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From:   Al Viro <viro@zeniv.linux.org.uk>
To:     linux-arch@vger.kernel.org
Cc:     gus Gusenleitner Klaus <gus@keba.com>,
        Al Viro <viro@ftp.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        lkml <linux-kernel@vger.kernel.org>,
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        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        "dsahern@kernel.org" <dsahern@kernel.org>,
        "kuba@kernel.org" <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Eric Dumazet <edumazet@google.com>
Subject: [PATCH v2 2/9] ocfs2: Avoid touching renamed directory if parent does not change
Date:   Tue,  5 Dec 2023 02:23:55 +0000
Message-Id: <20231205022418.1703007-4-viro@zeniv.linux.org.uk>
In-Reply-To: <20231205022418.1703007-1-viro@zeniv.linux.org.uk>
References: <20231205022100.GB1674809@ZenIV>
 <20231205022418.1703007-1-viro@zeniv.linux.org.uk>
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Sender: Al Viro <viro@ftp.linux.org.uk>
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From: Jan Kara <jack@suse.cz>

The VFS will not be locking moved directory if its parent does not
change. Change ocfs2 rename code to avoid touching renamed directory if
its parent does not change as without locking that can corrupt the
filesystem.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/ocfs2/namei.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 814733ba2f4b..9221a33f917b 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -1336,7 +1336,7 @@ static int ocfs2_rename(struct mnt_idmap *idmap,
 		goto bail;
 	}
 
-	if (S_ISDIR(old_inode->i_mode)) {
+	if (S_ISDIR(old_inode->i_mode) && new_dir != old_dir) {
 		u64 old_inode_parent;
 
 		update_dot_dot = 1;
@@ -1353,8 +1353,7 @@ static int ocfs2_rename(struct mnt_idmap *idmap,
 			goto bail;
 		}
 
-		if (!new_inode && new_dir != old_dir &&
-		    new_dir->i_nlink >= ocfs2_link_max(osb)) {
+		if (!new_inode && new_dir->i_nlink >= ocfs2_link_max(osb)) {
 			status = -EMLINK;
 			goto bail;
 		}
@@ -1601,6 +1600,9 @@ static int ocfs2_rename(struct mnt_idmap *idmap,
 			mlog_errno(status);
 			goto bail;
 		}
+	}
+
+	if (S_ISDIR(old_inode->i_mode)) {
 		drop_nlink(old_dir);
 		if (new_inode) {
 			drop_nlink(new_inode);
-- 
2.39.2