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raid6check: get device ordering correct for syndrome calculation. 

The order of devices used for the syndrome calculation is not
the same as the order of data in the array.
The D block immediately after Q is first, then they continue
cyclicly in raid-disk order, skipping over the P disk if it is seen.

This gets the 'check' right for all layouts other than DDF, which is
quite different.

I haven't confirmed that this does't break repair.


Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2015-07-16 11:25:40 +10:00
parent 0832fb09d9
commit 76cd79d3d1
1 changed files with 15 additions and 6 deletions
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21
raid6check.c
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@ -338,7 +338,7 @@ int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
sighandler_t *sig = xmalloc(3 * sizeof(sighandler_t));
int i, j;
int diskP, diskQ;
int diskP, diskQ, diskD;
int data_disks = raid_disks - 2;
int err = 0;
@ -377,15 +377,24 @@ int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
}
}
diskP = geo_map(-1, start, raid_disks, level, layout);
diskQ = geo_map(-2, start, raid_disks, level, layout);
/* The syndrome-order if disks starts immediately after 'Q',
* but skips P */
diskD = diskQ;
for (i = 0 ; i < data_disks ; i++) {
int disk = geo_map(i, start, raid_disks, level, layout);
blocks[i] = stripes[disk];
block_index_for_slot[disk] = i;
diskD = diskD + 1;
if (diskD > raid_disks)
diskD = 0;
if (diskD == diskP)
diskD += 1;
if (diskD > raid_disks)
diskD = 0;
blocks[i] = stripes[diskD];
block_index_for_slot[diskD] = i;
}
qsyndrome(p, q, (uint8_t**)blocks, data_disks, chunk_size);
diskP = geo_map(-1, start, raid_disks, level, layout);
diskQ = geo_map(-2, start, raid_disks, level, layout);
blocks[data_disks] = stripes[diskP];
block_index_for_slot[diskP] = data_disks;
blocks[data_disks+1] = stripes[diskQ];