![Jan Schmidt](/assets/img/avatar_default.png)
inode_ref_info() returns 1 when the element wasn't found and < 0 on error, just like btrfs_search_slot(). In iref_to_path() it's an error when the inode ref can't be found, thus we return ERR_PTR(ret) in that case. In order to avoid ERR_PTR(1), we now set ret to -ENOENT in that case. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
1404 lines
36 KiB
C
1404 lines
36 KiB
C
/*
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* Copyright (C) 2011 STRATO. 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 "ctree.h"
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#include "disk-io.h"
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#include "backref.h"
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#include "ulist.h"
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#include "transaction.h"
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#include "delayed-ref.h"
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/*
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* this structure records all encountered refs on the way up to the root
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*/
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struct __prelim_ref {
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struct list_head list;
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u64 root_id;
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struct btrfs_key key;
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int level;
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int count;
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u64 parent;
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u64 wanted_disk_byte;
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};
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static int __add_prelim_ref(struct list_head *head, u64 root_id,
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struct btrfs_key *key, int level, u64 parent,
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u64 wanted_disk_byte, int count)
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{
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struct __prelim_ref *ref;
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/* in case we're adding delayed refs, we're holding the refs spinlock */
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ref = kmalloc(sizeof(*ref), GFP_ATOMIC);
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if (!ref)
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return -ENOMEM;
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ref->root_id = root_id;
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if (key)
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ref->key = *key;
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else
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memset(&ref->key, 0, sizeof(ref->key));
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ref->level = level;
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ref->count = count;
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ref->parent = parent;
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ref->wanted_disk_byte = wanted_disk_byte;
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list_add_tail(&ref->list, head);
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return 0;
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}
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static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
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struct ulist *parents,
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struct extent_buffer *eb, int level,
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u64 wanted_objectid, u64 wanted_disk_byte)
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{
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int ret;
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int slot;
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struct btrfs_file_extent_item *fi;
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struct btrfs_key key;
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u64 disk_byte;
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add_parent:
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ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
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if (ret < 0)
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return ret;
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if (level != 0)
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return 0;
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/*
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* if the current leaf is full with EXTENT_DATA items, we must
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* check the next one if that holds a reference as well.
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* ref->count cannot be used to skip this check.
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* repeat this until we don't find any additional EXTENT_DATA items.
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*/
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while (1) {
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ret = btrfs_next_leaf(root, path);
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if (ret < 0)
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return ret;
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if (ret)
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return 0;
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eb = path->nodes[0];
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for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) {
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btrfs_item_key_to_cpu(eb, &key, slot);
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if (key.objectid != wanted_objectid ||
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key.type != BTRFS_EXTENT_DATA_KEY)
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return 0;
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fi = btrfs_item_ptr(eb, slot,
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struct btrfs_file_extent_item);
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disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
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if (disk_byte == wanted_disk_byte)
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goto add_parent;
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}
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}
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return 0;
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}
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/*
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* resolve an indirect backref in the form (root_id, key, level)
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* to a logical address
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*/
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static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
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struct __prelim_ref *ref,
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struct ulist *parents)
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{
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struct btrfs_path *path;
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struct btrfs_root *root;
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struct btrfs_key root_key;
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struct btrfs_key key = {0};
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struct extent_buffer *eb;
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int ret = 0;
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int root_level;
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int level = ref->level;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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root_key.objectid = ref->root_id;
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root_key.type = BTRFS_ROOT_ITEM_KEY;
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root_key.offset = (u64)-1;
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root = btrfs_read_fs_root_no_name(fs_info, &root_key);
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if (IS_ERR(root)) {
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ret = PTR_ERR(root);
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goto out;
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}
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rcu_read_lock();
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root_level = btrfs_header_level(root->node);
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rcu_read_unlock();
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if (root_level + 1 == level)
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goto out;
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path->lowest_level = level;
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ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0);
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pr_debug("search slot in root %llu (level %d, ref count %d) returned "
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"%d for key (%llu %u %llu)\n",
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(unsigned long long)ref->root_id, level, ref->count, ret,
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(unsigned long long)ref->key.objectid, ref->key.type,
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(unsigned long long)ref->key.offset);
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if (ret < 0)
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goto out;
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eb = path->nodes[level];
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if (!eb) {
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WARN_ON(1);
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ret = 1;
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goto out;
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}
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if (level == 0) {
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if (ret == 1 && path->slots[0] >= btrfs_header_nritems(eb)) {
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ret = btrfs_next_leaf(root, path);
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if (ret)
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goto out;
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eb = path->nodes[0];
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}
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btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
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}
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/* the last two parameters will only be used for level == 0 */
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ret = add_all_parents(root, path, parents, eb, level, key.objectid,
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ref->wanted_disk_byte);
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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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/*
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* resolve all indirect backrefs from the list
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*/
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static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
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struct list_head *head)
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{
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int err;
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int ret = 0;
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struct __prelim_ref *ref;
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struct __prelim_ref *ref_safe;
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struct __prelim_ref *new_ref;
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struct ulist *parents;
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struct ulist_node *node;
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parents = ulist_alloc(GFP_NOFS);
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if (!parents)
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return -ENOMEM;
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/*
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* _safe allows us to insert directly after the current item without
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* iterating over the newly inserted items.
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* we're also allowed to re-assign ref during iteration.
