Commit 17347cec authored by Liu Bo's avatar Liu Bo Committed by David Sterba
Browse files

Btrfs: change how we iterate bios in endio 



Since dio submit has used bio_clone_fast, the submitted bio may not have a
reliable bi_vcnt, for the bio vector iterations in checksum related
functions, bio->bi_iter is not modified yet and it's safe to use
bio_for_each_segment, while for those bio vector iterations in dio read's
endio, we now save a copy of bvec_iter in struct btrfs_io_bio when cloning
bios and use the helper __bio_for_each_segment with the saved bvec_iter to
access each bvec.

Also for dio reads which don't get split, we also need to save a copy of
bio iterator in btrfs_bio_clone to let __bio_for_each_segments to access
each bvec in dio read's endio.  Note that it doesn't affect other calls of
btrfs_bio_clone() because they don't need to use this iterator.

Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 725130ba

fs/btrfs/extent_io.c

+2 −0
Original line number Diff line number Diff line
@@ -2700,6 +2700,7 @@ struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask) 
		btrfs_bio->csum = NULL;

		btrfs_bio->csum_allocated = NULL;

		btrfs_bio->end_io = NULL;

		btrfs_bio->iter = bio->bi_iter;

	}

	return new;

}
@@ -2736,6 +2737,7 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig, gfp_t gfp_mask, 
	btrfs_bio->end_io = NULL;



	bio_trim(bio, offset >> 9, size >> 9);

	btrfs_bio->iter = bio->bi_iter;

	return bio;

}

fs/btrfs/file-item.c

+15 −16
Original line number Diff line number Diff line
@@ -164,7 +164,8 @@ static int __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, 
				   u64 logical_offset, u32 *dst, int dio)

{

	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);

	struct bio_vec *bvec;

	struct bio_vec bvec;

	struct bvec_iter iter;

	struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio);

	struct btrfs_csum_item *item = NULL;

	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
@@ -177,7 +178,7 @@ static int __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, 
	u64 page_bytes_left;

	u32 diff;

	int nblocks;

	int count = 0, i;

	int count = 0;

	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);



	path = btrfs_alloc_path();
@@ -206,8 +207,6 @@ static int __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, 
	if (bio->bi_iter.bi_size > PAGE_SIZE * 8)

		path->reada = READA_FORWARD;



	WARN_ON(bio->bi_vcnt <= 0);



	/*

	 * the free space stuff is only read when it hasn't been

	 * updated in the current transaction.  So, we can safely
@@ -223,13 +222,13 @@ static int __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, 
	if (dio)

		offset = logical_offset;



	bio_for_each_segment_all(bvec, bio, i) {

		page_bytes_left = bvec->bv_len;

	bio_for_each_segment(bvec, bio, iter) {

		page_bytes_left = bvec.bv_len;

		if (count)

			goto next;



		if (!dio)

			offset = page_offset(bvec->bv_page) + bvec->bv_offset;

			offset = page_offset(bvec.bv_page) + bvec.bv_offset;

		count = btrfs_find_ordered_sum(inode, offset, disk_bytenr,

					       (u32 *)csum, nblocks);

		if (count)
@@ -440,15 +439,15 @@ int btrfs_csum_one_bio(struct inode *inode, struct bio *bio, 
	struct btrfs_ordered_sum *sums;

	struct btrfs_ordered_extent *ordered = NULL;

	char *data;

	struct bio_vec *bvec;

	struct bvec_iter iter;

	struct bio_vec bvec;

	int index;

	int nr_sectors;

	int i, j;

	unsigned long total_bytes = 0;

	unsigned long this_sum_bytes = 0;

	int i;

	u64 offset;



	WARN_ON(bio->bi_vcnt <= 0);

	sums = kzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),

		       GFP_NOFS);

	if (!sums)
@@ -465,19 +464,19 @@ int btrfs_csum_one_bio(struct inode *inode, struct bio *bio, 
	sums->bytenr = (u64)bio->bi_iter.bi_sector << 9;

	index = 0;



	bio_for_each_segment_all(bvec, bio, j) {

	bio_for_each_segment(bvec, bio, iter) {

		if (!contig)

			offset = page_offset(bvec->bv_page) + bvec->bv_offset;

			offset = page_offset(bvec.bv_page) + bvec.bv_offset;



		if (!ordered) {

			ordered = btrfs_lookup_ordered_extent(inode, offset);

