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Commit ccfcc3c1 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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[PATCH] md: Core of raid5 resize process 



This patch provides the core of the resize/expand process.

sync_request notices if a 'reshape' is happening and acts accordingly.

It allocated new stripe_heads for the next chunk-wide-stripe in the target
geometry, marking them STRIPE_EXPANDING.

Then it finds which stripe heads in the old geometry can provide data needed
by these and marks them STRIPE_EXPAND_SOURCE.  This causes stripe_handle to
read all blocks on those stripes.

Once all blocks on a STRIPE_EXPAND_SOURCE stripe_head are read, any that are
needed are copied into the corresponding STRIPE_EXPANDING stripe_head.  Once a
STRIPE_EXPANDING stripe_head is full, it is marks STRIPE_EXPAND_READY and then
is written out and released.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7ecaa1e6

drivers/md/md.c

+11 −3
Original line number Diff line number Diff line
@@ -2165,7 +2165,9 @@ action_show(mddev_t *mddev, char *page) 
	char *type = "idle";

	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||

	    test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) {

		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {

		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))

			type = "reshape";

		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {

			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))

				type = "resync";

			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
@@ -4088,8 +4090,10 @@ static void status_resync(struct seq_file *seq, mddev_t * mddev) 
		seq_printf(seq, "] ");

	}

	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",

		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?

		    "reshape" :

		      (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?

		       "resync" : "recovery"),

		       "resync" : "recovery")),

		      per_milli/10, per_milli % 10,

		   (unsigned long long) resync,

		   (unsigned long long) max_blocks);
@@ -4543,7 +4547,9 @@ static void md_do_sync(mddev_t *mddev) 
		 */

		max_sectors = mddev->resync_max_sectors;

		mddev->resync_mismatches = 0;

	} else

	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))

		max_sectors = mddev->size << 1;

	else

		/* recovery follows the physical size of devices */

		max_sectors = mddev->size << 1;
@@ -4679,6 +4685,8 @@ static void md_do_sync(mddev_t *mddev) 
	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);



	if (!test_bit(MD_RECOVERY_ERR, &mddev->recovery) &&

	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&

	    !test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&

	    mddev->curr_resync > 2 &&

	    mddev->curr_resync >= mddev->recovery_cp) {

		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {

drivers/md/raid5.c

+163 −22
Original line number Diff line number Diff line
@@ -93,14 +93,14 @@ static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) 
				if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)

					md_wakeup_thread(conf->mddev->thread);

			}

			list_add_tail(&sh->lru, &conf->inactive_list);

			atomic_dec(&conf->active_stripes);

			if (!conf->inactive_blocked ||

			    atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))

			if (!test_bit(STRIPE_EXPANDING, &sh->state)) {

				list_add_tail(&sh->lru, &conf->inactive_list);

				wake_up(&conf->wait_for_stripe);

			}

		}

	}

}

static void release_stripe(struct stripe_head *sh)

{

	raid5_conf_t *conf = sh->raid_conf;
@@ -273,8 +273,7 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector 
			} else {

				if (!test_bit(STRIPE_HANDLE, &sh->state))

					atomic_inc(&conf->active_stripes);

				if (list_empty(&sh->lru))

					BUG();

				if (!list_empty(&sh->lru))

					list_del_init(&sh->lru);

			}

		}
@@ -1035,6 +1034,18 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in 
	return 0;

}



static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)

{

	int sectors_per_chunk = conf->chunk_size >> 9;

	sector_t x = stripe;

	int pd_idx, dd_idx;

	int chunk_offset = sector_div(x, sectors_per_chunk);

	stripe = x;

	raid5_compute_sector(stripe*(disks-1)*sectors_per_chunk

			     + chunk_offset, disks, disks-1, &dd_idx, &pd_idx, conf);

	return pd_idx;

}





/*

 * handle_stripe - do things to a stripe.
@@ -1061,7 +1072,7 @@ static void handle_stripe(struct stripe_head *sh) 
	struct bio *return_bi= NULL;

	struct bio *bi;

	int i;

	int syncing;

	int syncing, expanding, expanded;

	int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;

	int non_overwrite = 0;

	int failed_num=0;
@@ -1076,6 +1087,8 @@ static void handle_stripe(struct stripe_head *sh) 
	clear_bit(STRIPE_DELAYED, &sh->state);



	syncing = test_bit(STRIPE_SYNCING, &sh->state);

	expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);

	expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);

	/* Now to look around and see what can be done */



	rcu_read_lock();
@@ -1268,13 +1281,14 @@ static void handle_stripe(struct stripe_head *sh) 
	 * parity, or to satisfy requests

	 * or to load a block that is being partially written.

