btrfs-progs/inode.c

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/*
* Copyright (C) 2014 Fujitsu. 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.
*/
/*
* Unlike inode.c in kernel, which can use most of the kernel infrastructure
* like inode/dentry things, in user-land, we can only use inode number to
* do directly operation on extent buffer, which may cause extra searching,
* but should not be a huge problem since progs is less performance sensitive.
*/
#include <sys/stat.h>
#include "ctree.h"
#include "transaction.h"
#include "disk-io.h"
#include "time.h"
/*
* Find a free inode index for later btrfs_add_link().
* Currently just search from the largest dir_index and +1.
*/
static int btrfs_find_free_dir_index(struct btrfs_root *root, u64 dir_ino,
u64 *ret_ino)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
u64 ret_val = 2;
int ret = 0;
if (!ret_ino)
return 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = dir_ino;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
ret = 0;
if (path->slots[0] == 0) {
ret = btrfs_prev_leaf(root, path);
if (ret < 0)
goto out;
if (ret > 0) {
/*
* This shouldn't happen since there must be a leaf
* containing the DIR_ITEM.
* Can only happen when the previous leaf is corrupted.
*/
ret = -EIO;
goto out;
}
} else {
path->slots[0]--;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
if (found_key.objectid != dir_ino ||
found_key.type != BTRFS_DIR_INDEX_KEY)
goto out;
ret_val = found_key.offset + 1;
out:
btrfs_free_path(path);
if (ret == 0)
*ret_ino = ret_val;
return ret;
}
/* Check the dir_item/index conflicts before insert */
int check_dir_conflict(struct btrfs_root *root, char *name, int namelen,
u64 dir, u64 index)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_item *inode_item;
struct btrfs_dir_item *dir_item;
int ret = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/* Given dir exists? */
key.objectid = dir;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0) {
ret = -ENOENT;
goto out;
}
/* Is it a dir? */
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
if (!(btrfs_inode_mode(path->nodes[0], inode_item) & S_IFDIR)) {
ret = -ENOTDIR;
goto out;
}
btrfs_release_path(path);
/* Name conflicting? */
dir_item = btrfs_lookup_dir_item(NULL, root, path, dir, name,
namelen, 0);
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (dir_item) {
ret = -EEXIST;
goto out;
}
btrfs_release_path(path);
/* Index conflicting? */
dir_item = btrfs_lookup_dir_index(NULL, root, path, dir, name,
namelen, index, 0);
if (IS_ERR(dir_item) && PTR_ERR(dir_item) == -ENOENT)
dir_item = NULL;
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (dir_item) {
ret = -EEXIST;
goto out;
}
out:
btrfs_free_path(path);
return ret;
}
/*
* Add dir_item/index for 'parent_ino' if add_backref is true, also insert a
* backref from the ino to parent dir and update the nlink(Kernel version does
* not do this thing)
*
* Currently only supports adding link from an inode to another inode.
*/
int btrfs_add_link(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 ino, u64 parent_ino, char *name, int namelen,
u8 type, u64 *index, int add_backref)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_item *inode_item;
u32 nlink;
u64 inode_size;
u64 ret_index = 0;
int ret = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (index && *index) {
ret_index = *index;
} else {
ret = btrfs_find_free_dir_index(root, parent_ino, &ret_index);
if (ret < 0)
goto out;
}
ret = check_dir_conflict(root, name, namelen, parent_ino, ret_index);
if (ret < 0)
goto out;
/* Add inode ref */
if (add_backref) {
ret = btrfs_insert_inode_ref(trans, root, name, namelen,
ino, parent_ino, ret_index);
if (ret < 0)
goto out;
/* Update nlinks for the inode */
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto out;
}
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
nlink = btrfs_inode_nlink(path->nodes[0], inode_item);
nlink++;
btrfs_set_inode_nlink(path->nodes[0], inode_item, nlink);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
}
/* Add dir_item and dir_index */
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_insert_dir_item(trans, root, name, namelen, parent_ino,
&key, type, ret_index);
if (ret < 0)
goto out;
/* Update inode size of the parent inode */
key.objectid = parent_ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
if (ret)
goto out;
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
inode_size = btrfs_inode_size(path->nodes[0], inode_item);
inode_size += namelen * 2;
btrfs_set_inode_size(path->nodes[0], inode_item, inode_size);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
out:
btrfs_free_path(path);
if (ret == 0 && index)
*index = ret_index;
return ret;
}
int btrfs_add_orphan_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u64 ino)
{
struct btrfs_key key;
key.objectid = BTRFS_ORPHAN_OBJECTID;
key.type = BTRFS_ORPHAN_ITEM_KEY;
key.offset = ino;
return btrfs_insert_empty_item(trans, root, path, &key, 0);
}
/*
* Unlink an inode, which will remove its backref and corresponding dir_index/
* dir_item if any of them exists.
