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ext4: avoid bb_free and bb_fragments inconsistency in mb_free_blocks()
After updating bb_free in mb_free_blocks, it is possible to return without
updating bb_fragments because the block being freed is found to have
already been freed, which leads to inconsistency between bb_free and
bb_fragments.
Since the group may be unlocked in ext4_grp_locked_error(), this can lead
to problems such as dividing by zero when calculating the average fragment
length. Hence move the update of bb_free to after the block double-free
check guarantees that the corresponding statistics are updated only after
the core block bitmap is modified.
Fixes: eabe0444df
("ext4: speed-up releasing blocks on commit")
CC: <stable@vger.kernel.org> # 3.10
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240104142040.2835097-5-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
parent
c9b528c357
commit
2331fd4a49
1 changed files with 21 additions and 18 deletions
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@ -1909,11 +1909,6 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
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mb_check_buddy(e4b);
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mb_check_buddy(e4b);
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mb_free_blocks_double(inode, e4b, first, count);
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mb_free_blocks_double(inode, e4b, first, count);
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this_cpu_inc(discard_pa_seq);
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e4b->bd_info->bb_free += count;
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if (first < e4b->bd_info->bb_first_free)
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e4b->bd_info->bb_first_free = first;
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/* access memory sequentially: check left neighbour,
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/* access memory sequentially: check left neighbour,
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* clear range and then check right neighbour
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* clear range and then check right neighbour
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*/
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*/
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@ -1927,23 +1922,31 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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ext4_fsblk_t blocknr;
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ext4_fsblk_t blocknr;
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/*
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* Fastcommit replay can free already freed blocks which
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* corrupts allocation info. Regenerate it.
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*/
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if (sbi->s_mount_state & EXT4_FC_REPLAY) {
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mb_regenerate_buddy(e4b);
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goto check;
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}
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blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
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blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
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blocknr += EXT4_C2B(sbi, block);
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blocknr += EXT4_C2B(sbi, block);
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if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
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ext4_grp_locked_error(sb, e4b->bd_group,
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ext4_grp_locked_error(sb, e4b->bd_group,
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inode ? inode->i_ino : 0, blocknr,
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inode ? inode->i_ino : 0,
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"freeing already freed block (bit %u); block bitmap corrupt.",
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blocknr,
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block);
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"freeing already freed block (bit %u); block bitmap corrupt.",
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ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
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block);
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ext4_mark_group_bitmap_corrupted(
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sb, e4b->bd_group,
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EXT4_GROUP_INFO_BBITMAP_CORRUPT);
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EXT4_GROUP_INFO_BBITMAP_CORRUPT);
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} else {
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return;
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mb_regenerate_buddy(e4b);
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}
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goto done;
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}
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}
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this_cpu_inc(discard_pa_seq);
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e4b->bd_info->bb_free += count;
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if (first < e4b->bd_info->bb_first_free)
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e4b->bd_info->bb_first_free = first;
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/* let's maintain fragments counter */
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/* let's maintain fragments counter */
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if (left_is_free && right_is_free)
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if (left_is_free && right_is_free)
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e4b->bd_info->bb_fragments--;
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e4b->bd_info->bb_fragments--;
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@ -1968,9 +1971,9 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
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if (first <= last)
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if (first <= last)
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mb_buddy_mark_free(e4b, first >> 1, last >> 1);
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mb_buddy_mark_free(e4b, first >> 1, last >> 1);
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done:
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mb_set_largest_free_order(sb, e4b->bd_info);
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mb_set_largest_free_order(sb, e4b->bd_info);
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mb_update_avg_fragment_size(sb, e4b->bd_info);
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mb_update_avg_fragment_size(sb, e4b->bd_info);
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check:
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mb_check_buddy(e4b);
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mb_check_buddy(e4b);
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}
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}
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