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([2405:201:682f:383f:6622:5068:7fd9:7931]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-37d4f2d2919sm2982012a91.9.2026.06.20.16.12.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 20 Jun 2026 16:12:30 -0700 (PDT) From: Deepanshu Kartikey To: mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org, willy@infradead.org Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Deepanshu Kartikey , syzbot+ce129763ce7d7e914739@syzkaller.appspotmail.com Subject: [PATCH v2] ocfs2: use inode_lock_nested() for orphan dir locking Date: Sun, 21 Jun 2026 04:42:23 +0530 Message-ID: <20260620231223.46588-1-kartikey406@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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. Suggested-by: Matthew Wilcox Reported-by: syzbot+ce129763ce7d7e914739@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ce129763ce7d7e914739 Signed-off-by: Deepanshu Kartikey --- Changes in v2: - Replaced inode_lock() with inode_lock_nested(orphan_dir_inode, I_MUTEX_NONDIR2) in all three call sites in namei.c - Dropped incorrect v1 changes to aops.c and namei.c that restructured lock ordering, as the deadlock was a false positive - Approach suggested by Matthew Wilcox --- fs/ocfs2/namei.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) 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) { -- 2.43.0