btrfs: hold a ref on the root in create_reloc_inode

We're creating a reloc inode in the data reloc tree, we need to hold a
ref on the root while we're doing that.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 976917ca412a9570e925a4c7c7df2f0b415dfaaf..a257147db7a9978addf3d84c40a648814df5566a 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4351,10 +4351,14 @@ struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
        root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
        if (IS_ERR(root))
                return ERR_CAST(root);
+       if (!btrfs_grab_fs_root(root))
+               return ERR_PTR(-ENOENT);
 
        trans = btrfs_start_transaction(root, 6);
-       if (IS_ERR(trans))
+       if (IS_ERR(trans)) {
+               btrfs_put_fs_root(root);
                return ERR_CAST(trans);
+       }
 
        err = btrfs_find_free_objectid(root, &objectid);
        if (err)
@@ -4372,6 +4376,7 @@ struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
 
        err = btrfs_orphan_add(trans, BTRFS_I(inode));
 out:
+       btrfs_put_fs_root(root);
        btrfs_end_transaction(trans);
        btrfs_btree_balance_dirty(fs_info);
        if (err) {