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*/
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list_for_each_entry_safe(ref, ref_safe, head, list) {
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if (ref->parent) /* already direct */
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continue;
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if (ref->count == 0)
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continue;
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err = __resolve_indirect_ref(fs_info, ref, parents);
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if (err) {
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if (ret == 0)
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ret = err;
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continue;
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}
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/* we put the first parent into the ref at hand */
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node = ulist_next(parents, NULL);
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ref->parent = node ? node->val : 0;
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/* additional parents require new refs being added here */
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while ((node = ulist_next(parents, node))) {
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new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
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if (!new_ref) {
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ret = -ENOMEM;
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break;
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}
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memcpy(new_ref, ref, sizeof(*ref));
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new_ref->parent = node->val;
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list_add(&new_ref->list, &ref->list);
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}
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ulist_reinit(parents);
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}
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ulist_free(parents);
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return ret;
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}
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/*
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* merge two lists of backrefs and adjust counts accordingly
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*
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* mode = 1: merge identical keys, if key is set
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* mode = 2: merge identical parents
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*/
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static int __merge_refs(struct list_head *head, int mode)
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{
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struct list_head *pos1;
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list_for_each(pos1, head) {
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struct list_head *n2;
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struct list_head *pos2;
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struct __prelim_ref *ref1;
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ref1 = list_entry(pos1, struct __prelim_ref, list);
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if (mode == 1 && ref1->key.type == 0)
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continue;
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for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
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pos2 = n2, n2 = pos2->next) {
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struct __prelim_ref *ref2;
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ref2 = list_entry(pos2, struct __prelim_ref, list);
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if (mode == 1) {
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if (memcmp(&ref1->key, &ref2->key,
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sizeof(ref1->key)) ||
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ref1->level != ref2->level ||
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ref1->root_id != ref2->root_id)
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continue;
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ref1->count += ref2->count;
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} else {
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if (ref1->parent != ref2->parent)
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continue;
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ref1->count += ref2->count;
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}
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list_del(&ref2->list);
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kfree(ref2);
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}
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}
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return 0;
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}
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/*
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* add all currently queued delayed refs from this head whose seq nr is
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* smaller or equal that seq to the list
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*/
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static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
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struct btrfs_key *info_key,
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struct list_head *prefs)
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{
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struct btrfs_delayed_extent_op *extent_op = head->extent_op;
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struct rb_node *n = &head->node.rb_node;
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int sgn;
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int ret = 0;
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if (extent_op && extent_op->update_key)
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btrfs_disk_key_to_cpu(info_key, &extent_op->key);
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while ((n = rb_prev(n))) {
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struct btrfs_delayed_ref_node *node;
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node = rb_entry(n, struct btrfs_delayed_ref_node,
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rb_node);
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if (node->bytenr != head->node.bytenr)
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break;
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WARN_ON(node->is_head);
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if (node->seq > seq)
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continue;
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switch (node->action) {
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case BTRFS_ADD_DELAYED_EXTENT:
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case BTRFS_UPDATE_DELAYED_HEAD:
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WARN_ON(1);
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continue;
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case BTRFS_ADD_DELAYED_REF:
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sgn = 1;
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break;
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case BTRFS_DROP_DELAYED_REF:
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sgn = -1;
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break;
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default:
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BUG_ON(1);
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}
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switch (node->type) {
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case BTRFS_TREE_BLOCK_REF_KEY: {
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struct btrfs_delayed_tree_ref *ref;
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ref = btrfs_delayed_node_to_tree_ref(node);
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ret = __add_prelim_ref(prefs, ref->root, info_key,
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ref->level + 1, 0, node->bytenr,
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node->ref_mod * sgn);
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break;
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}
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case BTRFS_SHARED_BLOCK_REF_KEY: {
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struct btrfs_delayed_tree_ref *ref;
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ref = btrfs_delayed_node_to_tree_ref(node);
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ret = __add_prelim_ref(prefs, ref->root, info_key,
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ref->level + 1, ref->parent,
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node->bytenr,
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node->ref_mod * sgn);
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break;
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}
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case BTRFS_EXTENT_DATA_REF_KEY: {
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struct btrfs_delayed_data_ref *ref;
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struct btrfs_key key;
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ref = btrfs_delayed_node_to_data_ref(node);
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key.objectid = ref->objectid;
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = ref->offset;
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ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
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node->bytenr,
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node->ref_mod * sgn);
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break;
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}
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case BTRFS_SHARED_DATA_REF_KEY: {
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struct btrfs_delayed_data_ref *ref;
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struct btrfs_key key;
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ref = btrfs_delayed_node_to_data_ref(node);
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key.objectid = ref->objectid;
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = ref->offset;
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ret = __add_prelim_ref(prefs, ref->root, &key, 0,
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ref->parent, node->bytenr,
