Commit 3a4d4eb3 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Jens Axboe
Browse files

drbd: prepare for new striped layout of activity log 



Introduce two new on-disk meta data fields: al_stripes and al_stripe_size_4k
The intended use case is activity log on RAID 0 or similar.
Logically consecutive transactions will advance their on-disk position
by al_stripe_size_4k 4kB (transaction sized) blocks.

Right now, these are still asserted to be the backward compatible
values al_stripes = 1, al_stripe_size_4k = 8 (which amounts to 32kB).

Also introduce a caching member for meta_dev_idx in the in-core
structure: even though it is initially passed in in the rcu-protected
disk_conf structure, it cannot change without a detach/attach cycle.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ae8bf312

drivers/block/drbd/drbd_actlog.c

+3 −3
Original line number Diff line number Diff line
@@ -353,11 +353,11 @@ static unsigned int rs_extent_to_bm_page(unsigned int rs_enr) 


static sector_t al_tr_number_to_on_disk_sector(struct drbd_conf *mdev)

{

	const unsigned int stripes = 1;

	const unsigned int stripe_size_4kB = MD_32kB_SECT/MD_4kB_SECT;

	const unsigned int stripes = mdev->ldev->md.al_stripes;

	const unsigned int stripe_size_4kB = mdev->ldev->md.al_stripe_size_4k;



	/* transaction number, modulo on-disk ring buffer wrap around */

	unsigned int t = mdev->al_tr_number % (stripe_size_4kB * stripes);

	unsigned int t = mdev->al_tr_number % (mdev->ldev->md.al_size_4k);



	/* ... to aligned 4k on disk block */

	t = ((t % stripes) * stripe_size_4kB) + t/stripes;

drivers/block/drbd/drbd_int.h

+20 −26
Original line number Diff line number Diff line
@@ -755,6 +755,14 @@ struct drbd_md { 


	s32 al_offset;	/* signed relative sector offset to activity log */

	s32 bm_offset;	/* signed relative sector offset to bitmap */



	/* cached value of bdev->disk_conf->meta_dev_idx (see below) */

	s32 meta_dev_idx;



	/* see al_tr_number_to_on_disk_sector() */

	u32 al_stripes;

	u32 al_stripe_size_4k;

	u32 al_size_4k; /* cached product of the above */

};



struct drbd_backing_dev {
@@ -1862,38 +1870,24 @@ static inline sector_t drbd_get_max_capacity(struct drbd_backing_dev *bdev) 
}



/**

 * drbd_md_ss__() - Return the sector number of our meta data super block

 * @mdev:	DRBD device.

 * drbd_md_ss() - Return the sector number of our meta data super block

 * @bdev:	Meta data block device.

 */

static inline sector_t drbd_md_ss__(struct drbd_conf *mdev,

				    struct drbd_backing_dev *bdev)

static inline sector_t drbd_md_ss(struct drbd_backing_dev *bdev)

{

	int meta_dev_idx;

	const int meta_dev_idx = bdev->md.meta_dev_idx;



	rcu_read_lock();

	meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;

	rcu_read_unlock();



	switch (meta_dev_idx) {

	default: /* external, some index; this is the old fixed size layout */

		return MD_128MB_SECT * meta_dev_idx;

	case DRBD_MD_INDEX_INTERNAL:

		/* with drbd08, internal meta data is always "flexible" */

	case DRBD_MD_INDEX_FLEX_INT:

		if (!bdev->backing_bdev) {

			if (__ratelimit(&drbd_ratelimit_state)) {

				dev_err(DEV, "bdev->backing_bdev==NULL\n");

				dump_stack();

			}

	if (meta_dev_idx == DRBD_MD_INDEX_FLEX_EXT)

		return 0;

		}

		/* sizeof(struct md_on_disk_07) == 4k



	/* Since drbd08, internal meta data is always "flexible".

