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ore: Must support none-PAGE-aligned IO

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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: Boaz Harrosh <bharrosh@panasas.com>
This commit is contained in:
Boaz Harrosh 2011-12-28 19:21:45 +02:00
parent 361aba569f
commit 724577ca35
1 changed files with 60 additions and 12 deletions
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72
fs/exofs/ore_raid.c
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@ -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);