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md/raid1: store behind-write pages in bi_vecs. 

When performing write-behind we allocate pages to store the data
during write.
Previously we just keep a list of pages.  Now we keep a list of
bi_vec which includes offset and size.
This means that the r1bio has complete information to create a new
bio which will be needed for retrying after write errors.

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
This commit is contained in:
NeilBrown 2011-07-28 11:32:10 +10:00
parent 4367af5561
commit 2ca68f5ed7
2 changed files with 18 additions and 17 deletions
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33
drivers/md/raid1.c
View File

@ -327,9 +327,9 @@ static void r1_bio_write_done(r1bio_t *r1_bio)
/* free extra copy of the data pages */
int i = r1_bio->behind_page_count;
while (i--)
safe_put_page(r1_bio->behind_pages[i]);
kfree(r1_bio->behind_pages);
r1_bio->behind_pages = NULL;
safe_put_page(r1_bio->behind_bvecs[i].bv_page);
kfree(r1_bio->behind_bvecs);
r1_bio->behind_bvecs = NULL;
}
/* clear the bitmap if all writes complete successfully */
bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
@ -748,30 +748,31 @@ static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio)
{
int i;
struct bio_vec *bvec;
struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page*),
struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
GFP_NOIO);
if (unlikely(!pages))
if (unlikely(!bvecs))
return;
bio_for_each_segment(bvec, bio, i) {
pages[i] = alloc_page(GFP_NOIO);
if (unlikely(!pages[i]))
bvecs[i] = *bvec;
bvecs[i].bv_page = alloc_page(GFP_NOIO);
if (unlikely(!bvecs[i].bv_page))
goto do_sync_io;
memcpy(kmap(pages[i]) + bvec->bv_offset,
kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
kunmap(pages[i]);
memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
kunmap(bvecs[i].bv_page);
kunmap(bvec->bv_page);
}
r1_bio->behind_pages = pages;
r1_bio->behind_bvecs = bvecs;
r1_bio->behind_page_count = bio->bi_vcnt;
set_bit(R1BIO_BehindIO, &r1_bio->state);
return;
do_sync_io:
for (i = 0; i < bio->bi_vcnt; i++)
if (pages[i])
put_page(pages[i]);
kfree(pages);
if (bvecs[i].bv_page)
put_page(bvecs[i].bv_page);
kfree(bvecs);
PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
}
@ -1058,7 +1059,7 @@ read_again:
&r1_bio->state));
first_clone = 0;
}
if (r1_bio->behind_pages) {
if (r1_bio->behind_bvecs) {
struct bio_vec *bvec;
int j;
@ -1070,7 +1071,7 @@ read_again:
* them all
*/
__bio_for_each_segment(bvec, mbio, j, 0)
bvec->bv_page = r1_bio->behind_pages[j];
bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
atomic_inc(&r1_bio->behind_remaining);
}

2
drivers/md/raid1.h
View File

@ -101,7 +101,7 @@ struct r1bio_s {
struct list_head retry_list;
/* Next two are only valid when R1BIO_BehindIO is set */
struct page **behind_pages;
struct bio_vec *behind_bvecs;
int behind_page_count;
/*
* if the IO is in WRITE direction, then multiple bios are used.