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-rw-r--r--super-recover.c346
1 files changed, 346 insertions, 0 deletions
diff --git a/super-recover.c b/super-recover.c
new file mode 100644
index 0000000..5920ea6
--- /dev/null
+++ b/super-recover.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright (C) 2013 Fujitsu. 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.
+ */
+
+#define _XOPEN_SOURCE 500
+#define _GNU_SOURCE 1
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <uuid/uuid.h>
+#include <errno.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <getopt.h>
+
+#include "kerncompat.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "list.h"
+#include "utils.h"
+#include "crc32c.h"
+#include "volumes.h"
+#include "commands.h"
+
+struct btrfs_recover_superblock {
+ struct btrfs_fs_devices *fs_devices;
+
+ struct list_head good_supers;
+ struct list_head bad_supers;
+
+ u64 max_generation;
+};
+
+struct super_block_record {
+ struct list_head list;
+
+ char *device_name;
+ struct btrfs_super_block sb;
+
+ u64 bytenr;
+};
+
+static
+void init_recover_superblock(struct btrfs_recover_superblock *recover)
+{
+ INIT_LIST_HEAD(&recover->good_supers);
+ INIT_LIST_HEAD(&recover->bad_supers);
+
+ recover->fs_devices = NULL;
+ recover->max_generation = 0;
+}
+
+static
+void free_recover_superblock(struct btrfs_recover_superblock *recover)
+{
+ struct btrfs_device *device;
+ struct super_block_record *record;
+
+ if (!recover->fs_devices)
+ return;
+
+ while (!list_empty(&recover->fs_devices->devices)) {
+ device = list_entry(recover->fs_devices->devices.next,
+ struct btrfs_device, dev_list);
+ list_del_init(&device->dev_list);
+ free(device->name);
+ free(device);
+ }
+ free(recover->fs_devices);
+
+ while (!list_empty(&recover->good_supers)) {
+ record = list_entry(recover->good_supers.next,
+ struct super_block_record, list);
+ list_del_init(&record->list);
+ free(record->device_name);
+ free(record);
+ }
+
+ while (!list_empty(&recover->bad_supers)) {
+ record = list_entry(recover->bad_supers.next,
+ struct super_block_record, list);
+ list_del_init(&record->list);
+ free(record->device_name);
+ free(record);
+ }
+}
+
+static int check_super(u64 bytenr, struct btrfs_super_block *sb)
+{
+ int csum_size = btrfs_super_csum_size(sb);
+ char result[csum_size];
+ u32 crc = ~(u32)0;
+
+ if (btrfs_super_bytenr(sb) != bytenr)
+ return 0;
+ if (sb->magic != cpu_to_le64(BTRFS_MAGIC))
+ return 0;
+
+ crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE,
+ crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+ btrfs_csum_final(crc, result);
+
+ return !memcmp(sb, &result, csum_size);
+}
+
+static int add_superblock_record(struct btrfs_super_block *sb, char *fname,
+ u64 bytenr, struct list_head *head)
+{
+ struct super_block_record *record;
+
+ record = malloc(sizeof(struct super_block_record));
+ if (!record)
+ return -ENOMEM;
+
+ record->device_name = strdup(fname);
+ if (!record->device_name) {
+ free(record);
+ return -ENOMEM;
+ }
+ memcpy(&record->sb, sb, sizeof(*sb));
+ record->bytenr = bytenr;
+ list_add_tail(&record->list, head);
+
+ return 0;
+}
+
+static int
+read_dev_supers(char *filename, struct btrfs_recover_superblock *recover)
+{
+ int i, ret, fd;
+ u8 buf[BTRFS_SUPER_INFO_SIZE];
+ u64 max_gen, bytenr;
+ /* just ignore errno that were set in btrfs_scan_fs_devices() */
+ errno = 0;
+
+ struct btrfs_super_block *sb = (struct btrfs_super_block *)buf;
+
+ fd = open(filename, O_RDONLY, 0666);
+ if (fd < 0)
+ return -errno;
+
+ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+ bytenr = btrfs_sb_offset(i);
+ ret = pread64(fd, buf, sizeof(buf), bytenr);
+ if (ret < sizeof(buf)) {
+ ret = -errno;
+ goto out;
+ }
+ ret = check_super(bytenr, sb);
+ if (ret) {
+ ret = add_superblock_record(sb, filename, bytenr,
+ &recover->good_supers);
+ if (ret)
+ goto out;
+ max_gen = btrfs_super_generation(sb);
