Commit ce5d36aa authored by Boaz Harrosh's avatar Boaz Harrosh
Browse files

ore: Support for raid 6 



This simple patch adds support for raid6 to the ORE.
Most operations and calculations where already for the general
case. Only things left:
* call async_gen_syndrome() in the case of raid6
  (NOTE that the raid6 math is the one supported by the Linux Kernel
   see: crypto/async_tx/async_pq.c)
* call _ore_add_parity_unit() twice with only last call generating
  the redundancy pages.

* Fix couple BUGS in old code
  a. In reads when parity==2 it can happen that per_dev->length=0
     but per_dev->offset was set and adjusted by _ore_add_sg_seg().
     Don't let it be overwritten.
  b. The all 'cur_comp > starting_dev' thing to determine if:
       "per_dev->offset is in the current stripe number or the
       next one."
     Was a complete raid5/4 accident. When parity==2 this is not
     at all true usually. All we need to do is increment si->ob_offset
     once we pass by the first parity device.
     (This also greatly simplifies the code, amen)
  c. Calculation of si->dev rotation can overflow when parity==2.

* Then last enable raid6 in ore_verify_layout()

I want to deeply thank Daniel Gryniewicz who found first all the
bugs in the old raid code, and inspired these patches:
	Inspired-by Daniel Gryniewicz <dang@linuxbox.com>

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
parent 455682ce

fs/exofs/Kconfig.ore

+2 −0
Original line number Diff line number Diff line
@@ -9,4 +9,6 @@ config ORE 
	tristate

	depends on EXOFS_FS || PNFS_OBJLAYOUT

	select ASYNC_XOR

	select RAID6_PQ

	select ASYNC_PQ

	default SCSI_OSD_ULD

fs/exofs/ore.c

+52 −23
Original line number Diff line number Diff line
@@ -58,9 +58,12 @@ int ore_verify_layout(unsigned total_comps, struct ore_layout *layout) 
		layout->parity = 1;

		break;

	case PNFS_OSD_RAID_PQ:

		layout->parity = 2;

		break;

	case PNFS_OSD_RAID_4:

	default:

		ORE_ERR("Only RAID_0/5 for now\n");

		ORE_ERR("Only RAID_0/5/6 for now received-enum=%d\n",

			layout->raid_algorithm);

		return -EINVAL;

	}

	if (0 != (layout->stripe_unit & ~PAGE_MASK)) {
@@ -112,6 +115,8 @@ int ore_verify_layout(unsigned total_comps, struct ore_layout *layout) 
		layout->max_io_length /= stripe_length;

		layout->max_io_length *= stripe_length;

	}

	ORE_DBGMSG("max_io_length=0x%lx\n", layout->max_io_length);



	return 0;

}

EXPORT_SYMBOL(ore_verify_layout);
@@ -561,7 +566,8 @@ void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset, 


		si->par_dev = (group_width + group_width - parity - RxP) %

			      group_width + first_dev;

		si->dev = (group_width + C - RxP) % group_width + first_dev;

		si->dev = (group_width + group_width + C - RxP) %

			  group_width + first_dev;

		si->bytes_in_stripe = U;

		si->first_stripe_start = M * S + G * T + N * U;

	} else {
@@ -651,6 +657,43 @@ out: /* we fail the complete unit on an error eg don't advance 
	return ret;

}



static int _add_parity_units(struct ore_io_state *ios,

			     struct ore_striping_info *si,

			     unsigned dev, unsigned first_dev,

			     unsigned mirrors_p1, unsigned devs_in_group,

			     unsigned cur_len)

{

	unsigned do_parity;

	int ret = 0;



	for (do_parity = ios->layout->parity; do_parity; --do_parity) {

		struct ore_per_dev_state *per_dev;



		per_dev = &ios->per_dev[dev - first_dev];

		if (!per_dev->length && !per_dev->offset) {

			/* Only/always the parity unit of the first

			 * stripe will be empty. So this is a chance to

			 * initialize the per_dev info.

