bitmap_list);
    1493           0 :         spin_unlock(&ctl->tree_lock);
    1494           0 :         mutex_unlock(&ctl->cache_writeout_mutex);
    1495             : 
    1496           0 : out_nospc:
    1497           0 :         cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
    1498             : 
    1499           0 : out_unlock:
    1500           0 :         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
    1501           0 :                 up_write(&block_group->data_rwsem);
    1502             : 
    1503           0 : out:
    1504           0 :         io_ctl->inode = NULL;
    1505           0 :         io_ctl_free(io_ctl);
    1506           0 :         if (ret) {
    1507           0 :                 invalidate_inode_pages2(inode->i_mapping);
    1508           0 :                 BTRFS_I(inode)->generation = 0;
    1509             :         }
    1510           0 :         btrfs_update_inode(trans, root, BTRFS_I(inode));
    1511           0 :         if (must_iput)
    1512           0 :                 iput(inode);
    1513             :         return ret;
    1514             : }
    1515             : 
    1516          41 : int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
    1517             :                           struct btrfs_block_group *block_group,
    1518             :                           struct btrfs_path *path)
    1519             : {
    1520          41 :         struct btrfs_fs_info *fs_info = trans->fs_info;
    1521          41 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    1522          41 :         struct inode *inode;
    1523          41 :         int ret = 0;
    1524             : 
    1525          41 :         spin_lock(&block_group->lock);
    1526          41 :         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
    1527           0 :                 spin_unlock(&block_group->lock);
    1528           0 :                 return 0;
    1529             :         }
    1530          41 :         spin_unlock(&block_group->lock);
    1531             : 
    1532          41 :         inode = lookup_free_space_inode(block_group, path);
    1533          41 :         if (IS_ERR(inode))
    1534             :                 return 0;
    1535             : 
    1536          41 :         ret = __btrfs_write_out_cache(fs_info->tree_root, inode, ctl,
    1537             :                                 block_group, &block_group->io_ctl, trans);
    1538          41 :         if (ret) {
    1539           0 :                 btrfs_debug(fs_info,
    1540             :           "failed to write free space cache for block group %llu error %d",
    1541             :                           block_group->start, ret);
    1542           0 :                 spin_lock(&block_group->lock);
    1543           0 :                 block_group->disk_cache_state = BTRFS_DC_ERROR;
    1544           0 :                 spin_unlock(&block_group->lock);
    1545             : 
    1546           0 :                 block_group->io_ctl.inode = NULL;
    1547           0 :                 iput(inode);
    1548             :         }
    1549             : 
    1550             :         /*
    1551             :          * if ret == 0 the caller is expected to call btrfs_wait_cache_io
    1552             :          * to wait for IO and put the inode
    1553             :          */
    1554             : 
    1555             :         return ret;
    1556             : }
    1557             : 
    1558             : static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
    1559             :                                           u64 offset)
    1560             : {
    1561     5392554 :         ASSERT(offset >= bitmap_start);
    1562     5392554 :         offset -= bitmap_start;
    1563     5392554 :         return (unsigned long)(div_u64(offset, unit));
    1564             : }
    1565             : 
    1566             : static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
    1567             : {
    1568     4633564 :         return (unsigned long)(div_u64(bytes, unit));
    1569             : }
    1570             : 
    1571             : static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
    1572             :                                    u64 offset)
    1573             : {
    1574     4486605 :         u64 bitmap_start;
    1575     4486605 :         u64 bytes_per_bitmap;
    1576             : 
    1577     4486605 :         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
    1578     4486605 :         bitmap_start = offset - ctl->start;
    1579     4486605 :         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
    1580     4486605 :         bitmap_start *= bytes_per_bitmap;
    1581     4486605 :         bitmap_start += ctl->start;
    1582             : 
    1583     3544317 :         return bitmap_start;
    1584             : }
    1585             : 
    1586     7565592 : static int tree_insert_offset(struct btrfs_free_space_ctl *ctl,
    1587             :                               struct btrfs_free_cluster *cluster,
    1588             :                               struct btrfs_free_space *new_entry)
    1589             : {
    1590     7565592 :         struct rb_root *root;
    1591     7565592 :         struct rb_node **p;
    1592     7565592 :         struct rb_node *parent = NULL;
    1593             : 
    1594     7565592 :         lockdep_assert_held(&ctl->tree_lock);
    1595             : 
    1596     7565592 :         if (cluster) {
    1597     1227518 :                 lockdep_assert_held(&cluster->lock);
    1598     1227518 :                 root = &cluster->root;
    1599             :         } else {
    1600     6338074 :                 root = &ctl->free_space_offset;
    1601             :         }
    1602             : 
    1603     7565592 :         p = &root->rb_node;
    1604             : 
    1605    55647699 :         while (*p) {
    1606    48082107 :                 struct btrfs_free_space *info;
    1607             : 
    1608    48082107 :                 parent = *p;
    1609    48082107 :                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
    1610             : 
    1611    48082107 :                 if (new_entry->offset < info->offset) {
    1612    11270025 :                         p = &(*p)->rb_left;
    1613    36812082 :                 } else if (new_entry->offset > info->offset) {
    1614    36801298 :                         p = &(*p)->rb_right;
    1615             :                 } else {
    1616             :                         /*
    1617             :                          * we could have a bitmap entry and an extent entry
    1618             :                          * share the same offset.  If this is the case, we want
    1619             :                          * the extent entry to always be found first if we do a
    1620             :                          * linear search through the tree, since we want to have
    1621             :                          * the quickest allocation time, and allocating from an
    1622             :                          * extent is faster than allocating from a bitmap.  So
    1623             :                          * if we're inserting a bitmap and we find an entry at
    1624             :                          * this offset, we want to go right, or after this entry
    1625             :                          * logically.  If we are inserting an extent and we've
    1626             :                          * found a bitmap, we want to go left, or before
    1627             :                          * logically.
    1628             :                          */
    1629       10784 :                         if (new_entry->bitmap) {
    1630         167 :                                 if (info->bitmap) {
    1631           0 :                                         WARN_ON_ONCE(1);
    1632           0 :                                         return -EEXIST;
    1633             :                                 }
    1634         167 :                                 p = &(*p)->rb_right;
    1635             :                         } else {
    1636       10617 :                                 if (!info->bitmap) {
    1637           0 :                                         WARN_ON_ONCE(1);
    1638           0 :                                         return -EEXIST;
    1639             :                                 }
    1640       10617 :                                 p = &(*p)->rb_left;
    1641             :                         }
    1642             :                 }
    1643             :         }
    1644             : 
    1645     7565592 :         rb_link_node(&new_entry->offset_index, parent, p);
    1646     7565592 :         rb_insert_color(&new_entry->offset_index, root);
    1647             : 
    1648     7565592 :         return 0;
    1649             : }
    1650             : 
    1651             : /*
    1652             :  * This is a little subtle.  We *only* have ->max_extent_size set if we actually
    1653             :  * searched through the bitmap and figured out the largest ->max_extent_size,
    1654             :  * otherwise it's 0.  In the case that it's 0 we don't want to tell the
    1655             :  * allocator the wrong thing, we want to use the actual real max_extent_size
    1656             :  * we've found already if it's larger, or we want to use ->bytes.
    1657             :  *
    1658             :  * This matters because find_free_space() will skip entries who's ->bytes is
    1659             :  * less than the required bytes.  So if we didn't search down this bitmap, we
    1660             :  * may pick some previous entry that has a smaller ->max_extent_size than we
    1661             :  * have.  For example, assume we have two entries, one that has
    1662             :  * ->max_extent_size set to 4K and ->bytes set to 1M.  A second entry hasn't set
    1663             :  * ->max_extent_size yet, has ->bytes set to 8K and it's contiguous.  We will
    1664             :  *  call into find_free_space(), and return with max_extent_size == 4K, because
    1665             :  *  that first bitmap entry had ->max_extent_size set, but the second one did
    1666             :  *  not.  If instead we returned 8K we'd come in searching for 8K, and find the
    1667             :  *  8K contiguous range.
    1668             :  *
    1669             :  *  Consider the other case, we have 2 8K chunks in that second entry and still
    1670             :  *  don't have ->max_extent_size set.  We'll return 16K, and the next time the
    1671             :  *  allocator comes in it'll fully search our second bitmap, and this time it'll
    1672             :  *  get an uptodate value of 8K as the maximum chunk size.  Then we'll get the
    1673             :  *  right allocation the next loop through.
    1674             :  */
    1675             : static inline u64 get_max_extent_size(const struct btrfs_free_space *entry)
    1676             : {
    1677    51714298 :         if (entry->bitmap && entry->max_extent_size)
    1678             :                 return entry->max_extent_size;
    1679    99704861 :         return entry->bytes;
    1680             : }
    1681             : 
    1682             : /*
    1683             :  * We want the largest entry to be leftmost, so this is inverted from what you'd
    1684             :  * normally expect.
    1685             :  */
    1686    49374300 : static bool entry_less(struct rb_node *node, const struct rb_node *parent)
    1687             : {
    1688    49374300 :         const struct btrfs_free_space *entry, *exist;
    1689             : 
    1690    49374300 :         entry = rb_entry(node, struct btrfs_free_space, bytes_index);
    1691    49374300 :         exist = rb_entry(parent, struct btrfs_free_space, bytes_index);
    1692    49374300 :         return get_max_extent_size(exist) < get_max_extent_size(entry);
    1693             : }
    1694             : 
    1695             : /*
    1696             :  * searches the tree for the given offset.
    1697             :  *
    1698             :  * fuzzy - If this is set, then we are trying to make an allocation, and we just
    1699             :  * want a section that has at least bytes size and comes at or after the given
    1700             :  * offset.
    1701             :  */
    1702             : static struct btrfs_free_space *
    1703    12164957 : tree_search_offset(struct btrfs_free_space_ctl *ctl,
    1704             :                    u64 offset, int bitmap_only, int fuzzy)
    1705             : {
    1706    12164957 :         struct rb_node *n = ctl->free_space_offset.rb_node;
    1707    12164957 :         struct btrfs_free_space *entry = NULL, *prev = NULL;
    1708             : 
    1709    12164957 :         lockdep_assert_held(&ctl->tree_lock);
    1710             : 
    1711             :         /* find entry that is closest to the 'offset' */
    1712   101755832 :         while (n) {
    1713    92039042 :                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
    1714    92039042 :                 prev = entry;
    1715             : 
    1716    92039042 :                 if (offset < entry->offset)
    1717    30938210 :                         n = n->rb_left;
    1718    61100832 :                 else if (offset > entry->offset)
    1719    58652665 :                         n = n->rb_right;
    1720             :                 else
    1721             :                         break;
    1722             : 
    1723             :                 entry = NULL;
    1724             :         }
    1725             : 
    1726    12164957 :         if (bitmap_only) {
    1727     2130578 :                 if (!entry)
    1728             :                         return NULL;
    1729     1941835 :                 if (entry->bitmap)
    1730             :                         return entry;
    1731             : 
    1732             :                 /*
    1733             :                  * bitmap entry and extent entry may share same offset,
    1734             :                  * in that case, bitmap entry comes after extent entry.
    1735             :                  */
    1736       64397 :                 n = rb_next(n);
    1737       64397 :                 if (!n)
    1738             :                         return NULL;
    1739       63674 :                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
    1740       63674 :                 if (entry->offset != offset)
    1741             :                         return NULL;
    1742             : 
    1743       55205 :                 WARN_ON(!entry->bitmap);
    1744             :                 return entry;
    1745    10034379 :         } else if (entry) {
    1746      506334 :                 if (entry->bitmap) {
    1747             :                         /*
    1748             :                          * if previous extent entry covers the offset,
    1749             :                          * we should return it instead of the bitmap entry
    1750             :                          */
    1751       49187 :                         n = rb_prev(&entry->offset_index);
    1752       49187 :                         if (n) {
    1753       38789 :                                 prev = rb_entry(n, struct btrfs_free_space,
    1754             :                                                 offset_index);
    1755       38789 :                                 if (!prev->bitmap &&
    1756       28795 :                                     prev->offset + prev->bytes > offset)
    1757         949 :                                         entry = prev;
    1758             :                         }
    1759             :                 }
    1760      506334 :                 return entry;
    1761             :         }
    1762             : 
    1763     9528045 :         if (!prev)
    1764             :                 return NULL;
    1765             : 
    1766             :         /* find last entry before the 'offset' */
    1767     9441097 :         entry = prev;
    1768     9441097 :         if (entry->offset > offset) {
    1769     3459805 :                 n = rb_prev(&entry->offset_index);
    1770     3459808 :                 if (n) {
    1771             :                         entry = rb_entry(n, struct btrfs_free_space,
    1772             :                                         offset_index);
    1773             :                         ASSERT(entry->offset <= offset);
    1774             :                 } else {
    1775      965413 :                         if (fuzzy)
    1776             :                                 return entry;
    1777             :                         else
    1778       14800 :                                 return NULL;
    1779             :                 }
    1780             :         }
    1781             : 
    1782     8475687 :         if (entry->bitmap) {
    1783      195968 :                 n = rb_prev(&entry->offset_index);
    1784      195968 :                 if (n) {
    1785      156407 :                         prev = rb_entry(n, struct btrfs_free_space,
    1786             :                                         offset_index);
    1787      156407 :                         if (!prev->bitmap &&
    1788      135531 :                             prev->offset + prev->bytes > offset)
    1789             :                                 return prev;
    1790             :                 }
    1791      195955 :                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
    1792             :                         return entry;
    1793     8279719 :         } else if (entry->offset + entry->bytes > offset)
    1794             :                 return entry;
    1795             : 
    1796     7754758 :         if (!fuzzy)
    1797             :                 return NULL;
    1798             : 
    1799      675337 :         while (1) {
    1800      675337 :                 n = rb_next(&entry->offset_index);
    1801      675338 :                 if (!n)
    1802             :                         return NULL;
    1803      674254 :                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
    1804      674254 :                 if (entry->bitmap) {
    1805        1037 :                         if (entry->offset + BITS_PER_BITMAP *
    1806        1037 :                             ctl->unit > offset)
    1807             :                                 break;
    1808             :                 } else {
    1809      673217 :                         if (entry->offset + entry->bytes > offset)
    1810             :                                 break;
    1811             :                 }
    1812             :         }
    1813             :         return entry;
    1814             : }
    1815             : 
    1816     5110526 : static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl,
    1817             :                                      struct btrfs_free_space *info,
    1818             :                                      bool update_stat)
    1819             : {
    1820     5110526 :         lockdep_assert_held(&ctl->tree_lock);
    1821             : 
    1822     5110526 :         rb_erase(&info->offset_index, &ctl->free_space_offset);
    1823     5110532 :         rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
    1824     5110527 :         ctl->free_extents--;
    1825             : 
    1826     5110527 :         if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
    1827     3054293 :                 ctl->discardable_extents[BTRFS_STAT_CURR]--;
    1828     3054293 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
    1829             :         }
    1830             : 
    1831     5110527 :         if (update_stat)
    1832     5109017 :                 ctl->free_space -= info->bytes;
    1833     5110527 : }
    1834             : 
    1835     6313013 : static int link_free_space(struct btrfs_free_space_ctl *ctl,
    1836             :                            struct btrfs_free_space *info)
    1837             : {
    1838     6313013 :         int ret = 0;
    1839             : 
    1840     6313013 :         lockdep_assert_held(&ctl->tree_lock);
    1841             : 
    1842     6313013 :         ASSERT(info->bytes || info->bitmap);
    1843     6313013 :         ret = tree_insert_offset(ctl, NULL, info);
    1844     6313016 :         if (ret)
    1845             :                 return ret;
    1846             : 
    1847     6313016 :         rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
    1848             : 
    1849     6313023 :         if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
    1850     4243914 :                 ctl->discardable_extents[BTRFS_STAT_CURR]++;
    1851     4243914 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
    1852             :         }
    1853             : 
    1854     6313023 :         ctl->free_space += info->bytes;
    1855     6313023 :         ctl->free_extents++;
    1856     6313023 :         return ret;
    1857             : }
    1858             : 
    1859     3229465 : static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl,
    1860             :                                 struct btrfs_free_space *info)
    1861             : {
    1862     3229465 :         ASSERT(info->bitmap);
    1863             : 
    1864             :         /*
    1865             :          * If our entry is empty it's because we're on a cluster and we don't
    1866             :          * want to re-link it into our ctl bytes index.
