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,
 73			   "uuid item with illegal size %lu!",
 74			   (unsigned long)item_size);
 75		goto out;
 76	}
 77	while (item_size) {
 78		__le64 data;
 79
 80		read_extent_buffer(eb, &data, offset, sizeof(data));
 81		if (le64_to_cpu(data) == subid) {
 82			ret = 0;
 83			break;
 84		}
 85		offset += sizeof(data);
 86		item_size -= sizeof(data);
 87	}
 88
 89out:
 90	btrfs_free_path(path);
 91	return ret;
 92}
 93
 94int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans,
 95			struct btrfs_fs_info *fs_info, u8 *uuid, u8 type,
 96			u64 subid_cpu)
 97{
 98	struct btrfs_root *uuid_root = fs_info->uuid_root;
 99	int ret;
100	struct btrfs_path *path = NULL;
101	struct btrfs_key key;
102	struct extent_buffer *eb;
103	int slot;
104	unsigned long offset;
105	__le64 subid_le;
106
107	ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
108	if (ret != -ENOENT)
109		return ret;
110
111	if (WARN_ON_ONCE(!uuid_root)) {
112		ret = -EINVAL;
113		goto out;
114	}
115
116	btrfs_uuid_to_key(uuid, type, &key);
117
118	path = btrfs_alloc_path();
119	if (!path) {
120		ret = -ENOMEM;
121		goto out;
122	}
123
124	ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
125				      sizeof(subid_le));
126	if (ret >= 0) {
127		/* Add an item for the type for the first time */
128		eb = path->nodes[0];
129		slot = path->slots[0];
130		offset = btrfs_item_ptr_offset(eb, slot);
131	} else if (ret == -EEXIST) {
132		/*
133		 * An item with that type already exists.
134		 * Extend the item and store the new subid at the end.
135		 */
136		btrfs_extend_item(fs_info, path, sizeof(subid_le));
137		eb = path->nodes[0];
138		slot = path->slots[0];
139		offset = btrfs_item_ptr_offset(eb, slot);
140		offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le);
141	} else if (ret < 0) {
142		btrfs_warn(fs_info,
143			   "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
144			   ret, (unsigned long long)key.objectid,
145			   (unsigned long long)key.offset, type);
146		goto out;
147	}
148
149	ret = 0;
150	subid_le = cpu_to_le64(subid_cpu);
151	write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
152	btrfs_mark_buffer_dirty(eb);
153
154out:
155	btrfs_free_path(path);
156	return ret;
157}
158
159int btrfs_uuid_tree_rem(struct btrfs_trans_handle *trans,
160			struct btrfs_fs_info *fs_info, u8 *uuid, u8 type,
161			u64 subid)
162{
163	struct btrfs_root *uuid_root = fs_info->uuid_root;
164	int ret;
165	struct btrfs_path *path = NULL;
166	struct btrfs_key key;
167	struct extent_buffer *eb;
168	int slot;
169	unsigned long offset;
170	u32 item_size;
171	unsigned long move_dst;
172	unsigned long move_src;
173	unsigned long move_len;
174
175	if (WARN_ON_ONCE(!uuid_root)) {
176		ret = -EINVAL;
177		goto out;
178	}
179
180	btrfs_uuid_to_key(uuid, type, &key);
181
182	path = btrfs_alloc_path();
183	if (!path) {
184		ret = -ENOMEM;
185		goto out;
186	}
187
188	ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
189	if (ret < 0) {
190		btrfs_warn(fs_info, "error %d while searching for uuid item!",
191			   ret);
192		goto out;
193	}
194	if (ret > 0) {
195		ret = -ENOENT;
196		goto out;
197	}
198
199	eb = path->nodes[0];
200	slot = path->slots[0];
201	offset = btrfs_item_ptr_offset(eb, slot);
202	item_size = btrfs_item_size_nr(eb, slot);
203	if (!IS_ALIGNED(item_size, sizeof(u64))) {
204		btrfs_warn(fs_info, "uuid item with illegal size %lu!",
205			   (unsigned long)item_size);
206		ret = -ENOENT;
207		goto out;
208	}
209	while (item_size) {
210		__le64 read_subid;
211
212		read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
