| /* |
| * Copyright (C) 2011 Red Hat. 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 <unistd.h> |
| #include <fcntl.h> |
| #include <sys/stat.h> |
| #include <zlib.h> |
| #include "kerncompat.h" |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "print-tree.h" |
| #include "transaction.h" |
| #include "list.h" |
| #include "version.h" |
| #include "volumes.h" |
| #include "utils.h" |
| #include "crc32c.h" |
| |
| static u16 csum_size = 0; |
| static u64 search_objectid = BTRFS_ROOT_TREE_OBJECTID; |
| static u64 search_generation = 0; |
| static unsigned long search_level = 0; |
| |
| static void usage(void) |
| { |
| fprintf(stderr, "Usage: find-roots [-o search_objectid] " |
| "[ -g search_generation ] [ -l search_level ] <device>\n"); |
| } |
| |
| static int csum_block(void *buf, u32 len) |
| { |
| char *result; |
| u32 crc = ~(u32)0; |
| int ret = 0; |
| |
| result = malloc(csum_size * sizeof(char)); |
| if (!result) { |
| fprintf(stderr, "No memory\n"); |
| return 1; |
| } |
| |
| len -= BTRFS_CSUM_SIZE; |
| crc = crc32c(crc, buf + BTRFS_CSUM_SIZE, len); |
| btrfs_csum_final(crc, result); |
| |
| if (memcmp(buf, result, csum_size)) |
| ret = 1; |
| free(result); |
| return ret; |
| } |
| |
| static struct btrfs_root *open_ctree_broken(int fd, const char *device) |
| { |
| struct btrfs_fs_info *fs_info; |
| struct btrfs_super_block *disk_super; |
| struct btrfs_fs_devices *fs_devices = NULL; |
| struct extent_buffer *eb; |
| int ret; |
| |
| fs_info = btrfs_new_fs_info(0, BTRFS_SUPER_INFO_OFFSET); |
| if (!fs_info) { |
| fprintf(stderr, "Failed to allocate memory for fs_info\n"); |
| return NULL; |
| } |
| |
| ret = btrfs_scan_fs_devices(fd, device, &fs_devices, 0, 1); |
| if (ret) |
| goto out; |
| |
| fs_info->fs_devices = fs_devices; |
| |
| ret = btrfs_open_devices(fs_devices, O_RDONLY); |
| if (ret) |
| goto out_devices; |
| |
| disk_super = fs_info->super_copy; |
| ret = btrfs_read_dev_super(fs_devices->latest_bdev, |
| disk_super, fs_info->super_bytenr); |
| if (ret) { |
| printk("No valid btrfs found\n"); |
| goto out_devices; |
| } |
| |
| memcpy(fs_info->fsid, &disk_super->fsid, BTRFS_FSID_SIZE); |
| |
| ret = btrfs_check_fs_compatibility(disk_super, 0); |
| if (ret) |
| goto out_devices; |
| |
| ret = btrfs_setup_chunk_tree_and_device_map(fs_info); |
| if (ret) |
| goto out_chunk; |
| |
| eb = fs_info->chunk_root->node; |
| read_extent_buffer(eb, fs_info->chunk_tree_uuid, |
| btrfs_header_chunk_tree_uuid(eb), BTRFS_UUID_SIZE); |
| |
| return fs_info->chunk_root; |
| out_chunk: |
| free_extent_buffer(fs_info->chunk_root->node); |
| btrfs_cleanup_all_caches(fs_info); |
| out_devices: |
| btrfs_close_devices(fs_info->fs_devices); |
| out: |
| btrfs_free_fs_info(fs_info); |
| return NULL; |
| } |
| |
| static int search_iobuf(struct btrfs_root *root, void *iobuf, |
| size_t iobuf_size, off_t offset) |
| { |
| u64 gen = search_generation; |
| u64 objectid = search_objectid; |
| u32 size = btrfs_super_nodesize(root->fs_info->super_copy); |
| u8 level = search_level; |
| size_t block_off = 0; |
| |
| while (block_off < iobuf_size) { |
| void *block = iobuf + block_off; |
| struct btrfs_header *header = block; |
| u64 h_byte, h_level, h_gen, h_owner; |
| |
| // printf("searching %Lu\n", offset + block_off); |
| h_byte = btrfs_stack_header_bytenr(header); |
| h_owner = btrfs_stack_header_owner(header); |
| h_level = header->level; |
| h_gen = btrfs_stack_header_generation(header); |
| |
| if (h_owner != objectid) |
| goto next; |
| if (h_byte != (offset + block_off)) |
| goto next; |
| if (h_level < level) |
| goto next; |
| level = h_level; |
| if (csum_block(block, size)) { |
| fprintf(stderr, "Well block %Lu seems good, " |
| "but the csum doesn't match\n", |
| h_byte); |
| goto next; |
| } |
| if (h_gen != gen) { |