    1867             :          */
    1868     3229465 :         if (RB_EMPTY_NODE(&info->bytes_index))
    1869             :                 return;
    1870             : 
    1871     1624707 :         lockdep_assert_held(&ctl->tree_lock);
    1872             : 
    1873     1624707 :         rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
    1874     1624710 :         rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
    1875             : }
    1876             : 
    1877     1552818 : static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
    1878             :                                      struct btrfs_free_space *info,
    1879             :                                      u64 offset, u64 bytes, bool update_stat)
    1880             : {
    1881     1552818 :         unsigned long start, count, end;
    1882     1552818 :         int extent_delta = -1;
    1883             : 
    1884     1552818 :         start = offset_to_bit(info->offset, ctl->unit, offset);
    1885     1552818 :         count = bytes_to_bits(bytes, ctl->unit);
    1886     1552818 :         end = start + count;
    1887     1552818 :         ASSERT(end <= BITS_PER_BITMAP);
    1888             : 
    1889     1552818 :         bitmap_clear(info->bitmap, start, count);
    1890             : 
    1891     1552817 :         info->bytes -= bytes;
    1892     1552817 :         if (info->max_extent_size > ctl->unit)
    1893       38504 :                 info->max_extent_size = 0;
    1894             : 
    1895     1552817 :         relink_bitmap_entry(ctl, info);
    1896             : 
    1897     3105458 :         if (start && test_bit(start - 1, info->bitmap))
    1898         642 :                 extent_delta++;
    1899             : 
    1900     3105363 :         if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
    1901     1054040 :                 extent_delta++;
    1902             : 
    1903     1552813 :         info->bitmap_extents += extent_delta;
    1904     1552813 :         if (!btrfs_free_space_trimmed(info)) {
    1905     1540853 :                 ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
    1906     1540853 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
    1907             :         }
    1908             : 
    1909     1552813 :         if (update_stat)
    1910      419625 :                 ctl->free_space -= bytes;
    1911     1552813 : }
    1912             : 
    1913     1618558 : static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
    1914             :                             struct btrfs_free_space *info, u64 offset,
    1915             :                             u64 bytes)
    1916             : {
    1917     1618558 :         unsigned long start, count, end;
    1918     1618558 :         int extent_delta = 1;
    1919             : 
    1920     1618558 :         start = offset_to_bit(info->offset, ctl->unit, offset);
    1921     1618558 :         count = bytes_to_bits(bytes, ctl->unit);
    1922     1618558 :         end = start + count;
    1923     1618558 :         ASSERT(end <= BITS_PER_BITMAP);
    1924             : 
    1925     1618558 :         bitmap_set(info->bitmap, start, count);
    1926             : 
    1927             :         /*
    1928             :          * We set some bytes, we have no idea what the max extent size is
    1929             :          * anymore.
    1930             :          */
    1931     1618557 :         info->max_extent_size = 0;
    1932     1618557 :         info->bytes += bytes;
    1933     1618557 :         ctl->free_space += bytes;
    1934             : 
    1935     1618557 :         relink_bitmap_entry(ctl, info);
    1936             : 
    1937     3236930 :         if (start && test_bit(start - 1, info->bitmap))
    1938      522799 :                 extent_delta--;
    1939             : 
    1940     3236827 :         if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
    1941      525378 :                 extent_delta--;
    1942             : 
    1943     1618558 :         info->bitmap_extents += extent_delta;
    1944     1618558 :         if (!btrfs_free_space_trimmed(info)) {
    1945     1589854 :                 ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
    1946     1589854 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
    1947             :         }
    1948     1618558 : }
    1949             : 
    1950             : /*
    1951             :  * If we can not find suitable extent, we will use bytes to record
    1952             :  * the size of the max extent.
    1953             :  */
    1954     1947135 : static int search_bitmap(struct btrfs_free_space_ctl *ctl,
    1955             :                          struct btrfs_free_space *bitmap_info, u64 *offset,
    1956             :                          u64 *bytes, bool for_alloc)
    1957             : {
    1958     1947135 :         unsigned long found_bits = 0;
    1959     1947135 :         unsigned long max_bits = 0;
    1960     1947135 :         unsigned long bits, i;
    1961     1947135 :         unsigned long next_zero;
    1962     1947135 :         unsigned long extent_bits;
    1963             : 
    1964             :         /*
    1965             :          * Skip searching the bitmap if we don't have a contiguous section that
    1966             :          * is large enough for this allocation.
    1967             :          */
    1968     1947135 :         if (for_alloc &&
    1969     1920626 :             bitmap_info->max_extent_size &&
    1970      524099 :             bitmap_info->max_extent_size < *bytes) {
    1971      485671 :                 *bytes = bitmap_info->max_extent_size;
    1972      485671 :                 return -1;
    1973             :         }
    1974             : 
    1975     1461464 :         i = offset_to_bit(bitmap_info->offset, ctl->unit,
    1976     1461464 :                           max_t(u64, *offset, bitmap_info->offset));
    1977     1461464 :         bits = bytes_to_bits(*bytes, ctl->unit);
    1978             : 
    1979    11005034 :         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
    1980    10946533 :                 if (for_alloc && bits == 1) {
    1981             :                         found_bits = 1;
    1982             :                         break;
    1983             :                 }
    1984    10803788 :                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
    1985             :                                                BITS_PER_BITMAP, i);
    1986    10804203 :                 extent_bits = next_zero - i;
    1987    10804203 :                 if (extent_bits >= bits) {
    1988             :                         found_bits = extent_bits;
    1989             :                         break;
    1990     9543570 :                 } else if (extent_bits > max_bits) {
    1991             :                         max_bits = extent_bits;
    1992             :                 }
    1993     9543570 :                 i = next_zero;
    1994             :         }
    1995             : 
    1996     1461471 :         if (found_bits) {
    1997     1403378 :                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
    1998     1403378 :                 *bytes = (u64)(found_bits) * ctl->unit;
    1999     1403378 :                 return 0;
    2000             :         }
    2001             : 
    2002       58093 :         *bytes = (u64)(max_bits) * ctl->unit;
    2003       58093 :         bitmap_info->max_extent_size = *bytes;
    2004       58093 :         relink_bitmap_entry(ctl, bitmap_info);
    2005       58093 :         return -1;
    2006             : }
    2007             : 
    2008             : /* Cache the size of the max extent in bytes */
    2009             : static struct btrfs_free_space *
    2010     4442402 : find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
    2011             :                 unsigned long align, u64 *max_extent_size, bool use_bytes_index)
    2012             : {
    2013     4442402 :         struct btrfs_free_space *entry;
    2014     4442402 :         struct rb_node *node;
    2015     4442402 :         u64 tmp;
    2016     4442402 :         u64 align_off;
    2017     4442402 :         int ret;
    2018             : 
    2019     4442402 :         if (!ctl->free_space_offset.rb_node)
    2020         965 :                 goto out;
    2021     4441437 : again:
    2022     4489344 :         if (use_bytes_index) {
    2023     2815041 :                 node = rb_first_cached(&ctl->free_space_bytes);
    2024             :         } else {
    2025     1674303 :                 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset),
    2026             :                                            0, 1);
    2027     1674304 :                 if (!entry)
    2028         663 :                         goto out;
    2029     1673641 :                 node = &entry->offset_index;
    2030             :         }
    2031             : 
    2032     6456280 :         for (; node; node = rb_next(node)) {
    2033     6434776 :                 if (use_bytes_index)
    2034     3288761 :                         entry = rb_entry(node, struct btrfs_free_space,
    2035             :                                          bytes_index);
    2036             :                 else
    2037             :                         entry = rb_entry(node, struct btrfs_free_space,
    2038             :                                          offset_index);
    2039             : 
    2040             :                 /*
    2041             :                  * If we are using the bytes index then all subsequent entries
    2042             :                  * in this tree are going to be < bytes, so simply set the max
    2043             :                  * extent size and exit the loop.
    2044             :                  *
    2045             :                  * If we're using the offset index then we need to keep going
    2046             :                  * through the rest of the tree.
    2047             :                  */
    2048     6434776 :                 if (entry->bytes < *bytes) {
    2049     1725316 :                         *max_extent_size = max(get_max_extent_size(entry),
    2050             :                                                *max_extent_size);
    2051     1725316 :                         if (use_bytes_index)
    2052             :                                 break;
    2053     1474207 :                         continue;
    2054             :                 }
    2055             : 
    2056             :                 /* make sure the space returned is big enough
    2057             :                  * to match our requested alignment
    2058             :                  */
    2059     4709460 :                 if (*bytes >= align) {
    2060     4709460 :                         tmp = entry->offset - ctl->start + align - 1;
    2061     4709460 :                         tmp = div64_u64(tmp, align);
    2062     4709460 :                         tmp = tmp * align + ctl->start;
    2063     4709460 :                         align_off = tmp - entry->offset;
    2064             :                 } else {
    2065           0 :                         align_off = 0;
    2066           0 :                         tmp = entry->offset;
    2067             :                 }
    2068             : 
    2069             :                 /*
    2070             :                  * We don't break here if we're using the bytes index because we
    2071             :                  * may have another entry that has the correct alignment that is
    2072             :                  * the right size, so we don't want to miss that possibility.
    2073             :                  * At worst this adds another loop through the logic, but if we
    2074             :                  * broke here we could prematurely ENOSPC.
    2075             :                  */
    2076     4709460 :                 if (entry->bytes < *bytes + align_off) {
    2077           0 :                         *max_extent_size = max(get_max_extent_size(entry),
    2078             :                                                *max_extent_size);
    2079           0 :                         continue;
    2080             :                 }
    2081             : 
    2082     4709460 :                 if (entry->bitmap) {
    2083      787541 :                         struct rb_node *old_next = rb_next(node);
    2084      787547 :                         u64 size = *bytes;
    2085             : 
    2086      787547 :                         ret = search_bitmap(ctl, entry, &tmp, &size, true);
    2087      787551 :                         if (!ret) {
    2088      246256 :                                 *offset = tmp;
    2089      246256 :                                 *bytes = size;
    2090      246256 :                                 return entry;
    2091             :                         } else {
    2092     1082590 :                                 *max_extent_size =
    2093      541295 :                                         max(get_max_extent_size(entry),
    2094             :                                             *max_extent_size);
    2095             :                         }
    2096             : 
    2097             :                         /*
    2098             :                          * The bitmap may have gotten re-arranged in the space
    2099             :                          * index here because the max_extent_size may have been
    2100             :                          * updated.  Start from the beginning again if this
    2101             :                          * happened.
    2102             :                          */
    2103      541295 :                         if (use_bytes_index && old_next != rb_next(node))
    2104       47907 :                                 goto again;
    2105      493391 :                         continue;
    2106             :                 }
    2107             : 
    2108     3921919 :                 *offset = tmp;
    2109     3921919 :                 *bytes = entry->bytes - align_off;
    2110     3921919 :                 return entry;
    2111             :         }
    2112      272598 : out:
    2113             :         return NULL;
    2114             : }
    2115             : 
    2116        1425 : static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
    2117             :                            struct btrfs_free_space *info, u64 offset)
    2118             : {
    2119        1425 :         info->offset = offset_to_bitmap(ctl, offset);
    2120        1425 :         info->bytes = 0;
    2121        1425 :         info->bitmap_extents = 0;
    2122        1425 :         INIT_LIST_HEAD(&info->list);
    2123        1425 :         link_free_space(ctl, info);
    2124        1425 :         ctl->total_bitmaps++;
    2125        1425 :         recalculate_thresholds(ctl);
    2126        1425 : }
    2127             : 
    2128        1132 : static void free_bitmap(struct btrfs_free_space_ctl *ctl,
    2129             :                         struct btrfs_free_space *bitmap_info)
    2130             : {
    2131             :         /*
    2132             :          * Normally when this is called, the bitmap is completely empty. However,
    2133             :          * if we are blowing up the free space cache for one reason or another
    2134             :          * via __btrfs_remove_free_space_cache(), then it may not be freed and
    2135             :          * we may leave stats on the table.
    2136             :          */
    2137        1132 :         if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
    2138         211 :                 ctl->discardable_extents[BTRFS_STAT_CURR] -=
    2139         211 :                         bitmap_info->bitmap_extents;
    2140         211 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
    2141             : 
    2142             :         }
    2143        1132 :         unlink_free_space(ctl, bitmap_info, true);
    2144        1132 :         kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
    2145        1132 :         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
    2146        1132 :         ctl->total_bitmaps--;
    2147        1132 :         recalculate_thresholds(ctl);
    2148        1132 : }
    2149             : 
    2150        1358 : static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
    2151             :                               struct btrfs_free_space *bitmap_info,
    2152             :                               u64 *offset, u64 *bytes)
    2153             : {
    2154        1358 :         u64 end;
    2155        1358 :         u64 search_start, search_bytes;
    2156        1358 :         int ret;
    2157             : 
    2158        1358 : again:
    2159        1358 :         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
    2160             : 
    2161             :         /*
    2162             :          * We need to search for bits in this bitmap.  We could only cover some
    2163             :          * of the extent in this bitmap thanks to how we add space, so we need
    2164             :          * to search for as much as it as we can and clear that amount, and then
    2165             :          * go searching for the next bit.
    2166             :          */
    2167        1358 :         search_start = *offset;
    2168        1358 :         search_bytes = ctl->unit;
    2169        1358 :         search_bytes = min(search_bytes, end - search_start + 1);
    2170        1358 :         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
    2171             :                             false);
    2172        1358 :         if (ret < 0 || search_start != *offset)
    2173             :                 return -EINVAL;
    2174             : 
    2175             :         /* We may have found more bits than what we need */
    2176        1358 :         search_bytes = min(search_bytes, *bytes);
    2177             : 
    2178             :         /* Cannot clear past the end of the bitmap */
    2179        1358 :         search_bytes = min(search_bytes, end - search_start + 1);
    2180             : 
    2181        1358 :         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes, true);
    2182        1358 :         *offset += search_bytes;
    2183        1358 :         *bytes -= search_bytes;
    2184             : 
    2185        1358 :         if (*bytes) {
    2186           0 :                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
    2187           0 :                 if (!bitmap_info->bytes)
    2188           0 :                         free_bitmap(ctl, bitmap_info);
    2189             : 
    2190             :                 /*
    2191             :                  * no entry after this bitmap, but we still have bytes to
    2192             :                  * remove, so something has gone wrong.
    2193             :                  */
    2194           0 :                 if (!next)
    2195             :                         return -EINVAL;
    2196             : 
    2197           0 :                 bitmap_info = rb_entry(next, struct btrfs_free_space,
    2198             :                                        offset_index);
    2199             : 
    2200             :                 /*
    2201             :                  * if the next entry isn't a bitmap we need to return to let the
    2202             :                  * extent stuff do its work.
