Commit 72d7df4c authored by Bryan Gurney's avatar Bryan Gurney Committed by Mike Snitzer
Browse files

dm dust: add limited write failure mode 



Add a limited write failure mode which allows a write to a block to fail
a specified amount of times, prior to remapping.  The "addbadblock"
message is extended to allow specifying the limited number of times a
write fails.

Example: add bad block on block 60, with 5 write failures:
  dmsetup message 0 dust1 addbadblock 60 5

The write failure counter will be printed for newly added bad blocks.

Signed-off-by: default avatarBryan Gurney <bgurney@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent cc7a7fb3

drivers/md/dm-dust.c

+46 −7
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
struct badblock {

	struct rb_node node;

	sector_t bb;

	unsigned char wr_fail_cnt;

};



struct dust_device {
@@ -101,7 +102,8 @@ static int dust_remove_block(struct dust_device *dd, unsigned long long block) 
	return 0;

}



static int dust_add_block(struct dust_device *dd, unsigned long long block)

static int dust_add_block(struct dust_device *dd, unsigned long long block,

			  unsigned char wr_fail_cnt)

{

	struct badblock *bblock;

	unsigned long flags;
@@ -115,6 +117,7 @@ static int dust_add_block(struct dust_device *dd, unsigned long long block) 


	spin_lock_irqsave(&dd->dust_lock, flags);

	bblock->bb = block;

	bblock->wr_fail_cnt = wr_fail_cnt;

	if (!dust_rb_insert(&dd->badblocklist, bblock)) {

		if (!dd->quiet_mode) {

			DMERR("%s: block %llu already in badblocklist",
@@ -126,8 +129,10 @@ static int dust_add_block(struct dust_device *dd, unsigned long long block) 
	}



	dd->badblock_count++;

	if (!dd->quiet_mode)

		DMINFO("%s: badblock added at block %llu", __func__, block);

	if (!dd->quiet_mode) {

		DMINFO("%s: badblock added at block %llu with write fail count %hhu",

		       __func__, block, wr_fail_cnt);

	}

	spin_unlock_irqrestore(&dd->dust_lock, flags);



	return 0;
@@ -175,10 +180,15 @@ static int dust_map_read(struct dust_device *dd, sector_t thisblock, 
	return r;

}



static void __dust_map_write(struct dust_device *dd, sector_t thisblock)

static int __dust_map_write(struct dust_device *dd, sector_t thisblock)

{

	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);



	if (bblk && bblk->wr_fail_cnt > 0) {

		bblk->wr_fail_cnt--;

		return DM_MAPIO_KILL;

	}



	if (bblk) {

		rb_erase(&bblk->node, &dd->badblocklist);

		dd->badblock_count--;
@@ -189,21 +199,24 @@ static void __dust_map_write(struct dust_device *dd, sector_t thisblock) 
			       (unsigned long long)thisblock);

		}

	}



	return DM_MAPIO_REMAPPED;

}



static int dust_map_write(struct dust_device *dd, sector_t thisblock,

			  bool fail_read_on_bb)

{

	unsigned long flags;

	int ret = DM_MAPIO_REMAPPED;



	if (fail_read_on_bb) {

		thisblock >>= dd->sect_per_block_shift;

		spin_lock_irqsave(&dd->dust_lock, flags);

		__dust_map_write(dd, thisblock);

		ret = __dust_map_write(dd, thisblock);

		spin_unlock_irqrestore(&dd->dust_lock, flags);

	}



	return DM_MAPIO_REMAPPED;

	return ret;

}



static int dust_map(struct dm_target *ti, struct bio *bio)
@@ -377,6 +390,8 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, 
	bool invalid_msg = false;

	int r = -EINVAL;

	unsigned long long tmp, block;

	unsigned char wr_fail_cnt;

	unsigned int tmp_ui;

	unsigned long flags;

	char dummy;
@@ -422,7 +437,7 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, 
		}



		if (!strcasecmp(argv[0], "addbadblock"))

			r = dust_add_block(dd, block);

			r = dust_add_block(dd, block, 0);

		else if (!strcasecmp(argv[0], "removebadblock"))

			r = dust_remove_block(dd, block);

		else if (!strcasecmp(argv[0], "queryblock"))
@@ -430,6 +445,30 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, 
		else

			invalid_msg = true;



	} else if (argc == 3) {

		if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)

			return r;



		if (sscanf(argv[2], "%u%c", &tmp_ui, &dummy) != 1)

			return r;



		block = tmp;

		if (tmp_ui > 255) {

			DMERR("selected write fail count out of range");

			return r;

		}

		wr_fail_cnt = tmp_ui;

		sector_div(size, dd->sect_per_block);

		if (block > size) {

			DMERR("selected block value out of range");

			return r;

		}



		if (!strcasecmp(argv[0], "addbadblock"))

			r = dust_add_block(dd, block, wr_fail_cnt);

		else

			invalid_msg = true;



	} else

		DMERR("invalid number of arguments '%d'", argc);

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