ext4: fix wrong gfp type under transaction

This fixes the allocations with GFP_KERNEL while under a transaction problems
in ext4.  This patch is the same as its ext3 counterpart, just switches these
to GFP_NOFS.

Signed-off-by: Josef Bacik <jbacik@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/extents.c

@@ -1977,7 +1977,7 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
 	 * We start scanning from right side, freeing all the blocks
 	 * after i_size and walking into the tree depth-wise.
 	 */
-	path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
+	path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
 	if (path == NULL) {
 		ext4_journal_stop(handle);
 		return -ENOMEM;