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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 */ /* free extra copy of the data pages */
int i = r1_bio->behind_page_count; int i = r1_bio->behind_page_count;
while (i--) while (i--)
safe_put_page(r1_bio->behind_pages[i]); safe_put_page(r1_bio->behind_bvecs[i].bv_page);
kfree(r1_bio->behind_pages); kfree(r1_bio->behind_bvecs);
r1_bio->behind_pages = NULL; r1_bio->behind_bvecs = NULL;
} }
/* clear the bitmap if all writes complete successfully */ /* clear the bitmap if all writes complete successfully */
bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector, 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; int i;
struct bio_vec *bvec; 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); GFP_NOIO);
if (unlikely(!pages)) if (unlikely(!bvecs))
return; return;
bio_for_each_segment(bvec, bio, i) { bio_for_each_segment(bvec, bio, i) {
pages[i] = alloc_page(GFP_NOIO); bvecs[i] = *bvec;
if (unlikely(!pages[i])) bvecs[i].bv_page = alloc_page(GFP_NOIO);
if (unlikely(!bvecs[i].bv_page))
goto do_sync_io; goto do_sync_io;
memcpy(kmap(pages[i]) + bvec->bv_offset, memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len); kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
kunmap(pages[i]); kunmap(bvecs[i].bv_page);
kunmap(bvec->bv_page); kunmap(bvec->bv_page);
} }
r1_bio->behind_pages = pages; r1_bio->behind_bvecs = bvecs;
r1_bio->behind_page_count = bio->bi_vcnt; r1_bio->behind_page_count = bio->bi_vcnt;
set_bit(R1BIO_BehindIO, &r1_bio->state); set_bit(R1BIO_BehindIO, &r1_bio->state);
return; return;
do_sync_io: do_sync_io:
for (i = 0; i < bio->bi_vcnt; i++) for (i = 0; i < bio->bi_vcnt; i++)
if (pages[i]) if (bvecs[i].bv_page)
put_page(pages[i]); put_page(bvecs[i].bv_page);
kfree(pages); kfree(bvecs);
PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size); PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
} }
@ -1058,7 +1059,7 @@ read_again:
&r1_bio->state)); &r1_bio->state));
first_clone = 0; first_clone = 0;
} }
if (r1_bio->behind_pages) { if (r1_bio->behind_bvecs) {
struct bio_vec *bvec; struct bio_vec *bvec;
int j; int j;
@ -1070,7 +1071,7 @@ read_again:
* them all * them all
*/ */
__bio_for_each_segment(bvec, mbio, j, 0) __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)) if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
atomic_inc(&r1_bio->behind_remaining); 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; struct list_head retry_list;
/* Next two are only valid when R1BIO_BehindIO is set */ /* Next two are only valid when R1BIO_BehindIO is set */
struct page **behind_pages; struct bio_vec *behind_bvecs;
int behind_page_count; int behind_page_count;
/* /*
* if the IO is in WRITE direction, then multiple bios are used. * if the IO is in WRITE direction, then multiple bios are used.