Btrfs: explicitly use global_block_rsv for quota_tree

The quota_tree was set up to use the empty_block_rsv before
which would be problematic when the filesystem is filled up
and ENOSPC happens during internal operations while the quota
tree is updated and COWed (when the btrfs_qgroup_info_item
items) are written. In fact, use_block_rsv() which is used
in btrfs_cow_block() falls back to the global_block_rsv in
this case. But just in order to make it more clear what is
happening, change it to explicitly use the global_block_rsv.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 42f5e6196021d980c93db42fb2d44606b75d83ee..df472ab1b5acca7b411b05bcc414913bcebcc244 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4564,6 +4564,8 @@ static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
        fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
        fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
        fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
+       if (fs_info->quota_root)
+               fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
        fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
 
        update_global_block_rsv(fs_info);