LCOV - code coverage report
Current view: top level - fs/btrfs - file-item.c (source / functions) Hit Total Coverage
Test: fstests of 6.5.0-rc3-acha @ Mon Jul 31 20:08:06 PDT 2023 Lines: 0 694 0.0 %
Date: 2023-07-31 20:08:07 Functions: 0 18 0.0 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  * Copyright (C) 2007 Oracle.  All rights reserved.
       4             :  */
       5             : 
       6             : #include <linux/bio.h>
       7             : #include <linux/slab.h>
       8             : #include <linux/pagemap.h>
       9             : #include <linux/highmem.h>
      10             : #include <linux/sched/mm.h>
      11             : #include <crypto/hash.h>
      12             : #include "messages.h"
      13             : #include "misc.h"
      14             : #include "ctree.h"
      15             : #include "disk-io.h"
      16             : #include "transaction.h"
      17             : #include "bio.h"
      18             : #include "print-tree.h"
      19             : #include "compression.h"
      20             : #include "fs.h"
      21             : #include "accessors.h"
      22             : #include "file-item.h"
      23             : #include "super.h"
      24             : 
      25             : #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
      26             :                                    sizeof(struct btrfs_item) * 2) / \
      27             :                                   size) - 1))
      28             : 
      29             : #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
      30             :                                        PAGE_SIZE))
      31             : 
      32             : /*
      33             :  * Set inode's size according to filesystem options.
      34             :  *
      35             :  * @inode:      inode we want to update the disk_i_size for
      36             :  * @new_i_size: i_size we want to set to, 0 if we use i_size
      37             :  *
      38             :  * With NO_HOLES set this simply sets the disk_is_size to whatever i_size_read()
      39             :  * returns as it is perfectly fine with a file that has holes without hole file
      40             :  * extent items.
      41             :  *
      42             :  * However without NO_HOLES we need to only return the area that is contiguous
      43             :  * from the 0 offset of the file.  Otherwise we could end up adjust i_size up
      44             :  * to an extent that has a gap in between.
      45             :  *
      46             :  * Finally new_i_size should only be set in the case of truncate where we're not
      47             :  * ready to use i_size_read() as the limiter yet.
      48             :  */
      49           0 : void btrfs_inode_safe_disk_i_size_write(struct btrfs_inode *inode, u64 new_i_size)
      50             : {
      51           0 :         struct btrfs_fs_info *fs_info = inode->root->fs_info;
      52           0 :         u64 start, end, i_size;
      53           0 :         int ret;
      54             : 
      55           0 :         spin_lock(&inode->lock);
      56           0 :         i_size = new_i_size ?: i_size_read(&inode->vfs_inode);
      57           0 :         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
      58           0 :                 inode->disk_i_size = i_size;
      59           0 :                 goto out_unlock;
      60             :         }
      61             : 
      62           0 :         ret = find_contiguous_extent_bit(&inode->file_extent_tree, 0, &start,
      63             :                                          &end, EXTENT_DIRTY);
      64           0 :         if (!ret && start == 0)
      65           0 :                 i_size = min(i_size, end + 1);
      66             :         else
      67             :                 i_size = 0;
      68           0 :         inode->disk_i_size = i_size;
      69           0 : out_unlock:
      70           0 :         spin_unlock(&inode->lock);
      71           0 : }
      72             : 
      73             : /*
      74             :  * Mark range within a file as having a new extent inserted.
      75             :  *
      76             :  * @inode: inode being modified
      77             :  * @start: start file offset of the file extent we've inserted
      78             :  * @len:   logical length of the file extent item
      79             :  *
      80             :  * Call when we are inserting a new file extent where there was none before.
      81             :  * Does not need to call this in the case where we're replacing an existing file
      82             :  * extent, however if not sure it's fine to call this multiple times.
      83             :  *
      84             :  * The start and len must match the file extent item, so thus must be sectorsize
      85             :  * aligned.
      86             :  */
      87           0 : int btrfs_inode_set_file_extent_range(struct btrfs_inode *inode, u64 start,
      88             :                                       u64 len)
      89             : {
      90           0 :         if (len == 0)
      91             :                 return 0;
      92             : 
      93           0 :         ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize));
      94             : 
      95           0 :         if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
      96             :                 return 0;
      97           0 :         return set_extent_bit(&inode->file_extent_tree, start, start + len - 1,
      98             :                               EXTENT_DIRTY, NULL);
      99             : }
     100             : 
     101             : /*
     102             :  * Mark an inode range as not having a backing extent.
     103             :  *
     104             :  * @inode: inode being modified
     105             :  * @start: start file offset of the file extent we've inserted
     106             :  * @len:   logical length of the file extent item
     107             :  *
     108             :  * Called when we drop a file extent, for example when we truncate.  Doesn't
     109             :  * need to be called for cases where we're replacing a file extent, like when
     110             :  * we've COWed a file extent.
     111             :  *
     112             :  * The start and len must match the file extent item, so thus must be sectorsize
     113             :  * aligned.
     114             :  */
     115           0 : int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
     116             :                                         u64 len)
     117             : {
     118           0 :         if (len == 0)
     119             :                 return 0;
     120             : 
     121           0 :         ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize) ||
     122             :                len == (u64)-1);
     123             : 
     124           0 :         if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
     125             :                 return 0;
     126           0 :         return clear_extent_bit(&inode->file_extent_tree, start,
     127             :                                 start + len - 1, EXTENT_DIRTY, NULL);
     128             : }
     129             : 
     130             : static size_t bytes_to_csum_size(const struct btrfs_fs_info *fs_info, u32 bytes)
     131             : {
     132           0 :         ASSERT(IS_ALIGNED(bytes, fs_info->sectorsize));
     133             : 
     134           0 :         return (bytes >> fs_info->sectorsize_bits) * fs_info->csum_size;
     135             : }
     136             : 
     137             : static size_t csum_size_to_bytes(const struct btrfs_fs_info *fs_info, u32 csum_size)
     138             : {
     139           0 :         ASSERT(IS_ALIGNED(csum_size, fs_info->csum_size));
     140             : 
     141           0 :         return (csum_size / fs_info->csum_size) << fs_info->sectorsize_bits;
     142             : }
     143             : 
     144             : static inline u32 max_ordered_sum_bytes(const struct btrfs_fs_info *fs_info)
     145             : {
     146           0 :         u32 max_csum_size = round_down(PAGE_SIZE - sizeof(struct btrfs_ordered_sum),
     147             :                                        fs_info->csum_size);
     148             : 
     149           0 :         return csum_size_to_bytes(fs_info, max_csum_size);
     150             : }
     151             : 
     152             : /*
     153             :  * Calculate the total size needed to allocate for an ordered sum structure
     154             :  * spanning @bytes in the file.
