Commit 2ca68f5e authored by NeilBrown's avatar NeilBrown
Browse files

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: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarNamhyung Kim <namhyung@gmail.com>
parent 4367af55

drivers/md/raid1.c

+17 −16
Original line number Diff line number Diff line
@@ -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,

		memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,

		       kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);

		kunmap(pages[i]);

		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);

		}

drivers/md/raid1.h

+1 −1
Original line number Diff line number Diff line
@@ -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.

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