	 * position: last 4k aligned block of 4k size */

	if (meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||

	    meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)

		return (drbd_get_capacity(bdev->backing_bdev) & ~7ULL) - 8;

	case DRBD_MD_INDEX_FLEX_EXT:

		return 0;

	}



	/* external, some index; this is the old fixed size layout */

	return MD_128MB_SECT * bdev->md.meta_dev_idx;

}



static inline void

drivers/block/drbd/drbd_main.c

+69 −8
Original line number Diff line number Diff line
@@ -2850,7 +2850,11 @@ struct meta_data_on_disk { 
	u32 bm_bytes_per_bit;  /* BM_BLOCK_SIZE */

	u32 la_peer_max_bio_size;   /* last peer max_bio_size */



	u8 reserved_u8[4096 - (7*8 + 8*4)];

	/* see al_tr_number_to_on_disk_sector() */

	u32 al_stripes;

	u32 al_stripe_size_4k;



	u8 reserved_u8[4096 - (7*8 + 10*4)];

} __packed;



/**
@@ -2898,7 +2902,10 @@ void drbd_md_sync(struct drbd_conf *mdev) 
	buffer->bm_offset = cpu_to_be32(mdev->ldev->md.bm_offset);

	buffer->la_peer_max_bio_size = cpu_to_be32(mdev->peer_max_bio_size);



	D_ASSERT(drbd_md_ss__(mdev, mdev->ldev) == mdev->ldev->md.md_offset);

	buffer->al_stripes = cpu_to_be32(mdev->ldev->md.al_stripes);

	buffer->al_stripe_size_4k = cpu_to_be32(mdev->ldev->md.al_stripe_size_4k);



	D_ASSERT(drbd_md_ss(mdev->ldev) == mdev->ldev->md.md_offset);

	sector = mdev->ldev->md.md_offset;



	if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
@@ -2916,13 +2923,60 @@ out: 
	put_ldev(mdev);

}



static int check_activity_log_stripe_size(struct drbd_conf *mdev,

		struct meta_data_on_disk *on_disk,

		struct drbd_md *in_core)

{

	u32 al_stripes = be32_to_cpu(on_disk->al_stripes);

	u32 al_stripe_size_4k = be32_to_cpu(on_disk->al_stripe_size_4k);

	u64 al_size_4k;



	/* both not set: default to old fixed size activity log */

	if (al_stripes == 0 && al_stripe_size_4k == 0) {

		al_stripes = 1;

		al_stripe_size_4k = MD_32kB_SECT/8;

	}



	/* some paranoia plausibility checks */



	/* we need both values to be set */

	if (al_stripes == 0 || al_stripe_size_4k == 0)

		goto err;



	al_size_4k = (u64)al_stripes * al_stripe_size_4k;



	/* Upper limit of activity log area, to avoid potential overflow

	 * problems in al_tr_number_to_on_disk_sector(). As right now, more

	 * than 72 * 4k blocks total only increases the amount of history,

	 * limiting this arbitrarily to 16 GB is not a real limitation ;-)  */

	if (al_size_4k > (16 * 1024 * 1024/4))

		goto err;



	/* Lower limit: we need at least 8 transaction slots (32kB)

	 * to not break existing setups */

	if (al_size_4k < MD_32kB_SECT/8)

		goto err;



	in_core->al_stripe_size_4k = al_stripe_size_4k;

	in_core->al_stripes = al_stripes;

	in_core->al_size_4k = al_size_4k;



	return 0;

err:

	dev_err(DEV, "invalid activity log striping: al_stripes=%u, al_stripe_size_4k=%u\n",

			al_stripes, al_stripe_size_4k);

	return -EINVAL;

}



/**

 * drbd_md_read() - Reads in the meta data super block

 * @mdev:	DRBD device.

 * @bdev:	Device from which the meta data should be read in.

 *

 * Return 0 (NO_ERROR) on success, and an enum drbd_ret_code in case

 * Return NO_ERROR on success, and an enum drbd_ret_code in case

 * something goes wrong.

