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 #define _XOPEN_SOURCE 500
  20 #define _GNU_SOURCE 1
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <fcntl.h>
  25 #include <sys/stat.h>
  26 #include <uuid/uuid.h>
  27 #include <errno.h>
  28 #include <unistd.h>
  29 #include <ctype.h>
  30 #include <getopt.h>
  31
  32 #include "kerncompat.h"
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "list.h"
  36 #include "utils.h"
  37 #include "crc32c.h"
  38 #include "volumes.h"
  39 #include "commands.h"
  40
  41 struct btrfs_recover_superblock {
  42         struct btrfs_fs_devices *fs_devices;
  43
  44         struct list_head good_supers;
  45         struct list_head bad_supers;
  46
  47         u64 max_generation;
  48 };
  49
  50 struct super_block_record {
  51         struct list_head list;
  52
  53         char *device_name;
  54         struct btrfs_super_block sb;
  55
  56         u64 bytenr;
  57 };
  58
  59 static
  60 void init_recover_superblock(struct btrfs_recover_superblock *recover)
  61 {
  62         INIT_LIST_HEAD(&recover->good_supers);
  63         INIT_LIST_HEAD(&recover->bad_supers);
  64
  65         recover->fs_devices = NULL;
  66         recover->max_generation = 0;
  67 }
  68
  69 static
  70 void free_recover_superblock(struct btrfs_recover_superblock *recover)
  71 {
  72         struct btrfs_device *device;
  73         struct super_block_record *record;
  74
  75         if (!recover->fs_devices)
  76                 return;
  77
  78         while (!list_empty(&recover->fs_devices->devices)) {
  79                 device = list_entry(recover->fs_devices->devices.next,
  80                                 struct btrfs_device, dev_list);
  81                 list_del_init(&device->dev_list);
  82                 free(device->name);
  83                 free(device);
  84         }
  85         free(recover->fs_devices);
  86
  87         while (!list_empty(&recover->good_supers)) {
  88                 record = list_entry(recover->good_supers.next,
  89                                 struct super_block_record, list);
  90                 list_del_init(&record->list);
  91                 free(record->device_name);
  92                 free(record);
  93         }
  94
  95         while (!list_empty(&recover->bad_supers)) {
  96                 record = list_entry(recover->bad_supers.next,
  97                                 struct super_block_record, list);
  98                 list_del_init(&record->list);
  99                 free(record->device_name);
 100                 free(record);
 101         }
 102 }
 103
 104 static int check_super(u64 bytenr, struct btrfs_super_block *sb)
 105 {
 106         int csum_size = btrfs_super_csum_size(sb);
 107         char result[csum_size];
 108         u32 crc = ~(u32)0;
 109
 110         if (btrfs_super_bytenr(sb) != bytenr)
 111                 return 0;
 112         if (sb->magic != cpu_to_le64(BTRFS_MAGIC))
 113                 return 0;
 114
 115         crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE,
 116                         crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
 117         btrfs_csum_final(crc, result);
 118
 119         return !memcmp(sb, &result, csum_size);
 120 }
 121
 122 static int add_superblock_record(struct btrfs_super_block *sb, char *fname,
 123                         u64 bytenr, struct list_head *head)
 124 {
 125         struct super_block_record *record;
 126
 127         record = malloc(sizeof(struct super_block_record));
 128         if (!record)
 129                 return -ENOMEM;
 130
 131         record->device_name = strdup(fname);
 132         if (!record->device_name) {
 133                 free(record);
 134                 return -ENOMEM;
 135         }
 136         memcpy(&record->sb, sb, sizeof(*sb));
 137         record->bytenr = bytenr;
 138         list_add_tail(&record->list, head);
 139
 140         return 0;
 141 }
 142
 143 static int
 144 read_dev_supers(char *filename, struct btrfs_recover_superblock *recover)
 145 {
 146         int i, ret, fd;
 147         u8 buf[BTRFS_SUPER_INFO_SIZE];
 148         u64 max_gen, bytenr;
 149         /* just ignore errno that were set in btrfs_scan_fs_devices() */
 150         errno = 0;
 151
 152         struct btrfs_super_block *sb = (struct btrfs_super_block *)buf;
 153
 154         fd = open(filename, O_RDONLY, 0666);
 155         if (fd < 0)
 156                 return -errno;
 157
 158         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 159                 bytenr = btrfs_sb_offset(i);
 160                 ret = pread64(fd, buf, sizeof(buf), bytenr);
 161                 if (ret < sizeof(buf)) {
 162                         ret = -errno;
 163                         goto out;
 164                 }
 165                 ret = check_super(bytenr, sb);
 166                 if (ret) {
 167                         ret = add_superblock_record(sb, filename, bytenr,
 168                                                         &recover->good_supers);
 169                         if (ret)
 170                                 goto out;
 171                         max_gen = btrfs_super_generation(sb);
 172                         if (max_gen > recover->max_generation)
 173                                 recover->max_generation = max_gen;
 174                 } else {
 175                         ret = add_superblock_record(sb, filename, bytenr,
 176                                                 &recover->bad_supers);
 177                         if (ret)
 178                                 goto out;
 179                 }
 180         }
 181 out:
