ext4: fix oops in ext4_quota_off()

commit 0b26859027ce0005ef89520af20351360e51ad76 upstream.

If quota is not enabled when ext4_quota_off() is called, we must not
dereference quota file inode since it is NULL.  Check properly for
this.

This fixes a bug in commit 21f976975cbe (ext4: remove unnecessary
[cm]time update of quota file), which was merged for 2.6.39-rc3.

Reported-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e28c0f2..e6ea384 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4635,6 +4635,9 @@ static int ext4_quota_off(struct super_block *sb, int type)
        if (test_opt(sb, DELALLOC))
                sync_filesystem(sb);
 
+       if (!inode)
+               goto out;
+
        /* Update modification times of quota files when userspace can
         * start looking at them */
        handle = ext4_journal_start(inode, 1);