4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Junjie Mao <junjie.mao@enight.me>

commit 14155cafeadda946376260e2ad5d39a0528a332f upstream.

Fixes: 4246a0b63bd8 ("block: add a bi_error field to struct bio")
Signed-off-by: Junjie Mao <junjie.mao@enight.me>
Acked-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/btrfs/compression.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -698,7 +698,7 @@ int btrfs_submit_compressed_read(struct
 
 			ret = btrfs_map_bio(root, comp_bio, mirror_num, 0);
 			if (ret) {
-				bio->bi_error = ret;
+				comp_bio->bi_error = ret;
 				bio_endio(comp_bio);
 			}
 
@@ -728,7 +728,7 @@ int btrfs_submit_compressed_read(struct
 
 	ret = btrfs_map_bio(root, comp_bio, mirror_num, 0);
 	if (ret) {
-		bio->bi_error = ret;
+		comp_bio->bi_error = ret;
 		bio_endio(comp_bio);
 	}