ext4: fix retry handling in ext4_ext_truncate()

We tested for ENOMEM instead of -ENOMEM.   Oops.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a618738..72ba470 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4412,7 +4412,7 @@
 retry:
 	err = ext4_es_remove_extent(inode, last_block,
 				    EXT_MAX_BLOCKS - last_block);
-	if (err == ENOMEM) {
+	if (err == -ENOMEM) {
 		cond_resched();
 		congestion_wait(BLK_RW_ASYNC, HZ/50);
 		goto retry;