     155             :  */
     156             : static int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info, unsigned long bytes)
     157             : {
     158           0 :         return sizeof(struct btrfs_ordered_sum) + bytes_to_csum_size(fs_info, bytes);
     159             : }
     160             : 
     161           0 : int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
     162             :                              struct btrfs_root *root,
     163             :                              u64 objectid, u64 pos, u64 num_bytes)
     164             : {
     165           0 :         int ret = 0;
     166           0 :         struct btrfs_file_extent_item *item;
     167           0 :         struct btrfs_key file_key;
     168           0 :         struct btrfs_path *path;
     169           0 :         struct extent_buffer *leaf;
     170             : 
     171           0 :         path = btrfs_alloc_path();
     172           0 :         if (!path)
     173             :                 return -ENOMEM;
     174           0 :         file_key.objectid = objectid;
     175           0 :         file_key.offset = pos;
     176           0 :         file_key.type = BTRFS_EXTENT_DATA_KEY;
     177             : 
     178           0 :         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
     179             :                                       sizeof(*item));
     180           0 :         if (ret < 0)
     181           0 :                 goto out;
     182           0 :         BUG_ON(ret); /* Can't happen */
     183           0 :         leaf = path->nodes[0];
     184           0 :         item = btrfs_item_ptr(leaf, path->slots[0],
     185             :                               struct btrfs_file_extent_item);
     186           0 :         btrfs_set_file_extent_disk_bytenr(leaf, item, 0);
     187           0 :         btrfs_set_file_extent_disk_num_bytes(leaf, item, 0);
     188           0 :         btrfs_set_file_extent_offset(leaf, item, 0);
     189           0 :         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
     190           0 :         btrfs_set_file_extent_ram_bytes(leaf, item, num_bytes);
     191           0 :         btrfs_set_file_extent_generation(leaf, item, trans->transid);
     192           0 :         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
     193           0 :         btrfs_set_file_extent_compression(leaf, item, 0);
     194           0 :         btrfs_set_file_extent_encryption(leaf, item, 0);
     195           0 :         btrfs_set_file_extent_other_encoding(leaf, item, 0);
     196             : 
     197           0 :         btrfs_mark_buffer_dirty(leaf);
     198           0 : out:
     199           0 :         btrfs_free_path(path);
     200           0 :         return ret;
     201             : }
     202             : 
     203             : static struct btrfs_csum_item *
     204           0 : btrfs_lookup_csum(struct btrfs_trans_handle *trans,
     205             :                   struct btrfs_root *root,
     206             :                   struct btrfs_path *path,
     207             :                   u64 bytenr, int cow)
     208             : {
     209           0 :         struct btrfs_fs_info *fs_info = root->fs_info;
     210           0 :         int ret;
     211           0 :         struct btrfs_key file_key;
     212           0 :         struct btrfs_key found_key;
     213           0 :         struct btrfs_csum_item *item;
     214           0 :         struct extent_buffer *leaf;
     215           0 :         u64 csum_offset = 0;
     216           0 :         const u32 csum_size = fs_info->csum_size;
     217           0 :         int csums_in_item;
     218             : 
     219           0 :         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
     220           0 :         file_key.offset = bytenr;
     221           0 :         file_key.type = BTRFS_EXTENT_CSUM_KEY;
     222           0 :         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
     223           0 :         if (ret < 0)
     224           0 :                 goto fail;
     225           0 :         leaf = path->nodes[0];
     226           0 :         if (ret > 0) {
     227           0 :                 ret = 1;
     228           0 :                 if (path->slots[0] == 0)
     229           0 :                         goto fail;
     230           0 :                 path->slots[0]--;
     231           0 :                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
     232           0 :                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
     233           0 :                         goto fail;
     234             : 
     235           0 :                 csum_offset = (bytenr - found_key.offset) >>
     236           0 :                                 fs_info->sectorsize_bits;
     237           0 :                 csums_in_item = btrfs_item_size(leaf, path->slots[0]);
     238           0 :                 csums_in_item /= csum_size;
     239             : 
     240           0 :                 if (csum_offset == csums_in_item) {
     241           0 :                         ret = -EFBIG;
     242           0 :                         goto fail;
     243           0 :                 } else if (csum_offset > csums_in_item) {
     244           0 :                         goto fail;
     245             :                 }
     246             :         }
     247           0 :         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
     248           0 :         item = (struct btrfs_csum_item *)((unsigned char *)item +
     249           0 :                                           csum_offset * csum_size);
     250           0 :         return item;
     251             : fail:
     252           0 :         if (ret > 0)
     253             :                 ret = -ENOENT;
     254           0 :         return ERR_PTR(ret);
     255             : }
     256             : 
     257           0 : int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
     258             :                              struct btrfs_root *root,
     259             :                              struct btrfs_path *path, u64 objectid,
     260             :                              u64 offset, int mod)
     261             : {
     262           0 :         struct btrfs_key file_key;
     263           0 :         int ins_len = mod < 0 ? -1 : 0;
     264           0 :         int cow = mod != 0;
     265             : 
     266           0 :         file_key.objectid = objectid;
     267           0 :         file_key.offset = offset;
     268           0 :         file_key.type = BTRFS_EXTENT_DATA_KEY;
     269             : 
     270           0 :         return btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
     271             : }
     272             : 
     273             : /*
     274             :  * Find checksums for logical bytenr range [disk_bytenr, disk_bytenr + len) and
     275             :  * store the result to @dst.
     276             :  *
     277             :  * Return >0 for the number of sectors we found.
     278             :  * Return 0 for the range [disk_bytenr, disk_bytenr + sectorsize) has no csum
     279             :  * for it. Caller may want to try next sector until one range is hit.
     280             :  * Return <0 for fatal error.
     281             :  */
     282           0 : static int search_csum_tree(struct btrfs_fs_info *fs_info,
     283             :                             struct btrfs_path *path, u64 disk_bytenr,
     284             :                             u64 len, u8 *dst)
     285             : {
     286           0 :         struct btrfs_root *csum_root;
     287           0 :         struct btrfs_csum_item *item = NULL;
     288           0 :         struct btrfs_key key;
     289           0 :         const u32 sectorsize = fs_info->sectorsize;
     290           0 :         const u32 csum_size = fs_info->csum_size;
     291           0 :         u32 itemsize;
     292           0 :         int ret;
     293           0 :         u64 csum_start;
     294           0 :         u64 csum_len;
     295             : 
     296           0 :         ASSERT(IS_ALIGNED(disk_bytenr, sectorsize) &&
     297             :                IS_ALIGNED(len, sectorsize));
     298             : 
     299             :         /* Check if the current csum item covers disk_bytenr */
     300           0 :         if (path->nodes[0]) {
     301           0 :                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
     302             :                                       struct btrfs_csum_item);
     303           0 :                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
     304           0 :                 itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
     305             : 
     306           0 :                 csum_start = key.offset;
     307           0 :                 csum_len = (itemsize / csum_size) * sectorsize;
     308             : 
     309           0 :                 if (in_range(disk_bytenr, csum_start, csum_len))
     310           0 :                         goto found;
     311             :         }
     312             : 
     313             :         /* Current item doesn't contain the desired range, search again */
     314           0 :         btrfs_release_path(path);
     315           0 :         csum_root = btrfs_csum_root(fs_info, disk_bytenr);
     316           0 :         item = btrfs_lookup_csum(NULL, csum_root, path, disk_bytenr, 0);
     317           0 :         if (IS_ERR(item)) {
     318           0 :                 ret = PTR_ERR(item);
     319           0 :                 goto out;
     320             :         }
     321           0 :         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
     322           0 :         itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
     323             : 
     324           0 :         csum_start = key.offset;
     325           0 :         csum_len = (itemsize / csum_size) * sectorsize;
     326           0 :         ASSERT(in_range(disk_bytenr, csum_start, csum_len));
     327             : 
     328           0 : found:
     329           0 :         ret = (min(csum_start + csum_len, disk_bytenr + len) -
     330           0 :                    disk_bytenr) >> fs_info->sectorsize_bits;
     331           0 :         read_extent_buffer(path->nodes[0], dst, (unsigned long)item,
     332           0 :                         ret * csum_size);
     333           0 : out:
     334           0 :         if (ret == -ENOENT || ret == -EFBIG)
     335           0 :                 ret = 0;
     336           0 :         return ret;
     337             : }
     338             : 
     339             : /*
     340             :  * Lookup the checksum for the read bio in csum tree.
