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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2007 Oracle. All rights reserved.4 */5 6#include <linux/err.h>7#include <linux/uuid.h>8#include "ctree.h"9#include "fs.h"10#include "messages.h"11#include "transaction.h"12#include "disk-io.h"13#include "qgroup.h"14#include "space-info.h"15#include "accessors.h"16#include "root-tree.h"17#include "orphan.h"18 19/*20 * Read a root item from the tree. In case we detect a root item smaller then21 * sizeof(root_item), we know it's an old version of the root structure and22 * initialize all new fields to zero. The same happens if we detect mismatching23 * generation numbers as then we know the root was once mounted with an older24 * kernel that was not aware of the root item structure change.25 */26static void btrfs_read_root_item(struct extent_buffer *eb, int slot,27 struct btrfs_root_item *item)28{29 u32 len;30 int need_reset = 0;31 32 len = btrfs_item_size(eb, slot);33 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),34 min_t(u32, len, sizeof(*item)));35 if (len < sizeof(*item))36 need_reset = 1;37 if (!need_reset && btrfs_root_generation(item)38 != btrfs_root_generation_v2(item)) {39 if (btrfs_root_generation_v2(item) != 0) {40 btrfs_warn(eb->fs_info,41 "mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");42 }43 need_reset = 1;44 }45 if (need_reset) {46 /* Clear all members from generation_v2 onwards. */47 memset_startat(item, 0, generation_v2);48 generate_random_guid(item->uuid);49 }50}51 52/*53 * Lookup the root by the key.54 *55 * root: the root of the root tree56 * search_key: the key to search57 * path: the path we search58 * root_item: the root item of the tree we look for59 * root_key: the root key of the tree we look for60 *61 * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset62 * of the search key, just lookup the root with the highest offset for a63 * given objectid.64 *65 * If we find something return 0, otherwise > 0, < 0 on error.66 */67int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,68 struct btrfs_path *path, struct btrfs_root_item *root_item,69 struct btrfs_key *root_key)70{71 struct btrfs_key found_key;72 struct extent_buffer *l;73 int ret;74 int slot;75 76 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);77 if (ret < 0)78 return ret;79 80 if (search_key->offset != -1ULL) { /* the search key is exact */81 if (ret > 0)82 goto out;83 } else {84 /*85 * Key with offset -1 found, there would have to exist a root86 * with such id, but this is out of the valid range.87 */88 if (ret == 0) {89 ret = -EUCLEAN;90 goto out;91 }92 if (path->slots[0] == 0)93 goto out;94 path->slots[0]--;95 ret = 0;96 }97 98 l = path->nodes[0];99 slot = path->slots[0];100 101 btrfs_item_key_to_cpu(l, &found_key, slot);102 if (found_key.objectid != search_key->objectid ||103 found_key.type != BTRFS_ROOT_ITEM_KEY) {104 ret = 1;105 goto out;106 }107 108 if (root_item)109 btrfs_read_root_item(l, slot, root_item);110 if (root_key)111 memcpy(root_key, &found_key, sizeof(found_key));112out:113 btrfs_release_path(path);114 return ret;115}116 117void btrfs_set_root_node(struct btrfs_root_item *item,118 struct extent_buffer *node)119{120 btrfs_set_root_bytenr(item, node->start);121 btrfs_set_root_level(item, btrfs_header_level(node));122 btrfs_set_root_generation(item, btrfs_header_generation(node));123}124 125/*126 * copy the data in 'item' into the btree127 */128int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root129 *root, struct btrfs_key *key, struct btrfs_root_item130 *item)131{132 struct btrfs_fs_info *fs_info = root->fs_info;133 struct btrfs_path *path;134 struct extent_buffer *l;135 int ret;136 int slot;137 unsigned long ptr;138 u32 old_len;139 140 path = btrfs_alloc_path();141 if (!path)142 