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Commit 2dabb324 authored by Chandan Rajendra's avatar Chandan Rajendra Committed by David Sterba
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Btrfs: Direct I/O read: Work on sectorsized blocks 



The direct I/O read's endio and corresponding repair functions work on
page sized blocks. This commit adds the ability for direct I/O read to work on
subpagesized blocks.

Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent c40a3d38

fs/btrfs/inode.c

+75 −23
Original line number Diff line number Diff line
@@ -7751,9 +7751,9 @@ static int btrfs_check_dio_repairable(struct inode *inode, 
}



static int dio_read_error(struct inode *inode, struct bio *failed_bio,

			  struct page *page, u64 start, u64 end,

			  int failed_mirror, bio_end_io_t *repair_endio,

			  void *repair_arg)

			struct page *page, unsigned int pgoff,

			u64 start, u64 end, int failed_mirror,

			bio_end_io_t *repair_endio, void *repair_arg)

{

	struct io_failure_record *failrec;

	struct bio *bio;
@@ -7774,7 +7774,9 @@ static int dio_read_error(struct inode *inode, struct bio *failed_bio, 
		return -EIO;

	}



	if (failed_bio->bi_vcnt > 1)

	if ((failed_bio->bi_vcnt > 1)

		|| (failed_bio->bi_io_vec->bv_len

			> BTRFS_I(inode)->root->sectorsize))

		read_mode = READ_SYNC | REQ_FAILFAST_DEV;

	else

		read_mode = READ_SYNC;
@@ -7782,7 +7784,7 @@ static int dio_read_error(struct inode *inode, struct bio *failed_bio, 
	isector = start - btrfs_io_bio(failed_bio)->logical;

	isector >>= inode->i_sb->s_blocksize_bits;

	bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,

				      0, isector, repair_endio, repair_arg);

				pgoff, isector, repair_endio, repair_arg);

	if (!bio) {

		free_io_failure(inode, failrec);

		return -EIO;
@@ -7812,12 +7814,17 @@ struct btrfs_retry_complete { 
static void btrfs_retry_endio_nocsum(struct bio *bio)

{

	struct btrfs_retry_complete *done = bio->bi_private;

	struct inode *inode;

	struct bio_vec *bvec;

	int i;



	if (bio->bi_error)

		goto end;



	ASSERT(bio->bi_vcnt == 1);

	inode = bio->bi_io_vec->bv_page->mapping->host;

	ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);



	done->uptodate = 1;

	bio_for_each_segment_all(bvec, bio, i)

		clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
@@ -7829,23 +7836,33 @@ static void btrfs_retry_endio_nocsum(struct bio *bio) 
static int __btrfs_correct_data_nocsum(struct inode *inode,

				       struct btrfs_io_bio *io_bio)

{

	struct btrfs_fs_info *fs_info;

	struct bio_vec *bvec;

	struct btrfs_retry_complete done;

	u64 start;

	unsigned int pgoff;

	u32 sectorsize;

	int nr_sectors;

	int i;

	int ret;



	fs_info = BTRFS_I(inode)->root->fs_info;

	sectorsize = BTRFS_I(inode)->root->sectorsize;



	start = io_bio->logical;

	done.inode = inode;



	bio_for_each_segment_all(bvec, &io_bio->bio, i) {

try_again:

		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);

		pgoff = bvec->bv_offset;



next_block_or_try_again:

		done.uptodate = 0;

		done.start = start;

		init_completion(&done.done);



		ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,

				     start + bvec->bv_len - 1,

		ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,

				pgoff, start, start + sectorsize - 1,

				io_bio->mirror_num,

				btrfs_retry_endio_nocsum, &done);

		if (ret)
@@ -7855,10 +7872,15 @@ static int __btrfs_correct_data_nocsum(struct inode *inode, 


		if (!done.uptodate) {

			/* We might have another mirror, so try again */

			goto try_again;

			goto next_block_or_try_again;

		}



		start += bvec->bv_len;

		start += sectorsize;



		if (nr_sectors--) {

			pgoff += sectorsize;

			goto next_block_or_try_again;

		}

	}



	return 0;
@@ -7868,7 +7890,9 @@ static void btrfs_retry_endio(struct bio *bio) 
{

	struct btrfs_retry_complete *done = bio->bi_private;

	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);

	struct inode *inode;

	struct bio_vec *bvec;

	u64 start;

	int uptodate;

	int ret;

	int i;
@@ -7877,13 +7901,20 @@ static void btrfs_retry_endio(struct bio *bio) 
		goto end;



	uptodate = 1;



	start = done->start;



	ASSERT(bio->bi_vcnt == 1);

	inode = bio->bi_io_vec->bv_page->mapping->host;

	ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);



	bio_for_each_segment_all(bvec, bio, i) {

		ret = __readpage_endio_check(done->inode, io_bio, i,

					     bvec->bv_page, 0,

					bvec->bv_page, bvec->bv_offset,

					done->start, bvec->bv_len);

		if (!ret)

			clean_io_failure(done->inode, done->start,

					 bvec->bv_page, 0);

					bvec->bv_page, bvec->bv_offset);

		else

			uptodate = 0;

	}
@@ -7897,20 +7928,34 @@ static void btrfs_retry_endio(struct bio *bio) 
static int __btrfs_subio_endio_read(struct inode *inode,

				    struct btrfs_io_bio *io_bio, int err)

{

	struct btrfs_fs_info *fs_info;

	struct bio_vec *bvec;

	struct btrfs_retry_complete done;

	u64 start;

	u64 offset = 0;

	u32 sectorsize;

	int nr_sectors;

	unsigned int pgoff;

	int csum_pos;

	int i;

	int ret;



	fs_info = BTRFS_I(inode)->root->fs_info;

	sectorsize = BTRFS_I(inode)->root->sectorsize;



	err = 0;

	start = io_bio->logical;

	done.inode = inode;



	bio_for_each_segment_all(bvec, &io_bio->bio, i) {

		ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,

					     0, start, bvec->bv_len);

		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);



		pgoff = bvec->bv_offset;

next_block:

		csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);

		ret = __readpage_endio_check(inode, io_bio, csum_pos,

					bvec->bv_page, pgoff, start,

					sectorsize);

		if (likely(!ret))

			goto next;

try_again:
@@ -7918,8 +7963,8 @@ static int __btrfs_subio_endio_read(struct inode *inode, 
		done.start = start;

		init_completion(&done.done);



		ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,

				     start + bvec->bv_len - 1,

		ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,

				pgoff, start, start + sectorsize - 1,

				io_bio->mirror_num,

				btrfs_retry_endio, &done);

		if (ret) {
@@ -7934,8 +7979,15 @@ static int __btrfs_subio_endio_read(struct inode *inode, 
			goto try_again;

		}

next:

		offset += bvec->bv_len;

		start += bvec->bv_len;

		offset += sectorsize;

		start += sectorsize;



		ASSERT(nr_sectors);



		if (--nr_sectors) {

			pgoff += sectorsize;

			goto next_block;

		}

	}



	return err;