     341             :  *
     342             :  * Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
     343             :  */
     344           0 : blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio)
     345             : {
     346           0 :         struct btrfs_inode *inode = bbio->inode;
     347           0 :         struct btrfs_fs_info *fs_info = inode->root->fs_info;
     348           0 :         struct bio *bio = &bbio->bio;
     349           0 :         struct btrfs_path *path;
     350           0 :         const u32 sectorsize = fs_info->sectorsize;
     351           0 :         const u32 csum_size = fs_info->csum_size;
     352           0 :         u32 orig_len = bio->bi_iter.bi_size;
     353           0 :         u64 orig_disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT;
     354           0 :         const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits;
     355           0 :         blk_status_t ret = BLK_STS_OK;
     356           0 :         u32 bio_offset = 0;
     357             : 
     358           0 :         if ((inode->flags & BTRFS_INODE_NODATASUM) ||
     359           0 :             test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state))
     360             :                 return BLK_STS_OK;
     361             : 
     362             :         /*
     363             :          * This function is only called for read bio.
     364             :          *
     365             :          * This means two things:
     366             :          * - All our csums should only be in csum tree
     367             :          *   No ordered extents csums, as ordered extents are only for write
     368             :          *   path.
     369             :          * - No need to bother any other info from bvec
     370             :          *   Since we're looking up csums, the only important info is the
     371             :          *   disk_bytenr and the length, which can be extracted from bi_iter
     372             :          *   directly.
     373             :          */
     374           0 :         ASSERT(bio_op(bio) == REQ_OP_READ);
     375           0 :         path = btrfs_alloc_path();
     376           0 :         if (!path)
     377             :                 return BLK_STS_RESOURCE;
     378             : 
     379           0 :         if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
     380           0 :                 bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS);
     381           0 :                 if (!bbio->csum) {
     382           0 :                         btrfs_free_path(path);
     383           0 :                         return BLK_STS_RESOURCE;
     384             :                 }
     385             :         } else {
     386           0 :                 bbio->csum = bbio->csum_inline;
     387             :         }
     388             : 
     389             :         /*
     390             :          * If requested number of sectors is larger than one leaf can contain,
     391             :          * kick the readahead for csum tree.
     392             :          */
     393           0 :         if (nblocks > fs_info->csums_per_leaf)
     394           0 :                 path->reada = READA_FORWARD;
     395             : 
     396             :         /*
     397             :          * the free space stuff is only read when it hasn't been
     398             :          * updated in the current transaction.  So, we can safely
     399             :          * read from the commit root and sidestep a nasty deadlock
     400             :          * between reading the free space cache and updating the csum tree.
     401             :          */
     402           0 :         if (btrfs_is_free_space_inode(inode)) {
     403           0 :                 path->search_commit_root = 1;
     404           0 :                 path->skip_locking = 1;
     405             :         }
     406             : 
     407           0 :         while (bio_offset < orig_len) {
     408           0 :                 int count;
     409           0 :                 u64 cur_disk_bytenr = orig_disk_bytenr + bio_offset;
     410           0 :                 u8 *csum_dst = bbio->csum +
     411           0 :                         (bio_offset >> fs_info->sectorsize_bits) * csum_size;
     412             : 
     413           0 :                 count = search_csum_tree(fs_info, path, cur_disk_bytenr,
     414           0 :                                          orig_len - bio_offset, csum_dst);
     415           0 :                 if (count < 0) {
     416           0 :                         ret = errno_to_blk_status(count);
     417           0 :                         if (bbio->csum != bbio->csum_inline)
     418           0 :                                 kfree(bbio->csum);
     419           0 :                         bbio->csum = NULL;
     420           0 :                         break;
     421             :                 }
     422             : 
     423             :                 /*
     424             :                  * We didn't find a csum for this range.  We need to make sure
     425             :                  * we complain loudly about this, because we are not NODATASUM.
     426             :                  *
     427             :                  * However for the DATA_RELOC inode we could potentially be
     428             :                  * relocating data extents for a NODATASUM inode, so the inode
     429             :                  * itself won't be marked with NODATASUM, but the extent we're
     430             :                  * copying is in fact NODATASUM.  If we don't find a csum we
     431             :                  * assume this is the case.
     432             :                  */
     433           0 :                 if (count == 0) {
     434           0 :                         memset(csum_dst, 0, csum_size);
     435           0 :                         count = 1;
     436             : 
     437           0 :                         if (inode->root->root_key.objectid ==
     438             :                             BTRFS_DATA_RELOC_TREE_OBJECTID) {
     439           0 :                                 u64 file_offset = bbio->file_offset + bio_offset;
     440             : 
     441           0 :                                 set_extent_bit(&inode->io_tree, file_offset,
     442           0 :                                                file_offset + sectorsize - 1,
     443             :                                                EXTENT_NODATASUM, NULL);
     444             :                         } else {
     445           0 :                                 btrfs_warn_rl(fs_info,
     446             :                         "csum hole found for disk bytenr range [%llu, %llu)",
     447             :                                 cur_disk_bytenr, cur_disk_bytenr + sectorsize);
     448             :                         }
     449             :                 }
     450           0 :                 bio_offset += count * sectorsize;
     451             :         }
     452             : 
     453           0 :         btrfs_free_path(path);
     454           0 :         return ret;
     455             : }
     456             : 
     457           0 : int btrfs_lookup_csums_list(struct btrfs_root *root, u64 start, u64 end,
     458             :                             struct list_head *list, int search_commit,
     459             :                             bool nowait)
     460             : {
     461           0 :         struct btrfs_fs_info *fs_info = root->fs_info;
     462           0 :         struct btrfs_key key;
     463           0 :         struct btrfs_path *path;
     464           0 :         struct extent_buffer *leaf;
     465           0 :         struct btrfs_ordered_sum *sums;
     466           0 :         struct btrfs_csum_item *item;
     467           0 :         LIST_HEAD(tmplist);
     468           0 :         int ret;
     469             : 
     470           0 :         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
     471             :                IS_ALIGNED(end + 1, fs_info->sectorsize));
     472             : 
     473           0 :         path = btrfs_alloc_path();
     474           0 :         if (!path)
     475             :                 return -ENOMEM;
     476             : 
     477           0 :         path->nowait = nowait;
     478           0 :         if (search_commit) {
     479           0 :                 path->skip_locking = 1;
     480           0 :                 path->reada = READA_FORWARD;
     481           0 :                 path->search_commit_root = 1;
     482             :         }
     483             : 
     484           0 :         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
     485           0 :         key.offset = start;
     486           0 :         key.type = BTRFS_EXTENT_CSUM_KEY;
     487             : 
     488           0 :         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
     489           0 :         if (ret < 0)
     490           0 :                 goto fail;
     491           0 :         if (ret > 0 && path->slots[0] > 0) {
     492           0 :                 leaf = path->nodes[0];
     493           0 :                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
     494             : 
     495             :                 /*
     496             :                  * There are two cases we can hit here for the previous csum
     497             :                  * item:
     498             :                  *
     499             :                  *              |<- search range ->|
     500             :                  *      |<- csum item ->|
     501             :                  *
     502             :                  * Or
     503             :                  *                              |<- search range ->|
     504             :                  *      |<- csum item ->|
     505             :                  *
     506             :                  * Check if the previous csum item covers the leading part of
     507             :                  * the search range.  If so we have to start from previous csum
     508             :                  * item.
