| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2007 Oracle. All rights reserved. |
| */ |
| |
| #include <linux/err.h> |
| #include <linux/uuid.h> |
| #include "ctree.h" |
| #include "transaction.h" |
| #include "disk-io.h" |
| #include "print-tree.h" |
| #include "qgroup.h" |
| #include "space-info.h" |
| |
| /* |
| * Read a root item from the tree. In case we detect a root item smaller then |
| * sizeof(root_item), we know it's an old version of the root structure and |
| * initialize all new fields to zero. The same happens if we detect mismatching |
| * generation numbers as then we know the root was once mounted with an older |
| * kernel that was not aware of the root item structure change. |
| */ |
| static void btrfs_read_root_item(struct extent_buffer *eb, int slot, |
| struct btrfs_root_item *item) |
| { |
| u32 len; |
| int need_reset = 0; |
| |
| len = btrfs_item_size_nr(eb, slot); |
| read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot), |
| min_t(u32, len, sizeof(*item))); |
| if (len < sizeof(*item)) |
| need_reset = 1; |
| if (!need_reset && btrfs_root_generation(item) |
| != btrfs_root_generation_v2(item)) { |
| if (btrfs_root_generation_v2(item) != 0) { |
| btrfs_warn(eb->fs_info, |
| "mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields."); |
| } |
| need_reset = 1; |
| } |
| if (need_reset) { |
| memset(&item->generation_v2, 0, |
| sizeof(*item) - offsetof(struct btrfs_root_item, |
| generation_v2)); |
| |
| generate_random_guid(item->uuid); |
| } |
| } |
| |
| /* |
| * btrfs_find_root - lookup the root by the key. |
| * root: the root of the root tree |
| * search_key: the key to search |
| * path: the path we search |
| * root_item: the root item of the tree we look for |
| * root_key: the root key of the tree we look for |
| * |
| * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset |
| * of the search key, just lookup the root with the highest offset for a |
| * given objectid. |
| * |
| * If we find something return 0, otherwise > 0, < 0 on error. |
| */ |
| int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key, |
| struct btrfs_path *path, struct btrfs_root_item *root_item, |
| struct btrfs_key *root_key) |
| { |
| struct btrfs_key found_key; |
| struct extent_buffer *l; |
| int ret; |
| int slot; |
| |
| ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0); |
| if (ret < 0) |
| return ret; |
| |
| if (search_key->offset != -1ULL) { /* the search key is exact */ |
| if (ret > 0) |
| goto out; |
| } else { |
| BUG_ON(ret == 0); /* Logical error */ |
| if (path->slots[0] == 0) |
| goto out; |
| path->slots[0]--; |
| ret = 0; |
| } |
| |
| l = path->nodes[0]; |
| slot = path->slots[0]; |
| |
| btrfs_item_key_to_cpu(l, &found_key, slot); |
| if (found_key.objectid != search_key->objectid || |
| found_key.type != BTRFS_ROOT_ITEM_KEY) { |
| ret = 1; |
| goto out; |
| } |
| |
| if (root_item) |
| btrfs_read_root_item(l, slot, root_item); |
| if (root_key) |
| memcpy(root_key, &found_key, sizeof(found_key)); |
| out: |
| btrfs_release_path(path); |
| return ret; |
| } |
| |
| void btrfs_set_root_node(struct btrfs_root_item *item, |
| struct extent_buffer *node) |
| { |
| btrfs_set_root_bytenr(item, node->start); |
| btrfs_set_root_level(item, btrfs_header_level(node)); |
| btrfs_set_root_generation(item, btrfs_header_generation(node)); |
| } |
| |
| /* |
| * copy the data in 'item' into the btree |
| */ |
| int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_key *key, struct btrfs_root_item |
| *item) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct btrfs_path *path; |
| struct extent_buffer *l; |
| int ret; |
| int slot; |
| unsigned long ptr; |
| u32 old_len; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| |
| ret = btrfs_search_slot(trans, root, key, path, 0, 1); |
| if (ret < 0) |
| goto out; |
| |
| if (ret > 0) { |
| btrfs_crit(fs_info, |
