LCOV - code coverage report
Current view: top level - fs/ext4 - resize.c (source / functions) Hit Total Coverage
Test: fstests of 6.5.0-rc3-acha @ Mon Jul 31 20:08:06 PDT 2023 Lines: 0 1186 0.0 %
Date: 2023-07-31 20:08:07 Functions: 0 32 0.0 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  *  linux/fs/ext4/resize.c
       4             :  *
       5             :  * Support for resizing an ext4 filesystem while it is mounted.
       6             :  *
       7             :  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
       8             :  *
       9             :  * This could probably be made into a module, because it is not often in use.
      10             :  */
      11             : 
      12             : 
      13             : #define EXT4FS_DEBUG
      14             : 
      15             : #include <linux/errno.h>
      16             : #include <linux/slab.h>
      17             : #include <linux/jiffies.h>
      18             : 
      19             : #include "ext4_jbd2.h"
      20             : 
      21             : struct ext4_rcu_ptr {
      22             :         struct rcu_head rcu;
      23             :         void *ptr;
      24             : };
      25             : 
      26           0 : static void ext4_rcu_ptr_callback(struct rcu_head *head)
      27             : {
      28           0 :         struct ext4_rcu_ptr *ptr;
      29             : 
      30           0 :         ptr = container_of(head, struct ext4_rcu_ptr, rcu);
      31           0 :         kvfree(ptr->ptr);
      32           0 :         kfree(ptr);
      33           0 : }
      34             : 
      35           0 : void ext4_kvfree_array_rcu(void *to_free)
      36             : {
      37           0 :         struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
      38             : 
      39           0 :         if (ptr) {
      40           0 :                 ptr->ptr = to_free;
      41           0 :                 call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
      42           0 :                 return;
      43             :         }
      44           0 :         synchronize_rcu();
      45           0 :         kvfree(to_free);
      46             : }
      47             : 
      48           0 : int ext4_resize_begin(struct super_block *sb)
      49             : {
      50           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
      51           0 :         int ret = 0;
      52             : 
      53           0 :         if (!capable(CAP_SYS_RESOURCE))
      54             :                 return -EPERM;
      55             : 
      56             :         /*
      57             :          * If the reserved GDT blocks is non-zero, the resize_inode feature
      58             :          * should always be set.
      59             :          */
      60           0 :         if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
      61             :             !ext4_has_feature_resize_inode(sb)) {
      62           0 :                 ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
      63           0 :                 return -EFSCORRUPTED;
      64             :         }
      65             : 
      66             :         /*
      67             :          * If we are not using the primary superblock/GDT copy don't resize,
      68             :          * because the user tools have no way of handling this.  Probably a
      69             :          * bad time to do it anyways.
      70             :          */
      71           0 :         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
      72           0 :             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
      73           0 :                 ext4_warning(sb, "won't resize using backup superblock at %llu",
      74             :                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
      75           0 :                 return -EPERM;
      76             :         }
      77             : 
      78             :         /*
      79             :          * We are not allowed to do online-resizing on a filesystem mounted
      80             :          * with error, because it can destroy the filesystem easily.
      81             :          */
      82           0 :         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
      83           0 :                 ext4_warning(sb, "There are errors in the filesystem, "
      84             :                              "so online resizing is not allowed");
      85           0 :                 return -EPERM;
      86             :         }
      87             : 
      88           0 :         if (ext4_has_feature_sparse_super2(sb)) {
      89           0 :                 ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
      90           0 :                 return -EOPNOTSUPP;
      91             :         }
      92             : 
      93           0 :         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
      94           0 :                                   &EXT4_SB(sb)->s_ext4_flags))
      95           0 :                 ret = -EBUSY;
      96             : 
      97             :         return ret;
      98             : }
      99             : 
     100           0 : int ext4_resize_end(struct super_block *sb, bool update_backups)
     101             : {
     102           0 :         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
     103           0 :         smp_mb__after_atomic();
     104           0 :         if (update_backups)
     105           0 :                 return ext4_update_overhead(sb, true);
     106             :         return 0;
     107             : }
     108             : 
     109             : static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
     110             :                                              ext4_group_t group) {
     111           0 :         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
     112             :                EXT4_DESC_PER_BLOCK_BITS(sb);
     113             : }
     114             : 
     115             : static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
     116             :                                              ext4_group_t group) {
     117           0 :         group = ext4_meta_bg_first_group(sb, group);
     118           0 :         return ext4_group_first_block_no(sb, group);
     119             : }
     120             : 
     121           0 : static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
     122             :                                                 ext4_group_t group) {
     123           0 :         ext4_grpblk_t overhead;
     124           0 :         overhead = ext4_bg_num_gdb(sb, group);
     125           0 :         if (ext4_bg_has_super(sb, group))
     126           0 :                 overhead += 1 +
     127           0 :                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
     128           0 :         return overhead;
     129             : }
     130             : 
     131             : #define outside(b, first, last) ((b) < (first) || (b) >= (last))
     132             : #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
     133             : 
     134           0 : static int verify_group_input(struct super_block *sb,
     135             :                               struct ext4_new_group_data *input)
     136             : {
     137           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
     138           0 :         struct ext4_super_block *es = sbi->s_es;
     139           0 :         ext4_fsblk_t start = ext4_blocks_count(es);
     140           0 :         ext4_fsblk_t end = start + input->blocks_count;
     141           0 :         ext4_group_t group = input->group;
     142           0 :         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
     143           0 :         unsigned overhead;
     144           0 :         ext4_fsblk_t metaend;
     145           0 :         struct buffer_head *bh = NULL;
     146           0 :         ext4_grpblk_t free_blocks_count, offset;
     147           0 :         int err = -EINVAL;
     148             : 
     149           0 :         if (group != sbi->s_groups_count) {
     150           0 :                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
     151             :                              input->group, sbi->s_groups_count);
     152           0 :                 return -EINVAL;
     153             :         }
     154             : 
     155           0 :         overhead = ext4_group_overhead_blocks(sb, group);
     156           0 :         metaend = start + overhead;
     157           0 :         input->free_clusters_count = free_blocks_count =
     158           0 :                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
     159             : 
     160           0 :         if (test_opt(sb, DEBUG))
     161           0 :                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
     162             :                        "(%d free, %u reserved)\n",
     163             :                        ext4_bg_has_super(sb, input->group) ? "normal" :
     164             :                        "no-super", input->group, input->blocks_count,
     165             :                        free_blocks_count, input->reserved_blocks);
     166             : 
     167           0 :         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
     168           0 :         if (offset != 0)
     169           0 :                         ext4_warning(sb, "Last group not full");
     170           0 :         else if (input->reserved_blocks > input->blocks_count / 5)
     171           0 :                 ext4_warning(sb, "Reserved blocks too high (%u)",
     172             :                              input->reserved_blocks);
     173           0 :         else if (free_blocks_count < 0)
     174           0 :                 ext4_warning(sb, "Bad blocks count %u",
     175             :                              input->blocks_count);
     176           0 :         else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
     177           0 :                 err = PTR_ERR(bh);
     178           0 :                 bh = NULL;
     179           0 :                 ext4_warning(sb, "Cannot read last block (%llu)",
     180             :                              end - 1);
     181           0 :         } else if (outside(input->block_bitmap, start, end))
     182           0 :                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
     183             :                              (unsigned long long)input->block_bitmap);
     184           0 :         else if (outside(input->inode_bitmap, start, end))
     185           0 :                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
     186             :                              (unsigned long long)input->inode_bitmap);
     187           0 :         else if (outside(input->inode_table, start, end) ||
     188           0 :                  outside(itend - 1, start, end))
     189           0 :                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
     190             :                              (unsigned long long)input->inode_table, itend - 1);
     191           0 :         else if (input->inode_bitmap == input->block_bitmap)
     192           0 :                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
     193             :                              (unsigned long long)input->block_bitmap);
     194           0 :         else if (inside(input->block_bitmap, input->inode_table, itend))
     195           0 :                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
     196             :                              "(%llu-%llu)",
     197             :                              (unsigned long long)input->block_bitmap,
     198             :                              (unsigned long long)input->inode_table, itend - 1);
     199           0 :         else if (inside(input->inode_bitmap, input->inode_table, itend))
     200           0 :                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
     201             :                              "(%llu-%llu)",
     202             :                              (unsigned long long)input->inode_bitmap,
     203             :                              (unsigned long long)input->inode_table, itend - 1);
     204           0 :         else if (inside(input->block_bitmap, start, metaend))
     205           0 :                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
     206             :                              (unsigned long long)input->block_bitmap,
     207             :                              start, metaend - 1);
     208           0 :         else if (inside(input->inode_bitmap, start, metaend))
     209           0 :                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
     210             :                              (unsigned long long)input->inode_bitmap,
     211             :                              start, metaend - 1);
     212           0 :         else if (inside(input->inode_table, start, metaend) ||
     213           0 :                  inside(itend - 1, start, metaend))
     214           0 :                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
     215             :                              "(%llu-%llu)",
     216             :                              (unsigned long long)input->inode_table,
     217             :                              itend - 1, start, metaend - 1);
     218             :         else
     219             :                 err = 0;
     220           0 :         brelse(bh);
     221             : 
     222             :         return err;
     223             : }
     224             : 
     225             : /*
     226             :  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
     227             :  * group each time.
     228             :  */
     229             : struct ext4_new_flex_group_data {
     230             :         struct ext4_new_group_data *groups;     /* new_group_data for groups
     231             :                                                    in the flex group */
     232             :         __u16 *bg_flags;                        /* block group flags of groups
     233             :                                                    in @groups */
     234             :         ext4_group_t count;                     /* number of groups in @groups
     235             :                                                  */
     236             : };
     237             : 
     238             : /*
     239             :  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
     240             :  * @flexbg_size.
     241             :  *
     242             :  * Returns NULL on failure otherwise address of the allocated structure.
     243             :  */
     244           0 : static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
     245             : {
     246           0 :         struct ext4_new_flex_group_data *flex_gd;
     247             : 
     248           0 :         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
     249           0 :         if (flex_gd == NULL)
     250           0 :                 goto out3;
     251             : 
     252           0 :         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
     253           0 :                 goto out2;
     254           0 :         flex_gd->count = flexbg_size;
     255             : 
     256           0 :         flex_gd->groups = kmalloc_array(flexbg_size,
     257             :                                         sizeof(struct ext4_new_group_data),
     258             :                                         GFP_NOFS);
     259           0 :         if (flex_gd->groups == NULL)
     260           0 :                 goto out2;
     261             : 
     262           0 :         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
     263             :                                           GFP_NOFS);
     264           0 :         if (flex_gd->bg_flags == NULL)
     265           0 :                 goto out1;
     266             : 
     267             :         return flex_gd;
     268             : 
     269             : out1:
     270           0 :         kfree(flex_gd->groups);
     271           0 : out2:
     272           0 :         kfree(flex_gd);
     273             : out3:
     274             :         return NULL;
     275             : }
     276             : 
     277           0 : static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
     278             : {
     279           0 :         kfree(flex_gd->bg_flags);
     280           0 :         kfree(flex_gd->groups);
     281           0 :         kfree(flex_gd);
     282           0 : }
     283             : 
     284             : /*
     285             :  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
     286             :  * and inode tables for a flex group.
     287             :  *
     288             :  * This function is used by 64bit-resize.  Note that this function allocates
     289             :  * group tables from the 1st group of groups contained by @flexgd, which may
     290             :  * be a partial of a flex group.