     509             :                  */
     510           0 :                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
     511           0 :                     key.type == BTRFS_EXTENT_CSUM_KEY) {
     512           0 :                         if (bytes_to_csum_size(fs_info, start - key.offset) <
     513           0 :                             btrfs_item_size(leaf, path->slots[0] - 1))
     514           0 :                                 path->slots[0]--;
     515             :                 }
     516             :         }
     517             : 
     518           0 :         while (start <= end) {
     519           0 :                 u64 csum_end;
     520             : 
     521           0 :                 leaf = path->nodes[0];
     522           0 :                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
     523           0 :                         ret = btrfs_next_leaf(root, path);
     524           0 :                         if (ret < 0)
     525           0 :                                 goto fail;
     526           0 :                         if (ret > 0)
     527             :                                 break;
     528           0 :                         leaf = path->nodes[0];
     529             :                 }
     530             : 
     531           0 :                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
     532           0 :                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
     533           0 :                     key.type != BTRFS_EXTENT_CSUM_KEY ||
     534           0 :                     key.offset > end)
     535             :                         break;
     536             : 
     537           0 :                 if (key.offset > start)
     538             :                         start = key.offset;
     539             : 
     540           0 :                 csum_end = key.offset + csum_size_to_bytes(fs_info,
     541             :                                         btrfs_item_size(leaf, path->slots[0]));
     542           0 :                 if (csum_end <= start) {
     543           0 :                         path->slots[0]++;
     544           0 :                         continue;
     545             :                 }
     546             : 
     547           0 :                 csum_end = min(csum_end, end + 1);
     548           0 :                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
     549             :                                       struct btrfs_csum_item);
     550           0 :                 while (start < csum_end) {
     551           0 :                         unsigned long offset;
     552           0 :                         size_t size;
     553             : 
     554           0 :                         size = min_t(size_t, csum_end - start,
     555             :                                      max_ordered_sum_bytes(fs_info));
     556           0 :                         sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
     557             :                                        GFP_NOFS);
     558           0 :                         if (!sums) {
     559           0 :                                 ret = -ENOMEM;
     560           0 :                                 goto fail;
     561             :                         }
     562             : 
     563           0 :                         sums->logical = start;
     564           0 :                         sums->len = size;
     565             : 
     566           0 :                         offset = bytes_to_csum_size(fs_info, start - key.offset);
     567             : 
     568           0 :                         read_extent_buffer(path->nodes[0],
     569           0 :                                            sums->sums,
     570             :                                            ((unsigned long)item) + offset,
     571             :                                            bytes_to_csum_size(fs_info, size));
     572             : 
     573           0 :                         start += size;
     574           0 :                         list_add_tail(&sums->list, &tmplist);
     575             :                 }
     576           0 :                 path->slots[0]++;
     577             :         }
     578             :         ret = 0;
     579           0 : fail:
     580           0 :         while (ret < 0 && !list_empty(&tmplist)) {
     581           0 :                 sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
     582           0 :                 list_del(&sums->list);
     583           0 :                 kfree(sums);
     584             :         }
     585           0 :         list_splice_tail(&tmplist, list);
     586             : 
     587           0 :         btrfs_free_path(path);
     588           0 :         return ret;
     589             : }
     590             : 
     591             : /*
     592             :  * Do the same work as btrfs_lookup_csums_list(), the difference is in how
     593             :  * we return the result.
     594             :  *
     595             :  * This version will set the corresponding bits in @csum_bitmap to represent
     596             :  * that there is a csum found.
     597             :  * Each bit represents a sector. Thus caller should ensure @csum_buf passed
     598             :  * in is large enough to contain all csums.
     599             :  */
     600           0 : int btrfs_lookup_csums_bitmap(struct btrfs_root *root, u64 start, u64 end,
     601             :                               u8 *csum_buf, unsigned long *csum_bitmap,
     602             :                               bool search_commit)
     603             : {
     604           0 :         struct btrfs_fs_info *fs_info = root->fs_info;
     605           0 :         struct btrfs_key key;
     606           0 :         struct btrfs_path *path;
     607           0 :         struct extent_buffer *leaf;
     608           0 :         struct btrfs_csum_item *item;
     609           0 :         const u64 orig_start = start;
     610           0 :         int ret;
     611             : 
     612           0 :         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
     613             :                IS_ALIGNED(end + 1, fs_info->sectorsize));
     614             : 
     615           0 :         path = btrfs_alloc_path();
     616           0 :         if (!path)
     617             :                 return -ENOMEM;
     618             : 
     619           0 :         if (search_commit) {
     620           0 :                 path->skip_locking = 1;
     621           0 :                 path->reada = READA_FORWARD;
     622           0 :                 path->search_commit_root = 1;
     623             :         }
     624             : 
     625           0 :         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
     626           0 :         key.type = BTRFS_EXTENT_CSUM_KEY;
     627           0 :         key.offset = start;
     628             : 
     629           0 :         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
     630           0 :         if (ret < 0)
     631           0 :                 goto fail;
     632           0 :         if (ret > 0 && path->slots[0] > 0) {
     633           0 :                 leaf = path->nodes[0];
     634           0 :                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
     635             : 
     636             :                 /*
     637             :                  * There are two cases we can hit here for the previous csum
     638             :                  * item:
     639             :                  *
     640             :                  *              |<- search range ->|
     641             :                  *      |<- csum item ->|
     642             :                  *
     643             :                  * Or
     644             :                  *                              |<- search range ->|
     645             :                  *      |<- csum item ->|
     646             :                  *
     647             :                  * Check if the previous csum item covers the leading part of
     648             :                  * the search range.  If so we have to start from previous csum
     649             :                  * item.
     650             :                  */
     651           0 :                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
     652           0 :                     key.type == BTRFS_EXTENT_CSUM_KEY) {
     653           0 :                         if (bytes_to_csum_size(fs_info, start - key.offset) <
     654           0 :                             btrfs_item_size(leaf, path->slots[0] - 1))
     655           0 :                                 path->slots[0]--;
     656             :                 }
     657             :         }
     658             : 
     659           0 :         while (start <= end) {
     660           0 :                 u64 csum_end;
     661             : 
     662           0 :                 leaf = path->nodes[0];
     663           0 :                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
     664           0 :                         ret = btrfs_next_leaf(root, path);
     665           0 :                         if (ret < 0)
     666           0 :                                 goto fail;
     667           0 :                         if (ret > 0)
     668             :                                 break;
     669           0 :                         leaf = path->nodes[0];
     670             :                 }
     671             : 
     672           0 :                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
     673           0 :                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
     674           0 :                     key.type != BTRFS_EXTENT_CSUM_KEY ||
     675           0 :                     key.offset > end)
     676             :                         break;
     677             : 
     678           0 :                 if (key.offset > start)
     679             :                         start = key.offset;
     680             : 
     681           0 :                 csum_end = key.offset + csum_size_to_bytes(fs_info,
     682             :                                         btrfs_item_size(leaf, path->slots[0]));
     683           0 :                 if (csum_end <= start) {
     684           0 :                         path->slots[0]++;
     685           0 :                         continue;
     686             :                 }
     687             : 
     688           0 :                 csum_end = min(csum_end, end + 1);
     689           0 :                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
     690             :                                       struct btrfs_csum_item);
     691           0 :                 while (start < csum_end) {
     692           0 :                         unsigned long offset;
     693           0 :                         size_t size;
     694           0 :                         u8 *csum_dest = csum_buf + bytes_to_csum_size(fs_info,
     695             :                                                 start - orig_start);
     696             : 
     697           0 :                         size = min_t(size_t, csum_end - start, end + 1 - start);
     698             : 
     699           0 :                         offset = bytes_to_csum_size(fs_info, start - key.offset);
     700             : 
     701           0 :                         read_extent_buffer(path->nodes[0], csum_dest,
     702             :                                            ((unsigned long)item) + offset,
     703             :                                            bytes_to_csum_size(fs_info, size));
     704             : 
     705           0 :                         bitmap_set(csum_bitmap,
     706           0 :                                 (start - orig_start) >> fs_info->sectorsize_bits,
     707           0 :                                 size >> fs_info->sectorsize_bits);
     708             : 
     709           0 :                         start += size;
     710             :                 }
     711           0 :                 path->slots[0]++;
     712             :         }
     713             :         ret = 0;
     714           0 : fail:
     715           0 :         btrfs_free_path(path);
     716           0 :         return ret;
     717             : }
     718             : 
     719             : /*
     720             :  * Calculate checksums of the data contained inside a bio.
