- 根目录:
- fs
- btrfs
- inode-item.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 "hash.h"
#include "transaction.h"
#include "print-tree.h"
static int find_name_in_backref(struct btrfs_path *path, const char *name,
int name_len, struct btrfs_inode_ref **ref_ret)
{
struct extent_buffer *leaf;
struct btrfs_inode_ref *ref;
unsigned long ptr;
unsigned long name_ptr;
u32 item_size;
u32 cur_offset = 0;
int len;
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
while (cur_offset < item_size) {
ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
len = btrfs_inode_ref_name_len(leaf, ref);
name_ptr = (unsigned long)(ref + 1);
cur_offset += len + sizeof(*ref);
if (len != name_len)
continue;
if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
*ref_ret = ref;
return 1;
}
}
return 0;
}
int btrfs_find_name_in_ext_backref(struct btrfs_path *path, u64 ref_objectid,
const char *name, int name_len,
struct btrfs_inode_extref **extref_ret)
{
struct extent_buffer *leaf;
struct btrfs_inode_extref *extref;
unsigned long ptr;
unsigned long name_ptr;
u32 item_size;
u32 cur_offset = 0;
int ref_name_len;
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
/*
* Search all extended backrefs in this item. We're only
* looking through any collisions so most of the time this is
* just going to compare against one buffer. If all is well,
* we'll return success and the inode ref object.
*/
while (cur_offset < item_size) {
extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
name_ptr = (unsigned long)(&extref->name);
ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
if (ref_name_len == name_len &&
btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
(memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) {
if (extref_ret)
*extref_ret = extref;
return 1;
}
cur_offset += ref_name_len + sizeof(*extref);
}
return 0;
}
/* Returns NULL if no extref found */
struct btrfs_inode_extref *
btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid, int ins_len,
int cow)
{
int ret;
struct btrfs_key key;
struct btrfs_inode_extref *extref;
key.objectid = inode_objectid;
key.type = BTRFS_INODE_EXTREF_KEY;
key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
if (ret < 0)
return ERR_PTR(ret);
if (ret > 0)
return NULL;
if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len, &extref))
return NULL;
return extref;
}
static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid,
u64 *index)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_extref *extref;
struct extent_buffer *leaf;
int ret;
int del_len = name_len + sizeof(*extref);
unsigned long ptr;
unsigned long item_start;
u32 item_size;
key.objectid = inode_objectid;
key.type = BTRFS_INODE_EXTREF_KEY;
key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
if (ret < 0)
goto out;
/*
* Sanity check - did we find the right item for this name?
* This should always succeed so error here will make the FS
* readonly.
*/
if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
name, name_len, &extref)) {
btrfs_std_error(root->fs_info, -ENOENT, NULL);
ret = -EROFS;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (index)
*index = btrfs_inode_extref_index(leaf, extref);
if (del_len == item_size) {
/*
* Common case only one ref in the item, remove the
* whole item.
*/
ret = btrfs_del_item(trans, root, path);
goto out;
}
ptr = (unsigned long)extref;
item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
memmove_extent_buffer(leaf, ptr, ptr + del_len,
item_size - (ptr + del_len - item_start));
btrfs_truncate_item(root, path, item_size - del_len, 1);
out:
btrfs_free_path(path);
return ret;
}
int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid, u64 *index)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_ref *ref;
struct extent_buffer *leaf;
unsigned long ptr;
unsigned long item_start;
u32 item_size;
u32 sub_item_len;
int ret;
int search_ext_refs = 0;
int del_len = name_len + sizeof(*ref);
key.objectid = inode_objectid;
key.offset = ref_objectid;
key.type = BTRFS_INODE_REF_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
ret = -ENOENT;
search_ext_refs = 1;
goto out;
} else if (ret < 0) {
goto out;
}
if (!find_name_in_backref(path, name, name_len, &ref)) {
ret = -ENOENT;
search_ext_refs = 1;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (index)
*index = btrfs_inode_ref_index(leaf, ref);
if (del_len == item_size) {
ret = btrfs_del_item(trans, root, path);
goto out;
}
ptr = (unsigned long)ref;
sub_item_len = name_len + sizeof(*ref);
item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
item_size - (ptr + sub_item_len - item_start));
btrfs_truncate_item(root, path, item_size - sub_item_len, 1);
out:
btrfs_free_path(path);
if (search_ext_refs) {
/*
* No refs were found, or we could not find the
* name in our ref array. Find and remove the extended
* inode ref then.