    2203             :                  */
    2204           0 :                 if (!bitmap_info->bitmap)
    2205             :                         return -EAGAIN;
    2206             : 
    2207             :                 /*
    2208             :                  * Ok the next item is a bitmap, but it may not actually hold
    2209             :                  * the information for the rest of this free space stuff, so
    2210             :                  * look for it, and if we don't find it return so we can try
    2211             :                  * everything over again.
    2212             :                  */
    2213           0 :                 search_start = *offset;
    2214           0 :                 search_bytes = ctl->unit;
    2215           0 :                 ret = search_bitmap(ctl, bitmap_info, &search_start,
    2216             :                                     &search_bytes, false);
    2217           0 :                 if (ret < 0 || search_start != *offset)
    2218             :                         return -EAGAIN;
    2219             : 
    2220           0 :                 goto again;
    2221        1358 :         } else if (!bitmap_info->bytes)
    2222          12 :                 free_bitmap(ctl, bitmap_info);
    2223             : 
    2224             :         return 0;
    2225             : }
    2226             : 
    2227     1618558 : static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
    2228             :                                struct btrfs_free_space *info, u64 offset,
    2229             :                                u64 bytes, enum btrfs_trim_state trim_state)
    2230             : {
    2231     1618558 :         u64 bytes_to_set = 0;
    2232     1618558 :         u64 end;
    2233             : 
    2234             :         /*
    2235             :          * This is a tradeoff to make bitmap trim state minimal.  We mark the
    2236             :          * whole bitmap untrimmed if at any point we add untrimmed regions.
    2237             :          */
    2238     1618558 :         if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
    2239     1567303 :                 if (btrfs_free_space_trimmed(info)) {
    2240        1363 :                         ctl->discardable_extents[BTRFS_STAT_CURR] +=
    2241        1363 :                                 info->bitmap_extents;
    2242        1363 :                         ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
    2243             :                 }
    2244     1567303 :                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    2245             :         }
    2246             : 
    2247     1618558 :         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
    2248             : 
    2249     1618558 :         bytes_to_set = min(end - offset, bytes);
    2250             : 
    2251     1618558 :         bitmap_set_bits(ctl, info, offset, bytes_to_set);
    2252             : 
    2253     1618558 :         return bytes_to_set;
    2254             : 
    2255             : }
    2256             : 
    2257     3436183 : static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
    2258             :                       struct btrfs_free_space *info)
    2259             : {
    2260     3436183 :         struct btrfs_block_group *block_group = ctl->block_group;
    2261     3436183 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
    2262     3436183 :         bool forced = false;
    2263             : 
    2264             : #ifdef CONFIG_BTRFS_DEBUG
    2265             :         if (btrfs_should_fragment_free_space(block_group))
    2266             :                 forced = true;
    2267             : #endif
    2268             : 
    2269             :         /* This is a way to reclaim large regions from the bitmaps. */
    2270     3436183 :         if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
    2271             :                 return false;
    2272             : 
    2273             :         /*
    2274             :          * If we are below the extents threshold then we can add this as an
    2275             :          * extent, and don't have to deal with the bitmap
    2276             :          */
    2277     3381346 :         if (!forced && ctl->free_extents < ctl->extents_thresh) {
    2278             :                 /*
    2279             :                  * If this block group has some small extents we don't want to
    2280             :                  * use up all of our free slots in the cache with them, we want
    2281             :                  * to reserve them to larger extents, however if we have plenty
    2282             :                  * of cache left then go ahead an dadd them, no sense in adding
    2283             :                  * the overhead of a bitmap if we don't have to.
    2284             :                  */
    2285     1878263 :                 if (info->bytes <= fs_info->sectorsize * 8) {
    2286     1659119 :                         if (ctl->free_extents * 3 <= ctl->extents_thresh)
    2287             :                                 return false;
    2288             :                 } else {
    2289             :                         return false;
    2290             :                 }
    2291             :         }
    2292             : 
    2293             :         /*
    2294             :          * The original block groups from mkfs can be really small, like 8
    2295             :          * megabytes, so don't bother with a bitmap for those entries.  However
    2296             :          * some block groups can be smaller than what a bitmap would cover but
    2297             :          * are still large enough that they could overflow the 32k memory limit,
    2298             :          * so allow those block groups to still be allowed to have a bitmap
    2299             :          * entry.
    2300             :          */
    2301     2923636 :         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
    2302     1305124 :                 return false;
    2303             : 
    2304             :         return true;
    2305             : }
    2306             : 
    2307             : static const struct btrfs_free_space_op free_space_op = {
    2308             :         .use_bitmap             = use_bitmap,
    2309             : };
    2310             : 
    2311     3436182 : static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
    2312             :                               struct btrfs_free_space *info)
    2313             : {
    2314     3436182 :         struct btrfs_free_space *bitmap_info;
    2315     3436182 :         struct btrfs_block_group *block_group = NULL;
    2316     3436182 :         int added = 0;
    2317     3436182 :         u64 bytes, offset, bytes_added;
    2318     3436182 :         enum btrfs_trim_state trim_state;
    2319     3436182 :         int ret;
    2320             : 
    2321     3436182 :         bytes = info->bytes;
    2322     3436182 :         offset = info->offset;
    2323     3436182 :         trim_state = info->trim_state;
    2324             : 
    2325     3436182 :         if (!ctl->op->use_bitmap(ctl, info))
    2326             :                 return 0;
    2327             : 
    2328     1618511 :         if (ctl->op == &free_space_op)
    2329     1618511 :                 block_group = ctl->block_group;
    2330     1618511 : again:
    2331             :         /*
    2332             :          * Since we link bitmaps right into the cluster we need to see if we
    2333             :          * have a cluster here, and if so and it has our bitmap we need to add
    2334             :          * the free space to that bitmap.
    2335             :          */
    2336     1621407 :         if (block_group && !list_empty(&block_group->cluster_list)) {
    2337     1368062 :                 struct btrfs_free_cluster *cluster;
    2338     1368062 :                 struct rb_node *node;
    2339     1368062 :                 struct btrfs_free_space *entry;
    2340             : 
    2341     1368062 :                 cluster = list_entry(block_group->cluster_list.next,
    2342             :                                      struct btrfs_free_cluster,
    2343             :                                      block_group_list);
    2344     1368062 :                 spin_lock(&cluster->lock);
    2345     1368062 :                 node = rb_first(&cluster->root);
    2346     1368062 :                 if (!node) {
    2347         415 :                         spin_unlock(&cluster->lock);
    2348         415 :                         goto no_cluster_bitmap;
    2349             :                 }
    2350             : 
    2351     1367647 :                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
    2352     1367647 :                 if (!entry->bitmap) {
    2353      674170 :                         spin_unlock(&cluster->lock);
    2354      674170 :                         goto no_cluster_bitmap;
    2355             :                 }
    2356             : 
    2357      693477 :                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
    2358      471626 :                         bytes_added = add_bytes_to_bitmap(ctl, entry, offset,
    2359             :                                                           bytes, trim_state);
    2360      471626 :                         bytes -= bytes_added;
    2361      471626 :                         offset += bytes_added;
    2362             :                 }
    2363      693477 :                 spin_unlock(&cluster->lock);
    2364      693477 :                 if (!bytes) {
    2365      471625 :                         ret = 1;
    2366      471625 :                         goto out;
    2367             :                 }
    2368             :         }
    2369             : 
    2370      475197 : no_cluster_bitmap:
    2371     1149782 :         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
    2372             :                                          1, 0);
    2373     1149782 :         if (!bitmap_info) {
    2374        2850 :                 ASSERT(added == 0);
    2375        2850 :                 goto new_bitmap;
    2376             :         }
    2377             : 
    2378     1146932 :         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
    2379             :                                           trim_state);
    2380     1146933 :         bytes -= bytes_added;
    2381     1146933 :         offset += bytes_added;
    2382     1146933 :         added = 0;
    2383             : 
    2384     1146933 :         if (!bytes) {
    2385     1146887 :                 ret = 1;
    2386     1146887 :                 goto out;
    2387             :         } else
    2388          46 :                 goto again;
    2389             : 
    2390             : new_bitmap:
    2391        2850 :         if (info && info->bitmap) {
    2392        1425 :                 add_new_bitmap(ctl, info, offset);
    2393        1425 :                 added = 1;
    2394        1425 :                 info = NULL;
    2395        1425 :                 goto again;
    2396             :         } else {
    2397        1425 :                 spin_unlock(&ctl->tree_lock);
    2398             : 
    2399             :                 /* no pre-allocated info, allocate a new one */
    2400        1425 :                 if (!info) {
    2401           0 :                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
    2402             :                                                  GFP_NOFS);
    2403           0 :                         if (!info) {
    2404           0 :                                 spin_lock(&ctl->tree_lock);
    2405           0 :                                 ret = -ENOMEM;
    2406           0 :                                 goto out;
    2407             :                         }
    2408             :                 }
    2409             : 
    2410             :                 /* allocate the bitmap */
    2411        1425 :                 info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
    2412             :                                                  GFP_NOFS);
    2413        1425 :                 info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
    2414        1425 :                 spin_lock(&ctl->tree_lock);
    2415        1425 :                 if (!info->bitmap) {
    2416           0 :                         ret = -ENOMEM;
    2417           0 :                         goto out;
    2418             :                 }
    2419        1425 :                 goto again;
    2420             :         }
    2421             : 
    2422     1618512 : out:
    2423     1618512 :         if (info) {
    2424     1617087 :                 if (info->bitmap)
    2425           0 :                         kmem_cache_free(btrfs_free_space_bitmap_cachep,
    2426             :                                         info->bitmap);
    2427     1617087 :                 kmem_cache_free(btrfs_free_space_cachep, info);
    2428             :         }
    2429             : 
    2430             :         return ret;
    2431             : }
    2432             : 
    2433             : /*
    2434             :  * Free space merging rules:
    2435             :  *  1) Merge trimmed areas together
    2436             :  *  2) Let untrimmed areas coalesce with trimmed areas
    2437             :  *  3) Always pull neighboring regions from bitmaps
    2438             :  *
    2439             :  * The above rules are for when we merge free space based on btrfs_trim_state.
    2440             :  * Rules 2 and 3 are subtle because they are suboptimal, but are done for the
    2441             :  * same reason: to promote larger extent regions which makes life easier for
    2442             :  * find_free_extent().  Rule 2 enables coalescing based on the common path
    2443             :  * being returning free space from btrfs_finish_extent_commit().  So when free
    2444             :  * space is trimmed, it will prevent aggregating trimmed new region and
    2445             :  * untrimmed regions in the rb_tree.  Rule 3 is purely to obtain larger extents
    2446             :  * and provide find_free_extent() with the largest extents possible hoping for
    2447             :  * the reuse path.
    2448             :  */
    2449     4346687 : static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
    2450             :                           struct btrfs_free_space *info, bool update_stat)
    2451             : {
    2452     4346687 :         struct btrfs_free_space *left_info = NULL;
    2453     4346687 :         struct btrfs_free_space *right_info;
    2454     4346687 :         bool merged = false;
    2455     4346687 :         u64 offset = info->offset;
    2456     4346687 :         u64 bytes = info->bytes;
    2457     4346687 :         const bool is_trimmed = btrfs_free_space_trimmed(info);
    2458     4346687 :         struct rb_node *right_prev = NULL;
    2459             : 
    2460             :         /*
    2461             :          * first we want to see if there is free space adjacent to the range we
    2462             :          * are adding, if there is remove that struct and add a new one to
    2463             :          * cover the entire range
    2464             :          */
    2465     4346687 :         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
    2466     4346688 :         if (right_info)
    2467      595788 :                 right_prev = rb_prev(&right_info->offset_index);
    2468             : 
    2469      595788 :         if (right_prev)
    2470             :                 left_info = rb_entry(right_prev, struct btrfs_free_space, offset_index);
    2471     3791836 :         else if (!right_info)
    2472     3750900 :                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
    2473             : 
    2474             :         /* See try_merge_free_space() comment. */
    2475     4346686 :         if (right_info && !right_info->bitmap &&
    2476        2983 :             (!is_trimmed || btrfs_free_space_trimmed(right_info))) {
    2477      401180 :                 unlink_free_space(ctl, right_info, update_stat);
    2478      401180 :                 info->bytes += right_info->bytes;
    2479      401180 :                 kmem_cache_free(btrfs_free_space_cachep, right_info);
    2480      401180 :                 merged = true;
    2481             :         }
    2482             : 
    2483             :         /* See try_merge_free_space() comment. */
    2484     4346686 :         if (left_info && !left_info->bitmap &&
    2485      855425 :             left_info->offset + left_info->bytes == offset &&
    2486        3341 :             (!is_trimmed || btrfs_free_space_trimmed(left_info))) {
    2487      545867 :                 unlink_free_space(ctl, left_info, update_stat);
    2488      545867 :                 info->offset = left_info->offset;
    2489      545867 :                 info->bytes += left_info->bytes;
    2490      545867 :                 kmem_cache_free(btrfs_free_space_cachep, left_info);
    2491      545867 :                 merged = true;
    2492             :         }
    2493             : 
    2494     4346686 :         return merged;
    2495             : }
    2496             : 
    2497      467783 : static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
    2498             :                                      struct btrfs_free_space *info,
    2499             :                                      bool update_stat)
    2500             : {
    2501      467783 :         struct btrfs_free_space *bitmap;
    2502      467783 :         unsigned long i;
    2503      467783 :         unsigned long j;
    2504      467783 :         const u64 end = info->offset + info->bytes;
    2505      467783 :         const u64 bitmap_offset = offset_to_bitmap(ctl, end);
    2506      467783 :         u64 bytes;
    2507             : 
    2508      467783 :         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
    2509      467783 :         if (!bitmap)
    2510             :                 return false;
    2511             : 
    2512      391686 :         i = offset_to_bit(bitmap->offset, ctl->unit, end);
    2513      391686 :         j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
    2514      391686 :         if (j == i)
    2515             :                 return false;
    2516      103637 :         bytes = (j - i) * ctl->unit;
    2517      103637 :         info->bytes += bytes;
    2518             : 
    2519             :         /* See try_merge_free_space() comment. */
    2520      103637 :         if (!btrfs_free_space_trimmed(bitmap))
    2521      101183 :                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    2522             : 
    2523      103637 :         bitmap_clear_bits(ctl, bitmap, end, bytes, update_stat);
    2524             : 
    2525      103637 :         if (!bitmap->bytes)
    2526         378 :                 free_bitmap(ctl, bitmap);
    2527             : 
    2528             :         return true;
    2529             : }
    2530             : 
    2531      467565 : static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
    2532             :                                        struct btrfs_free_space *info,
    2533             :                                        bool update_stat)
    2534             : {
    2535      467565 :         struct btrfs_free_space *bitmap;
    2536      467565 :         u64 bitmap_offset;
    2537      467565 :         unsigned long i;
    2538      467565 :         unsigned long j;
    2539      467565 :         unsigned long prev_j;
    2540      467565 :         u64 bytes;
    2541             : 
    2542      467565 :         bitmap_offset = offset_to_bitmap(ctl, info->offset);
    2543             :         /* If we're on a boundary, try the previous logical bitmap. */
    2544      467565 :         if (bitmap_offset == info->offset) {
    2545       21512 :                 if (info->offset == 0)
    2546             :                         return false;
    2547       21512 :                 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
    2548             :         }
    2549             : 
    2550      467565 :         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
    2551      467565 :         if (!bitmap)
    2552             :                 return false;
    2553             : 
    2554      367304 :         i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
    2555      367304 :         j = 0;
    2556      367304 :         prev_j = (unsigned long)-1;
    2557  4059780799 :         for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
    2558  4059780784 :                 if (j > i)
    2559             :                         break;
    2560  4059413495 :                 prev_j = j;
    2561             :         }
    2562      367304 :         if (prev_j == i)
    2563             :                 return false;
    2564             : 
    2565       45809 :         if (prev_j == (unsigned long)-1)
    2566          19 :                 bytes = (i + 1) * ctl->unit;
    2567             :         else
    2568       45790 :                 bytes = (i - prev_j) * ctl->unit;
    2569             : 
    2570       45809 :         info->offset -= bytes;
    2571       45809 :         info->bytes += bytes;
    2572             : 
    2573             :         /* See try_merge_free_space() comment. */
    2574       45809 :         if (!btrfs_free_space_trimmed(bitmap))
    2575       45799 :                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    2576             : 
    2577       45809 :         bitmap_clear_bits(ctl, bitmap, info->offset, bytes, update_stat);
    2578             : 
    2579       45809 :         if (!bitmap->bytes)
    2580          29 :                 free_bitmap(ctl, bitmap);
    2581             : 
    2582             :         return true;
    2583             : }
    2584             : 
    2585             : /*
    2586             :  * We prefer always to allocate from extent entries, both for clustered and
    2587             :  * non-clustered allocation requests. So when attempting to add a new extent
    2588             :  * entry, try to see if there's adjacent free space in bitmap entries, and if
    2589             :  * there is, migrate that space from the bitmaps to the extent.
