[PATCH 2/3] Btrfs: do not merge rbios if their fail stripe index are not identical

[Liu Bo <bo.li.liu@oracle.com>]

Since fail stripe index in rbio would be used to decide which
algorithm reconstruction would be run, we cannot merge rbios if
their's fail striped index are different, otherwise, one of the two
reconstructions would fail.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/raid56.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index c4188fb..8d09535 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -601,6 +601,15 @@ static int rbio_can_merge(struct btrfs_raid_bio *last,
 	if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
 		return 0;
 
+	if (last->operation == BTRFS_RBIO_READ_REBUILD) {
+		int fa = (last->faila < last->failb) ? last->faila : last->failb;
+		int fb = (last->faila < last->failb) ? last->failb : last->faila;
+		int cur_fa = (cur->faila < cur->failb) ? cur->faila : cur->failb;
+		int cur_fb = (cur->faila < cur->failb) ? cur->failb : cur->faila;
+
+		if (fa != cur_fa || fb != cur_fb)
+			return 0;
+	}
 	return 1;
 }
 
-- 
2.9.4