md/raid6: asynchronous raid6 operations
[ Based on an original patch by Yuri Tikhonov ]
The raid_run_ops routine uses the asynchronous offload api and
the stripe_operations member of a stripe_head to carry out xor+pq+copy
operations asynchronously, outside the lock.
The operations performed by RAID-6 are the same as in the RAID-5 case
except for no support of STRIPE_OP_PREXOR operations. All the others
are supported:
STRIPE_OP_BIOFILL
- copy data into request buffers to satisfy a read request
STRIPE_OP_COMPUTE_BLK
- generate missing blocks (1 or 2) in the cache from the other blocks
STRIPE_OP_BIODRAIN
- copy data out of request buffers to satisfy a write request
STRIPE_OP_RECONSTRUCT
- recalculate parity for new data that has entered the cache
STRIPE_OP_CHECK
- verify that the parity is correct
The flow is the same as in the RAID-5 case, and reuses some routines, namely:
1/ ops_complete_postxor (renamed to ops_complete_reconstruct)
2/ ops_complete_compute (updated to set up to 2 targets uptodate)
3/ ops_run_check (renamed to ops_run_check_p for xor parity checks)
[neilb@suse.de: fixes to get it to pass mdadm regression suite]
Reviewed-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e3a2990..e68616e 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -636,15 +636,16 @@
clear_bit(R5_Wantcompute, &tgt->flags);
}
-static void ops_complete_compute5(void *stripe_head_ref)
+static void ops_complete_compute(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
- /* mark the computed target as uptodate */
+ /* mark the computed target(s) as uptodate */
mark_target_uptodate(sh, sh->ops.target);
+ mark_target_uptodate(sh, sh->ops.target2);
clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
if (sh->check_state == check_state_compute_run)
@@ -684,7 +685,7 @@
atomic_inc(&sh->count);
init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
- ops_complete_compute5, sh, to_addr_conv(sh, percpu));
+ ops_complete_compute, sh, to_addr_conv(sh, percpu));
if (unlikely(count == 1))
tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
else
@@ -693,6 +694,197 @@
return tx;
}
+/* set_syndrome_sources - populate source buffers for gen_syndrome
+ * @srcs - (struct page *) array of size sh->disks
+ * @sh - stripe_head to parse
+ *
+ * Populates srcs in proper layout order for the stripe and returns the
+ * 'count' of sources to be used in a call to async_gen_syndrome. The P
+ * destination buffer is recorded in srcs[count] and the Q destination
+ * is recorded in srcs[count+1]].
+ */
+static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
+{
+ int disks = sh->disks;
+ int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
+ int d0_idx = raid6_d0(sh);
+ int count;
+ int i;
+
+ for (i = 0; i < disks; i++)
+ srcs[i] = (void *)raid6_empty_zero_page;
+
+ count = 0;
+ i = d0_idx;
+ do {
+ int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
+ srcs[slot] = sh->dev[i].page;
+ i = raid6_next_disk(i, disks);
+ } while (i != d0_idx);
+ BUG_ON(count != syndrome_disks);
+
+ return count;
+}
+
+static struct dma_async_tx_descriptor *
+ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ int disks = sh->disks;
+ struct page **blocks = percpu->scribble;
+ int target;
+ int qd_idx = sh->qd_idx;
+ struct dma_async_tx_descriptor *tx;
+ struct async_submit_ctl submit;
+ struct r5dev *tgt;
+ struct page *dest;
+ int i;
+ int count;
+
+ if (sh->ops.target < 0)
+ target = sh->ops.target2;
+ else if (sh->ops.target2 < 0)
+ target = sh->ops.target;
+ else
+ /* we should only have one valid target */
+ BUG();
+ BUG_ON(target < 0);
+ pr_debug("%s: stripe %llu block: %d\n",
+ __func__, (unsigned long long)sh->sector, target);
+
+ tgt = &sh->dev[target];
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
+ dest = tgt->page;
+
+ atomic_inc(&sh->count);
+
+ if (target == qd_idx) {
+ count = set_syndrome_sources(blocks, sh);
+ blocks[count] = NULL; /* regenerating p is not necessary */
+ BUG_ON(blocks[count+1] != dest); /* q should already be set */
+ init_async_submit(&submit, 0, NULL, ops_complete_compute, sh,
+ to_addr_conv(sh, percpu));
+ tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+ } else {
+ /* Compute any data- or p-drive using XOR */
+ count = 0;
+ for (i = disks; i-- ; ) {
+ if (i == target || i == qd_idx)
+ continue;
+ blocks[count++] = sh->dev[i].page;
+ }
+
+ init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu));
+ tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
+ }
+
+ return tx;
+}
+
+static struct dma_async_tx_descriptor *
+ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ 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;
+ int target = sh->ops.target;
+ int target2 = sh->ops.target2;
