[PATCH 26/60] btrfs: set NO_MP for request queues behind BTRFS

[Ming Lei <tom.leiming@gmail.com>]

There are lots of direct access to .bi_vcnt & .bi_io_vec
of bio, and it isn't ready to support multipage bvecs
for BTRFS, so set NO_MP for these request queues.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 fs/btrfs/volumes.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 71a60cc01451..2e7237a3b84d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1011,6 +1011,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 		if (blk_queue_discard(q))
 			device->can_discard = 1;
 
+		/* BTRFS isn't ready to support multipage bvecs */
+		set_bit(QUEUE_FLAG_NO_MP, &q->queue_flags);
+
 		device->bdev = bdev;
 		device->in_fs_metadata = 0;
 		device->mode = flags;
-- 
2.7.4