*
* If an inode's nlink is reduced to 0 and 'add_orphan' is true, it will be
* added to orphan inode and waiting to be deleted by next kernel mount.
*/
int btrfs_unlink(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 ino, u64 parent_ino, u64 index, const char *name,
int namelen, int add_orphan)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_item *inode_item;
struct btrfs_inode_ref *inode_ref;
struct btrfs_dir_item *dir_item;
u64 inode_size;
u32 nlinks;
int del_inode_ref = 0;
int del_dir_item = 0;
int del_dir_index = 0;
int ret = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/* check the ref and backref exists */
inode_ref = btrfs_lookup_inode_ref(trans, root, path, name, namelen,
ino, parent_ino, index, 0);
if (IS_ERR(inode_ref)) {
ret = PTR_ERR(inode_ref);
goto out;
}
if (inode_ref)
del_inode_ref = 1;
btrfs_release_path(path);
dir_item = btrfs_lookup_dir_item(NULL, root, path, parent_ino,
name, namelen, 0);
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (dir_item)
del_dir_item = 1;
btrfs_release_path(path);
dir_item = btrfs_lookup_dir_index(NULL, root, path, parent_ino,
name, namelen, index, 0);
/*
* Since lookup_dir_index() will return -ENOENT when not found,
* we need to do extra check.
*/
if (IS_ERR(dir_item) && PTR_ERR(dir_item) == -ENOENT)
dir_item = NULL;
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (dir_item)
del_dir_index = 1;
btrfs_release_path(path);
if (!del_inode_ref && !del_dir_item && !del_dir_index) {
/* All not found, shouldn't happen */
ret = -ENOENT;
goto out;
}
if (del_inode_ref) {
/* Only decrease nlink when deleting inode_ref */
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto out;
}
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
nlinks = btrfs_inode_nlink(path->nodes[0], inode_item);
if (nlinks > 0)
nlinks--;
btrfs_set_inode_nlink(path->nodes[0], inode_item, nlinks);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
/* For nlinks == 0, add it to orphan list if needed */
if (nlinks == 0 && add_orphan) {
ret = btrfs_add_orphan_item(trans, root, path, ino);
if (ret < 0)
goto out;
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
}
ret = btrfs_del_inode_ref(trans, root, name, namelen, ino,
parent_ino, &index);
if (ret < 0)
goto out;
}
if (del_dir_index) {
dir_item = btrfs_lookup_dir_index(trans, root, path,
parent_ino, name, namelen,
index, -1);
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (!dir_item) {
ret = -ENOENT;
goto out;
}
ret = btrfs_delete_one_dir_name(trans, root, path, dir_item);
if (ret)
goto out;
btrfs_release_path(path);
/* Update inode size of the parent inode */
key.objectid = parent_ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
if (ret)
goto out;
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
inode_size = btrfs_inode_size(path->nodes[0], inode_item);
if (inode_size >= namelen)
inode_size -= namelen;
btrfs_set_inode_size(path->nodes[0], inode_item, inode_size);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
}
if (del_dir_item) {
dir_item = btrfs_lookup_dir_item(trans, root, path, parent_ino,
name, namelen, -1);
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (!dir_item) {
ret = -ENOENT;
goto out;
}
