From: Qu Wenruo Date: Thu, 6 Nov 2025 09:32:15 +0000 (+1030) Subject: btrfs: scrub: factor out parity scrub code into a helper X-Git-Tag: v6.19-rc1~167^2~54 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07166122b58a7fb3c056247aa262e832f3f38d0f;p=thirdparty%2Fkernel%2Flinux.git btrfs: scrub: factor out parity scrub code into a helper The function scrub_raid56_parity_stripe() is handling the parity stripe by the following steps: - Scrub each data stripes And make sure everything is fine in each data stripe - Cache the data stripe into the raid bio - Use the cached raid bio to scrub the target parity stripe Extract the last two steps into a new helper, scrub_raid56_cached_parity(), as a cleanup and make the error handling more straightforward. With the following minor cleanups: - Use on-stack bio structure The bio is always empty thus we do not need any bio vector nor the block device. Thus there is no need to allocate a bio, the on-stack one is more than enough to cut it. - Remove the unnecessary btrfs_put_bioc() call if btrfs_map_block() failed If btrfs_map_block() is failed, @bioc_ret will not be touched thus there is no need to call btrfs_put_bioc() in this case. - Use a proper out: tag to do the cleanup Now the error cleanup is much shorter and simpler, just btrfs_bio_counter_dec() and bio_uninit(). Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index ad7084c323d08..3029ef683fb99 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -2113,24 +2113,69 @@ static int should_cancel_scrub(const struct scrub_ctx *sctx) return 0; } +static int scrub_raid56_cached_parity(struct scrub_ctx *sctx, + struct btrfs_device *scrub_dev, + struct btrfs_chunk_map *map, + u64 full_stripe_start, + unsigned long *extent_bitmap) +{ + DECLARE_COMPLETION_ONSTACK(io_done); + struct btrfs_fs_info *fs_info = sctx->fs_info; + struct btrfs_io_context *bioc = NULL; + struct btrfs_raid_bio *rbio; + struct bio bio; + const int data_stripes = nr_data_stripes(map); + u64 length = btrfs_stripe_nr_to_offset(data_stripes); + int ret; + + bio_init(&bio, NULL, NULL, 0, REQ_OP_READ); + bio.bi_iter.bi_sector = full_stripe_start >> SECTOR_SHIFT; + bio.bi_private = &io_done; + bio.bi_end_io = raid56_scrub_wait_endio; + + btrfs_bio_counter_inc_blocked(fs_info); + ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, full_stripe_start, + &length, &bioc, NULL, NULL); + if (ret < 0) + goto out; + /* For RAID56 write there must be an @bioc allocated. */ + ASSERT(bioc); + rbio = raid56_parity_alloc_scrub_rbio(&bio, bioc, scrub_dev, extent_bitmap, + BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits); + btrfs_put_bioc(bioc); + if (!rbio) { + ret = -ENOMEM; + goto out; + } + /* Use the recovered stripes as cache to avoid read them from disk again. */ + for (int i = 0; i < data_stripes; i++) { + struct scrub_stripe *stripe = &sctx->raid56_data_stripes[i]; + + raid56_parity_cache_data_folios(rbio, stripe->folios, + full_stripe_start + (i << BTRFS_STRIPE_LEN_SHIFT)); + } + raid56_parity_submit_scrub_rbio(rbio); + wait_for_completion_io(&io_done); + ret = blk_status_to_errno(bio.bi_status); +out: + btrfs_bio_counter_dec(fs_info); + bio_uninit(&bio); + return ret; +} + static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx, struct btrfs_device *scrub_dev, struct btrfs_block_group *bg, struct btrfs_chunk_map *map, u64 full_stripe_start) { - DECLARE_COMPLETION_ONSTACK(io_done); struct btrfs_fs_info *fs_info = sctx->fs_info; - struct btrfs_raid_bio *rbio; - struct btrfs_io_context *bioc = NULL; struct btrfs_path extent_path = { 0 }; struct btrfs_path csum_path = { 0 }; - struct bio *bio; struct scrub_stripe *stripe; bool all_empty = true; const int data_stripes = nr_data_stripes(map); unsigned long extent_bitmap = 0; - u64 length = btrfs_stripe_nr_to_offset(data_stripes); int ret; ASSERT(sctx->raid56_data_stripes); @@ -2252,42 +2297,8 @@ static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx, } /* Now we can check and regenerate the P/Q stripe. */ - bio = bio_alloc(NULL, 1, REQ_OP_READ, GFP_NOFS); - bio->bi_iter.bi_sector = full_stripe_start >> SECTOR_SHIFT; - bio->bi_private = &io_done; - bio->bi_end_io = raid56_scrub_wait_endio; - - btrfs_bio_counter_inc_blocked(fs_info); - ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, full_stripe_start, - &length, &bioc, NULL, NULL); - if (ret < 0) { - bio_put(bio); - btrfs_put_bioc(bioc); - btrfs_bio_counter_dec(fs_info); - goto out; - } - rbio = raid56_parity_alloc_scrub_rbio(bio, bioc, scrub_dev, &extent_bitmap, - BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits); - btrfs_put_bioc(bioc); - if (!rbio) { - ret = -ENOMEM; - bio_put(bio); - btrfs_bio_counter_dec(fs_info); - goto out; - } - /* Use the recovered stripes as cache to avoid read them from disk again. */ - for (int i = 0; i < data_stripes; i++) { - stripe = &sctx->raid56_data_stripes[i]; - - raid56_parity_cache_data_folios(rbio, stripe->folios, - full_stripe_start + (i << BTRFS_STRIPE_LEN_SHIFT)); - } - raid56_parity_submit_scrub_rbio(rbio); - wait_for_completion_io(&io_done); - ret = blk_status_to_errno(bio->bi_status); - bio_put(bio); - btrfs_bio_counter_dec(fs_info); - + ret = scrub_raid56_cached_parity(sctx, scrub_dev, map, full_stripe_start, + &extent_bitmap); out: btrfs_release_path(&extent_path); btrfs_release_path(&csum_path);