+++ /dev/null
-From 67cc2b8165857ba019920d1f00d64bcc4140075d Mon Sep 17 00:00:00 2001
-From: NeilBrown <neilb@suse.de>
-Date: Tue, 31 Mar 2009 14:39:38 +1100
-Subject: [PATCH] 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>
----
- drivers/md/raid5.c | 58 +++++++++++++++++++++++++++++++--------------
- include/linux/raid/raid5.h | 1
- 2 files changed, 41 insertions(+), 18 deletions(-)
-
---- linux-2.6.27-SLE11_BRANCH.orig/drivers/md/raid5.c
-+++ linux-2.6.27-SLE11_BRANCH/drivers/md/raid5.c
-@@ -138,6 +138,10 @@ static inline void raid5_set_bi_hw_segme
- /* 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
-@@ -154,13 +158,15 @@ static inline int raid6_next_disk(int di
- * 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;
- }
-@@ -1269,6 +1275,7 @@ static sector_t raid5_compute_sector(rai
- 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
-@@ -1388,6 +1395,7 @@ static sector_t raid5_compute_sector(rai
- 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:
-@@ -1402,6 +1410,7 @@ static sector_t raid5_compute_sector(rai
- 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:
-@@ -1409,6 +1418,7 @@ static sector_t raid5_compute_sector(rai
- 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:
-@@ -1456,6 +1466,7 @@ static sector_t raid5_compute_sector(rai
- if (sh) {
- sh->pd_idx = pd_idx;
- sh->qd_idx = qd_idx;
-+ sh->ddf_layout = ddf_layout;
- }
- /*
- * Finally, compute the new sector number
-@@ -1644,9 +1655,10 @@ static void compute_parity6(struct strip
- {
- raid6_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;
-@@ -1689,23 +1701,28 @@ static void compute_parity6(struct strip
- }
-
- /* 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:
-@@ -1763,24 +1780,28 @@ static void compute_block_1(struct strip
- 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; }
-@@ -1789,9 +1810,9 @@ static void compute_block_2(struct strip
- (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;
-@@ -1806,12 +1827,13 @@ static void compute_block_2(struct strip
- }
-
- /* 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 */
---- linux-2.6.27-SLE11_BRANCH.orig/include/linux/raid/raid5.h
-+++ linux-2.6.27-SLE11_BRANCH/include/linux/raid/raid5.h
-@@ -202,6 +202,7 @@ struct stripe_head {
- sector_t sector; /* sector of this row */
- short pd_idx; /* parity disk index */
- short qd_idx; /* 'Q' disk index for raid6 */
-+ short ddf_layout;/* use DDF ordering to calculate Q */
- unsigned long state; /* state flags */
- atomic_t count; /* nr of active thread/requests */
- spinlock_t lock;
projects / people / pmueller / ipfire-2.x.git / blobdiff