From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.17-rc1 commit 1c320d8e92925bb7615f83a7b6e3f402a5c2ca63 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ICN2MB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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> Signed-off-by: Baokun Li <libaokun1@huawei.com> --- fs/ext4/mballoc.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index f516c7da7ea8..1075a658c6c5 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -844,30 +844,30 @@ 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]); + } } /* -- 2.39.2