	 */

	if (to_read || non_overwrite || (syncing && (uptodate < disks))) {

	if (to_read || non_overwrite || (syncing && (uptodate < disks)) || expanding) {

		for (i=disks; i--;) {

			dev = &sh->dev[i];

			if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&

			    (dev->toread ||

			     (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||

			     syncing ||

			     expanding ||

			     (failed && (sh->dev[failed_num].toread ||

					 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))

				    )
@@ -1464,10 +1478,73 @@ static void handle_stripe(struct stripe_head *sh) 
			set_bit(R5_Wantwrite, &dev->flags);

			set_bit(R5_ReWrite, &dev->flags);

			set_bit(R5_LOCKED, &dev->flags);

			locked++;

		} else {

			/* let's read it back */

			set_bit(R5_Wantread, &dev->flags);

			set_bit(R5_LOCKED, &dev->flags);

			locked++;

		}

	}



	if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {

		/* Need to write out all blocks after computing parity */

		sh->disks = conf->raid_disks;

		sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);

		compute_parity(sh, RECONSTRUCT_WRITE);

		for (i= conf->raid_disks; i--;) {

			set_bit(R5_LOCKED, &sh->dev[i].flags);

			locked++;

			set_bit(R5_Wantwrite, &sh->dev[i].flags);

		}

		clear_bit(STRIPE_EXPANDING, &sh->state);

	} else if (expanded) {

		clear_bit(STRIPE_EXPAND_READY, &sh->state);

		wake_up(&conf->wait_for_overlap);

		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);

	}



	if (expanding && locked == 0) {

		/* We have read all the blocks in this stripe and now we need to

		 * copy some of them into a target stripe for expand.

		 */

		clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);

		for (i=0; i< sh->disks; i++)

			if (i != sh->pd_idx) {

				int dd_idx, pd_idx, j;

				struct stripe_head *sh2;



				sector_t bn = compute_blocknr(sh, i);

				sector_t s = raid5_compute_sector(bn, conf->raid_disks,

								  conf->raid_disks-1,

								  &dd_idx, &pd_idx, conf);

				sh2 = get_active_stripe(conf, s, conf->raid_disks, pd_idx, 1);

				if (sh2 == NULL)

					/* so far only the early blocks of this stripe

					 * have been requested.  When later blocks

					 * get requested, we will try again

					 */

					continue;

				if(!test_bit(STRIPE_EXPANDING, &sh2->state) ||

				   test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {

					/* must have already done this block */

					release_stripe(sh2);

					continue;

				}

				memcpy(page_address(sh2->dev[dd_idx].page),

				       page_address(sh->dev[i].page),

				       STRIPE_SIZE);

				set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);

				set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);

				for (j=0; j<conf->raid_disks; j++)

					if (j != sh2->pd_idx &&

					    !test_bit(R5_Expanded, &sh2->dev[j].flags))

						break;

				if (j == conf->raid_disks) {

					set_bit(STRIPE_EXPAND_READY, &sh2->state);

					set_bit(STRIPE_HANDLE, &sh2->state);

				}

				release_stripe(sh2);

			}

	}
@@ -1509,7 +1586,7 @@ static void handle_stripe(struct stripe_head *sh) 
		rcu_read_unlock();

 

		if (rdev) {

			if (syncing)

			if (syncing || expanding || expanded)

				md_sync_acct(rdev->bdev, STRIPE_SECTORS);



			bi->bi_bdev = rdev->bdev;
@@ -1757,12 +1834,8 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 
{

	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;

	struct stripe_head *sh;

	int sectors_per_chunk = conf->chunk_size >> 9;

	sector_t x;

	unsigned long stripe;

	int chunk_offset;

	int dd_idx, pd_idx;

	sector_t first_sector;

	int pd_idx;

	sector_t first_sector, last_sector;

	int raid_disks = conf->raid_disks;

	int data_disks = raid_disks-1;

	sector_t max_sector = mddev->size << 1;
@@ -1781,6 +1854,80 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 


		return 0;

	}



	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {

		/* reshaping is quite different to recovery/resync so it is

		 * handled quite separately ... here.

		 *

		 * On each call to sync_request, we gather one chunk worth of

		 * destination stripes and flag them as expanding.

		 * Then we find all the source stripes and request reads.

		 * As the reads complete, handle_stripe will copy the data

		 * into the destination stripe and release that stripe.

