btrfs-progs/kernel-shared/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 "kerncompat.h"
#include <sys/stat.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include "kernel-shared/ctree.h"
#include "kernel-shared/transaction.h"
#include "kernel-shared/disk-io.h"
#include "common/messages.h"
#include "common/internal.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_item(NULL, root, path, dir, index,
name, namelen, 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, int ignore_existed)
{
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 && !(ignore_existed && ret == -EEXIST))
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 && !(ignore_existed && ret == -EEXIST))
goto out;
/* do not update nlinks if existed */
if (!ret) {
/* 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, 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_item(NULL, root, path, parent_ino,
index, name, namelen, 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_item(trans, root, path,
parent_ino, index, 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)
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;
}
/*
* Change inode flags to given value
*/
int btrfs_change_inode_flags(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 ino, u64 flags)
{
struct btrfs_inode_item *item;
struct btrfs_path *path;
struct btrfs_key key;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret > 0) {
ret = -ENOENT;
goto out;
}
if (ret < 0)
goto out;
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
btrfs_set_inode_flags(path->nodes[0], item, flags);
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
btrfs_free_path(path);
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_ftype(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, 0);
if (ret)
goto out;
out:
btrfs_free_path(path);
if (ret == 0 && ino)
*ino = ret_ino;
return ret;
}
struct btrfs_root *btrfs_mksubvol(struct btrfs_root *root,
const char *base, u64 root_objectid,
bool convert)
{
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *new_root = NULL;
struct btrfs_path path = { 0 };
struct btrfs_inode_item *inode_item;
struct extent_buffer *leaf;
struct btrfs_key key;
u64 dirid = btrfs_root_dirid(&root->root_item);
u64 index = 2;
char buf[BTRFS_NAME_LEN + 1]; /* for snprintf null */
int len;
int i;
int ret;
len = strlen(base);
if (len == 0 || len > BTRFS_NAME_LEN)
return NULL;
key.objectid = dirid;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
if (ret <= 0) {
error("search for DIR_INDEX dirid %llu failed: %d",
(unsigned long long)dirid, ret);
goto fail;
}
if (path.slots[0] > 0) {
path.slots[0]--;
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
if (key.objectid == dirid && key.type == BTRFS_DIR_INDEX_KEY)
index = key.offset + 1;
}
btrfs_release_path(&path);
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
errno = -ret;
error_msg(ERROR_MSG_START_TRANS, "%m");
goto fail;
}
key.objectid = dirid;
key.offset = 0;
key.type = BTRFS_INODE_ITEM_KEY;
ret = btrfs_lookup_inode(trans, root, &path, &key, 1);
if (ret) {
error("search for INODE_ITEM %llu failed: %d",
(unsigned long long)dirid, ret);
goto fail;
}
leaf = path.nodes[0];
inode_item = btrfs_item_ptr(leaf, path.slots[0],
struct btrfs_inode_item);
key.objectid = root_objectid;
key.offset = (u64)-1;
key.type = BTRFS_ROOT_ITEM_KEY;
memcpy(buf, base, len);
if (convert) {
for (i = 0; i < 1024; i++) {
ret = btrfs_insert_dir_item(trans, root, buf, len,
dirid, &key, BTRFS_FT_DIR, index);
if (ret != -EEXIST)
break;
len = snprintf(buf, ARRAY_SIZE(buf), "%s%d", base, i);
if (len < 1 || len > BTRFS_NAME_LEN) {
ret = -EINVAL;
break;
}
}
} else {
ret = btrfs_insert_dir_item(trans, root, buf, len, dirid, &key,
BTRFS_FT_DIR, index);
}
if (ret)
goto fail;
btrfs_set_inode_size(leaf, inode_item, len * 2 +
btrfs_inode_size(leaf, inode_item));
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(&path);
/* add the backref first */
ret = btrfs_add_root_ref(trans, tree_root, root_objectid,
BTRFS_ROOT_BACKREF_KEY,
root->root_key.objectid,
dirid, index, buf, len);
if (ret) {
error("unable to add root backref for %llu: %d",
root->root_key.objectid, ret);
goto fail;
}
/* now add the forward ref */
ret = btrfs_add_root_ref(trans, tree_root, root->root_key.objectid,
BTRFS_ROOT_REF_KEY, root_objectid,
dirid, index, buf, len);
if (ret) {
error("unable to add root ref for %llu: %d",
root->root_key.objectid, ret);
goto fail;
}
ret = btrfs_commit_transaction(trans, root);
if (ret) {
errno = -ret;
error_msg(ERROR_MSG_COMMIT_TRANS, "%m");
goto fail;
}
new_root = btrfs_read_fs_root(fs_info, &key);
if (IS_ERR(new_root)) {
error("unable to fs read root: %lu", PTR_ERR(new_root));
new_root = NULL;
}
fail:
return new_root;
}
/*
* Walk the tree 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();
if (!path)
return -ENOMEM;
search_start = root->last_inode_alloc;
search_start = max((unsigned long long)search_start,
BTRFS_FIRST_FREE_OBJECTID);
search_key.objectid = search_start;
search_key.offset = 0;
search_key.type = 0;
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_free_path(path);
BUG_ON(*objectid < search_start);
return 0;
error:
btrfs_free_path(path);
return ret;
}