     291             :  *
     292             :  * @sb: super block of fs to which the groups belongs
     293             :  *
     294             :  * Returns 0 on a successful allocation of the metadata blocks in the
     295             :  * block group.
     296             :  */
     297           0 : static int ext4_alloc_group_tables(struct super_block *sb,
     298             :                                 struct ext4_new_flex_group_data *flex_gd,
     299             :                                 int flexbg_size)
     300             : {
     301           0 :         struct ext4_new_group_data *group_data = flex_gd->groups;
     302           0 :         ext4_fsblk_t start_blk;
     303           0 :         ext4_fsblk_t last_blk;
     304           0 :         ext4_group_t src_group;
     305           0 :         ext4_group_t bb_index = 0;
     306           0 :         ext4_group_t ib_index = 0;
     307           0 :         ext4_group_t it_index = 0;
     308           0 :         ext4_group_t group;
     309           0 :         ext4_group_t last_group;
     310           0 :         unsigned overhead;
     311           0 :         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
     312           0 :         int i;
     313             : 
     314           0 :         BUG_ON(flex_gd->count == 0 || group_data == NULL);
     315             : 
     316           0 :         src_group = group_data[0].group;
     317           0 :         last_group  = src_group + flex_gd->count - 1;
     318             : 
     319           0 :         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
     320             :                (last_group & ~(flexbg_size - 1))));
     321           0 : next_group:
     322           0 :         group = group_data[0].group;
     323           0 :         if (src_group >= group_data[0].group + flex_gd->count)
     324             :                 return -ENOSPC;
     325           0 :         start_blk = ext4_group_first_block_no(sb, src_group);
     326           0 :         last_blk = start_blk + group_data[src_group - group].blocks_count;
     327             : 
     328           0 :         overhead = ext4_group_overhead_blocks(sb, src_group);
     329             : 
     330           0 :         start_blk += overhead;
     331             : 
     332             :         /* We collect contiguous blocks as much as possible. */
     333           0 :         src_group++;
     334           0 :         for (; src_group <= last_group; src_group++) {
     335           0 :                 overhead = ext4_group_overhead_blocks(sb, src_group);
     336           0 :                 if (overhead == 0)
     337           0 :                         last_blk += group_data[src_group - group].blocks_count;
     338             :                 else
     339             :                         break;
     340             :         }
     341             : 
     342             :         /* Allocate block bitmaps */
     343           0 :         for (; bb_index < flex_gd->count; bb_index++) {
     344           0 :                 if (start_blk >= last_blk)
     345           0 :                         goto next_group;
     346           0 :                 group_data[bb_index].block_bitmap = start_blk++;
     347           0 :                 group = ext4_get_group_number(sb, start_blk - 1);
     348           0 :                 group -= group_data[0].group;
     349           0 :                 group_data[group].mdata_blocks++;
     350           0 :                 flex_gd->bg_flags[group] &= uninit_mask;
     351             :         }
     352             : 
     353             :         /* Allocate inode bitmaps */
     354           0 :         for (; ib_index < flex_gd->count; ib_index++) {
     355           0 :                 if (start_blk >= last_blk)
     356           0 :                         goto next_group;
     357           0 :                 group_data[ib_index].inode_bitmap = start_blk++;
     358           0 :                 group = ext4_get_group_number(sb, start_blk - 1);
     359           0 :                 group -= group_data[0].group;
     360           0 :                 group_data[group].mdata_blocks++;
     361           0 :                 flex_gd->bg_flags[group] &= uninit_mask;
     362             :         }
     363             : 
     364             :         /* Allocate inode tables */
     365           0 :         for (; it_index < flex_gd->count; it_index++) {
     366           0 :                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
     367           0 :                 ext4_fsblk_t next_group_start;
     368             : 
     369           0 :                 if (start_blk + itb > last_blk)
     370           0 :                         goto next_group;
     371           0 :                 group_data[it_index].inode_table = start_blk;
     372           0 :                 group = ext4_get_group_number(sb, start_blk);
     373           0 :                 next_group_start = ext4_group_first_block_no(sb, group + 1);
     374           0 :                 group -= group_data[0].group;
     375             : 
     376           0 :                 if (start_blk + itb > next_group_start) {
     377           0 :                         flex_gd->bg_flags[group + 1] &= uninit_mask;
     378           0 :                         overhead = start_blk + itb - next_group_start;
     379           0 :                         group_data[group + 1].mdata_blocks += overhead;
     380           0 :                         itb -= overhead;
     381             :                 }
     382             : 
     383           0 :                 group_data[group].mdata_blocks += itb;
     384           0 :                 flex_gd->bg_flags[group] &= uninit_mask;
     385           0 :                 start_blk += EXT4_SB(sb)->s_itb_per_group;
     386             :         }
     387             : 
     388             :         /* Update free clusters count to exclude metadata blocks */
     389           0 :         for (i = 0; i < flex_gd->count; i++) {
     390           0 :                 group_data[i].free_clusters_count -=
     391           0 :                                 EXT4_NUM_B2C(EXT4_SB(sb),
     392             :                                              group_data[i].mdata_blocks);
     393             :         }
     394             : 
     395           0 :         if (test_opt(sb, DEBUG)) {
     396           0 :                 int i;
     397           0 :                 group = group_data[0].group;
     398             : 
     399           0 :                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
     400             :                        "%d groups, flexbg size is %d:\n", flex_gd->count,
     401             :                        flexbg_size);
     402             : 
     403           0 :                 for (i = 0; i < flex_gd->count; i++) {
     404           0 :                         ext4_debug(
     405             :                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
     406             :                                ext4_bg_has_super(sb, group + i) ? "normal" :
     407             :                                "no-super", group + i,
     408             :                                group_data[i].blocks_count,
     409             :                                group_data[i].free_clusters_count,
     410             :                                group_data[i].mdata_blocks);
     411             :                 }
     412             :         }
     413             :         return 0;
     414             : }
     415             : 
     416           0 : static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
     417             :                                   ext4_fsblk_t blk)
     418             : {
     419           0 :         struct buffer_head *bh;
     420           0 :         int err;
     421             : 
     422           0 :         bh = sb_getblk(sb, blk);
     423           0 :         if (unlikely(!bh))
     424             :                 return ERR_PTR(-ENOMEM);
     425           0 :         BUFFER_TRACE(bh, "get_write_access");
     426           0 :         err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
     427           0 :         if (err) {
     428           0 :                 brelse(bh);
     429           0 :                 bh = ERR_PTR(err);
     430             :         } else {
     431           0 :                 memset(bh->b_data, 0, sb->s_blocksize);
     432           0 :                 set_buffer_uptodate(bh);
     433             :         }
     434             : 
     435             :         return bh;
     436             : }
     437             : 
     438           0 : static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
     439             : {
     440           0 :         return ext4_journal_ensure_credits_fn(handle, credits,
     441             :                 EXT4_MAX_TRANS_DATA, 0, 0);
     442             : }
     443             : 
     444             : /*
     445             :  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
     446             :  *
     447             :  * Helper function for ext4_setup_new_group_blocks() which set .
     448             :  *
     449             :  * @sb: super block
     450             :  * @handle: journal handle
     451             :  * @flex_gd: flex group data
     452             :  */
     453           0 : static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
     454             :                         struct ext4_new_flex_group_data *flex_gd,
     455             :                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
     456             : {
     457           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
     458           0 :         ext4_group_t count = last_cluster - first_cluster + 1;
     459           0 :         ext4_group_t count2;
     460             : 
     461           0 :         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
     462             :                    last_cluster);
     463           0 :         for (count2 = count; count > 0;
     464           0 :              count -= count2, first_cluster += count2) {
     465           0 :                 ext4_fsblk_t start;
     466           0 :                 struct buffer_head *bh;
     467           0 :                 ext4_group_t group;
     468           0 :                 int err;
     469             : 
     470           0 :                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
     471           0 :                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
     472           0 :                 group -= flex_gd->groups[0].group;
     473             : 
     474           0 :                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
     475           0 :                 if (count2 > count)
     476             :                         count2 = count;
     477             : 
     478           0 :                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
     479           0 :                         BUG_ON(flex_gd->count > 1);
     480           0 :                         continue;
     481             :                 }
     482             : 
     483           0 :                 err = ext4_resize_ensure_credits_batch(handle, 1);
     484           0 :                 if (err < 0)
     485           0 :                         return err;
     486             : 
     487           0 :                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
     488           0 :                 if (unlikely(!bh))
     489             :                         return -ENOMEM;
     490             : 
     491           0 :                 BUFFER_TRACE(bh, "get_write_access");
     492           0 :                 err = ext4_journal_get_write_access(handle, sb, bh,
     493             :                                                     EXT4_JTR_NONE);
     494           0 :                 if (err) {
     495           0 :                         brelse(bh);
     496           0 :                         return err;
     497             :                 }
     498           0 :                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
     499             :                            first_cluster, first_cluster - start, count2);
     500           0 :                 mb_set_bits(bh->b_data, first_cluster - start, count2);
     501             : 
     502           0 :                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
     503           0 :                 brelse(bh);
     504           0 :                 if (unlikely(err))
     505           0 :                         return err;
     506             :         }
     507             : 
     508             :         return 0;
     509             : }
     510             : 
     511             : /*
     512             :  * Set up the block and inode bitmaps, and the inode table for the new groups.
     513             :  * This doesn't need to be part of the main transaction, since we are only
     514             :  * changing blocks outside the actual filesystem.  We still do journaling to
     515             :  * ensure the recovery is correct in case of a failure just after resize.
     516             :  * If any part of this fails, we simply abort the resize.
     517             :  *
     518             :  * setup_new_flex_group_blocks handles a flex group as follow:
     519             :  *  1. copy super block and GDT, and initialize group tables if necessary.
     520             :  *     In this step, we only set bits in blocks bitmaps for blocks taken by
     521             :  *     super block and GDT.
     522             :  *  2. allocate group tables in block bitmaps, that is, set bits in block
     523             :  *     bitmap for blocks taken by group tables.
