From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- fs/btrfs/root-tree.c | 497 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 497 insertions(+) create mode 100644 fs/btrfs/root-tree.c (limited to 'fs/btrfs/root-tree.c') diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c new file mode 100644 index 000000000..360a728a6 --- /dev/null +++ b/fs/btrfs/root-tree.c @@ -0,0 +1,497 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include +#include +#include "ctree.h" +#include "transaction.h" +#include "disk-io.h" +#include "print-tree.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) +{ + uuid_le uuid; + int 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(int, len, (int)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) { + printk(KERN_WARNING "BTRFS: mismatching " + "generation and generation_v2 " + "found in root item. This root " + "was probably mounted with an " + "older kernel. Resetting all " + "new fields.\n"); + } + need_reset = 1; + } + if (need_reset) { + memset(&item->generation_v2, 0, + sizeof(*item) - offsetof(struct btrfs_root_item, + generation_v2)); + + uuid_le_gen(&uuid); + memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE); + } +} + +/* + * 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 reak key of the tree we look for + * + * If ->offset of 'seach_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, 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_path *path; + struct extent_buffer *l; + int ret; + int slot; + unsigned long ptr; + int old_len; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + ret = btrfs_search_slot(trans, root, key, path, 0, 1); + if (ret < 0) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } + + if (ret != 0) { + btrfs_print_leaf(root, path->nodes[0]); + btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu", + key->objectid, key->type, key->offset); + BUG_ON(1); + } + + 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, root, ret); + goto out; + } + + ret = btrfs_del_item(trans, root, path); + if (ret < 0) { + btrfs_abort_transaction(trans, root, 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, root, 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, + 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_root *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; + bool can_recover = true; + + if (tree_root->fs_info->sb->s_flags & MS_RDONLY) + can_recover = false; + + 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++; + + 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_error(tree_root->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, tree_root); + if (err) { + btrfs_error(tree_root->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(root->fs_info, root); + if (err) { + BUG_ON(err == -EEXIST); + btrfs_free_fs_root(root); + break; + } + + if (btrfs_root_refs(&root->root_item) == 0) + btrfs_add_dead_root(root); + } + + btrfs_free_path(path); + return err; +} + +/* drop the root item for 'key' from 'root' */ +int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct btrfs_key *key) +{ + 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, + struct btrfs_root *tree_root, + u64 root_id, u64 ref_id, u64 dirid, u64 *sequence, + const char *name, int name_len) + +{ + 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); + BUG_ON(ret < 0); + if (ret == 0) { + leaf = path->nodes[0]; + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_root_ref); + + WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid); + WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len); + ptr = (unsigned long)(ref + 1); + WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len)); + *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, + struct btrfs_root *tree_root, + u64 root_id, u64 ref_id, u64 dirid, u64 sequence, + const char *name, int name_len) +{ + 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, tree_root, 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 timespec ct = CURRENT_TIME; + + 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); +} -- cgit v1.2.3-54-g00ecf