     721             :  */
     722           0 : blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
     723             : {
     724           0 :         struct btrfs_ordered_extent *ordered = bbio->ordered;
     725           0 :         struct btrfs_inode *inode = bbio->inode;
     726           0 :         struct btrfs_fs_info *fs_info = inode->root->fs_info;
     727           0 :         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
     728           0 :         struct bio *bio = &bbio->bio;
     729           0 :         struct btrfs_ordered_sum *sums;
     730           0 :         char *data;
     731           0 :         struct bvec_iter iter;
     732           0 :         struct bio_vec bvec;
     733           0 :         int index;
     734           0 :         unsigned int blockcount;
     735           0 :         int i;
     736           0 :         unsigned nofs_flag;
     737             : 
     738           0 :         nofs_flag = memalloc_nofs_save();
     739           0 :         sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
     740             :                        GFP_KERNEL);
     741           0 :         memalloc_nofs_restore(nofs_flag);
     742             : 
     743           0 :         if (!sums)
     744             :                 return BLK_STS_RESOURCE;
     745             : 
     746           0 :         sums->len = bio->bi_iter.bi_size;
     747           0 :         INIT_LIST_HEAD(&sums->list);
     748             : 
     749           0 :         sums->logical = bio->bi_iter.bi_sector << SECTOR_SHIFT;
     750           0 :         index = 0;
     751             : 
     752           0 :         shash->tfm = fs_info->csum_shash;
     753             : 
     754           0 :         bio_for_each_segment(bvec, bio, iter) {
     755           0 :                 blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
     756             :                                                  bvec.bv_len + fs_info->sectorsize
     757             :                                                  - 1);
     758             : 
     759           0 :                 for (i = 0; i < blockcount; i++) {
     760           0 :                         data = bvec_kmap_local(&bvec);
     761           0 :                         crypto_shash_digest(shash,
     762           0 :                                             data + (i * fs_info->sectorsize),
     763             :                                             fs_info->sectorsize,
     764           0 :                                             sums->sums + index);
     765           0 :                         kunmap_local(data);
     766           0 :                         index += fs_info->csum_size;
     767             :                 }
     768             : 
     769             :         }
     770             : 
     771           0 :         bbio->sums = sums;
     772           0 :         btrfs_add_ordered_sum(ordered, sums);
     773           0 :         return 0;
     774             : }
     775             : 
     776             : /*
     777             :  * Nodatasum I/O on zoned file systems still requires an btrfs_ordered_sum to
     778             :  * record the updated logical address on Zone Append completion.
     779             :  * Allocate just the structure with an empty sums array here for that case.
     780             :  */
     781           0 : blk_status_t btrfs_alloc_dummy_sum(struct btrfs_bio *bbio)
     782             : {
     783           0 :         bbio->sums = kmalloc(sizeof(*bbio->sums), GFP_NOFS);
     784           0 :         if (!bbio->sums)
     785             :                 return BLK_STS_RESOURCE;
     786           0 :         bbio->sums->len = bbio->bio.bi_iter.bi_size;
     787           0 :         bbio->sums->logical = bbio->bio.bi_iter.bi_sector << SECTOR_SHIFT;
     788           0 :         btrfs_add_ordered_sum(bbio->ordered, bbio->sums);
     789           0 :         return 0;
     790             : }
     791             : 
     792             : /*
     793             :  * Remove one checksum overlapping a range.
     794             :  *
     795             :  * This expects the key to describe the csum pointed to by the path, and it
     796             :  * expects the csum to overlap the range [bytenr, len]
     797             :  *
     798             :  * The csum should not be entirely contained in the range and the range should
     799             :  * not be entirely contained in the csum.
     800             :  *
     801             :  * This calls btrfs_truncate_item with the correct args based on the overlap,
     802             :  * and fixes up the key as required.
     803             :  */
     804           0 : static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
     805             :                                        struct btrfs_path *path,
     806             :                                        struct btrfs_key *key,
     807             :                                        u64 bytenr, u64 len)
     808             : {
     809           0 :         struct extent_buffer *leaf;
     810           0 :         const u32 csum_size = fs_info->csum_size;
     811           0 :         u64 csum_end;
     812           0 :         u64 end_byte = bytenr + len;
     813           0 :         u32 blocksize_bits = fs_info->sectorsize_bits;
     814             : 
     815           0 :         leaf = path->nodes[0];
     816           0 :         csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
     817           0 :         csum_end <<= blocksize_bits;
     818           0 :         csum_end += key->offset;
     819             : 
     820           0 :         if (key->offset < bytenr && csum_end <= end_byte) {
     821             :                 /*
     822             :                  *         [ bytenr - len ]
     823             :                  *         [   ]
     824             :                  *   [csum     ]
     825             :                  *   A simple truncate off the end of the item
     826             :                  */
     827           0 :                 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
     828           0 :                 new_size *= csum_size;
     829           0 :                 btrfs_truncate_item(path, new_size, 1);
     830           0 :         } else if (key->offset >= bytenr && csum_end > end_byte &&
     831           0 :                    end_byte > key->offset) {
     832             :                 /*
     833             :                  *         [ bytenr - len ]
     834             :                  *                 [ ]
     835             :                  *                 [csum     ]
     836             :                  * we need to truncate from the beginning of the csum
     837             :                  */
     838           0 :                 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
     839           0 :                 new_size *= csum_size;
     840             : 
     841           0 :                 btrfs_truncate_item(path, new_size, 0);
     842             : 
     843           0 :                 key->offset = end_byte;
     844           0 :                 btrfs_set_item_key_safe(fs_info, path, key);
     845             :         } else {
     846           0 :                 BUG();
     847             :         }
     848           0 : }
     849             : 
     850             : /*
     851             :  * Delete the csum items from the csum tree for a given range of bytes.