| "unable to find root key (%llu %u %llu) in tree %llu", |
| key->objectid, key->type, key->offset, |
| root->root_key.objectid); |
| ret = -EUCLEAN; |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| |
| l = path->nodes[0]; |
| slot = path->slots[0]; |
| ptr = btrfs_item_ptr_offset(l, slot); |
| old_len = btrfs_item_size_nr(l, slot); |
| |
| /* |
| * If this is the first time we update the root item which originated |
| * from an older kernel, we need to enlarge the item size to make room |
| * for the added fields. |
| */ |
| if (old_len < sizeof(*item)) { |
| btrfs_release_path(path); |
| ret = btrfs_search_slot(trans, root, key, path, |
| -1, 1); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| |
| ret = btrfs_del_item(trans, root, path); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| btrfs_release_path(path); |
| ret = btrfs_insert_empty_item(trans, root, path, |
| key, sizeof(*item)); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| l = path->nodes[0]; |
| slot = path->slots[0]; |
| ptr = btrfs_item_ptr_offset(l, slot); |
| } |
| |
| /* |
| * Update generation_v2 so at the next mount we know the new root |
| * fields are valid. |
| */ |
| btrfs_set_root_generation_v2(item, btrfs_root_generation(item)); |
| |
| write_extent_buffer(l, item, ptr, sizeof(*item)); |
| btrfs_mark_buffer_dirty(path->nodes[0]); |
| out: |
| btrfs_free_path(path); |
| return ret; |
| } |
| |
| int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| const struct btrfs_key *key, struct btrfs_root_item *item) |
| { |
| /* |
| * Make sure generation v1 and v2 match. See update_root for details. |
| */ |
| btrfs_set_root_generation_v2(item, btrfs_root_generation(item)); |
| return btrfs_insert_item(trans, root, key, item, sizeof(*item)); |
| } |
| |
| int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info) |
| { |
| struct btrfs_root *tree_root = fs_info->tree_root; |
| struct extent_buffer *leaf; |
| struct btrfs_path *path; |
| struct btrfs_key key; |
| struct btrfs_key root_key; |
| struct btrfs_root *root; |
| int err = 0; |
| int ret; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| |
| key.objectid = BTRFS_ORPHAN_OBJECTID; |
| key.type = BTRFS_ORPHAN_ITEM_KEY; |
| key.offset = 0; |
| |
| root_key.type = BTRFS_ROOT_ITEM_KEY; |
| root_key.offset = (u64)-1; |
| |
| while (1) { |
| ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0); |
| if (ret < 0) { |
| err = ret; |
| break; |
| } |
| |
| leaf = path->nodes[0]; |
| if (path->slots[0] >= btrfs_header_nritems(leaf)) { |
| ret = btrfs_next_leaf(tree_root, path); |
| if (ret < 0) |
| err = ret; |
| if (ret != 0) |
| break; |
| leaf = path->nodes[0]; |
| } |
| |
| btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); |
| btrfs_release_path(path); |
| |
| if (key.objectid != BTRFS_ORPHAN_OBJECTID || |
| key.type != BTRFS_ORPHAN_ITEM_KEY) |
| break; |
| |
| root_key.objectid = key.offset; |
| key.offset++; |
| |
| /* |
| * The root might have been inserted already, as before we look |
| * for orphan roots, log replay might have happened, which |
| * triggers a transaction commit and qgroup accounting, which |
| * in turn reads and inserts fs roots while doing backref |
| * walking. |
| */ |
| root = btrfs_lookup_fs_root(fs_info, root_key.objectid); |
| if (root) { |
| WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, |
| &root->state)); |
| if (btrfs_root_refs(&root->root_item) == 0) { |
| set_bit(BTRFS_ROOT_DEAD_TREE, &root->state); |
| btrfs_add_dead_root(root); |
| } |
| continue; |
| } |
| |
| root = btrfs_read_fs_root(tree_root, &root_key); |
| err = PTR_ERR_OR_ZERO(root); |
| if (err && err != -ENOENT) { |
| break; |
| } else if (err == -ENOENT) { |
| struct btrfs_trans_handle *trans; |
| |
| btrfs_release_path(path); |
| |
| trans = btrfs_join_transaction(tree_root); |
| if (IS_ERR(trans)) { |
| err = PTR_ERR(trans); |
