fs: remove default_backing_dev_info

Now that default_backing_dev_info is not used for writeback purposes we can
git rid of it easily:

 - instead of using it's name for tracing unregistered bdi we just use
   "unknown"
 - btrfs and ceph can just assign the default read ahead window themselves
   like several other filesystems already do.
 - we can assign noop_backing_dev_info as the default one in alloc_super.
   All filesystems already either assigned their own or
   noop_backing_dev_info.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig
2015-01-14 10:42:41 +01:00
committed by Jens Axboe
parent c4db59d31e
commit df0ce26cb4
6 changed files with 6 additions and 22 deletions

View File

@@ -185,8 +185,8 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
}
init_waitqueue_head(&s->s_writers.wait);
init_waitqueue_head(&s->s_writers.wait_unfrozen);
s->s_bdi = &noop_backing_dev_info;
s->s_flags = flags;
s->s_bdi = &default_backing_dev_info;
INIT_HLIST_NODE(&s->s_instances);
INIT_HLIST_BL_HEAD(&s->s_anon);
INIT_LIST_HEAD(&s->s_inodes);
@@ -863,10 +863,7 @@ EXPORT_SYMBOL(free_anon_bdev);
int set_anon_super(struct super_block *s, void *data)
{
int error = get_anon_bdev(&s->s_dev);
if (!error)
s->s_bdi = &noop_backing_dev_info;
return error;
return get_anon_bdev(&s->s_dev);
}
EXPORT_SYMBOL(set_anon_super);
@@ -1111,7 +1108,6 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
sb = root->d_sb;
BUG_ON(!sb);
WARN_ON(!sb->s_bdi);
WARN_ON(sb->s_bdi == &default_backing_dev_info);
sb->s_flags |= MS_BORN;
error = security_sb_kern_mount(sb, flags, secdata);