From 852eee62d31abd695cd43e1b875d664ed292a8ca Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 21 Jan 2023 07:50:20 +0100 Subject: [PATCH] btrfs: allow btrfs_submit_bio to split bios Currently the I/O submitters have to split bios according to the chunk stripe boundaries. This leads to extra lookups in the extent trees and a lot of boilerplate code. To drop this requirement, split the bio when __btrfs_map_block returns a mapping that is smaller than the requested size and keep a count of pending bios in the original btrfs_bio so that the upper level completion is only invoked when all clones have completed. Based on a patch from Qu Wenruo. Reviewed-by: Josef Bacik Reviewed-by: Johannes Thumshirn Reviewed-by: Qu Wenruo Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba --- fs/btrfs/bio.c | 110 +++++++++++++++++++++++++++++++++++++++++-------- fs/btrfs/bio.h | 1 + 2 files changed, 93 insertions(+), 18 deletions(-) diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c index 27e46757fdd858..521a909292a064 100644 --- a/fs/btrfs/bio.c +++ b/fs/btrfs/bio.c @@ -17,6 +17,7 @@ #include "file-item.h" static struct bio_set btrfs_bioset; +static struct bio_set btrfs_clone_bioset; static struct bio_set btrfs_repair_bioset; static mempool_t btrfs_failed_bio_pool; @@ -38,6 +39,7 @@ static inline void btrfs_bio_init(struct btrfs_bio *bbio, bbio->inode = inode; bbio->end_io = end_io; bbio->private = private; + atomic_set(&bbio->pending_ios, 1); } /* @@ -75,6 +77,59 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size, return bio; } +static struct bio *btrfs_split_bio(struct bio *orig, u64 map_length) +{ + struct btrfs_bio *orig_bbio = btrfs_bio(orig); + struct bio *bio; + + bio = bio_split(orig, map_length >> SECTOR_SHIFT, GFP_NOFS, + &btrfs_clone_bioset); + btrfs_bio_init(btrfs_bio(bio), orig_bbio->inode, NULL, orig_bbio); + + btrfs_bio(bio)->file_offset = orig_bbio->file_offset; + if (!(orig->bi_opf & REQ_BTRFS_ONE_ORDERED)) + orig_bbio->file_offset += map_length; + + atomic_inc(&orig_bbio->pending_ios); + return bio; +} + +static void btrfs_orig_write_end_io(struct bio *bio); + +static void btrfs_bbio_propagate_error(struct btrfs_bio *bbio, + struct btrfs_bio *orig_bbio) +{ + /* + * For writes we tolerate nr_mirrors - 1 write failures, so we can't + * just blindly propagate a write failure here. Instead increment the + * error count in the original I/O context so that it is guaranteed to + * be larger than the error tolerance. + */ + if (bbio->bio.bi_end_io == &btrfs_orig_write_end_io) { + struct btrfs_io_stripe *orig_stripe = orig_bbio->bio.bi_private; + struct btrfs_io_context *orig_bioc = orig_stripe->bioc; + + atomic_add(orig_bioc->max_errors, &orig_bioc->error); + } else { + orig_bbio->bio.bi_status = bbio->bio.bi_status; + } +} + +static void btrfs_orig_bbio_end_io(struct btrfs_bio *bbio) +{ + if (bbio->bio.bi_pool == &btrfs_clone_bioset) { + struct btrfs_bio *orig_bbio = bbio->private; + + if (bbio->bio.bi_status) + btrfs_bbio_propagate_error(bbio, orig_bbio); + bio_put(&bbio->bio); + bbio = orig_bbio; + } + + if (atomic_dec_and_test(&bbio->pending_ios)) + bbio->end_io(bbio); +} + static int next_repair_mirror(struct btrfs_failed_bio *fbio, int cur_mirror) { if (cur_mirror == fbio->num_copies) @@ -92,7 +147,7 @@ static int prev_repair_mirror(struct btrfs_failed_bio *fbio, int cur_mirror) static void btrfs_repair_done(struct btrfs_failed_bio *fbio) { if (atomic_dec_and_test(&fbio->repair_count)) { - fbio->bbio->end_io(fbio->bbio); + btrfs_orig_bbio_end_io(fbio->bbio); mempool_free(fbio, &btrfs_failed_bio_pool); } } @@ -229,7 +284,7 @@ static void btrfs_check_read_bio(struct btrfs_bio *bbio, struct btrfs_device *de if (fbio) btrfs_repair_done(fbio); else - bbio->end_io(bbio); + btrfs_orig_bbio_end_io(bbio); } static void btrfs_log_dev_io_error(struct bio *bio, struct btrfs_device *dev) @@ -283,7 +338,7 @@ static void btrfs_simple_end_io(struct bio *bio) } else { if (bio_op(bio) == REQ_OP_ZONE_APPEND) btrfs_record_physical_zoned(bbio); - bbio->end_io(bbio); + btrfs_orig_bbio_end_io(bbio); } } @@ -297,7 +352,7 @@ static void btrfs_raid56_end_io(struct bio *bio) if (bio_op(bio) == REQ_OP_READ && !