     524             :  */
     525           0 : static int setup_new_flex_group_blocks(struct super_block *sb,
     526             :                                 struct ext4_new_flex_group_data *flex_gd)
     527             : {
     528           0 :         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
     529           0 :         ext4_fsblk_t start;
     530           0 :         ext4_fsblk_t block;
     531           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
     532           0 :         struct ext4_super_block *es = sbi->s_es;
     533           0 :         struct ext4_new_group_data *group_data = flex_gd->groups;
     534           0 :         __u16 *bg_flags = flex_gd->bg_flags;
     535           0 :         handle_t *handle;
     536           0 :         ext4_group_t group, count;
     537           0 :         struct buffer_head *bh = NULL;
     538           0 :         int reserved_gdb, i, j, err = 0, err2;
     539           0 :         int meta_bg;
     540             : 
     541           0 :         BUG_ON(!flex_gd->count || !group_data ||
     542             :                group_data[0].group != sbi->s_groups_count);
     543             : 
     544           0 :         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
     545           0 :         meta_bg = ext4_has_feature_meta_bg(sb);
     546             : 
     547             :         /* This transaction may be extended/restarted along the way */
     548           0 :         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
     549           0 :         if (IS_ERR(handle))
     550           0 :                 return PTR_ERR(handle);
     551             : 
     552           0 :         group = group_data[0].group;
     553           0 :         for (i = 0; i < flex_gd->count; i++, group++) {
     554           0 :                 unsigned long gdblocks;
     555           0 :                 ext4_grpblk_t overhead;
     556             : 
     557           0 :                 gdblocks = ext4_bg_num_gdb(sb, group);
     558           0 :                 start = ext4_group_first_block_no(sb, group);
     559             : 
     560           0 :                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
     561           0 :                         goto handle_itb;
     562             : 
     563           0 :                 if (meta_bg == 1) {
     564           0 :                         ext4_group_t first_group;
     565           0 :                         first_group = ext4_meta_bg_first_group(sb, group);
     566           0 :                         if (first_group != group + 1 &&
     567           0 :                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
     568           0 :                                 goto handle_itb;
     569             :                 }
     570             : 
     571           0 :                 block = start + ext4_bg_has_super(sb, group);
     572             :                 /* Copy all of the GDT blocks into the backup in this group */
     573           0 :                 for (j = 0; j < gdblocks; j++, block++) {
     574           0 :                         struct buffer_head *gdb;
     575             : 
     576           0 :                         ext4_debug("update backup group %#04llx\n", block);
     577           0 :                         err = ext4_resize_ensure_credits_batch(handle, 1);
     578           0 :                         if (err < 0)
     579           0 :                                 goto out;
     580             : 
     581           0 :                         gdb = sb_getblk(sb, block);
     582           0 :                         if (unlikely(!gdb)) {
     583           0 :                                 err = -ENOMEM;
     584           0 :                                 goto out;
     585             :                         }
     586             : 
     587           0 :                         BUFFER_TRACE(gdb, "get_write_access");
     588           0 :                         err = ext4_journal_get_write_access(handle, sb, gdb,
     589             :                                                             EXT4_JTR_NONE);
     590           0 :                         if (err) {
     591           0 :                                 brelse(gdb);
     592           0 :                                 goto out;
     593             :                         }
     594           0 :                         memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
     595             :                                 s_group_desc, j)->b_data, gdb->b_size);
     596           0 :                         set_buffer_uptodate(gdb);
     597             : 
     598           0 :                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
     599           0 :                         if (unlikely(err)) {
     600           0 :                                 brelse(gdb);
     601           0 :                                 goto out;
     602             :                         }
     603           0 :                         brelse(gdb);
     604             :                 }
     605             : 
     606             :                 /* Zero out all of the reserved backup group descriptor
     607             :                  * table blocks
     608             :                  */
     609           0 :                 if (ext4_bg_has_super(sb, group)) {
     610           0 :                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
     611             :                                         reserved_gdb, GFP_NOFS);
     612           0 :                         if (err)
     613           0 :                                 goto out;
     614             :                 }
     615             : 
     616           0 : handle_itb:
     617             :                 /* Initialize group tables of the grop @group */
     618           0 :                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
     619           0 :                         goto handle_bb;
     620             : 
     621             :                 /* Zero out all of the inode table blocks */
     622           0 :                 block = group_data[i].inode_table;
     623           0 :                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
     624             :                            block, sbi->s_itb_per_group);
     625           0 :                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
     626             :                                        GFP_NOFS);
     627           0 :                 if (err)
     628           0 :                         goto out;
     629             : 
     630           0 : handle_bb:
     631           0 :                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
     632           0 :                         goto handle_ib;
     633             : 
     634             :                 /* Initialize block bitmap of the @group */
     635           0 :                 block = group_data[i].block_bitmap;
     636           0 :                 err = ext4_resize_ensure_credits_batch(handle, 1);
     637           0 :                 if (err < 0)
     638           0 :                         goto out;
     639             : 
     640           0 :                 bh = bclean(handle, sb, block);
     641           0 :                 if (IS_ERR(bh)) {
     642           0 :                         err = PTR_ERR(bh);
     643           0 :                         goto out;
     644             :                 }
     645           0 :                 overhead = ext4_group_overhead_blocks(sb, group);
     646           0 :                 if (overhead != 0) {
     647           0 :                         ext4_debug("mark backup superblock %#04llx (+0)\n",
     648             :                                    start);
     649           0 :                         mb_set_bits(bh->b_data, 0,
     650           0 :                                       EXT4_NUM_B2C(sbi, overhead));
     651             :                 }
     652           0 :                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
     653           0 :                                      sb->s_blocksize * 8, bh->b_data);
     654           0 :                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
     655           0 :                 brelse(bh);
     656           0 :                 if (err)
     657           0 :                         goto out;
     658             : 
     659           0 : handle_ib:
     660           0 :                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
     661           0 :                         continue;
     662             : 
     663             :                 /* Initialize inode bitmap of the @group */
     664           0 :                 block = group_data[i].inode_bitmap;
     665           0 :                 err = ext4_resize_ensure_credits_batch(handle, 1);
     666           0 :                 if (err < 0)
     667           0 :                         goto out;
     668             :                 /* Mark unused entries in inode bitmap used */
     669           0 :                 bh = bclean(handle, sb, block);
     670           0 :                 if (IS_ERR(bh)) {
     671           0 :                         err = PTR_ERR(bh);
     672           0 :                         goto out;
     673             :                 }
     674             : 
     675           0 :                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
     676           0 :                                      sb->s_blocksize * 8, bh->b_data);
     677           0 :                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
     678           0 :                 brelse(bh);
     679           0 :                 if (err)
     680           0 :                         goto out;
     681             :         }
     682             : 
     683             :         /* Mark group tables in block bitmap */
     684           0 :         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
     685           0 :                 count = group_table_count[j];
     686           0 :                 start = (&group_data[0].block_bitmap)[j];
     687           0 :                 block = start;
     688           0 :                 for (i = 1; i < flex_gd->count; i++) {
     689           0 :                         block += group_table_count[j];
     690           0 :                         if (block == (&group_data[i].block_bitmap)[j]) {
     691           0 :                                 count += group_table_count[j];
     692           0 :                                 continue;
     693             :                         }
     694           0 :                         err = set_flexbg_block_bitmap(sb, handle,
     695             :                                                       flex_gd,
     696           0 :                                                       EXT4_B2C(sbi, start),
     697           0 :                                                       EXT4_B2C(sbi,
     698             :                                                                start + count
     699             :                                                                - 1));
     700           0 :                         if (err)
     701           0 :                                 goto out;
     702           0 :                         count = group_table_count[j];
     703           0 :                         start = (&group_data[i].block_bitmap)[j];
     704           0 :                         block = start;
     705             :                 }
     706             : 
     707           0 :                 if (count) {
     708           0 :                         err = set_flexbg_block_bitmap(sb, handle,
     709             :                                                       flex_gd,
     710           0 :                                                       EXT4_B2C(sbi, start),
     711           0 :                                                       EXT4_B2C(sbi,
     712             :                                                                start + count
     713             :                                                                - 1));
     714           0 :                         if (err)
     715           0 :                                 goto out;
     716             :                 }
     717             :         }
     718             : 
     719           0 : out:
     720           0 :         err2 = ext4_journal_stop(handle);
     721           0 :         if (err2 && !err)
     722           0 :                 err = err2;
     723             : 
     724             :         return err;
     725             : }
     726             : 
     727             : /*
     728             :  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
     729             :  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
     730             :  * calling this for the first time.  In a sparse filesystem it will be the
     731             :  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
     732             :  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
     733             :  */
     734           0 : unsigned int ext4_list_backups(struct super_block *sb, unsigned int *three,
     735             :                                unsigned int *five, unsigned int *seven)
     736             : {
     737           0 :         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
     738           0 :         unsigned int *min = three;
     739           0 :         int mult = 3;
     740           0 :         unsigned int ret;
     741             : 
     742           0 :         if (ext4_has_feature_sparse_super2(sb)) {
     743           0 :                 do {
     744           0 :                         if (*min > 2)
     745             :                                 return UINT_MAX;
     746           0 :                         ret = le32_to_cpu(es->s_backup_bgs[*min - 1]);
     747           0 :                         *min += 1;
     748           0 :                 } while (!ret);
     749           0 :                 return ret;
     750             :         }
     751             : 
     752           0 :         if (!ext4_has_feature_sparse_super(sb)) {
     753           0 :                 ret = *min;
     754           0 :                 *min += 1;
     755           0 :                 return ret;
     756             :         }
     757             : 
     758           0 :         if (*five < *min) {
     759           0 :                 min = five;
     760           0 :                 mult = 5;
     761             :         }
     762           0 :         if (*seven < *min) {
     763           0 :                 min = seven;
     764           0 :                 mult = 7;
     765             :         }
     766             : 
     767           0 :         ret = *min;
     768           0 :         *min *= mult;
     769             : 
     770           0 :         return ret;
     771             : }
     772             : 
     773             : /*
     774             :  * Check that all of the backup GDT blocks are held in the primary GDT block.
     775             :  * It is assumed that they are stored in group order.  Returns the number of
     776             :  * groups in current filesystem that have BACKUPS, or -ve error code.
     777             :  */
     778           0 : static int verify_reserved_gdb(struct super_block *sb,
     779             :                                ext4_group_t end,
     780             :                                struct buffer_head *primary)
     781             : {
     782           0 :         const ext4_fsblk_t blk = primary->b_blocknr;
     783           0 :         unsigned three = 1;
     784           0 :         unsigned five = 5;
     785           0 :         unsigned seven = 7;
     786           0 :         unsigned grp;
     787           0 :         __le32 *p = (__le32 *)primary->b_data;
     788           0 :         int gdbackups = 0;
     789             : 
     790           0 :         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
     791           0 :                 if (le32_to_cpu(*p++) !=
     792           0 :                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
     793           0 :                         ext4_warning(sb, "reserved GDT %llu"
     794             :                                      " missing grp %d (%llu)",
     795             :                                      blk, grp,
     796             :                                      grp *
     797             :                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
     798             :                                      blk);
     799           0 :                         return -EINVAL;
     800             :                 }
     801           0 :                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
     802             :                         return -EFBIG;
     803             :         }
     804             : 
     805             :         return gdbackups;
     806             : }
     807             : 
     808             : /*
     809             :  * Called when we need to bring a reserved group descriptor table block into
     810             :  * use from the resize inode.  The primary copy of the new GDT block currently
     811             :  * is an indirect block (under the double indirect block in the resize inode).
     812             :  * The new backup GDT blocks will be stored as leaf blocks in this indirect
     813             :  * block, in group order.  Even though we know all the block numbers we need,
     814             :  * we check to ensure that the resize inode has actually reserved these blocks.
     815             :  *
     816             :  * Don't need to update the block bitmaps because the blocks are still in use.
     817             :  *
     818             :  * We get all of the error cases out of the way, so that we are sure to not
     819             :  * fail once we start modifying the data on disk, because JBD has no rollback.