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node->ref_mod * sgn);
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break;
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}
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default:
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WARN_ON(1);
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}
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BUG_ON(ret);
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}
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return 0;
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}
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/*
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* add all inline backrefs for bytenr to the list
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*/
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static int __add_inline_refs(struct btrfs_fs_info *fs_info,
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struct btrfs_path *path, u64 bytenr,
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struct btrfs_key *info_key, int *info_level,
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struct list_head *prefs)
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{
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int ret = 0;
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int slot;
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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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unsigned long end;
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struct btrfs_extent_item *ei;
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u64 flags;
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u64 item_size;
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/*
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* enumerate all inline refs
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*/
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leaf = path->nodes[0];
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slot = path->slots[0] - 1;
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item_size = btrfs_item_size_nr(leaf, slot);
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BUG_ON(item_size < sizeof(*ei));
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ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
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flags = btrfs_extent_flags(leaf, ei);
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ptr = (unsigned long)(ei + 1);
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end = (unsigned long)ei + item_size;
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if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
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struct btrfs_tree_block_info *info;
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struct btrfs_disk_key disk_key;
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info = (struct btrfs_tree_block_info *)ptr;
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*info_level = btrfs_tree_block_level(leaf, info);
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btrfs_tree_block_key(leaf, info, &disk_key);
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btrfs_disk_key_to_cpu(info_key, &disk_key);
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ptr += sizeof(struct btrfs_tree_block_info);
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BUG_ON(ptr > end);
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} else {
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BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
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}
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while (ptr < end) {
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struct btrfs_extent_inline_ref *iref;
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u64 offset;
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int type;
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iref = (struct btrfs_extent_inline_ref *)ptr;
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type = btrfs_extent_inline_ref_type(leaf, iref);
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offset = btrfs_extent_inline_ref_offset(leaf, iref);
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switch (type) {
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case BTRFS_SHARED_BLOCK_REF_KEY:
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ret = __add_prelim_ref(prefs, 0, info_key,
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*info_level + 1, offset,
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bytenr, 1);
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break;
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case BTRFS_SHARED_DATA_REF_KEY: {
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struct btrfs_shared_data_ref *sdref;
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int count;
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sdref = (struct btrfs_shared_data_ref *)(iref + 1);
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count = btrfs_shared_data_ref_count(leaf, sdref);
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ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
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bytenr, count);
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break;
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}
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case BTRFS_TREE_BLOCK_REF_KEY:
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ret = __add_prelim_ref(prefs, offset, info_key,
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*info_level + 1, 0, bytenr, 1);
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break;
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case BTRFS_EXTENT_DATA_REF_KEY: {
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struct btrfs_extent_data_ref *dref;
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int count;
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u64 root;
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dref = (struct btrfs_extent_data_ref *)(&iref->offset);
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count = btrfs_extent_data_ref_count(leaf, dref);
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key.objectid = btrfs_extent_data_ref_objectid(leaf,
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dref);
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = btrfs_extent_data_ref_offset(leaf, dref);
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root = btrfs_extent_data_ref_root(leaf, dref);
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ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr,
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count);
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break;
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}
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default:
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WARN_ON(1);
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}
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BUG_ON(ret);
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ptr += btrfs_extent_inline_ref_size(type);
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}
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|
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return 0;
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}
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|
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/*
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* add all non-inline backrefs for bytenr to the list
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*/
|
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static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
|
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struct btrfs_path *path, u64 bytenr,
|
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struct btrfs_key *info_key, int info_level,
|
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struct list_head *prefs)
|
|
{
|
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struct btrfs_root *extent_root = fs_info->extent_root;
|
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int ret;
|
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int slot;
|
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struct extent_buffer *leaf;
|
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struct btrfs_key key;
|
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|
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while (1) {
|
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ret = btrfs_next_item(extent_root, path);
|
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if (ret < 0)
|
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break;
|
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if (ret) {
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ret = 0;
|
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break;
|
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}
|
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|
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slot = path->slots[0];
|
|
leaf = path->nodes[0];
|
|
btrfs_item_key_to_cpu(leaf, &key, slot);
|
|
|
|
if (key.objectid != bytenr)
|
|
break;
|
|
if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
|
|
continue;
|
|
if (key.type > BTRFS_SHARED_DATA_REF_KEY)
|
|
break;
|
|
|
|
switch (key.type) {
|
|
case BTRFS_SHARED_BLOCK_REF_KEY:
|
|
ret = __add_prelim_ref(prefs, 0, info_key,
|
|
info_level + 1, key.offset,
|
|
bytenr, 1);
|
|
break;
|
|
case BTRFS_SHARED_DATA_REF_KEY: {
|
|
struct btrfs_shared_data_ref *sdref;
|
|
int count;
|
|
|
|
sdref = btrfs_item_ptr(leaf, slot,
|
|
struct btrfs_shared_data_ref);
|
|
count = btrfs_shared_data_ref_count(leaf, sdref);
|
|
ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
|
|
bytenr, count);
|
|
break;
|
|
}
|
|
case BTRFS_TREE_BLOCK_REF_KEY:
|
|
ret = __add_prelim_ref(prefs, key.offset, info_key,
|
|
info_level + 1, 0, bytenr, 1);
|
|
break;
|
|
case BTRFS_EXTENT_DATA_REF_KEY: {
|
|
struct btrfs_extent_data_ref *dref;
|
|
int count;
|
|
u64 root;
|
|
|
|
dref = btrfs_item_ptr(leaf, slot,
|
|
struct btrfs_extent_data_ref);
|
|
count = btrfs_extent_data_ref_count(leaf, dref);
|
|
key.objectid = btrfs_extent_data_ref_objectid(leaf,
|
|
dref);
|
|
key.type = BTRFS_EXTENT_DATA_KEY;
|
|
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
|
|
root = btrfs_extent_data_ref_root(leaf, dref);
|
|
ret = __add_prelim_ref(prefs, root, &key, 0, 0,
|
|
bytenr, count);
|
|
break;
|
|
}
|
|
default:
|
|
WARN_ON(1);
|
|
}
|
|
BUG_ON(ret);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this adds all existing backrefs (inline backrefs, backrefs and delayed
|
|
* refs) for the given bytenr to the refs list, merges duplicates and resolves
|
|
* indirect refs to their parent bytenr.
