Btrfs: Audit callers and return codes to make sure -ENOSPC gets up the stack

Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/ctree.c

@@ -73,6 +73,7 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
 {
 	struct buffer_head *cow;
 	struct btrfs_node *cow_node;
+	int ret;
 
 	if (btrfs_header_generation(btrfs_buffer_header(buf)) ==
 				    trans->transid) {
@@ -80,6 +81,8 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
 		return 0;
 	}
 	cow = btrfs_alloc_free_block(trans, root, buf->b_blocknr);
+	if (IS_ERR(cow))
+		return PTR_ERR(cow);
 	cow_node = btrfs_buffer_node(cow);
 	if (buf->b_size != root->blocksize || cow->b_size != root->blocksize)
 		WARN_ON(1);
@@ -87,7 +90,9 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
 	btrfs_set_header_blocknr(&cow_node->header, bh_blocknr(cow));
 	btrfs_set_header_generation(&cow_node->header, trans->transid);
 	btrfs_set_header_owner(&cow_node->header, root->root_key.objectid);
-	btrfs_inc_ref(trans, root, buf);
+	ret = btrfs_inc_ref(trans, root, buf);
+	if (ret)
+		return ret;
 	if (buf == root->node) {
 		root->node = cow;
 		get_bh(cow);
@@ -320,6 +325,7 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
 	int wret;
 	int pslot;
 	int orig_slot = path->slots[level];
+	int err_on_enospc = 0;
 	u64 orig_ptr;
 
 	if (level == 0)
@@ -363,29 +369,43 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
 	    BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 		return 0;
 
+	if (btrfs_header_nritems(&mid->header) < 2)
+		err_on_enospc = 1;
+
 	left_buf = read_node_slot(root, parent_buf, pslot - 1);
 	right_buf = read_node_slot(root, parent_buf, pslot + 1);
 
 	/* first, try to make some room in the middle buffer */
 	if (left_buf) {
-		btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
-				&left_buf);
+		wret = btrfs_cow_block(trans, root, left_buf,
+				       parent_buf, pslot - 1, &left_buf);
+		if (wret) {
+			ret = wret;
+			goto enospc;
+		}
 		left = btrfs_buffer_node(left_buf);
 		orig_slot += btrfs_header_nritems(&left->header);
 		wret = push_node_left(trans, root, left_buf, mid_buf);
 		if (wret < 0)
 			ret = wret;
+		if (btrfs_header_nritems(&mid->header) < 2)
+			err_on_enospc = 1;
 	}
 
 	/*
 	 * then try to empty the right most buffer into the middle
 	 */
 	if (right_buf) {
-		btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
-				&right_buf);
+		wret = btrfs_cow_block(trans, root, right_buf,
+				       parent_buf, pslot + 1, &right_buf);
+		if (wret) {
+			ret = wret;
+			goto enospc;
+		}
+
 		right = btrfs_buffer_node(right_buf);
 		wret = push_node_left(trans, root, mid_buf, right_buf);
-		if (wret < 0)
+		if (wret < 0 && wret != -ENOSPC)
 			ret = wret;
 		if (btrfs_header_nritems(&right->header) == 0) {
 			u64 blocknr = bh_blocknr(right_buf);
@@ -421,8 +441,10 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
 		 */
 		BUG_ON(!left_buf);
 		wret = balance_node_right(trans, root, mid_buf, left_buf);
-		if (wret < 0)
+		if (wret < 0) {
 			ret = wret;
+			goto enospc;
+		}
 		BUG_ON(wret == 1);
 	}
 	if (btrfs_header_nritems(&mid->header) == 0) {
@@ -467,7 +489,7 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
 	    btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]),
 				path->slots[level]))
 		BUG();
-
+enospc:
 	if (right_buf)
 		btrfs_block_release(root, right_buf);
 	if (left_buf)
@@ -519,10 +541,15 @@ static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 		if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 			wret = 1;
 		} else {
-			btrfs_cow_block(trans, root, left_buf, parent_buf,
-					pslot - 1, &left_buf);
-			left = btrfs_buffer_node(left_buf);
-			wret = push_node_left(trans, root, left_buf, mid_buf);
+			ret = btrfs_cow_block(trans, root, left_buf, parent_buf,
+					      pslot - 1, &left_buf);
+			if (ret)
+				wret = 1;
+			else {
+				left = btrfs_buffer_node(left_buf);
+				wret = push_node_left(trans, root,
+						      left_buf, mid_buf);
+			}
 		}
 		if (wret < 0)
 			ret = wret;
@@ -561,11 +588,16 @@ static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 		if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 			wret = 1;
 		} else {
-			btrfs_cow_block(trans, root, right_buf,
-					parent_buf, pslot + 1, &right_buf);
-			right = btrfs_buffer_node(right_buf);
-			wret = balance_node_right(trans, root,
-						  right_buf, mid_buf);
+			ret = btrfs_cow_block(trans, root, right_buf,
+					      parent_buf, pslot + 1,
+					      &right_buf);
+			if (ret)
+				wret = 1;
+			else {
+				right = btrfs_buffer_node(right_buf);
+				wret = balance_node_right(trans, root,
+							  right_buf, mid_buf);
+			}
 		}
 		if (wret < 0)
 			ret = wret;
@@ -631,6 +663,10 @@ again:
 					       p->nodes[level + 1],
 					       p->slots[level + 1],
 					       &cow_buf);
+			if (wret) {
+				btrfs_block_release(root, cow_buf);
+				return wret;
+			}
 			b = cow_buf;
 			c = btrfs_buffer_node(b);
 		}
@@ -737,6 +773,7 @@ static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
 	src_nritems = btrfs_header_nritems(&src->header);
 	dst_nritems = btrfs_header_nritems(&dst->header);
 	push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
+
 	if (push_items <= 0) {
 		return 1;
 	}
@@ -827,6 +864,8 @@ static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
 	BUG_ON(path->nodes[level-1] != root->node);
 
