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/*
* 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 <linux/err.h>
#include <linux/uuid.h>
#include "ctree.h"
#include "transaction.h"
#include "disk-io.h"
#include "print-tree.h"
/*
* Read a root item from the tree. In case we detect a root item smaller then
* sizeof(root_item), we know it's an old version of the root structure and
* initialize all new fields to zero. The same happens if we detect mismatching
* generation numbers as then we know the root was once mounted with an older
* kernel that was not aware of the root item structure change.
*/
static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
struct btrfs_root_item *item)
{
uuid_le uuid;
int len;
int need_reset = 0;
len = btrfs_item_size_nr(eb, slot);
read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
min_t(int, len, (int)sizeof(*item)));
if (len < sizeof(*item))
need_reset = 1;
if (!need_reset && btrfs_root_generation(item)
!= btrfs_root_generation_v2(item)) {
if (btrfs_root_generation_v2(item) != 0) {
btrfs_warn(eb->fs_info,
"mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");
}
need_reset = 1;
}
if (need_reset) {
memset(&item->generation_v2, 0,
sizeof(*item) - offsetof(struct btrfs_root_item,
generation_v2));
uuid_le_gen(&uuid);
memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
}
}
/*
* btrfs_find_root - lookup the root by the key.
* root: the root of the root tree
* search_key: the key to search
* path: the path we search
* root_item: the root item of the tree we look for
* root_key: the root key of the tree we look for
*
* If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
* of the search key, just lookup the root with the highest offset for a
* given objectid.
*
* If we find something return 0, otherwise > 0, < 0 on error.
*/
int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key,
struct btrfs_path *path, struct btrfs_root_item *root_item,
struct btrfs_key *root_key)
{
struct btrfs_key found_key;
struct extent_buffer *l;
int ret;
int slot;
ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
if (ret < 0)
return ret;
if (search_key->offset != -1ULL) { /* the search key is exact */
if (ret > 0)
goto out;
} else {
BUG_ON(ret == 0); /* Logical error */
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
ret = 0;
}
l = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(l, &found_key, slot);
if (found_key.objectid != search_key->objectid ||
found_key.type != BTRFS_ROOT_ITEM_KEY) {
ret = 1;
goto out;
}
if (root_item)
btrfs_read_root_item(l, slot, root_item);
if (root_key)
memcpy(root_key, &found_key, sizeof(found_key));
out:
btrfs_release_path(path);
return ret;
}
void btrfs_set_root_node(struct btrfs_root_item *item,
struct extent_buffer *node)
{
btrfs_set_root_bytenr(item, node->start);
btrfs_set_root_level(item, btrfs_header_level(node));
btrfs_set_root_generation(item, btrfs_header_generation(node));
}
/*
* copy the data in 'item' into the btree
*/
int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_root_item
*item)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct extent_buffer *l;
int ret;
int slot;
unsigned long ptr;
u32 old_len;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(trans, root, key, path, 0, 1);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
if (ret != 0) {
btrfs_print_leaf(path->nodes[0]);
btrfs_crit(fs_info, "unable to update root key %llu %u %llu",
key->objectid, key->type, key->offset);
BUG_ON(1);
}
l = path->nodes[0];
slot = path->slots[0];
ptr = btrfs_item_ptr_offset(l, slot);
old_len = btrfs_item_size_nr(l, slot);
/*
* If this is the first time we update the root item which originated
* from an older kernel, we need to enlarge the item size to make room
* for the added fields.
*/
if (old_len < sizeof(*item)) {
btrfs_release_path(path);
ret = btrfs_search_slot(trans, root, key, path,
-1, 1);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
ret = btrfs_del_item(trans, root, path);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
ret = btrfs_insert_empty_item(trans, root, path,
key, sizeof(*item));
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
l = path->nodes[0];
slot = path->slots[0];
ptr = btrfs_item_ptr_offset(l, slot);
}
/*
* Update generation_v2 so at the next mount we know the new root
* fields are valid.
*/
btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
write_extent_buffer(l, item, ptr, sizeof(*item));
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
btrfs_free_path(path);
return ret;
}
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
const struct btrfs_key *key, struct btrfs_root_item *item)
{
/*
* Make sure generation v1 and v2 match. See update_root for details.
*/
btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
return btrfs_insert_item(trans, root, key, item, sizeof(*item));
}
int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
{
struct btrfs_root *tree_root = fs_info->tree_root;
struct extent_buffer *leaf;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key root_key;
struct btrfs_root *root;
int err = 0;
int ret;
bool can_recover = true;
if (sb_rdonly(fs_info->sb))
can_recover = false;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = BTRFS_ORPHAN_OBJECTID;
key.type = BTRFS_ORPHAN_ITEM_KEY;
key.offset = 0;
root_key.type
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