+ struct r5dev *tgt = &sh->dev[target];
+ struct r5dev *tgt2 = &sh->dev[target2];
+ struct dma_async_tx_descriptor *tx;
+ struct page **blocks = percpu->scribble;
+ struct async_submit_ctl submit;
+
+ pr_debug("%s: stripe %llu block1: %d block2: %d\n",
+ __func__, (unsigned long long)sh->sector, target, target2);
+ BUG_ON(target < 0 || target2 < 0);
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
+
+ /* we need to open-code set_syndrome_sources to handle to the
+ * slot number conversion for 'faila' and 'failb'
+ */
+ for (i = 0; i < disks ; i++)
+ blocks[i] = (void *)raid6_empty_zero_page;
+ count = 0;
+ i = d0_idx;
+ do {
+ int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
+ blocks[slot] = sh->dev[i].page;
+
+ if (i == target)
+ faila = slot;
+ if (i == target2)
+ failb = slot;
+ i = raid6_next_disk(i, disks);
+ } while (i != d0_idx);
+ BUG_ON(count != syndrome_disks);
+
+ BUG_ON(faila == failb);
+ if (failb < faila)
+ swap(faila, failb);
+ pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
+ __func__, (unsigned long long)sh->sector, faila, failb);
+
+ atomic_inc(&sh->count);
+
+ if (failb == syndrome_disks+1) {
+ /* Q disk is one of the missing disks */
+ if (faila == syndrome_disks) {
+ /* Missing P+Q, just recompute */
+ init_async_submit(&submit, 0, NULL, ops_complete_compute,
+ sh, to_addr_conv(sh, percpu));
+ return async_gen_syndrome(blocks, 0, count+2,
+ STRIPE_SIZE, &submit);
+ } else {
+ struct page *dest;
+ int data_target;
+ int qd_idx = sh->qd_idx;
+
+ /* Missing D+Q: recompute D from P, then recompute Q */
+ if (target == qd_idx)
+ data_target = target2;
+ else
+ data_target = target;
+
+ count = 0;
+ for (i = disks; i-- ; ) {
+ if (i == data_target || i == qd_idx)
+ continue;
+ blocks[count++] = sh->dev[i].page;
+ }
+ dest = sh->dev[data_target].page;
+ init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
+ NULL, NULL, to_addr_conv(sh, percpu));
+ tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
+ &submit);
+
+ count = set_syndrome_sources(blocks, sh);
+ init_async_submit(&submit, 0, tx, ops_complete_compute,
+ sh, to_addr_conv(sh, percpu));
+ return async_gen_syndrome(blocks, 0, count+2,
+ STRIPE_SIZE, &submit);
+ }
+ }
+
+ init_async_submit(&submit, 0, NULL, ops_complete_compute, sh,
+ to_addr_conv(sh, percpu));
+ if (failb == syndrome_disks) {
+ /* We're missing D+P. */
+ return async_raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE,
+ faila, blocks, &submit);
+ } else {
+ /* We're missing D+D. */
+ return async_raid6_2data_recov(syndrome_disks+2, STRIPE_SIZE,
+ faila, failb, blocks, &submit);
+ }
+}
+
+
static void ops_complete_prexor(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
@@ -765,17 +957,21 @@
return tx;
}
-static void ops_complete_postxor(void *stripe_head_ref)
+static void ops_complete_reconstruct(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
- int disks = sh->disks, i, pd_idx = sh->pd_idx;
+ int disks = sh->disks;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = sh->qd_idx;
+ int i;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if (dev->written || i == pd_idx)
+
+ if (dev->written || i == pd_idx || i == qd_idx)
set_bit(R5_UPTODATE, &dev->flags);
}
@@ -793,8 +989,8 @@
}
static void
-ops_run_postxor(struct stripe_head *sh, struct raid5_percpu *percpu,
- struct dma_async_tx_descriptor *tx)
+ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
struct page **xor_srcs = percpu->scribble;
@@ -837,7 +1033,7 @@
atomic_inc(&sh->count);
- init_async_submit(&submit, flags, tx, ops_complete_postxor, sh,
+ init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
to_addr_conv(sh, percpu));
if (unlikely(count == 1))
tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
@@ -845,6 +1041,25 @@
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
}
+static void
+ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ struct async_submit_ctl submit;
+ struct page **blocks = percpu->scribble;
+ int count;
+
+ pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
+
+ count = set_syndrome_sources(blocks, sh);
+
+ atomic_inc(&sh->count);
+
+ init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
+ sh, to_addr_conv(sh, percpu));
+ async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+}
+
static void ops_complete_check(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
@@ -857,23 +1072,28 @@
release_stripe(sh);
}
-static void ops_run_check(struct stripe_head *sh, struct raid5_percpu *percpu)
+static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
{
int disks = sh->disks;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = sh->qd_idx;
+ struct page *xor_dest;
struct page **xor_srcs = percpu->scribble;
struct dma_async_tx_descriptor *tx;
