Btrfs: release space on error in page_mkwrite

If updating the inode gave us an ENOSPC we were just returning in page_mkwrite,
which is a problem since we make our reservation right before trying to update
the inode, so fix the out label so that we actually free our reservation.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs/btrfs/inode.c

@@ -6488,8 +6488,8 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	if (!ret)
 		return VM_FAULT_LOCKED;
 	unlock_page(page);
-	btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
 out:
+	btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
 	return ret;
 }