ret = btrfs_delete_one_dir_name(trans, root, path, dir_item);
if (ret < 0)
goto out;
btrfs_release_path(path);
/* Update inode size of the parent inode */
key.objectid = parent_ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
if (ret)
goto out;
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
inode_size = btrfs_inode_size(path->nodes[0], inode_item);
if (inode_size >= namelen)
inode_size -= namelen;
btrfs_set_inode_size(path->nodes[0], inode_item, inode_size);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
}
out:
btrfs_free_path(path);
return ret;
}
/* Fill inode item with 'mode'. Uid/gid to root/root */
static void fill_inode_item(struct btrfs_trans_handle *trans,
struct btrfs_inode_item *inode_item,
u32 mode, u32 nlink)
{
time_t now = time(NULL);
btrfs_set_stack_inode_generation(inode_item, trans->transid);
btrfs_set_stack_inode_uid(inode_item, 0);
btrfs_set_stack_inode_gid(inode_item, 0);
btrfs_set_stack_inode_size(inode_item, 0);
btrfs_set_stack_inode_mode(inode_item, mode);
btrfs_set_stack_inode_nlink(inode_item, nlink);
btrfs_set_stack_timespec_sec(&inode_item->atime, now);
btrfs_set_stack_timespec_nsec(&inode_item->atime, 0);
btrfs_set_stack_timespec_sec(&inode_item->mtime, now);
btrfs_set_stack_timespec_nsec(&inode_item->mtime, 0);
btrfs_set_stack_timespec_sec(&inode_item->ctime, now);
btrfs_set_stack_timespec_nsec(&inode_item->ctime, 0);
}
/*
* Unlike kernel btrfs_new_inode(), we only create the INODE_ITEM, without
* its backref.
* The backref is added by btrfs_add_link().
*/
int btrfs_new_inode(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 ino, u32 mode)
{
struct btrfs_inode_item inode_item = {0};
int ret = 0;
fill_inode_item(trans, &inode_item, mode, 0);
ret = btrfs_insert_inode(trans, root, ino, &inode_item);
return ret;
}
/*
* Make a dir under the parent inode 'parent_ino' with 'name'
* and 'mode', The owner will be root/root.
*/
int btrfs_mkdir(struct btrfs_trans_handle *trans, struct btrfs_root *root,
char *name, int namelen, u64 parent_ino, u64 *ino, int mode)
{
struct btrfs_dir_item *dir_item;
struct btrfs_path *path;
u64 ret_ino = 0;
int ret = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (ino && *ino)
ret_ino = *ino;
dir_item = btrfs_lookup_dir_item(NULL, root, path, parent_ino,
name, namelen, 0);
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
goto out;
}
if (dir_item) {
struct btrfs_key found_key;
/*
* Already have conflicting name, check if it is a dir.
* Either way, no need to continue.
*/
btrfs_dir_item_key_to_cpu(path->nodes[0], dir_item, &found_key);
ret_ino = found_key.objectid;
if (btrfs_dir_type(path->nodes[0], dir_item) != BTRFS_FT_DIR)
ret = -EEXIST;
goto out;
}
if (!ret_ino)
/*
* This is *UNSAFE* if some leaf is corrupted,
* only used as a fallback method. Caller should either
* ensure the fs is OK or pass ino with unused inode number.
*/
ret = btrfs_find_free_objectid(NULL, root, parent_ino,
&ret_ino);
if (ret)
goto out;
ret = btrfs_new_inode(trans, root, ret_ino, mode | S_IFDIR);
if (ret)
goto out;
ret = btrfs_add_link(trans, root, ret_ino, parent_ino, name, namelen,
BTRFS_FT_DIR, NULL, 1);
if (ret)
goto out;
out:
btrfs_free_path(path);
if (ret == 0 && ino)
*ino = ret_ino;
return ret;
}