			BUG_ON(!ordered); /* Logic error */

		}



		data = kmap_atomic(bvec->bv_page);

		data = kmap_atomic(bvec.bv_page);



		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,

						 bvec->bv_len + fs_info->sectorsize

						 bvec.bv_len + fs_info->sectorsize

						 - 1);



		for (i = 0; i < nr_sectors; i++) {
@@ -504,12 +503,12 @@ int btrfs_csum_one_bio(struct inode *inode, struct bio *bio, 
					+ total_bytes;

				index = 0;



				data = kmap_atomic(bvec->bv_page);

				data = kmap_atomic(bvec.bv_page);

			}



			sums->sums[index] = ~(u32)0;

			sums->sums[index]

				= btrfs_csum_data(data + bvec->bv_offset

				= btrfs_csum_data(data + bvec.bv_offset

						+ (i * fs_info->sectorsize),

						sums->sums[index],

						fs_info->sectorsize);

fs/btrfs/inode.c

+19 −16
Original line number Diff line number Diff line
@@ -7989,6 +7989,7 @@ static int dio_read_error(struct inode *inode, struct bio *failed_bio, 
	struct bio *bio;

	int isector;

	int read_mode = 0;

	int segs;

	int ret;



	BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
@@ -8004,9 +8005,9 @@ static int dio_read_error(struct inode *inode, struct bio *failed_bio, 
		return -EIO;

	}



	if ((failed_bio->bi_vcnt > 1)

		|| (failed_bio->bi_io_vec->bv_len

			> btrfs_inode_sectorsize(inode)))

	segs = bio_segments(failed_bio);

	if (segs > 1 ||

	    (failed_bio->bi_io_vec->bv_len > btrfs_inode_sectorsize(inode)))

		read_mode |= REQ_FAILFAST_DEV;



	isector = start - btrfs_io_bio(failed_bio)->logical;
@@ -8069,13 +8070,13 @@ 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 bio_vec bvec;

	struct bvec_iter iter;

	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;
@@ -8083,17 +8084,18 @@ static int __btrfs_correct_data_nocsum(struct inode *inode, 


	start = io_bio->logical;

	done.inode = inode;

	io_bio->bio.bi_iter = io_bio->iter;



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

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

		pgoff = bvec->bv_offset;

	bio_for_each_segment(bvec, &io_bio->bio, iter) {

		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,

		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);
@@ -8166,7 +8168,8 @@ 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 bio_vec bvec;

	struct bvec_iter iter;

	struct btrfs_retry_complete done;

	u64 start;

	u64 offset = 0;
@@ -8174,7 +8177,6 @@ static int __btrfs_subio_endio_read(struct inode *inode, 
	int nr_sectors;

	unsigned int pgoff;

	int csum_pos;

	int i;

	int ret;



	fs_info = BTRFS_I(inode)->root->fs_info;
@@ -8183,15 +8185,16 @@ static int __btrfs_subio_endio_read(struct inode *inode, 
	err = 0;

	start = io_bio->logical;

	done.inode = inode;

	io_bio->bio.bi_iter = io_bio->iter;



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

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

	bio_for_each_segment(bvec, &io_bio->bio, iter) {

		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);



		pgoff = bvec->bv_offset;

		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,

					bvec.bv_page, pgoff, start,

					sectorsize);

		if (likely(!ret))

			goto next;
@@ -8200,7 +8203,7 @@ try_again: 
		done.start = start;

		init_completion(&done.done);



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

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

				pgoff, start, start + sectorsize - 1,

				io_bio->mirror_num,

				btrfs_retry_endio, &done);

fs/btrfs/volumes.h

+1 −0
Original line number Diff line number Diff line
@@ -280,6 +280,7 @@ struct btrfs_io_bio { 
	u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];

	u8 *csum_allocated;

	btrfs_io_bio_end_io_t *end_io;

	struct bvec_iter iter;

	struct bio bio;

};

CRA Git | Maintained and supported by SUSTech CRA and CCSE