     820             :  */
     821           0 : static int add_new_gdb(handle_t *handle, struct inode *inode,
     822             :                        ext4_group_t group)
     823             : {
     824           0 :         struct super_block *sb = inode->i_sb;
     825           0 :         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
     826           0 :         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
     827           0 :         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
     828           0 :         struct buffer_head **o_group_desc, **n_group_desc = NULL;
     829           0 :         struct buffer_head *dind = NULL;
     830           0 :         struct buffer_head *gdb_bh = NULL;
     831           0 :         int gdbackups;
     832           0 :         struct ext4_iloc iloc = { .bh = NULL };
     833           0 :         __le32 *data;
     834           0 :         int err;
     835             : 
     836           0 :         if (test_opt(sb, DEBUG))
     837           0 :                 printk(KERN_DEBUG
     838             :                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
     839             :                        gdb_num);
     840             : 
     841           0 :         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
     842           0 :         if (IS_ERR(gdb_bh))
     843           0 :                 return PTR_ERR(gdb_bh);
     844             : 
     845           0 :         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
     846           0 :         if (gdbackups < 0) {
     847           0 :                 err = gdbackups;
     848           0 :                 goto errout;
     849             :         }
     850             : 
     851           0 :         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
     852           0 :         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
     853           0 :         if (IS_ERR(dind)) {
     854           0 :                 err = PTR_ERR(dind);
     855           0 :                 dind = NULL;
     856           0 :                 goto errout;
     857             :         }
     858             : 
     859           0 :         data = (__le32 *)dind->b_data;
     860           0 :         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
     861           0 :                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
     862             :                              group, gdblock);
     863           0 :                 err = -EINVAL;
     864           0 :                 goto errout;
     865             :         }
     866             : 
     867           0 :         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
     868           0 :         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
     869             :                                             EXT4_JTR_NONE);
     870           0 :         if (unlikely(err))
     871           0 :                 goto errout;
     872             : 
     873           0 :         BUFFER_TRACE(gdb_bh, "get_write_access");
     874           0 :         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
     875           0 :         if (unlikely(err))
     876           0 :                 goto errout;
     877             : 
     878           0 :         BUFFER_TRACE(dind, "get_write_access");
     879           0 :         err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
     880           0 :         if (unlikely(err)) {
     881           0 :                 ext4_std_error(sb, err);
     882           0 :                 goto errout;
     883             :         }
     884             : 
     885             :         /* ext4_reserve_inode_write() gets a reference on the iloc */
     886           0 :         err = ext4_reserve_inode_write(handle, inode, &iloc);
     887           0 :         if (unlikely(err))
     888           0 :                 goto errout;
     889             : 
     890           0 :         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
     891             :                                 GFP_KERNEL);
     892           0 :         if (!n_group_desc) {
     893           0 :                 err = -ENOMEM;
     894           0 :                 ext4_warning(sb, "not enough memory for %lu groups",
     895             :                              gdb_num + 1);
     896           0 :                 goto errout;
     897             :         }
     898             : 
     899             :         /*
     900             :          * Finally, we have all of the possible failures behind us...
     901             :          *
     902             :          * Remove new GDT block from inode double-indirect block and clear out
     903             :          * the new GDT block for use (which also "frees" the backup GDT blocks
     904             :          * from the reserved inode).  We don't need to change the bitmaps for
     905             :          * these blocks, because they are marked as in-use from being in the
     906             :          * reserved inode, and will become GDT blocks (primary and backup).
     907             :          */
     908           0 :         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
     909           0 :         err = ext4_handle_dirty_metadata(handle, NULL, dind);
     910           0 :         if (unlikely(err)) {
     911           0 :                 ext4_std_error(sb, err);
     912           0 :                 goto errout;
     913             :         }
     914           0 :         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
     915           0 :                            (9 - EXT4_SB(sb)->s_cluster_bits);
     916           0 :         ext4_mark_iloc_dirty(handle, inode, &iloc);
     917           0 :         memset(gdb_bh->b_data, 0, sb->s_blocksize);
     918           0 :         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
     919           0 :         if (unlikely(err)) {
     920           0 :                 ext4_std_error(sb, err);
     921           0 :                 iloc.bh = NULL;
     922           0 :                 goto errout;
     923             :         }
     924           0 :         brelse(dind);
     925             : 
     926           0 :         rcu_read_lock();
     927           0 :         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
     928           0 :         memcpy(n_group_desc, o_group_desc,
     929             :                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
     930           0 :         rcu_read_unlock();
     931           0 :         n_group_desc[gdb_num] = gdb_bh;
     932           0 :         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
     933           0 :         EXT4_SB(sb)->s_gdb_count++;
     934           0 :         ext4_kvfree_array_rcu(o_group_desc);
     935             : 
     936           0 :         lock_buffer(EXT4_SB(sb)->s_sbh);
     937           0 :         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
     938           0 :         ext4_superblock_csum_set(sb);
     939           0 :         unlock_buffer(EXT4_SB(sb)->s_sbh);
     940           0 :         err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
     941           0 :         if (err)
     942           0 :                 ext4_std_error(sb, err);
     943             :         return err;
     944           0 : errout:
     945           0 :         kvfree(n_group_desc);
     946           0 :         brelse(iloc.bh);
     947           0 :         brelse(dind);
     948           0 :         brelse(gdb_bh);
     949             : 
     950             :         ext4_debug("leaving with error %d\n", err);
     951             :         return err;
     952             : }
     953             : 
     954             : /*
     955             :  * add_new_gdb_meta_bg is the sister of add_new_gdb.
     956             :  */
     957           0 : static int add_new_gdb_meta_bg(struct super_block *sb,
     958             :                                handle_t *handle, ext4_group_t group) {
     959           0 :         ext4_fsblk_t gdblock;
     960           0 :         struct buffer_head *gdb_bh;
     961           0 :         struct buffer_head **o_group_desc, **n_group_desc;
     962           0 :         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
     963           0 :         int err;
     964             : 
     965           0 :         gdblock = ext4_meta_bg_first_block_no(sb, group) +
     966           0 :                    ext4_bg_has_super(sb, group);
     967           0 :         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
     968           0 :         if (IS_ERR(gdb_bh))
     969           0 :                 return PTR_ERR(gdb_bh);
     970           0 :         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
     971             :                                 GFP_KERNEL);
     972           0 :         if (!n_group_desc) {
     973           0 :                 brelse(gdb_bh);
     974           0 :                 err = -ENOMEM;
     975           0 :                 ext4_warning(sb, "not enough memory for %lu groups",
     976             :                              gdb_num + 1);
     977           0 :                 return err;
     978             :         }
     979             : 
     980           0 :         rcu_read_lock();
     981           0 :         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
     982           0 :         memcpy(n_group_desc, o_group_desc,
     983             :                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
     984           0 :         rcu_read_unlock();
     985           0 :         n_group_desc[gdb_num] = gdb_bh;
     986             : 
     987           0 :         BUFFER_TRACE(gdb_bh, "get_write_access");
     988           0 :         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
     989           0 :         if (err) {
     990           0 :                 kvfree(n_group_desc);
     991           0 :                 brelse(gdb_bh);
     992           0 :                 return err;
     993             :         }
     994             : 
     995           0 :         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
     996           0 :         EXT4_SB(sb)->s_gdb_count++;
     997           0 :         ext4_kvfree_array_rcu(o_group_desc);
     998           0 :         return err;
     999             : }
    1000             : 
    1001             : /*
    1002             :  * Called when we are adding a new group which has a backup copy of each of
    1003             :  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
    1004             :  * We need to add these reserved backup GDT blocks to the resize inode, so
    1005             :  * that they are kept for future resizing and not allocated to files.
    1006             :  *
    1007             :  * Each reserved backup GDT block will go into a different indirect block.
    1008             :  * The indirect blocks are actually the primary reserved GDT blocks,
    1009             :  * so we know in advance what their block numbers are.  We only get the
    1010             :  * double-indirect block to verify it is pointing to the primary reserved
    1011             :  * GDT blocks so we don't overwrite a data block by accident.  The reserved
    1012             :  * backup GDT blocks are stored in their reserved primary GDT block.
    1013             :  */
    1014           0 : static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
    1015             :                               ext4_group_t group)
    1016             : {
    1017           0 :         struct super_block *sb = inode->i_sb;
    1018           0 :         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
    1019           0 :         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
    1020           0 :         struct buffer_head **primary;
    1021           0 :         struct buffer_head *dind;
    1022           0 :         struct ext4_iloc iloc;
    1023           0 :         ext4_fsblk_t blk;
    1024           0 :         __le32 *data, *end;
    1025           0 :         int gdbackups = 0;
    1026           0 :         int res, i;
    1027           0 :         int err;
    1028             : 
    1029           0 :         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
    1030           0 :         if (!primary)
    1031             :                 return -ENOMEM;
    1032             : 
    1033           0 :         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
    1034           0 :         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
    1035           0 :         if (IS_ERR(dind)) {
    1036           0 :                 err = PTR_ERR(dind);
    1037           0 :                 dind = NULL;
    1038           0 :                 goto exit_free;
    1039             :         }
    1040             : 
    1041           0 :         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
    1042           0 :         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
    1043           0 :                                          EXT4_ADDR_PER_BLOCK(sb));
    1044           0 :         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
    1045             : 
    1046             :         /* Get each reserved primary GDT block and verify it holds backups */
    1047           0 :         for (res = 0; res < reserved_gdb; res++, blk++) {
    1048           0 :                 if (le32_to_cpu(*data) != blk) {
    1049           0 :                         ext4_warning(sb, "reserved block %llu"
    1050             :                                      " not at offset %ld",
    1051             :                                      blk,
    1052             :                                      (long)(data - (__le32 *)dind->b_data));
    1053           0 :                         err = -EINVAL;
    1054           0 :                         goto exit_bh;
    1055             :                 }
    1056           0 :                 primary[res] = ext4_sb_bread(sb, blk, 0);
    1057           0 :                 if (IS_ERR(primary[res])) {
    1058           0 :                         err = PTR_ERR(primary[res]);
    1059           0 :                         primary[res] = NULL;
    1060           0 :                         goto exit_bh;
    1061             :                 }
    1062           0 :                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
    1063           0 :                 if (gdbackups < 0) {
    1064           0 :                         brelse(primary[res]);
    1065           0 :                         err = gdbackups;
    1066           0 :                         goto exit_bh;
    1067             :                 }
    1068           0 :                 if (++data >= end)
    1069           0 :                         data = (__le32 *)dind->b_data;
    1070             :         }
    1071             : 
    1072           0 :         for (i = 0; i < reserved_gdb; i++) {
    1073           0 :                 BUFFER_TRACE(primary[i], "get_write_access");
    1074           0 :                 if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
    1075             :                                                          EXT4_JTR_NONE)))
    1076           0 :                         goto exit_bh;
    1077             :         }
    1078             : 
    1079           0 :         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
    1080           0 :                 goto exit_bh;
    1081             : 
    1082             :         /*
    1083             :          * Finally we can add each of the reserved backup GDT blocks from
    1084             :          * the new group to its reserved primary GDT block.
    1085             :          */
    1086           0 :         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
    1087           0 :         for (i = 0; i < reserved_gdb; i++) {
    1088           0 :                 int err2;
    1089           0 :                 data = (__le32 *)primary[i]->b_data;
    1090             :                 /* printk("reserving backup %lu[%u] = %lu\n",
    1091             :                        primary[i]->b_blocknr, gdbackups,
    1092             :                        blk + primary[i]->b_blocknr); */
    1093           0 :                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
    1094           0 :                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
    1095           0 :                 if (!err)
    1096           0 :                         err = err2;
    1097             :         }
    1098             : 
    1099           0 :         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
    1100           0 :         ext4_mark_iloc_dirty(handle, inode, &iloc);
    1101             : 
    1102           0 : exit_bh:
    1103           0 :         while (--res >= 0)
    1104           0 :                 brelse(primary[res]);
    1105           0 :         brelse(dind);
    1106             : 
    1107           0 : exit_free:
    1108           0 :         kfree(primary);
    1109             : 
    1110           0 :         return err;
    1111             : }
    1112             : 
    1113           0 : static inline void ext4_set_block_group_nr(struct super_block *sb, char *data,
    1114             :                                            ext4_group_t group)
    1115             : {
    1116           0 :         struct ext4_super_block *es = (struct ext4_super_block *) data;
    1117             : 
    1118           0 :         es->s_block_group_nr = cpu_to_le16(group);
    1119           0 :         if (ext4_has_metadata_csum(sb))
    1120           0 :                 es->s_checksum = ext4_superblock_csum(sb, es);
    1121           0 : }
    1122             : 
    1123             : /*
    1124             :  * Update the backup copies of the ext4 metadata.  These don't need to be part
    1125             :  * of the main resize transaction, because e2fsck will re-write them if there
    1126             :  * is a problem (basically only OOM will cause a problem).  However, we
    1127             :  * _should_ update the backups if possible, in case the primary gets trashed
    1128             :  * for some reason and we need to run e2fsck from a backup superblock.  The
    1129             :  * important part is that the new block and inode counts are in the backup
    1130             :  * superblocks, and the location of the new group metadata in the GDT backups.
