treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks

Don't emit OOM warnings when k.alloc calls fail when
there there is a v.alloc immediately afterwards.

Converted a kmalloc/vmalloc with memset to kzalloc/vzalloc.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index d3f3b43..2e14fd8 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -219,7 +219,7 @@
 	len = PAGE_ALIGN(len);
 
 	if (p->buf == p->inline_buf) {
-		tmp_buf = kmalloc(len, GFP_NOFS);
+		tmp_buf = kmalloc(len, GFP_NOFS | __GFP_NOWARN);
 		if (!tmp_buf) {
 			tmp_buf = vmalloc(len);
 			if (!tmp_buf)