From e398da0b9131583e0f52bca733eaefc3b3aeae95 Mon Sep 17 00:00:00 2001 From: Daeho Jeong Date: Wed, 9 Sep 2026 12:06:36 -0700 Subject: [PATCH] f2fs: fix livelock in syncing dirty inodes During checkpoint, f2fs_sync_dirty_inodes() and f2fs_sync_inode_meta() iterate over dirty inodes in their respective lists. If igrab() fails on an inode (e.g. because it is in the freeing state), the loop continues without moving the current inode to the tail of the list. As a result, subsequent iterations pick the same inode repeatedly, preventing other ready dirty inodes in the list from making forward progress and leading to a livelock. Fix this by moving the current inode to the tail of the list (list_move_tail(&fi->{dirty_list,gdirty_list}, head)) before attempting igrab() in both f2fs_sync_dirty_inodes() and f2fs_sync_inode_meta(). Additionally, if igrab() fails, yield the CPU with cond_resched() to allow the evicting thread to finish eviction. Remove the redundant f2fs_submit_merged_write() call, since .writepages already submits cached bios via f2fs_submit_merged_write_cond(). v2: - Also apply list_move_tail() to f2fs_sync_dirty_inodes(). - Remove redundant f2fs_submit_merged_write() calls from both functions, keeping only cond_resched(). - Update commit title and description. Signed-off-by: Daeho Jeong Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/checkpoint.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index 712c4508f38c..dffd63eedea8 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -1402,6 +1402,7 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi, enum inode_type type, return 0; } fi = list_first_entry(head, struct f2fs_inode_info, dirty_list); + list_move_tail(&fi->dirty_list, head); inode = igrab(&fi->vfs_inode); spin_unlock(&sbi->inode_lock[type]); if (inode) { @@ -1424,11 +1425,6 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi, enum inode_type type, else ino = cur_ino; } else { - /* - * We should submit bio, since it exists several - * writebacking dentry pages in the freeing inode. - */ - f2fs_submit_merged_write(sbi, DATA); cond_resched(); } goto retry; @@ -1452,6 +1448,7 @@ static int f2fs_sync_inode_meta(struct f2fs_sb_info *sbi) } fi = list_first_entry(head, struct f2fs_inode_info, gdirty_list); + list_move_tail(&fi->gdirty_list, head); inode = igrab(&fi->vfs_inode); spin_unlock(&sbi->inode_lock[DIRTY_META]); if (inode) { @@ -1461,6 +1458,8 @@ static int f2fs_sync_inode_meta(struct f2fs_sb_info *sbi) if (is_inode_flag_set(inode, FI_DIRTY_INODE)) f2fs_update_inode_page(inode); iput(inode); + } else { + cond_resched(); } } return 0;