btrfs-progs/common/send-utils.c
David Sterba 0fc4bb4d91 btrfs-progs: remove unused subvol_uuid_search_add
After removal of the fallback uuid search code the helper is unused in
the internal code.

Signed-off-by: David Sterba <dsterba@suse.com>
2021-10-08 20:47:04 +02:00

350 lines
9.1 KiB
C

/*
* Copyright (C) 2012 Alexander Block. 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 <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <uuid/uuid.h>
#include <limits.h>
#include <errno.h>
#include "kernel-shared/ctree.h"
#include "common/send-utils.h"
#include "common/messages.h"
#include "common/utils.h"
#include "ioctl.h"
static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
u64 subvol_id);
static int btrfs_get_root_id_by_sub_path(int mnt_fd, const char *sub_path,
u64 *root_id)
{
int ret;
int subvol_fd;
subvol_fd = openat(mnt_fd, sub_path, O_RDONLY);
if (subvol_fd < 0) {
ret = -errno;
fprintf(stderr, "ERROR: open %s failed: %m\n", sub_path);
return ret;
}
ret = lookup_path_rootid(subvol_fd, root_id);
if (ret) {
errno = -ret;
error("cannot resolve rootid for path: %m");
}
close(subvol_fd);
return ret;
}
static int btrfs_read_root_item_raw(int mnt_fd, u64 root_id, size_t buf_len,
u32 *read_len, void *buf)
{
int ret;
struct btrfs_ioctl_search_args args;
struct btrfs_ioctl_search_key *sk = &args.key;
struct btrfs_ioctl_search_header *sh;
unsigned long off = 0;
int found = 0;
int i;
*read_len = 0;
memset(&args, 0, sizeof(args));
sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
/*
* there may be more than one ROOT_ITEM key if there are
* snapshots pending deletion, we have to loop through
* them.
*/
sk->min_objectid = root_id;
sk->max_objectid = root_id;
sk->max_type = BTRFS_ROOT_ITEM_KEY;
sk->min_type = BTRFS_ROOT_ITEM_KEY;
sk->max_offset = (u64)-1;
sk->max_transid = (u64)-1;
sk->nr_items = 4096;
while (1) {
ret = ioctl(mnt_fd, BTRFS_IOC_TREE_SEARCH, &args);
if (ret < 0) {
fprintf(stderr,
"ERROR: can't perform the search - %m\n");
return 0;
}
/* the ioctl returns the number of item it found in nr_items */
if (sk->nr_items == 0)
break;
off = 0;
for (i = 0; i < sk->nr_items; i++) {
struct btrfs_root_item *item;
sh = (struct btrfs_ioctl_search_header *)(args.buf +
off);
off += sizeof(*sh);
item = (struct btrfs_root_item *)(args.buf + off);
off += btrfs_search_header_len(sh);
sk->min_objectid = btrfs_search_header_objectid(sh);
sk->min_type = btrfs_search_header_type(sh);
sk->min_offset = btrfs_search_header_offset(sh);
if (btrfs_search_header_objectid(sh) > root_id)
break;
if (btrfs_search_header_objectid(sh) == root_id &&
btrfs_search_header_type(sh) == BTRFS_ROOT_ITEM_KEY) {
if (btrfs_search_header_len(sh) > buf_len) {
/* btrfs-progs is too old for kernel */
fprintf(stderr,
"ERROR: buf for read_root_item_raw() is too small, get newer btrfs tools!\n");
return -EOVERFLOW;
}
memcpy(buf, item, btrfs_search_header_len(sh));
*read_len = btrfs_search_header_len(sh);
found = 1;
}
}
if (sk->min_offset < (u64)-1)
sk->min_offset++;
else
break;
if (sk->min_type != BTRFS_ROOT_ITEM_KEY ||
sk->min_objectid != root_id)
break;
}
return found ? 0 : -ENOENT;
}
/*
* 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 int btrfs_read_root_item(int mnt_fd, u64 root_id,
struct btrfs_root_item *item)
{
int ret;
u32 read_len;
ret = btrfs_read_root_item_raw(mnt_fd, root_id, sizeof(*item),
&read_len, item);
if (ret)
return ret;
if (read_len < sizeof(*item) ||
btrfs_root_generation(item) != btrfs_root_generation_v2(item)) {
/*
* Workaround for gcc9 that warns that memset over
* generation_v2 overflows, which is what we want but would
* be otherwise a bug
*
* The below is &item->generation_v2
*/
char *start = (char *)item + offsetof(struct btrfs_root_item,
generation_v2);
memset(start, 0,
sizeof(*item) - offsetof(struct btrfs_root_item,
generation_v2));
}
return 0;
}
int btrfs_subvolid_resolve(int fd, char *path, size_t path_len, u64 subvol_id)
{
if (path_len < 1)
return -EOVERFLOW;
path[0] = '\0';
path_len--;
path[path_len] = '\0';
