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>

3 files changed, 14 insertions, 30 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 29b7fc28c607..f6019ce20035 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -810,7 +810,6 @@ struct btrfs_fs_info {
         struct btrfs_super_block *super_for_commit;
         struct super_block *sb;
         struct inode *btree_inode;
-        struct backing_dev_info bdi;
         struct mutex tree_log_mutex;
         struct mutex transaction_kthread_mutex;
         struct mutex cleaner_mutex;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 08b74daf35d0..a7d8c342f604 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1808,21 +1808,6 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
         return ret;
 }
 
-static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
-{
-        int err;
-
-        err = bdi_setup_and_register(bdi, "btrfs");
-        if (err)
-                return err;
-
-        bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
-        bdi->congested_fn       = btrfs_congested_fn;
-        bdi->congested_data     = info;
-        bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
-        return 0;
-}
-
 /*
  * called by the kthread helper functions to finally call the bio end_io
  * functions.  This is where read checksum verification actually happens
@@ -2601,16 +2586,10 @@ int open_ctree(struct super_block *sb,
                 goto fail;
         }
 
-        ret = setup_bdi(fs_info, &fs_info->bdi);
-        if (ret) {
-                err = ret;
-                goto fail_srcu;
-        }
-
         ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
         if (ret) {
                 err = ret;
-                goto fail_bdi;
+                goto fail_srcu;
         }
         fs_info->dirty_metadata_batch = PAGE_SIZE *
                                         (1 + ilog2(nr_cpu_ids));
@@ -2718,7 +2697,6 @@ int open_ctree(struct super_block *sb,
 
         sb->s_blocksize = 4096;
         sb->s_blocksize_bits = blksize_bits(4096);
-        sb->s_bdi = &fs_info->bdi;
 
         btrfs_init_btree_inode(fs_info);
 
@@ -2915,9 +2893,12 @@ int open_ctree(struct super_block *sb,
                 goto fail_sb_buffer;
         }
 
-        fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
-        fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
-                                    SZ_4M / PAGE_SIZE);
+        sb->s_bdi->congested_fn = btrfs_congested_fn;
+        sb->s_bdi->congested_data = fs_info;
+        sb->s_bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
+        sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
+        sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
+        sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
 
         sb->s_blocksize = sectorsize;
         sb->s_blocksize_bits = blksize_bits(sectorsize);
@@ -3285,8 +3266,6 @@ fail_delalloc_bytes:
         percpu_counter_destroy(&fs_info->delalloc_bytes);
 fail_dirty_metadata_bytes:
         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
-fail_bdi:
-        bdi_destroy(&fs_info->bdi);
 fail_srcu:
         cleanup_srcu_struct(&fs_info->subvol_srcu);
 fail:
@@ -4007,7 +3986,6 @@ void close_ctree(struct btrfs_fs_info *fs_info)
         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
         percpu_counter_destroy(&fs_info->delalloc_bytes);
         percpu_counter_destroy(&fs_info->bio_counter);
-        bdi_destroy(&fs_info->bdi);
         cleanup_srcu_struct(&fs_info->subvol_srcu);
 
         btrfs_free_stripe_hash_table(fs_info);
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");