b17854275c
btrfs_find_free_objectid may return a used objectid due to arithmetic underflow. This bug may happen when parameter 'root' is tree root, so it may cause serious problems when creating snapshot or sub-volume. Signed-off-by: Chris Mason <chris.mason@oracle.com>
133 lines
3.1 KiB
C
133 lines
3.1 KiB
C
/*
|
|
* Copyright (C) 2007 Oracle. All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public
|
|
* License v2 as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public
|
|
* License along with this program; if not, write to the
|
|
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
* Boston, MA 021110-1307, USA.
|
|
*/
|
|
|
|
#include "ctree.h"
|
|
#include "disk-io.h"
|
|
#include "transaction.h"
|
|
|
|
int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
|
|
{
|
|
struct btrfs_path *path;
|
|
int ret;
|
|
struct extent_buffer *l;
|
|
struct btrfs_key search_key;
|
|
struct btrfs_key found_key;
|
|
int slot;
|
|
|
|
path = btrfs_alloc_path();
|
|
BUG_ON(!path);
|
|
|
|
search_key.objectid = (u64)-1;
|
|
search_key.offset = (u64)-1;
|
|
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
|
|
if (ret < 0)
|
|
goto error;
|
|
BUG_ON(ret == 0);
|
|
if (path->slots[0] > 0) {
|
|
slot = path->slots[0] - 1;
|
|
l = path->nodes[0];
|
|
btrfs_item_key_to_cpu(l, &found_key, slot);
|
|
*objectid = found_key.objectid;
|
|
} else {
|
|
*objectid = BTRFS_FIRST_FREE_OBJECTID;
|
|
}
|
|
ret = 0;
|
|
error:
|
|
btrfs_free_path(path);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* walks the btree of allocated inodes and find a hole.
|
|
*/
|
|
int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
u64 dirid, u64 *objectid)
|
|
{
|
|
struct btrfs_path *path;
|
|
struct btrfs_key key;
|
|
int ret;
|
|
int slot = 0;
|
|
u64 last_ino = 0;
|
|
int start_found;
|
|
struct extent_buffer *l;
|
|
struct btrfs_key search_key;
|
|
u64 search_start = dirid;
|
|
|
|
path = btrfs_alloc_path();
|
|
BUG_ON(!path);
|
|
search_start = root->last_inode_alloc;
|
|
search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
|
|
search_key.objectid = search_start;
|
|
search_key.offset = 0;
|
|
|
|
btrfs_init_path(path);
|
|
start_found = 0;
|
|
ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
if (path->slots[0] > 0)
|
|
path->slots[0]--;
|
|
|
|
while (1) {
|
|
l = path->nodes[0];
|
|
slot = path->slots[0];
|
|
if (slot >= btrfs_header_nritems(l)) {
|
|
ret = btrfs_next_leaf(root, path);
|
|
if (ret == 0)
|
|
continue;
|
|
if (ret < 0)
|
|
goto error;
|
|
if (!start_found) {
|
|
*objectid = search_start;
|
|
start_found = 1;
|
|
goto found;
|
|
}
|
|
*objectid = last_ino > search_start ?
|
|
last_ino : search_start;
|
|
goto found;
|
|
}
|
|
btrfs_item_key_to_cpu(l, &key, slot);
|
|
if (key.objectid >= search_start) {
|
|
if (start_found) {
|
|
if (last_ino < search_start)
|
|
last_ino = search_start;
|
|
if (key.objectid > last_ino) {
|
|
*objectid = last_ino;
|
|
goto found;
|
|
}
|
|
}
|
|
}
|
|
start_found = 1;
|
|
last_ino = key.objectid + 1;
|
|
path->slots[0]++;
|
|
}
|
|
// FIXME -ENOSPC
|
|
found:
|
|
root->last_inode_alloc = *objectid;
|
|
btrfs_release_path(root, path);
|
|
btrfs_free_path(path);
|
|
BUG_ON(*objectid < search_start);
|
|
return 0;
|
|
error:
|
|
btrfs_release_path(root, path);
|
|
btrfs_free_path(path);
|
|
return ret;
|
|
}
|