[92/93] ext4: lock i_mutex when truncating orphan inodes

Message ID 1371555821-12820-93-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques June 18, 2013, 11:43 a.m. -stable review patch.  If anyone has any objections, please let me know.


From: Theodore Ts'o <tytso@mit.edu>

commit 721e3eba21e43532e438652dd8f1fcdfce3187e7 upstream.

Commit c278531d39 added a warning when ext4_flush_unwritten_io() is
called without i_mutex being taken.  It had previously not been taken
during orphan cleanup since races weren't possible at that point in
the mount process, but as a result of this c278531d39, we will now see
a kernel WARN_ON in this case.  Take the i_mutex in
ext4_orphan_cleanup() to suppress this warning.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
 fs/ext4/super.c | 2 ++
 1 file changed, 2 insertions(+)


diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index df4b8db..89abdd7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2208,7 +2208,9 @@  static void ext4_orphan_cleanup(struct super_block *sb,
 				__func__, inode->i_ino, inode->i_size);
 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
 				  inode->i_ino, inode->i_size);
+			mutex_lock(&inode->i_mutex);
+			mutex_unlock(&inode->i_mutex);
 		} else {
 			ext4_msg(sb, KERN_DEBUG,