    1131             :  *
    1132             :  * We do not need take the s_resize_lock for this, because these
    1133             :  * blocks are not otherwise touched by the filesystem code when it is
    1134             :  * mounted.  We don't need to worry about last changing from
    1135             :  * sbi->s_groups_count, because the worst that can happen is that we
    1136             :  * do not copy the full number of backups at this time.  The resize
    1137             :  * which changed s_groups_count will backup again.
    1138             :  */
    1139           0 : static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
    1140             :                            int size, int meta_bg)
    1141             : {
    1142           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1143           0 :         ext4_group_t last;
    1144           0 :         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
    1145           0 :         unsigned three = 1;
    1146           0 :         unsigned five = 5;
    1147           0 :         unsigned seven = 7;
    1148           0 :         ext4_group_t group = 0;
    1149           0 :         int rest = sb->s_blocksize - size;
    1150           0 :         handle_t *handle;
    1151           0 :         int err = 0, err2;
    1152             : 
    1153           0 :         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
    1154           0 :         if (IS_ERR(handle)) {
    1155           0 :                 group = 1;
    1156           0 :                 err = PTR_ERR(handle);
    1157           0 :                 goto exit_err;
    1158             :         }
    1159             : 
    1160           0 :         if (meta_bg == 0) {
    1161           0 :                 group = ext4_list_backups(sb, &three, &five, &seven);
    1162           0 :                 last = sbi->s_groups_count;
    1163             :         } else {
    1164           0 :                 group = ext4_get_group_number(sb, blk_off) + 1;
    1165           0 :                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
    1166             :         }
    1167             : 
    1168           0 :         while (group < sbi->s_groups_count) {
    1169           0 :                 struct buffer_head *bh;
    1170           0 :                 ext4_fsblk_t backup_block;
    1171           0 :                 int has_super = ext4_bg_has_super(sb, group);
    1172           0 :                 ext4_fsblk_t first_block = ext4_group_first_block_no(sb, group);
    1173             : 
    1174             :                 /* Out of journal space, and can't get more - abort - so sad */
    1175           0 :                 err = ext4_resize_ensure_credits_batch(handle, 1);
    1176           0 :                 if (err < 0)
    1177             :                         break;
    1178             : 
    1179           0 :                 if (meta_bg == 0)
    1180           0 :                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
    1181             :                 else
    1182           0 :                         backup_block = first_block + has_super;
    1183             : 
    1184           0 :                 bh = sb_getblk(sb, backup_block);
    1185           0 :                 if (unlikely(!bh)) {
    1186             :                         err = -ENOMEM;
    1187             :                         break;
    1188             :                 }
    1189           0 :                 ext4_debug("update metadata backup %llu(+%llu)\n",
    1190             :                            backup_block, backup_block -
    1191             :                            ext4_group_first_block_no(sb, group));
    1192           0 :                 BUFFER_TRACE(bh, "get_write_access");
    1193           0 :                 if ((err = ext4_journal_get_write_access(handle, sb, bh,
    1194             :                                                          EXT4_JTR_NONE)))
    1195             :                         break;
    1196           0 :                 lock_buffer(bh);
    1197           0 :                 memcpy(bh->b_data, data, size);
    1198           0 :                 if (rest)
    1199           0 :                         memset(bh->b_data + size, 0, rest);
    1200           0 :                 if (has_super && (backup_block == first_block))
    1201           0 :                         ext4_set_block_group_nr(sb, bh->b_data, group);
    1202           0 :                 set_buffer_uptodate(bh);
    1203           0 :                 unlock_buffer(bh);
    1204           0 :                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
    1205           0 :                 if (unlikely(err))
    1206           0 :                         ext4_std_error(sb, err);
    1207           0 :                 brelse(bh);
    1208             : 
    1209           0 :                 if (meta_bg == 0)
    1210           0 :                         group = ext4_list_backups(sb, &three, &five, &seven);
    1211           0 :                 else if (group == last)
    1212             :                         break;
    1213             :                 else
    1214             :                         group = last;
    1215             :         }
    1216           0 :         if ((err2 = ext4_journal_stop(handle)) && !err)
    1217           0 :                 err = err2;
    1218             : 
    1219             :         /*
    1220             :          * Ugh! Need to have e2fsck write the backup copies.  It is too
    1221             :          * late to revert the resize, we shouldn't fail just because of
    1222             :          * the backup copies (they are only needed in case of corruption).
    1223             :          *
    1224             :          * However, if we got here we have a journal problem too, so we
    1225             :          * can't really start a transaction to mark the superblock.
    1226             :          * Chicken out and just set the flag on the hope it will be written
    1227             :          * to disk, and if not - we will simply wait until next fsck.
    1228             :          */
    1229           0 : exit_err:
    1230           0 :         if (err) {
    1231           0 :                 ext4_warning(sb, "can't update backup for group %u (err %d), "
    1232             :                              "forcing fsck on next reboot", group, err);
    1233           0 :                 sbi->s_mount_state &= ~EXT4_VALID_FS;
    1234           0 :                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
    1235           0 :                 mark_buffer_dirty(sbi->s_sbh);
    1236             :         }
    1237           0 : }
    1238             : 
    1239             : /*
    1240             :  * ext4_add_new_descs() adds @count group descriptor of groups
    1241             :  * starting at @group
    1242             :  *
    1243             :  * @handle: journal handle
    1244             :  * @sb: super block
    1245             :  * @group: the group no. of the first group desc to be added
    1246             :  * @resize_inode: the resize inode
    1247             :  * @count: number of group descriptors to be added
    1248             :  */
    1249           0 : static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
    1250             :                               ext4_group_t group, struct inode *resize_inode,
    1251             :                               ext4_group_t count)
    1252             : {
    1253           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1254           0 :         struct ext4_super_block *es = sbi->s_es;
    1255           0 :         struct buffer_head *gdb_bh;
    1256           0 :         int i, gdb_off, gdb_num, err = 0;
    1257           0 :         int meta_bg;
    1258             : 
    1259           0 :         meta_bg = ext4_has_feature_meta_bg(sb);
    1260           0 :         for (i = 0; i < count; i++, group++) {
    1261           0 :                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
    1262           0 :                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
    1263             : 
    1264           0 :                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
    1265           0 :                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
    1266             : 
    1267             :                 /*
    1268             :                  * We will only either add reserved group blocks to a backup group
    1269             :                  * or remove reserved blocks for the first group in a new group block.
    1270             :                  * Doing both would be mean more complex code, and sane people don't
    1271             :                  * use non-sparse filesystems anymore.  This is already checked above.
    1272             :                  */
    1273           0 :                 if (gdb_off) {
    1274           0 :                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
    1275             :                                                      gdb_num);
    1276           0 :                         BUFFER_TRACE(gdb_bh, "get_write_access");
    1277           0 :                         err = ext4_journal_get_write_access(handle, sb, gdb_bh,
    1278             :                                                             EXT4_JTR_NONE);
    1279             : 
    1280           0 :                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
    1281           0 :                                 err = reserve_backup_gdb(handle, resize_inode, group);
    1282           0 :                 } else if (meta_bg != 0) {
    1283           0 :                         err = add_new_gdb_meta_bg(sb, handle, group);
    1284             :                 } else {
    1285           0 :                         err = add_new_gdb(handle, resize_inode, group);
    1286             :                 }
    1287           0 :                 if (err)
    1288             :                         break;
    1289             :         }
    1290           0 :         return err;
    1291             : }
    1292             : 
    1293           0 : static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
    1294             : {
    1295           0 :         struct buffer_head *bh = sb_getblk(sb, block);
    1296           0 :         if (unlikely(!bh))
    1297             :                 return NULL;
    1298           0 :         if (!bh_uptodate_or_lock(bh)) {
    1299           0 :                 if (ext4_read_bh(bh, 0, NULL) < 0) {
    1300           0 :                         brelse(bh);
    1301           0 :                         return NULL;
    1302             :                 }
    1303             :         }
    1304             : 
    1305             :         return bh;
    1306             : }
    1307             : 
    1308           0 : static int ext4_set_bitmap_checksums(struct super_block *sb,
    1309             :                                      struct ext4_group_desc *gdp,
    1310             :                                      struct ext4_new_group_data *group_data)
    1311             : {
    1312           0 :         struct buffer_head *bh;
    1313             : 
    1314           0 :         if (!ext4_has_metadata_csum(sb))
    1315             :                 return 0;
    1316             : 
    1317           0 :         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
    1318           0 :         if (!bh)
    1319             :                 return -EIO;
    1320           0 :         ext4_inode_bitmap_csum_set(sb, gdp, bh,
    1321           0 :                                    EXT4_INODES_PER_GROUP(sb) / 8);
    1322           0 :         brelse(bh);
    1323             : 
    1324           0 :         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
    1325           0 :         if (!bh)
    1326             :                 return -EIO;
    1327           0 :         ext4_block_bitmap_csum_set(sb, gdp, bh);
    1328           0 :         brelse(bh);
    1329             : 
    1330           0 :         return 0;
    1331             : }
    1332             : 
    1333             : /*
    1334             :  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
    1335             :  */
    1336           0 : static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
    1337             :                                 struct ext4_new_flex_group_data *flex_gd)
    1338             : {
    1339           0 :         struct ext4_new_group_data      *group_data = flex_gd->groups;
    1340           0 :         struct ext4_group_desc          *gdp;
    1341           0 :         struct ext4_sb_info             *sbi = EXT4_SB(sb);
    1342           0 :         struct buffer_head              *gdb_bh;
    1343           0 :         ext4_group_t                    group;
    1344           0 :         __u16                           *bg_flags = flex_gd->bg_flags;
    1345           0 :         int                             i, gdb_off, gdb_num, err = 0;
    1346             : 
    1347             : 
    1348           0 :         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
    1349           0 :                 group = group_data->group;
    1350             : 
    1351           0 :                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
    1352           0 :                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
    1353             : 
    1354             :                 /*
    1355             :                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
    1356             :                  */
    1357           0 :                 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
    1358             :                 /* Update group descriptor block for new group */
    1359           0 :                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
    1360           0 :                                                  gdb_off * EXT4_DESC_SIZE(sb));
    1361             : 
    1362           0 :                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
    1363           0 :                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
    1364           0 :                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
    1365           0 :                 err = ext4_set_bitmap_checksums(sb, gdp, group_data);
    1366           0 :                 if (err) {
    1367           0 :                         ext4_std_error(sb, err);
    1368             :                         break;
    1369             :                 }
    1370             : 
    1371           0 :                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
    1372           0 :                 ext4_free_group_clusters_set(sb, gdp,
    1373             :                                              group_data->free_clusters_count);
    1374           0 :                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
    1375           0 :                 if (ext4_has_group_desc_csum(sb))
    1376           0 :                         ext4_itable_unused_set(sb, gdp,
    1377           0 :                                                EXT4_INODES_PER_GROUP(sb));
    1378           0 :                 gdp->bg_flags = cpu_to_le16(*bg_flags);
    1379           0 :                 ext4_group_desc_csum_set(sb, group, gdp);
    1380             : 
    1381           0 :                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
    1382           0 :                 if (unlikely(err)) {
    1383           0 :                         ext4_std_error(sb, err);
    1384             :                         break;
    1385             :                 }
    1386             : 
    1387             :                 /*
    1388             :                  * We can allocate memory for mb_alloc based on the new group
    1389             :                  * descriptor
    1390             :                  */
    1391           0 :                 err = ext4_mb_add_groupinfo(sb, group, gdp);
    1392           0 :                 if (err)
    1393             :                         break;
    1394             :         }
    1395           0 :         return err;
    1396             : }
    1397             : 
    1398             : static void ext4_add_overhead(struct super_block *sb,
    1399             :                               const ext4_fsblk_t overhead)
    1400             : {
    1401           0 :        struct ext4_sb_info *sbi = EXT4_SB(sb);
    1402           0 :        struct ext4_super_block *es = sbi->s_es;
    1403             : 
    1404           0 :        sbi->s_overhead += overhead;
    1405           0 :        es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
    1406           0 :        smp_wmb();
    1407           0 : }
    1408             : 
    1409             : /*
    1410             :  * ext4_update_super() updates the super block so that the newly added
    1411             :  * groups can be seen by the filesystem.