return -ENOMEM;143 144 ret = btrfs_search_slot(trans, root, key, path, 0, 1);145 if (ret < 0)146 goto out;147 148 if (ret > 0) {149 btrfs_crit(fs_info,150 "unable to find root key (%llu %u %llu) in tree %llu",151 key->objectid, key->type, key->offset, btrfs_root_id(root));152 ret = -EUCLEAN;153 btrfs_abort_transaction(trans, ret);154 goto out;155 }156 157 l = path->nodes[0];158 slot = path->slots[0];159 ptr = btrfs_item_ptr_offset(l, slot);160 old_len = btrfs_item_size(l, slot);161 162 /*163 * If this is the first time we update the root item which originated164 * from an older kernel, we need to enlarge the item size to make room165 * for the added fields.166 */167 if (old_len < sizeof(*item)) {168 btrfs_release_path(path);169 ret = btrfs_search_slot(trans, root, key, path,170 -1, 1);171 if (ret < 0) {172 btrfs_abort_transaction(trans, ret);173 goto out;174 }175 176 ret = btrfs_del_item(trans, root, path);177 if (ret < 0) {178 btrfs_abort_transaction(trans, ret);179 goto out;180 }181 btrfs_release_path(path);182 ret = btrfs_insert_empty_item(trans, root, path,183 key, sizeof(*item));184 if (ret < 0) {185 btrfs_abort_transaction(trans, ret);186 goto out;187 }188 l = path->nodes[0];189 slot = path->slots[0];190 ptr = btrfs_item_ptr_offset(l, slot);191 }192 193 /*194 * Update generation_v2 so at the next mount we know the new root195 * fields are valid.196 */197 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));198 199 write_extent_buffer(l, item, ptr, sizeof(*item));200 btrfs_mark_buffer_dirty(trans, path->nodes[0]);201out:202 btrfs_free_path(path);203 return ret;204}205 206int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,207 const struct btrfs_key *key, struct btrfs_root_item *item)208{209 /*210 * Make sure generation v1 and v2 match. See update_root for details.211 */212 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));213 return btrfs_insert_item(trans, root, key, item, sizeof(*item));214}215 216int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)217{218 struct btrfs_root *tree_root = fs_info->tree_root;219 struct extent_buffer *leaf;220 struct btrfs_path *path;221 struct btrfs_key key;222 struct btrfs_root *root;223 int err = 0;224 int ret;225 226 path = btrfs_alloc_path();227 if (!path)228 return -ENOMEM;229 230 key.objectid = BTRFS_ORPHAN_OBJECTID;231 key.type = BTRFS_ORPHAN_ITEM_KEY;232 key.offset = 0;233 234 while (1) {235 u64 root_objectid;236 237 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);238 if (ret < 0) {239 err = ret;240 break;241 }242 243 leaf = path->nodes[0];244 if (path->slots[0] >= btrfs_header_nritems(leaf)) {245 ret = btrfs_next_leaf(tree_root, path);246 if (ret < 0)247 err = ret;248 if (ret != 0)249 break;250 leaf = path->nodes[0];251 }252 253 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);254 btrfs_release_path(path);255 256 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||257 key.type != BTRFS_ORPHAN_ITEM_KEY)258 break;259 260 root_objectid = key.offset;261 key.offset++;262 263 root = btrfs_get_fs_root(fs_info, root_objectid, false);264 err = PTR_ERR_OR_ZERO(root);265 if (err && err != -ENOENT) {266 break;267 } else if (err == -ENOENT) {268 struct btrfs_trans_handle *trans;269 270 btrfs_release_path(path);271 272 trans = btrfs_join_transaction(tree_root);273 if (IS_ERR(trans)) {274 err = PTR_ERR(trans);275 btrfs_handle_fs_error(fs_info, err,276 "Failed to start trans to delete orphan item");277 break;278 }279 err = btrfs_del_orphan_item(trans, tree_root,280 root_objectid);281 btrfs_end_transaction(trans);282 if (err) {283 btrfs_handle_fs_error(fs_info, err,284 "Failed to delete root orphan item");285 break;286 }287 continue;288 }289 290 WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state));291 if (btrfs_root_refs(&root->root_item) == 