struct async_submit_ctl submit;
-
- int count = 0, pd_idx = sh->pd_idx, i;
- struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
+ int count;
+ int i;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
+ count = 0;
+ xor_dest = sh->dev[pd_idx].page;
+ xor_srcs[count++] = xor_dest;
for (i = disks; i--; ) {
- struct r5dev *dev = &sh->dev[i];
- if (i != pd_idx)
- xor_srcs[count++] = dev->page;
+ if (i == pd_idx || i == qd_idx)
+ continue;
+ xor_srcs[count++] = sh->dev[i].page;
}
init_async_submit(&submit, 0, NULL, NULL, NULL,
@@ -886,11 +1106,32 @@
tx = async_trigger_callback(&submit);
}
-static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request)
+static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
+{
+ struct page **srcs = percpu->scribble;
+ struct async_submit_ctl submit;
+ int count;
+
+ pr_debug("%s: stripe %llu checkp: %d\n", __func__,
+ (unsigned long long)sh->sector, checkp);
+
+ count = set_syndrome_sources(srcs, sh);
+ if (!checkp)
+ srcs[count] = NULL;
+
+ atomic_inc(&sh->count);
+ init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
+ sh, to_addr_conv(sh, percpu));
+ async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
+ &sh->ops.zero_sum_result, percpu->spare_page, &submit);
+}
+
+static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
{
int overlap_clear = 0, i, disks = sh->disks;
struct dma_async_tx_descriptor *tx = NULL;
raid5_conf_t *conf = sh->raid_conf;
+ int level = conf->level;
struct raid5_percpu *percpu;
unsigned long cpu;
@@ -902,9 +1143,16 @@
}
if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
- tx = ops_run_compute5(sh, percpu);
- /* terminate the chain if postxor is not set to be run */
- if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
+ if (level < 6)
+ tx = ops_run_compute5(sh, percpu);
+ else {
+ if (sh->ops.target2 < 0 || sh->ops.target < 0)
+ tx = ops_run_compute6_1(sh, percpu);
+ else
+ tx = ops_run_compute6_2(sh, percpu);
+ }
+ /* terminate the chain if reconstruct is not set to be run */
+ if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
async_tx_ack(tx);
}
@@ -916,11 +1164,23 @@
overlap_clear++;
}
- if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
- ops_run_postxor(sh, percpu, tx);
+ if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
+ if (level < 6)
+ ops_run_reconstruct5(sh, percpu, tx);
+ else
+ ops_run_reconstruct6(sh, percpu, tx);
+ }
- if (test_bit(STRIPE_OP_CHECK, &ops_request))
- ops_run_check(sh, percpu);
+ if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
+ if (sh->check_state == check_state_run)
+ ops_run_check_p(sh, percpu);
+ else if (sh->check_state == check_state_run_q)
+ ops_run_check_pq(sh, percpu, 0);
+ else if (sh->check_state == check_state_run_pq)
+ ops_run_check_pq(sh, percpu, 1);
+ else
+ BUG();
+ }
if (overlap_clear)
for (i = disks; i--; ) {
@@ -1931,7 +2191,7 @@
} else
sh->reconstruct_state = reconstruct_state_run;
- set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
+ set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
@@ -1954,7 +2214,7 @@
sh->reconstruct_state = reconstruct_state_prexor_drain_run;
set_bit(STRIPE_OP_PREXOR, &s->ops_request);
set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
- set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
+ set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
@@ -2206,9 +2466,10 @@
set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
set_bit(R5_Wantcompute, &dev->flags);
sh->ops.target = disk_idx;
+ sh->ops.target2 = -1;
s->req_compute = 1;
/* Careful: from this point on 'uptodate' is in the eye
- * of raid5_run_ops which services 'compute' operations
+ * of raid_run_ops which services 'compute' operations
* before writes. R5_Wantcompute flags a block that will
* be R5_UPTODATE by the time it is needed for a
* subsequent operation.
@@ -2435,8 +2696,8 @@
*/
/* since handle_stripe can be called at any time we need to handle the
* case where a compute block operation has been submitted and then a
- * subsequent call wants to start a write request. raid5_run_ops only
- * handles the case where compute block and postxor are requested
+ * subsequent call wants to start a write request. raid_run_ops only
+ * handles the case where compute block and reconstruct are requested
* simultaneously. If this is not the case then new writes need to be
* held off until the compute completes.
*/
@@ -2618,6 +2879,7 @@
set_bit(R5_Wantcompute,
&sh->dev[sh->pd_idx].flags);
sh->ops.target = sh->pd_idx;
+ sh->ops.target2 = -1;
s->uptodate++;
}
}
@@ -3067,7 +3329,7 @@
md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
if (s.ops_request)
- raid5_run_ops(sh, s.ops_request);
+ raid_run_ops(sh, s.ops_request);
ops_run_io(sh, &s);