uuid-tree.c

   1 /*
   2  * Copyright (C) STRATO AG 2013.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <uuid/uuid.h>
  21 #include <sys/ioctl.h>
  22 #include "ctree.h"
  23 #include "transaction.h"
  24 #include "disk-io.h"
  25 #include "print-tree.h"
  26
  27
  28 static void btrfs_uuid_to_key(const u8 *uuid, u64 *key_objectid,
  29                               u64 *key_offset)
  30 {
  31         *key_objectid = get_unaligned_le64(uuid);
  32         *key_offset = get_unaligned_le64(uuid + sizeof(u64));
  33 }
  34
  35
  36 /* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
  37 static int btrfs_uuid_tree_lookup_any(int fd, const u8 *uuid, u8 type,
  38                                       u64 *subid)
  39 {
  40         int ret;
  41         u64 key_objectid = 0;
  42         u64 key_offset;
  43         struct btrfs_ioctl_search_args search_arg;
  44         struct btrfs_ioctl_search_header *search_header;
  45         u32 item_size;
  46         __le64 lesubid;
  47
  48         btrfs_uuid_to_key(uuid, &key_objectid, &key_offset);
  49
  50         memset(&search_arg, 0, sizeof(search_arg));
  51         search_arg.key.tree_id = BTRFS_UUID_TREE_OBJECTID;
  52         search_arg.key.min_objectid = key_objectid;
  53         search_arg.key.max_objectid = key_objectid;
  54         search_arg.key.min_type = type;
  55         search_arg.key.max_type = type;
  56         search_arg.key.min_offset = key_offset;
  57         search_arg.key.max_offset = key_offset;
  58         search_arg.key.max_transid = (u64)-1;
  59         search_arg.key.nr_items = 1;
  60         ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search_arg);
  61         if (ret < 0) {
  62                 fprintf(stderr,
  63                         "ioctl(BTRFS_IOC_TREE_SEARCH, uuid, key %016llx, UUID_KEY, %016llx) ret=%d, error: %m\n",
  64                         (unsigned long long)key_objectid,
  65                         (unsigned long long)key_offset, ret);
  66                 ret = -ENOENT;
  67                 goto out;
  68         }
  69
  70         if (search_arg.key.nr_items < 1) {
  71                 ret = -ENOENT;
  72                 goto out;
  73         }
  74         search_header = (struct btrfs_ioctl_search_header *)(search_arg.buf);
  75         item_size = btrfs_search_header_len(search_header);
  76         if ((item_size & (sizeof(u64) - 1)) || item_size == 0) {
  77                 printf("btrfs: uuid item with illegal size %lu!\n",
  78                        (unsigned long)item_size);
  79                 ret = -ENOENT;
  80                 goto out;
  81         } else {
  82                 ret = 0;
  83         }
  84
  85         /* return first stored id */
  86         memcpy(&lesubid, search_header + 1, sizeof(lesubid));
  87         *subid = le64_to_cpu(lesubid);
  88
  89 out:
  90         return ret;
  91 }
  92
  93 int btrfs_lookup_uuid_subvol_item(int fd, const u8 *uuid, u64 *subvol_id)
  94 {
  95         return btrfs_uuid_tree_lookup_any(fd, uuid, BTRFS_UUID_KEY_SUBVOL,
  96                                           subvol_id);
  97 }
  98
  99 int btrfs_lookup_uuid_received_subvol_item(int fd, const u8 *uuid,
 100                                            u64 *subvol_id)
 101 {
 102         return btrfs_uuid_tree_lookup_any(fd, uuid,
 103                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
 104                                           subvol_id);
 105 }