md/raid5: finish support for DDF/raid6
DDF requires RAID6 calculations over different devices in a different
order.
For md/raid6, we calculate over just the data devices, starting
immediately after the 'Q' block.
For ddf/raid6 we calculate over all devices, using zeros in place of
the P and Q blocks.
This requires unfortunately complex loops...
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c1d94ed..edbc80c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -136,6 +136,10 @@
/* Find first data disk in a raid6 stripe */
static inline int raid6_d0(struct stripe_head *sh)
{
+ if (sh->ddf_layout)
+ /* ddf always start from first device */
+ return 0;
+ /* md starts just after Q block */
if (sh->qd_idx == sh->disks - 1)
return 0;
else
@@ -152,13 +156,15 @@
* 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
* is raid_disks-1. This help does that mapping.
*/
-static int raid6_idx_to_slot(int idx, struct stripe_head *sh, int *count)
+static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
+ int *count, int syndrome_disks)
{
int slot;
+
if (idx == sh->pd_idx)
- return sh->disks - 2;
+ return syndrome_disks;
if (idx == sh->qd_idx)
- return sh->disks - 1;
+ return syndrome_disks + 1;
slot = (*count)++;
return slot;
}
@@ -1267,6 +1273,7 @@
unsigned long chunk_number;
unsigned int chunk_offset;
int pd_idx, qd_idx;
+ int ddf_layout = 0;
sector_t new_sector;
int sectors_per_chunk = conf->chunk_size >> 9;
int raid_disks = previous ? conf->previous_raid_disks
@@ -1386,6 +1393,7 @@
qd_idx = 0;
} else if (*dd_idx >= pd_idx)
(*dd_idx) += 2; /* D D P Q D */
+ ddf_layout = 1;
break;
case ALGORITHM_ROTATING_N_RESTART:
@@ -1400,6 +1408,7 @@
qd_idx = 0;
} else if (*dd_idx >= pd_idx)
(*dd_idx) += 2; /* D D P Q D */
+ ddf_layout = 1;
break;
case ALGORITHM_ROTATING_N_CONTINUE:
@@ -1407,6 +1416,7 @@
pd_idx = raid_disks - 1 - (stripe % raid_disks);
qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
+ ddf_layout = 1;
break;
case ALGORITHM_LEFT_ASYMMETRIC_6:
@@ -1454,6 +1464,7 @@
if (sh) {
sh->pd_idx = pd_idx;
sh->qd_idx = qd_idx;
+ sh->ddf_layout = ddf_layout;
}
/*
* Finally, compute the new sector number
@@ -1642,9 +1653,10 @@
{
raid5_conf_t *conf = sh->raid_conf;
int i, pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
+ int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
struct bio *chosen;
/**** FIX THIS: This could be very bad if disks is close to 256 ****/
- void *ptrs[disks];
+ void *ptrs[syndrome_disks+2];
pd_idx = sh->pd_idx;
qd_idx = sh->qd_idx;
@@ -1687,23 +1699,28 @@
}
/* Note that unlike RAID-5, the ordering of the disks matters greatly.*/
- /* FIX: Is this ordering of drives even remotely optimal? */
+
+ for (i = 0; i < disks; i++)
+ ptrs[i] = (void *)raid6_empty_zero_page;
+
count = 0;
i = d0_idx;
do {
- int slot = raid6_idx_to_slot(i, sh, &count);
+ int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
ptrs[slot] = page_address(sh->dev[i].page);
- if (slot < sh->disks - 2 &&
+ if (slot < syndrome_disks &&
!test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
printk(KERN_ERR "block %d/%d not uptodate "
"on parity calc\n", i, count);
BUG();
}
+
i = raid6_next_disk(i, disks);
} while (i != d0_idx);
- BUG_ON(count+2 != disks);
+ BUG_ON(count != syndrome_disks);
- raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs);
+ raid6_call.gen_syndrome(syndrome_disks+2, STRIPE_SIZE, ptrs);
switch(method) {
case RECONSTRUCT_WRITE:
@@ -1761,24 +1778,28 @@
static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
{
int i, count, disks = sh->disks;
+ int syndrome_disks = sh->ddf_layout ? disks : disks-2;
int d0_idx = raid6_d0(sh);
int faila = -1, failb = -1;
/**** FIX THIS: This could be very bad if disks is close to 256 ****/
- void *ptrs[disks];
+ void *ptrs[syndrome_disks+2];
+ for (i = 0; i < disks ; i++)
+ ptrs[i] = (void *)raid6_empty_zero_page;
count = 0;
i = d0_idx;
do {
- int slot;
- slot = raid6_idx_to_slot(i, sh, &count);
+ int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
ptrs[slot] = page_address(sh->dev[i].page);
+
if (i == dd_idx1)
faila = slot;
if (i == dd_idx2)
failb = slot;
i = raid6_next_disk(i, disks);
} while (i != d0_idx);
- BUG_ON(count+2 != disks);
+ BUG_ON(count != syndrome_disks);
BUG_ON(faila == failb);
if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
@@ -1787,9 +1808,9 @@
(unsigned long long)sh->sector, dd_idx1, dd_idx2,
faila, failb);
- if ( failb == disks-1 ) {
+ if (failb == syndrome_disks+1) {
/* Q disk is one of the missing disks */
- if ( faila == disks-2 ) {
+ if (faila == syndrome_disks) {
/* Missing P+Q, just recompute */
compute_parity6(sh, UPDATE_PARITY);
return;
@@ -1804,12 +1825,13 @@
}
/* We're missing D+P or D+D; */
- if (failb == disks-2) {
+ if (failb == syndrome_disks) {
/* We're missing D+P. */
- raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
+ raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE, faila, ptrs);
} else {
/* We're missing D+D. */
- raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs);
+ raid6_2data_recov(syndrome_disks+2, STRIPE_SIZE, faila, failb,
+ ptrs);
}
/* Both the above update both missing blocks */