/*
* 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 "transaction.h"
#include "disk-io.h"
#include "print-tree.h"
/*
* search forward for a root, starting with objectid 'search_start'
* if a root key is found, the objectid we find is filled into 'found_objectid'
* and 0 is returned. < 0 is returned on error, 1 if there is nothing
* left in the tree.
*/
int btrfs_search_root(struct btrfs_root *root, u64 search_start,
u64 *found_objectid)
{
struct btrfs_path *path;
struct btrfs_key search_key;
int ret;
root = root->fs_info->tree_root;
search_key.objectid = search_start;
search_key.type = (u8)-1;
search_key.offset = (u64)-1;
path = btrfs_alloc_path();
BUG_ON(!path);
again:
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
if (ret < 0)
goto out;
if (ret == 0) {
ret = 1;
goto out;
}
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret)
goto out;
}
btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
search_key.offset++;
btrfs_release_path(root, path);
goto again;
}
ret = 0;
*found_objectid = search_key.objectid;
out:
btrfs_free_path(path);
return ret;
}
/*
* lookup the root with the highest offset for a given objectid. The key we do
* find is copied into 'key'. If we find something return 0, otherwise 1, < 0
* on error.
*/
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
struct btrfs_root_item *item, struct btrfs_key *key)
{
struct btrfs_path *path;
struct btrfs_key search_key;
struct btrfs_key found_key;
struct extent_buffer *l;
int ret;
int slot;
search_key.objectid = objectid;
search_key.type = BTRFS_ROOT_ITEM_KEY;
search_key.offset = (u64)-1;
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0);
l = path->nodes[0];
BUG_ON(path->slots[0] == 0);
slot = path->slots[0] - 1;
btrfs_item_key_to_cpu(l, &found_key, slot);
if (found_key.objectid != objectid) {
ret = 1;
goto out;
}
read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
sizeof(*item));
memcpy(key, &found_key, sizeof(found_key));
ret = 0;
out:
btrfs_free_path(path);
return ret;
}
/*
* 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_path *path;
struct extent_buffer *l;
int ret;
int slot;
unsigned long ptr;
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_search_slot(trans, root, key, path, 0, 1);
if (ret < 0)
goto out;
if (ret != 0) {
btrfs_print_leaf(root, path->nodes[0]);
printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
(unsigned long long)key->objectid, key->type,
(unsigned long long)key->offset);
BUG_ON(1);
}
l = path->nodes[0];
slot = path->slots[0];
ptr = btrfs_item_ptr_offset(l, slot);
write_extent_buffer(l, item, ptr, sizeof(*item));
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_root_item
*item)
{
int ret;
ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
return ret;
}
/*
* at mount time we want to find all the old transaction snapshots that were in
* the process of being deleted if we crashed. This is any root item with an
* offset lower than the latest root. They need to be queued for deletion to
* finish what was happening when we crashed.
*/
int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
struct btrfs_root *latest)
{
struct btrfs_root *dead_root;
struct btrfs_item *item;
struct btrfs_root_item *ri;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_path *path;
int ret;
u32 nritems;
struct extent_buffer *leaf;
int slot;
key.objectid = objectid;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
key.offset = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
again:
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto err;
while (1) {
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
slot = path->slots[0];
if (slot >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret)
break;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
slot = path->slots[0];
}
item = btrfs_item_nr(leaf, slot);
btrfs_item_key_to_cpu(leaf, &key, slot);
if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
goto next;
if (key.objectid < objectid)
goto next;
if (key.objectid > objectid)
break;
ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
if (btrfs_disk_root_refs(leaf, ri) != 0)
goto next;
memcpy(&found_key, &key, sizeof(key));
key.offset++;
btrfs_release_path(root, path);
dead_root =
btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
&found_key);
if (IS_ERR(dead_root)) {
ret = PTR_ERR(dead_root);
goto err;
}
if (objectid == BTRFS_TREE_RELOC_OBJECTID)
ret = btrfs_add_dead_reloc_root(dead_root);
else
ret = btrfs_add_dead_root(dead_root, latest);
if (ret)
goto err;
goto again;
next:
slot++;
path->slots[0]++;
}
ret = 0;
err:
btrfs_free_path(path);
return ret;
}
/* drop the root item for 'key' from 'root' */
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_key *key)
{
struct btrfs_path *path;
int ret;
u32 refs;
struct btrfs_root_item *ri;
struct extent_buffer *leaf;
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_search_slot(trans, root, key, path, -1, 1);
if (ret < 0)
goto out;
BUG_ON(ret != 0);
leaf = path->nodes[0];
ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
refs = btrfs_disk_root_refs(leaf, ri);
BUG_ON(refs != 0);
ret = btrfs_del_item(trans, root, path);
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
#if 0 /* this will get used when snapshot deletion is implemented */
int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *tree_root,
u64 root_id, u8 type, u64 ref_id)
{
struct btrfs_key key;
int ret;
struct btrfs_path *path;
path = btrfs_alloc_path();
key.objectid = root_id;
key.type = type;
key.offset = ref_id;
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
BUG_ON(ret);
ret = btrfs_del_item(trans, tree_root, path);
BUG_ON(ret);
btrfs_free_path(path);
return ret;
}
#endif
int btrfs_find_root_ref(struct btrfs_root *tree_root,
struct btrfs_path *path,
u64 root_id, u64 ref_id)
{
struct btrfs_key key;
int ret;
key.objectid = root_id;
key.type = BTRFS_ROOT_REF_KEY;
key.offset = ref_id;
ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
return ret;
}
/*
* add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
* or BTRFS_ROOT_BACKREF_KEY.
*
* The dirid, sequence, name and name_len refer to the directory entry
* that is referencing the root.
*
* For a forward ref, the root_id is the id of the tree referencing
* the root and ref_id is the id of the subvol or snapshot.
*
* For a back ref the root_id is the id of the subvol or snapshot and
* ref_id is the id of the tree referencing it.
*/
int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *tree_root,
u64 root_id, u8 type, u64 ref_id,
u64 dirid, u64 sequence,
const char *name, int name_len)
{
struct btrfs_key key;
int ret;
struct btrfs_path *path;
struct btrfs_root_ref *ref;
struct extent_buffer *leaf;
unsigned long ptr;
path = btrfs_alloc_path();
key.objectid = root_id;
key.type = type;
key.offset = ref_id;
ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
sizeof(*ref) + name_len);
BUG_ON(ret);
leaf = path->nodes[0];
ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
btrfs_set_root_ref_dirid(leaf, ref, dirid);
btrfs_set_root_ref_sequence(leaf, ref, sequence);
btrfs_set_root_ref_name_len(leaf, ref, name_len);
ptr = (unsigned long)(ref + 1);
write_extent_buffer(leaf, name, ptr, name_len);
btrfs_mark_buffer_dirty(leaf);
btrfs_free_path(path);
return ret;
}