+ if (max_gen > recover->max_generation)
+ recover->max_generation = max_gen;
+ } else {
+ ret = add_superblock_record(sb, filename, bytenr,
+ &recover->bad_supers);
+ if (ret)
+ goto out;
+ }
+ }
+out:
+ close(fd);
+ return ret;
+}
+
+static int read_fs_supers(struct btrfs_recover_superblock *recover)
+{
+ struct super_block_record *record;
+ struct super_block_record *next_record;
+ struct btrfs_device *dev;
+ int ret;
+ u64 gen;
+
+ list_for_each_entry(dev, &recover->fs_devices->devices,
+ dev_list) {
+ ret = read_dev_supers(dev->name, recover);
+ if (ret)
+ return ret;
+ }
+ list_for_each_entry_safe(record, next_record,
+ &recover->good_supers, list) {
+ gen = btrfs_super_generation(&record->sb);
+ if (gen < recover->max_generation)
+ list_move_tail(&record->list, &recover->bad_supers);
+ }
+
+ return 0;
+}
+
+static struct super_block_record *recover_get_good_super(
+ struct btrfs_recover_superblock *recover)
+{
+ struct super_block_record *record;
+ record = list_entry(recover->good_supers.next,
+ struct super_block_record, list);
+ return record;
+}
+
+static void print_all_devices(struct list_head *devices)
+{
+ struct btrfs_device *dev;
+
+ printf("All Devices:\n");
+ list_for_each_entry(dev, devices, dev_list) {
+ printf("\t");
+ printf("Device: id = %llu, name = %s\n",
+ dev->devid, dev->name);
+ }
+ printf("\n");
+}
+
+static void print_super_info(struct super_block_record *record)
+{
+ printf("\t\tdevice name = %s\n", record->device_name);
+ printf("\t\tsuperblock bytenr = %llu\n", record->bytenr);
+}
+
+static void print_all_supers(struct btrfs_recover_superblock *recover)
+{
+ struct super_block_record *record;
+
+ printf("\t[All good supers]:\n");
+ list_for_each_entry(record, &recover->good_supers, list) {
+ print_super_info(record);
+ printf("\n");
+ }
+
+ printf("\t[All bad supers]:\n");
+ list_for_each_entry(record, &recover->bad_supers, list) {
+ print_super_info(record);
+ printf("\n");
+ }
+ printf("\n");
+}
+
+static void recover_err_str(int ret)
+{
+ switch (ret) {
+ case 0:
+ printf("All supers are valid, no need to recover\n");
+ break;
+ case 1:
+ printf("Usage or syntax errors\n");
+ break;
+ case 2:
+ printf("Recovered bad superblocks successful\n");
+ break;
+ case 3:
+ printf("Failed to recover bad superblocks\n");
+ break;
+ case 4:
+ printf("Aborted to recover bad superblocks\n");
+ break;
+ default:
+ printf("Unknown recover result\n");
+ break;
+ }
+}
+
+int btrfs_recover_superblocks(const char *dname,
+ int verbose, int yes)
+{
+ int fd, ret;
+ struct btrfs_recover_superblock recover;
+ struct super_block_record *record;
+ struct btrfs_root *root = NULL;
+
+ fd = open(dname, O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr, "open %s error\n", dname);
+ return 1;
+ }
+ init_recover_superblock(&recover);
+
+ ret = btrfs_scan_fs_devices(fd, dname, &recover.fs_devices, 0, 0);
+ close(fd);
+ if (ret) {
+ ret = 1;
+ goto no_recover;
+ }
+
+ if (verbose)
+ print_all_devices(&recover.fs_devices->devices);
+
+ ret = read_fs_supers(&recover);
+ if (ret) {
+ ret = 1;
+ goto no_recover;
+ }
+ if (verbose) {
+ printf("Before Recovering:\n");
+ print_all_supers(&recover);
+ }
+
+ if (list_empty(&recover.bad_supers))
+ goto no_recover;
+
+ if (!yes) {
+ ret = ask_user("Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure?");
+ if (!ret) {
+ ret = 4;
+ goto no_recover;
+ }
+ }
+ record = recover_get_good_super(&recover);
+ root = open_ctree_with_broken_super(record->device_name,
+ record->bytenr, 1);
+ if (!root) {
+ ret = 3;
+ goto no_recover;
+ }
+ /* reset super_bytenr in order that we will rewite all supers */
+ root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
+ ret = write_all_supers(root);
+ if (!ret)
+ ret = 2;
+ else
+ ret = 3;
+
+ close_ctree(root);
+no_recover:
+ recover_err_str(ret);
+ free_recover_superblock(&recover);
+ return ret;
+}
+