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Commit ac6b53b6 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarYuri Tikhonov <yur@emcraft.com>
Signed-off-by: default avatarIlya Yanok <yanok@emcraft.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 4e7d2c0a

drivers/md/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -124,6 +124,8 @@ config MD_RAID456 
	select MD_RAID6_PQ

	select ASYNC_MEMCPY

	select ASYNC_XOR

	select ASYNC_PQ

	select ASYNC_RAID6_RECOV

	---help---

	  A RAID-5 set of N drives with a capacity of C MB per drive provides

	  the capacity of C * (N - 1) MB, and protects against a failure

drivers/md/raid5.c

+292 −30
Original line number Diff line number Diff line
@@ -636,15 +636,16 @@ static void mark_target_uptodate(struct stripe_head *sh, int target) 
	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 @@ ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu) 
	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 @@ ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu) 
	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 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) 
	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);

	}
@@ -793,7 +989,7 @@ static void ops_complete_postxor(void *stripe_head_ref) 
}



static void

ops_run_postxor(struct stripe_head *sh, struct raid5_percpu *percpu,

ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,

		     struct dma_async_tx_descriptor *tx)

{

	int disks = sh->disks;
@@ -837,7 +1033,7 @@ ops_run_postxor(struct stripe_head *sh, struct raid5_percpu *percpu, 


	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 @@ ops_run_postxor(struct stripe_head *sh, struct raid5_percpu *percpu, 
		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 @@ static void ops_complete_check(void *stripe_head_ref) 
	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 @@ static void ops_run_check(struct stripe_head *sh, struct raid5_percpu *percpu) 
	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 @@ static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request) 
	}



	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {

		if (level < 6)

			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))

		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 @@ static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request) 
		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 @@ schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s, 
		} 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 @@ schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s, 
		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 @@ static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s, 
			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 @@ static void handle_stripe_dirtying5(raid5_conf_t *conf, 
	 */

	/* 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 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh, 
				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 @@ static bool handle_stripe5(struct stripe_head *sh) 
		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);

drivers/md/raid5.h

+5 −3
Original line number Diff line number Diff line
@@ -176,7 +176,9 @@ 
 */

enum check_states {

	check_state_idle = 0,

	check_state_run, /* parity check */

	check_state_run, /* xor parity check */

	check_state_run_q, /* q-parity check */

	check_state_run_pq, /* pq dual parity check */

	check_state_check_result,

	check_state_compute_run, /* parity repair */

	check_state_compute_result,
@@ -216,7 +218,7 @@ struct stripe_head { 
	 * @target - STRIPE_OP_COMPUTE_BLK target

	 */

	struct stripe_operations {

		int		     target;

		int 		     target, target2;

		enum sum_check_flags zero_sum_result;

	} ops;

	struct r5dev {
@@ -299,7 +301,7 @@ struct r6_state { 
#define STRIPE_OP_COMPUTE_BLK	1

#define STRIPE_OP_PREXOR	2

#define STRIPE_OP_BIODRAIN	3

#define STRIPE_OP_POSTXOR	4

#define STRIPE_OP_RECONSTRUCT	4

#define STRIPE_OP_CHECK	5



/*