 	t = btrfs_alloc_free_block(trans, root, root->node->b_blocknr);
+	if (IS_ERR(t))
+		return PTR_ERR(t);
 	c = btrfs_buffer_node(t);
 	memset(c, 0, root->blocksize);
 	btrfs_set_header_nritems(&c->header, 1);
@@ -929,10 +968,15 @@ static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
 		    btrfs_header_nritems(&c->header) <
 		    BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
 			return 0;
+		if (ret < 0)
+			return ret;
 	}
 
 	c_nritems = btrfs_header_nritems(&c->header);
 	split_buffer = btrfs_alloc_free_block(trans, root, t->b_blocknr);
+	if (IS_ERR(split_buffer))
+		return PTR_ERR(split_buffer);
+
 	split = btrfs_buffer_node(split_buffer);
 	btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
 	btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
@@ -1022,6 +1066,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
 	struct btrfs_item *item;
 	u32 left_nritems;
 	u32 right_nritems;
+	int ret;
 
 	slot = path->slots[1];
 	if (!path->nodes[1]) {
@@ -1041,7 +1086,12 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
 		return 1;
 	}
 	/* cow and double check */
-	btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf);
+	ret = btrfs_cow_block(trans, root, right_buf, upper,
+			      slot + 1, &right_buf);
+	if (ret) {
+		btrfs_block_release(root, right_buf);
+		return 1;
+	}
 	right = btrfs_buffer_leaf(right_buf);
 	free_space = btrfs_leaf_free_space(root, right);
 	if (free_space < data_size + sizeof(struct btrfs_item)) {
@@ -1162,7 +1212,11 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
 	}
 
 	/* cow and double check */
-	btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
+	ret = btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
+	if (ret) {
+		/* we hit -ENOSPC, but it isn't fatal here */
+		return 1;
+	}
 	left = btrfs_buffer_leaf(t);
 	free_space = btrfs_leaf_free_space(root, left);
 	if (free_space < data_size + sizeof(struct btrfs_item)) {
@@ -1309,8 +1363,11 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
 	slot = path->slots[0];
 	nritems = btrfs_header_nritems(&l->header);
 	mid = (nritems + 1)/ 2;
+
 	right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr);
-	BUG_ON(!right_buffer);
+	if (IS_ERR(right_buffer))
+		return PTR_ERR(right_buffer);
+
 	right = btrfs_buffer_leaf(right_buffer);
 	memset(&right->header, 0, sizeof(right->header));
 	btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
@@ -1407,7 +1464,9 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
 	if (!double_split)
 		return ret;
 	right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr);
-	BUG_ON(!right_buffer);
+	if (IS_ERR(right_buffer))
+		return PTR_ERR(right_buffer);
+
 	right = btrfs_buffer_leaf(right_buffer);
 	memset(&right->header, 0, sizeof(right->header));
 	btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
@@ -1655,7 +1714,6 @@ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
 			     ptr, data, data_size);
 		btrfs_mark_buffer_dirty(path->nodes[0]);
 	}
-	btrfs_release_path(root, path);
 	btrfs_free_path(path);
 	return ret;
 }
@@ -1775,12 +1833,12 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 			slot = path->slots[1];
 			get_bh(leaf_buf);
 			wret = push_leaf_left(trans, root, path, 1);
-			if (wret < 0)
+			if (wret < 0 && wret != -ENOSPC)
 				ret = wret;
 			if (path->nodes[0] == leaf_buf &&
 			    btrfs_header_nritems(&leaf->header)) {
 				wret = push_leaf_right(trans, root, path, 1);
-				if (wret < 0)
+				if (wret < 0 && wret != -ENOSPC)
 					ret = wret;
 			}
 			if (btrfs_header_nritems(&leaf->header) == 0) {

fs/btrfs/ctree.h

@@ -1126,9 +1126,6 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  u64 objectid, u64 offset,
 			  char *data, size_t len);
-int btrfs_csum_verify_file_block(struct btrfs_root *root,
-				 u64 objectid, u64 offset,
-				 char *data, size_t len);
 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 					  struct btrfs_root *root,
 					  struct btrfs_path *path,

fs/btrfs/dir-item.c

@@ -47,6 +47,8 @@ static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
 		if (ret)
 			return ERR_PTR(ret);
 	}
+	if (ret < 0)
+		return ERR_PTR(ret);
 	WARN_ON(ret > 0);
 	leaf = btrfs_buffer_leaf(path->nodes[0]);
 	item = leaf->items + path->slots[0];
@@ -225,14 +227,13 @@ int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 	struct btrfs_leaf *leaf;
 	u32 sub_item_len;
 	u32 item_len;
-	int ret;
+	int ret = 0;
 
 	leaf = btrfs_buffer_leaf(path->nodes[0]);
 	sub_item_len = sizeof(*di) + btrfs_dir_name_len(di);
 	item_len = btrfs_item_size(leaf->items + path->slots[0]);
 	if (sub_item_len == btrfs_item_size(leaf->items + path->slots[0])) {
 		ret = btrfs_del_item(trans, root, path);
-		BUG_ON(ret);
 	} else {
 		char *ptr = (char *)di;
 		char *start = btrfs_item_ptr(leaf, path->slots[0], char);
@@ -240,7 +241,6 @@ int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 			item_len - (ptr + sub_item_len - start));
 		ret = btrfs_truncate_item(trans, root, path,
 					  item_len - sub_item_len);
-		BUG_ON(ret);
 	}
 	return 0;
 }

fs/btrfs/disk-io.c

@@ -580,7 +580,7 @@ int close_ctree(struct btrfs_root *root)
 	btrfs_transaction_flush_work(root);
 	mutex_lock(&fs_info->fs_mutex);
 	trans = btrfs_start_transaction(root, 1);
-	btrfs_commit_transaction(trans, root);
+	ret = btrfs_commit_transaction(trans, root);
 	/* run commit again to  drop the original snapshot */
 	trans = btrfs_start_transaction(root, 1);
 	btrfs_commit_transaction(trans, root);

