[RFC 8/8] btrfs: use __GFP_NOFAIL in alloc_btrfs_bio

2015-08-05 Thread mhocko
From: Michal Hocko mho...@suse.com

alloc_btrfs_bio is relying on GFP_NOFS to allocate a bio but since mm:
page_alloc: do not lock up GFP_NOFS allocations upon OOM this is
allowed to fail which can lead to
[   37.928625] kernel BUG at fs/btrfs/extent_io.c:4045

This is clearly undesirable and the nofail behavior should be explicit
if the allocation failure cannot be tolerated.

Signed-off-by: Michal Hocko mho...@suse.com
---
 fs/btrfs/volumes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 53af23f2c087..57a99d19533d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4914,7 +4914,7 @@ static struct btrfs_bio *alloc_btrfs_bio(int 
total_stripes, int real_stripes)
 * and the stripes
 */
sizeof(u64) * (total_stripes),
-   GFP_NOFS);
+   GFP_NOFS|__GFP_NOFAIL);
if (!bbio)
return NULL;
 
-- 
2.5.0

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Re: [RFC 8/8] btrfs: use __GFP_NOFAIL in alloc_btrfs_bio

2015-08-05 Thread David Sterba
On Wed, Aug 05, 2015 at 11:51:24AM +0200, mho...@kernel.org wrote:
 From: Michal Hocko mho...@suse.com
 
 alloc_btrfs_bio is relying on GFP_NOFS to allocate a bio but since mm:
 page_alloc: do not lock up GFP_NOFS allocations upon OOM this is
 allowed to fail which can lead to
 [   37.928625] kernel BUG at fs/btrfs/extent_io.c:4045
 
 This is clearly undesirable and the nofail behavior should be explicit
 if the allocation failure cannot be tolerated.
 
 Signed-off-by: Michal Hocko mho...@suse.com

Reviewed-by: David Sterba dste...@suse.com
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