+ ocfs2-use-inode_lock_nested-for-orphan-dir-locking.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: ocfs2: use inode_lock_nested() for orphan dir locking
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     ocfs2-use-inode_lock_nested-for-orphan-dir-locking.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-use-inode_lock_nested-for-orphan-dir-locking.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Deepanshu Kartikey <kartikey406@gmail.com>
Subject: ocfs2: use inode_lock_nested() for orphan dir locking
Date: Sun, 21 Jun 2026 04:42:23 +0530

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 <kartikey406@gmail.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reported-by: syzbot+ce129763ce7d7e914739@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ce129763ce7d7e914739
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ocfs2/namei.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/ocfs2/namei.c~ocfs2-use-inode_lock_nested-for-orphan-dir-locking
+++ a/fs/ocfs2/namei.c
@@ -2126,7 +2126,7 @@ static int ocfs2_lookup_lock_orphan_dir(
 		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 o
 		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(struc
 		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) {
_

Patches currently in -mm which might be from kartikey406@gmail.com are

ocfs2-use-inode_lock_nested-for-orphan-dir-locking.patch