|
|
* When roots are found, they're added to the roots list
|
|
*
|
|
* FIXME some caching might speed things up
|
|
*/
|
|
static int find_parent_nodes(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 seq, struct ulist *refs, struct ulist *roots)
|
|
{
|
|
struct btrfs_key key;
|
|
struct btrfs_path *path;
|
|
struct btrfs_key info_key = { 0 };
|
|
struct btrfs_delayed_ref_root *delayed_refs = NULL;
|
|
struct btrfs_delayed_ref_head *head = NULL;
|
|
int info_level = 0;
|
|
int ret;
|
|
struct list_head prefs_delayed;
|
|
struct list_head prefs;
|
|
struct __prelim_ref *ref;
|
|
|
|
INIT_LIST_HEAD(&prefs);
|
|
INIT_LIST_HEAD(&prefs_delayed);
|
|
|
|
key.objectid = bytenr;
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
key.offset = (u64)-1;
|
|
|
|
path = btrfs_alloc_path();
|
|
if (!path)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* grab both a lock on the path and a lock on the delayed ref head.
|
|
* We need both to get a consistent picture of how the refs look
|
|
* at a specified point in time
|
|
*/
|
|
again:
|
|
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
goto out;
|
|
BUG_ON(ret == 0);
|
|
|
|
/*
|
|
* look if there are updates for this ref queued and lock the head
|
|
*/
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
spin_lock(&delayed_refs->lock);
|
|
head = btrfs_find_delayed_ref_head(trans, bytenr);
|
|
if (head) {
|
|
if (!mutex_trylock(&head->mutex)) {
|
|
atomic_inc(&head->node.refs);
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
btrfs_release_path(path);
|
|
|
|
/*
|
|
* Mutex was contended, block until it's
|
|
* released and try again
|
|
*/
|
|
mutex_lock(&head->mutex);
|
|
mutex_unlock(&head->mutex);
|
|
btrfs_put_delayed_ref(&head->node);
|
|
goto again;
|
|
}
|
|
ret = __add_delayed_refs(head, seq, &info_key, &prefs_delayed);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
if (path->slots[0]) {
|
|
struct extent_buffer *leaf;
|
|
int slot;
|
|
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0] - 1;
|
|
btrfs_item_key_to_cpu(leaf, &key, slot);
|
|
if (key.objectid == bytenr &&
|
|
key.type == BTRFS_EXTENT_ITEM_KEY) {
|
|
ret = __add_inline_refs(fs_info, path, bytenr,
|
|
&info_key, &info_level, &prefs);
|
|
if (ret)
|
|
goto out;
|
|
ret = __add_keyed_refs(fs_info, path, bytenr, &info_key,
|
|
info_level, &prefs);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
}
|
|
btrfs_release_path(path);
|
|
|
|
/*
|
|
* when adding the delayed refs above, the info_key might not have
|
|
* been known yet. Go over the list and replace the missing keys
|
|
*/
|
|
list_for_each_entry(ref, &prefs_delayed, list) {
|
|
if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0)
|
|
memcpy(&ref->key, &info_key, sizeof(ref->key));
|
|
}
|
|
list_splice_init(&prefs_delayed, &prefs);
|
|
|
|
ret = __merge_refs(&prefs, 1);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = __resolve_indirect_refs(fs_info, &prefs);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = __merge_refs(&prefs, 2);
|
|
if (ret)
|
|
goto out;
|
|
|
|
while (!list_empty(&prefs)) {
|
|
ref = list_first_entry(&prefs, struct __prelim_ref, list);
|
|
list_del(&ref->list);
|
|
if (ref->count < 0)
|
|
WARN_ON(1);
|
|
if (ref->count && ref->root_id && ref->parent == 0) {
|
|
/* no parent == root of tree */
|
|
ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
if (ref->count && ref->parent) {
|
|
ret = ulist_add(refs, ref->parent, 0, GFP_NOFS);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
kfree(ref);
|
|
}
|
|
|
|
out:
|
|
if (head)
|
|
mutex_unlock(&head->mutex);
|
|
btrfs_free_path(path);
|
|
while (!list_empty(&prefs)) {
|
|
ref = list_first_entry(&prefs, struct __prelim_ref, list);
|
|
list_del(&ref->list);
|
|
kfree(ref);
|
|
}
|
|
while (!list_empty(&prefs_delayed)) {
|
|
ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
|
|
list);
|
|
list_del(&ref->list);
|
|
kfree(ref);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Finds all leafs with a reference to the specified combination of bytenr and
|
|
* offset. key_list_head will point to a list of corresponding keys (caller must
|
|
* free each list element). The leafs will be stored in the leafs ulist, which
|
|
* must be freed with ulist_free.