return btrfs_subvolid_resolve_sub(fd, path, &path_len, subvol_id);
}
static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
u64 subvol_id)
{
int ret;
struct btrfs_ioctl_search_args search_arg;
struct btrfs_ioctl_ino_lookup_args ino_lookup_arg;
struct btrfs_ioctl_search_header *search_header;
struct btrfs_root_ref *backref_item;
if (subvol_id == BTRFS_FS_TREE_OBJECTID) {
if (*path_len < 1)
return -EOVERFLOW;
*path = '\0';
(*path_len)--;
return 0;
}
memset(&search_arg, 0, sizeof(search_arg));
search_arg.key.tree_id = BTRFS_ROOT_TREE_OBJECTID;
search_arg.key.min_objectid = subvol_id;
search_arg.key.max_objectid = subvol_id;
search_arg.key.min_type = BTRFS_ROOT_BACKREF_KEY;
search_arg.key.max_type = BTRFS_ROOT_BACKREF_KEY;
search_arg.key.max_offset = (u64)-1;
search_arg.key.max_transid = (u64)-1;
search_arg.key.nr_items = 1;
ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search_arg);
if (ret < 0) {
fprintf(stderr,
"ioctl(BTRFS_IOC_TREE_SEARCH, subvol_id %llu) ret=%d, error: %m\n",
(unsigned long long)subvol_id, ret);
return ret;
}
if (search_arg.key.nr_items < 1) {
fprintf(stderr,
"failed to lookup subvol_id %llu!\n",
(unsigned long long)subvol_id);
return -ENOENT;
}
search_header = (struct btrfs_ioctl_search_header *)search_arg.buf;
backref_item = (struct btrfs_root_ref *)(search_header + 1);
if (btrfs_search_header_offset(search_header)
!= BTRFS_FS_TREE_OBJECTID) {
int sub_ret;
sub_ret = btrfs_subvolid_resolve_sub(fd, path, path_len,
btrfs_search_header_offset(search_header));
if (sub_ret)
return sub_ret;
if (*path_len < 1)
return -EOVERFLOW;
strcat(path, "/");
(*path_len)--;
}
if (btrfs_stack_root_ref_dirid(backref_item) !=
BTRFS_FIRST_FREE_OBJECTID) {
int len;
memset(&ino_lookup_arg, 0, sizeof(ino_lookup_arg));
ino_lookup_arg.treeid =
btrfs_search_header_offset(search_header);
ino_lookup_arg.objectid =
btrfs_stack_root_ref_dirid(backref_item);
ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &ino_lookup_arg);
if (ret < 0) {
fprintf(stderr,
"ioctl(BTRFS_IOC_INO_LOOKUP) ret=%d, error: %m\n",
ret);
return ret;
}
len = strlen(ino_lookup_arg.name);
if (*path_len < len)
return -EOVERFLOW;
strcat(path, ino_lookup_arg.name);
(*path_len) -= len;
}
if (*path_len < btrfs_stack_root_ref_name_len(backref_item))
return -EOVERFLOW;
strncat(path, (char *)(backref_item + 1),
btrfs_stack_root_ref_name_len(backref_item));
(*path_len) -= btrfs_stack_root_ref_name_len(backref_item);
return 0;
}
struct subvol_info *subvol_uuid_search(int mnt_fd,
u64 root_id, const u8 *uuid, u64 transid,
const char *path,
enum subvol_search_type type)
{
int ret = 0;
struct btrfs_root_item root_item;
struct subvol_info *info = NULL;
switch (type) {
case subvol_search_by_received_uuid:
ret = btrfs_lookup_uuid_received_subvol_item(mnt_fd, uuid,
&root_id);
break;
case subvol_search_by_uuid:
ret = btrfs_lookup_uuid_subvol_item(mnt_fd, uuid, &root_id);
break;
case subvol_search_by_root_id:
break;
case subvol_search_by_path:
ret = btrfs_get_root_id_by_sub_path(mnt_fd, path, &root_id);
break;
default:
ret = -EINVAL;
break;
}
if (ret)
goto out;
ret = btrfs_read_root_item(mnt_fd, root_id, &root_item);
if (ret)
goto out;
info = calloc(1, sizeof(*info));
if (!info) {
ret = -ENOMEM;
goto out;
}
info->root_id = root_id;
memcpy(info->uuid, root_item.uuid, BTRFS_UUID_SIZE);
memcpy(info->received_uuid, root_item.received_uuid, BTRFS_UUID_SIZE);
memcpy(info->parent_uuid, root_item.parent_uuid, BTRFS_UUID_SIZE);
info->ctransid = btrfs_root_ctransid(&root_item);
info->otransid = btrfs_root_otransid(&root_item);
info->stransid = btrfs_root_stransid(&root_item);
info->rtransid = btrfs_root_rtransid(&root_item);
if (type == subvol_search_by_path) {
info->path = strdup(path);
if (!info->path) {
ret = -ENOMEM;
goto out;
}
} else {
info->path = malloc(PATH_MAX);
if (!info->path) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_subvolid_resolve(mnt_fd, info->path,
PATH_MAX, root_id);
}
out:
if (ret) {
if (info) {
free(info->path);
free(info);
}
return ERR_PTR(ret);
}
return info;
}