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![Miao Xie](/assets/img/avatar_default.png)
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
497 lines
13 KiB
C
497 lines
13 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/err.h>
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#include <linux/uuid.h>
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#include "ctree.h"
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#include "transaction.h"
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#include "disk-io.h"
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#include "print-tree.h"
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/*
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* Read a root item from the tree. In case we detect a root item smaller then
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* sizeof(root_item), we know it's an old version of the root structure and
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* initialize all new fields to zero. The same happens if we detect mismatching
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* generation numbers as then we know the root was once mounted with an older
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* kernel that was not aware of the root item structure change.
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*/
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static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
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struct btrfs_root_item *item)
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{
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uuid_le uuid;
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int len;
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int need_reset = 0;
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len = btrfs_item_size_nr(eb, slot);
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read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
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min_t(int, len, (int)sizeof(*item)));
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if (len < sizeof(*item))
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need_reset = 1;
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if (!need_reset && btrfs_root_generation(item)
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!= btrfs_root_generation_v2(item)) {
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if (btrfs_root_generation_v2(item) != 0) {
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printk(KERN_WARNING "BTRFS: mismatching "
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"generation and generation_v2 "
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"found in root item. This root "
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"was probably mounted with an "
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"older kernel. Resetting all "
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"new fields.\n");
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}
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need_reset = 1;
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}
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if (need_reset) {
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memset(&item->generation_v2, 0,
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sizeof(*item) - offsetof(struct btrfs_root_item,
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generation_v2));
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uuid_le_gen(&uuid);
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memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
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}
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}
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/*
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* btrfs_find_root - lookup the root by the key.
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* root: the root of the root tree
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* search_key: the key to search
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* path: the path we search
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* root_item: the root item of the tree we look for
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* root_key: the reak key of the tree we look for
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*
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* If ->offset of 'seach_key' is -1ULL, it means we are not sure the offset
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* of the search key, just lookup the root with the highest offset for a
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* given objectid.
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*
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* If we find something return 0, otherwise > 0, < 0 on error.
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*/
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int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
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struct btrfs_path *path, struct btrfs_root_item *root_item,
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struct btrfs_key *root_key)
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{
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struct btrfs_key found_key;
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struct extent_buffer *l;
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int ret;
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int slot;
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ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
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if (ret < 0)
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return ret;
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if (search_key->offset != -1ULL) { /* the search key is exact */
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if (ret > 0)
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goto out;
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} else {
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BUG_ON(ret == 0); /* Logical error */
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if (path->slots[0] == 0)
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goto out;
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path->slots[0]--;
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ret = 0;
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}
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l = path->nodes[0];
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slot = path->slots[0];
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btrfs_item_key_to_cpu(l, &found_key, slot);
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if (found_key.objectid != search_key->objectid ||
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found_key.type != BTRFS_ROOT_ITEM_KEY) {
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ret = 1;
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goto out;
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}
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if (root_item)
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btrfs_read_root_item(l, slot, root_item);
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if (root_key)
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memcpy(root_key, &found_key, sizeof(found_key));
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out:
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btrfs_release_path(path);
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return ret;
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}
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void btrfs_set_root_node(struct btrfs_root_item *item,
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struct extent_buffer *node)
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{
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btrfs_set_root_bytenr(item, node->start);
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btrfs_set_root_level(item, btrfs_header_level(node));
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btrfs_set_root_generation(item, btrfs_header_generation(node));
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}
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/*
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* copy the data in 'item' into the btree
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*/
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int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, struct btrfs_key *key, struct btrfs_root_item
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*item)
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{
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struct btrfs_path *path;
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struct extent_buffer *l;
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int ret;
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int slot;
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unsigned long ptr;
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int old_len;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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ret = btrfs_search_slot(trans, root, key, path, 0, 1);
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if (ret < 0) {
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btrfs_abort_transaction(trans, root, ret);
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goto out;
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}
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if (ret != 0) {
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btrfs_print_leaf(root, path->nodes[0]);
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btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu",
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key->objectid, key->type, key->offset);
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BUG_ON(1);
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}
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l = path->nodes[0];
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slot = path->slots[0];
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ptr = btrfs_item_ptr_offset(l, slot);
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old_len = btrfs_item_size_nr(l, slot);
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/*
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* If this is the first time we update the root item which originated
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* from an older kernel, we need to enlarge the item size to make room
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* for the added fields.