 *

 * Called exactly once during drbd_adm_attach()

 */

int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)

{
@@ -2937,6 +2991,10 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
	if (!buffer)

		goto out;



	/* First, figure out where our meta data superblock is located. */

	bdev->md.meta_dev_idx = bdev->disk_conf->meta_dev_idx;

	bdev->md.md_offset = drbd_md_ss(bdev);



	if (drbd_md_sync_page_io(mdev, bdev, bdev->md.md_offset, READ)) {

		/* NOTE: can't do normal error processing here as this is

		   called BEFORE disk is attached */
@@ -2954,40 +3012,43 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev) 
		rv = ERR_MD_UNCLEAN;

		goto err;

	}



	rv = ERR_MD_INVALID;

	if (magic != DRBD_MD_MAGIC_08) {

		if (magic == DRBD_MD_MAGIC_07)

			dev_err(DEV, "Found old (0.7) meta data magic. Did you \"drbdadm create-md\"?\n");

		else

			dev_err(DEV, "Meta data magic not found. Did you \"drbdadm create-md\"?\n");

		rv = ERR_MD_INVALID;

		goto err;

	}



	if (check_activity_log_stripe_size(mdev, buffer, &bdev->md))

		goto err;



	if (be32_to_cpu(buffer->al_offset) != bdev->md.al_offset) {

		dev_err(DEV, "unexpected al_offset: %d (expected %d)\n",

		    be32_to_cpu(buffer->al_offset), bdev->md.al_offset);

		rv = ERR_MD_INVALID;

		goto err;

	}

	if (be32_to_cpu(buffer->bm_offset) != bdev->md.bm_offset) {

		dev_err(DEV, "unexpected bm_offset: %d (expected %d)\n",

		    be32_to_cpu(buffer->bm_offset), bdev->md.bm_offset);

		rv = ERR_MD_INVALID;

		goto err;

	}

	if (be32_to_cpu(buffer->md_size_sect) != bdev->md.md_size_sect) {

		dev_err(DEV, "unexpected md_size: %u (expected %u)\n",

		    be32_to_cpu(buffer->md_size_sect), bdev->md.md_size_sect);

		rv = ERR_MD_INVALID;

		goto err;

	}



	if (be32_to_cpu(buffer->bm_bytes_per_bit) != BM_BLOCK_SIZE) {

		dev_err(DEV, "unexpected bm_bytes_per_bit: %u (expected %u)\n",

		    be32_to_cpu(buffer->bm_bytes_per_bit), BM_BLOCK_SIZE);

		rv = ERR_MD_INVALID;

		goto err;

	}



	rv = NO_ERROR;



	bdev->md.la_size_sect = be64_to_cpu(buffer->la_size);

	for (i = UI_CURRENT; i < UI_SIZE; i++)

		bdev->md.uuid[i] = be64_to_cpu(buffer->uuid[i]);

drivers/block/drbd/drbd_nl.c

+2 −3
Original line number Diff line number Diff line
@@ -727,24 +727,23 @@ static void drbd_md_set_sector_offsets(struct drbd_conf *mdev, 
	rcu_read_lock();

	meta_dev_idx = rcu_dereference(bdev->disk_conf)->meta_dev_idx;



	bdev->md.md_offset = drbd_md_ss(bdev);



	switch (meta_dev_idx) {

	default:

		/* v07 style fixed size indexed meta data */

		bdev->md.md_size_sect = MD_128MB_SECT;

		bdev->md.md_offset = drbd_md_ss__(mdev, bdev);

		bdev->md.al_offset = MD_4kB_SECT;

		bdev->md.bm_offset = MD_4kB_SECT + al_size_sect;

		break;

	case DRBD_MD_INDEX_FLEX_EXT:

		/* just occupy the full device; unit: sectors */

		bdev->md.md_size_sect = drbd_get_capacity(bdev->md_bdev);

		bdev->md.md_offset = 0;

		bdev->md.al_offset = MD_4kB_SECT;

		bdev->md.bm_offset = MD_4kB_SECT + al_size_sect;

		break;

	case DRBD_MD_INDEX_INTERNAL:

	case DRBD_MD_INDEX_FLEX_INT:

		bdev->md.md_offset = drbd_md_ss__(mdev, bdev);

		/* al size is still fixed */

		bdev->md.al_offset = -al_size_sect;

		/* we need (slightly less than) ~ this much bitmap sectors: */

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