From 695aa786e686f7ae61a7ff2d2a98b98b83680707 Mon Sep 17 00:00:00 2001 From: Deepanshu Kartikey Date: Sun, 21 Jun 2026 04:42:23 +0530 Subject: ocfs2: use inode_lock_nested() for orphan dir locking PREEMPT_RT's rtmutex PI chain walker warns about a lock dependency cycle when inode_lock(orphan_dir_inode) is called while holding inode_lock(file_inode): ocfs2_file_write_iter() inode_lock(file_inode) [class 0] ocfs2_dio_end_io_write() ocfs2_del_inode_from_orphan() inode_lock(orphan_dir_inode) [class 0] <- warning! However this is a false positive. write_iter() is never called on a directory, and orphan_dir is always a directory, so these two locks can never actually conflict in practice. Fix by using inode_lock_nested(orphan_dir_inode, I_MUTEX_NONDIR2) in all three places where orphan_dir_inode is locked in namei.c, placing it in a separate lock class so the rtmutex PI chain walker understands these locks have distinct roles and does not warn about their ordering. Link: https://lore.kernel.org/20260620231223.46588-1-kartikey406@gmail.com Signed-off-by: Deepanshu Kartikey Suggested-by: Matthew Wilcox Reported-by: syzbot+ce129763ce7d7e914739@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ce129763ce7d7e914739 Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Signed-off-by: Andrew Morton --- fs/ocfs2/namei.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/ocfs2') diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c index 1277666c77cd..4cfd7b3d3e1a 100644 --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -2126,7 +2126,7 @@ static int ocfs2_lookup_lock_orphan_dir(struct ocfs2_super *osb, return ret; } - inode_lock(orphan_dir_inode); + inode_lock_nested(orphan_dir_inode, I_MUTEX_NONDIR2); ret = ocfs2_inode_lock(orphan_dir_inode, &orphan_dir_bh, 1); if (ret < 0) { @@ -2725,7 +2725,7 @@ int ocfs2_del_inode_from_orphan(struct ocfs2_super *osb, goto bail; } - inode_lock(orphan_dir_inode); + inode_lock_nested(orphan_dir_inode, I_MUTEX_NONDIR2); status = ocfs2_inode_lock(orphan_dir_inode, &orphan_dir_bh, 1); if (status < 0) { inode_unlock(orphan_dir_inode); @@ -2838,7 +2838,7 @@ int ocfs2_mv_orphaned_inode_to_new(struct inode *dir, goto leave; } - inode_lock(orphan_dir_inode); + inode_lock_nested(orphan_dir_inode, I_MUTEX_NONDIR2); status = ocfs2_inode_lock(orphan_dir_inode, &orphan_dir_bh, 1); if (status < 0) { -- cgit v1.2.3