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Commit 724577ca authored by Boaz Harrosh's avatar Boaz Harrosh
Browse files

ore: Must support none-PAGE-aligned IO 



NFS might send us offsets that are not PAGE aligned. So
we must read in the reminder of the first/last pages, in cases
we need it for Parity calculations.

We only add an sg segments to read the partial page. But
we don't mark it as read=true because it is a lock-for-write
page.

TODO: In some cases (IO spans a single unit) we can just
adjust the raid_unit offset/length, but this is left for
later Kernels.

[Bug in 3.2.0 Kernel]
CC: Stable Tree <stable@kernel.org>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
parent 361aba56

fs/exofs/ore_raid.c

+60 −12
Original line number Diff line number Diff line
@@ -328,8 +328,8 @@ static int _alloc_read_4_write(struct ore_io_state *ios) 
/* @si contains info of the to-be-inserted page. Update of @si should be

 * maintained by caller. Specificaly si->dev, si->obj_offset, ...

 */

static int _add_to_read_4_write(struct ore_io_state *ios,

				struct ore_striping_info *si, struct page *page)

static int _add_to_r4w(struct ore_io_state *ios, struct ore_striping_info *si,

		       struct page *page, unsigned pg_len)

{

	struct request_queue *q;

	struct ore_per_dev_state *per_dev;
@@ -366,17 +366,60 @@ static int _add_to_read_4_write(struct ore_io_state *ios, 
		_ore_add_sg_seg(per_dev, gap, true);

	}

	q = osd_request_queue(ore_comp_dev(read_ios->oc, per_dev->dev));

	added_len = bio_add_pc_page(q, per_dev->bio, page, PAGE_SIZE, 0);

	if (unlikely(added_len != PAGE_SIZE)) {

	added_len = bio_add_pc_page(q, per_dev->bio, page, pg_len,

				    si->obj_offset % PAGE_SIZE);

	if (unlikely(added_len != pg_len)) {

		ORE_DBGMSG("Failed to bio_add_pc_page bi_vcnt=%d\n",

			      per_dev->bio->bi_vcnt);

		return -ENOMEM;

	}



	per_dev->length += PAGE_SIZE;

	per_dev->length += pg_len;

	return 0;

}



/* read the beginning of an unaligned first page */

static int _add_to_r4w_first_page(struct ore_io_state *ios, struct page *page)

{

	struct ore_striping_info si;

	unsigned pg_len;



	ore_calc_stripe_info(ios->layout, ios->offset, 0, &si);



	pg_len = si.obj_offset % PAGE_SIZE;

	si.obj_offset -= pg_len;



	ORE_DBGMSG("offset=0x%llx len=0x%x index=0x%lx dev=%x\n",

		   _LLU(si.obj_offset), pg_len, page->index, si.dev);



	return _add_to_r4w(ios, &si, page, pg_len);

}



/* read the end of an incomplete last page */

static int _add_to_r4w_last_page(struct ore_io_state *ios, u64 *offset)

{

	struct ore_striping_info si;

	struct page *page;

	unsigned pg_len, p, c;



	ore_calc_stripe_info(ios->layout, *offset, 0, &si);



	p = si.unit_off / PAGE_SIZE;

	c = _dev_order(ios->layout->group_width * ios->layout->mirrors_p1,

		       ios->layout->mirrors_p1, si.par_dev, si.dev);

	page = ios->sp2d->_1p_stripes[p].pages[c];



	pg_len = PAGE_SIZE - (si.unit_off % PAGE_SIZE);

	*offset += pg_len;



	ORE_DBGMSG("p=%d, c=%d next-offset=0x%llx len=0x%x dev=%x par_dev=%d\n",

		   p, c, _LLU(*offset), pg_len, si.dev, si.par_dev);



	BUG_ON(!page);



	return _add_to_r4w(ios, &si, page, pg_len);

}



static void _mark_read4write_pages_uptodate(struct ore_io_state *ios, int ret)

{

	struct bio_vec *bv;
@@ -444,9 +487,13 @@ static int _read_4_write(struct ore_io_state *ios) 
			struct page **pp = &_1ps->pages[c];

			bool uptodate;



			if (*pp)

			if (*pp) {

				if (ios->offset % PAGE_SIZE)

					/* Read the remainder of the page */

					_add_to_r4w_first_page(ios, *pp);

				/* to-be-written pages start here */

				goto read_last_stripe;

			}



			*pp = ios->r4w->get_page(ios->private, offset,

						 &uptodate);
@@ -454,7 +501,7 @@ static int _read_4_write(struct ore_io_state *ios) 
				return -ENOMEM;



			if (!uptodate)

				_add_to_read_4_write(ios, &read_si, *pp);

				_add_to_r4w(ios, &read_si, *pp, PAGE_SIZE);



			/* Mark read-pages to be cache_released */

			_1ps->page_is_read[c] = true;
@@ -465,8 +512,11 @@ static int _read_4_write(struct ore_io_state *ios) 
	}



read_last_stripe:

	offset = ios->offset + (ios->length + PAGE_SIZE - 1) /

				PAGE_SIZE * PAGE_SIZE;

	offset = ios->offset + ios->length;

	if (offset % PAGE_SIZE)

		_add_to_r4w_last_page(ios, &offset);

		/* offset will be aligned to next page */



	last_stripe_end = div_u64(offset + bytes_in_stripe - 1, bytes_in_stripe)

				 * bytes_in_stripe;

	if (offset == last_stripe_end) /* Optimize for the aligned case */
@@ -503,7 +553,7 @@ read_last_stripe: 
			/* Mark read-pages to be cache_released */

			_1ps->page_is_read[c] = true;

			if (!uptodate)

				_add_to_read_4_write(ios, &read_si, page);

				_add_to_r4w(ios, &read_si, page, PAGE_SIZE);

		}



		offset += PAGE_SIZE;
@@ -616,8 +666,6 @@ int _ore_post_alloc_raid_stuff(struct ore_io_state *ios) 
			return -ENOMEM;

		}



		BUG_ON(ios->offset % PAGE_SIZE);



		/* Round io down to last full strip */

		first_stripe = div_u64(ios->offset, stripe_size);

		last_stripe = div_u64(ios->offset + ios->length, stripe_size);