			 */

			per_dev->dev = dev;

			per_dev->offset = si->obj_offset - si->unit_off;

		}



		ret = _ore_add_parity_unit(ios, si, per_dev, cur_len,

					   do_parity == 1);

		if (unlikely(ret))

				break;



		if (do_parity != 1) {

			dev = ((dev + mirrors_p1) % devs_in_group) + first_dev;

			si->cur_comp = (si->cur_comp + 1) %

						       ios->layout->group_width;

		}

	}



	return ret;

}



static int _prepare_for_striping(struct ore_io_state *ios)

{

	struct ore_striping_info *si = &ios->si;
@@ -660,7 +703,6 @@ static int _prepare_for_striping(struct ore_io_state *ios) 
	unsigned devs_in_group = group_width * mirrors_p1;

	unsigned dev = si->dev;

	unsigned first_dev = dev - (dev % devs_in_group);

	unsigned dev_order;

	unsigned cur_pg = ios->pages_consumed;

	u64 length = ios->length;

	int ret = 0;
@@ -672,14 +714,13 @@ static int _prepare_for_striping(struct ore_io_state *ios) 


	BUG_ON(length > si->length);



	dev_order = si->cur_comp;



	while (length) {

		struct ore_per_dev_state *per_dev =

						&ios->per_dev[dev - first_dev];

		unsigned cur_len, page_off = 0;



		if (!per_dev->length) {

		if (!per_dev->length && !per_dev->offset) {

			/* First time initialize the per_dev info. */

			per_dev->dev = dev;

			if (dev == si->dev) {

				WARN_ON(dev == si->par_dev);
@@ -688,13 +729,7 @@ static int _prepare_for_striping(struct ore_io_state *ios) 
				page_off = si->unit_off & ~PAGE_MASK;

				BUG_ON(page_off && (page_off != ios->pgbase));

			} else {

				if (si->cur_comp > dev_order)

					per_dev->offset =

						si->obj_offset - si->unit_off;

				else /* si->cur_comp < dev_order */

					per_dev->offset =

						si->obj_offset + stripe_unit -

								   si->unit_off;

				per_dev->offset = si->obj_offset - si->unit_off;

				cur_len = stripe_unit;

			}

		} else {
@@ -721,20 +756,12 @@ static int _prepare_for_striping(struct ore_io_state *ios) 
				/* If last stripe operate on parity comp */

				si->cur_comp = group_width - ios->layout->parity;

			}

			per_dev = &ios->per_dev[dev - first_dev];

			if (!per_dev->length) {

				/* Only/always the parity unit of the first

				 * stripe will be empty. So this is a chance to

				 * initialize the per_dev info.

				 */

				per_dev->dev = dev;

				per_dev->offset = si->obj_offset - si->unit_off;

			}



			/* In writes cur_len just means if it's the

			 * last one. See _ore_add_parity_unit.

			 */

			ret = _ore_add_parity_unit(ios, si, per_dev,

			ret = _add_parity_units(ios, si, dev, first_dev,

						mirrors_p1, devs_in_group,

						ios->sp2d ? length : cur_len);

			if (unlikely(ret))

					goto out;
@@ -746,6 +773,8 @@ static int _prepare_for_striping(struct ore_io_state *ios) 
			/* Next stripe, start fresh */

			si->cur_comp = 0;

			si->cur_pg = 0;

			si->obj_offset += cur_len;

			si->unit_off = 0;

		}

	}

out:

fs/exofs/ore_raid.c

+24 −13
Original line number Diff line number Diff line
@@ -218,20 +218,28 @@ static unsigned _sp2d_max_pg(struct __stripe_pages_2d *sp2d) 
static void _gen_xor_unit(struct __stripe_pages_2d *sp2d)

