223 lines
5.5 KiB
C
223 lines
5.5 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 "ctree.h"
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#include "transaction.h"
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#include "disk-io.h"
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#include "kernel-shared/print-tree.h"
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int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
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struct btrfs_root_item *item, struct btrfs_key *key)
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{
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struct btrfs_path *path;
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struct btrfs_key search_key;
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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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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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search_key.objectid = objectid;
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search_key.type = BTRFS_ROOT_ITEM_KEY;
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search_key.offset = (u64)-1;
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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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goto out;
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if (path->slots[0] == 0) {
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ret = -ENOENT;
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goto out;
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}
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BUG_ON(ret == 0);
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l = path->nodes[0];
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slot = path->slots[0] - 1;
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btrfs_item_key_to_cpu(l, &found_key, slot);
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if (found_key.type != BTRFS_ROOT_ITEM_KEY ||
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found_key.objectid != objectid) {
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ret = -ENOENT;
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goto out;
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}
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read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
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sizeof(*item));
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memcpy(key, &found_key, sizeof(found_key));
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ret = 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_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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u32 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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goto out;
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BUG_ON(ret != 0);
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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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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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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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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
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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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int ret;
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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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ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
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return ret;
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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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if (ret != 0) {
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ret = -ENOENT;
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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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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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* 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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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, u8 type, u64 ref_id,
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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 = type;
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key.offset = ref_id;
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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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BUG_ON(ret);
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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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btrfs_free_path(path);
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return ret;
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}
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