|
|
*
|
|
* returns 0 on success, <0 on error
|
|
*/
|
|
static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 num_bytes, u64 seq, struct ulist **leafs)
|
|
{
|
|
struct ulist *tmp;
|
|
int ret;
|
|
|
|
tmp = ulist_alloc(GFP_NOFS);
|
|
if (!tmp)
|
|
return -ENOMEM;
|
|
*leafs = ulist_alloc(GFP_NOFS);
|
|
if (!*leafs) {
|
|
ulist_free(tmp);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp);
|
|
ulist_free(tmp);
|
|
|
|
if (ret < 0 && ret != -ENOENT) {
|
|
ulist_free(*leafs);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* walk all backrefs for a given extent to find all roots that reference this
|
|
* extent. Walking a backref means finding all extents that reference this
|
|
* extent and in turn walk the backrefs of those, too. Naturally this is a
|
|
* recursive process, but here it is implemented in an iterative fashion: We
|
|
* find all referencing extents for the extent in question and put them on a
|
|
* list. In turn, we find all referencing extents for those, further appending
|
|
* to the list. The way we iterate the list allows adding more elements after
|
|
* the current while iterating. The process stops when we reach the end of the
|
|
* list. Found roots are added to the roots list.
|
|
*
|
|
* returns 0 on success, < 0 on error.
|
|
*/
|
|
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
|
|
struct btrfs_fs_info *fs_info, u64 bytenr,
|
|
u64 num_bytes, u64 seq, struct ulist **roots)
|
|
{
|
|
struct ulist *tmp;
|
|
struct ulist_node *node = NULL;
|
|
int ret;
|
|
|
|
tmp = ulist_alloc(GFP_NOFS);
|
|
if (!tmp)
|
|
return -ENOMEM;
|
|
*roots = ulist_alloc(GFP_NOFS);
|
|
if (!*roots) {
|
|
ulist_free(tmp);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
while (1) {
|
|
ret = find_parent_nodes(trans, fs_info, bytenr, seq,
|
|
tmp, *roots);
|
|
if (ret < 0 && ret != -ENOENT) {
|
|
ulist_free(tmp);
|
|
ulist_free(*roots);
|
|
return ret;
|
|
}
|
|
node = ulist_next(tmp, node);
|
|
if (!node)
|
|
break;
|
|
bytenr = node->val;
|
|
}
|
|
|
|
ulist_free(tmp);
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int __inode_info(u64 inum, u64 ioff, u8 key_type,
|
|
struct btrfs_root *fs_root, struct btrfs_path *path,
|
|
struct btrfs_key *found_key)
|
|
{
|
|
int ret;
|
|
struct btrfs_key key;
|
|
struct extent_buffer *eb;
|
|
|
|
key.type = key_type;
|
|
key.objectid = inum;
|
|
key.offset = ioff;
|
|
|
|
ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
eb = path->nodes[0];
|
|
if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
|
|
ret = btrfs_next_leaf(fs_root, path);
|
|
if (ret)
|
|
return ret;
|
|
eb = path->nodes[0];
|
|
}
|
|
|
|
btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
|
|
if (found_key->type != key.type || found_key->objectid != key.objectid)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this makes the path point to (inum INODE_ITEM ioff)
|
|
*/
|
|
int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path)
|
|
{
|
|
struct btrfs_key key;
|
|
return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path,
|
|
&key);
|
|
}
|
|
|
|
static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *found_key)
|
|
{
|
|
return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path,
|
|
found_key);
|
|
}
|
|
|
|
/*
|
|
* this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
|
|
* of the path are separated by '/' and the path is guaranteed to be
|
|
* 0-terminated. the path is only given within the current file system.
|
|
* Therefore, it never starts with a '/'. the caller is responsible to provide
|
|
* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
|
|
* the start point of the resulting string is returned. this pointer is within
|
|
* dest, normally.
|
|
* in case the path buffer would overflow, the pointer is decremented further
|
|
* as if output was written to the buffer, though no more output is actually
|
|
* generated. that way, the caller can determine how much space would be
|
|
* required for the path to fit into the buffer. in that case, the returned
|
|
* value will be smaller than dest. callers must check this!
|
|
*/
|
|
static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
|
|
struct btrfs_inode_ref *iref,
|
|
struct extent_buffer *eb_in, u64 parent,
|
|
char *dest, u32 size)
|
|
{
|
|
u32 len;
|
|
int slot;
|
|
u64 next_inum;
|
|
int ret;
|
|
s64 bytes_left = size - 1;
|
|
struct extent_buffer *eb = eb_in;
|
|
struct btrfs_key found_key;
|
|
|
|
if (bytes_left >= 0)
|
|
dest[bytes_left] = '\0';
|
|
|
|
while (1) {
|
|
len = btrfs_inode_ref_name_len(eb, iref);
|
|
bytes_left -= len;
|
|
if (bytes_left >= 0)
|
|
read_extent_buffer(eb, dest + bytes_left,
|
|
(unsigned long)(iref + 1), len);
|
|
if (eb != eb_in)
|
|
free_extent_buffer(eb);
|
|
ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
|
|
if (ret > 0)
|
|
ret = -ENOENT;
|
|
if (ret)
|
|
break;
|
|
next_inum = found_key.offset;
|
|
|
|
/* regular exit ahead */
|
|
if (parent == next_inum)
|
|
break;
|
|
|
|
slot = path->slots[0];
|
|
eb = path->nodes[0];
|
|
/* make sure we can use eb after releasing the path */
|
|
if (eb != eb_in)
|
|
atomic_inc(&eb->refs);
|
|
btrfs_release_path(path);
|
|
|
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
|
|
parent = next_inum;
|
|
--bytes_left;
|
|
if (bytes_left >= 0)
|
|
dest[bytes_left] = '/';
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
return dest + bytes_left;
|
|
}
|
|
|
|
/*
|
|
* this makes the path point to (logical EXTENT_ITEM *)
|
|
* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
|
|
* tree blocks and <0 on error.
