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