Commit 483cbbed authored by Alexei Naberezhnov's avatar Alexei Naberezhnov Committed by Song Liu
Browse files

md/raid5: fix 'out of memory' during raid cache recovery 



This fixes the case when md array assembly fails because of raid cache recovery
unable to allocate a stripe, despite attempts to replay stripes and increase
cache size. This happens because stripes released by r5c_recovery_replay_stripes
and raid5_set_cache_size don't become available for allocation immediately.
Released stripes first are placed on conf->released_stripes list and require
md thread to merge them on conf->inactive_list before they can be allocated.

Patch allows final allocation attempt during cache recovery to wait for
new stripes to become availabe for allocation.

Cc: linux-raid@vger.kernel.org
Cc: Shaohua Li <shli@kernel.org>
Cc: linux-stable <stable@vger.kernel.org> # 4.10+
Fixes: b4c625c6 ("md/r5cache: r5cache recovery: part 1")
Signed-off-by: default avatarAlexei Naberezhnov <anaberezhnov@fb.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent f17b5f06

drivers/md/raid5-cache.c

+22 −11
Original line number Original line Diff line number Diff line
@@ -1935,12 +1935,14 @@ out: 
}

}





static struct stripe_head *

static struct stripe_head *

r5c_recovery_alloc_stripe(struct r5conf *conf,

r5c_recovery_alloc_stripe(

			  sector_t stripe_sect)

		struct r5conf *conf,

		sector_t stripe_sect,

		int noblock)

{

{

	struct stripe_head *sh;

	struct stripe_head *sh;





	sh = raid5_get_active_stripe(conf, stripe_sect, 0, 1, 0);

	sh = raid5_get_active_stripe(conf, stripe_sect, 0, noblock, 0);

	if (!sh)

	if (!sh)

		return NULL;  /* no more stripe available */

		return NULL;  /* no more stripe available */
@@ -2150,7 +2152,7 @@ r5c_recovery_analyze_meta_block(struct r5l_log *log, 
						stripe_sect);

						stripe_sect);





		if (!sh) {

		if (!sh) {

			sh = r5c_recovery_alloc_stripe(conf, stripe_sect);

			sh = r5c_recovery_alloc_stripe(conf, stripe_sect, 1);

			/*

			/*

			 * cannot get stripe from raid5_get_active_stripe

			 * cannot get stripe from raid5_get_active_stripe

			 * try replay some stripes

			 * try replay some stripes
@@ -2159,16 +2161,25 @@ r5c_recovery_analyze_meta_block(struct r5l_log *log, 
				r5c_recovery_replay_stripes(

				r5c_recovery_replay_stripes(

					cached_stripe_list, ctx);

					cached_stripe_list, ctx);

				sh = r5c_recovery_alloc_stripe(

				sh = r5c_recovery_alloc_stripe(

					conf, stripe_sect);

					conf, stripe_sect, 1);

			}

			}

			if (!sh) {

			if (!sh) {

				int new_size = conf->min_nr_stripes * 2;

				pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n",

				pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n",

					mdname(mddev),

					mdname(mddev),

					conf->min_nr_stripes * 2);

					new_size);

				raid5_set_cache_size(mddev,

				ret = raid5_set_cache_size(mddev, new_size);

						     conf->min_nr_stripes * 2);

				if (conf->min_nr_stripes <= new_size / 2) {

				sh = r5c_recovery_alloc_stripe(conf,

					pr_err("md/raid:%s: Cannot increase cache size, ret=%d, new_size=%d, min_nr_stripes=%d, max_nr_stripes=%d\n",

							       stripe_sect);

						mdname(mddev),

						ret,

						new_size,

						conf->min_nr_stripes,

						conf->max_nr_stripes);

					return -ENOMEM;

				}

				sh = r5c_recovery_alloc_stripe(

					conf, stripe_sect, 0);

			}

			}

			if (!sh) {

			if (!sh) {

				pr_err("md/raid:%s: Cannot get enough stripes due to memory pressure. Recovery failed.\n",

				pr_err("md/raid:%s: Cannot get enough stripes due to memory pressure. Recovery failed.\n",

drivers/md/raid5.c

+6 −2
Original line number Original line Diff line number Diff line
@@ -6369,6 +6369,7 @@ raid5_show_stripe_cache_size(struct mddev *mddev, char *page) 
int

int

raid5_set_cache_size(struct mddev *mddev, int size)

raid5_set_cache_size(struct mddev *mddev, int size)

{

{

	int result = 0;

	struct r5conf *conf = mddev->private;

	struct r5conf *conf = mddev->private;





	if (size <= 16 || size > 32768)

	if (size <= 16 || size > 32768)
@@ -6385,11 +6386,14 @@ raid5_set_cache_size(struct mddev *mddev, int size) 




	mutex_lock(&conf->cache_size_mutex);

	mutex_lock(&conf->cache_size_mutex);

	while (size > conf->max_nr_stripes)

	while (size > conf->max_nr_stripes)

		if (!grow_one_stripe(conf, GFP_KERNEL))

		if (!grow_one_stripe(conf, GFP_KERNEL)) {

			conf->min_nr_stripes = conf->max_nr_stripes;

			result = -ENOMEM;

			break;

			break;

		}

	mutex_unlock(&conf->cache_size_mutex);

	mutex_unlock(&conf->cache_size_mutex);





	return 0;

	return result;

}

}

EXPORT_SYMBOL(raid5_set_cache_size);

EXPORT_SYMBOL(raid5_set_cache_size);

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