ext4: Add missing unlock to an error path in ext4_quota_write()

From: Jan Kara <jack@suse.cz>

Add missing unlock of i_mutex in the error path of ext4_quota_write().

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

---
 fs/ext4/super.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

Index: linux-2.6.26-rc6/fs/ext4/super.c
===================================================================
--- linux-2.6.26-rc6.orig/fs/ext4/super.c	2008-06-26 15:45:54.000000000 -0700
+++ linux-2.6.26-rc6/fs/ext4/super.c	2008-06-26 15:46:32.000000000 -0700
@@ -3390,8 +3390,10 @@ static ssize_t ext4_quota_write(struct s
 		blk++;
 	}
 out:
-	if (len == towrite)
+	if (len == towrite) {
+		mutex_unlock(&inode->i_mutex);
 		return err;
+	}
 	if (inode->i_size < off+len-towrite) {
 		i_size_write(inode, off+len-towrite);
 		EXT4_I(inode)->i_disksize = inode->i_size;