1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) STRATO AG 2013. All rights reserved.
6 #include <linux/uuid.h>
7 #include <asm/unaligned.h>
9 #include "transaction.h"
11 #include "print-tree.h"
14 static void btrfs_uuid_to_key(u8 *uuid, u8 type, struct btrfs_key *key)
17 key->objectid = get_unaligned_le64(uuid);
18 key->offset = get_unaligned_le64(uuid + sizeof(u64));
21 /* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
22 static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
26 struct btrfs_path *path = NULL;
27 struct extent_buffer *eb;
33 if (WARN_ON_ONCE(!uuid_root)) {
38 path = btrfs_alloc_path();
44 btrfs_uuid_to_key(uuid, type, &key);
45 ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
54 slot = path->slots[0];
55 item_size = btrfs_item_size_nr(eb, slot);
56 offset = btrfs_item_ptr_offset(eb, slot);
59 if (!IS_ALIGNED(item_size, sizeof(u64))) {
60 btrfs_warn(uuid_root->fs_info,
61 "uuid item with illegal size %lu!",
62 (unsigned long)item_size);
68 read_extent_buffer(eb, &data, offset, sizeof(data));
69 if (le64_to_cpu(data) == subid) {
73 offset += sizeof(data);
74 item_size -= sizeof(data);
78 btrfs_free_path(path);
82 int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
85 struct btrfs_fs_info *fs_info = trans->fs_info;
86 struct btrfs_root *uuid_root = fs_info->uuid_root;
88 struct btrfs_path *path = NULL;
90 struct extent_buffer *eb;
95 ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
99 if (WARN_ON_ONCE(!uuid_root)) {
104 btrfs_uuid_to_key(uuid, type, &key);
106 path = btrfs_alloc_path();
112 ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
115 /* Add an item for the type for the first time */
117 slot = path->slots[0];
118 offset = btrfs_item_ptr_offset(eb, slot);
119 } else if (ret == -EEXIST) {
121 * An item with that type already exists.
122 * Extend the item and store the new subid at the end.
124 btrfs_extend_item(path, sizeof(subid_le));
126 slot = path->slots[0];
127 offset = btrfs_item_ptr_offset(eb, slot);
128 offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le);
131 "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
132 ret, (unsigned long long)key.objectid,
133 (unsigned long long)key.offset, type);
138 subid_le = cpu_to_le64(subid_cpu);
139 write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
140 btrfs_mark_buffer_dirty(eb);
143 btrfs_free_path(path);
147 int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
150 struct btrfs_fs_info *fs_info = trans->fs_info;
151 struct btrfs_root *uuid_root = fs_info->uuid_root;
153 struct btrfs_path *path = NULL;
154 struct btrfs_key key;
155 struct extent_buffer *eb;
157 unsigned long offset;
159 unsigned long move_dst;
160 unsigned long move_src;
161 unsigned long move_len;
163 if (WARN_ON_ONCE(!uuid_root)) {
168 btrfs_uuid_to_key(uuid, type, &key);
170 path = btrfs_alloc_path();
176 ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
178 btrfs_warn(fs_info, "error %d while searching for uuid item!",
188 slot = path->slots[0];
189 offset = btrfs_item_ptr_offset(eb, slot);
190 item_size = btrfs_item_size_nr(eb, slot);
191 if (!IS_ALIGNED(item_size, sizeof(u64))) {
192 btrfs_warn(fs_info, "uuid item with illegal size %lu!",
193 (unsigned long)item_size);
200 read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
201 if (le64_to_cpu(read_subid) == subid)
203 offset += sizeof(read_subid);
204 item_size -= sizeof(read_subid);
212 item_size = btrfs_item_size_nr(eb, slot);
213 if (item_size == sizeof(subid)) {
214 ret = btrfs_del_item(trans, uuid_root, path);
219 move_src = offset + sizeof(subid);
220 move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
221 memmove_extent_buffer(eb, move_dst, move_src, move_len);
222 btrfs_truncate_item(path, item_size - sizeof(subid), 1);
225 btrfs_free_path(path);
229 static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
232 struct btrfs_trans_handle *trans;
235 /* 1 - for the uuid item */
236 trans = btrfs_start_transaction(uuid_root, 1);
238 ret = PTR_ERR(trans);
242 ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
243 btrfs_end_transaction(trans);
250 * Check if there's an matching subvolume for given UUID
253 * 0 check succeeded, the entry is not outdated
254 * > 0 if the check failed, the caller should remove the entry
255 * < 0 if an error occurred
257 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
258 u8 *uuid, u8 type, u64 subvolid)
261 struct btrfs_root *subvol_root;
263 if (type != BTRFS_UUID_KEY_SUBVOL &&
264 type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
267 subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
268 if (IS_ERR(subvol_root)) {
269 ret = PTR_ERR(subvol_root);
276 case BTRFS_UUID_KEY_SUBVOL:
277 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
280 case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
281 if (memcmp(uuid, subvol_root->root_item.received_uuid,
286 btrfs_put_root(subvol_root);
291 int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
293 struct btrfs_root *root = fs_info->uuid_root;
294 struct btrfs_key key;
295 struct btrfs_path *path;
297 struct extent_buffer *leaf;
300 unsigned long offset;
302 path = btrfs_alloc_path();
313 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
321 if (btrfs_fs_closing(fs_info)) {
326 leaf = path->nodes[0];
327 slot = path->slots[0];
328 btrfs_item_key_to_cpu(leaf, &key, slot);
330 if (key.type != BTRFS_UUID_KEY_SUBVOL &&
331 key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
334 offset = btrfs_item_ptr_offset(leaf, slot);
335 item_size = btrfs_item_size_nr(leaf, slot);
336 if (!IS_ALIGNED(item_size, sizeof(u64))) {
338 "uuid item with illegal size %lu!",
339 (unsigned long)item_size);
343 u8 uuid[BTRFS_UUID_SIZE];
347 put_unaligned_le64(key.objectid, uuid);
348 put_unaligned_le64(key.offset, uuid + sizeof(u64));
349 read_extent_buffer(leaf, &subid_le, offset,
351 subid_cpu = le64_to_cpu(subid_le);
352 ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
353 key.type, subid_cpu);
357 btrfs_release_path(path);
358 ret = btrfs_uuid_iter_rem(root, uuid, key.type,
362 * this might look inefficient, but the
363 * justification is that it is an
364 * exception that check_func returns 1,
365 * and that in the regular case only one
366 * entry per UUID exists.
368 goto again_search_slot;
370 if (ret < 0 && ret != -ENOENT)
373 goto again_search_slot;
375 item_size -= sizeof(subid_le);
376 offset += sizeof(subid_le);
380 ret = btrfs_next_item(root, path);
389 btrfs_free_path(path);