fs: Assign bdi in super_block

We do this automatically in get_sb_bdev() from the set_bdev_super()
callback. Filesystems that have their own private backing_dev_info
must assign that in ->fill_super().

Note that ->s_bdi assignment is required for proper writeback!

Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 15831d5..8b81927 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1600,6 +1600,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
        sb->s_blocksize = 4096;
        sb->s_blocksize_bits = blksize_bits(4096);
+       sb->s_bdi = &fs_info->bdi;
 
        /*
         * we set the i_size on the btree inode to the max possible int.

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 4567db6..e5dbecd 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -894,6 +894,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
        if (err)
                goto err_put_conn;
 
+       sb->s_bdi = &fc->bdi;
+
        /* Handle umasking inside the fuse code */
        if (sb->s_flags & MS_POSIXACL)
                fc->dont_mask = 1;

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 867f705..de93569 100644 (file)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1918,6 +1918,8 @@ static inline void nfs_initialise_sb(struct super_block *sb)
        if (server->flags & NFS_MOUNT_NOAC)
                sb->s_flags |= MS_SYNCHRONOUS;
 
+       sb->s_bdi = &server->backing_dev_info;
+
        nfs_super_set_maxbytes(sb, server->maxfilesize);
 }
 

diff --git a/fs/super.c b/fs/super.c
index 9cda337..b03fea8 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -707,6 +707,12 @@ static int set_bdev_super(struct super_block *s, void *data)
 {
        s->s_bdev = data;
        s->s_dev = s->s_bdev->bd_dev;
+
+       /*
+        * We set the bdi here to the queue backing, file systems can
+        * overwrite this in ->fill_super()
+        */
+       s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
        return 0;
 }
 

diff --git a/fs/sync.c b/fs/sync.c
index 1923409..c08467a 100644 (file)
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -27,6 +27,13 @@
  */
 static int __sync_filesystem(struct super_block *sb, int wait)
 {
+       /*
+        * This should be safe, as we require bdi backing to actually
+        * write out data in the first place
+        */
+       if (!sb->s_bdi)
+               return 0;
+
        /* Avoid doing twice syncing and cache pruning for quota sync */
        if (!wait) {
                writeout_quota_sb(sb, -1);
@@ -101,7 +108,7 @@ restart:
                spin_unlock(&sb_lock);
 
                down_read(&sb->s_umount);
-               if (!(sb->s_flags & MS_RDONLY) && sb->s_root)
+               if (!(sb->s_flags & MS_RDONLY) && sb->s_root && sb->s_bdi)
                        __sync_filesystem(sb, wait);
                up_read(&sb->s_umount);
 

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 51763aa..c4af069 100644 (file)
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1980,6 +1980,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
        if (err)
                goto out_bdi;
 
+       sb->s_bdi = &c->bdi;
        sb->s_fs_info = c;
        sb->s_magic = UBIFS_SUPER_MAGIC;
        sb->s_blocksize = UBIFS_BLOCK_SIZE;

diff --git a/include/linux/fs.h b/include/linux/fs.h
index db29588..90162fb 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1342,6 +1342,7 @@ struct super_block {
        int                     s_nr_dentry_unused;     /* # of dentry on lru */
 
        struct block_device     *s_bdev;
+       struct backing_dev_info *s_bdi;
        struct mtd_info         *s_mtd;
        struct list_head        s_instances;
        struct quota_info       s_dquot;        /* Diskquota specific options */