Introduce a new function, scrub_data_mirror(), to check mirror based data blocks.
It can also accept @data parameter to use in-memory data instead of reading them out of disk. This is a handy feature for RAID5/6 recovery verification code. Signed-off-by: Qu Wenruo <[email protected]> Signed-off-by: Su Yue <[email protected]> --- scrub.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) diff --git a/scrub.c b/scrub.c index 1ea2645b..d59be25d 100644 --- a/scrub.c +++ b/scrub.c @@ -191,3 +191,100 @@ out: free_extent_buffer(eb); return ret; } + +/* + * Scrub one data mirror given by @start @len and @mirror, or @data + * If @data is not given, try to read it from disk. + * This function will try to read out all the data then check sum. + * + * If @data is given, just use the data. + * This behavior is useful for RAID5/6 recovery code to verify recovered data. + * + * Return 0 if everything is OK. + * Return <0 if something goes wrong, and @scrub_ctx accounting will be updated + * if it's a data corruption. + */ +static int scrub_data_mirror(struct btrfs_fs_info *fs_info, + struct btrfs_scrub_progress *scrub_ctx, + char *data, u64 start, u64 len, int mirror) +{ + u64 cur = 0; + u32 sectorsize = fs_info->tree_root->sectorsize; + u32 data_csum; + u32 *csums = NULL; + char *buf = NULL; + int ret = 0; + int err = 0; + unsigned long *csum_bitmap = NULL; + + if (!data) { + buf = malloc(len); + if (!buf) + return -ENOMEM; + /* Read out as much data as possible to speed up read */ + while (cur < len) { + u64 read_len = len - cur; + + ret = read_extent_data(fs_info->tree_root, buf + cur, + start + cur, &read_len, mirror); + if (ret < 0) { + error("failed to read out data at logical bytenr %llu mirror %d", + start + cur, mirror); + scrub_ctx->read_errors++; + goto out; + } + scrub_ctx->data_bytes_scrubbed += read_len; + cur += read_len; + } + } else { + buf = data; + } + + /* Alloc and Check csums */ + csums = malloc(len / sectorsize * sizeof(data_csum)); + if (!csums) { + ret = -ENOMEM; + goto out; + } + csum_bitmap = malloc(round_up(len / sectorsize, BITS_PER_BYTE)); + if (!csum_bitmap) { + ret = -ENOMEM; + goto out; + } + + ret = btrfs_read_data_csums(fs_info, start, len, csums, csum_bitmap); + if (ret < 0) + goto out; + + for (u32 i = 0; i < len / sectorsize; i++) { + if (!test_bit(i, csum_bitmap)) { + scrub_ctx->csum_discards++; + continue; + } + + data_csum = ~(u32)0; + data_csum = btrfs_csum_data(buf + i * sectorsize, data_csum, + sectorsize); + btrfs_csum_final(data_csum, (u8 *)&data_csum); + + if (memcmp(&data_csum, (char *)csums + i * sizeof(data_csum), + sizeof(data_csum))) { + error("data at bytenr %llu mirror %d csum mismatch, have 0x%08x expect 0x%08x", + start + cur, mirror, data_csum, + *(u32 *)((char *)csums + i * sizeof(data_csum))); + err = 1; + scrub_ctx->csum_errors++; + continue; + } + scrub_ctx->data_bytes_scrubbed += sectorsize; + } +out: + if (!data) + free(buf); + free(csums); + free(csum_bitmap); + + if (!ret && err) + return -EIO; + return ret; +} -- 2.12.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
