From: Josef Bacik <josef@redhat.com>
Date: Tue, 25 Jan 2011 22:11:54 +0000 (+0000)
Subject: Btrfs: handle no memory properly in prepare_pages
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7adf5dfbb3af65a00e20b3ead224c3a1b40e4ec4;p=linux-beck.git

Btrfs: handle no memory properly in prepare_pages

Instead of doing a BUG_ON(1) in prepare_pages if grab_cache_page() fails, just
loop through the pages we've already grabbed and unlock and release them, then
return -ENOMEM like we should.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 65b2424a4116..9e097fbfc78d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -792,8 +792,12 @@ again:
 	for (i = 0; i < num_pages; i++) {
 		pages[i] = grab_cache_page(inode->i_mapping, index + i);
 		if (!pages[i]) {
-			err = -ENOMEM;
-			BUG_ON(1);
+			int c;
+			for (c = i - 1; c >= 0; c--) {
+				unlock_page(pages[c]);
+				page_cache_release(pages[c]);
+			}
+			return -ENOMEM;
 		}
 		wait_on_page_writeback(pages[i]);
 	}