Btrfs: create special free space cache inode

In order to save free space cache, we need an inode to hold the data, and we
need a special item to point at the right inode for the right block group.  So
first, create a special item that will point to the right inode, and the number
of extent entries we will have and the number of bitmaps we will have.  We
truncate and pre-allocate space everytime to make sure it's uptodate.

This feature will be turned on as soon as you mount with -o space_cache, however
it is safe to boot into old kernels, they will just generate the cache the old
fashion way.  When you boot back into a newer kernel we will notice that we
modified and not the cache and automatically discard the cache.

Signed-off-by: Josef Bacik <josef@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 64f10082f048..45cf64fc1e3e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1685,7 +1685,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         __setup_root(4096, 4096, 4096, 4096, tree_root,
                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
 
-
         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
         if (!bh)
                 goto fail_iput;
@@ -1993,6 +1992,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         if (!(sb->s_flags & MS_RDONLY)) {
                 down_read(&fs_info->cleanup_work_sem);
                 btrfs_orphan_cleanup(fs_info->fs_root);
+                btrfs_orphan_cleanup(fs_info->tree_root);
                 up_read(&fs_info->cleanup_work_sem);
         }
 
@@ -2421,6 +2421,7 @@ int close_ctree(struct btrfs_root *root)
         fs_info->closing = 1;
         smp_mb();
 
+        btrfs_put_block_group_cache(fs_info);
         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
                 ret =  btrfs_commit_super(root);
                 if (ret)