{

	unsigned p;

	unsigned tx_flags = ASYNC_TX_ACK;



	if (sp2d->parity == 1)

		tx_flags |= ASYNC_TX_XOR_ZERO_DST;



	for (p = 0; p < sp2d->pages_in_unit; p++) {

		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];



		if (!_1ps->write_count)

			continue;



		init_async_submit(&_1ps->submit,

			ASYNC_TX_XOR_ZERO_DST | ASYNC_TX_ACK,

		init_async_submit(&_1ps->submit, tx_flags,

			NULL, NULL, NULL, (addr_conv_t *)_1ps->scribble);



		/* TODO: raid6 */

		_1ps->tx = async_xor(_1ps->pages[sp2d->data_devs], _1ps->pages,

				     0, sp2d->data_devs, PAGE_SIZE,

				     &_1ps->submit);

		if (sp2d->parity == 1)

			_1ps->tx = async_xor(_1ps->pages[sp2d->data_devs],

						_1ps->pages, 0, sp2d->data_devs,

						PAGE_SIZE, &_1ps->submit);

		else /* parity == 2 */

			_1ps->tx = async_gen_syndrome(_1ps->pages, 0,

						sp2d->data_devs + sp2d->parity,

						PAGE_SIZE, &_1ps->submit);

	}



	for (p = 0; p < sp2d->pages_in_unit; p++) {
@@ -616,7 +624,7 @@ static int _read_4_write_execute(struct ore_io_state *ios) 
int _ore_add_parity_unit(struct ore_io_state *ios,

			    struct ore_striping_info *si,

			    struct ore_per_dev_state *per_dev,

			    unsigned cur_len)

			    unsigned cur_len, bool do_xor)

{

	if (ios->reading) {

		if (per_dev->cur_sg >= ios->sgs_per_dev) {
@@ -641,9 +649,11 @@ int _ore_add_parity_unit(struct ore_io_state *ios, 
			/* If first stripe, Read in all read4write pages

			 * (if needed) before we calculate the first parity.

			 */

			if (do_xor)

				_read_4_write_first_stripe(ios);

		}

		if (!cur_len) /* If last stripe r4w pages of last stripe */

		if (!cur_len && do_xor)

			/* If last stripe r4w pages of last stripe */

			_read_4_write_last_stripe(ios);

		_read_4_write_execute(ios);
@@ -655,7 +665,7 @@ int _ore_add_parity_unit(struct ore_io_state *ios, 
			++(ios->cur_par_page);

		}



		BUG_ON(si->cur_comp != sp2d->data_devs);

		BUG_ON(si->cur_comp < sp2d->data_devs);

		BUG_ON(si->cur_pg + num_pages > sp2d->pages_in_unit);



		ret = _ore_add_stripe_unit(ios,  &array_start, 0, pages,
@@ -663,10 +673,11 @@ int _ore_add_parity_unit(struct ore_io_state *ios, 
		if (unlikely(ret))

			return ret;



		/* TODO: raid6 if (last_parity_dev) */

		if (do_xor) {

			_gen_xor_unit(sp2d);

			_sp2d_reset(sp2d, ios->r4w, ios->private);

		}

	}

	return 0;

}

fs/exofs/ore_raid.h

+2 −1
Original line number Diff line number Diff line
@@ -38,7 +38,8 @@ void _ore_free_raid_stuff(struct ore_io_state *ios); 
void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,

		 bool not_last);

int _ore_add_parity_unit(struct ore_io_state *ios, struct ore_striping_info *si,

		     struct ore_per_dev_state *per_dev, unsigned cur_len);

		     struct ore_per_dev_state *per_dev, unsigned cur_len,

		     bool do_xor);

void _ore_add_stripe_page(struct __stripe_pages_2d *sp2d,

		       struct ore_striping_info *si, struct page *page);

static inline void _add_stripe_page(struct __stripe_pages_2d *sp2d,

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