    1412             :  *
    1413             :  * @sb: super block
    1414             :  * @flex_gd: new added groups
    1415             :  */
    1416           0 : static void ext4_update_super(struct super_block *sb,
    1417             :                              struct ext4_new_flex_group_data *flex_gd)
    1418             : {
    1419           0 :         ext4_fsblk_t blocks_count = 0;
    1420           0 :         ext4_fsblk_t free_blocks = 0;
    1421           0 :         ext4_fsblk_t reserved_blocks = 0;
    1422           0 :         struct ext4_new_group_data *group_data = flex_gd->groups;
    1423           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1424           0 :         struct ext4_super_block *es = sbi->s_es;
    1425           0 :         int i;
    1426             : 
    1427           0 :         BUG_ON(flex_gd->count == 0 || group_data == NULL);
    1428             :         /*
    1429             :          * Make the new blocks and inodes valid next.  We do this before
    1430             :          * increasing the group count so that once the group is enabled,
    1431             :          * all of its blocks and inodes are already valid.
    1432             :          *
    1433             :          * We always allocate group-by-group, then block-by-block or
    1434             :          * inode-by-inode within a group, so enabling these
    1435             :          * blocks/inodes before the group is live won't actually let us
    1436             :          * allocate the new space yet.
    1437             :          */
    1438           0 :         for (i = 0; i < flex_gd->count; i++) {
    1439           0 :                 blocks_count += group_data[i].blocks_count;
    1440           0 :                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
    1441             :         }
    1442             : 
    1443           0 :         reserved_blocks = ext4_r_blocks_count(es) * 100;
    1444           0 :         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
    1445           0 :         reserved_blocks *= blocks_count;
    1446           0 :         do_div(reserved_blocks, 100);
    1447             : 
    1448           0 :         lock_buffer(sbi->s_sbh);
    1449           0 :         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
    1450           0 :         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
    1451           0 :         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
    1452           0 :                      flex_gd->count);
    1453           0 :         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
    1454           0 :                      flex_gd->count);
    1455             : 
    1456           0 :         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
    1457             :         /*
    1458             :          * We need to protect s_groups_count against other CPUs seeing
    1459             :          * inconsistent state in the superblock.
    1460             :          *
    1461             :          * The precise rules we use are:
    1462             :          *
    1463             :          * * Writers must perform a smp_wmb() after updating all
    1464             :          *   dependent data and before modifying the groups count
    1465             :          *
    1466             :          * * Readers must perform an smp_rmb() after reading the groups
    1467             :          *   count and before reading any dependent data.
    1468             :          *
    1469             :          * NB. These rules can be relaxed when checking the group count
    1470             :          * while freeing data, as we can only allocate from a block
    1471             :          * group after serialising against the group count, and we can
    1472             :          * only then free after serialising in turn against that
    1473             :          * allocation.
    1474             :          */
    1475           0 :         smp_wmb();
    1476             : 
    1477             :         /* Update the global fs size fields */
    1478           0 :         sbi->s_groups_count += flex_gd->count;
    1479           0 :         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
    1480             :                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
    1481             : 
    1482             :         /* Update the reserved block counts only once the new group is
    1483             :          * active. */
    1484           0 :         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
    1485             :                                 reserved_blocks);
    1486             : 
    1487             :         /* Update the free space counts */
    1488           0 :         percpu_counter_add(&sbi->s_freeclusters_counter,
    1489           0 :                            EXT4_NUM_B2C(sbi, free_blocks));
    1490           0 :         percpu_counter_add(&sbi->s_freeinodes_counter,
    1491           0 :                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
    1492             : 
    1493           0 :         ext4_debug("free blocks count %llu",
    1494             :                    percpu_counter_read(&sbi->s_freeclusters_counter));
    1495           0 :         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
    1496           0 :                 ext4_group_t flex_group;
    1497           0 :                 struct flex_groups *fg;
    1498             : 
    1499           0 :                 flex_group = ext4_flex_group(sbi, group_data[0].group);
    1500           0 :                 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
    1501           0 :                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
    1502             :                              &fg->free_clusters);
    1503           0 :                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
    1504             :                            &fg->free_inodes);
    1505             :         }
    1506             : 
    1507             :         /*
    1508             :          * Update the fs overhead information.
    1509             :          *
    1510             :          * For bigalloc, if the superblock already has a properly calculated
    1511             :          * overhead, update it with a value based on numbers already computed
    1512             :          * above for the newly allocated capacity.
    1513             :          */
    1514           0 :         if (ext4_has_feature_bigalloc(sb) && (sbi->s_overhead != 0))
    1515           0 :                 ext4_add_overhead(sb,
    1516           0 :                         EXT4_NUM_B2C(sbi, blocks_count - free_blocks));
    1517             :         else
    1518           0 :                 ext4_calculate_overhead(sb);
    1519           0 :         es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
    1520             : 
    1521           0 :         ext4_superblock_csum_set(sb);
    1522           0 :         unlock_buffer(sbi->s_sbh);
    1523           0 :         if (test_opt(sb, DEBUG))
    1524           0 :                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
    1525             :                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
    1526             :                        blocks_count, free_blocks, reserved_blocks);
    1527           0 : }
    1528             : 
    1529             : /* Add a flex group to an fs. Ensure we handle all possible error conditions
    1530             :  * _before_ we start modifying the filesystem, because we cannot abort the
    1531             :  * transaction and not have it write the data to disk.
    1532             :  */
    1533           0 : static int ext4_flex_group_add(struct super_block *sb,
    1534             :                                struct inode *resize_inode,
    1535             :                                struct ext4_new_flex_group_data *flex_gd)
    1536             : {
    1537           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1538           0 :         struct ext4_super_block *es = sbi->s_es;
    1539           0 :         ext4_fsblk_t o_blocks_count;
    1540           0 :         ext4_grpblk_t last;
    1541           0 :         ext4_group_t group;
    1542           0 :         handle_t *handle;
    1543           0 :         unsigned reserved_gdb;
    1544           0 :         int err = 0, err2 = 0, credit;
    1545             : 
    1546           0 :         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
    1547             : 
    1548           0 :         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
    1549           0 :         o_blocks_count = ext4_blocks_count(es);
    1550           0 :         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
    1551           0 :         BUG_ON(last);
    1552             : 
    1553           0 :         err = setup_new_flex_group_blocks(sb, flex_gd);
    1554           0 :         if (err)
    1555           0 :                 goto exit;
    1556             :         /*
    1557             :          * We will always be modifying at least the superblock and  GDT
    1558             :          * blocks.  If we are adding a group past the last current GDT block,
    1559             :          * we will also modify the inode and the dindirect block.  If we
    1560             :          * are adding a group with superblock/GDT backups  we will also
    1561             :          * modify each of the reserved GDT dindirect blocks.
    1562             :          */
    1563           0 :         credit = 3;     /* sb, resize inode, resize inode dindirect */
    1564             :         /* GDT blocks */
    1565           0 :         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
    1566           0 :         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
    1567           0 :         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
    1568           0 :         if (IS_ERR(handle)) {
    1569           0 :                 err = PTR_ERR(handle);
    1570           0 :                 goto exit;
    1571             :         }
    1572             : 
    1573           0 :         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
    1574           0 :         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
    1575             :                                             EXT4_JTR_NONE);
    1576           0 :         if (err)
    1577           0 :                 goto exit_journal;
    1578             : 
    1579           0 :         group = flex_gd->groups[0].group;
    1580           0 :         BUG_ON(group != sbi->s_groups_count);
    1581           0 :         err = ext4_add_new_descs(handle, sb, group,
    1582             :                                 resize_inode, flex_gd->count);
    1583           0 :         if (err)
    1584           0 :                 goto exit_journal;
    1585             : 
    1586           0 :         err = ext4_setup_new_descs(handle, sb, flex_gd);
    1587           0 :         if (err)
    1588           0 :                 goto exit_journal;
    1589             : 
    1590           0 :         ext4_update_super(sb, flex_gd);
    1591             : 
    1592           0 :         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
    1593             : 
    1594           0 : exit_journal:
    1595           0 :         err2 = ext4_journal_stop(handle);
    1596           0 :         if (!err)
    1597           0 :                 err = err2;
    1598             : 
    1599           0 :         if (!err) {
    1600           0 :                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
    1601           0 :                 int gdb_num_end = ((group + flex_gd->count - 1) /
    1602             :                                    EXT4_DESC_PER_BLOCK(sb));
    1603           0 :                 int meta_bg = ext4_has_feature_meta_bg(sb);
    1604           0 :                 sector_t old_gdb = 0;
    1605             : 
    1606           0 :                 update_backups(sb, ext4_group_first_block_no(sb, 0),
    1607             :                                (char *)es, sizeof(struct ext4_super_block), 0);
    1608           0 :                 for (; gdb_num <= gdb_num_end; gdb_num++) {
    1609           0 :                         struct buffer_head *gdb_bh;
    1610             : 
    1611           0 :                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
    1612             :                                                      gdb_num);
    1613           0 :                         if (old_gdb == gdb_bh->b_blocknr)
    1614           0 :                                 continue;
    1615           0 :                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
    1616           0 :                                        gdb_bh->b_size, meta_bg);
    1617           0 :                         old_gdb = gdb_bh->b_blocknr;
    1618             :                 }
    1619             :         }
    1620           0 : exit:
    1621           0 :         return err;
    1622             : }
    1623             : 
    1624           0 : static int ext4_setup_next_flex_gd(struct super_block *sb,
    1625             :                                     struct ext4_new_flex_group_data *flex_gd,
    1626             :                                     ext4_fsblk_t n_blocks_count,
    1627             :                                     unsigned long flexbg_size)
    1628             : {
    1629           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1630           0 :         struct ext4_super_block *es = sbi->s_es;
    1631           0 :         struct ext4_new_group_data *group_data = flex_gd->groups;
    1632           0 :         ext4_fsblk_t o_blocks_count;
    1633           0 :         ext4_group_t n_group;
    1634           0 :         ext4_group_t group;
    1635           0 :         ext4_group_t last_group;
    1636           0 :         ext4_grpblk_t last;
    1637           0 :         ext4_grpblk_t clusters_per_group;
    1638           0 :         unsigned long i;
    1639             : 
    1640           0 :         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
    1641             : 
    1642           0 :         o_blocks_count = ext4_blocks_count(es);
    1643             : 
    1644           0 :         if (o_blocks_count == n_blocks_count)
    1645             :                 return 0;
    1646             : 
    1647           0 :         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
    1648           0 :         BUG_ON(last);
    1649           0 :         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
    1650             : 
    1651           0 :         last_group = group | (flexbg_size - 1);
    1652           0 :         if (last_group > n_group)
    1653             :                 last_group = n_group;
    1654             : 
    1655           0 :         flex_gd->count = last_group - group + 1;
    1656             : 
    1657           0 :         for (i = 0; i < flex_gd->count; i++) {
    1658           0 :                 int overhead;
    1659             : 
    1660           0 :                 group_data[i].group = group + i;
    1661           0 :                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
    1662           0 :                 overhead = ext4_group_overhead_blocks(sb, group + i);
    1663           0 :                 group_data[i].mdata_blocks = overhead;
    1664           0 :                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
    1665           0 :                 if (ext4_has_group_desc_csum(sb)) {
    1666           0 :                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
    1667             :                                                EXT4_BG_INODE_UNINIT;
    1668           0 :                         if (!test_opt(sb, INIT_INODE_TABLE))
    1669           0 :                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
    1670             :                 } else
    1671           0 :                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
    1672             :         }
    1673             : 
    1674           0 :         if (last_group == n_group && ext4_has_group_desc_csum(sb))
    1675             :                 /* We need to initialize block bitmap of last group. */
    1676           0 :                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
    1677             : 
    1678           0 :         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
    1679           0 :                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
    1680           0 :                 group_data[i - 1].free_clusters_count -= clusters_per_group -
    1681             :                                                        last - 1;
    1682             :         }
    1683             : 
    1684             :         return 1;
    1685             : }
    1686             : 
    1687             : /* Add group descriptor data to an existing or new group descriptor block.