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*/
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if (old_len < sizeof(*item)) {
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btrfs_release_path(path);
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ret = btrfs_search_slot(trans, root, key, path,
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-1, 1);
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if (ret < 0) {
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btrfs_abort_transaction(trans, root, ret);
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goto out;
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}
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ret = btrfs_del_item(trans, root, path);
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if (ret < 0) {
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btrfs_abort_transaction(trans, root, ret);
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goto out;
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}
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btrfs_release_path(path);
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ret = btrfs_insert_empty_item(trans, root, path,
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key, sizeof(*item));
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if (ret < 0) {
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btrfs_abort_transaction(trans, root, ret);
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goto out;
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}
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l = path->nodes[0];
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slot = path->slots[0];
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ptr = btrfs_item_ptr_offset(l, slot);
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}
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/*
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* Update generation_v2 so at the next mount we know the new root
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* fields are valid.
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*/
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btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
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write_extent_buffer(l, item, ptr, sizeof(*item));
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btrfs_mark_buffer_dirty(path->nodes[0]);
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out:
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
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struct btrfs_key *key, struct btrfs_root_item *item)
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{
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/*
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* Make sure generation v1 and v2 match. See update_root for details.
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*/
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btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
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return btrfs_insert_item(trans, root, key, item, sizeof(*item));
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}
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int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
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{
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struct extent_buffer *leaf;
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_key root_key;
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struct btrfs_root *root;
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int err = 0;
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int ret;
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bool can_recover = true;
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if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
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can_recover = false;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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key.objectid = BTRFS_ORPHAN_OBJECTID;
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key.type = BTRFS_ORPHAN_ITEM_KEY;
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key.offset = 0;
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root_key.type = BTRFS_ROOT_ITEM_KEY;
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root_key.offset = (u64)-1;
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while (1) {
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ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
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if (ret < 0) {
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err = ret;
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break;
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}
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leaf = path->nodes[0];
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if (path->slots[0] >= btrfs_header_nritems(leaf)) {
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ret = btrfs_next_leaf(tree_root, path);
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if (ret < 0)
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err = ret;
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if (ret != 0)
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break;
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leaf = path->nodes[0];
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}
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btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
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btrfs_release_path(path);
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if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
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key.type != BTRFS_ORPHAN_ITEM_KEY)
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break;
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root_key.objectid = key.offset;
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key.offset++;
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root = btrfs_read_fs_root(tree_root, &root_key);
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err = PTR_ERR_OR_ZERO(root);
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if (err && err != -ENOENT) {
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break;
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} else if (err == -ENOENT) {
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struct btrfs_trans_handle *trans;
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btrfs_release_path(path);
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trans = btrfs_join_transaction(tree_root);
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if (IS_ERR(trans)) {
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err = PTR_ERR(trans);
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btrfs_error(tree_root->fs_info, err,
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"Failed to start trans to delete "
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"orphan item");
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break;
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}
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err = btrfs_del_orphan_item(trans, tree_root,
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root_key.objectid);
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btrfs_end_transaction(trans, tree_root);
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if (err) {
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btrfs_error(tree_root->fs_info, err,
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"Failed to delete root orphan "
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"item");
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break;
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}
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continue;
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}
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err = btrfs_init_fs_root(root);
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if (err) {
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btrfs_free_fs_root(root);
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break;
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}
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set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
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err = btrfs_insert_fs_root(root->fs_info, root);
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if (err) {
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BUG_ON(err == -EEXIST);
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btrfs_free_fs_root(root);
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break;
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}
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if (btrfs_root_refs(&root->root_item) == 0)
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btrfs_add_dead_root(root);
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}
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btrfs_free_path(path);
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return err;
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}
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/* drop the root item for 'key' from 'root' */
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int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
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struct btrfs_key *key)
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{
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struct btrfs_path *path;
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int ret;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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ret = btrfs_search_slot(trans, root, key, path, -1, 1);
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if (ret < 0)
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goto out;
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BUG_ON(ret != 0);
