btrfs: Convert to separately allocated bdi

Allocate struct backing_dev_info separately instead of embedding it
inside superblock. This unifies handling of bdi among users.

CC: Chris Mason <clm@fb.com>
CC: Josef Bacik <jbacik@fb.com>
CC: David Sterba <dsterba@suse.com>
CC: linux-btrfs@vger.kernel.org
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index da687dc79cce..e0a7503ab31e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1133,6 +1133,13 @@ static int btrfs_fill_super(struct super_block *sb,
 #endif
         sb->s_flags |= MS_I_VERSION;
         sb->s_iflags |= SB_I_CGROUPWB;
+
+        err = super_setup_bdi(sb);
+        if (err) {
+                btrfs_err(fs_info, "super_setup_bdi failed");
+                return err;
+        }
+
         err = open_ctree(sb, fs_devices, (char *)data);
         if (err) {
                 btrfs_err(fs_info, "open_ctree failed");