    1688             :  * Ensure we handle all possible error conditions _before_ we start modifying
    1689             :  * the filesystem, because we cannot abort the transaction and not have it
    1690             :  * write the data to disk.
    1691             :  *
    1692             :  * If we are on a GDT block boundary, we need to get the reserved GDT block.
    1693             :  * Otherwise, we may need to add backup GDT blocks for a sparse group.
    1694             :  *
    1695             :  * We only need to hold the superblock lock while we are actually adding
    1696             :  * in the new group's counts to the superblock.  Prior to that we have
    1697             :  * not really "added" the group at all.  We re-check that we are still
    1698             :  * adding in the last group in case things have changed since verifying.
    1699             :  */
    1700           0 : int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
    1701             : {
    1702           0 :         struct ext4_new_flex_group_data flex_gd;
    1703           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1704           0 :         struct ext4_super_block *es = sbi->s_es;
    1705           0 :         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
    1706           0 :                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
    1707           0 :         struct inode *inode = NULL;
    1708           0 :         int gdb_off;
    1709           0 :         int err;
    1710           0 :         __u16 bg_flags = 0;
    1711             : 
    1712           0 :         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
    1713             : 
    1714           0 :         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
    1715           0 :                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
    1716           0 :                 return -EPERM;
    1717             :         }
    1718             : 
    1719           0 :         if (ext4_blocks_count(es) + input->blocks_count <
    1720             :             ext4_blocks_count(es)) {
    1721           0 :                 ext4_warning(sb, "blocks_count overflow");
    1722           0 :                 return -EINVAL;
    1723             :         }
    1724             : 
    1725           0 :         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
    1726             :             le32_to_cpu(es->s_inodes_count)) {
    1727           0 :                 ext4_warning(sb, "inodes_count overflow");
    1728           0 :                 return -EINVAL;
    1729             :         }
    1730             : 
    1731           0 :         if (reserved_gdb || gdb_off == 0) {
    1732           0 :                 if (!ext4_has_feature_resize_inode(sb) ||
    1733           0 :                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
    1734           0 :                         ext4_warning(sb,
    1735             :                                      "No reserved GDT blocks, can't resize");
    1736           0 :                         return -EPERM;
    1737             :                 }
    1738           0 :                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
    1739           0 :                 if (IS_ERR(inode)) {
    1740           0 :                         ext4_warning(sb, "Error opening resize inode");
    1741           0 :                         return PTR_ERR(inode);
    1742             :                 }
    1743             :         }
    1744             : 
    1745             : 
    1746           0 :         err = verify_group_input(sb, input);
    1747           0 :         if (err)
    1748           0 :                 goto out;
    1749             : 
    1750           0 :         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
    1751           0 :         if (err)
    1752           0 :                 goto out;
    1753             : 
    1754           0 :         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
    1755           0 :         if (err)
    1756           0 :                 goto out;
    1757             : 
    1758           0 :         flex_gd.count = 1;
    1759           0 :         flex_gd.groups = input;
    1760           0 :         flex_gd.bg_flags = &bg_flags;
    1761           0 :         err = ext4_flex_group_add(sb, inode, &flex_gd);
    1762           0 : out:
    1763           0 :         iput(inode);
    1764           0 :         return err;
    1765             : } /* ext4_group_add */
    1766             : 
    1767             : /*
    1768             :  * extend a group without checking assuming that checking has been done.
    1769             :  */
    1770           0 : static int ext4_group_extend_no_check(struct super_block *sb,
    1771             :                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
    1772             : {
    1773           0 :         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
    1774           0 :         handle_t *handle;
    1775           0 :         int err = 0, err2;
    1776             : 
    1777             :         /* We will update the superblock, one block bitmap, and
    1778             :          * one group descriptor via ext4_group_add_blocks().
    1779             :          */
    1780           0 :         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
    1781           0 :         if (IS_ERR(handle)) {
    1782           0 :                 err = PTR_ERR(handle);
    1783           0 :                 ext4_warning(sb, "error %d on journal start", err);
    1784           0 :                 return err;
    1785             :         }
    1786             : 
    1787           0 :         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
    1788           0 :         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
    1789             :                                             EXT4_JTR_NONE);
    1790           0 :         if (err) {
    1791           0 :                 ext4_warning(sb, "error %d on journal write access", err);
    1792           0 :                 goto errout;
    1793             :         }
    1794             : 
    1795           0 :         lock_buffer(EXT4_SB(sb)->s_sbh);
    1796           0 :         ext4_blocks_count_set(es, o_blocks_count + add);
    1797           0 :         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
    1798           0 :         ext4_superblock_csum_set(sb);
    1799           0 :         unlock_buffer(EXT4_SB(sb)->s_sbh);
    1800           0 :         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
    1801             :                    o_blocks_count + add);
    1802             :         /* We add the blocks to the bitmap and set the group need init bit */
    1803           0 :         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
    1804           0 :         if (err)
    1805           0 :                 goto errout;
    1806           0 :         ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
    1807           0 :         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
    1808             :                    o_blocks_count + add);
    1809           0 : errout:
    1810           0 :         err2 = ext4_journal_stop(handle);
    1811           0 :         if (err2 && !err)
    1812           0 :                 err = err2;
    1813             : 
    1814           0 :         if (!err) {
    1815           0 :                 if (test_opt(sb, DEBUG))
    1816           0 :                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
    1817             :                                "blocks\n", ext4_blocks_count(es));
    1818           0 :                 update_backups(sb, ext4_group_first_block_no(sb, 0),
    1819             :                                (char *)es, sizeof(struct ext4_super_block), 0);
    1820             :         }
    1821             :         return err;
    1822             : }
    1823             : 
    1824             : /*
    1825             :  * Extend the filesystem to the new number of blocks specified.  This entry
    1826             :  * point is only used to extend the current filesystem to the end of the last
    1827             :  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
    1828             :  * for emergencies (because it has no dependencies on reserved blocks).
    1829             :  *
    1830             :  * If we _really_ wanted, we could use default values to call ext4_group_add()
    1831             :  * allow the "remount" trick to work for arbitrary resizing, assuming enough
    1832             :  * GDT blocks are reserved to grow to the desired size.
    1833             :  */
    1834           0 : int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
    1835             :                       ext4_fsblk_t n_blocks_count)
    1836             : {
    1837           0 :         ext4_fsblk_t o_blocks_count;
    1838           0 :         ext4_grpblk_t last;
    1839           0 :         ext4_grpblk_t add;
    1840           0 :         struct buffer_head *bh;
    1841           0 :         ext4_group_t group;
    1842             : 
    1843           0 :         o_blocks_count = ext4_blocks_count(es);
    1844             : 
    1845           0 :         if (test_opt(sb, DEBUG))
    1846           0 :                 ext4_msg(sb, KERN_DEBUG,
    1847             :                          "extending last group from %llu to %llu blocks",
    1848             :                          o_blocks_count, n_blocks_count);
    1849             : 
    1850           0 :         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
    1851             :                 return 0;
    1852             : 
    1853           0 :         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
    1854           0 :                 ext4_msg(sb, KERN_ERR,
    1855             :                          "filesystem too large to resize to %llu blocks safely",
    1856             :                          n_blocks_count);
    1857           0 :                 return -EINVAL;
    1858             :         }
    1859             : 
    1860           0 :         if (n_blocks_count < o_blocks_count) {
    1861           0 :                 ext4_warning(sb, "can't shrink FS - resize aborted");
    1862           0 :                 return -EINVAL;
    1863             :         }
    1864             : 
    1865             :         /* Handle the remaining blocks in the last group only. */
    1866           0 :         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
    1867             : 
    1868           0 :         if (last == 0) {
    1869           0 :                 ext4_warning(sb, "need to use ext2online to resize further");
    1870           0 :                 return -EPERM;
    1871             :         }
    1872             : 
    1873           0 :         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
    1874             : 
    1875           0 :         if (o_blocks_count + add < o_blocks_count) {
    1876           0 :                 ext4_warning(sb, "blocks_count overflow");
    1877           0 :                 return -EINVAL;
    1878             :         }
    1879             : 
    1880           0 :         if (o_blocks_count + add > n_blocks_count)
    1881           0 :                 add = n_blocks_count - o_blocks_count;
    1882             : 
    1883           0 :         if (o_blocks_count + add < n_blocks_count)
    1884           0 :                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
    1885             :                              o_blocks_count + add, add);
    1886             : 
    1887             :         /* See if the device is actually as big as what was requested */
    1888           0 :         bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
    1889           0 :         if (IS_ERR(bh)) {
    1890           0 :                 ext4_warning(sb, "can't read last block, resize aborted");
    1891           0 :                 return -ENOSPC;
    1892             :         }
    1893           0 :         brelse(bh);
    1894             : 
    1895           0 :         return ext4_group_extend_no_check(sb, o_blocks_count, add);
    1896             : } /* ext4_group_extend */
    1897             : 
    1898             : 
    1899             : static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
    1900             : {
    1901           0 :         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
    1902             : }
    1903             : 
    1904             : /*
    1905             :  * Release the resize inode and drop the resize_inode feature if there
    1906             :  * are no more reserved gdt blocks, and then convert the file system
    1907             :  * to enable meta_bg
    1908             :  */
    1909           0 : static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
    1910             : {
    1911           0 :         handle_t *handle;
    1912           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    1913           0 :         struct ext4_super_block *es = sbi->s_es;
    1914           0 :         struct ext4_inode_info *ei = EXT4_I(inode);
    1915           0 :         ext4_fsblk_t nr;
    1916           0 :         int i, ret, err = 0;
    1917           0 :         int credits = 1;
    1918             : 
    1919           0 :         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
    1920           0 :         if (inode) {
    1921           0 :                 if (es->s_reserved_gdt_blocks) {
    1922           0 :                         ext4_error(sb, "Unexpected non-zero "
    1923             :                                    "s_reserved_gdt_blocks");
    1924           0 :                         return -EPERM;
    1925             :                 }
    1926             : 
    1927             :                 /* Do a quick sanity check of the resize inode */
    1928           0 :                 if (inode->i_blocks != 1 << (inode->i_blkbits -
    1929           0 :                                              (9 - sbi->s_cluster_bits)))
    1930           0 :                         goto invalid_resize_inode;
    1931           0 :                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
    1932           0 :                         if (i == EXT4_DIND_BLOCK) {
    1933           0 :                                 if (ei->i_data[i])
    1934           0 :                                         continue;
    1935             :                                 else
    1936           0 :                                         goto invalid_resize_inode;
    1937             :                         }
    1938           0 :                         if (ei->i_data[i])
    1939           0 :                                 goto invalid_resize_inode;
    1940             :                 }