|
|
*/
|
|
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
|
|
struct btrfs_path *path, struct btrfs_key *found_key)
|
|
{
|
|
int ret;
|
|
u64 flags;
|
|
u32 item_size;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_extent_item *ei;
|
|
struct btrfs_key key;
|
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
key.objectid = logical;
|
|
key.offset = (u64)-1;
|
|
|
|
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
ret = btrfs_previous_item(fs_info->extent_root, path,
|
|
0, BTRFS_EXTENT_ITEM_KEY);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
|
|
if (found_key->type != BTRFS_EXTENT_ITEM_KEY ||
|
|
found_key->objectid > logical ||
|
|
found_key->objectid + found_key->offset <= logical) {
|
|
pr_debug("logical %llu is not within any extent\n",
|
|
(unsigned long long)logical);
|
|
return -ENOENT;
|
|
}
|
|
|
|
eb = path->nodes[0];
|
|
item_size = btrfs_item_size_nr(eb, path->slots[0]);
|
|
BUG_ON(item_size < sizeof(*ei));
|
|
|
|
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
|
|
flags = btrfs_extent_flags(eb, ei);
|
|
|
|
pr_debug("logical %llu is at position %llu within the extent (%llu "
|
|
"EXTENT_ITEM %llu) flags %#llx size %u\n",
|
|
(unsigned long long)logical,
|
|
(unsigned long long)(logical - found_key->objectid),
|
|
(unsigned long long)found_key->objectid,
|
|
(unsigned long long)found_key->offset,
|
|
(unsigned long long)flags, item_size);
|
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
|
|
return BTRFS_EXTENT_FLAG_TREE_BLOCK;
|
|
if (flags & BTRFS_EXTENT_FLAG_DATA)
|
|
return BTRFS_EXTENT_FLAG_DATA;
|
|
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* helper function to iterate extent inline refs. ptr must point to a 0 value
|
|
* for the first call and may be modified. it is used to track state.
|
|
* if more refs exist, 0 is returned and the next call to
|
|
* __get_extent_inline_ref must pass the modified ptr parameter to get the
|
|
* next ref. after the last ref was processed, 1 is returned.
|
|
* returns <0 on error
|
|
*/
|
|
static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
|
|
struct btrfs_extent_item *ei, u32 item_size,
|
|
struct btrfs_extent_inline_ref **out_eiref,
|
|
int *out_type)
|
|
{
|
|
unsigned long end;
|
|
u64 flags;
|
|
struct btrfs_tree_block_info *info;
|
|
|
|
if (!*ptr) {
|
|
/* first call */
|
|
flags = btrfs_extent_flags(eb, ei);
|
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
|
|
info = (struct btrfs_tree_block_info *)(ei + 1);
|
|
*out_eiref =
|
|
(struct btrfs_extent_inline_ref *)(info + 1);
|
|
} else {
|
|
*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
|
|
}
|
|
*ptr = (unsigned long)*out_eiref;
|
|
if ((void *)*ptr >= (void *)ei + item_size)
|
|
return -ENOENT;
|
|
}
|
|
|
|
end = (unsigned long)ei + item_size;
|
|
*out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
|
|
*out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
|
|
|
|
*ptr += btrfs_extent_inline_ref_size(*out_type);
|
|
WARN_ON(*ptr > end);
|
|
if (*ptr == end)
|
|
return 1; /* last */
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* reads the tree block backref for an extent. tree level and root are returned
|
|
* through out_level and out_root. ptr must point to a 0 value for the first
|
|
* call and may be modified (see __get_extent_inline_ref comment).
|
|
* returns 0 if data was provided, 1 if there was no more data to provide or
|
|
* <0 on error.
|
|
*/
|
|
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
|
|
struct btrfs_extent_item *ei, u32 item_size,
|
|
u64 *out_root, u8 *out_level)
|
|
{
|
|
int ret;
|
|
int type;
|
|
struct btrfs_tree_block_info *info;
|
|
struct btrfs_extent_inline_ref *eiref;
|
|
|
|
if (*ptr == (unsigned long)-1)
|
|
return 1;
|
|
|
|
while (1) {
|
|
ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
|
|
&eiref, &type);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
|
|
type == BTRFS_SHARED_BLOCK_REF_KEY)
|
|
break;
|
|
|
|
if (ret == 1)
|
|
return 1;
|
|
}
|
|
|
|
/* we can treat both ref types equally here */
|
|
info = (struct btrfs_tree_block_info *)(ei + 1);
|
|
*out_root = btrfs_extent_inline_ref_offset(eb, eiref);
|
|
*out_level = btrfs_tree_block_level(eb, info);
|
|
|
|
if (ret == 1)
|
|
*ptr = (unsigned long)-1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int iterate_leaf_refs(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path, u64 logical,
|
|
u64 orig_extent_item_objectid,
|
|
u64 extent_item_pos, u64 root,
|
|
iterate_extent_inodes_t *iterate, void *ctx)
|
|
{
|
|
u64 disk_byte;
|
|
struct btrfs_key key;
|
|
struct btrfs_file_extent_item *fi;
|
|
struct extent_buffer *eb;
|
|
int slot;
|
|
int nritems;
|
|
int ret = 0;
|
|
int extent_type;
|
|
u64 data_offset;
|
|
u64 data_len;
|
|
|
|
eb = read_tree_block(fs_info->tree_root, logical,
|
|
fs_info->tree_root->leafsize, 0);
|
|
if (!eb)
|
|
return -EIO;
|
|
|
|
/*
|
|
* from the shared data ref, we only have the leaf but we need
|
|
* the key. thus, we must look into all items and see that we
|
|
* find one (some) with a reference to our extent item.