| btrfs_handle_fs_error(fs_info, err, |
| "Failed to start trans to delete orphan item"); |
| break; |
| } |
| err = btrfs_del_orphan_item(trans, tree_root, |
| root_key.objectid); |
| btrfs_end_transaction(trans); |
| if (err) { |
| btrfs_handle_fs_error(fs_info, err, |
| "Failed to delete root orphan item"); |
| break; |
| } |
| continue; |
| } |
| |
| err = btrfs_init_fs_root(root); |
| if (err) { |
| btrfs_free_fs_root(root); |
| break; |
| } |
| |
| set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state); |
| |
| err = btrfs_insert_fs_root(fs_info, root); |
| if (err) { |
| BUG_ON(err == -EEXIST); |
| btrfs_free_fs_root(root); |
| break; |
| } |
| |
| if (btrfs_root_refs(&root->root_item) == 0) { |
| set_bit(BTRFS_ROOT_DEAD_TREE, &root->state); |
| btrfs_add_dead_root(root); |
| } |
| } |
| |
| btrfs_free_path(path); |
| return err; |
| } |
| |
| /* drop the root item for 'key' from the tree root */ |
| int btrfs_del_root(struct btrfs_trans_handle *trans, |
| const struct btrfs_key *key) |
| { |
| struct btrfs_root *root = trans->fs_info->tree_root; |
| struct btrfs_path *path; |
| int ret; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| ret = btrfs_search_slot(trans, root, key, path, -1, 1); |
| if (ret < 0) |
| goto out; |
| |
| BUG_ON(ret != 0); |
| |
| ret = btrfs_del_item(trans, root, path); |
| out: |
| btrfs_free_path(path); |
| return ret; |
| } |
| |
| int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id, |
| u64 ref_id, u64 dirid, u64 *sequence, const char *name, |
| int name_len) |
| |
| { |
| struct btrfs_root *tree_root = trans->fs_info->tree_root; |
| struct btrfs_path *path; |
| struct btrfs_root_ref *ref; |
| struct extent_buffer *leaf; |
| struct btrfs_key key; |
| unsigned long ptr; |
| int err = 0; |
| int ret; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| |
| key.objectid = root_id; |
| key.type = BTRFS_ROOT_BACKREF_KEY; |
| key.offset = ref_id; |
| again: |
| ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); |
| if (ret < 0) { |
| err = ret; |
| goto out; |
| } else if (ret == 0) { |
| leaf = path->nodes[0]; |
| ref = btrfs_item_ptr(leaf, path->slots[0], |
| struct btrfs_root_ref); |
| ptr = (unsigned long)(ref + 1); |
| if ((btrfs_root_ref_dirid(leaf, ref) != dirid) || |
| (btrfs_root_ref_name_len(leaf, ref) != name_len) || |
| memcmp_extent_buffer(leaf, name, ptr, name_len)) { |
| err = -ENOENT; |
| goto out; |
| } |
| *sequence = btrfs_root_ref_sequence(leaf, ref); |
| |
| ret = btrfs_del_item(trans, tree_root, path); |
| if (ret) { |
| err = ret; |
| goto out; |
| } |
| } else |
| err = -ENOENT; |
| |
| if (key.type == BTRFS_ROOT_BACKREF_KEY) { |
| btrfs_release_path(path); |
| key.objectid = ref_id; |
| key.type = BTRFS_ROOT_REF_KEY; |
| key.offset = root_id; |
| goto again; |
| } |
| |
| out: |
| btrfs_free_path(path); |
| return err; |
| } |
| |
| /* |
| * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY |
| * or BTRFS_ROOT_BACKREF_KEY. |
| * |
| * The dirid, sequence, name and name_len refer to the directory entry |
| * that is referencing the root. |
| * |
| * For a forward ref, the root_id is the id of the tree referencing |
| * the root and ref_id is the id of the subvol or snapshot. |
| * |
| * For a back ref the root_id is the id of the subvol or snapshot and |
| * ref_id is the id of the tree referencing it. |
| * |
| * Will return 0, -ENOMEM, or anything from the CoW path |
| */ |
| int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id, |
| u64 ref_id, u64 dirid, u64 sequence, const char *name, |
| int name_len) |
| { |
| struct btrfs_root *tree_root = trans->fs_info->tree_root; |
| struct btrfs_key key; |
| int ret; |
| struct btrfs_path *path; |
| struct btrfs_root_ref *ref; |
| struct extent_buffer *leaf; |
| unsigned long ptr; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| |
| key.objectid = root_id; |
| key.type = BTRFS_ROOT_BACKREF_KEY; |