0) {292 struct btrfs_key drop_key;293 294 btrfs_disk_key_to_cpu(&drop_key, &root->root_item.drop_progress);295 /*296 * If we have a non-zero drop_progress then we know we297 * made it partly through deleting this snapshot, and298 * thus we need to make sure we block any balance from299 * happening until this snapshot is completely dropped.300 */301 if (drop_key.objectid != 0 || drop_key.type != 0 ||302 drop_key.offset != 0) {303 set_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);304 set_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);305 }306 307 set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);308 btrfs_add_dead_root(root);309 }310 btrfs_put_root(root);311 }312 313 btrfs_free_path(path);314 return err;315}316 317/* drop the root item for 'key' from the tree root */318int btrfs_del_root(struct btrfs_trans_handle *trans,319 const struct btrfs_key *key)320{321 struct btrfs_root *root = trans->fs_info->tree_root;322 struct btrfs_path *path;323 int ret;324 325 path = btrfs_alloc_path();326 if (!path)327 return -ENOMEM;328 ret = btrfs_search_slot(trans, root, key, path, -1, 1);329 if (ret < 0)330 goto out;331 if (ret != 0) {332 /* The root must exist but we did not find it by the key. */333 ret = -EUCLEAN;334 goto out;335 }336 337 ret = btrfs_del_item(trans, root, path);338out:339 btrfs_free_path(path);340 return ret;341}342 343int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,344 u64 ref_id, u64 dirid, u64 *sequence,345 const struct fscrypt_str *name)346{347 struct btrfs_root *tree_root = trans->fs_info->tree_root;348 struct btrfs_path *path;349 struct btrfs_root_ref *ref;350 struct extent_buffer *leaf;351 struct btrfs_key key;352 unsigned long ptr;353 int ret;354 355 path = btrfs_alloc_path();356 if (!path)357 return -ENOMEM;358 359 key.objectid = root_id;360 key.type = BTRFS_ROOT_BACKREF_KEY;361 key.offset = ref_id;362again:363 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);364 if (ret < 0) {365 goto out;366 } else if (ret == 0) {367 leaf = path->nodes[0];368 ref = btrfs_item_ptr(leaf, path->slots[0],369 struct btrfs_root_ref);370 ptr = (unsigned long)(ref + 1);371 if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||372 (btrfs_root_ref_name_len(leaf, ref) != name->len) ||373 memcmp_extent_buffer(leaf, name->name, ptr, name->len)) {374 ret = -ENOENT;375 goto out;376 }377 *sequence = btrfs_root_ref_sequence(leaf, ref);378 379 ret = btrfs_del_item(trans, tree_root, path);380 if (ret)381 goto out;382 } else {383 ret = -ENOENT;384 goto out;385 }386 387 if (key.type == BTRFS_ROOT_BACKREF_KEY) {388 btrfs_release_path(path);389 key.objectid = ref_id;390 key.type = BTRFS_ROOT_REF_KEY;391 key.offset = root_id;392 goto again;393 }394 395out:396 btrfs_free_path(path);397 return ret;398}399 400/*401 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY402 * or BTRFS_ROOT_BACKREF_KEY.403 *404 * The dirid, sequence, name and name_len refer to the directory entry405 * that is referencing the root.406 *407 * For a forward ref, the root_id is the id of the tree referencing408 * the root and ref_id is the id of the subvol or snapshot.409 *410 * For a back ref the root_id is the id of the subvol or snapshot and411 * ref_id is the id of the tree referencing it.412 *413 * Will return 0, -ENOMEM, or anything from the CoW path414 */415int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,416 u64 ref_id, u64 dirid, u64 sequence,417 const struct fscrypt_str *name)418{419 struct btrfs_root *tree_root = trans->fs_info->tree_root;420 struct btrfs_key key;421 int ret;422 struct btrfs_path *path;423 struct btrfs_root_ref *ref;424 struct extent_buffer *leaf;425 unsigned long ptr;426 427 path = btrfs_alloc_path();428 if (!path)429 return -ENOMEM;430 431 key.objectid = root_id;432 key.type = BTRFS_ROOT_BACKREF_KEY;433 key.offset = ref_id;434again:435 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,436 sizeof(*ref) + name->len);437 if (ret) {438 btrfs_abort_transaction(trans, ret);439 btrfs_free_path(path);440 return ret;441 }442 443 leaf = path->nodes[0];444 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);445 btrfs_set_root_ref_dirid(leaf, ref, dirid);446 btrfs_set_root_ref_sequence(leaf, ref, sequence);447 btrfs_set_root_ref_name_len(leaf, ref, name->len);448 ptr = (unsigned long)(ref + 1);449 write_extent_buffer(leaf, name->name, ptr, name->len);450 btrfs_mark_buffer_dirty(trans, leaf);451 452 if (key.type == BTRFS_ROOT_BACKREF_KEY) {453 btrfs_release_path(path);454 key.objectid = ref_id;455 key.type = BTRFS_ROOT_REF_KEY;456 key.offset = root_id;457 goto again;458 }459 460 btrfs_free_path(path);461 return 0;462}463 464/*465 * Old btrfs forgets to init root_item->flags and root_item->byte_limit466 * for subvolumes. To work around this problem, we steal a bit from467 * root_item->inode_item->flags, and use it to indicate if those fields468 * have been properly initialized.469 */470void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)471{472 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);473 474 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {475 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;476 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);477 btrfs_set_root_flags(root_item, 0);478 btrfs_set_root_limit(root_item, 0);479 }480}481 482void btrfs_update_root_times(struct btrfs_trans_handle *trans,483 struct btrfs_root *root)484{485 struct btrfs_root_item *item = &root->root_item;486 struct timespec64 ct;487 488 ktime_get_real_ts64(&ct);489 spin_lock(&root->root_item_lock);490 btrfs_set_root_ctransid(item, trans->transid);491 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);492 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);493 spin_unlock(&root->root_item_lock);494}495 496/*497 * Reserve space for subvolume operation.498 *499 * root: the root of the parent directory500 * rsv: block reservation501 * items: the number of items that we need do reservation502 * use_global_rsv: allow fallback to the global block reservation503 *504 * This function is used to reserve the space for snapshot/subvolume505 * creation and deletion. Those operations are different with the506 * common file/directory operations, they change two fs/file trees507 * and root tree, the number of items that the qgroup reserves is508 * different with the free space reservation. So we can not use509 * the space reservation mechanism in start_transaction().510 */511int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,512 struct btrfs_block_rsv *rsv, int items,513 bool use_global_rsv)514{515 u64 qgroup_num_bytes = 0;516 u64 num_bytes;517 int ret;518 struct btrfs_fs_info *fs_info = root->fs_info;519 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;520 521 if (btrfs_qgroup_enabled(fs_info)) {522 /* One for parent inode, two for dir entries */523 qgroup_num_bytes = 3 * fs_info->nodesize;524 ret = btrfs_qgroup_reserve_meta_prealloc(root,525 qgroup_num_bytes, true,526 false);527 if (ret)528 return ret;529 }530 531 num_bytes = btrfs_calc_insert_metadata_size(fs_info, items);532 rsv->space_info = btrfs_find_space_info(fs_info,533 BTRFS_BLOCK_GROUP_METADATA);534 ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes,535 BTRFS_RESERVE_FLUSH_ALL);536 537 if (ret == -ENOSPC && use_global_rsv)538 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);539 540 if (ret && qgroup_num_bytes)541 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);542 543 if (!ret) {544 spin_lock(&rsv->lock);545 rsv->qgroup_rsv_reserved += qgroup_num_bytes;546 spin_unlock(&rsv->lock);547 }548 return ret;549}550