ext4: Fix ext4_ext_journal_restart() to reflect errors up to the caller

Fix ext4_ext_journal_restart() so it returns any errors reported by 
ext4_journal_extend() and ext4_journal_restart().

Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 3e966da..17ea8bb 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -92,17 +92,16 @@
 	ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
 }
 
-static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
+static int ext4_ext_journal_restart(handle_t *handle, int needed)
 {
 	int err;
 
 	if (handle->h_buffer_credits > needed)
-		return handle;
-	if (!ext4_journal_extend(handle, needed))
-		return handle;
-	err = ext4_journal_restart(handle, needed);
-
-	return handle;
+		return 0;
+	err = ext4_journal_extend(handle, needed);
+	if (err)
+		return err;
+	return ext4_journal_restart(handle, needed);
 }
 
 /*
@@ -1888,11 +1887,9 @@
 		credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
 #endif
 
-		handle = ext4_ext_journal_restart(handle, credits);
-		if (IS_ERR(handle)) {
-			err = PTR_ERR(handle);
+		err = ext4_ext_journal_restart(handle, credits);
+		if (err)
 			goto out;
-		}
 
 		err = ext4_ext_get_access(handle, inode, path + depth);
 		if (err)