Wang Shilong
2014-May-08 01:26 UTC
[PATCH] Btrfs-progs: fsck: add an option to check data csums
This patch adds an option '--check-data-csum' to verify data csums. fsck won't check data csums unless users specify this option explictly. Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> --- Documentation/btrfs-check.txt | 2 + cmds-check.c | 122 ++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 120 insertions(+), 4 deletions(-) diff --git a/Documentation/btrfs-check.txt b/Documentation/btrfs-check.txt index 485a49c..bc10755 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:: +check data csums. EXIT STATUS ----------- diff --git a/cmds-check.c b/cmds-check.c index 103efc5..b53d49c 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -53,6 +53,7 @@ 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; @@ -3634,6 +3635,106 @@ 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 read_len; + unsigned long bytes_left = len; + + while (bytes_left) { + read_len = bytes_left; + device = NULL; + ret = btrfs_map_block(&info->mapping_tree, READ, + logical + offset, &read_len, &multi, + mirror, NULL); + if (ret) { + fprintf(stderr, "Couldn't map the block %llu\n", + logical + offset); + goto error; + } + device = multi->stripes[0].dev; + + if (device->fd == 0) + goto error; + + if (read_len > root->sectorsize) + read_len = root->sectorsize; + if (read_len > bytes_left) + read_len = bytes_left; + + ret = pread64(device->fd, data + offset, read_len, + multi->stripes[0].physical); + if (ret != read_len) + goto error; + offset += read_len; + bytes_left -= read_len; + kfree(multi); + multi = NULL; + } + return 0; +error: + kfree(multi); + return -EIO; +} + +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; + u32 crc; + unsigned long tmp; + char result[csum_size]; + char out[csum_size]; + int ret = 0; + __s64 cmp; + int mirror; + int num_copies = btrfs_num_copies(&root->fs_info->mapping_tree, + bytenr, num_bytes); + + BUG_ON(num_bytes % root->sectorsize); + data = malloc(root->sectorsize); + if (!data) + return -ENOMEM; + + while (offset < num_bytes) { + mirror = 0; +again: + ret = read_extent_data(root, data, bytenr + offset, + root->sectorsize, mirror); + if (ret) + goto out; + + crc = ~(u32)0; + crc = btrfs_csum_data(NULL, (char *)data, crc, + root->sectorsize); + btrfs_csum_final(crc, result); + + tmp = leaf_offset + offset / root->sectorsize * csum_size; + read_extent_buffer(eb, out, tmp, csum_size); + cmp = memcmp(out, result, csum_size); + if (cmp) { + fprintf(stderr, "mirror: %d range bytenr: %llu, len: %d checksum mismatch\n", + mirror, bytenr + offset, root->sectorsize); + if (mirror < num_copies - 1) { + mirror += 1; + goto again; + } + } + offset += root->sectorsize; + } +out: + free(data); + return ret; +} + static int check_extent_exists(struct btrfs_root *root, u64 bytenr, u64 num_bytes) { @@ -3771,6 +3872,8 @@ 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; @@ -3812,6 +3915,16 @@ 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) { @@ -3825,9 +3938,7 @@ 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]++; } @@ -6665,6 +6776,7 @@ 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 }, { NULL, 0, NULL, 0} }; @@ -6678,6 +6790,7 @@ 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 check data csums", NULL }; @@ -6736,8 +6849,9 @@ 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; -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html