|
|
*/
|
|
nritems = btrfs_header_nritems(eb);
|
|
for (slot = 0; slot < nritems; ++slot) {
|
|
btrfs_item_key_to_cpu(eb, &key, slot);
|
|
if (key.type != BTRFS_EXTENT_DATA_KEY)
|
|
continue;
|
|
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
|
|
extent_type = btrfs_file_extent_type(eb, fi);
|
|
if (extent_type == BTRFS_FILE_EXTENT_INLINE)
|
|
continue;
|
|
/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
|
|
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
|
|
if (disk_byte != orig_extent_item_objectid)
|
|
continue;
|
|
|
|
data_offset = btrfs_file_extent_offset(eb, fi);
|
|
data_len = btrfs_file_extent_num_bytes(eb, fi);
|
|
|
|
if (extent_item_pos < data_offset ||
|
|
extent_item_pos >= data_offset + data_len)
|
|
continue;
|
|
|
|
pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
|
|
"root %llu\n", orig_extent_item_objectid,
|
|
key.objectid, key.offset, root);
|
|
ret = iterate(key.objectid,
|
|
key.offset + (extent_item_pos - data_offset),
|
|
root, ctx);
|
|
if (ret) {
|
|
pr_debug("stopping iteration because ret=%d\n", ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
free_extent_buffer(eb);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* calls iterate() for every inode that references the extent identified by
|
|
* the given parameters.
|
|
* when the iterator function returns a non-zero value, iteration stops.
|
|
* path is guaranteed to be in released state when iterate() is called.
|
|
*/
|
|
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
u64 extent_item_objectid, u64 extent_item_pos,
|
|
iterate_extent_inodes_t *iterate, void *ctx)
|
|
{
|
|
int ret;
|
|
struct list_head data_refs = LIST_HEAD_INIT(data_refs);
|
|
struct list_head shared_refs = LIST_HEAD_INIT(shared_refs);
|
|
struct btrfs_trans_handle *trans;
|
|
struct ulist *refs;
|
|
struct ulist *roots;
|
|
struct ulist_node *ref_node = NULL;
|
|
struct ulist_node *root_node = NULL;
|
|
struct seq_list seq_elem;
|
|
struct btrfs_delayed_ref_root *delayed_refs;
|
|
|
|
trans = btrfs_join_transaction(fs_info->extent_root);
|
|
if (IS_ERR(trans))
|
|
return PTR_ERR(trans);
|
|
|
|
pr_debug("resolving all inodes for extent %llu\n",
|
|
extent_item_objectid);
|
|
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
spin_lock(&delayed_refs->lock);
|
|
btrfs_get_delayed_seq(delayed_refs, &seq_elem);
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
|
|
extent_item_pos, seq_elem.seq,
|
|
&refs);
|
|
|
|
if (ret)
|
|
goto out;
|
|
|
|
while (!ret && (ref_node = ulist_next(refs, ref_node))) {
|
|
ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1,
|
|
seq_elem.seq, &roots);
|
|
if (ret)
|
|
break;
|
|
while (!ret && (root_node = ulist_next(roots, root_node))) {
|
|
pr_debug("root %llu references leaf %llu\n",
|
|
root_node->val, ref_node->val);
|
|
ret = iterate_leaf_refs(fs_info, path, ref_node->val,
|
|
extent_item_objectid,
|
|
extent_item_pos, root_node->val,
|
|
iterate, ctx);
|
|
}
|
|
}
|
|
|
|
ulist_free(refs);
|
|
ulist_free(roots);
|
|
out:
|
|
btrfs_put_delayed_seq(delayed_refs, &seq_elem);
|
|
btrfs_end_transaction(trans, fs_info->extent_root);
|
|
return ret;
|
|
}
|
|
|
|
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
iterate_extent_inodes_t *iterate, void *ctx)
|
|
{
|
|
int ret;
|
|
u64 extent_item_pos;
|
|
struct btrfs_key found_key;
|
|
|
|
ret = extent_from_logical(fs_info, logical, path,
|
|
&found_key);
|
|
btrfs_release_path(path);
|
|
if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
|
|
ret = -EINVAL;
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
extent_item_pos = logical - found_key.objectid;
|
|
ret = iterate_extent_inodes(fs_info, path, found_key.objectid,
|
|
extent_item_pos, iterate, ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path,
|
|
iterate_irefs_t *iterate, void *ctx)
|
|
{
|
|
int ret;
|
|
int slot;
|
|
u32 cur;
|
|
u32 len;
|
|
u32 name_len;
|
|
u64 parent = 0;
|
|
int found = 0;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_item *item;
|
|
struct btrfs_inode_ref *iref;
|
|
struct btrfs_key found_key;
|
|
|
|
while (1) {
|
|
ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
|
|
&found_key);
|
|
if (ret < 0)
|
|
break;
|
|
if (ret) {
|
|
ret = found ? 0 : -ENOENT;
|
|
break;
|
|
}
|
|
++found;
|
|
|
|
parent = found_key.offset;
|
|
slot = path->slots[0];
|
|
eb = path->nodes[0];
|
|
/* make sure we can use eb after releasing the path */
|
|
atomic_inc(&eb->refs);
|
|
btrfs_release_path(path);
|
|
|
|