    2590             :  * Like this we get better chances of satisfying space allocation requests
    2591             :  * because we attempt to satisfy them based on a single cache entry, and never
    2592             :  * on 2 or more entries - even if the entries represent a contiguous free space
    2593             :  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
    2594             :  * ends).
    2595             :  */
    2596     2587260 : static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
    2597             :                               struct btrfs_free_space *info,
    2598             :                               bool update_stat)
    2599             : {
    2600             :         /*
    2601             :          * Only work with disconnected entries, as we can change their offset,
    2602             :          * and must be extent entries.
    2603             :          */
    2604     2587260 :         ASSERT(!info->bitmap);
    2605     2587260 :         ASSERT(RB_EMPTY_NODE(&info->offset_index));
    2606             : 
    2607     2587260 :         if (ctl->total_bitmaps > 0) {
    2608      467783 :                 bool stole_end;
    2609      467783 :                 bool stole_front = false;
    2610             : 
    2611      467783 :                 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
    2612      467783 :                 if (ctl->total_bitmaps > 0)
    2613      467565 :                         stole_front = steal_from_bitmap_to_front(ctl, info,
    2614             :                                                                  update_stat);
    2615             : 
    2616      467783 :                 if (stole_end || stole_front)
    2617      140915 :                         try_merge_free_space(ctl, info, update_stat);
    2618             :         }
    2619     2587260 : }
    2620             : 
    2621     4180979 : int __btrfs_add_free_space(struct btrfs_block_group *block_group,
    2622             :                            u64 offset, u64 bytes,
    2623             :                            enum btrfs_trim_state trim_state)
    2624             : {
    2625     4180979 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
    2626     4180979 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    2627     4180979 :         struct btrfs_free_space *info;
    2628     4180979 :         int ret = 0;
    2629     4180979 :         u64 filter_bytes = bytes;
    2630             : 
    2631     4180979 :         ASSERT(!btrfs_is_zoned(fs_info));
    2632             : 
    2633     4180979 :         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
    2634     4180979 :         if (!info)
    2635             :                 return -ENOMEM;
    2636             : 
    2637     4180979 :         info->offset = offset;
    2638     4180979 :         info->bytes = bytes;
    2639     4180979 :         info->trim_state = trim_state;
    2640     4180979 :         RB_CLEAR_NODE(&info->offset_index);
    2641     4180979 :         RB_CLEAR_NODE(&info->bytes_index);
    2642             : 
    2643     4180979 :         spin_lock(&ctl->tree_lock);
    2644             : 
    2645     4180979 :         if (try_merge_free_space(ctl, info, true))
    2646      744796 :                 goto link;
    2647             : 
    2648             :         /*
    2649             :          * There was no extent directly to the left or right of this new
    2650             :          * extent then we know we're going to have to allocate a new extent, so
    2651             :          * before we do that see if we need to drop this into a bitmap
    2652             :          */
    2653     3436182 :         ret = insert_into_bitmap(ctl, info);
    2654     3436182 :         if (ret < 0) {
    2655           0 :                 goto out;
    2656     3436182 :         } else if (ret) {
    2657     1618512 :                 ret = 0;
    2658     1618512 :                 goto out;
    2659             :         }
    2660     1817670 : link:
    2661             :         /*
    2662             :          * Only steal free space from adjacent bitmaps if we're sure we're not
    2663             :          * going to add the new free space to existing bitmap entries - because
    2664             :          * that would mean unnecessary work that would be reverted. Therefore
    2665             :          * attempt to steal space from bitmaps if we're adding an extent entry.
    2666             :          */
    2667     2562466 :         steal_from_bitmap(ctl, info, true);
    2668             : 
    2669     2562466 :         filter_bytes = max(filter_bytes, info->bytes);
    2670             : 
    2671     2562466 :         ret = link_free_space(ctl, info);
    2672     2562467 :         if (ret)
    2673           0 :                 kmem_cache_free(btrfs_free_space_cachep, info);
    2674     2562467 : out:
    2675     4180979 :         btrfs_discard_update_discardable(block_group);
    2676     4180977 :         spin_unlock(&ctl->tree_lock);
    2677             : 
    2678     4180979 :         if (ret) {
    2679           0 :                 btrfs_crit(fs_info, "unable to add free space :%d", ret);
    2680     4180979 :                 ASSERT(ret != -EEXIST);
    2681             :         }
    2682             : 
    2683     4180979 :         if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
    2684     4004266 :                 btrfs_discard_check_filter(block_group, filter_bytes);
    2685     4004266 :                 btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
    2686             :         }
    2687             : 
    2688             :         return ret;
    2689             : }
    2690             : 
    2691             : static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
    2692             :                                         u64 bytenr, u64 size, bool used)
    2693             : {
    2694             :         struct btrfs_space_info *sinfo = block_group->space_info;
    2695             :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    2696             :         u64 offset = bytenr - block_group->start;
    2697             :         u64 to_free, to_unusable;
    2698             :         int bg_reclaim_threshold = 0;
    2699             :         bool initial = (size == block_group->length);
    2700             :         u64 reclaimable_unusable;
    2701             : 
    2702             :         WARN_ON(!initial && offset + size > block_group->zone_capacity);
    2703             : 
    2704             :         if (!initial)
    2705             :                 bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
    2706             : 
    2707             :         spin_lock(&ctl->tree_lock);
    2708             :         /* Count initial region as zone_unusable until it gets activated. */
    2709             :         if (!used)
    2710             :                 to_free = size;
    2711             :         else if (initial &&
    2712             :                  test_bit(BTRFS_FS_ACTIVE_ZONE_TRACKING, &block_group->fs_info->flags) &&
    2713             :                  (block_group->flags & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_SYSTEM)))
    2714             :                 to_free = 0;
    2715             :         else if (initial)
    2716             :                 to_free = block_group->zone_capacity;
    2717             :         else if (offset >= block_group->alloc_offset)
    2718             :                 to_free = size;
    2719             :         else if (offset + size <= block_group->alloc_offset)
    2720             :                 to_free = 0;
    2721             :         else
    2722             :                 to_free = offset + size - block_group->alloc_offset;
    2723             :         to_unusable = size - to_free;
    2724             : 
    2725             :         ctl->free_space += to_free;
    2726             :         /*
    2727             :          * If the block group is read-only, we should account freed space into
    2728             :          * bytes_readonly.
    2729             :          */
    2730             :         if (!block_group->ro)
    2731             :                 block_group->zone_unusable += to_unusable;
    2732             :         spin_unlock(&ctl->tree_lock);
    2733             :         if (!used) {
    2734             :                 spin_lock(&block_group->lock);
    2735             :                 block_group->alloc_offset -= size;
    2736             :                 spin_unlock(&block_group->lock);
    2737             :         }
    2738             : 
    2739             :         reclaimable_unusable = block_group->zone_unusable -
    2740             :                                (block_group->length - block_group->zone_capacity);
    2741             :         /* All the region is now unusable. Mark it as unused and reclaim */
    2742             :         if (block_group->zone_unusable == block_group->length &&
    2743             :             block_group->alloc_offset) {
    2744             :                 btrfs_mark_bg_unused(block_group);
    2745             :         } else if (bg_reclaim_threshold &&
    2746             :                    reclaimable_unusable >=
    2747             :                    mult_perc(block_group->zone_capacity, bg_reclaim_threshold)) {
    2748             :                 btrfs_mark_bg_to_reclaim(block_group);
    2749             :         }
    2750             : 
    2751             :         return 0;
    2752             : }
    2753             : 
    2754     3985607 : int btrfs_add_free_space(struct btrfs_block_group *block_group,
    2755             :                          u64 bytenr, u64 size)
    2756             : {
    2757     3985607 :         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    2758             : 
    2759     3985607 :         if (btrfs_is_zoned(block_group->fs_info))
    2760             :                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
    2761             :                                                     true);
    2762             : 
    2763     3985607 :         if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
    2764          39 :                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
    2765             : 
    2766     3985607 :         return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
    2767             : }
    2768             : 
    2769           0 : int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
    2770             :                                 u64 bytenr, u64 size)
    2771             : {
    2772           0 :         if (btrfs_is_zoned(block_group->fs_info))
    2773             :                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
    2774             :                                                     false);
    2775             : 
    2776           0 :         return btrfs_add_free_space(block_group, bytenr, size);
    2777             : }
    2778             : 
    2779             : /*
    2780             :  * This is a subtle distinction because when adding free space back in general,
    2781             :  * we want it to be added as untrimmed for async. But in the case where we add
    2782             :  * it on loading of a block group, we want to consider it trimmed.
    2783             :  */
    2784      118608 : int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
    2785             :                                        u64 bytenr, u64 size)
    2786             : {
    2787      118608 :         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    2788             : 
    2789      118608 :         if (btrfs_is_zoned(block_group->fs_info))
    2790             :                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
    2791             :                                                     true);
    2792             : 
    2793      118608 :         if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
    2794             :             btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
    2795       99919 :                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
    2796             : 
    2797      118608 :         return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
    2798             : }
    2799             : 
    2800       89246 : int btrfs_remove_free_space(struct btrfs_block_group *block_group,
    2801             :                             u64 offset, u64 bytes)
    2802             : {
    2803       89246 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    2804       89246 :         struct btrfs_free_space *info;
    2805       89246 :         int ret;
    2806       89246 :         bool re_search = false;
    2807             : 
    2808       89246 :         if (btrfs_is_zoned(block_group->fs_info)) {
    2809             :                 /*
    2810             :                  * This can happen with conventional zones when replaying log.
    2811             :                  * Since the allocation info of tree-log nodes are not recorded
    2812             :                  * to the extent-tree, calculate_alloc_pointer() failed to
    2813             :                  * advance the allocation pointer after last allocated tree log
    2814             :                  * node blocks.
    2815             :                  *
    2816             :                  * This function is called from
    2817             :                  * btrfs_pin_extent_for_log_replay() when replaying the log.
    2818             :                  * Advance the pointer not to overwrite the tree-log nodes.
    2819             :                  */
    2820             :                 if (block_group->start + block_group->alloc_offset <
    2821             :                     offset + bytes) {
    2822             :                         block_group->alloc_offset =
    2823             :                                 offset + bytes - block_group->start;
    2824             :                 }
    2825             :                 return 0;
    2826             :         }
    2827             : 
    2828       89246 :         spin_lock(&ctl->tree_lock);
    2829             : 
    2830             : again:
    2831      133186 :         ret = 0;
    2832      133186 :         if (!bytes)
    2833       43940 :                 goto out_lock;
    2834             : 
    2835       89246 :         info = tree_search_offset(ctl, offset, 0, 0);
    2836       89246 :         if (!info) {
    2837             :                 /*
    2838             :                  * oops didn't find an extent that matched the space we wanted
    2839             :                  * to remove, look for a bitmap instead
    2840             :                  */
    2841        1353 :                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
    2842             :                                           1, 0);
    2843        1353 :                 if (!info) {
    2844             :                         /*
    2845             :                          * If we found a partial bit of our free space in a
    2846             :                          * bitmap but then couldn't find the other part this may
    2847             :                          * be a problem, so WARN about it.
    2848             :                          */
    2849           0 :                         WARN_ON(re_search);
    2850           0 :                         goto out_lock;
    2851             :                 }
    2852             :         }
    2853             : 
    2854       89246 :         re_search = false;
    2855       89246 :         if (!info->bitmap) {
    2856       87888 :                 unlink_free_space(ctl, info, true);
    2857       87888 :                 if (offset == info->offset) {
    2858       43940 :                         u64 to_free = min(bytes, info->bytes);
    2859             : 
    2860       43940 :                         info->bytes -= to_free;
    2861       43940 :                         info->offset += to_free;
    2862       43940 :                         if (info->bytes) {
    2863       17231 :                                 ret = link_free_space(ctl, info);
    2864       17231 :                                 WARN_ON(ret);
    2865             :                         } else {
    2866       26709 :                                 kmem_cache_free(btrfs_free_space_cachep, info);
    2867             :                         }
    2868             : 
    2869       43940 :                         offset += to_free;
    2870       43940 :                         bytes -= to_free;
    2871       43940 :                         goto again;
    2872             :                 } else {
    2873       43948 :                         u64 old_end = info->bytes + info->offset;
    2874             : 
    2875       43948 :                         info->bytes = offset - info->offset;
    2876       43948 :                         ret = link_free_space(ctl, info);
    2877       43948 :                         WARN_ON(ret);
    2878       43948 :                         if (ret)
    2879           0 :                                 goto out_lock;
    2880             : 
    2881             :                         /* Not enough bytes in this entry to satisfy us */
    2882       43948 :                         if (old_end < offset + bytes) {
    2883           0 :                                 bytes -= old_end - offset;
    2884           0 :                                 offset = old_end;
    2885           0 :                                 goto again;
    2886       43948 :                         } else if (old_end == offset + bytes) {
    2887             :                                 /* all done */
    2888       15070 :                                 goto out_lock;
    2889             :                         }
    2890       28878 :                         spin_unlock(&ctl->tree_lock);
    2891             : 
    2892       28878 :                         ret = __btrfs_add_free_space(block_group,
    2893             :                                                      offset + bytes,
    2894             :                                                      old_end - (offset + bytes),
    2895             :                                                      info->trim_state);
    2896       28878 :                         WARN_ON(ret);
    2897       28878 :                         goto out;
    2898             :                 }
    2899             :         }
    2900             : 
    2901        1358 :         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
    2902        1358 :         if (ret == -EAGAIN) {
    2903           0 :                 re_search = true;
    2904           0 :                 goto again;
    2905             :         }
    2906        1358 : out_lock:
    2907       60368 :         btrfs_discard_update_discardable(block_group);
    2908       60368 :         spin_unlock(&ctl->tree_lock);
    2909       89246 : out:
    2910       89246 :         return ret;
    2911             : }
    2912             : 
    2913           0 : void btrfs_dump_free_space(struct btrfs_block_group *block_group,
    2914             :                            u64 bytes)
    2915             : {
    2916           0 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
    2917           0 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    2918           0 :         struct btrfs_free_space *info;
    2919           0 :         struct rb_node *n;
    2920           0 :         int count = 0;
    2921             : 
    2922             :         /*
    2923             :          * Zoned btrfs does not use free space tree and cluster. Just print
    2924             :          * out the free space after the allocation offset.
