From 17347cec15f919901c90cdbf98af47ed2ed28b9f Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Mon, 15 May 2017 15:33:27 -0700 Subject: [PATCH] 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: Liu Bo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 2 ++ fs/btrfs/file-item.c | 31 +++++++++++++++---------------- fs/btrfs/inode.c | 35 +++++++++++++++++++---------------- fs/btrfs/volumes.h | 1 + 4 files changed, 37 insertions(+), 32 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index db2bbf92b4bc..acb8c1d177e2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -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; } diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index 64fcb31d7163..9f6062c82419 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -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); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index c2e9c51c650e..ce6a9b2cce51 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -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); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 094521729df1..58b97b6f5f02 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -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; }; -- 2.30.2