item = btrfs_item_nr(eb, slot);
|
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
|
|
|
|
for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
|
|
name_len = btrfs_inode_ref_name_len(eb, iref);
|
|
/* path must be released before calling iterate()! */
|
|
pr_debug("following ref at offset %u for inode %llu in "
|
|
"tree %llu\n", cur,
|
|
(unsigned long long)found_key.objectid,
|
|
(unsigned long long)fs_root->objectid);
|
|
ret = iterate(parent, iref, eb, ctx);
|
|
if (ret) {
|
|
free_extent_buffer(eb);
|
|
break;
|
|
}
|
|
len = sizeof(*iref) + name_len;
|
|
iref = (struct btrfs_inode_ref *)((char *)iref + len);
|
|
}
|
|
free_extent_buffer(eb);
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* returns 0 if the path could be dumped (probably truncated)
|
|
* returns <0 in case of an error
|
|
*/
|
|
static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref,
|
|
struct extent_buffer *eb, void *ctx)
|
|
{
|
|
struct inode_fs_paths *ipath = ctx;
|
|
char *fspath;
|
|
char *fspath_min;
|
|
int i = ipath->fspath->elem_cnt;
|
|
const int s_ptr = sizeof(char *);
|
|
u32 bytes_left;
|
|
|
|
bytes_left = ipath->fspath->bytes_left > s_ptr ?
|
|
ipath->fspath->bytes_left - s_ptr : 0;
|
|
|
|
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
|
|
fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb,
|
|
inum, fspath_min, bytes_left);
|
|
if (IS_ERR(fspath))
|
|
return PTR_ERR(fspath);
|
|
|
|
if (fspath > fspath_min) {
|
|
pr_debug("path resolved: %s\n", fspath);
|
|
ipath->fspath->val[i] = (u64)(unsigned long)fspath;
|
|
++ipath->fspath->elem_cnt;
|
|
ipath->fspath->bytes_left = fspath - fspath_min;
|
|
} else {
|
|
pr_debug("missed path, not enough space. missing bytes: %lu, "
|
|
"constructed so far: %s\n",
|
|
(unsigned long)(fspath_min - fspath), fspath_min);
|
|
++ipath->fspath->elem_missed;
|
|
ipath->fspath->bytes_missing += fspath_min - fspath;
|
|
ipath->fspath->bytes_left = 0;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this dumps all file system paths to the inode into the ipath struct, provided
|
|
* is has been created large enough. each path is zero-terminated and accessed
|
|
* from ipath->fspath->val[i].
|
|
* when it returns, there are ipath->fspath->elem_cnt number of paths available
|
|
* in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
|
|
* number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
|
|
* it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
|
|
* have been needed to return all paths.
|
|
*/
|
|
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
|
|
{
|
|
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
|
|
inode_to_path, ipath);
|
|
}
|
|
|
|
/*
|
|
* allocates space to return multiple file system paths for an inode.
|
|
* total_bytes to allocate are passed, note that space usable for actual path
|
|
* information will be total_bytes - sizeof(struct inode_fs_paths).
|
|
* the returned pointer must be freed with free_ipath() in the end.
|
|
*/
|
|
struct btrfs_data_container *init_data_container(u32 total_bytes)
|
|
{
|
|
struct btrfs_data_container *data;
|
|
size_t alloc_bytes;
|
|
|
|
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
|
|
data = kmalloc(alloc_bytes, GFP_NOFS);
|
|
if (!data)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (total_bytes >= sizeof(*data)) {
|
|
data->bytes_left = total_bytes - sizeof(*data);
|
|
data->bytes_missing = 0;
|
|
} else {
|
|
data->bytes_missing = sizeof(*data) - total_bytes;
|
|
data->bytes_left = 0;
|
|
}
|
|
|
|
data->elem_cnt = 0;
|
|
data->elem_missed = 0;
|
|
|
|
return data;
|
|
}
|
|
|
|
/*
|
|
* allocates space to return multiple file system paths for an inode.
|
|
* total_bytes to allocate are passed, note that space usable for actual path
|
|
* information will be total_bytes - sizeof(struct inode_fs_paths).
|
|
* the returned pointer must be freed with free_ipath() in the end.
|
|
*/
|
|
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path)
|
|
{
|
|
struct inode_fs_paths *ifp;
|
|
struct btrfs_data_container *fspath;
|
|
|
|
fspath = init_data_container(total_bytes);
|
|
if (IS_ERR(fspath))
|
|
return (void *)fspath;
|
|
|
|
ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
|
|
if (!ifp) {
|
|
kfree(fspath);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
ifp->btrfs_path = path;
|
|
ifp->fspath = fspath;
|
|
ifp->fs_root = fs_root;
|
|
|
|
return ifp;
|
|
}
|
|
|
|
void free_ipath(struct inode_fs_paths *ipath)
|
|
{
|
|
kfree(ipath);
|
|
}
|