fs/btrfs/extent-tree.c

@@ -100,6 +100,8 @@ static int cache_block_group(struct btrfs_root *root,
 		if (slot >= btrfs_header_nritems(&leaf->header)) {
 			reada_extent_leaves(root, path, limit);
 			ret = btrfs_next_leaf(root, path);
+			if (ret < 0)
+				goto err;
 			if (ret == 0) {
 				continue;
 			} else {
@@ -148,6 +150,7 @@ static int cache_block_group(struct btrfs_root *root,
 	}
 
 	block_group->cached = 1;
+err:
 	btrfs_free_path(path);
 	return 0;
 }
@@ -201,7 +204,9 @@ static u64 find_search_start(struct btrfs_root *root,
 		last = max(last, cache->last_prealloc);
 	}
 again:
-	cache_block_group(root, cache);
+	ret = cache_block_group(root, cache);
+	if (ret)
+		goto out;
 	while(1) {
 		ret = find_first_radix_bit(&root->fs_info->extent_map_radix,
 					   gang, last, ARRAY_SIZE(gang));
@@ -398,16 +403,23 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	struct btrfs_key ins;
 	u32 refs;
 
-	find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1, 0,
-			 &ins, 0);
 	path = btrfs_alloc_path();
-	BUG_ON(!path);
+	if (!path)
+		return -ENOMEM;
+	ret = find_free_extent(trans, root->fs_info->extent_root, 0, 0,
+			       (u64)-1, 0, &ins, 0);
+	if (ret) {
+		btrfs_free_path(path);
+		return ret;
+	}
 	key.objectid = blocknr;
 	key.flags = 0;
 	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 	key.offset = num_blocks;
 	ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 				0, 1);
+	if (ret < 0)
+		return ret;
 	if (ret != 0) {
 		BUG();
 	}
@@ -442,12 +454,14 @@ static int lookup_extent_ref(struct btrfs_trans_handle *trans,
 	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 	ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 				0, 0);
+	if (ret < 0)
+		goto out;
 	if (ret != 0)
 		BUG();
 	l = btrfs_buffer_leaf(path->nodes[0]);
 	item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 	*refs = btrfs_extent_refs(item);
-	btrfs_release_path(root->fs_info->extent_root, path);
+out:
 	btrfs_free_path(path);
 	return 0;
 }
@@ -469,6 +483,8 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	int i;
 	int leaf;
 	int ret;
+	int faili;
+	int err;
 
 	if (!root->ref_cows)
 		return 0;
@@ -491,14 +507,45 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 				continue;
 			ret = btrfs_inc_extent_ref(trans, root, disk_blocknr,
 				    btrfs_file_extent_disk_num_blocks(fi));
-			BUG_ON(ret);
+			if (ret) {
+				faili = i;
+				goto fail;
+			}
 		} else {
 			blocknr = btrfs_node_blockptr(buf_node, i);
 			ret = btrfs_inc_extent_ref(trans, root, blocknr, 1);
-			BUG_ON(ret);
+			if (ret) {
+				faili = i;
+				goto fail;
+			}
 		}
 	}
 	return 0;
+fail:
+	for (i =0; i < faili; i++) {
+		if (leaf) {
+			u64 disk_blocknr;
+			key = &buf_leaf->items[i].key;
+			if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
+				continue;
+			fi = btrfs_item_ptr(buf_leaf, i,
+					    struct btrfs_file_extent_item);
+			if (btrfs_file_extent_type(fi) ==
+			    BTRFS_FILE_EXTENT_INLINE)
+				continue;
+			disk_blocknr = btrfs_file_extent_disk_blocknr(fi);
+			if (disk_blocknr == 0)
+				continue;
+			err = btrfs_free_extent(trans, root, disk_blocknr,
+				    btrfs_file_extent_disk_num_blocks(fi), 0);
+			BUG_ON(err);
+		} else {
+			blocknr = btrfs_node_blockptr(buf_node, i);
+			err = btrfs_free_extent(trans, root, blocknr, 1, 0);
+			BUG_ON(err);
+		}
+	}
+	return ret;
 }
 
 static int write_one_cache_group(struct btrfs_trans_handle *trans,
@@ -512,15 +559,20 @@ static int write_one_cache_group(struct btrfs_trans_handle *trans,
 	struct btrfs_block_group_item *bi;
 	struct btrfs_key ins;
 
-	find_free_extent(trans, extent_root, 0, 0, (u64)-1, 0, &ins, 0);
+	ret = find_free_extent(trans, extent_root, 0, 0, (u64)-1, 0, &ins, 0);
+	/* FIXME, set bit to recalc cache groups on next mount */
+	if (ret)
+		return ret;
 	ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
+	if (ret < 0)
+		goto fail;
 	BUG_ON(ret);
 	bi = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
 			    struct btrfs_block_group_item);
 	memcpy(bi, &cache->item, sizeof(*bi));
 	mark_buffer_dirty(path->nodes[0]);
 	btrfs_release_path(extent_root, path);
-
+fail:
 	finish_current_insert(trans, extent_root);
 	pending_ret = del_pending_extents(trans, extent_root);
 	if (ret)
@@ -543,6 +595,7 @@ static int write_dirty_block_radix(struct btrfs_trans_handle *trans,
 	int werr = 0;
 	int i;
 	struct btrfs_path *path;
+	unsigned long off = 0;
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -550,18 +603,28 @@ static int write_dirty_block_radix(struct btrfs_trans_handle *trans,
 
 	while(1) {
 		ret = radix_tree_gang_lookup_tag(radix, (void **)cache,
-						 0, ARRAY_SIZE(cache),
+						 off, ARRAY_SIZE(cache),
 						 BTRFS_BLOCK_GROUP_DIRTY);
 		if (!ret)
 			break;
 		for (i = 0; i < ret; i++) {
-			radix_tree_tag_clear(radix, cache[i]->key.objectid +
-					     cache[i]->key.offset - 1,
-					     BTRFS_BLOCK_GROUP_DIRTY);
 			err = write_one_cache_group(trans, root,
 						    path, cache[i]);
-			if (err)
+			/*
+			 * if we fail to write the cache group, we want
+			 * to keep it marked dirty in hopes that a later
+			 * write will work
+			 */
+			if (err) {
 				werr = err;
+				off = cache[i]->key.objectid +
+					cache[i]->key.offset;
+				continue;
+			}
+
+			radix_tree_tag_clear(radix, cache[i]->key.objectid +
+					     cache[i]->key.offset - 1,
+					     BTRFS_BLOCK_GROUP_DIRTY);
 		}
 	}
 	btrfs_free_path(path);
@@ -801,14 +864,20 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 	key.offset = num_blocks;
 