		 */

		int i;

		int dd_idx;

		for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {

			int j;

			int skipped = 0;

			pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);

			sh = get_active_stripe(conf, sector_nr+i,

					       conf->raid_disks, pd_idx, 0);

			set_bit(STRIPE_EXPANDING, &sh->state);

			/* If any of this stripe is beyond the end of the old

			 * array, then we need to zero those blocks

			 */

			for (j=sh->disks; j--;) {

				sector_t s;

				if (j == sh->pd_idx)

					continue;

				s = compute_blocknr(sh, j);

				if (s < (mddev->array_size<<1)) {

					skipped = 1;

					continue;

				}

				memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);

				set_bit(R5_Expanded, &sh->dev[j].flags);

				set_bit(R5_UPTODATE, &sh->dev[j].flags);

			}

			if (!skipped) {

				set_bit(STRIPE_EXPAND_READY, &sh->state);

				set_bit(STRIPE_HANDLE, &sh->state);

			}

			release_stripe(sh);

		}

		spin_lock_irq(&conf->device_lock);

		conf->expand_progress = (sector_nr + i)*(conf->raid_disks-1);

		spin_unlock_irq(&conf->device_lock);

		/* Ok, those stripe are ready. We can start scheduling

		 * reads on the source stripes.

		 * The source stripes are determined by mapping the first and last

		 * block on the destination stripes.

		 */

		raid_disks = conf->previous_raid_disks;

		data_disks = raid_disks - 1;

		first_sector =

			raid5_compute_sector(sector_nr*(conf->raid_disks-1),

					     raid_disks, data_disks,

					     &dd_idx, &pd_idx, conf);

		last_sector =

			raid5_compute_sector((sector_nr+conf->chunk_size/512)

					       *(conf->raid_disks-1) -1,

					     raid_disks, data_disks,

					     &dd_idx, &pd_idx, conf);

		if (last_sector >= (mddev->size<<1))

			last_sector = (mddev->size<<1)-1;

		while (first_sector <= last_sector) {

			pd_idx = stripe_to_pdidx(first_sector, conf, conf->previous_raid_disks);

			sh = get_active_stripe(conf, first_sector,

					       conf->previous_raid_disks, pd_idx, 0);

			set_bit(STRIPE_EXPAND_SOURCE, &sh->state);

			set_bit(STRIPE_HANDLE, &sh->state);

			release_stripe(sh);

			first_sector += STRIPE_SECTORS;

		}

		return conf->chunk_size>>9;

	}

	/* if there is 1 or more failed drives and we are trying

	 * to resync, then assert that we are finished, because there is

	 * nothing we can do.
@@ -1799,13 +1946,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 
		return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */

	}



	x = sector_nr;

	chunk_offset = sector_div(x, sectors_per_chunk);

	stripe = x;

	BUG_ON(x != stripe);



	first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk

		+ chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);

	pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);

	sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);

	if (sh == NULL) {

		sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);

include/linux/raid/md_k.h

+4 −0
Original line number Diff line number Diff line
@@ -157,6 +157,9 @@ struct mddev_s 
	 * DONE:     thread is done and is waiting to be reaped

	 * REQUEST:  user-space has requested a sync (used with SYNC)

	 * CHECK:    user-space request for for check-only, no repair

	 * RESHAPE:  A reshape is happening

	 *

	 * If neither SYNC or RESHAPE are set, then it is a recovery.

	 */

#define	MD_RECOVERY_RUNNING	0

#define	MD_RECOVERY_SYNC	1
@@ -166,6 +169,7 @@ struct mddev_s 
#define	MD_RECOVERY_NEEDED	5

#define	MD_RECOVERY_REQUESTED	6

#define	MD_RECOVERY_CHECK	7

#define MD_RECOVERY_RESHAPE	8

	unsigned long			recovery;



	int				in_sync;	/* know to not need resync */

include/linux/raid/raid5.h

+3 −1
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ struct stripe_head { 
#define	R5_ReadError	8	/* seen a read error here recently */

#define	R5_ReWrite	9	/* have tried to over-write the readerror */



#define	R5_Expanded	10	/* This block now has post-expand data */

/*

 * Write method

 */
@@ -176,7 +177,8 @@ struct stripe_head { 
#define	STRIPE_DEGRADED		7

#define	STRIPE_BIT_DELAY	8

#define	STRIPE_EXPANDING	9



#define	STRIPE_EXPAND_SOURCE	10

#define	STRIPE_EXPAND_READY	11

/*

 * Plugging:

 *