chunk_aligned_read and retry_aligned_read assume that
data_disks == raid_disks - 1
which is not true for raid6.
So when an aligned read request bypasses the cache, we can get the wrong data.
Also change the calculate of raid_disks in compute_blocknr to make it
more obviously correct.
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./drivers/md/raid5.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2006-11-14 10:33:41.000000000 +1100
+++ ./drivers/md/raid5.c 2006-11-14 10:34:17.000000000 +1100
@@ -823,7 +823,8 @@ static sector_t raid5_compute_sector(sec
static sector_t compute_blocknr(struct stripe_head *sh, int i)
{
raid5_conf_t *conf = sh->raid_conf;
- int raid_disks = sh->disks, data_disks = raid_disks - 1;
+ int raid_disks = sh->disks;
+ int data_disks = raid_disks - conf->max_degraded;
sector_t new_sector = sh->sector, check;
int sectors_per_chunk = conf->chunk_size >> 9;
sector_t stripe;
@@ -859,7 +860,6 @@ static sector_t compute_blocknr(struct s
}
break;
case 6:
- data_disks = raid_disks - 2;
if (i == raid6_next_disk(sh->pd_idx, raid_disks))
return 0; /* It is the Q disk */
switch (conf->algorithm) {
@@ -2725,7 +2725,7 @@ static int chunk_aligned_read(request_qu
mddev_t *mddev = q->queuedata;
raid5_conf_t *conf = mddev_to_conf(mddev);
const unsigned int raid_disks = conf->raid_disks;
- const unsigned int data_disks = raid_disks - 1;
+ const unsigned int data_disks = raid_disks - conf->max_degraded;
unsigned int dd_idx, pd_idx;
struct bio* align_bi;
mdk_rdev_t *rdev;
@@ -3145,7 +3145,7 @@ static int retry_aligned_read(raid5_con
logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
sector = raid5_compute_sector( logical_sector,
conf->raid_disks,
- conf->raid_disks-1,
+ conf->raid_disks - conf->max_degraded,
&dd_idx,
&pd_idx,
conf);
-
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