From fd9d6670edba68cedd87b3db04cbdcdfc492cc0a Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Thu, 16 Apr 2020 14:46:23 -0700 Subject: [PATCH] btrfs: simplify direct I/O read repair Direct I/O read repair was originally implemented in commit 8b110e393c5a ("Btrfs: implement repair function when direct read fails"). This implementation is unnecessarily complicated. There is major code duplication between __btrfs_subio_endio_read() (checks checksums and handles I/O errors for files with checksums), __btrfs_correct_data_nocsum() (handles I/O errors for files without checksums), btrfs_retry_endio() (checks checksums and handles I/O errors for retries of files with checksums), and btrfs_retry_endio_nocsum() (handles I/O errors for retries of files without checksum). If it sounds like these should be one function, that's because they should. Additionally, these functions are very hard to follow due to their excessive use of goto. This commit replaces the original implementation. After the previous commit getting rid of orig_bio, we can reuse the same endio callback for repair I/O and the original I/O, we just need to track the file offset and original iterator in the repair bio. We can also unify the handling of files with and without checksums and simplify the control flow. We also no longer have to wait for each repair I/O to complete one by one. Reviewed-by: Josef Bacik Reviewed-by: Nikolay Borisov Signed-off-by: Omar Sandoval Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 2 + fs/btrfs/inode.c | 284 ++++++++----------------------------------- 2 files changed, 52 insertions(+), 234 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 6ddf6d1c3e70..2b1f0becd680 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2630,6 +2630,8 @@ struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio, } bio_add_page(bio, page, failrec->len, pg_offset); + btrfs_io_bio(bio)->logical = failrec->start; + btrfs_io_bio(bio)->iter = bio->bi_iter; return bio; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 63e2f816d9cd..1462f64c2c4b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7435,19 +7435,17 @@ static int btrfs_check_dio_repairable(struct inode *inode, static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio, struct page *page, unsigned int pgoff, - u64 start, u64 end, int failed_mirror, - bio_end_io_t *repair_endio, void *repair_arg) + u64 start, u64 end, int failed_mirror) { + struct btrfs_dio_private *dip = failed_bio->bi_private; struct io_failure_record *failrec; struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree; struct bio *bio; int isector; unsigned int read_mode = 0; - int segs; int ret; blk_status_t status; - struct bio_vec bvec; BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE); @@ -7462,259 +7460,77 @@ static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio, return BLK_STS_IOERR; } - segs = bio_segments(failed_bio); - bio_get_first_bvec(failed_bio, &bvec); - if (segs > 1 || - (bvec.bv_len > btrfs_inode_sectorsize(inode))) + if (btrfs_io_bio(failed_bio)->iter.bi_size > inode->i_sb->s_blocksize) read_mode |= REQ_FAILFAST_DEV; 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, - pgoff, isector, repair_endio, repair_arg); + bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page, pgoff, + isector, failed_bio->bi_end_io, dip); bio->bi_opf = REQ_OP_READ | read_mode; btrfs_debug(BTRFS_I(inode)->root->fs_info, "repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d", read_mode, failrec->this_mirror, failrec->in_validation); + refcount_inc(&dip->refs); status = submit_dio_repair_bio(inode, bio, failrec->this_mirror); if (status) { free_io_failure(failure_tree, io_tree, failrec); bio_put(bio); + refcount_dec(&dip->refs); } return status; } -struct btrfs_retry_complete { - struct completion done; - struct inode *inode; - u64 start; - int uptodate; -}; - -static void btrfs_retry_endio_nocsum(struct bio *bio) -{ - struct btrfs_retry_complete *done = bio->bi_private; - struct inode *inode = done->inode; - struct bio_vec *bvec; - struct extent_io_tree *io_tree, *failure_tree; - struct bvec_iter_all iter_all; - - if (bio->bi_status) - goto end; - - ASSERT(bio->bi_vcnt == 1); - io_tree = &BTRFS_I(inode)->io_tree; - failure_tree = &BTRFS_I(inode)->io_failure_tree; - ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(inode)); - - done->uptodate = 1; - ASSERT(!bio_flagged(bio, BIO_CLONED)); - bio_for_each_segment_all(bvec, bio, iter_all) - clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree, - io_tree, done->start, bvec->bv_page, - btrfs_ino(BTRFS_I(inode)), 0); -end: - complete(&done->done); - bio_put(bio); -} - -static blk_status_t __btrfs_correct_data_nocsum(struct inode *inode, - struct btrfs_io_bio *io_bio) -{ - struct btrfs_fs_info *fs_info; - struct bio_vec bvec; - struct bvec_iter iter; - struct btrfs_retry_complete done; - u64 start; - unsigned int pgoff; - u32 sectorsize; - int nr_sectors; - blk_status_t ret; - blk_status_t err = BLK_STS_OK; - - fs_info = BTRFS_I(inode)->root->fs_info; - sectorsize = fs_info->sectorsize; - - start = io_bio->logical; - done.inode = inode; - io_bio->bio.bi_iter = io_bio->iter; - - 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, - pgoff, start, start + sectorsize - 1, - io_bio->mirror_num, - btrfs_retry_endio_nocsum, &done); - if (ret) { - err = ret; - goto next; - } - - wait_for_completion_io(&done.done); - - if (!done.uptodate) { - /* We might have another mirror, so try again */ - goto next_block_or_try_again; - } - -next: - start += sectorsize; - - nr_sectors--; - if (nr_sectors) { - pgoff += sectorsize; - ASSERT(pgoff < PAGE_SIZE); - goto next_block_or_try_again; - } - } - - return err; -} - -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 extent_io_tree *io_tree, *failure_tree; - struct inode *inode = done->inode; - struct bio_vec *bvec; - int uptodate; - int ret; - int i = 0; - struct bvec_iter_all iter_all; - - if (bio->bi_status) - goto end; - - uptodate = 1; - - ASSERT(bio->bi_vcnt == 1); - ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(done->inode)); - - io_tree = &BTRFS_I(inode)->io_tree; - failure_tree = &BTRFS_I(inode)->io_failure_tree; - - ASSERT(!bio_flagged(bio, BIO_CLONED)); - bio_for_each_segment_all(bvec, bio, iter_all) { - ret = check_data_csum(inode, io_bio, i, bvec->bv_page, - bvec->bv_offset, done->start, - bvec->bv_len); - if (!ret) - clean_io_failure(BTRFS_I(inode)->root->fs_info, - failure_tree, io_tree, done->start, - bvec->bv_page, - btrfs_ino(BTRFS_I(inode)), - bvec->bv_offset); - else - uptodate = 0; - i++; - } - - done->uptodate = uptodate; -end: - complete(&done->done); - bio_put(bio); -} - -static blk_status_t __btrfs_subio_endio_read(struct inode *inode, - struct btrfs_io_bio *io_bio, blk_status_t err) -{ - struct btrfs_fs_info *fs_info; - struct bio_vec bvec; - struct bvec_iter iter; - struct btrfs_retry_complete done; - u64 start; - u64 offset = 0; - u32 sectorsize; - int nr_sectors; - unsigned int pgoff; - int csum_pos; - bool uptodate = (err == 0); - int ret; - blk_status_t status; - - fs_info = BTRFS_I(inode)->root->fs_info; - sectorsize = fs_info->sectorsize; - - err = BLK_STS_OK; - start = io_bio->logical; - done.inode = inode; - io_bio->bio.bi_iter = io_bio->iter; - - 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: - if (uptodate) { - csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset); - ret = check_data_csum(inode, io_bio, csum_pos, - bvec.bv_page, pgoff, start, - sectorsize); - if (likely(!ret)) - goto next; - } -try_again: - done.uptodate = 0; - done.start = start; - init_completion(&done.done); - - status = dio_read_error(inode, &io_bio->bio, bvec.bv_page, - pgoff, start, start + sectorsize - 1, - io_bio->mirror_num, btrfs_retry_endio, - &done); - if (status) { - err = status; - goto next; - } - - wait_for_completion_io(&done.done); - - if (!done.uptodate) { - /* We might have another mirror, so try again */ - goto try_again; - } -next: - offset += sectorsize; - start += sectorsize; - - ASSERT(nr_sectors); - - nr_sectors--; - if (nr_sectors) { - pgoff += sectorsize; - ASSERT(pgoff < PAGE_SIZE); - goto next_block; - } - } - - return err; -} - static blk_status_t btrfs_check_read_dio_bio(struct inode *inode, struct btrfs_io_bio *io_bio, - blk_status_t err) + const bool uptodate) { - bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; + struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info; + const u32 sectorsize = fs_info->sectorsize; + struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree; + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + const bool csum = !(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM); + struct bio_vec bvec; + struct bvec_iter iter; + u64 start = io_bio->logical; + int icsum = 0; + blk_status_t err = BLK_STS_OK; - if (skip_csum) { - if (unlikely(err)) - return __btrfs_correct_data_nocsum(inode, io_bio); - else - return BLK_STS_OK; - } else { - return __btrfs_subio_endio_read(inode, io_bio, err); + __bio_for_each_segment(bvec, &io_bio->bio, iter, io_bio->iter) { + unsigned int i, nr_sectors, pgoff; + + nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len); + pgoff = bvec.bv_offset; + for (i = 0; i < nr_sectors; i++) { + ASSERT(pgoff < PAGE_SIZE); + if (uptodate && + (!csum || !check_data_csum(inode, io_bio, icsum, + bvec.bv_page, pgoff, + start, sectorsize))) { + clean_io_failure(fs_info, failure_tree, io_tree, + start, bvec.bv_page, + btrfs_ino(BTRFS_I(inode)), + pgoff); + } else { + blk_status_t status; + + status = dio_read_error(inode, &io_bio->bio, + bvec.bv_page, pgoff, + start, + start + sectorsize - 1, + io_bio->mirror_num); + if (status) + err = status; + } + start += sectorsize; + icsum++; + pgoff += sectorsize; + } } + return err; } static void __endio_write_update_ordered(struct inode *inode, @@ -7785,7 +7601,7 @@ static void btrfs_end_dio_bio(struct bio *bio) if (bio_op(bio) == REQ_OP_READ) { err = btrfs_check_read_dio_bio(dip->inode, btrfs_io_bio(bio), - err); + !err); } if (err)