-	find_free_extent(trans, root, 0, 0, (u64)-1, 0, &ins, 0);
 	path = btrfs_alloc_path();
-	BUG_ON(!path);
+	if (!path)
+		return -ENOMEM;
 
-	ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
+	ret = find_free_extent(trans, root, 0, 0, (u64)-1, 0, &ins, 0);
 	if (ret) {
-		BUG();
+		btrfs_free_path(path);
+		return ret;
 	}
+
+	ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
+	if (ret < 0)
+		return ret;
+	BUG_ON(ret);
 	ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
 			    struct btrfs_extent_item);
 	BUG_ON(ei->refs == 0);
@@ -827,8 +896,9 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 		btrfs_set_super_blocks_used(info->disk_super,
 					    super_blocks_used - num_blocks);
 		ret = btrfs_del_item(trans, extent_root, path);
-		if (ret)
-			BUG();
+		if (ret) {
+			return ret;
+		}
 		ret = update_block_group(trans, root, blocknr, num_blocks, 0,
 					 mark_free, 0);
 		BUG_ON(ret);
@@ -1075,7 +1145,6 @@ next:
 		path->slots[0]++;
 		cond_resched();
 	}
-	// FIXME -ENOSPC
 check_pending:
 	/* we have to make sure we didn't find an extent that has already
 	 * been allocated by the map tree or the original allocation
@@ -1246,7 +1315,15 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 	ret = find_free_extent(trans, root, num_blocks, search_start,
 			       search_end, hint_block, ins, data);
 	if (ret) {
-		return ret;
+		if (search_start == 0)
+			return ret;
+		search_end = search_start - 1;
+		search_start = 0;
+		hint_block = search_start;
+		ret = find_free_extent(trans, root, num_blocks, search_start,
+				       search_end, hint_block, ins, data);
+		if (ret)
+			return ret;
 	}
 
 	/*
@@ -1271,7 +1348,16 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 				       search_end, hint_block,
 				       &prealloc_key, 0);
 		if (ret) {
-			return ret;
+			if (search_start == 0)
+				return ret;
+			search_end = search_start - 1;
+			search_start = 0;
+			hint_block = search_start;
+			ret = find_free_extent(trans, root, 0, search_start,
+					       search_end, hint_block,
+					       &prealloc_key, 0);
+			if (ret)
+				return ret;
 		}
 	}
 
@@ -1309,11 +1395,14 @@ struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 	ret = btrfs_alloc_extent(trans, root, root->root_key.objectid,
 				 1, hint, (unsigned long)-1, &ins, 0);
 	if (ret) {
-		BUG();
-		return NULL;
+		BUG_ON(ret > 0);
+		return ERR_PTR(ret);
 	}
-	BUG_ON(ret);
 	buf = btrfs_find_create_tree_block(root, ins.objectid);
+	if (!buf) {
+		btrfs_free_extent(trans, root, ins.objectid, 1, 0);
+		return ERR_PTR(-ENOMEM);
+	}
 	set_buffer_uptodate(buf);
 	set_buffer_checked(buf);
 	set_radix_bit(&trans->transaction->dirty_pages, buf->b_page->index);

fs/btrfs/file-item.c

@@ -45,6 +45,8 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 
 	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 				      sizeof(*item));
+	if (ret < 0)
+		goto out;
 	BUG_ON(ret);
 	item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
 			      struct btrfs_file_extent_item);
@@ -55,10 +57,9 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 	btrfs_set_file_extent_generation(item, trans->transid);
 	btrfs_set_file_extent_type(item, BTRFS_FILE_EXTENT_REG);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
-
-	btrfs_release_path(root, path);
+out:
 	btrfs_free_path(path);
-	return 0;
+	return ret;
 }
 
 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
@@ -213,6 +214,8 @@ insert:
 	csum_offset = 0;
 	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 				      BTRFS_CRC32_SIZE);
+	if (ret < 0)
+		goto fail;
 	if (ret != 0) {
 		WARN_ON(1);
 		goto fail;
@@ -261,40 +264,3 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-int btrfs_csum_verify_file_block(struct btrfs_root *root,
-				 u64 objectid, u64 offset,
-				 char *data, size_t len)
-{
-	int ret;
-	struct btrfs_key file_key;
-	struct btrfs_path *path;
-	struct btrfs_csum_item *item;
-	char result[BTRFS_CRC32_SIZE];
-
-	path = btrfs_alloc_path();
-	BUG_ON(!path);
-	file_key.objectid = objectid;
-	file_key.offset = offset;
-	file_key.flags = 0;
-	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
-	mutex_lock(&root->fs_info->fs_mutex);
-
-	item = btrfs_lookup_csum(NULL, root, path, objectid, offset, 0);
-	if (IS_ERR(item)) {
-		ret = PTR_ERR(item);
-		/* a csum that isn't present is a preallocated region. */
-		if (ret == -ENOENT || ret == -EFBIG)
-			ret = -ENOENT;
-		goto fail;
-	}
-
-	ret = btrfs_csum_data(root, data, len, result);
-	WARN_ON(ret);
-	if (memcmp(result, &item->csum, BTRFS_CRC32_SIZE))
-		ret = 1;
-fail:
-	btrfs_release_path(root, path);
-	btrfs_free_path(path);
-	mutex_unlock(&root->fs_info->fs_mutex);
-	return ret;
-}

fs/btrfs/file.c

@@ -81,6 +81,62 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages)
 	}
 }
 