    1941             :                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
    1942             :         }
    1943             : 
    1944           0 :         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
    1945           0 :         if (IS_ERR(handle))
    1946           0 :                 return PTR_ERR(handle);
    1947             : 
    1948           0 :         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
    1949           0 :         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
    1950             :                                             EXT4_JTR_NONE);
    1951           0 :         if (err)
    1952           0 :                 goto errout;
    1953             : 
    1954           0 :         lock_buffer(sbi->s_sbh);
    1955           0 :         ext4_clear_feature_resize_inode(sb);
    1956           0 :         ext4_set_feature_meta_bg(sb);
    1957           0 :         sbi->s_es->s_first_meta_bg =
    1958           0 :                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
    1959           0 :         ext4_superblock_csum_set(sb);
    1960           0 :         unlock_buffer(sbi->s_sbh);
    1961             : 
    1962           0 :         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
    1963           0 :         if (err) {
    1964           0 :                 ext4_std_error(sb, err);
    1965           0 :                 goto errout;
    1966             :         }
    1967             : 
    1968           0 :         if (inode) {
    1969           0 :                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
    1970           0 :                 ext4_free_blocks(handle, inode, NULL, nr, 1,
    1971             :                                  EXT4_FREE_BLOCKS_METADATA |
    1972             :                                  EXT4_FREE_BLOCKS_FORGET);
    1973           0 :                 ei->i_data[EXT4_DIND_BLOCK] = 0;
    1974           0 :                 inode->i_blocks = 0;
    1975             : 
    1976           0 :                 err = ext4_mark_inode_dirty(handle, inode);
    1977           0 :                 if (err)
    1978           0 :                         ext4_std_error(sb, err);
    1979             :         }
    1980             : 
    1981           0 : errout:
    1982           0 :         ret = ext4_journal_stop(handle);
    1983           0 :         if (!err)
    1984             :                 err = ret;
    1985             :         return ret;
    1986             : 
    1987           0 : invalid_resize_inode:
    1988           0 :         ext4_error(sb, "corrupted/inconsistent resize inode");
    1989           0 :         return -EINVAL;
    1990             : }
    1991             : 
    1992             : /*
    1993             :  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
    1994             :  *
    1995             :  * @sb: super block of the fs to be resized
    1996             :  * @n_blocks_count: the number of blocks resides in the resized fs
    1997             :  */
    1998           0 : int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
    1999             : {
    2000           0 :         struct ext4_new_flex_group_data *flex_gd = NULL;
    2001           0 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
    2002           0 :         struct ext4_super_block *es = sbi->s_es;
    2003           0 :         struct buffer_head *bh;
    2004           0 :         struct inode *resize_inode = NULL;
    2005           0 :         ext4_grpblk_t add, offset;
    2006           0 :         unsigned long n_desc_blocks;
    2007           0 :         unsigned long o_desc_blocks;
    2008           0 :         ext4_group_t o_group;
    2009           0 :         ext4_group_t n_group;
    2010           0 :         ext4_fsblk_t o_blocks_count;
    2011           0 :         ext4_fsblk_t n_blocks_count_retry = 0;
    2012           0 :         unsigned long last_update_time = 0;
    2013           0 :         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
    2014           0 :         int meta_bg;
    2015             : 
    2016             :         /* See if the device is actually as big as what was requested */
    2017           0 :         bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
    2018           0 :         if (IS_ERR(bh)) {
    2019           0 :                 ext4_warning(sb, "can't read last block, resize aborted");
    2020           0 :                 return -ENOSPC;
    2021             :         }
    2022           0 :         brelse(bh);
    2023             : 
    2024             :         /*
    2025             :          * For bigalloc, trim the requested size to the nearest cluster
    2026             :          * boundary to avoid creating an unusable filesystem. We do this
    2027             :          * silently, instead of returning an error, to avoid breaking
    2028             :          * callers that blindly resize the filesystem to the full size of
    2029             :          * the underlying block device.
    2030             :          */
    2031           0 :         if (ext4_has_feature_bigalloc(sb))
    2032           0 :                 n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
    2033             : 
    2034           0 : retry:
    2035           0 :         o_blocks_count = ext4_blocks_count(es);
    2036             : 
    2037           0 :         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
    2038             :                  "to %llu blocks", o_blocks_count, n_blocks_count);
    2039             : 
    2040           0 :         if (n_blocks_count < o_blocks_count) {
    2041             :                 /* On-line shrinking not supported */
    2042           0 :                 ext4_warning(sb, "can't shrink FS - resize aborted");
    2043           0 :                 return -EINVAL;
    2044             :         }
    2045             : 
    2046           0 :         if (n_blocks_count == o_blocks_count)
    2047             :                 /* Nothing need to do */
    2048             :                 return 0;
    2049             : 
    2050           0 :         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
    2051           0 :         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
    2052           0 :                 ext4_warning(sb, "resize would cause inodes_count overflow");
    2053           0 :                 return -EINVAL;
    2054             :         }
    2055           0 :         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
    2056             : 
    2057           0 :         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
    2058           0 :         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
    2059             : 
    2060           0 :         meta_bg = ext4_has_feature_meta_bg(sb);
    2061             : 
    2062           0 :         if (ext4_has_feature_resize_inode(sb)) {
    2063           0 :                 if (meta_bg) {
    2064           0 :                         ext4_error(sb, "resize_inode and meta_bg enabled "
    2065             :                                    "simultaneously");
    2066           0 :                         return -EINVAL;
    2067             :                 }
    2068           0 :                 if (n_desc_blocks > o_desc_blocks +
    2069           0 :                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
    2070           0 :                         n_blocks_count_retry = n_blocks_count;
    2071           0 :                         n_desc_blocks = o_desc_blocks +
    2072             :                                 le16_to_cpu(es->s_reserved_gdt_blocks);
    2073           0 :                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
    2074           0 :                         n_blocks_count = (ext4_fsblk_t)n_group *
    2075           0 :                                 EXT4_BLOCKS_PER_GROUP(sb) +
    2076           0 :                                 le32_to_cpu(es->s_first_data_block);
    2077           0 :                         n_group--; /* set to last group number */
    2078             :                 }
    2079             : 
    2080           0 :                 if (!resize_inode)
    2081           0 :                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
    2082             :                                                  EXT4_IGET_SPECIAL);
    2083           0 :                 if (IS_ERR(resize_inode)) {
    2084           0 :                         ext4_warning(sb, "Error opening resize inode");
    2085           0 :                         return PTR_ERR(resize_inode);
    2086             :                 }
    2087             :         }
    2088             : 
    2089           0 :         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
    2090           0 :                 err = ext4_convert_meta_bg(sb, resize_inode);
    2091           0 :                 if (err)
    2092           0 :                         goto out;
    2093           0 :                 if (resize_inode) {
    2094           0 :                         iput(resize_inode);
    2095           0 :                         resize_inode = NULL;
    2096             :                 }
    2097           0 :                 if (n_blocks_count_retry) {
    2098           0 :                         n_blocks_count = n_blocks_count_retry;
    2099           0 :                         n_blocks_count_retry = 0;
    2100           0 :                         goto retry;
    2101             :                 }
    2102             :         }
    2103             : 
    2104             :         /*
    2105             :          * Make sure the last group has enough space so that it's
    2106             :          * guaranteed to have enough space for all metadata blocks
    2107             :          * that it might need to hold.  (We might not need to store
    2108             :          * the inode table blocks in the last block group, but there
    2109             :          * will be cases where this might be needed.)
    2110             :          */
    2111           0 :         if ((ext4_group_first_block_no(sb, n_group) +
    2112           0 :              ext4_group_overhead_blocks(sb, n_group) + 2 +
    2113           0 :              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
    2114           0 :                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
    2115           0 :                 n_group--;
    2116           0 :                 n_blocks_count_retry = 0;
    2117           0 :                 if (resize_inode) {
    2118           0 :                         iput(resize_inode);
    2119           0 :                         resize_inode = NULL;
    2120             :                 }
    2121           0 :                 goto retry;
    2122             :         }
    2123             : 
    2124             :         /* extend the last group */
    2125           0 :         if (n_group == o_group)
    2126           0 :                 add = n_blocks_count - o_blocks_count;
    2127             :         else
    2128           0 :                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
    2129           0 :         if (add > 0) {
    2130           0 :                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
    2131           0 :                 if (err)
    2132           0 :                         goto out;
    2133             :         }
    2134             : 
    2135           0 :         if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
    2136           0 :                 goto out;
    2137             : 
    2138           0 :         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
    2139           0 :         if (err)
    2140           0 :                 goto out;
    2141             : 
    2142           0 :         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
    2143           0 :         if (err)
    2144           0 :                 goto out;
    2145             : 
    2146           0 :         flex_gd = alloc_flex_gd(flexbg_size);
    2147           0 :         if (flex_gd == NULL) {
    2148           0 :                 err = -ENOMEM;
    2149           0 :                 goto out;
    2150             :         }
    2151             : 
    2152             :         /* Add flex groups. Note that a regular group is a
    2153             :          * flex group with 1 group.
    2154             :          */
    2155           0 :         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
    2156             :                                               flexbg_size)) {
    2157           0 :                 if (time_is_before_jiffies(last_update_time + HZ * 10)) {
    2158           0 :                         if (last_update_time)
    2159           0 :                                 ext4_msg(sb, KERN_INFO,
    2160             :                                          "resized to %llu blocks",
    2161             :                                          ext4_blocks_count(es));
    2162           0 :                         last_update_time = jiffies;
    2163             :                 }
    2164           0 :                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
    2165             :                         break;
    2166           0 :                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
    2167           0 :                 if (unlikely(err))
    2168             :                         break;
    2169             :         }
    2170             : 
    2171           0 :         if (!err && n_blocks_count_retry) {
    2172           0 :                 n_blocks_count = n_blocks_count_retry;
    2173           0 :                 n_blocks_count_retry = 0;
    2174           0 :                 free_flex_gd(flex_gd);
    2175           0 :                 flex_gd = NULL;
    2176           0 :                 if (resize_inode) {
    2177           0 :                         iput(resize_inode);
    2178           0 :                         resize_inode = NULL;
    2179             :                 }
    2180           0 :                 goto retry;
    2181             :         }
    2182             : 
    2183           0 : out:
    2184           0 :         if (flex_gd)
    2185           0 :                 free_flex_gd(flex_gd);
    2186           0 :         if (resize_inode != NULL)
    2187           0 :                 iput(resize_inode);
    2188           0 :         if (err)
    2189           0 :                 ext4_warning(sb, "error (%d) occurred during "
    2190             :                              "file system resize", err);
    2191           0 :         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
    2192             :                  ext4_blocks_count(es));
    2193           0 :         return err;
    2194             : }

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