Btrfs: Wait for async bio submissions to make some progress at queue time

Before, the btrfs bdi congestion function was used to test for too many
async bios.  This keeps that check to throttle pdflush, but also
adds a check while queuing bios.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index e904a69347a4..2562a273ae18 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -73,4 +73,5 @@ int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
                         int rw, struct bio *bio, int mirror_num,
                         extent_submit_bio_hook_t *submit_bio_hook);
 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone);
+unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info);
 #endif