+ } else if (src_rsv == &root->fs_info->delalloc_block_rsv) {
+ spin_lock(&BTRFS_I(inode)->lock);
+ if (BTRFS_I(inode)->delalloc_meta_reserved) {
+ BTRFS_I(inode)->delalloc_meta_reserved = 0;
+ spin_unlock(&BTRFS_I(inode)->lock);
+ release = true;
+ goto migrate;
+ }
+ spin_unlock(&BTRFS_I(inode)->lock);
+
+ /* Ok we didn't have space pre-reserved. This shouldn't happen
+ * too often but it can happen if we do delalloc to an existing
+ * inode which gets dirtied because of the time update, and then
+ * isn't touched again until after the transaction commits and
+ * then we try to write out the data. First try to be nice and
+ * reserve something strictly for us. If not be a pain and try
+ * to steal from the delalloc block rsv.
+ */
+ ret = btrfs_block_rsv_add_noflush(root, dst_rsv, num_bytes);
+ if (!ret)
+ goto out;
+
+ ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes);
+ if (!ret)
+ goto out;
+
+ /*
+ * Ok this is a problem, let's just steal from the global rsv
+ * since this really shouldn't happen that often.
+ */
+ WARN_ON(1);
+ ret = btrfs_block_rsv_migrate(&root->fs_info->global_block_rsv,
+ dst_rsv, num_bytes);
+ goto out;