1/*
2 * Copyright (C) STRATO AG 2013.  All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18#include <linux/uuid.h>
19#include <asm/unaligned.h>
20#include "ctree.h"
21#include "transaction.h"
22#include "disk-io.h"
23#include "print-tree.h"
24
25
26static void btrfs_uuid_to_key(u8 *uuid, u8 type, struct btrfs_key *key)
27{
28	key->type = type;
29	key->objectid = get_unaligned_le64(uuid);
30	key->offset = get_unaligned_le64(uuid + sizeof(u64));
31}
32
33/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
34static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
35				  u8 type, u64 subid)
36{
37	int ret;
38	struct btrfs_path *path = NULL;
39	struct extent_buffer *eb;
40	int slot;
41	u32 item_size;
42	unsigned long offset;
43	struct btrfs_key key;
44
45	if (WARN_ON_ONCE(!uuid_root)) {
46		ret = -ENOENT;
47		goto out;
48	}
49
50	path = btrfs_alloc_path();
51	if (!path) {
52		ret = -ENOMEM;
53		goto out;
54	}
55
56	btrfs_uuid_to_key(uuid, type, &key);
57	ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
58	if (ret < 0) {
59		goto out;
60	} else if (ret > 0) {
61		ret = -ENOENT;
62		goto out;
63	}
64
65	eb = path->nodes[0];
66	slot = path->slots[0];
67	item_size = btrfs_item_size_nr(eb, slot);
68	offset = btrfs_item_ptr_offset(eb, slot);
69	ret = -ENOENT;
70
71	if (!IS_ALIGNED(item_size, sizeof(u64))) {
72		btrfs_warn(uuid_root->fs_info, "uuid item with illegal size %lu!",
73			(unsigned long)item_size);
74		goto out;
75	}
76	while (item_size) {
77		__le64 data;
78
79		read_extent_buffer(eb, &data, offset, sizeof(data));
80		if (le64_to_cpu(data) == subid) {
81			ret = 0;
82			break;
83		}
84		offset += sizeof(data);
85		item_size -= sizeof(data);
86	}
87
88out:
89	btrfs_free_path(path);
90	return ret;
91}
92
93int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans,
94			struct btrfs_root *uuid_root, u8 *uuid, u8 type,
95			u64 subid_cpu)
96{
97	int ret;
98	struct btrfs_path *path = NULL;
99	struct btrfs_key key;
100	struct extent_buffer *eb;
101	int slot;
102	unsigned long offset;
103	__le64 subid_le;
104
105	ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
106	if (ret != -ENOENT)
107		return ret;
108
109	if (WARN_ON_ONCE(!uuid_root)) {
110		ret = -EINVAL;
111		goto out;
112	}
113
114	btrfs_uuid_to_key(uuid, type, &key);
115
116	path = btrfs_alloc_path();
117	if (!path) {
118		ret = -ENOMEM;
119		goto out;
120	}
121
122	ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
123				      sizeof(subid_le));
124	if (ret >= 0) {
125		/* Add an item for the type for the first time */
126		eb = path->nodes[0];
127		slot = path->slots[0];
128		offset = btrfs_item_ptr_offset(eb, slot);
129	} else if (ret == -EEXIST) {
130		/*
131		 * An item with that type already exists.
132		 * Extend the item and store the new subid at the end.
133		 */
134		btrfs_extend_item(uuid_root, path, sizeof(subid_le));
135		eb = path->nodes[0];
136		slot = path->slots[0];
137		offset = btrfs_item_ptr_offset(eb, slot);
138		offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le);
139	} else if (ret < 0) {
140		btrfs_warn(uuid_root->fs_info, "insert uuid item failed %d "
141			"(0x%016llx, 0x%016llx) type %u!",
142			ret, (unsigned long long)key.objectid,
143			(unsigned long long)key.offset, type);
144		goto out;
145	}
146
147	ret = 0;
148	subid_le = cpu_to_le64(subid_cpu);
149	write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
150	btrfs_mark_buffer_dirty(eb);
151
152out:
153	btrfs_free_path(path);
154	return ret;
155}
156
157int btrfs_uuid_tree_rem(struct btrfs_trans_handle *trans,
158			struct btrfs_root *uuid_root, u8 *uuid, u8 type,
159			u64 subid)
160{
161	int ret;
162	struct btrfs_path *path = NULL;
163	struct btrfs_key key;
164	struct extent_buffer *eb;
165	int slot;
166	unsigned long offset;
167	u32 item_size;
168	unsigned long move_dst;
169	unsigned long move_src;
170	unsigned long move_len;
171
172	if (WARN_ON_ONCE(!uuid_root)) {
173		ret = -EINVAL;
174		goto out;
175	}
176
177	btrfs_uuid_to_key(uuid, type, &key);
178
179	path = btrfs_alloc_path();
180	if (!path) {
181		ret = -ENOMEM;
182		goto out;
183	}
184
185	ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
186	if (ret < 0) {
187		btrfs_warn(uuid_root->fs_info, "error %d while searching for uuid item!",
