diff options
| -rw-r--r-- | Documentation/btrfs-check.txt | 2 | ||||
| -rw-r--r-- | cmds-check.c | 125 |
2 files changed, 123 insertions, 4 deletions
diff --git a/Documentation/btrfs-check.txt b/Documentation/btrfs-check.txt index 027032b2..961d5aec 100644 --- a/Documentation/btrfs-check.txt +++ b/Documentation/btrfs-check.txt @@ -30,6 +30,8 @@ try to repair the filesystem. create a new CRC tree. --init-extent-tree:: create a new extent tree. +--check-data-csum:: +verify checkums of data blocks. EXIT STATUS ----------- diff --git a/cmds-check.c b/cmds-check.c index 978ceeec..a0720cd5 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -54,6 +54,7 @@ static LIST_HEAD(delete_items); static int repair = 0; static int no_holes = 0; static int init_extent_tree = 0; +static int check_data_csum = 0; struct extent_backref { struct list_head list; @@ -3611,6 +3612,109 @@ static int check_space_cache(struct btrfs_root *root) return error ? -EINVAL : 0; } +static int read_extent_data(struct btrfs_root *root, char *data, + u64 logical, u64 *len, int mirror) +{ + u64 offset = 0; + struct btrfs_multi_bio *multi = NULL; + struct btrfs_fs_info *info = root->fs_info; + struct btrfs_device *device; + int ret = 0; + u64 max_len = *len; + + ret = btrfs_map_block(&info->mapping_tree, READ, logical, len, + &multi, mirror, NULL); + if (ret) { + fprintf(stderr, "Couldn't map the block %llu\n", + logical + offset); + goto err; + } + device = multi->stripes[0].dev; + + if (device->fd == 0) + goto err; + if (*len > max_len) + *len = max_len; + + ret = pread64(device->fd, data, *len, multi->stripes[0].physical); + if (ret != *len) + ret = -EIO; + else + ret = 0; +err: + kfree(multi); + return ret; +} + +static int check_extent_csums(struct btrfs_root *root, u64 bytenr, + u64 num_bytes, unsigned long leaf_offset, + struct extent_buffer *eb) { + + u64 offset = 0; + u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); + char *data; + unsigned long csum_offset; + u32 csum; + u32 csum_expected; + u64 read_len; + u64 data_checked = 0; + u64 tmp; + int ret = 0; + int mirror; + int num_copies; + + if (num_bytes % root->sectorsize) + return -EINVAL; + + data = malloc(num_bytes); + if (!data) + return -ENOMEM; + + while (offset < num_bytes) { + mirror = 0; +again: + read_len = num_bytes - offset; + /* read as much space once a time */ + ret = read_extent_data(root, data + offset, + bytenr + offset, &read_len, mirror); + if (ret) + goto out; + data_checked = 0; + /* verify every 4k data's checksum */ + while (data_checked < read_len) { + csum = ~(u32)0; + tmp = offset + data_checked; + + csum = btrfs_csum_data(NULL, (char *)data + tmp, + csum, root->sectorsize); + btrfs_csum_final(csum, (char *)&csum); + + csum_offset = leaf_offset + + tmp / root->sectorsize * csum_size; + read_extent_buffer(eb, (char *)&csum_expected, + csum_offset, csum_size); + /* try another mirror */ + if (csum != csum_expected) { + fprintf(stderr, "mirror %d bytenr %llu csum %u expected csum %u\n", + mirror, bytenr + tmp, + csum, csum_expected); + num_copies = btrfs_num_copies( + &root->fs_info->mapping_tree, + bytenr, num_bytes); + if (mirror < num_copies - 1) { + mirror += 1; + goto again; + } + } + data_checked += root->sectorsize; + } + offset += read_len; + } +out: + free(data); + return ret; +} + static int check_extent_exists(struct btrfs_root *root, u64 bytenr, u64 num_bytes) { @@ -3748,6 +3852,8 @@ static int check_csums(struct btrfs_root *root) u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); int errors = 0; int ret; + u64 data_len; + unsigned long leaf_offset; root = root->fs_info->csum_root; @@ -3789,6 +3895,16 @@ static int check_csums(struct btrfs_root *root) continue; } + data_len = (btrfs_item_size_nr(leaf, path->slots[0]) / + csum_size) * root->sectorsize; + if (!check_data_csum) + goto skip_csum_check; + leaf_offset = btrfs_item_ptr_offset(leaf, path->slots[0]); + ret = check_extent_csums(root, key.offset, data_len, + leaf_offset, leaf); + if (ret) + break; +skip_csum_check: if (!num_bytes) { offset = key.offset; } else if (key.offset != offset + num_bytes) { @@ -3802,9 +3918,7 @@ static int check_csums(struct btrfs_root *root) offset = key.offset; num_bytes = 0; } - - num_bytes += (btrfs_item_size_nr(leaf, path->slots[0]) / - csum_size) * root->sectorsize; + num_bytes += data_len; path->slots[0]++; } @@ -6428,6 +6542,7 @@ static struct option long_options[] = { { "repair", 0, NULL, 0 }, { "init-csum-tree", 0, NULL, 0 }, { "init-extent-tree", 0, NULL, 0 }, + { "check-data-csum", 0, NULL, 0 }, { "backup", 0, NULL, 0 }, { "qgroup-report", 0, NULL, 'Q' }, { NULL, 0, NULL, 0} @@ -6442,6 +6557,7 @@ const char * const cmd_check_usage[] = { "--repair try to repair the filesystem", "--init-csum-tree create a new CRC tree", "--init-extent-tree create a new extent tree", + "--check-data-csum verify checkums of data blocks", "--qgroup-report print a report on qgroup consistency", NULL }; @@ -6505,8 +6621,9 @@ int cmd_check(int argc, char **argv) ctree_flags |= (OPEN_CTREE_WRITES | OPEN_CTREE_NO_BLOCK_GROUPS); repair = 1; + } else if (option_index == 4) { + check_data_csum = 1; } - } argc = argc - optind; |