     852             :  */
     853           0 : int btrfs_del_csums(struct btrfs_trans_handle *trans,
     854             :                     struct btrfs_root *root, u64 bytenr, u64 len)
     855             : {
     856           0 :         struct btrfs_fs_info *fs_info = trans->fs_info;
     857           0 :         struct btrfs_path *path;
     858           0 :         struct btrfs_key key;
     859           0 :         u64 end_byte = bytenr + len;
     860           0 :         u64 csum_end;
     861           0 :         struct extent_buffer *leaf;
     862           0 :         int ret = 0;
     863           0 :         const u32 csum_size = fs_info->csum_size;
     864           0 :         u32 blocksize_bits = fs_info->sectorsize_bits;
     865             : 
     866           0 :         ASSERT(root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID ||
     867             :                root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
     868             : 
     869           0 :         path = btrfs_alloc_path();
     870           0 :         if (!path)
     871             :                 return -ENOMEM;
     872             : 
     873           0 :         while (1) {
     874           0 :                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
     875           0 :                 key.offset = end_byte - 1;
     876           0 :                 key.type = BTRFS_EXTENT_CSUM_KEY;
     877             : 
     878           0 :                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
     879           0 :                 if (ret > 0) {
     880           0 :                         ret = 0;
     881           0 :                         if (path->slots[0] == 0)
     882             :                                 break;
     883           0 :                         path->slots[0]--;
     884           0 :                 } else if (ret < 0) {
     885             :                         break;
     886             :                 }
     887             : 
     888           0 :                 leaf = path->nodes[0];
     889           0 :                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
     890             : 
     891           0 :                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
     892           0 :                     key.type != BTRFS_EXTENT_CSUM_KEY) {
     893             :                         break;
     894             :                 }
     895             : 
     896           0 :                 if (key.offset >= end_byte)
     897             :                         break;
     898             : 
     899           0 :                 csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
     900           0 :                 csum_end <<= blocksize_bits;
     901           0 :                 csum_end += key.offset;
     902             : 
     903             :                 /* this csum ends before we start, we're done */
     904           0 :                 if (csum_end <= bytenr)
     905             :                         break;
     906             : 
     907             :                 /* delete the entire item, it is inside our range */
     908           0 :                 if (key.offset >= bytenr && csum_end <= end_byte) {
     909           0 :                         int del_nr = 1;
     910             : 
     911             :                         /*
     912             :                          * Check how many csum items preceding this one in this
     913             :                          * leaf correspond to our range and then delete them all
     914             :                          * at once.
     915             :                          */
     916           0 :                         if (key.offset > bytenr && path->slots[0] > 0) {
     917           0 :                                 int slot = path->slots[0] - 1;
     918             : 
     919           0 :                                 while (slot >= 0) {
     920           0 :                                         struct btrfs_key pk;
     921             : 
     922           0 :                                         btrfs_item_key_to_cpu(leaf, &pk, slot);
     923           0 :                                         if (pk.offset < bytenr ||
     924           0 :                                             pk.type != BTRFS_EXTENT_CSUM_KEY ||
     925           0 :                                             pk.objectid !=
     926             :                                             BTRFS_EXTENT_CSUM_OBJECTID)
     927             :                                                 break;
     928           0 :                                         path->slots[0] = slot;
     929           0 :                                         del_nr++;
     930           0 :                                         key.offset = pk.offset;
     931           0 :                                         slot--;
     932             :                                 }
     933             :                         }
     934           0 :                         ret = btrfs_del_items(trans, root, path,
     935             :                                               path->slots[0], del_nr);
     936           0 :                         if (ret)
     937             :                                 break;
     938           0 :                         if (key.offset == bytenr)
     939             :                                 break;
     940           0 :                 } else if (key.offset < bytenr && csum_end > end_byte) {
     941           0 :                         unsigned long offset;
     942           0 :                         unsigned long shift_len;
     943           0 :                         unsigned long item_offset;
     944             :                         /*
     945             :                          *        [ bytenr - len ]
     946             :                          *     [csum                ]
     947             :                          *
     948             :                          * Our bytes are in the middle of the csum,
     949             :                          * we need to split this item and insert a new one.
     950             :                          *
     951             :                          * But we can't drop the path because the
     952             :                          * csum could change, get removed, extended etc.
     953             :                          *
     954             :                          * The trick here is the max size of a csum item leaves
     955             :                          * enough room in the tree block for a single
     956             :                          * item header.  So, we split the item in place,
     957             :                          * adding a new header pointing to the existing
     958             :                          * bytes.  Then we loop around again and we have
     959             :                          * a nicely formed csum item that we can neatly
     960             :                          * truncate.
     961             :                          */
     962           0 :                         offset = (bytenr - key.offset) >> blocksize_bits;
     963           0 :                         offset *= csum_size;
     964             : 
     965           0 :                         shift_len = (len >> blocksize_bits) * csum_size;
     966             : 
     967           0 :                         item_offset = btrfs_item_ptr_offset(leaf,
     968             :                                                             path->slots[0]);
     969             : 
     970           0 :                         memzero_extent_buffer(leaf, item_offset + offset,
     971             :                                              shift_len);
     972           0 :                         key.offset = bytenr;
     973             : 
     974             :                         /*
     975             :                          * btrfs_split_item returns -EAGAIN when the
     976             :                          * item changed size or key
     977             :                          */
     978           0 :                         ret = btrfs_split_item(trans, root, path, &key, offset);
     979           0 :                         if (ret && ret != -EAGAIN) {
     980           0 :                                 btrfs_abort_transaction(trans, ret);
     981           0 :                                 break;
     982             :                         }
     983           0 :                         ret = 0;
     984             : 
     985           0 :                         key.offset = end_byte - 1;
     986             :                 } else {
     987           0 :                         truncate_one_csum(fs_info, path, &key, bytenr, len);
     988           0 :                         if (key.offset < bytenr)
     989             :                                 break;
     990             :                 }
     991           0 :                 btrfs_release_path(path);
     992             :         }
     993           0 :         btrfs_free_path(path);
     994           0 :         return ret;
     995             : }
     996             : 
     997           0 : static int find_next_csum_offset(struct btrfs_root *root,
     998             :                                  struct btrfs_path *path,
     999             :                                  u64 *next_offset)
    1000             : {
    1001           0 :         const u32 nritems = btrfs_header_nritems(path->nodes[0]);
    1002           0 :         struct btrfs_key found_key;
    1003           0 :         int slot = path->slots[0] + 1;
    1004           0 :         int ret;
    1005             : 
    1006           0 :         if (nritems == 0 || slot >= nritems) {