    2925             :          */
    2926           0 :         if (btrfs_is_zoned(fs_info)) {
    2927             :                 btrfs_info(fs_info, "free space %llu active %d",
    2928             :                            block_group->zone_capacity - block_group->alloc_offset,
    2929             :                            test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
    2930             :                                     &block_group->runtime_flags));
    2931             :                 return;
    2932             :         }
    2933             : 
    2934           0 :         spin_lock(&ctl->tree_lock);
    2935           0 :         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
    2936           0 :                 info = rb_entry(n, struct btrfs_free_space, offset_index);
    2937           0 :                 if (info->bytes >= bytes && !block_group->ro)
    2938           0 :                         count++;
    2939           0 :                 btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
    2940             :                            info->offset, info->bytes,
    2941             :                        (info->bitmap) ? "yes" : "no");
    2942             :         }
    2943           0 :         spin_unlock(&ctl->tree_lock);
    2944           0 :         btrfs_info(fs_info, "block group has cluster?: %s",
    2945             :                list_empty(&block_group->cluster_list) ? "no" : "yes");
    2946           0 :         btrfs_info(fs_info,
    2947             :                    "%d blocks of free space at or bigger than bytes is", count);
    2948             : }
    2949             : 
    2950       30799 : void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
    2951             :                                struct btrfs_free_space_ctl *ctl)
    2952             : {
    2953       30799 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
    2954             : 
    2955       30799 :         spin_lock_init(&ctl->tree_lock);
    2956       30799 :         ctl->unit = fs_info->sectorsize;
    2957       30799 :         ctl->start = block_group->start;
    2958       30799 :         ctl->block_group = block_group;
    2959       30799 :         ctl->op = &free_space_op;
    2960       30799 :         ctl->free_space_bytes = RB_ROOT_CACHED;
    2961       30799 :         INIT_LIST_HEAD(&ctl->trimming_ranges);
    2962       30799 :         mutex_init(&ctl->cache_writeout_mutex);
    2963             : 
    2964             :         /*
    2965             :          * we only want to have 32k of ram per block group for keeping
    2966             :          * track of free space, and if we pass 1/2 of that we want to
    2967             :          * start converting things over to using bitmaps
    2968             :          */
    2969       30799 :         ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
    2970       30799 : }
    2971             : 
    2972             : /*
    2973             :  * for a given cluster, put all of its extents back into the free
    2974             :  * space cache.  If the block group passed doesn't match the block group
    2975             :  * pointed to by the cluster, someone else raced in and freed the
    2976             :  * cluster already.  In that case, we just return without changing anything
    2977             :  */
    2978        9791 : static void __btrfs_return_cluster_to_free_space(
    2979             :                              struct btrfs_block_group *block_group,
    2980             :                              struct btrfs_free_cluster *cluster)
    2981             : {
    2982        9791 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    2983        9791 :         struct rb_node *node;
    2984             : 
    2985        9791 :         lockdep_assert_held(&ctl->tree_lock);
    2986             : 
    2987        9791 :         spin_lock(&cluster->lock);
    2988        9791 :         if (cluster->block_group != block_group) {
    2989           0 :                 spin_unlock(&cluster->lock);
    2990           0 :                 return;
    2991             :         }
    2992             : 
    2993        9791 :         cluster->block_group = NULL;
    2994        9791 :         cluster->window_start = 0;
    2995        9791 :         list_del_init(&cluster->block_group_list);
    2996             : 
    2997        9791 :         node = rb_first(&cluster->root);
    2998       34849 :         while (node) {
    2999       25058 :                 struct btrfs_free_space *entry;
    3000             : 
    3001       25058 :                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
    3002       25058 :                 node = rb_next(&entry->offset_index);
    3003       25058 :                 rb_erase(&entry->offset_index, &cluster->root);
    3004       25058 :                 RB_CLEAR_NODE(&entry->offset_index);
    3005             : 
    3006       25058 :                 if (!entry->bitmap) {
    3007             :                         /* Merging treats extents as if they were new */
    3008       24794 :                         if (!btrfs_free_space_trimmed(entry)) {
    3009        2244 :                                 ctl->discardable_extents[BTRFS_STAT_CURR]--;
    3010        2244 :                                 ctl->discardable_bytes[BTRFS_STAT_CURR] -=
    3011        2244 :                                         entry->bytes;
    3012             :                         }
    3013             : 
    3014       24794 :                         try_merge_free_space(ctl, entry, false);
    3015       24794 :                         steal_from_bitmap(ctl, entry, false);
    3016             : 
    3017             :                         /* As we insert directly, update these statistics */
    3018       24794 :                         if (!btrfs_free_space_trimmed(entry)) {
    3019        2277 :                                 ctl->discardable_extents[BTRFS_STAT_CURR]++;
    3020        2277 :                                 ctl->discardable_bytes[BTRFS_STAT_CURR] +=
    3021        2277 :                                         entry->bytes;
    3022             :                         }
    3023             :                 }
    3024       25058 :                 tree_insert_offset(ctl, NULL, entry);
    3025       25058 :                 rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes,
    3026             :                               entry_less);
    3027             :         }
    3028        9791 :         cluster->root = RB_ROOT;
    3029        9791 :         spin_unlock(&cluster->lock);
    3030        9791 :         btrfs_put_block_group(block_group);
    3031             : }
    3032             : 
    3033       30743 : void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
    3034             : {
    3035       30743 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3036       30743 :         struct btrfs_free_cluster *cluster;
    3037       30743 :         struct list_head *head;
    3038             : 
    3039       30743 :         spin_lock(&ctl->tree_lock);
    3040       33894 :         while ((head = block_group->cluster_list.next) !=
    3041       33894 :                &block_group->cluster_list) {
    3042        3151 :                 cluster = list_entry(head, struct btrfs_free_cluster,
    3043             :                                      block_group_list);
    3044             : 
    3045        3151 :                 WARN_ON(cluster->block_group != block_group);
    3046        3151 :                 __btrfs_return_cluster_to_free_space(block_group, cluster);
    3047             : 
    3048        3151 :                 cond_resched_lock(&ctl->tree_lock);
    3049             :         }
    3050       30743 :         __btrfs_remove_free_space_cache(ctl);
    3051       30743 :         btrfs_discard_update_discardable(block_group);
    3052       30743 :         spin_unlock(&ctl->tree_lock);
    3053             : 
    3054       30743 : }
    3055             : 
    3056             : /*
    3057             :  * Walk @block_group's free space rb_tree to determine if everything is trimmed.
    3058             :  */
    3059         152 : bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
    3060             : {
    3061         152 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3062         152 :         struct btrfs_free_space *info;
    3063         152 :         struct rb_node *node;
    3064         152 :         bool ret = true;
    3065             : 
    3066         152 :         spin_lock(&ctl->tree_lock);
    3067         152 :         node = rb_first(&ctl->free_space_offset);
    3068             : 
    3069         255 :         while (node) {
    3070         146 :                 info = rb_entry(node, struct btrfs_free_space, offset_index);
    3071             : 
    3072         146 :                 if (!btrfs_free_space_trimmed(info)) {
    3073             :                         ret = false;
    3074             :                         break;
    3075             :                 }
    3076             : 
    3077         103 :                 node = rb_next(node);
    3078             :         }
    3079             : 
    3080         152 :         spin_unlock(&ctl->tree_lock);
    3081         152 :         return ret;
    3082             : }
    3083             : 
    3084     4442243 : u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
    3085             :                                u64 offset, u64 bytes, u64 empty_size,
    3086             :                                u64 *max_extent_size)
    3087             : {
    3088     4442243 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3089     4442243 :         struct btrfs_discard_ctl *discard_ctl =
    3090     4442243 :                                         &block_group->fs_info->discard_ctl;
    3091     4442243 :         struct btrfs_free_space *entry = NULL;
    3092     4442243 :         u64 bytes_search = bytes + empty_size;
    3093     4442243 :         u64 ret = 0;
    3094     4442243 :         u64 align_gap = 0;
    3095     4442243 :         u64 align_gap_len = 0;
    3096     4442243 :         enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    3097     4442243 :         bool use_bytes_index = (offset == block_group->start);
    3098             : 
    3099     4442243 :         ASSERT(!btrfs_is_zoned(block_group->fs_info));
    3100             : 
    3101     4442243 :         spin_lock(&ctl->tree_lock);
    3102     4442400 :         entry = find_free_space(ctl, &offset, &bytes_search,
    3103             :                                 block_group->full_stripe_len, max_extent_size,
    3104             :                                 use_bytes_index);
    3105     4442397 :         if (!entry)
    3106      274225 :                 goto out;
    3107             : 
    3108     4168172 :         ret = offset;
    3109     4168172 :         if (entry->bitmap) {
    3110      246256 :                 bitmap_clear_bits(ctl, entry, offset, bytes, true);
    3111             : 
    3112      246256 :                 if (!btrfs_free_space_trimmed(entry))
    3113      239538 :                         atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
    3114             : 
    3115      246256 :                 if (!entry->bytes)
    3116         449 :                         free_bitmap(ctl, entry);
    3117             :         } else {
    3118     3921916 :                 unlink_free_space(ctl, entry, true);
    3119     3921909 :                 align_gap_len = offset - entry->offset;
    3120     3921909 :                 align_gap = entry->offset;
    3121     3921909 :                 align_gap_trim_state = entry->trim_state;
    3122             : 
    3123     3921909 :                 if (!btrfs_free_space_trimmed(entry))
    3124     2038868 :                         atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
    3125             : 
    3126     3921913 :                 entry->offset = offset + bytes;
    3127     3921913 :                 WARN_ON(entry->bytes < bytes + align_gap_len);
    3128             : 
    3129     3921913 :                 entry->bytes -= bytes + align_gap_len;
    3130     3921913 :                 if (!entry->bytes)
    3131      234769 :                         kmem_cache_free(btrfs_free_space_cachep, entry);
    3132             :                 else
    3133     3687144 :                         link_free_space(ctl, entry);
    3134             :         }
    3135     4442400 : out:
    3136     4442400 :         btrfs_discard_update_discardable(block_group);
    3137     4442379 :         spin_unlock(&ctl->tree_lock);
    3138             : 
    3139     4442397 :         if (align_gap_len)
    3140           0 :                 __btrfs_add_free_space(block_group, align_gap, align_gap_len,
    3141             :                                        align_gap_trim_state);
    3142     4442397 :         return ret;
    3143             : }
    3144             : 
    3145             : /*
    3146             :  * given a cluster, put all of its extents back into the free space
    3147             :  * cache.  If a block group is passed, this function will only free
    3148             :  * a cluster that belongs to the passed block group.
    3149             :  *
    3150             :  * Otherwise, it'll get a reference on the block group pointed to by the
    3151             :  * cluster and remove the cluster from it.
    3152             :  */
    3153       12637 : void btrfs_return_cluster_to_free_space(
    3154             :                                struct btrfs_block_group *block_group,
    3155             :                                struct btrfs_free_cluster *cluster)
    3156             : {
    3157       12637 :         struct btrfs_free_space_ctl *ctl;
    3158             : 
    3159             :         /* first, get a safe pointer to the block group */
    3160       12637 :         spin_lock(&cluster->lock);
    3161       12637 :         if (!block_group) {
    3162       11571 :                 block_group = cluster->block_group;
    3163       11571 :                 if (!block_group) {
    3164        4931 :                         spin_unlock(&cluster->lock);
    3165        4931 :                         return;
    3166             :                 }
    3167        1066 :         } else if (cluster->block_group != block_group) {
    3168             :                 /* someone else has already freed it don't redo their work */
    3169        1066 :                 spin_unlock(&cluster->lock);
    3170        1066 :                 return;
    3171             :         }
    3172        6640 :         btrfs_get_block_group(block_group);
    3173        6640 :         spin_unlock(&cluster->lock);
    3174             : 
    3175        6640 :         ctl = block_group->free_space_ctl;
    3176             : 
    3177             :         /* now return any extents the cluster had on it */
    3178        6640 :         spin_lock(&ctl->tree_lock);
    3179        6640 :         __btrfs_return_cluster_to_free_space(block_group, cluster);
    3180        6640 :         spin_unlock(&ctl->tree_lock);
    3181             : 
    3182        6640 :         btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group);
    3183             : 
    3184             :         /* finally drop our ref */
    3185        6640 :         btrfs_put_block_group(block_group);
    3186             : }
    3187             : 
    3188     1133132 : static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
    3189             :                                    struct btrfs_free_cluster *cluster,
    3190             :                                    struct btrfs_free_space *entry,
    3191             :                                    u64 bytes, u64 min_start,
    3192             :                                    u64 *max_extent_size)
    3193             : {
    3194     1133132 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3195     1133132 :         int err;
    3196     1133132 :         u64 search_start = cluster->window_start;
    3197     1133132 :         u64 search_bytes = bytes;
    3198     1133132 :         u64 ret = 0;
    3199             : 
    3200     1133132 :         search_start = min_start;
    3201     1133132 :         search_bytes = bytes;
    3202             : 
    3203     1133132 :         err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
    3204     1133132 :         if (err) {
    3205         261 :                 *max_extent_size = max(get_max_extent_size(entry),
    3206             :                                        *max_extent_size);
    3207         261 :                 return 0;
    3208             :         }
    3209             : 
    3210     1132871 :         ret = search_start;
    3211     1132871 :         bitmap_clear_bits(ctl, entry, ret, bytes, false);
    3212             : 
    3213     1132871 :         return ret;
    3214             : }
    3215             : 
    3216             : /*
    3217             :  * given a cluster, try to allocate 'bytes' from it, returns 0
    3218             :  * if it couldn't find anything suitably large, or a logical disk offset
    3219             :  * if things worked out
    3220             :  */
    3221     9100969 : u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
    3222             :                              struct btrfs_free_cluster *cluster, u64 bytes,
    3223             :                              u64 min_start, u64 *max_extent_size)
    3224             : {
    3225     9100969 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3226     9100969 :         struct btrfs_discard_ctl *discard_ctl =
    3227     9100969 :                                         &block_group->fs_info->discard_ctl;
    3228     9100969 :         struct btrfs_free_space *entry = NULL;
    3229     9100969 :         struct rb_node *node;
    3230     9100969 :         u64 ret = 0;
    3231             : 
    3232     9100969 :         ASSERT(!btrfs_is_zoned(block_group->fs_info));
    3233             : 
    3234     9100969 :         spin_lock(&cluster->lock);
    3235     9100969 :         if (bytes > cluster->max_size)
    3236           0 :                 goto out;
    3237             : 
    3238     9100969 :         if (cluster->block_group != block_group)
    3239           0 :                 goto out;
    3240             : 
    3241     9100969 :         node = rb_first(&cluster->root);
    3242     9100969 :         if (!node)
    3243        6289 :                 goto out;
    3244             : 
    3245             :         entry = rb_entry(node, struct btrfs_free_space, offset_index);
    3246     9094804 :         while (1) {
    3247     9094804 :                 if (entry->bytes < bytes)
    3248           0 :                         *max_extent_size = max(get_max_extent_size(entry),
    3249             :                                                *max_extent_size);
    3250             : 
    3251     9094804 :                 if (entry->bytes < bytes ||
    3252     9094804 :                     (!entry->bitmap && entry->offset < min_start)) {
    3253         124 :                         node = rb_next(&entry->offset_index);
    3254         124 :                         if (!node)
    3255             :                                 break;
    3256         124 :                         entry = rb_entry(node, struct btrfs_free_space,
    3257             :                                          offset_index);
    3258         124 :                         continue;
    3259             :                 }
    3260             : 
    3261     9094680 :                 if (entry->bitmap) {
    3262     1133132 :                         ret = btrfs_alloc_from_bitmap(block_group,
    3263             :                                                       cluster, entry, bytes,
    3264             :                                                       cluster->window_start,
    3265             :                                                       max_extent_size);
    3266     1133132 :                         if (ret == 0) {
    3267         261 :                                 node = rb_next(&entry->offset_index);
    3268         261 :                                 if (!node)
    3269             :                                         break;
    3270           0 :                                 entry = rb_entry(node, struct btrfs_free_space,
    3271             :                                                  offset_index);
    3272           0 :                                 continue;
    3273             :                         }
    3274     1132871 :                         cluster->window_start += bytes;
    3275             :                 } else {
    3276     7961548 :                         ret = entry->offset;
    3277             : 
    3278     7961548 :                         entry->offset += bytes;
    3279     7961548 :                         entry->bytes -= bytes;
    3280             :                 }
    3281             : 
    3282             :                 break;
    3283             :         }
    3284         261 : out:
    3285     9100969 :         spin_unlock(&cluster->lock);
    3286             : 
    3287     9100969 :         if (!ret)
    3288             :                 return 0;
    3289             : 
    3290     9094419 :         spin_lock(&ctl->tree_lock);
    3291             : 
    3292     9094419 :         if (!btrfs_free_space_trimmed(entry))
    3293     5981332 :                 atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
    3294             : 
    3295     9094419 :         ctl->free_space -= bytes;
    3296     9094419 :         if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
    3297     4849881 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
    3298             : 
    3299     9094419 :         spin_lock(&cluster->lock);
    3300     9094419 :         if (entry->bytes == 0) {
    3301     1202460 :                 rb_erase(&entry->offset_index, &cluster->root);
    3302     1202460 :                 ctl->free_extents--;
    3303     1202460 :                 if (entry->bitmap) {
    3304         293 :                         kmem_cache_free(btrfs_free_space_bitmap_cachep,
    3305             :                                         entry->bitmap);
    3306         293 :                         ctl->total_bitmaps--;
    3307         293 :                         recalculate_thresholds(ctl);
    3308     1202167 :                 } else if (!btrfs_free_space_trimmed(entry)) {
    3309     1189613 :                         ctl->discardable_extents[BTRFS_STAT_CURR]--;
    3310             :                 }
    3311     1202460 :                 kmem_cache_free(btrfs_free_space_cachep, entry);
    3312             :         }
    3313             : 
    3314     9094419 :         spin_unlock(&cluster->lock);
    3315     9094419 :         spin_unlock(&ctl->tree_lock);
    3316             : 
    3317     9094419 :         return ret;
    3318             : }
    3319             : 
    3320         724 : static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
    3321             :                                 struct btrfs_free_space *entry,
    3322             :                                 struct btrfs_free_cluster *cluster,
    3323             :                                 u64 offset, u64 bytes,
    3324             :                                 u64 cont1_bytes, u64 min_bytes)
    3325             : {
    3326         724 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3327         724 :         unsigned long next_zero;
    3328         724 :         unsigned long i;
    3329         724 :         unsigned long want_bits;
    3330         724 :         unsigned long min_bits;
    3331         724 :         unsigned long found_bits;
    3332         724 :         unsigned long max_bits = 0;
    3333         724 :         unsigned long start = 0;
    3334         724 :         unsigned long total_found = 0;
    3335         724 :         int ret;
    3336             : 
    3337         724 :         lockdep_assert_held(&ctl->tree_lock);
    3338             : 
    3339         724 :         i = offset_to_bit(entry->offset, ctl->unit,
    3340         724 :                           max_t(u64, offset, entry->offset));
    3341         724 :         want_bits = bytes_to_bits(bytes, ctl->unit);
    3342         724 :         min_bits = bytes_to_bits(min_bytes, ctl->unit);
    3343             : 
    3344             :         /*
    3345             :          * Don't bother looking for a cluster in this bitmap if it's heavily
    3346             :          * fragmented.