 182         close(fd);
 183         return ret;
 184 }
 185
 186 static int read_fs_supers(struct btrfs_recover_superblock *recover)
 187 {
 188         struct super_block_record *record;
 189         struct super_block_record *next_record;
 190         struct btrfs_device *dev;
 191         int ret;
 192         u64 gen;
 193
 194         list_for_each_entry(dev, &recover->fs_devices->devices,
 195                                 dev_list) {
 196                 ret = read_dev_supers(dev->name, recover);
 197                 if (ret)
 198                         return ret;
 199         }
 200         list_for_each_entry_safe(record, next_record,
 201                         &recover->good_supers, list) {
 202                 gen = btrfs_super_generation(&record->sb);
 203                 if (gen < recover->max_generation)
 204                         list_move_tail(&record->list, &recover->bad_supers);
 205         }
 206
 207         return 0;
 208 }
 209
 210 static struct super_block_record *recover_get_good_super(
 211                                 struct btrfs_recover_superblock *recover)
 212 {
 213         struct super_block_record *record;
 214         record = list_entry(recover->good_supers.next,
 215                                 struct super_block_record, list);
 216         return record;
 217 }
 218
 219 static void print_all_devices(struct list_head *devices)
 220 {
 221         struct btrfs_device *dev;
 222
 223         printf("All Devices:\n");
 224         list_for_each_entry(dev, devices, dev_list) {
 225                 printf("\t");
 226                 printf("Device: id = %llu, name = %s\n",
 227                         dev->devid, dev->name);
 228         }
 229         printf("\n");
 230 }
 231
 232 static void print_super_info(struct super_block_record *record)
 233 {
 234         printf("\t\tdevice name = %s\n", record->device_name);
 235         printf("\t\tsuperblock bytenr = %llu\n", record->bytenr);
 236 }
 237
 238 static void print_all_supers(struct btrfs_recover_superblock *recover)
 239 {
 240         struct super_block_record *record;
 241
 242         printf("\t[All good supers]:\n");
 243         list_for_each_entry(record, &recover->good_supers, list) {
 244                 print_super_info(record);
 245                 printf("\n");
 246         }
 247
 248         printf("\t[All bad supers]:\n");
 249         list_for_each_entry(record, &recover->bad_supers, list) {
 250                 print_super_info(record);
 251                 printf("\n");
 252         }
 253         printf("\n");
 254 }
 255
 256 static void recover_err_str(int ret)
 257 {
 258         switch (ret) {
 259         case 0:
 260                 printf("All supers are valid, no need to recover\n");
 261                 break;
 262         case 1:
 263                 printf("Usage or syntax errors\n");
 264                 break;
 265         case 2:
 266                 printf("Recovered bad superblocks successful\n");
 267                 break;
 268         case 3:
 269                 printf("Failed to recover bad superblocks\n");
 270                 break;
 271         case 4:
 272                 printf("Aborted to recover bad superblocks\n");
 273                 break;
 274         default:
 275                 printf("Unknown recover result\n");
 276                 break;
 277         }
 278 }
 279
 280 int btrfs_recover_superblocks(const char *dname,
 281                         int verbose, int yes)
 282 {
 283         int fd, ret;
 284         struct btrfs_recover_superblock recover;
 285         struct super_block_record *record;
 286         struct btrfs_root *root = NULL;
 287
 288         fd = open(dname, O_RDONLY);
 289         if (fd < 0) {
 290                 fprintf(stderr, "open %s error\n", dname);
 291                 return 1;
 292         }
 293         init_recover_superblock(&recover);
 294
 295         ret = btrfs_scan_fs_devices(fd, dname, &recover.fs_devices, 0, 0, 1);
 296         close(fd);
 297         if (ret) {
 298                 ret = 1;
 299                 goto no_recover;
 300         }
 301
 302         if (verbose)
 303                 print_all_devices(&recover.fs_devices->devices);
 304
 305         ret = read_fs_supers(&recover);
 306         if (ret) {
 307                 ret = 1;
 308                 goto no_recover;
 309         }
 310         if (verbose) {
 311                 printf("Before Recovering:\n");
 312                 print_all_supers(&recover);
 313         }
 314
 315         if (list_empty(&recover.bad_supers))
 316                 goto no_recover;
 317
 318         if (!yes) {
 319                 ret = ask_user("Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure?");
 320                 if (!ret) {
 321                         ret = 4;
 322                         goto no_recover;
 323                 }
 324         }
 325         record = recover_get_good_super(&recover);
 326         root = open_ctree(record->device_name, record->bytenr,
 327                           OPEN_CTREE_RECOVER_SUPER | OPEN_CTREE_WRITES);
 328         if (!root) {
 329                 ret = 3;
 330                 goto no_recover;
 331         }
 332         /* reset super_bytenr in order that we will rewite all supers */
 333         root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
 334         ret = write_all_supers(root);
 335         if (!ret)
 336                 ret = 2;
 337         else
 338                 ret = 3;
 339
 340         close_ctree(root);
 341 no_recover:
 342         recover_err_str(ret);
 343         free_recover_superblock(&recover);
 344         return ret;
 345 }
 346