+static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
+				u64 offset, ssize_t size,
+				struct buffer_head *bh)
+{
+	struct btrfs_key key;
+	struct btrfs_path *path;
+	char *ptr, *kaddr;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_file_extent_item *ei;
+	u32 datasize;
+	int err = 0;
+	int ret;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	mutex_lock(&root->fs_info->fs_mutex);
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, inode);
+
+	key.objectid = inode->i_ino;
+	key.offset = offset;
+	key.flags = 0;
+	btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
+	BUG_ON(size >= PAGE_CACHE_SIZE);
+	datasize = btrfs_file_extent_calc_inline_size(size);
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key,
+				      datasize);
+	if (ret) {
+		err = ret;
+		goto fail;
+	}
+	ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+	       path->slots[0], struct btrfs_file_extent_item);
+	btrfs_set_file_extent_generation(ei, trans->transid);
+	btrfs_set_file_extent_type(ei,
+				   BTRFS_FILE_EXTENT_INLINE);
+	ptr = btrfs_file_extent_inline_start(ei);
+
+	kaddr = kmap_atomic(bh->b_page, KM_USER0);
+	btrfs_memcpy(root, path->nodes[0]->b_data,
+		     ptr, kaddr + bh_offset(bh),
+		     size);
+	kunmap_atomic(kaddr, KM_USER0);
+	mark_buffer_dirty(path->nodes[0]);
+fail:
+	btrfs_free_path(path);
+	ret = btrfs_end_transaction(trans, root);
+	if (ret && !err)
+		err = ret;
+	mutex_unlock(&root->fs_info->fs_mutex);
+	return err;
+}
+
 static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
 				   struct btrfs_root *root,
 				   struct file *file,
@@ -96,57 +152,22 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
 	int this_write;
 	struct inode *inode = file->f_path.dentry->d_inode;
 	struct buffer_head *bh;
-	struct btrfs_file_extent_item *ei;
 
 	for (i = 0; i < num_pages; i++) {
 		offset = pos & (PAGE_CACHE_SIZE -1);
 		this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
-		/* FIXME, one block at a time */
 
+		/* FIXME, one block at a time */
 		bh = page_buffers(pages[i]);
 
 		if (buffer_mapped(bh) && bh->b_blocknr == 0) {
-			struct btrfs_key key;
-			struct btrfs_path *path;
-			char *ptr, *kaddr;
-			u32 datasize;
-
-			mutex_lock(&root->fs_info->fs_mutex);
-			trans = btrfs_start_transaction(root, 1);
-			btrfs_set_trans_block_group(trans, inode);
-
-			/* create an inline extent, and copy the data in */
-			path = btrfs_alloc_path();
-			BUG_ON(!path);
-			key.objectid = inode->i_ino;
-			key.offset = pages[i]->index << PAGE_CACHE_SHIFT;
-			key.flags = 0;
-			btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
-			BUG_ON(write_bytes >= PAGE_CACHE_SIZE);
-			datasize = offset +
-				btrfs_file_extent_calc_inline_size(write_bytes);
-
-			ret = btrfs_insert_empty_item(trans, root, path, &key,
-						      datasize);
-			BUG_ON(ret);
-			ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
-			       path->slots[0], struct btrfs_file_extent_item);
-			btrfs_set_file_extent_generation(ei, trans->transid);
-			btrfs_set_file_extent_type(ei,
-						   BTRFS_FILE_EXTENT_INLINE);
-			ptr = btrfs_file_extent_inline_start(ei);
-
-			kaddr = kmap_atomic(bh->b_page, KM_USER0);
-			btrfs_memcpy(root, path->nodes[0]->b_data,
-				     ptr, kaddr + bh_offset(bh),
-				     offset + write_bytes);
-			kunmap_atomic(kaddr, KM_USER0);
-
-			mark_buffer_dirty(path->nodes[0]);
-			btrfs_free_path(path);
-			ret = btrfs_end_transaction(trans, root);
-			BUG_ON(ret);
-			mutex_unlock(&root->fs_info->fs_mutex);
+			ret = insert_inline_extent(root, inode,
+					pages[i]->index << PAGE_CACHE_SHIFT,
+					offset + this_write, bh);
+			if (ret) {
+				err = ret;
+				goto failed;
+			}
 		}
 
 		ret = btrfs_commit_write(file, pages[i], offset,
@@ -321,6 +342,7 @@ next_slot:
 					btrfs_file_extent_disk_blocknr(extent);
 			}
 			ret = btrfs_del_item(trans, root, path);
+			/* TODO update progress marker and return */
 			BUG_ON(ret);
 			btrfs_release_path(root, path);
 			extent = NULL;
@@ -452,7 +474,8 @@ static int prepare_pages(struct btrfs_root *root,
 		err = btrfs_drop_extents(trans, root, inode,
 			 start_pos, (pos + write_bytes + root->blocksize -1) &
 			 ~((u64)root->blocksize - 1), &hint_block);
-		BUG_ON(err);
+		if (err)
+			goto failed_release;
 	}
 
 	/* insert any holes we need to create */
@@ -469,7 +492,8 @@ static int prepare_pages(struct btrfs_root *root,
 						       last_pos_in_file,
 						       0, 0, hole_size);
 		}
-		BUG_ON(err);
+		if (err)
+			goto failed_release;
 	}
 
