On 02/27/2018 06:31 PM, Qu Wenruo wrote:
On 2018年02月27日 18:01, Su Yue wrote:
On 02/27/2018 05:12 PM, Qu Wenruo wrote:
Original --check-data-csum option will skip the extra copy if the first
copy matches csum.
Since offline scrub (with recoverability report) is still out-of-tree, at
least enhance --check-data-csum option to handle multiple copies.
Signed-off-by: Qu Wenruo <w...@suse.com>
---
check/main.c | 65
++++++++++++++++++++++++++++++------------------------------
1 file changed, 32 insertions(+), 33 deletions(-)
diff --git a/check/main.c b/check/main.c
index 97baae583f04..f25fdc765d63 100644
--- a/check/main.c
+++ b/check/main.c
@@ -5381,42 +5381,37 @@ static int check_extent_csums(struct
btrfs_root *root, u64 bytenr,
if (!data)
return -ENOMEM;
+ num_copies = btrfs_num_copies(root->fs_info, bytenr, num_bytes);
while (offset < num_bytes) {
- mirror = 0;
-again:
- read_len = num_bytes - offset;
- /* read as much space once a time */
- ret = read_extent_data(fs_info, 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((char *)data + tmp,
- csum, fs_info->sectorsize);
- btrfs_csum_final(csum, (u8 *)&csum);
-
- csum_offset = leaf_offset +
- tmp / fs_info->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",
+ for (mirror = 1; mirror <= num_copies; mirror++) {
Got your point.
But what confuses me is that why mirror starts from 1 here.
The mirror influences btrfs_map_block() which is not related
to this patch though.
mirror number has different meanings in fact.
For 0, it means try to read *ANY* valid copy, it can be the copy of a
duplication, or even rebuilt data from RAID5/6.
For 1, it means the fist copy. Either the only copy of
SINGLE/RAID0/RAID5/6, or the first copy of RAID1/10.
For 2, it means the 2nd copy, it can be real copy for RAID1/RAID10, or
rebuilt data from RAID5/6.
And in fact Liu Bo is adding new copy numbers for RAID5/6 to allow us to
specify how to build the missing data for RAID6.
So here starting from mirror 1 is the correct behavior.
Make sense.
Thanks for your explanation！
Su
Thanks,
Qu
Thanks,
Su
+ read_len = num_bytes - offset;
+ /* read as much space once a time */
+ ret = read_extent_data(fs_info, 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((char *)data + tmp,
+ csum, fs_info->sectorsize);
+ btrfs_csum_final(csum, (u8 *)&csum);
+
+ csum_offset = leaf_offset +
+ tmp / fs_info->sectorsize * csum_size;
+ read_extent_buffer(eb, (char *)&csum_expected,
+ csum_offset, csum_size);
+ 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,
- bytenr, num_bytes);
- if (mirror < num_copies - 1) {
- mirror += 1;
- goto again;
- }
+ data_checked += fs_info->sectorsize;
}
- data_checked += fs_info->sectorsize;
}
offset += read_len;
}
@@ -5624,7 +5619,11 @@ static int check_csums(struct btrfs_root *root)
leaf_offset = btrfs_item_ptr_offset(leaf, path.slots[0]);
ret = check_extent_csums(root, key.offset, data_len,
leaf_offset, leaf);
- if (ret)
+ /*
+ * Only break for fatal errors, if mismatch is found,
+ * continue checking until all extents are checked.
+ */
+ if (ret < 0)
break;
skip_csum_check:
if (!num_bytes) {
--
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