diff options
| author | Baokun Li <libaokun1@huawei.com> | 2025-07-14 21:03:20 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2025-07-25 09:14:17 -0400 |
| commit | 1c320d8e92925bb7615f83a7b6e3f402a5c2ca63 (patch) | |
| tree | db1d464e5ffafee815bb44213b6b52450211d049 | |
| parent | e7f101a8088770e8f3bb089f13652b9b0fd22b06 (diff) | |
ext4: fix zombie groups in average fragment size lists
Groups with no free blocks shouldn't be in any average fragment size list.
However, when all blocks in a group are allocated(i.e., bb_fragments or
bb_free is 0), we currently skip updating the average fragment size, which
means the group isn't removed from its previous s_mb_avg_fragment_size[old]
list.
This created "zombie" groups that were always skipped during traversal as
they couldn't satisfy any block allocation requests, negatively impacting
traversal efficiency.
Therefore, when a group becomes completely full, bb_avg_fragment_size_order
is now set to -1. If the old order was not -1, a removal operation is
performed; if the new order is not -1, an insertion is performed.
Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@vger.kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-11-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/mballoc.c | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 6d98f2a5afc4..72b20fc52bbf 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -841,30 +841,30 @@ static void mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp) { struct ext4_sb_info *sbi = EXT4_SB(sb); - int new_order; + int new, old; - if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_fragments == 0) + if (!test_opt2(sb, MB_OPTIMIZE_SCAN)) return; - new_order = mb_avg_fragment_size_order(sb, - grp->bb_free / grp->bb_fragments); - if (new_order == grp->bb_avg_fragment_size_order) + old = grp->bb_avg_fragment_size_order; + new = grp->bb_fragments == 0 ? -1 : + mb_avg_fragment_size_order(sb, grp->bb_free / grp->bb_fragments); + if (new == old) return; - if (grp->bb_avg_fragment_size_order != -1) { - write_lock(&sbi->s_mb_avg_fragment_size_locks[ - grp->bb_avg_fragment_size_order]); + if (old >= 0) { + write_lock(&sbi->s_mb_avg_fragment_size_locks[old]); list_del(&grp->bb_avg_fragment_size_node); - write_unlock(&sbi->s_mb_avg_fragment_size_locks[ - grp->bb_avg_fragment_size_order]); - } - grp->bb_avg_fragment_size_order = new_order; - write_lock(&sbi->s_mb_avg_fragment_size_locks[ - grp->bb_avg_fragment_size_order]); - list_add_tail(&grp->bb_avg_fragment_size_node, - &sbi->s_mb_avg_fragment_size[grp->bb_avg_fragment_size_order]); - write_unlock(&sbi->s_mb_avg_fragment_size_locks[ - grp->bb_avg_fragment_size_order]); + write_unlock(&sbi->s_mb_avg_fragment_size_locks[old]); + } + + grp->bb_avg_fragment_size_order = new; + if (new >= 0) { + write_lock(&sbi->s_mb_avg_fragment_size_locks[new]); + list_add_tail(&grp->bb_avg_fragment_size_node, + &sbi->s_mb_avg_fragment_size[new]); + write_unlock(&sbi->s_mb_avg_fragment_size_locks[new]); + } } /* |