    1007           0 :                 ret = btrfs_next_leaf(root, path);
    1008           0 :                 if (ret < 0) {
    1009             :                         return ret;
    1010           0 :                 } else if (ret > 0) {
    1011           0 :                         *next_offset = (u64)-1;
    1012           0 :                         return 0;
    1013             :                 }
    1014           0 :                 slot = path->slots[0];
    1015             :         }
    1016             : 
    1017           0 :         btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
    1018             : 
    1019           0 :         if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
    1020           0 :             found_key.type != BTRFS_EXTENT_CSUM_KEY)
    1021           0 :                 *next_offset = (u64)-1;
    1022             :         else
    1023           0 :                 *next_offset = found_key.offset;
    1024             : 
    1025             :         return 0;
    1026             : }
    1027             : 
    1028           0 : int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
    1029             :                            struct btrfs_root *root,
    1030             :                            struct btrfs_ordered_sum *sums)
    1031             : {
    1032           0 :         struct btrfs_fs_info *fs_info = root->fs_info;
    1033           0 :         struct btrfs_key file_key;
    1034           0 :         struct btrfs_key found_key;
    1035           0 :         struct btrfs_path *path;
    1036           0 :         struct btrfs_csum_item *item;
    1037           0 :         struct btrfs_csum_item *item_end;
    1038           0 :         struct extent_buffer *leaf = NULL;
    1039           0 :         u64 next_offset;
    1040           0 :         u64 total_bytes = 0;
    1041           0 :         u64 csum_offset;
    1042           0 :         u64 bytenr;
    1043           0 :         u32 ins_size;
    1044           0 :         int index = 0;
    1045           0 :         int found_next;
    1046           0 :         int ret;
    1047           0 :         const u32 csum_size = fs_info->csum_size;
    1048             : 
    1049           0 :         path = btrfs_alloc_path();
    1050           0 :         if (!path)
    1051             :                 return -ENOMEM;
    1052           0 : again:
    1053           0 :         next_offset = (u64)-1;
    1054           0 :         found_next = 0;
    1055           0 :         bytenr = sums->logical + total_bytes;
    1056           0 :         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
    1057           0 :         file_key.offset = bytenr;
    1058           0 :         file_key.type = BTRFS_EXTENT_CSUM_KEY;
    1059             : 
    1060           0 :         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
    1061           0 :         if (!IS_ERR(item)) {
    1062           0 :                 ret = 0;
    1063           0 :                 leaf = path->nodes[0];
    1064           0 :                 item_end = btrfs_item_ptr(leaf, path->slots[0],
    1065             :                                           struct btrfs_csum_item);
    1066           0 :                 item_end = (struct btrfs_csum_item *)((char *)item_end +
    1067           0 :                            btrfs_item_size(leaf, path->slots[0]));
    1068           0 :                 goto found;
    1069             :         }
    1070           0 :         ret = PTR_ERR(item);
    1071           0 :         if (ret != -EFBIG && ret != -ENOENT)
    1072           0 :                 goto out;
    1073             : 
    1074           0 :         if (ret == -EFBIG) {
    1075           0 :                 u32 item_size;
    1076             :                 /* we found one, but it isn't big enough yet */
    1077           0 :                 leaf = path->nodes[0];
    1078           0 :                 item_size = btrfs_item_size(leaf, path->slots[0]);
    1079           0 :                 if ((item_size / csum_size) >=
    1080           0 :                     MAX_CSUM_ITEMS(fs_info, csum_size)) {
    1081             :                         /* already at max size, make a new one */
    1082           0 :                         goto insert;
    1083             :                 }
    1084             :         } else {
    1085             :                 /* We didn't find a csum item, insert one. */
    1086           0 :                 ret = find_next_csum_offset(root, path, &next_offset);
    1087           0 :                 if (ret < 0)
    1088           0 :                         goto out;
    1089           0 :                 found_next = 1;
    1090           0 :                 goto insert;
    1091             :         }
    1092             : 
    1093             :         /*
    1094             :          * At this point, we know the tree has a checksum item that ends at an
    1095             :          * offset matching the start of the checksum range we want to insert.
    1096             :          * We try to extend that item as much as possible and then add as many
    1097             :          * checksums to it as they fit.
    1098             :          *
    1099             :          * First check if the leaf has enough free space for at least one
    1100             :          * checksum. If it has go directly to the item extension code, otherwise
    1101             :          * release the path and do a search for insertion before the extension.
    1102             :          */
    1103           0 :         if (btrfs_leaf_free_space(leaf) >= csum_size) {
    1104           0 :                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
    1105           0 :                 csum_offset = (bytenr - found_key.offset) >>
    1106           0 :                         fs_info->sectorsize_bits;
    1107           0 :                 goto extend_csum;
    1108             :         }
    1109             : 
    1110           0 :         btrfs_release_path(path);
    1111           0 :         path->search_for_extension = 1;
    1112           0 :         ret = btrfs_search_slot(trans, root, &file_key, path,
    1113             :                                 csum_size, 1);
    1114           0 :         path->search_for_extension = 0;
    1115           0 :         if (ret < 0)
    1116           0 :                 goto out;
    1117             : 
    1118           0 :         if (ret > 0) {
    1119           0 :                 if (path->slots[0] == 0)
    1120           0 :                         goto insert;
    1121           0 :                 path->slots[0]--;
    1122             :         }
    1123             : 
    1124           0 :         leaf = path->nodes[0];
    1125           0 :         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
    1126           0 :         csum_offset = (bytenr - found_key.offset) >> fs_info->sectorsize_bits;
    1127             : 
    1128           0 :         if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
    1129           0 :             found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
    1130           0 :             csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
    1131           0 :                 goto insert;
    1132             :         }
    1133             : 
    1134           0 : extend_csum:
    1135           0 :         if (csum_offset == btrfs_item_size(leaf, path->slots[0]) /
    1136             :             csum_size) {
    1137           0 :                 int extend_nr;
    1138           0 :                 u64 tmp;
    1139           0 :                 u32 diff;
    1140             : 
    1141           0 :                 tmp = sums->len - total_bytes;
    1142           0 :                 tmp >>= fs_info->sectorsize_bits;
    1143           0 :                 WARN_ON(tmp < 1);
    1144           0 :                 extend_nr = max_t(int, 1, tmp);
    1145             : 
    1146             :                 /*
    1147             :                  * A log tree can already have checksum items with a subset of
    1148             :                  * the checksums we are trying to log. This can happen after
    1149             :                  * doing a sequence of partial writes into prealloc extents and
    1150             :                  * fsyncs in between, with a full fsync logging a larger subrange
    1151             :                  * of an extent for which a previous fast fsync logged a smaller
    1152             :                  * subrange. And this happens in particular due to merging file
    1153             :                  * extent items when we complete an ordered extent for a range
    1154             :                  * covered by a prealloc extent - this is done at
    1155             :                  * btrfs_mark_extent_written().
    1156             :                  *
    1157             :                  * So if we try to extend the previous checksum item, which has
    1158             :                  * a range that ends at the start of the range we want to insert,
    1159             :                  * make sure we don't extend beyond the start offset of the next
    1160             :                  * checksum item. If we are at the last item in the leaf, then
    1161             :                  * forget the optimization of extending and add a new checksum
    1162             :                  * item - it is not worth the complexity of releasing the path,
    1163             :                  * getting the first key for the next leaf, repeat the btree
    1164             :                  * search, etc, because log trees are temporary anyway and it
    1165             :                  * would only save a few bytes of leaf space.