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ret = btrfs_del_item(trans, root, path);
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out:
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *tree_root,
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u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
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const char *name, int name_len)
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{
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struct btrfs_path *path;
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struct btrfs_root_ref *ref;
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struct extent_buffer *leaf;
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struct btrfs_key key;
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unsigned long ptr;
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int err = 0;
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int ret;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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key.objectid = root_id;
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key.type = BTRFS_ROOT_BACKREF_KEY;
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key.offset = ref_id;
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again:
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ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
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BUG_ON(ret < 0);
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if (ret == 0) {
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leaf = path->nodes[0];
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ref = btrfs_item_ptr(leaf, path->slots[0],
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struct btrfs_root_ref);
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WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
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WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
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ptr = (unsigned long)(ref + 1);
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WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
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*sequence = btrfs_root_ref_sequence(leaf, ref);
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ret = btrfs_del_item(trans, tree_root, path);
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if (ret) {
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err = ret;
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goto out;
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}
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} else
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err = -ENOENT;
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if (key.type == BTRFS_ROOT_BACKREF_KEY) {
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btrfs_release_path(path);
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key.objectid = ref_id;
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key.type = BTRFS_ROOT_REF_KEY;
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key.offset = root_id;
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goto again;
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}
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out:
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btrfs_free_path(path);
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return err;
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}
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/*
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* add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
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* or BTRFS_ROOT_BACKREF_KEY.
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*
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* The dirid, sequence, name and name_len refer to the directory entry
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* that is referencing the root.
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*
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* For a forward ref, the root_id is the id of the tree referencing
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* the root and ref_id is the id of the subvol or snapshot.
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*
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* For a back ref the root_id is the id of the subvol or snapshot and
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* ref_id is the id of the tree referencing it.
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*
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* Will return 0, -ENOMEM, or anything from the CoW path
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*/
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int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *tree_root,
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u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
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const char *name, int name_len)
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{
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struct btrfs_key key;
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int ret;
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struct btrfs_path *path;
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struct btrfs_root_ref *ref;
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struct extent_buffer *leaf;
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unsigned long ptr;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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key.objectid = root_id;
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key.type = BTRFS_ROOT_BACKREF_KEY;
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key.offset = ref_id;
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again:
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ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
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sizeof(*ref) + name_len);
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if (ret) {
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btrfs_abort_transaction(trans, tree_root, ret);
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btrfs_free_path(path);
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return ret;
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}
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leaf = path->nodes[0];
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ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
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btrfs_set_root_ref_dirid(leaf, ref, dirid);
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btrfs_set_root_ref_sequence(leaf, ref, sequence);
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btrfs_set_root_ref_name_len(leaf, ref, name_len);
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ptr = (unsigned long)(ref + 1);
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write_extent_buffer(leaf, name, ptr, name_len);
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btrfs_mark_buffer_dirty(leaf);
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if (key.type == BTRFS_ROOT_BACKREF_KEY) {
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btrfs_release_path(path);
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key.objectid = ref_id;
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key.type = BTRFS_ROOT_REF_KEY;
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key.offset = root_id;
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goto again;
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}
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btrfs_free_path(path);
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return 0;
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}
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/*
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* Old btrfs forgets to init root_item->flags and root_item->byte_limit
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* for subvolumes. To work around this problem, we steal a bit from
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* root_item->inode_item->flags, and use it to indicate if those fields
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* have been properly initialized.
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*/
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void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
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{
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u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
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if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
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inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
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btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
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btrfs_set_root_flags(root_item, 0);
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btrfs_set_root_limit(root_item, 0);
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}
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}
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void btrfs_update_root_times(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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struct btrfs_root_item *item = &root->root_item;
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struct timespec ct = CURRENT_TIME;
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spin_lock(&root->root_item_lock);
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btrfs_set_root_ctransid(item, trans->transid);
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btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
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btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
|
|
spin_unlock(&root->root_item_lock);
|
|
}
|