| key.offset = ref_id; |
| again: |
| ret = btrfs_insert_empty_item(trans, tree_root, path, &key, |
| sizeof(*ref) + name_len); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| btrfs_free_path(path); |
| return ret; |
| } |
| |
| leaf = path->nodes[0]; |
| ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); |
| btrfs_set_root_ref_dirid(leaf, ref, dirid); |
| btrfs_set_root_ref_sequence(leaf, ref, sequence); |
| btrfs_set_root_ref_name_len(leaf, ref, name_len); |
| ptr = (unsigned long)(ref + 1); |
| write_extent_buffer(leaf, name, ptr, name_len); |
| btrfs_mark_buffer_dirty(leaf); |
| |
| if (key.type == BTRFS_ROOT_BACKREF_KEY) { |
| btrfs_release_path(path); |
| key.objectid = ref_id; |
| key.type = BTRFS_ROOT_REF_KEY; |
| key.offset = root_id; |
| goto again; |
| } |
| |
| btrfs_free_path(path); |
| return 0; |
| } |
| |
| /* |
| * Old btrfs forgets to init root_item->flags and root_item->byte_limit |
| * for subvolumes. To work around this problem, we steal a bit from |
| * root_item->inode_item->flags, and use it to indicate if those fields |
| * have been properly initialized. |
| */ |
| void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item) |
| { |
| u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode); |
| |
| if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) { |
| inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT; |
| btrfs_set_stack_inode_flags(&root_item->inode, inode_flags); |
| btrfs_set_root_flags(root_item, 0); |
| btrfs_set_root_limit(root_item, 0); |
| } |
| } |
| |
| void btrfs_update_root_times(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| struct btrfs_root_item *item = &root->root_item; |
| struct timespec64 ct; |
| |
| ktime_get_real_ts64(&ct); |
| spin_lock(&root->root_item_lock); |
| btrfs_set_root_ctransid(item, trans->transid); |
| btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec); |
| btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec); |
| spin_unlock(&root->root_item_lock); |
| } |
| |
| /* |
| * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation |
| * root: the root of the parent directory |
| * rsv: block reservation |
| * items: the number of items that we need do reservation |
| * use_global_rsv: allow fallback to the global block reservation |
| * |
| * This function is used to reserve the space for snapshot/subvolume |
| * creation and deletion. Those operations are different with the |
| * common file/directory operations, they change two fs/file trees |
| * and root tree, the number of items that the qgroup reserves is |
| * different with the free space reservation. So we can not use |
| * the space reservation mechanism in start_transaction(). |
| */ |
| int btrfs_subvolume_reserve_metadata(struct btrfs_root *root, |
| struct btrfs_block_rsv *rsv, int items, |
| bool use_global_rsv) |
| { |
| u64 qgroup_num_bytes = 0; |
| u64 num_bytes; |
| int ret; |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; |
| |
| if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) { |
| /* One for parent inode, two for dir entries */ |
| qgroup_num_bytes = 3 * fs_info->nodesize; |
| ret = btrfs_qgroup_reserve_meta_prealloc(root, |
| qgroup_num_bytes, true); |
| if (ret) |
| return ret; |
| } |
| |
| num_bytes = btrfs_calc_insert_metadata_size(fs_info, items); |
| rsv->space_info = btrfs_find_space_info(fs_info, |
| BTRFS_BLOCK_GROUP_METADATA); |
| ret = btrfs_block_rsv_add(root, rsv, num_bytes, |
| BTRFS_RESERVE_FLUSH_ALL); |
| |
| if (ret == -ENOSPC && use_global_rsv) |
| ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true); |
| |
| if (ret && qgroup_num_bytes) |
| btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes); |
| |
| return ret; |
| } |
| |
| void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info, |
| struct btrfs_block_rsv *rsv) |
| { |
| btrfs_block_rsv_release(fs_info, rsv, (u64)-1); |
| } |