213		if (le64_to_cpu(read_subid) == subid)
214			break;
215		offset += sizeof(read_subid);
216		item_size -= sizeof(read_subid);
217	}
218
219	if (!item_size) {
220		ret = -ENOENT;
221		goto out;
222	}
223
224	item_size = btrfs_item_size_nr(eb, slot);
225	if (item_size == sizeof(subid)) {
226		ret = btrfs_del_item(trans, uuid_root, path);
227		goto out;
228	}
229
230	move_dst = offset;
231	move_src = offset + sizeof(subid);
232	move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
233	memmove_extent_buffer(eb, move_dst, move_src, move_len);
234	btrfs_truncate_item(fs_info, path, item_size - sizeof(subid), 1);
235
236out:
237	btrfs_free_path(path);
238	return ret;
239}
240
241static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
242			       u64 subid)
243{
244	struct btrfs_trans_handle *trans;
245	int ret;
246
247	/* 1 - for the uuid item */
248	trans = btrfs_start_transaction(uuid_root, 1);
249	if (IS_ERR(trans)) {
250		ret = PTR_ERR(trans);
251		goto out;
252	}
253
254	ret = btrfs_uuid_tree_rem(trans, uuid_root->fs_info, uuid, type, subid);
255	btrfs_end_transaction(trans);
256
257out:
258	return ret;
259}
260
261int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info,
262			    int (*check_func)(struct btrfs_fs_info *, u8 *, u8,
263					      u64))
264{
265	struct btrfs_root *root = fs_info->uuid_root;
266	struct btrfs_key key;
267	struct btrfs_path *path;
268	int ret = 0;
269	struct extent_buffer *leaf;
270	int slot;
271	u32 item_size;
272	unsigned long offset;
273
274	path = btrfs_alloc_path();
275	if (!path) {
276		ret = -ENOMEM;
277		goto out;
278	}
279
280	key.objectid = 0;
281	key.type = 0;
282	key.offset = 0;
283
284again_search_slot:
285	ret = btrfs_search_forward(root, &key, path, 0);
286	if (ret) {
287		if (ret > 0)
288			ret = 0;
289		goto out;
290	}
291
292	while (1) {
293		cond_resched();
294		leaf = path->nodes[0];
295		slot = path->slots[0];
296		btrfs_item_key_to_cpu(leaf, &key, slot);
297
298		if (key.type != BTRFS_UUID_KEY_SUBVOL &&
299		    key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
300			goto skip;
301
302		offset = btrfs_item_ptr_offset(leaf, slot);
303		item_size = btrfs_item_size_nr(leaf, slot);
304		if (!IS_ALIGNED(item_size, sizeof(u64))) {
305			btrfs_warn(fs_info,
306				   "uuid item with illegal size %lu!",
307				   (unsigned long)item_size);
308			goto skip;
309		}
310		while (item_size) {
311			u8 uuid[BTRFS_UUID_SIZE];
312			__le64 subid_le;
313			u64 subid_cpu;
314
315			put_unaligned_le64(key.objectid, uuid);
316			put_unaligned_le64(key.offset, uuid + sizeof(u64));
317			read_extent_buffer(leaf, &subid_le, offset,
318					   sizeof(subid_le));
319			subid_cpu = le64_to_cpu(subid_le);
320			ret = check_func(fs_info, uuid, key.type, subid_cpu);
321			if (ret < 0)
322				goto out;
323			if (ret > 0) {
324				btrfs_release_path(path);
325				ret = btrfs_uuid_iter_rem(root, uuid, key.type,
326							  subid_cpu);
327				if (ret == 0) {
328					/*
329					 * this might look inefficient, but the
330					 * justification is that it is an
331					 * exception that check_func returns 1,
332					 * and that in the regular case only one
333					 * entry per UUID exists.
334					 */
335					goto again_search_slot;
336				}
337				if (ret < 0 && ret != -ENOENT)
338					goto out;
339			}
340			item_size -= sizeof(subid_le);
341			offset += sizeof(subid_le);
342		}
343
344skip:
345		ret = btrfs_next_item(root, path);
346		if (ret == 0)
347			continue;
348		else if (ret > 0)
349			ret = 0;
350		break;
351	}
352
353out:
354	btrfs_free_path(path);
355	return ret;
356}