super-recover.c

   1 /*
   2  * Copyright (C) 2013 FUJITSU LIMITED.  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
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <fcntl.h>
  22 #include <sys/stat.h>
  23 #include <uuid/uuid.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <ctype.h>
  27 #include <getopt.h>
  28
  29 #include "kerncompat.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "list.h"
  33 #include "utils.h"
  34 #include "crc32c.h"
  35 #include "volumes.h"
  36 #include "commands.h"
  37
  38 struct btrfs_recover_superblock {
  39         struct btrfs_fs_devices *fs_devices;
  40
  41         struct list_head good_supers;
  42         struct list_head bad_supers;
  43
  44         u64 max_generation;
  45 };
  46
  47 struct super_block_record {
  48         struct list_head list;
  49
  50         char *device_name;
  51         struct btrfs_super_block sb;
  52
  53         u64 bytenr;
  54 };
  55
  56 static
  57 void init_recover_superblock(struct btrfs_recover_superblock *recover)
  58 {
  59         INIT_LIST_HEAD(&recover->good_supers);
  60         INIT_LIST_HEAD(&recover->bad_supers);
  61
  62         recover->fs_devices = NULL;
  63         recover->max_generation = 0;
  64 }
  65
  66 static
  67 void free_recover_superblock(struct btrfs_recover_superblock *recover)
  68 {
  69         struct super_block_record *record;
  70
  71         if (!recover->fs_devices)
  72                 return;
  73
  74         while (!list_empty(&recover->good_supers)) {
  75                 record = list_entry(recover->good_supers.next,
  76                                 struct super_block_record, list);
  77                 list_del_init(&record->list);
  78                 free(record->device_name);
  79                 free(record);
  80         }
  81
  82         while (!list_empty(&recover->bad_supers)) {
  83                 record = list_entry(recover->bad_supers.next,
  84                                 struct super_block_record, list);
  85                 list_del_init(&record->list);
  86                 free(record->device_name);
  87                 free(record);
  88         }
  89 }
  90
  91 static int check_super(u64 bytenr, struct btrfs_super_block *sb)
  92 {
  93         int csum_size = btrfs_super_csum_size(sb);
  94         char result[csum_size];
  95         u32 crc = ~(u32)0;
  96
  97         if (btrfs_super_bytenr(sb) != bytenr)
  98                 return 0;
  99         if (sb->magic != cpu_to_le64(BTRFS_MAGIC))
 100                 return 0;
 101
 102         crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE,
 103                         crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
 104         btrfs_csum_final(crc, result);
 105
 106         return !memcmp(sb, &result, csum_size);
 107 }
 108
 109 static int add_superblock_record(struct btrfs_super_block *sb, char *fname,
 110                         u64 bytenr, struct list_head *head)
 111 {
 112         struct super_block_record *record;
 113
 114         record = malloc(sizeof(struct super_block_record));
 115         if (!record)
 116                 return -ENOMEM;
 117
 118         record->device_name = strdup(fname);
 119         if (!record->device_name) {
 120                 free(record);
 121                 return -ENOMEM;
 122         }
 123         memcpy(&record->sb, sb, sizeof(*sb));
 124         record->bytenr = bytenr;
 125         list_add_tail(&record->list, head);
 126
 127         return 0;
 128 }
 129
 130 static int
 131 read_dev_supers(char *filename, struct btrfs_recover_superblock *recover)
 132 {
 133         int i, ret, fd;
 134         u8 buf[BTRFS_SUPER_INFO_SIZE];
 135         u64 max_gen, bytenr;
 136         /* just ignore errno that were set in btrfs_scan_fs_devices() */
 137         errno = 0;
 138
 139         struct btrfs_super_block *sb = (struct btrfs_super_block *)buf;
 140
 141         fd = open(filename, O_RDONLY, 0666);
 142         if (fd < 0)
 143                 return -errno;
 144
 145         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 146                 bytenr = btrfs_sb_offset(i);
 147                 ret = pread64(fd, buf, sizeof(buf), bytenr);
 148                 if (ret < sizeof(buf)) {
 149                         ret = -errno;
 150                         goto out;
 151                 }
 152                 ret = check_super(bytenr, sb);
 153                 if (ret) {
 154                         ret = add_superblock_record(sb, filename, bytenr,
 155                                                         &recover->good_supers);
 156                         if (ret)
 157                                 goto out;
 158                         max_gen = btrfs_super_generation(sb);
 159                         if (max_gen > recover->max_generation)
 160                                 recover->max_generation = max_gen;
 161                 } else {
 162                         ret = add_superblock_record(sb, filename, bytenr,
 163                                                 &recover->bad_supers);
 164                         if (ret)
 165                                 goto out;
 166                 }
 167         }
 168 out:
 169         close(fd);
 170         return ret;
 171 }
 172
 173 static int read_fs_supers(struct btrfs_recover_superblock *recover)
 174 {
 175         struct super_block_record *record;
 176         struct super_block_record *next_record;
 177         struct btrfs_device *dev;
 178         int ret;