 	/*
@@ -481,11 +505,13 @@ static int prepare_pages(struct btrfs_root *root,
 		err = btrfs_alloc_extent(trans, root, inode->i_ino,
 					 num_blocks, hint_block, (u64)-1,
 					 &ins, 1);
-		BUG_ON(err);
+		if (err)
+			goto failed_truncate;
 		err = btrfs_insert_file_extent(trans, root, inode->i_ino,
 				       start_pos, ins.objectid, ins.offset,
 				       ins.offset);
-		BUG_ON(err);
+		if (err)
+			goto failed_truncate;
 	} else {
 		ins.offset = 0;
 		ins.objectid = 0;
@@ -618,16 +644,21 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 		ret = prepare_pages(root, file, pages, num_pages,
 				    pos, first_index, last_index,
 				    write_bytes);
-		BUG_ON(ret);
+		if (ret)
+			goto out;
 
 		ret = btrfs_copy_from_user(pos, num_pages,
 					   write_bytes, pages, buf);
-		BUG_ON(ret);
+		if (ret) {
+			btrfs_drop_pages(pages, num_pages);
+			goto out;
+		}
 
 		ret = dirty_and_release_pages(NULL, root, file, pages,
 					      num_pages, pos, write_bytes);
-		BUG_ON(ret);
 		btrfs_drop_pages(pages, num_pages);
+		if (ret)
+			goto out;
 
 		buf += write_bytes;
 		count -= write_bytes;

fs/btrfs/inode.c

@@ -212,7 +212,11 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
 	struct btrfs_dir_item *di;
 
 	path = btrfs_alloc_path();
-	BUG_ON(!path);
+	if (!path) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
 	di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
 				    name, name_len, -1);
 	if (IS_ERR(di)) {
@@ -225,7 +229,8 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
 	}
 	objectid = btrfs_disk_key_objectid(&di->location);
 	ret = btrfs_delete_one_dir_name(trans, root, path, di);
-	BUG_ON(ret);
+	if (ret)
+		goto err;
 	btrfs_release_path(root, path);
 
 	di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
@@ -239,7 +244,6 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
 		goto err;
 	}
 	ret = btrfs_delete_one_dir_name(trans, root, path, di);
-	BUG_ON(ret);
 
 	dentry->d_inode->i_ctime = dir->i_ctime;
 err:
@@ -248,7 +252,7 @@ err:
 		dir->i_size -= name_len * 2;
 		btrfs_update_inode(trans, root, dir);
 		drop_nlink(dentry->d_inode);
-		btrfs_update_inode(trans, root, dentry->d_inode);
+		ret = btrfs_update_inode(trans, root, dentry->d_inode);
 		dir->i_sb->s_dirt = 1;
 	}
 	return ret;
@@ -359,9 +363,10 @@ static int btrfs_free_inode(struct btrfs_trans_handle *trans,
 	BUG_ON(!path);
 	ret = btrfs_lookup_inode(trans, root, path,
 				 &BTRFS_I(inode)->location, -1);
-	BUG_ON(ret);
-	ret = btrfs_del_item(trans, root, path);
-	BUG_ON(ret);
+	if (ret > 0)
+		ret = -ENOENT;
+	if (!ret)
+		ret = btrfs_del_item(trans, root, path);
 	btrfs_free_path(path);
 	return ret;
 }
@@ -516,7 +521,8 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
 		}
 		if (del_item) {
 			ret = btrfs_del_item(trans, root, path);
-			BUG_ON(ret);
+			if (ret)
+				goto error;
 		} else {
 			break;
 		}
@@ -577,19 +583,22 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
 				 page->index << PAGE_CACHE_SHIFT,
 				 (page->index + 1) << PAGE_CACHE_SHIFT,
 				 &alloc_hint);
-	BUG_ON(ret);
+	if (ret)
+		goto out;
 	ret = btrfs_alloc_extent(trans, root, inode->i_ino, 1,
 				 alloc_hint, (u64)-1, &ins, 1);
-	BUG_ON(ret);
+	if (ret)
+		goto out;
 	ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
 				       page->index << PAGE_CACHE_SHIFT,
 				       ins.objectid, 1, 1);
-	BUG_ON(ret);
+	if (ret)
+		goto out;
 	SetPageChecked(page);
 	kaddr = kmap(page);
 	memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
 	flush_dcache_page(page);
-	btrfs_csum_file_block(trans, root, inode->i_ino,
+	ret = btrfs_csum_file_block(trans, root, inode->i_ino,
 			      page->index << PAGE_CACHE_SHIFT,
 			      kaddr, PAGE_CACHE_SIZE);
 	kunmap(page);
@@ -633,9 +642,10 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
 		btrfs_set_trans_block_group(trans, inode);
 		err = btrfs_insert_file_extent(trans, root, inode->i_ino,
 					       pos, 0, 0, hole_size);
-		BUG_ON(err);
 		btrfs_end_transaction(trans, root);
 		mutex_unlock(&root->fs_info->fs_mutex);
+		if (err)
+			return err;
 	}
 out:
 	err = inode_setattr(inode, attr);
@@ -657,12 +667,20 @@ void btrfs_delete_inode(struct inode *inode)
 	trans = btrfs_start_transaction(root, 1);
 	btrfs_set_trans_block_group(trans, inode);
 	ret = btrfs_truncate_in_trans(trans, root, inode);
-	BUG_ON(ret);
-	btrfs_free_inode(trans, root, inode);
+	if (ret)
+		goto no_delete_lock;
+	ret = btrfs_free_inode(trans, root, inode);
+	if (ret)
+		goto no_delete_lock;
 	btrfs_end_transaction(trans, root);
 	mutex_unlock(&root->fs_info->fs_mutex);
 	btrfs_btree_balance_dirty(root);
 	return;
+
+no_delete_lock:
+	btrfs_end_transaction(trans, root);
+	mutex_unlock(&root->fs_info->fs_mutex);
+	btrfs_btree_balance_dirty(root);
 no_delete:
 	clear_inode(inode);
 }
@@ -946,7 +964,7 @@ int btrfs_write_inode(struct inode *inode, int wait)
 }
 
 /*
- * This is somewhat expense, updating the tree every time the
+ * This is somewhat expensive, updating the tree every time the
  * inode changes.  But, it is most likely to find the inode in cache.
  * FIXME, needs more benchmarking...there are no reasons other than performance
  * to keep or drop this code.
@@ -1002,8 +1020,8 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
 	btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
 
