Btrfs: add support for blkio controllers

This attaches accounting information to bios as we submit them so the
new blkio controllers can throttle on btrfs filesystems.

Not much is required, we're just associating bios with blkcgs during clone,
calling wbc_init_bio()/wbc_account_io() during writepages submission,
and attaching the bios to the current context during direct IO.

Finally if we are splitting bios during btrfs_map_bio, this attaches
accounting information to the split.

The end result is able to throttle nicely on single disk filesystems.  A
little more work is required for multi-device filesystems.

Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 79a73645346e..bda3c41dc9d5 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7987,7 +7987,11 @@ static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
                                        u64 first_sector, gfp_t gfp_flags)
 {
         int nr_vecs = bio_get_nr_vecs(bdev);
-        return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
+        struct bio *bio;
+        bio = btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
+        if (bio)
+                bio_associate_current(bio);
+        return bio;
 }
 
 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,