(bbio->bio.bi_opf & REQ_META)) btrfs_check_read_bio(bbio, NULL); else - bbio->end_io(bbio); + btrfs_orig_bbio_end_io(bbio); btrfs_put_bioc(bioc); } @@ -324,7 +379,7 @@ static void btrfs_orig_write_end_io(struct bio *bio) else bio->bi_status = BLK_STS_OK; - bbio->end_io(bbio); + btrfs_orig_bbio_end_io(bbio); btrfs_put_bioc(bioc); } @@ -488,7 +543,7 @@ static void run_one_async_done(struct btrfs_work *work) /* If an error occurred we just want to clean up the bio and move on. */ if (bio->bi_status) { - btrfs_bio_end_io(async->bbio, bio->bi_status); + btrfs_orig_bbio_end_io(async->bbio); return; } @@ -563,9 +618,11 @@ static bool btrfs_wq_submit_bio(struct btrfs_bio *bbio, return true; } -void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror_num) +static bool btrfs_submit_chunk(struct btrfs_fs_info *fs_info, struct bio *bio, + int mirror_num) { struct btrfs_bio *bbio = btrfs_bio(bio); + struct btrfs_bio *orig_bbio = bbio; u64 logical = bio->bi_iter.bi_sector << 9; u64 length = bio->bi_iter.bi_size; u64 map_length = length; @@ -582,11 +639,10 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror goto fail; } + map_length = min(map_length, length); if (map_length < length) { - btrfs_crit(fs_info, - "mapping failed logical %llu bio len %llu len %llu", - logical, length, map_length); - BUG(); + bio = btrfs_split_bio(bio, map_length); + bbio = btrfs_bio(bio); } /* @@ -597,14 +653,14 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror bbio->saved_iter = bio->bi_iter; ret = btrfs_lookup_bio_sums(bbio); if (ret) - goto fail; + goto fail_put_bio; } if (btrfs_op(bio) == BTRFS_MAP_WRITE) { if (bio_op(bio) == REQ_OP_ZONE_APPEND) { ret = btrfs_extract_ordered_extent(btrfs_bio(bio)); if (ret) - goto fail; + goto fail_put_bio; } /* @@ -616,20 +672,32 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror !btrfs_is_data_reloc_root(bbio->inode->root)) { if (should_async_write(bbio) && btrfs_wq_submit_bio(bbio, bioc, &smap, mirror_num)) - return; + goto done; ret = btrfs_bio_csum(bbio); if (ret) - goto fail; + goto fail_put_bio; } } __btrfs_submit_bio(bio, bioc, &smap, mirror_num); - return; +done: + return map_length == length; +fail_put_bio: + if (map_length < length) + bio_put(bio); fail: btrfs_bio_counter_dec(fs_info); - btrfs_bio_end_io(bbio, ret); + btrfs_bio_end_io(orig_bbio, ret); + /* Do not submit another chunk */ + return true; +} + +void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror_num) +{ + while (!btrfs_submit_chunk(fs_info, bio, mirror_num)) + ; } /* @@ -737,10 +805,13 @@ int __init btrfs_bioset_init(void) offsetof(struct btrfs_bio, bio), BIOSET_NEED_BVECS)) return -ENOMEM; + if (bioset_init(&btrfs_clone_bioset, BIO_POOL_SIZE, + offsetof(struct btrfs_bio, bio), 0)) + goto out_free_bioset; if (bioset_init(&btrfs_repair_bioset, BIO_POOL_SIZE, offsetof(struct btrfs_bio, bio), BIOSET_NEED_BVECS)) - goto out_free_bioset; + goto out_free_clone_bioset; if (mempool_init_kmalloc_pool(&btrfs_failed_bio_pool, BIO_POOL_SIZE, sizeof(struct btrfs_failed_bio))) goto out_free_repair_bioset; @@ -748,6 +819,8 @@ int __init btrfs_bioset_init(void) out_free_repair_bioset: bioset_exit(&btrfs_repair_bioset); +out_free_clone_bioset: + bioset_exit(&btrfs_clone_bioset); out_free_bioset: bioset_exit(&btrfs_bioset); return -ENOMEM; @@ -757,5 +830,6 @@ void __cold btrfs_bioset_exit(void) { mempool_exit(&btrfs_failed_bio_pool); bioset_exit(&btrfs_repair_bioset); + bioset_exit(&btrfs_clone_bioset); bioset_exit(&btrfs_bioset); } diff --git a/fs/btrfs/bio.h b/fs/btrfs/bio.h index 4142004ce053a1..67d416cf293dc1 100644 --- a/fs/btrfs/bio.h +++ b/fs/btrfs/bio.h @@ -55,6 +55,7 @@ struct btrfs_bio { /* For internal use in read end I/O handling */ unsigned int mirror_num; + atomic_t pending_ios; struct work_struct end_io_work; /*