 	ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
-	BUG_ON(ret);
-
+	if (ret)
+		return ERR_PTR(ret);
 	insert_inode_hash(inode);
 	return inode;
 }
@@ -1121,7 +1139,9 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 		drop_inode = 1;
 	dir->i_sb->s_dirt = 1;
 	btrfs_update_inode_block_group(trans, dir);
-	btrfs_update_inode(trans, root, inode);
+	err = btrfs_update_inode(trans, root, inode);
+	if (err)
+		drop_inode = 1;
 
 	btrfs_end_transaction(trans, root);
 	mutex_unlock(&root->fs_info->fs_mutex);
@@ -1349,17 +1369,26 @@ not_found:
 		ret = btrfs_alloc_extent(trans, root, inode->i_ino,
 					 1, alloc_hint, (u64)-1,
 					 &ins, 1);
-		BUG_ON(ret);
+		if (ret) {
+			err = ret;
+			goto out;
+		}
 		ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
 					       iblock << inode->i_blkbits,
 					       ins.objectid, ins.offset,
 					       ins.offset);
-		BUG_ON(ret);
+		if (ret) {
+			err = ret;
+			goto out;
+		}
 		btrfs_map_bh_to_logical(root, result, ins.objectid);
 	}
 out:
-	if (trans)
-		err = btrfs_end_transaction(trans, root);
+	if (trans) {
+		ret = btrfs_end_transaction(trans, root);
+		if (!err)
+			err = ret;
+	}
 	btrfs_free_path(path);
 	return err;
 }
@@ -1375,8 +1404,8 @@ int btrfs_get_block(struct inode *inode, sector_t iblock,
 	return err;
 }
 
-int btrfs_get_block_csum(struct inode *inode, sector_t iblock,
-		    struct buffer_head *result, int create)
+static int btrfs_get_block_csum(struct inode *inode, sector_t iblock,
+				struct buffer_head *result, int create)
 {
 	int ret;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -1397,7 +1426,7 @@ int btrfs_get_block_csum(struct inode *inode, sector_t iblock,
 		/* a csum that isn't present is a preallocated region. */
 		if (ret == -ENOENT || ret == -EFBIG)
 			ret = 0;
-		result->b_private = 0;
+		result->b_private = NULL;
 		goto out;
 	}
 	memcpy((char *)&result->b_private, &item->csum, BTRFS_CRC32_SIZE);
@@ -1736,11 +1765,10 @@ static int __btrfs_write_full_page(struct inode *inode, struct page *page,
 			trans = btrfs_start_transaction(root, 1);
 			btrfs_set_trans_block_group(trans, inode);
 			kaddr = kmap(page);
-			ret = btrfs_csum_file_block(trans, root, inode->i_ino,
+			btrfs_csum_file_block(trans, root, inode->i_ino,
 						    off, kaddr + bh_offset(bh),
 						    bh->b_size);
 			kunmap(page);
-			BUG_ON(ret);
 			ret = btrfs_end_transaction(trans, root);
 			BUG_ON(ret);
 			mutex_unlock(&root->fs_info->fs_mutex);
@@ -1930,7 +1958,6 @@ static void btrfs_truncate(struct inode *inode)
 
 	/* FIXME, add redo link to tree so we don't leak on crash */
 	ret = btrfs_truncate_in_trans(trans, root, inode);
-	BUG_ON(ret);
 	btrfs_update_inode(trans, root, inode);
 	ret = btrfs_end_transaction(trans, root);
 	BUG_ON(ret);
@@ -1970,6 +1997,7 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
 	struct inode *inode;
 	struct inode *dir;
 	int ret;
+	int err;
 	u64 objectid;
 	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 
@@ -1978,8 +2006,8 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
 	BUG_ON(!trans);
 
 	subvol = btrfs_alloc_free_block(trans, root, 0);
-	if (subvol == NULL)
-		return -ENOSPC;
+	if (IS_ERR(subvol))
+		return PTR_ERR(subvol);
 	leaf = btrfs_buffer_leaf(subvol);
 	btrfs_set_header_nritems(&leaf->header, 0);
 	btrfs_set_header_level(&leaf->header, 0);
@@ -2005,7 +2033,8 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
 
 	ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
 				       0, &objectid);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	btrfs_set_root_dirid(&root_item, new_dirid);
 
@@ -2015,7 +2044,8 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
 	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 				&root_item);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	/*
 	 * insert the directory item
@@ -2025,10 +2055,12 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
 	ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 				    name, namelen, dir->i_ino, &key,
 				    BTRFS_FT_DIR);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	ret = btrfs_commit_transaction(trans, root);
-	BUG_ON(ret);
+	if (ret)
+		goto fail_commit;
 
 	new_root = btrfs_read_fs_root(root->fs_info, &key);
 	BUG_ON(!new_root);
@@ -2038,24 +2070,29 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
 
 	inode = btrfs_new_inode(trans, new_root, new_dirid,
 				BTRFS_I(dir)->block_group, S_IFDIR | 0700);
+	if (IS_ERR(inode))
+		goto fail;
 	inode->i_op = &btrfs_dir_inode_operations;
 	inode->i_fop = &btrfs_dir_file_operations;
 	new_root->inode = inode;
 
 	ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	inode->i_nlink = 1;
 	inode->i_size = 6;
 	ret = btrfs_update_inode(trans, new_root, inode);
-	BUG_ON(ret);
-
-	ret = btrfs_commit_transaction(trans, new_root);
-	BUG_ON(ret);
-
+	if (ret)
+		goto fail;
+fail:
+	err = btrfs_commit_transaction(trans, root);
+	if (err && !ret)
+		ret = err;
+fail_commit:
 	mutex_unlock(&root->fs_info->fs_mutex);
 	btrfs_btree_balance_dirty(root);
-	return 0;
+	return ret;
 }
 
 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
@@ -2064,6 +2101,7 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 	struct btrfs_key key;
 	struct btrfs_root_item new_root_item;
 	int ret;
+	int err;
 	u64 objectid;
 
 	if (!root->ref_cows)
@@ -2074,11 +2112,13 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 	BUG_ON(!trans);
 
 	ret = btrfs_update_inode(trans, root, root->inode);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
 				       0, &objectid);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	memcpy(&new_root_item, &root->root_item,
 	       sizeof(new_root_item));
@@ -2091,7 +2131,8 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 
 	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 				&new_root_item);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	/*
 	 * insert the directory item
@@ -2102,16 +2143,20 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 				    root->fs_info->sb->s_root->d_inode->i_ino,
 				    &key, BTRFS_FT_DIR);
 
