Commit b5663ba4 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: simplify interface for init_stripe and get_active_stripe 



Rather than passing 'pd_idx' and 'disks' to these functions, just pass
'previous' which tells whether to use the 'previous' or 'current'
geometry during a reshape, and let init_stripe calculate
disks and pd_idx and anything else it might need.

This is not a substantial simplification and even adds a division.
However we will shortly be adding more complexity to init_stripe
to handle more interesting 'reshape' activities, and without this
change, the interface to these functions would get very complex.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent dd8ac336

drivers/md/raid5.c

+22 −21
Original line number Diff line number Diff line
@@ -274,8 +274,9 @@ static int grow_buffers(struct stripe_head *sh, int num) 
}



static void raid5_build_block(struct stripe_head *sh, int i);

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



static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks)

static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)

{

	raid5_conf_t *conf = sh->raid_conf;

	int i;
@@ -290,11 +291,11 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int 


	remove_hash(sh);



	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;

	sh->sector = sector;

	sh->pd_idx = pd_idx;

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

	sh->state = 0;



	sh->disks = disks;



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

		struct r5dev *dev = &sh->dev[i];
@@ -330,10 +331,12 @@ static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, in 
static void unplug_slaves(mddev_t *mddev);

static void raid5_unplug_device(struct request_queue *q);



static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks,

					     int pd_idx, int noblock)

static struct stripe_head *

get_active_stripe(raid5_conf_t *conf, sector_t sector,

		  int previous, int noblock)

{

	struct stripe_head *sh;

	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;



	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
@@ -361,7 +364,7 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector 
					);

				conf->inactive_blocked = 0;

			} else

				init_stripe(sh, sector, pd_idx, disks);

				init_stripe(sh, sector, previous);

		} else {

			if (atomic_read(&sh->count)) {

			  BUG_ON(!list_empty(&sh->lru));
@@ -2479,8 +2482,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, 
						conf->raid_disks -

						conf->max_degraded, &dd_idx,

						&pd_idx, conf);

			sh2 = get_active_stripe(conf, s, conf->raid_disks,

						pd_idx, 1);

			sh2 = get_active_stripe(conf, s, 0, 1);

			if (sh2 == NULL)

				/* so far only the early blocks of this stripe

				 * have been requested.  When later blocks
@@ -3413,8 +3415,10 @@ static int make_request(struct request_queue *q, struct bio * bi) 
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {

		DEFINE_WAIT(w);

		int disks, data_disks;

		int previous;



	retry:

		previous = 0;

		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);

		if (likely(conf->expand_progress == MaxSector))

			disks = conf->raid_disks;
@@ -3429,9 +3433,10 @@ static int make_request(struct request_queue *q, struct bio * bi) 
			 */

			spin_lock_irq(&conf->device_lock);

			disks = conf->raid_disks;

			if (logical_sector >= conf->expand_progress)

			if (logical_sector >= conf->expand_progress) {

				disks = conf->previous_raid_disks;

			else {

				previous = 1;

			} else {

				if (logical_sector >= conf->expand_lo) {

					spin_unlock_irq(&conf->device_lock);

					schedule();
@@ -3448,7 +3453,8 @@ static int make_request(struct request_queue *q, struct bio * bi) 
			(unsigned long long)new_sector, 

			(unsigned long long)logical_sector);



		sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));

		sh = get_active_stripe(conf, new_sector, previous,

				       (bi->bi_rw&RWA_MASK));

		if (sh) {

			if (unlikely(conf->expand_progress != MaxSector)) {

				/* expansion might have moved on while waiting for a
@@ -3582,9 +3588,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped 
	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);

		sh = get_active_stripe(conf, sector_nr+i, 0, 0);

		set_bit(STRIPE_EXPANDING, &sh->state);

		atomic_inc(&conf->reshape_stripes);

		/* If any of this stripe is beyond the end of the old
@@ -3632,10 +3636,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped 
	if (last_sector >= mddev->dev_sectors)

		last_sector = mddev->dev_sectors - 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);

		sh = get_active_stripe(conf, first_sector, 1, 0);

		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);

		set_bit(STRIPE_HANDLE, &sh->state);

		release_stripe(sh);
@@ -3725,9 +3726,9 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski 
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);



	pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);

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

	sh = get_active_stripe(conf, sector_nr, 0, 1);

	if (sh == NULL) {

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

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

		/* make sure we don't swamp the stripe cache if someone else

		 * is trying to get access

		 */
@@ -3793,7 +3794,7 @@ static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) 
			/* already done this stripe */

			continue;



		sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1);

		sh = get_active_stripe(conf, sector, 0, 1);



		if (!sh) {

			/* failed to get a stripe - must wait */

CRA Git | Maintained and supported by SUSTech CRA and CCSE