    3347             :          */
    3348         724 :         if (entry->max_extent_size &&
    3349             :             entry->max_extent_size < cont1_bytes)
    3350             :                 return -ENOSPC;
    3351         724 : again:
    3352        2352 :         found_bits = 0;
    3353        2352 :         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
    3354        2185 :                 next_zero = find_next_zero_bit(entry->bitmap,
    3355             :                                                BITS_PER_BITMAP, i);
    3356        2185 :                 if (next_zero - i >= min_bits) {
    3357        2185 :                         found_bits = next_zero - i;
    3358        2185 :                         if (found_bits > max_bits)
    3359             :                                 max_bits = found_bits;
    3360             :                         break;
    3361             :                 }
    3362           0 :                 if (next_zero - i > max_bits)
    3363             :                         max_bits = next_zero - i;
    3364           0 :                 i = next_zero;
    3365             :         }
    3366             : 
    3367        2352 :         if (!found_bits) {
    3368         167 :                 entry->max_extent_size = (u64)max_bits * ctl->unit;
    3369         167 :                 return -ENOSPC;
    3370             :         }
    3371             : 
    3372        2185 :         if (!total_found) {
    3373         560 :                 start = i;
    3374         560 :                 cluster->max_size = 0;
    3375             :         }
    3376             : 
    3377        2185 :         total_found += found_bits;
    3378             : 
    3379        2185 :         if (cluster->max_size < found_bits * ctl->unit)
    3380         741 :                 cluster->max_size = found_bits * ctl->unit;
    3381             : 
    3382        2185 :         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
    3383        1628 :                 i = next_zero + 1;
    3384        1628 :                 goto again;
    3385             :         }
    3386             : 
    3387         557 :         cluster->window_start = start * ctl->unit + entry->offset;
    3388         557 :         rb_erase(&entry->offset_index, &ctl->free_space_offset);
    3389         557 :         rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
    3390             : 
    3391             :         /*
    3392             :          * We need to know if we're currently on the normal space index when we
    3393             :          * manipulate the bitmap so that we know we need to remove and re-insert
    3394             :          * it into the space_index tree.  Clear the bytes_index node here so the
    3395             :          * bitmap manipulation helpers know not to mess with the space_index
    3396             :          * until this bitmap entry is added back into the normal cache.
    3397             :          */
    3398         557 :         RB_CLEAR_NODE(&entry->bytes_index);
    3399             : 
    3400         557 :         ret = tree_insert_offset(ctl, cluster, entry);
    3401         557 :         ASSERT(!ret); /* -EEXIST; Logic error */
    3402             : 
    3403         557 :         trace_btrfs_setup_cluster(block_group, cluster,
    3404         557 :                                   total_found * ctl->unit, 1);
    3405         557 :         return 0;
    3406             : }
    3407             : 
    3408             : /*
    3409             :  * This searches the block group for just extents to fill the cluster with.
    3410             :  * Try to find a cluster with at least bytes total bytes, at least one
    3411             :  * extent of cont1_bytes, and other clusters of at least min_bytes.
    3412             :  */
    3413             : static noinline int
    3414       10735 : setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
    3415             :                         struct btrfs_free_cluster *cluster,
    3416             :                         struct list_head *bitmaps, u64 offset, u64 bytes,
    3417             :                         u64 cont1_bytes, u64 min_bytes)
    3418             : {
    3419       10735 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3420       10735 :         struct btrfs_free_space *first = NULL;
    3421       10735 :         struct btrfs_free_space *entry = NULL;
    3422       10735 :         struct btrfs_free_space *last;
    3423       10735 :         struct rb_node *node;
    3424       10735 :         u64 window_free;
    3425       10735 :         u64 max_extent;
    3426       10735 :         u64 total_size = 0;
    3427             : 
    3428       10735 :         lockdep_assert_held(&ctl->tree_lock);
    3429             : 
    3430       10735 :         entry = tree_search_offset(ctl, offset, 0, 1);
    3431       10735 :         if (!entry)
    3432             :                 return -ENOSPC;
    3433             : 
    3434             :         /*
    3435             :          * We don't want bitmaps, so just move along until we find a normal
    3436             :          * extent entry.
    3437             :          */
    3438       11290 :         while (entry->bitmap || entry->bytes < min_bytes) {
    3439        1748 :                 if (entry->bitmap && list_empty(&entry->list))
    3440        1745 :                         list_add_tail(&entry->list, bitmaps);
    3441        1748 :                 node = rb_next(&entry->offset_index);
    3442        1748 :                 if (!node)
    3443             :                         return -ENOSPC;
    3444             :                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
    3445             :         }
    3446             : 
    3447        9542 :         window_free = entry->bytes;
    3448        9542 :         max_extent = entry->bytes;
    3449        9542 :         first = entry;
    3450        9542 :         last = entry;
    3451             : 
    3452     1228393 :         for (node = rb_next(&entry->offset_index); node;
    3453     1218851 :              node = rb_next(&entry->offset_index)) {
    3454     1218851 :                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
    3455             : 
    3456     1218851 :                 if (entry->bitmap) {
    3457         830 :                         if (list_empty(&entry->list))
    3458         830 :                                 list_add_tail(&entry->list, bitmaps);
    3459         830 :                         continue;
    3460             :                 }
    3461             : 
    3462     1218021 :                 if (entry->bytes < min_bytes)
    3463           0 :                         continue;
    3464             : 
    3465     1218021 :                 last = entry;
    3466     1218021 :                 window_free += entry->bytes;
    3467     1218021 :                 if (entry->bytes > max_extent)
    3468             :                         max_extent = entry->bytes;
    3469             :         }
    3470             : 
    3471        9542 :         if (window_free < bytes || max_extent < cont1_bytes)
    3472             :                 return -ENOSPC;
    3473             : 
    3474        9234 :         cluster->window_start = first->offset;
    3475             : 
    3476        9234 :         node = &first->offset_index;
    3477             : 
    3478             :         /*
    3479             :          * now we've found our entries, pull them out of the free space
    3480             :          * cache and put them into the cluster rbtree
    3481             :          */
    3482     1227702 :         do {
    3483     1227702 :                 int ret;
    3484             : 
    3485     1227702 :                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
    3486     1227702 :                 node = rb_next(&entry->offset_index);
    3487     1227702 :                 if (entry->bitmap || entry->bytes < min_bytes)
    3488         741 :                         continue;
    3489             : 
    3490     1226961 :                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
    3491     1226961 :                 rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
    3492     1226961 :                 ret = tree_insert_offset(ctl, cluster, entry);
    3493     1226961 :                 total_size += entry->bytes;
    3494     1227702 :                 ASSERT(!ret); /* -EEXIST; Logic error */
    3495     1227702 :         } while (node && entry != last);
    3496             : 
    3497        9234 :         cluster->max_size = max_extent;
    3498        9234 :         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
    3499        9234 :         return 0;
    3500             : }
    3501             : 
    3502             : /*
    3503             :  * This specifically looks for bitmaps that may work in the cluster, we assume
    3504             :  * that we have already failed to find extents that will work.
    3505             :  */
    3506             : static noinline int
    3507        1501 : setup_cluster_bitmap(struct btrfs_block_group *block_group,
    3508             :                      struct btrfs_free_cluster *cluster,
    3509             :                      struct list_head *bitmaps, u64 offset, u64 bytes,
    3510             :                      u64 cont1_bytes, u64 min_bytes)
    3511             : {
    3512        1501 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3513        1501 :         struct btrfs_free_space *entry = NULL;
    3514        1501 :         int ret = -ENOSPC;
    3515        1501 :         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
    3516             : 
    3517        1501 :         if (ctl->total_bitmaps == 0)
    3518             :                 return -ENOSPC;
    3519             : 
    3520             :         /*
    3521             :          * The bitmap that covers offset won't be in the list unless offset
    3522             :          * is just its start offset.
    3523             :          */
    3524        1166 :         if (!list_empty(bitmaps))
    3525        1037 :                 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
    3526             : 
    3527        1037 :         if (!entry || entry->offset != bitmap_offset) {
    3528         473 :                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
    3529         473 :                 if (entry && list_empty(&entry->list))
    3530         265 :                         list_add(&entry->list, bitmaps);
    3531             :         }
    3532             : 
    3533        1884 :         list_for_each_entry(entry, bitmaps, list) {
    3534        1275 :                 if (entry->bytes < bytes)
    3535         551 :                         continue;
    3536         724 :                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
    3537             :                                            bytes, cont1_bytes, min_bytes);
    3538         724 :                 if (!ret)
    3539             :                         return 0;
    3540             :         }
    3541             : 
    3542             :         /*
    3543             :          * The bitmaps list has all the bitmaps that record free space
    3544             :          * starting after offset, so no more search is required.
    3545             :          */
    3546             :         return -ENOSPC;
    3547             : }
    3548             : 
    3549             : /*
    3550             :  * here we try to find a cluster of blocks in a block group.  The goal
    3551             :  * is to find at least bytes+empty_size.
    3552             :  * We might not find them all in one contiguous area.
    3553             :  *
    3554             :  * returns zero and sets up cluster if things worked out, otherwise
    3555             :  * it returns -enospc
    3556             :  */
    3557       16948 : int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
    3558             :                              struct btrfs_free_cluster *cluster,
    3559             :                              u64 offset, u64 bytes, u64 empty_size)
    3560             : {
    3561       16948 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
    3562       16948 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3563       16948 :         struct btrfs_free_space *entry, *tmp;
    3564       16948 :         LIST_HEAD(bitmaps);
    3565       16948 :         u64 min_bytes;
    3566       16948 :         u64 cont1_bytes;
    3567       16948 :         int ret;
    3568             : 
    3569             :         /*
    3570             :          * Choose the minimum extent size we'll require for this
    3571             :          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
    3572             :          * For metadata, allow allocates with smaller extents.  For
    3573             :          * data, keep it dense.
    3574             :          */
    3575       16948 :         if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
    3576           3 :                 cont1_bytes = bytes + empty_size;
    3577           3 :                 min_bytes = cont1_bytes;
    3578       16945 :         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
    3579       16945 :                 cont1_bytes = bytes;
    3580       16945 :                 min_bytes = fs_info->sectorsize;
    3581             :         } else {
    3582           0 :                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
    3583           0 :                 min_bytes = fs_info->sectorsize;
    3584             :         }
    3585             : 
    3586       16948 :         spin_lock(&ctl->tree_lock);
    3587             : 
    3588             :         /*
    3589             :          * If we know we don't have enough space to make a cluster don't even
    3590             :          * bother doing all the work to try and find one.