 179         u64 gen;
 180
 181         list_for_each_entry(dev, &recover->fs_devices->devices,
 182                                 dev_list) {
 183                 ret = read_dev_supers(dev->name, recover);
 184                 if (ret)
 185                         return ret;
 186         }
 187         list_for_each_entry_safe(record, next_record,
 188                         &recover->good_supers, list) {
 189                 gen = btrfs_super_generation(&record->sb);
 190                 if (gen < recover->max_generation)
 191                         list_move_tail(&record->list, &recover->bad_supers);
 192         }
 193
 194         return 0;
 195 }
 196
 197 static struct super_block_record *recover_get_good_super(
 198                                 struct btrfs_recover_superblock *recover)
 199 {
 200         struct super_block_record *record;
 201         record = list_entry(recover->good_supers.next,
 202                                 struct super_block_record, list);
 203         return record;
 204 }
 205
 206 static void print_all_devices(struct list_head *devices)
 207 {
 208         struct btrfs_device *dev;
 209
 210         printf("All Devices:\n");
 211         list_for_each_entry(dev, devices, dev_list) {
 212                 printf("\t");
 213                 printf("Device: id = %llu, name = %s\n",
 214                         dev->devid, dev->name);
 215         }
 216         printf("\n");
 217 }
 218
 219 static void print_super_info(struct super_block_record *record)
 220 {
 221         printf("\t\tdevice name = %s\n", record->device_name);
 222         printf("\t\tsuperblock bytenr = %llu\n", record->bytenr);
 223 }
 224
 225 static void print_all_supers(struct btrfs_recover_superblock *recover)
 226 {
 227         struct super_block_record *record;
 228
 229         printf("\t[All good supers]:\n");
 230         list_for_each_entry(record, &recover->good_supers, list) {
 231                 print_super_info(record);
 232                 printf("\n");
 233         }
 234
 235         printf("\t[All bad supers]:\n");
 236         list_for_each_entry(record, &recover->bad_supers, list) {
 237                 print_super_info(record);
 238                 printf("\n");
 239         }
 240         printf("\n");
 241 }
 242
 243 static void recover_err_str(int ret)
 244 {
 245         switch (ret) {
 246         case 0:
 247                 printf("All supers are valid, no need to recover\n");
 248                 break;
 249         case 1:
 250                 printf("Usage or syntax errors\n");
 251                 break;
 252         case 2:
 253                 printf("Recovered bad superblocks successful\n");
 254                 break;
 255         case 3:
 256                 printf("Failed to recover bad superblocks\n");
 257                 break;
 258         case 4:
 259                 printf("Aborted to recover bad superblocks\n");
 260                 break;
 261         default:
 262                 printf("Unknown recover result\n");
 263                 break;
 264         }
 265 }
 266
 267 int btrfs_recover_superblocks(const char *dname,
 268                         int verbose, int yes)
 269 {
 270         int fd, ret;
 271         struct btrfs_recover_superblock recover;
 272         struct super_block_record *record;
 273         struct btrfs_root *root = NULL;
 274
 275         fd = open(dname, O_RDONLY);
 276         if (fd < 0) {
 277                 fprintf(stderr, "open %s error\n", dname);
 278                 return 1;
 279         }
 280         init_recover_superblock(&recover);
 281
 282         ret = btrfs_scan_fs_devices(fd, dname, &recover.fs_devices, 0, 1, 0);
 283         close(fd);
 284         if (ret) {
 285                 ret = 1;
 286                 goto no_recover;
 287         }
 288
 289         if (verbose)
 290                 print_all_devices(&recover.fs_devices->devices);
 291
 292         ret = read_fs_supers(&recover);
 293         if (ret) {
 294                 ret = 1;
 295                 goto no_recover;
 296         }
 297         if (verbose) {
 298                 printf("Before Recovering:\n");
 299                 print_all_supers(&recover);
 300         }
 301
 302         if (list_empty(&recover.bad_supers))
 303                 goto no_recover;
 304
 305         if (!yes) {
 306                 ret = ask_user("Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure?");
 307                 if (!ret) {
 308                         ret = 4;
 309                         goto no_recover;
 310                 }
 311         }
 312         record = recover_get_good_super(&recover);
 313         root = open_ctree(record->device_name, record->bytenr,
 314                           OPEN_CTREE_RECOVER_SUPER | OPEN_CTREE_WRITES);
 315         if (!root) {
 316                 ret = 3;
 317                 goto no_recover;
 318         }
 319         /* reset super_bytenr in order that we will rewrite all supers */
 320         root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
 321         ret = write_all_supers(root);
 322         if (!ret)
 323                 ret = 2;
 324         else
 325                 ret = 3;
 326
 327         close_ctree(root);
 328 no_recover:
 329         recover_err_str(ret);
 330         free_recover_superblock(&recover);
 331         /* check if we have freed fs_devices in close_ctree() */
 332         if (!root)
 333                 btrfs_close_devices(recover.fs_devices);
 334         return ret;
 335 }
 336