| fprintf(stderr, "Well block %Lu seems great, " |
| "but generation doesn't match, " |
| "have=%Lu, want=%Lu level %Lu\n", h_byte, |
| h_gen, gen, h_level); |
| goto next; |
| } |
| printf("Found tree root at %Lu gen %Lu level %Lu\n", h_byte, |
| h_gen, h_level); |
| return 0; |
| next: |
| block_off += size; |
| } |
| |
| return 1; |
| } |
| |
| static int read_physical(struct btrfs_root *root, int fd, u64 offset, |
| u64 bytenr, u64 len) |
| { |
| char *iobuf = malloc(len); |
| ssize_t done; |
| size_t total_read = 0; |
| int ret = 1; |
| |
| if (!iobuf) { |
| fprintf(stderr, "No memory\n"); |
| return -1; |
| } |
| |
| while (total_read < len) { |
| done = pread64(fd, iobuf + total_read, len - total_read, |
| bytenr + total_read); |
| if (done < 0) { |
| fprintf(stderr, "Failed to read: %s\n", |
| strerror(errno)); |
| ret = -1; |
| goto out; |
| } |
| total_read += done; |
| } |
| |
| ret = search_iobuf(root, iobuf, total_read, offset); |
| out: |
| free(iobuf); |
| return ret; |
| } |
| |
| static int find_root(struct btrfs_root *root) |
| { |
| struct btrfs_multi_bio *multi = NULL; |
| struct btrfs_device *device; |
| u64 metadata_offset = 0, metadata_size = 0; |
| off_t offset = 0; |
| off_t bytenr; |
| int fd; |
| int err; |
| int ret = 1; |
| |
| printf("Super think's the tree root is at %Lu, chunk root %Lu\n", |
| btrfs_super_root(root->fs_info->super_copy), |
| btrfs_super_chunk_root(root->fs_info->super_copy)); |
| |
| err = btrfs_next_metadata(&root->fs_info->mapping_tree, |
| &metadata_offset, &metadata_size); |
| if (err) |
| return ret; |
| |
| offset = metadata_offset; |
| while (1) { |
| u64 map_length = 4096; |
| u64 type; |
| |
| if (offset > |
| btrfs_super_total_bytes(root->fs_info->super_copy)) { |
| printf("Went past the fs size, exiting"); |
| break; |
| } |
| if (offset >= (metadata_offset + metadata_size)) { |
| err = btrfs_next_metadata(&root->fs_info->mapping_tree, |
| &metadata_offset, |
| &metadata_size); |
| if (err) { |
| printf("No more metdata to scan, exiting\n"); |
| break; |
| } |
| offset = metadata_offset; |
| } |
| err = __btrfs_map_block(&root->fs_info->mapping_tree, READ, |
| offset, &map_length, &type, |
| &multi, 0, NULL); |
| if (err) { |
| offset += map_length; |
| continue; |
| } |
| |
| if (!(type & BTRFS_BLOCK_GROUP_METADATA)) { |
| offset += map_length; |
| kfree(multi); |
| continue; |
| } |
| |
| device = multi->stripes[0].dev; |
| fd = device->fd; |
| bytenr = multi->stripes[0].physical; |
| kfree(multi); |
| |
| err = read_physical(root, fd, offset, bytenr, map_length); |
| if (!err) { |
| ret = 0; |
| break; |
| } else if (err < 0) { |
| ret = err; |
| break; |
| } |
| offset += map_length; |
| } |
| return ret; |
| } |
| |
| int main(int argc, char **argv) |
| { |
| struct btrfs_root *root; |
| int dev_fd; |
| int opt; |
| int ret; |
| |
| while ((opt = getopt(argc, argv, "l:o:g:")) != -1) { |
| switch(opt) { |
| errno = 0; |
| case 'o': |
| search_objectid = arg_strtou64(optarg); |
| break; |
| case 'g': |
| search_generation = arg_strtou64(optarg); |
| break; |
| case 'l': |
| search_level = arg_strtou64(optarg); |
| break; |
| default: |
| usage(); |
| exit(1); |
| } |
| } |
| |
| if (optind >= argc) { |
| usage(); |
| exit(1); |
| } |
| |
| dev_fd = open(argv[optind], O_RDONLY); |
| if (dev_fd < 0) { |
| fprintf(stderr, "Failed to open device %s\n", argv[optind]); |
| exit(1); |
| } |
| |
| root = open_ctree_broken(dev_fd, argv[optind]); |
| close(dev_fd); |
| |
| if (!root) { |
| fprintf(stderr, "Open ctree failed\n"); |
| exit(1); |
| } |
| |
| if (search_generation == 0) |
| search_generation = btrfs_super_generation(root->fs_info->super_copy); |
| |
| csum_size = btrfs_super_csum_size(root->fs_info->super_copy); |
| ret = find_root(root); |
| close_ctree(root); |
| return ret; |
| } |