*/
return btrfs_del_inode_extref(trans, root, name, name_len,
inode_objectid, ref_objectid, index);
}
return ret;
}
/*
* btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
*
* The caller must have checked against BTRFS_LINK_MAX already.
*/
static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid, u64 index)
{
struct btrfs_inode_extref *extref;
int ret;
int ins_len = name_len + sizeof(*extref);
unsigned long ptr;
struct btrfs_path *path;
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_item *item;
key.objectid = inode_objectid;
key.type = BTRFS_INODE_EXTREF_KEY;
key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
if (ret == -EEXIST) {
if (btrfs_find_name_in_ext_backref(path, ref_objectid,
name, name_len, NULL))
goto out;
btrfs_extend_item(root, path, ins_len);
ret = 0;
}
if (ret < 0)
goto out;
leaf = path->nodes[0];
item = btrfs_item_nr(path->slots[0]);
ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
ptr += btrfs_item_size(leaf, item) - ins_len;
extref = (struct btrfs_inode_extref *)ptr;
btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
btrfs_set_inode_extref_index(path->nodes[0], extref, index);
btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
ptr = (unsigned long)&extref->name;
write_extent_buffer(path->nodes[0], name, ptr, name_len);
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
btrfs_free_path(path);
return ret;
}
/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid, u64 index)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_ref *ref;
unsigned long ptr;
int ret;
int ins_len = name_len + sizeof(*ref);
key.objectid = inode_objectid;
key.offset = ref_objectid;
key.type = BTRFS_INODE_REF_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
path->skip_release_on_error = 1;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
if (ret == -EEXIST) {
u32 old_size;
if (find_name_in_backref(path, name, name_len, &ref))
goto out;
old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
btrfs_extend_item(root, path, ins_len);
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
btrfs_set_inode_ref_index(path->nodes[0], ref, index);
ptr = (unsigned long)(ref + 1);
ret = 0;
} else if (ret < 0) {
if (ret == -EOVERFLOW) {
if (find_name_in_backref(path, name, name_len, &ref))
ret = -EEXIST;
else
ret = -EMLINK;
}
goto out;
} else {
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
btrfs_set_inode_ref_index(path->nodes[0], ref, index);
ptr = (unsigned long)(ref + 1);
}
write_extent_buffer(path->nodes[0], name, ptr, name_len);
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
btrfs_free_path(path);
if (ret == -EMLINK) {
struct btrfs_super_block *disk_super = root->fs_info->super_copy;
/* We ran out of space in the ref array. Need to
* add an extended ref. */
if (btrfs_super_incompat_flags(disk_super)
& BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
ret = btrfs_insert_inode_extref(trans, root, name,
name_len,
inode_objectid,
ref_objectid, index);
}
return ret;
}
int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid)
{
struct btrfs_key key;
int ret;
key.objectid = objectid;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_insert_empty_item(trans, root, path, &key,
sizeof(struct btrfs_inode_item));
return ret;
}
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path,
struct btrfs_key *location, int mod)
{
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
int ret;
int slot;
struct extent_buffer *leaf;
struct btrfs_key found_key;
ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
location->offset == (u64)-1 && path->slots[0] != 0) {
slot = path->slots[0] - 1;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid == location->objectid &&
found_key.type == location->type) {
path->slots[0]--;
return 0;
}
}
return ret;
}