    3591             :          */
    3592       16948 :         if (ctl->free_space < bytes) {
    3593        6213 :                 spin_unlock(&ctl->tree_lock);
    3594        6213 :                 return -ENOSPC;
    3595             :         }
    3596             : 
    3597       10735 :         spin_lock(&cluster->lock);
    3598             : 
    3599             :         /* someone already found a cluster, hooray */
    3600       10735 :         if (cluster->block_group) {
    3601           0 :                 ret = 0;
    3602           0 :                 goto out;
    3603             :         }
    3604             : 
    3605       10735 :         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
    3606             :                                  min_bytes);
    3607             : 
    3608       10735 :         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
    3609             :                                       bytes + empty_size,
    3610             :                                       cont1_bytes, min_bytes);
    3611       10735 :         if (ret)
    3612        1501 :                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
    3613             :                                            offset, bytes + empty_size,
    3614             :                                            cont1_bytes, min_bytes);
    3615             : 
    3616             :         /* Clear our temporary list */
    3617       13575 :         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
    3618        2840 :                 list_del_init(&entry->list);
    3619             : 
    3620       10735 :         if (!ret) {
    3621        9791 :                 btrfs_get_block_group(block_group);
    3622        9791 :                 list_add_tail(&cluster->block_group_list,
    3623             :                               &block_group->cluster_list);
    3624        9791 :                 cluster->block_group = block_group;
    3625             :         } else {
    3626         944 :                 trace_btrfs_failed_cluster_setup(block_group);
    3627             :         }
    3628       10735 : out:
    3629       10735 :         spin_unlock(&cluster->lock);
    3630       10735 :         spin_unlock(&ctl->tree_lock);
    3631             : 
    3632       10735 :         return ret;
    3633             : }
    3634             : 
    3635             : /*
    3636             :  * simple code to zero out a cluster
    3637             :  */
    3638        6946 : void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
    3639             : {
    3640        6946 :         spin_lock_init(&cluster->lock);
    3641        6946 :         spin_lock_init(&cluster->refill_lock);
    3642        6946 :         cluster->root = RB_ROOT;
    3643        6946 :         cluster->max_size = 0;
    3644        6946 :         cluster->fragmented = false;
    3645        6946 :         INIT_LIST_HEAD(&cluster->block_group_list);
    3646        6946 :         cluster->block_group = NULL;
    3647        6946 : }
    3648             : 
    3649       47881 : static int do_trimming(struct btrfs_block_group *block_group,
    3650             :                        u64 *total_trimmed, u64 start, u64 bytes,
    3651             :                        u64 reserved_start, u64 reserved_bytes,
    3652             :                        enum btrfs_trim_state reserved_trim_state,
    3653             :                        struct btrfs_trim_range *trim_entry)
    3654             : {
    3655       47881 :         struct btrfs_space_info *space_info = block_group->space_info;
    3656       47881 :         struct btrfs_fs_info *fs_info = block_group->fs_info;
    3657       47881 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3658       47881 :         int ret;
    3659       47881 :         int update = 0;
    3660       47881 :         const u64 end = start + bytes;
    3661       47881 :         const u64 reserved_end = reserved_start + reserved_bytes;
    3662       47881 :         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    3663       47881 :         u64 trimmed = 0;
    3664             : 
    3665       47881 :         spin_lock(&space_info->lock);
    3666       47881 :         spin_lock(&block_group->lock);
    3667       47881 :         if (!block_group->ro) {
    3668       47881 :                 block_group->reserved += reserved_bytes;
    3669       47881 :                 space_info->bytes_reserved += reserved_bytes;
    3670       47881 :                 update = 1;
    3671             :         }
    3672       47881 :         spin_unlock(&block_group->lock);
    3673       47881 :         spin_unlock(&space_info->lock);
    3674             : 
    3675       47881 :         ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
    3676       47881 :         if (!ret) {
    3677       47880 :                 *total_trimmed += trimmed;
    3678       47880 :                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
    3679             :         }
    3680             : 
    3681       47881 :         mutex_lock(&ctl->cache_writeout_mutex);
    3682       47880 :         if (reserved_start < start)
    3683           1 :                 __btrfs_add_free_space(block_group, reserved_start,
    3684             :                                        start - reserved_start,
    3685             :                                        reserved_trim_state);
    3686       47880 :         if (end < reserved_end)
    3687           4 :                 __btrfs_add_free_space(block_group, end, reserved_end - end,
    3688             :                                        reserved_trim_state);
    3689       47880 :         __btrfs_add_free_space(block_group, start, bytes, trim_state);
    3690       47881 :         list_del(&trim_entry->list);
    3691       47881 :         mutex_unlock(&ctl->cache_writeout_mutex);
    3692             : 
    3693       47881 :         if (update) {
    3694       47881 :                 spin_lock(&space_info->lock);
    3695       47881 :                 spin_lock(&block_group->lock);
    3696       47881 :                 if (block_group->ro)
    3697           0 :                         space_info->bytes_readonly += reserved_bytes;
    3698       47881 :                 block_group->reserved -= reserved_bytes;
    3699       47881 :                 space_info->bytes_reserved -= reserved_bytes;
    3700       47881 :                 spin_unlock(&block_group->lock);
    3701       47881 :                 spin_unlock(&space_info->lock);
    3702             :         }
    3703             : 
    3704       47881 :         return ret;
    3705             : }
    3706             : 
    3707             : /*
    3708             :  * If @async is set, then we will trim 1 region and return.
    3709             :  */
    3710        4925 : static int trim_no_bitmap(struct btrfs_block_group *block_group,
    3711             :                           u64 *total_trimmed, u64 start, u64 end, u64 minlen,
    3712             :                           bool async)
    3713             : {
    3714        4925 :         struct btrfs_discard_ctl *discard_ctl =
    3715        4925 :                                         &block_group->fs_info->discard_ctl;
    3716        4925 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3717        4925 :         struct btrfs_free_space *entry;
    3718        4925 :         struct rb_node *node;
    3719        4925 :         int ret = 0;
    3720        4925 :         u64 extent_start;
    3721        4925 :         u64 extent_bytes;
    3722        4925 :         enum btrfs_trim_state extent_trim_state;
    3723        4925 :         u64 bytes;
    3724        4925 :         const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
    3725             : 
    3726      165976 :         while (start < end) {
    3727      163275 :                 struct btrfs_trim_range trim_entry;
    3728             : 
    3729      163275 :                 mutex_lock(&ctl->cache_writeout_mutex);
    3730      163276 :                 spin_lock(&ctl->tree_lock);
    3731             : 
    3732      163276 :                 if (ctl->free_space < minlen)
    3733         763 :                         goto out_unlock;
    3734             : 
    3735      162513 :                 entry = tree_search_offset(ctl, start, 0, 1);
    3736      162513 :                 if (!entry)
    3737         420 :                         goto out_unlock;
    3738             : 
    3739             :                 /* Skip bitmaps and if async, already trimmed entries */
    3740      164471 :                 while (entry->bitmap ||
    3741        3893 :                        (async && btrfs_free_space_trimmed(entry))) {
    3742        2428 :                         node = rb_next(&entry->offset_index);
    3743        2428 :                         if (!node)
    3744          50 :                                 goto out_unlock;
    3745             :                         entry = rb_entry(node, struct btrfs_free_space,
    3746             :                                          offset_index);
    3747             :                 }
    3748             : 
    3749      162043 :                 if (entry->offset >= end)
    3750           2 :                         goto out_unlock;
    3751             : 
    3752      162041 :                 extent_start = entry->offset;
    3753      162041 :                 extent_bytes = entry->bytes;
    3754      162041 :                 extent_trim_state = entry->trim_state;
    3755      162041 :                 if (async) {
    3756        3706 :                         start = entry->offset;
    3757        3706 :                         bytes = entry->bytes;
    3758        3706 :                         if (bytes < minlen) {
    3759        2722 :                                 spin_unlock(&ctl->tree_lock);
    3760        2722 :                                 mutex_unlock(&ctl->cache_writeout_mutex);
    3761        2722 :                                 goto next;
    3762             :                         }
    3763         984 :                         unlink_free_space(ctl, entry, true);
    3764             :                         /*
    3765             :                          * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
    3766             :                          * If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
    3767             :                          * X when we come back around.  So trim it now.
    3768             :                          */
    3769         984 :                         if (max_discard_size &&
    3770         984 :                             bytes >= (max_discard_size +
    3771             :                                       BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
    3772         805 :                                 bytes = max_discard_size;
    3773         805 :                                 extent_bytes = max_discard_size;
    3774         805 :                                 entry->offset += max_discard_size;
    3775         805 :                                 entry->bytes -= max_discard_size;
    3776         805 :                                 link_free_space(ctl, entry);
    3777             :                         } else {
    3778         179 :                                 kmem_cache_free(btrfs_free_space_cachep, entry);
    3779             :                         }
    3780             :                 } else {
    3781      158335 :                         start = max(start, extent_start);
    3782      158335 :                         bytes = min(extent_start + extent_bytes, end) - start;
    3783      158335 :                         if (bytes < minlen) {
    3784      134331 :                                 spin_unlock(&ctl->tree_lock);
    3785      134331 :                                 mutex_unlock(&ctl->cache_writeout_mutex);
    3786      134331 :                                 goto next;
    3787             :                         }
    3788             : 
    3789       24004 :                         unlink_free_space(ctl, entry, true);
    3790       24004 :                         kmem_cache_free(btrfs_free_space_cachep, entry);
    3791             :                 }
    3792             : 
    3793       24988 :                 spin_unlock(&ctl->tree_lock);
    3794       24988 :                 trim_entry.start = extent_start;
    3795       24988 :                 trim_entry.bytes = extent_bytes;
    3796       24988 :                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
    3797       24988 :                 mutex_unlock(&ctl->cache_writeout_mutex);
    3798             : 
    3799       24988 :                 ret = do_trimming(block_group, total_trimmed, start, bytes,
    3800             :                                   extent_start, extent_bytes, extent_trim_state,
    3801             :                                   &trim_entry);
    3802       24987 :                 if (ret) {
    3803           0 :                         block_group->discard_cursor = start + bytes;
    3804         989 :                         break;
    3805             :                 }
    3806       24987 : next:
    3807      162040 :                 start += bytes;
    3808      162040 :                 block_group->discard_cursor = start;
    3809      162040 :                 if (async && *total_trimmed)
    3810             :                         break;
    3811             : 
    3812      161056 :                 if (fatal_signal_pending(current)) {
    3813             :                         ret = -ERESTARTSYS;
    3814             :                         break;
    3815             :                 }
    3816             : 
    3817      161051 :                 cond_resched();
    3818             :         }
    3819             : 
    3820             :         return ret;
    3821             : 
    3822             : out_unlock:
    3823        1235 :         block_group->discard_cursor = btrfs_block_group_end(block_group);
    3824        1235 :         spin_unlock(&ctl->tree_lock);
    3825        1235 :         mutex_unlock(&ctl->cache_writeout_mutex);
    3826             : 
    3827        1235 :         return ret;
    3828             : }
    3829             : 
    3830             : /*
    3831             :  * If we break out of trimming a bitmap prematurely, we should reset the
    3832             :  * trimming bit.  In a rather contrieved case, it's possible to race here so
    3833             :  * reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
    3834             :  *
    3835             :  * start = start of bitmap
    3836             :  * end = near end of bitmap
    3837             :  *
    3838             :  * Thread 1:                    Thread 2:
    3839             :  * trim_bitmaps(start)
    3840             :  *                              trim_bitmaps(end)
    3841             :  *                              end_trimming_bitmap()
    3842             :  * reset_trimming_bitmap()
    3843             :  */
    3844        3890 : static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
    3845             : {
    3846        3890 :         struct btrfs_free_space *entry;
    3847             : 
    3848        3890 :         spin_lock(&ctl->tree_lock);
    3849        3890 :         entry = tree_search_offset(ctl, offset, 1, 0);
    3850        3890 :         if (entry) {
    3851           2 :                 if (btrfs_free_space_trimmed(entry)) {
    3852           0 :                         ctl->discardable_extents[BTRFS_STAT_CURR] +=
    3853           0 :                                 entry->bitmap_extents;
    3854           0 :                         ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
    3855             :                 }
    3856           2 :                 entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    3857             :         }
    3858             : 
    3859        3890 :         spin_unlock(&ctl->tree_lock);
    3860        3890 : }
    3861             : 
    3862             : static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
    3863             :                                 struct btrfs_free_space *entry)
    3864             : {
    3865         331 :         if (btrfs_free_space_trimming_bitmap(entry)) {
    3866         322 :                 entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
    3867         322 :                 ctl->discardable_extents[BTRFS_STAT_CURR] -=
    3868         322 :                         entry->bitmap_extents;
    3869         322 :                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
    3870             :         }
    3871             : }
    3872             : 
    3873             : /*
    3874             :  * If @async is set, then we will trim 1 region and return.
    3875             :  */
    3876        4014 : static int trim_bitmaps(struct btrfs_block_group *block_group,
    3877             :                         u64 *total_trimmed, u64 start, u64 end, u64 minlen,
    3878             :                         u64 maxlen, bool async)
    3879             : {
    3880        4014 :         struct btrfs_discard_ctl *discard_ctl =
    3881        4014 :                                         &block_group->fs_info->discard_ctl;
    3882        4014 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    3883        4014 :         struct btrfs_free_space *entry;
    3884        4014 :         int ret = 0;
    3885        4014 :         int ret2;
    3886        4014 :         u64 bytes;
    3887        4014 :         u64 offset = offset_to_bitmap(ctl, start);
    3888        4014 :         const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
    3889             : 
    3890       43747 :         while (offset < end) {
    3891       40496 :                 bool next_bitmap = false;
    3892       40496 :                 struct btrfs_trim_range trim_entry;
    3893             : 
    3894       40496 :                 mutex_lock(&ctl->cache_writeout_mutex);
    3895       40496 :                 spin_lock(&ctl->tree_lock);
    3896             : 
    3897       40496 :                 if (ctl->free_space < minlen) {
    3898         763 :                         block_group->discard_cursor =
    3899             :                                 btrfs_block_group_end(block_group);
    3900         763 :                         spin_unlock(&ctl->tree_lock);
    3901         763 :                         mutex_unlock(&ctl->cache_writeout_mutex);
    3902        1526 :                         break;
    3903             :                 }
    3904             : 
    3905       39733 :                 entry = tree_search_offset(ctl, offset, 1, 0);
    3906             :                 /*
    3907             :                  * Bitmaps are marked trimmed lossily now to prevent constant
    3908             :                  * discarding of the same bitmap (the reason why we are bound
    3909             :                  * by the filters).  So, retrim the block group bitmaps when we
    3910             :                  * are preparing to punt to the unused_bgs list.  This uses
    3911             :                  * @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
    3912             :                  * which is the only discard index which sets minlen to 0.
    3913             :                  */
    3914       39733 :                 if (!entry || (async && minlen && start == offset &&
    3915             :                                btrfs_free_space_trimmed(entry))) {
    3916       14631 :                         spin_unlock(&ctl->tree_lock);
    3917       14631 :                         mutex_unlock(&ctl->cache_writeout_mutex);
    3918       14631 :                         next_bitmap = true;
    3919       14631 :                         goto next;
    3920             :                 }
    3921             : 
    3922             :                 /*
    3923             :                  * Async discard bitmap trimming begins at by setting the start
    3924             :                  * to be key.objectid and the offset_to_bitmap() aligns to the
    3925             :                  * start of the bitmap.  This lets us know we are fully
    3926             :                  * scanning the bitmap rather than only some portion of it.
    3927             :                  */
    3928       25102 :                 if (start == offset)
    3929        2207 :                         entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
    3930             : 
    3931       25102 :                 bytes = minlen;
    3932       25102 :                 ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
    3933       25102 :                 if (ret2 || start >= end) {
    3934             :                         /*
    3935             :                          * We lossily consider a bitmap trimmed if we only skip
    3936             :                          * over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
    3937             :                          */
    3938        2207 :                         if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
    3939         331 :                                 end_trimming_bitmap(ctl, entry);
    3940             :                         else
    3941        1876 :                                 entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
    3942        2207 :                         spin_unlock(&ctl->tree_lock);
    3943        2207 :                         mutex_unlock(&ctl->cache_writeout_mutex);
    3944        2207 :                         next_bitmap = true;
    3945        2207 :                         goto next;
    3946             :                 }
    3947             : 
    3948             :                 /*
    3949             :                  * We already trimmed a region, but are using the locking above
    3950             :                  * to reset the trim_state.