    1166             :                  */
    1167           0 :                 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
    1168           0 :                         if (path->slots[0] + 1 >=
    1169           0 :                             btrfs_header_nritems(path->nodes[0])) {
    1170           0 :                                 ret = find_next_csum_offset(root, path, &next_offset);
    1171           0 :                                 if (ret < 0)
    1172           0 :                                         goto out;
    1173           0 :                                 found_next = 1;
    1174           0 :                                 goto insert;
    1175             :                         }
    1176             : 
    1177           0 :                         ret = find_next_csum_offset(root, path, &next_offset);
    1178           0 :                         if (ret < 0)
    1179           0 :                                 goto out;
    1180             : 
    1181           0 :                         tmp = (next_offset - bytenr) >> fs_info->sectorsize_bits;
    1182           0 :                         if (tmp <= INT_MAX)
    1183           0 :                                 extend_nr = min_t(int, extend_nr, tmp);
    1184             :                 }
    1185             : 
    1186           0 :                 diff = (csum_offset + extend_nr) * csum_size;
    1187           0 :                 diff = min(diff,
    1188             :                            MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
    1189             : 
    1190           0 :                 diff = diff - btrfs_item_size(leaf, path->slots[0]);
    1191           0 :                 diff = min_t(u32, btrfs_leaf_free_space(leaf), diff);
    1192           0 :                 diff /= csum_size;
    1193           0 :                 diff *= csum_size;
    1194             : 
    1195           0 :                 btrfs_extend_item(path, diff);
    1196           0 :                 ret = 0;
    1197           0 :                 goto csum;
    1198             :         }
    1199             : 
    1200           0 : insert:
    1201           0 :         btrfs_release_path(path);
    1202           0 :         csum_offset = 0;
    1203           0 :         if (found_next) {
    1204           0 :                 u64 tmp;
    1205             : 
    1206           0 :                 tmp = sums->len - total_bytes;
    1207           0 :                 tmp >>= fs_info->sectorsize_bits;
    1208           0 :                 tmp = min(tmp, (next_offset - file_key.offset) >>
    1209             :                                          fs_info->sectorsize_bits);
    1210             : 
    1211           0 :                 tmp = max_t(u64, 1, tmp);
    1212           0 :                 tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
    1213           0 :                 ins_size = csum_size * tmp;
    1214             :         } else {
    1215             :                 ins_size = csum_size;
    1216             :         }
    1217           0 :         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
    1218             :                                       ins_size);
    1219           0 :         if (ret < 0)
    1220           0 :                 goto out;
    1221           0 :         if (WARN_ON(ret != 0))
    1222           0 :                 goto out;
    1223           0 :         leaf = path->nodes[0];
    1224           0 : csum:
    1225           0 :         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
    1226           0 :         item_end = (struct btrfs_csum_item *)((unsigned char *)item +
    1227           0 :                                       btrfs_item_size(leaf, path->slots[0]));
    1228           0 :         item = (struct btrfs_csum_item *)((unsigned char *)item +
    1229           0 :                                           csum_offset * csum_size);
    1230           0 : found:
    1231           0 :         ins_size = (u32)(sums->len - total_bytes) >> fs_info->sectorsize_bits;
    1232           0 :         ins_size *= csum_size;
    1233           0 :         ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
    1234             :                               ins_size);
    1235           0 :         write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
    1236             :                             ins_size);
    1237             : 
    1238           0 :         index += ins_size;
    1239           0 :         ins_size /= csum_size;
    1240           0 :         total_bytes += ins_size * fs_info->sectorsize;
    1241             : 
    1242           0 :         btrfs_mark_buffer_dirty(path->nodes[0]);
    1243           0 :         if (total_bytes < sums->len) {
    1244           0 :                 btrfs_release_path(path);
    1245           0 :                 cond_resched();
    1246           0 :                 goto again;
    1247             :         }
    1248           0 : out:
    1249           0 :         btrfs_free_path(path);
    1250           0 :         return ret;
    1251             : }
    1252             : 
    1253           0 : void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
    1254             :                                      const struct btrfs_path *path,
    1255             :                                      struct btrfs_file_extent_item *fi,
    1256             :                                      struct extent_map *em)
    1257             : {
    1258           0 :         struct btrfs_fs_info *fs_info = inode->root->fs_info;
    1259           0 :         struct btrfs_root *root = inode->root;
    1260           0 :         struct extent_buffer *leaf = path->nodes[0];
    1261           0 :         const int slot = path->slots[0];
    1262           0 :         struct btrfs_key key;
    1263           0 :         u64 extent_start, extent_end;
    1264           0 :         u64 bytenr;
    1265           0 :         u8 type = btrfs_file_extent_type(leaf, fi);
    1266           0 :         int compress_type = btrfs_file_extent_compression(leaf, fi);
    1267             : 
    1268           0 :         btrfs_item_key_to_cpu(leaf, &key, slot);
    1269           0 :         extent_start = key.offset;
    1270           0 :         extent_end = btrfs_file_extent_end(path);
    1271           0 :         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
    1272           0 :         em->generation = btrfs_file_extent_generation(leaf, fi);
    1273           0 :         if (type == BTRFS_FILE_EXTENT_REG ||
    1274             :             type == BTRFS_FILE_EXTENT_PREALLOC) {
    1275           0 :                 em->start = extent_start;
    1276           0 :                 em->len = extent_end - extent_start;
    1277           0 :                 em->orig_start = extent_start -
    1278             :                         btrfs_file_extent_offset(leaf, fi);
    1279           0 :                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
    1280           0 :                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
    1281           0 :                 if (bytenr == 0) {
    1282           0 :                         em->block_start = EXTENT_MAP_HOLE;
    1283           0 :                         return;
    1284             :                 }
    1285           0 :                 if (compress_type != BTRFS_COMPRESS_NONE) {
    1286           0 :                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
    1287           0 :                         em->compress_type = compress_type;
    1288           0 :                         em->block_start = bytenr;
    1289           0 :                         em->block_len = em->orig_block_len;
    1290             :                 } else {
    1291           0 :                         bytenr += btrfs_file_extent_offset(leaf, fi);
    1292           0 :                         em->block_start = bytenr;
    1293           0 :                         em->block_len = em->len;
    1294           0 :                         if (type == BTRFS_FILE_EXTENT_PREALLOC)
    1295           0 :                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
    1296             :                 }
    1297           0 :         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
    1298           0 :                 em->block_start = EXTENT_MAP_INLINE;
    1299           0 :                 em->start = extent_start;
    1300           0 :                 em->len = extent_end - extent_start;
    1301             :                 /*
    1302             :                  * Initialize orig_start and block_len with the same values
    1303             :                  * as in inode.c:btrfs_get_extent().
    1304             :                  */
    1305           0 :                 em->orig_start = EXTENT_MAP_HOLE;
    1306           0 :                 em->block_len = (u64)-1;
    1307           0 :                 em->compress_type = compress_type;
    1308           0 :                 if (compress_type != BTRFS_COMPRESS_NONE)
    1309           0 :                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
    1310             :         } else {
    1311           0 :                 btrfs_err(fs_info,
    1312             :                           "unknown file extent item type %d, inode %llu, offset %llu, "
    1313             :                           "root %llu", type, btrfs_ino(inode), extent_start,
    1314             :                           root->root_key.objectid);
    1315             :         }
    1316             : }
    1317             : 
    1318             : /*
    1319             :  * Returns the end offset (non inclusive) of the file extent item the given path
    1320             :  * points to. If it points to an inline extent, the returned offset is rounded
    1321             :  * up to the sector size.
    1322             :  */
    1323           0 : u64 btrfs_file_extent_end(const struct btrfs_path *path)
    1324             : {
    1325           0 :         const struct extent_buffer *leaf = path->nodes[0];
    1326           0 :         const int slot = path->slots[0];
    1327           0 :         struct btrfs_file_extent_item *fi;
    1328           0 :         struct btrfs_key key;
    1329           0 :         u64 end;
    1330             : 
    1331           0 :         btrfs_item_key_to_cpu(leaf, &key, slot);
    1332           0 :         ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
    1333           0 :         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
    1334             : 
    1335           0 :         if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
    1336           0 :                 end = btrfs_file_extent_ram_bytes(leaf, fi);
    1337           0 :                 end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
    1338             :         } else {
    1339           0 :                 end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
    1340             :         }
    1341             : 
    1342           0 :         return end;
    1343             : }

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