188			ret);
189		goto out;
190	}
191	if (ret > 0) {
192		ret = -ENOENT;
193		goto out;
194	}
195
196	eb = path->nodes[0];
197	slot = path->slots[0];
198	offset = btrfs_item_ptr_offset(eb, slot);
199	item_size = btrfs_item_size_nr(eb, slot);
200	if (!IS_ALIGNED(item_size, sizeof(u64))) {
201		btrfs_warn(uuid_root->fs_info, "uuid item with illegal size %lu!",
202			(unsigned long)item_size);
203		ret = -ENOENT;
204		goto out;
205	}
206	while (item_size) {
207		__le64 read_subid;
208
209		read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
210		if (le64_to_cpu(read_subid) == subid)
211			break;
212		offset += sizeof(read_subid);
213		item_size -= sizeof(read_subid);
214	}
215
216	if (!item_size) {
217		ret = -ENOENT;
218		goto out;
219	}
220
221	item_size = btrfs_item_size_nr(eb, slot);
222	if (item_size == sizeof(subid)) {
223		ret = btrfs_del_item(trans, uuid_root, path);
224		goto out;
225	}
226
227	move_dst = offset;
228	move_src = offset + sizeof(subid);
229	move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
230	memmove_extent_buffer(eb, move_dst, move_src, move_len);
231	btrfs_truncate_item(uuid_root, path, item_size - sizeof(subid), 1);
232
233out:
234	btrfs_free_path(path);
235	return ret;
236}
237
238static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
239			       u64 subid)
240{
241	struct btrfs_trans_handle *trans;
242	int ret;
243
244	/* 1 - for the uuid item */
245	trans = btrfs_start_transaction(uuid_root, 1);
246	if (IS_ERR(trans)) {
247		ret = PTR_ERR(trans);
248		goto out;
249	}
250
251	ret = btrfs_uuid_tree_rem(trans, uuid_root, uuid, type, subid);
252	btrfs_end_transaction(trans, uuid_root);
253
254out:
255	return ret;
256}
257
258int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info,
259			    int (*check_func)(struct btrfs_fs_info *, u8 *, u8,
260					      u64))
261{
262	struct btrfs_root *root = fs_info->uuid_root;
263	struct btrfs_key key;
264	struct btrfs_path *path;
265	int ret = 0;
266	struct extent_buffer *leaf;
267	int slot;
268	u32 item_size;
269	unsigned long offset;
270
271	path = btrfs_alloc_path();
272	if (!path) {
273		ret = -ENOMEM;
274		goto out;
275	}
276
277	key.objectid = 0;
278	key.type = 0;
279	key.offset = 0;
280
281again_search_slot:
282	ret = btrfs_search_forward(root, &key, path, 0);
283	if (ret) {
284		if (ret > 0)
285			ret = 0;
286		goto out;
287	}
288
289	while (1) {
290		cond_resched();
291		leaf = path->nodes[0];
292		slot = path->slots[0];
293		btrfs_item_key_to_cpu(leaf, &key, slot);
294
295		if (key.type != BTRFS_UUID_KEY_SUBVOL &&
296		    key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
297			goto skip;
298
299		offset = btrfs_item_ptr_offset(leaf, slot);
300		item_size = btrfs_item_size_nr(leaf, slot);
301		if (!IS_ALIGNED(item_size, sizeof(u64))) {
302			btrfs_warn(fs_info, "uuid item with illegal size %lu!",
303				(unsigned long)item_size);
304			goto skip;
305		}
306		while (item_size) {
307			u8 uuid[BTRFS_UUID_SIZE];
308			__le64 subid_le;
309			u64 subid_cpu;
310
311			put_unaligned_le64(key.objectid, uuid);
312			put_unaligned_le64(key.offset, uuid + sizeof(u64));
313			read_extent_buffer(leaf, &subid_le, offset,
314					   sizeof(subid_le));
315			subid_cpu = le64_to_cpu(subid_le);
316			ret = check_func(fs_info, uuid, key.type, subid_cpu);
317			if (ret < 0)
318				goto out;
319			if (ret > 0) {
320				btrfs_release_path(path);
321				ret = btrfs_uuid_iter_rem(root, uuid, key.type,
322							  subid_cpu);
323				if (ret == 0) {
324					/*
325					 * this might look inefficient, but the
326					 * justification is that it is an
327					 * exception that check_func returns 1,
328					 * and that in the regular case only one
329					 * entry per UUID exists.
330					 */
331					goto again_search_slot;
332				}
333				if (ret < 0 && ret != -ENOENT)
334					goto out;
335			}
336			item_size -= sizeof(subid_le);
337			offset += sizeof(subid_le);
338		}
339
340skip:
341		ret = btrfs_next_item(root, path);
342		if (ret == 0)
343			continue;
344		else if (ret > 0)
345			ret = 0;
346		break;
347	}
348
349out:
350	btrfs_free_path(path);
351	if (ret)
352		btrfs_warn(fs_info, "btrfs_uuid_tree_iterate failed %d", ret);
353	return 0;
354}
355