    3951             :                  */
    3952       22895 :                 if (async && *total_trimmed) {
    3953           0 :                         spin_unlock(&ctl->tree_lock);
    3954           0 :                         mutex_unlock(&ctl->cache_writeout_mutex);
    3955           0 :                         goto out;
    3956             :                 }
    3957             : 
    3958       22895 :                 bytes = min(bytes, end - start);
    3959       22895 :                 if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
    3960           2 :                         spin_unlock(&ctl->tree_lock);
    3961           2 :                         mutex_unlock(&ctl->cache_writeout_mutex);
    3962           2 :                         goto next;
    3963             :                 }
    3964             : 
    3965             :                 /*
    3966             :                  * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
    3967             :                  * If X < @minlen, we won't trim X when we come back around.
    3968             :                  * So trim it now.  We differ here from trimming extents as we
    3969             :                  * don't keep individual state per bit.
    3970             :                  */
    3971       22893 :                 if (async &&
    3972           0 :                     max_discard_size &&
    3973           0 :                     bytes > (max_discard_size + minlen))
    3974           0 :                         bytes = max_discard_size;
    3975             : 
    3976       22893 :                 bitmap_clear_bits(ctl, entry, start, bytes, true);
    3977       22893 :                 if (entry->bytes == 0)
    3978           0 :                         free_bitmap(ctl, entry);
    3979             : 
    3980       22893 :                 spin_unlock(&ctl->tree_lock);
    3981       22893 :                 trim_entry.start = start;
    3982       22893 :                 trim_entry.bytes = bytes;
    3983       22893 :                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
    3984       22893 :                 mutex_unlock(&ctl->cache_writeout_mutex);
    3985             : 
    3986       22893 :                 ret = do_trimming(block_group, total_trimmed, start, bytes,
    3987             :                                   start, bytes, 0, &trim_entry);
    3988       22893 :                 if (ret) {
    3989           0 :                         reset_trimming_bitmap(ctl, offset);
    3990           0 :                         block_group->discard_cursor =
    3991             :                                 btrfs_block_group_end(block_group);
    3992           0 :                         break;
    3993             :                 }
    3994       22893 : next:
    3995       16840 :                 if (next_bitmap) {
    3996       16838 :                         offset += BITS_PER_BITMAP * ctl->unit;
    3997       16838 :                         start = offset;
    3998             :                 } else {
    3999       22895 :                         start += bytes;
    4000             :                 }
    4001       39733 :                 block_group->discard_cursor = start;
    4002             : 
    4003       39733 :                 if (fatal_signal_pending(current)) {
    4004           0 :                         if (start != offset)
    4005           0 :                                 reset_trimming_bitmap(ctl, offset);
    4006             :                         ret = -ERESTARTSYS;
    4007             :                         break;
    4008             :                 }
    4009             : 
    4010       39733 :                 cond_resched();
    4011             :         }
    4012             : 
    4013        4014 :         if (offset >= end)
    4014        3251 :                 block_group->discard_cursor = end;
    4015             : 
    4016         763 : out:
    4017        4014 :         return ret;
    4018             : }
    4019             : 
    4020        3895 : int btrfs_trim_block_group(struct btrfs_block_group *block_group,
    4021             :                            u64 *trimmed, u64 start, u64 end, u64 minlen)
    4022             : {
    4023        3895 :         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
    4024        3895 :         int ret;
    4025        3895 :         u64 rem = 0;
    4026             : 
    4027        3895 :         ASSERT(!btrfs_is_zoned(block_group->fs_info));
    4028             : 
    4029        3895 :         *trimmed = 0;
    4030             : 
    4031        3895 :         spin_lock(&block_group->lock);
    4032        7790 :         if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
    4033           0 :                 spin_unlock(&block_group->lock);
    4034           0 :                 return 0;
    4035             :         }
    4036        3895 :         btrfs_freeze_block_group(block_group);
    4037        3895 :         spin_unlock(&block_group->lock);
    4038             : 
    4039        3895 :         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false);
    4040        3895 :         if (ret)
    4041           5 :                 goto out;
    4042             : 
    4043        3890 :         ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false);
    4044        3890 :         div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem);
    4045             :         /* If we ended in the middle of a bitmap, reset the trimming flag */
    4046        3890 :         if (rem)
    4047        3890 :                 reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end));
    4048           0 : out:
    4049        3895 :         btrfs_unfreeze_block_group(block_group);
    4050        3895 :         return ret;
    4051             : }
    4052             : 
    4053        1030 : int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
    4054             :                                    u64 *trimmed, u64 start, u64 end, u64 minlen,
    4055             :                                    bool async)
    4056             : {
    4057        1030 :         int ret;
    4058             : 
    4059        1030 :         *trimmed = 0;
    4060             : 
    4061        1030 :         spin_lock(&block_group->lock);
    4062        2060 :         if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
    4063           0 :                 spin_unlock(&block_group->lock);
    4064           0 :                 return 0;
    4065             :         }
    4066        1030 :         btrfs_freeze_block_group(block_group);
    4067        1030 :         spin_unlock(&block_group->lock);
    4068             : 
    4069        1030 :         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async);
    4070        1030 :         btrfs_unfreeze_block_group(block_group);
    4071             : 
    4072        1030 :         return ret;
    4073             : }
    4074             : 
    4075         124 : int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
    4076             :                                    u64 *trimmed, u64 start, u64 end, u64 minlen,
    4077             :                                    u64 maxlen, bool async)
    4078             : {
    4079         124 :         int ret;
    4080             : 
    4081         124 :         *trimmed = 0;
    4082             : 
    4083         124 :         spin_lock(&block_group->lock);
    4084         248 :         if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
    4085           0 :                 spin_unlock(&block_group->lock);
    4086           0 :                 return 0;
    4087             :         }
    4088         124 :         btrfs_freeze_block_group(block_group);
    4089         124 :         spin_unlock(&block_group->lock);
    4090             : 
    4091         124 :         ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen,
    4092             :                            async);
    4093             : 
    4094         124 :         btrfs_unfreeze_block_group(block_group);
    4095             : 
    4096         124 :         return ret;
    4097             : }
    4098             : 
    4099     1262511 : bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
    4100             : {
    4101     1262511 :         return btrfs_super_cache_generation(fs_info->super_copy);
    4102             : }
    4103             : 
    4104           2 : static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
    4105             :                                        struct btrfs_trans_handle *trans)
    4106             : {
    4107           2 :         struct btrfs_block_group *block_group;
    4108           2 :         struct rb_node *node;
    4109           2 :         int ret = 0;
    4110             : 
    4111           2 :         btrfs_info(fs_info, "cleaning free space cache v1");
    4112             : 
    4113           2 :         node = rb_first_cached(&fs_info->block_group_cache_tree);
    4114           8 :         while (node) {
    4115           6 :                 block_group = rb_entry(node, struct btrfs_block_group, cache_node);
    4116           6 :                 ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
    4117           6 :                 if (ret)
    4118           0 :                         goto out;
    4119           6 :                 node = rb_next(node);
    4120             :         }
    4121           2 : out:
    4122           2 :         return ret;
    4123             : }
    4124             : 
    4125           2 : int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
    4126             : {
    4127           2 :         struct btrfs_trans_handle *trans;
    4128           2 :         int ret;
    4129             : 
    4130             :         /*
    4131             :          * update_super_roots will appropriately set or unset
    4132             :          * super_copy->cache_generation based on SPACE_CACHE and
    4133             :          * BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
    4134             :          * transaction commit whether we are enabling space cache v1 and don't
    4135             :          * have any other work to do, or are disabling it and removing free
    4136             :          * space inodes.
    4137             :          */
    4138           2 :         trans = btrfs_start_transaction(fs_info->tree_root, 0);
    4139           2 :         if (IS_ERR(trans))
    4140           0 :                 return PTR_ERR(trans);
    4141             : 
    4142           2 :         if (!active) {
    4143           2 :                 set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
    4144           2 :                 ret = cleanup_free_space_cache_v1(fs_info, trans);
    4145           2 :                 if (ret) {
    4146           0 :                         btrfs_abort_transaction(trans, ret);
    4147           0 :                         btrfs_end_transaction(trans);
    4148           0 :                         goto out;
    4149             :                 }
    4150             :         }
    4151             : 
    4152           2 :         ret = btrfs_commit_transaction(trans);
    4153           2 : out:
    4154           2 :         clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
    4155             : 
    4156           2 :         return ret;
    4157             : }
    4158             : 
    4159          11 : int __init btrfs_free_space_init(void)
    4160             : {
    4161          11 :         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
    4162             :                         sizeof(struct btrfs_free_space), 0,
    4163             :                         SLAB_MEM_SPREAD, NULL);
    4164          11 :         if (!btrfs_free_space_cachep)
    4165             :                 return -ENOMEM;
    4166             : 
    4167          11 :         btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
    4168             :                                                         PAGE_SIZE, PAGE_SIZE,
    4169             :                                                         SLAB_MEM_SPREAD, NULL);
    4170          11 :         if (!btrfs_free_space_bitmap_cachep) {
    4171           0 :                 kmem_cache_destroy(btrfs_free_space_cachep);
    4172           0 :                 return -ENOMEM;
    4173             :         }
    4174             : 
    4175             :         return 0;
    4176             : }
    4177             : 
    4178           0 : void __cold btrfs_free_space_exit(void)
    4179             : {
    4180           0 :         kmem_cache_destroy(btrfs_free_space_cachep);
    4181           0 :         kmem_cache_destroy(btrfs_free_space_bitmap_cachep);
    4182           0 : }
    4183             : 
    4184             : #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
    4185             : /*
    4186             :  * Use this if you need to make a bitmap or extent entry specifically, it
    4187             :  * doesn't do any of the merging that add_free_space does, this acts a lot like
    4188             :  * how the free space cache loading stuff works, so you can get really weird
    4189             :  * configurations.
    4190             :  */
    4191             : int test_add_free_space_entry(struct btrfs_block_group *cache,
    4192             :                               u64 offset, u64 bytes, bool bitmap)
    4193             : {
    4194             :         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
    4195             :         struct btrfs_free_space *info = NULL, *bitmap_info;
    4196             :         void *map = NULL;
    4197             :         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
    4198             :         u64 bytes_added;
    4199             :         int ret;
    4200             : 
    4201             : again:
    4202             :         if (!info) {
    4203             :                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
    4204             :                 if (!info)
    4205             :                         return -ENOMEM;
    4206             :         }
    4207             : 
    4208             :         if (!bitmap) {
    4209             :                 spin_lock(&ctl->tree_lock);
    4210             :                 info->offset = offset;
    4211             :                 info->bytes = bytes;
    4212             :                 info->max_extent_size = 0;
    4213             :                 ret = link_free_space(ctl, info);
    4214             :                 spin_unlock(&ctl->tree_lock);
    4215             :                 if (ret)
    4216             :                         kmem_cache_free(btrfs_free_space_cachep, info);
    4217             :                 return ret;
    4218             :         }
    4219             : 
    4220             :         if (!map) {
    4221             :                 map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
    4222             :                 if (!map) {
    4223             :                         kmem_cache_free(btrfs_free_space_cachep, info);
    4224             :                         return -ENOMEM;
    4225             :                 }
    4226             :         }
    4227             : 
    4228             :         spin_lock(&ctl->tree_lock);
    4229             :         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
    4230             :                                          1, 0);
    4231             :         if (!bitmap_info) {
    4232             :                 info->bitmap = map;
    4233             :                 map = NULL;
    4234             :                 add_new_bitmap(ctl, info, offset);
    4235             :                 bitmap_info = info;
    4236             :                 info = NULL;
    4237             :         }
    4238             : 
    4239             :         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
    4240             :                                           trim_state);
    4241             : 
    4242             :         bytes -= bytes_added;
    4243             :         offset += bytes_added;
    4244             :         spin_unlock(&ctl->tree_lock);
    4245             : 
    4246             :         if (bytes)
    4247             :                 goto again;
    4248             : 
    4249             :         if (info)
    4250             :                 kmem_cache_free(btrfs_free_space_cachep, info);
    4251             :         if (map)
    4252             :                 kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
    4253             :         return 0;
    4254             : }
    4255             : 
    4256             : /*
    4257             :  * Checks to see if the given range is in the free space cache.  This is really
    4258             :  * just used to check the absence of space, so if there is free space in the
    4259             :  * range at all we will return 1.
    4260             :  */
    4261             : int test_check_exists(struct btrfs_block_group *cache,
    4262             :                       u64 offset, u64 bytes)
    4263             : {
    4264             :         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
    4265             :         struct btrfs_free_space *info;
    4266             :         int ret = 0;
    4267             : 
    4268             :         spin_lock(&ctl->tree_lock);
    4269             :         info = tree_search_offset(ctl, offset, 0, 0);
    4270             :         if (!info) {
    4271             :                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
    4272             :                                           1, 0);
    4273             :                 if (!info)
    4274             :                         goto out;
    4275             :         }
    4276             : 
    4277             : have_info:
    4278             :         if (info->bitmap) {
    4279             :                 u64 bit_off, bit_bytes;
    4280             :                 struct rb_node *n;
    4281             :                 struct btrfs_free_space *tmp;
    4282             : 
    4283             :                 bit_off = offset;
    4284             :                 bit_bytes = ctl->unit;
    4285             :                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
    4286             :                 if (!ret) {
    4287             :                         if (bit_off == offset) {
    4288             :                                 ret = 1;
    4289             :                                 goto out;
    4290             :                         } else if (bit_off > offset &&
    4291             :                                    offset + bytes > bit_off) {
    4292             :                                 ret = 1;
    4293             :                                 goto out;
    4294             :                         }
    4295             :                 }
    4296             : 
    4297             :                 n = rb_prev(&info->offset_index);
    4298             :                 while (n) {
    4299             :                         tmp = rb_entry(n, struct btrfs_free_space,
    4300             :                                        offset_index);
    4301             :                         if (tmp->offset + tmp->bytes < offset)
    4302             :                                 break;
    4303             :                         if (offset + bytes < tmp->offset) {
    4304             :                                 n = rb_prev(&tmp->offset_index);
    4305             :                                 continue;
    4306             :                         }
    4307             :                         info = tmp;
    4308             :                         goto have_info;
    4309             :                 }
    4310             : 
    4311             :                 n = rb_next(&info->offset_index);
    4312             :                 while (n) {
    4313             :                         tmp = rb_entry(n, struct btrfs_free_space,
    4314             :                                        offset_index);
    4315             :                         if (offset + bytes < tmp->offset)
    4316             :                                 break;
    4317             :                         if (tmp->offset + tmp->bytes < offset) {
    4318             :                                 n = rb_next(&tmp->offset_index);
    4319             :                                 continue;
    4320             :                         }
    4321             :                         info = tmp;
    4322             :                         goto have_info;
    4323             :                 }
    4324             : 
    4325             :                 ret = 0;
    4326             :                 goto out;
    4327             :         }
    4328             : 
    4329             :         if (info->offset == offset) {
    4330             :                 ret = 1;
    4331             :                 goto out;
    4332             :         }
    4333             : 
    4334             :         if (offset > info->offset && offset < info->offset + info->bytes)
    4335             :                 ret = 1;
    4336             : out:
    4337             :         spin_unlock(&ctl->tree_lock);
    4338             :         return ret;
    4339             : }
    4340             : #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */

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