[PATCH 3.12 109/118] Btrfs: fix hole check in log_one_extent

Greg Kroah-Hartman
2013-12-18T21:19:29Z

From: Josef Bacik <jbacik@fusionio.com>

commit ed9e8af88e2551aaa6bf51d8063a2493e2d71597 upstream.

I added an assert to make sure we were looking up aligned offsets for csums and
I tripped it when running xfstests. This is because log_one_extent was checking
if block_start == 0 for a hole instead of EXTENT_MAP_HOLE. This worked out fine
in practice it seems, but it adds a lot of extra work that is uneeded. With
this fix I'm no longer tripping my assert. Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/tree-log.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3375,7 +3375,7 @@ static int log_one_extent(struct btrfs_t
btrfs_set_token_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG,
&token);
- if (em->block_start == 0)
+ if (em->block_start == EXTENT_MAP_HOLE)
skip_csum = true;
}