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
 	ret = btrfs_inc_root_ref(trans, root);
-	BUG_ON(ret);
+	if (ret)
+		goto fail;
 
-	ret = btrfs_commit_transaction(trans, root);
-	BUG_ON(ret);
+fail:
+	err = btrfs_commit_transaction(trans, root);
+	if (err && !ret)
+		ret = err;
 	mutex_unlock(&root->fs_info->fs_mutex);
 	btrfs_btree_balance_dirty(root);
-	return 0;
+	return ret;
 }
 
 int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
@@ -2148,12 +2193,13 @@ int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
 		btrfs_free_path(path);
 		if (di && !IS_ERR(di))
 			return -EEXIST;
+		if (IS_ERR(di))
+			return PTR_ERR(di);
 
 		if (root == root->fs_info->tree_root)
 			ret = create_subvol(root, vol_args.name, namelen);
 		else
 			ret = create_snapshot(root, vol_args.name, namelen);
-		WARN_ON(ret);
 		break;
 	default:
 		return -ENOTTY;
@@ -2316,7 +2362,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
 		old_parent_oid = btrfs_disk_key_objectid(&di->location);
 		ret = btrfs_del_item(trans, root, path);
 		if (ret) {
-			ret = -EIO;
 			goto out_fail;
 		}
 		btrfs_release_path(root, path);
@@ -2335,7 +2380,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
 		}
 		ret = btrfs_del_item(trans, root, path);
 		if (ret) {
-			ret = -EIO;
 			goto out_fail;
 		}
 		btrfs_release_path(root, path);
@@ -2361,7 +2405,9 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
 			clear_nlink(new_inode);
 		else
 			drop_nlink(new_inode);
-		btrfs_update_inode(trans, root, new_inode);
+		ret = btrfs_update_inode(trans, root, new_inode);
+		if (ret)
+			goto out_fail;
 	}
 	ret = btrfs_add_link(trans, new_dentry, old_inode);
 	if (ret)
@@ -2433,7 +2479,10 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 	datasize = btrfs_file_extent_calc_inline_size(name_len);
 	err = btrfs_insert_empty_item(trans, root, path, &key,
 				      datasize);
-	BUG_ON(err);
+	if (err) {
+		drop_inode = 1;
+		goto out_unlock;
+	}
 	ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
 	       path->slots[0], struct btrfs_file_extent_item);
 	btrfs_set_file_extent_generation(ei, trans->transid);
@@ -2447,13 +2496,13 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 	inode->i_op = &btrfs_symlink_inode_operations;
 	inode->i_mapping->a_ops = &btrfs_symlink_aops;
 	inode->i_size = name_len - 1;
-	btrfs_update_inode(trans, root, inode);
-	err = 0;
+	err = btrfs_update_inode(trans, root, inode);
+	if (err)
+		drop_inode = 1;
 
 out_unlock:
 	btrfs_end_transaction(trans, root);
 	mutex_unlock(&root->fs_info->fs_mutex);
-
 	if (drop_inode) {
 		inode_dec_link_count(inode);
 		iput(inode);

fs/btrfs/root-tree.c

@@ -90,7 +90,6 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
 {
 	int ret;
 	ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
-	BUG_ON(ret);
 	return ret;
 }
 

fs/btrfs/super.c

@@ -125,9 +125,8 @@ static int btrfs_sync_fs(struct super_block *sb, int wait)
 	trans = btrfs_start_transaction(root, 1);
 	ret = btrfs_commit_transaction(trans, root);
 	sb->s_dirt = 0;
-	BUG_ON(ret);
 	mutex_unlock(&root->fs_info->fs_mutex);
-	return 0;
+	return ret;
 }
 
 static void btrfs_write_super(struct super_block *sb)

fs/btrfs/transaction.c

@@ -219,7 +219,8 @@ static int add_dirty_roots(struct btrfs_trans_handle *trans,
 	struct btrfs_root *root;
 	int i;
 	int ret;
-	int err;
+	int err = 0;
+
 	while(1) {
 		ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 						 ARRAY_SIZE(gang),
@@ -251,11 +252,12 @@ static int add_dirty_roots(struct btrfs_trans_handle *trans,
 			err = btrfs_insert_root(trans, root->fs_info->tree_root,
 						&root->root_key,
 						&root->root_item);
-			BUG_ON(err);
+			if (err)
+				break;
 			list_add(&dirty->list, list);
 		}
 	}
-	return 0;
+	return err;
 }
 
 static int drop_dirty_roots(struct btrfs_root *tree_root,
@@ -263,7 +265,7 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
 {
 	struct dirty_root *dirty;
 	struct btrfs_trans_handle *trans;
-	int ret;
+	int ret = 0;
 	while(!list_empty(list)) {
 		mutex_lock(&tree_root->fs_info->fs_mutex);
 		dirty = list_entry(list->next, struct dirty_root, list);
@@ -274,14 +276,15 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
 		BUG_ON(ret);
 
 		ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
-		BUG_ON(ret);
+		if (ret)
+			break;
 		ret = btrfs_end_transaction(trans, tree_root);
 		BUG_ON(ret);
 		kfree(dirty);
 		mutex_unlock(&tree_root->fs_info->fs_mutex);
 		btrfs_btree_balance_dirty(tree_root);
 	}
-	return 0;
+	return ret;
 }
 
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
@@ -321,9 +324,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 	}
 	finish_wait(&trans->transaction->writer_wait, &wait);
 	WARN_ON(cur_trans != trans->transaction);
-	add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
+	ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
+			      &dirty_fs_roots);
+	BUG_ON(ret);
+
 	ret = btrfs_commit_tree_roots(trans, root);
 	BUG_ON(ret);
+
 	cur_trans = root->fs_info->running_transaction;
 	root->fs_info->running_transaction = NULL;
 	if (cur_trans->list.prev != &root->fs_info->trans_list) {