From adbfd189c4695862c464da87b3e574241452d73d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 9 Apr 2025 13:10:41 +0200 Subject: [PATCH] btrfs: scrub: use virtual addresses directly Instead of the old @page and @page_offset pair inside scrub, here we can directly use the virtual address for a sector. This has the following benefit: - Simplified parameters A single @kaddr will repair @page and @page_offset. - No more unnecessary kmap/kunmap calls Since all pages utilized by scrub is allocated by scrub, and no highmem is allowed, we do not need to do any kmap/kunmap. And add an ASSERT() inside the new scrub_stripe_get_kaddr() to catch any unexpected highmem page. Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: Qu Wenruo Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/scrub.c | 95 +++++++++++++++++++----------------------------- 1 file changed, 38 insertions(+), 57 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 3794205a47a4..5d6166fd917e 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -579,20 +579,15 @@ static int fill_writer_pointer_gap(struct scrub_ctx *sctx, u64 physical) return ret; } -static struct page *scrub_stripe_get_page(struct scrub_stripe *stripe, int sector_nr) +static void *scrub_stripe_get_kaddr(struct scrub_stripe *stripe, int sector_nr) { - struct btrfs_fs_info *fs_info = stripe->bg->fs_info; - int page_index = (sector_nr << fs_info->sectorsize_bits) >> PAGE_SHIFT; - - return stripe->pages[page_index]; -} - -static unsigned int scrub_stripe_get_page_offset(struct scrub_stripe *stripe, - int sector_nr) -{ - struct btrfs_fs_info *fs_info = stripe->bg->fs_info; + u32 offset = (sector_nr << stripe->bg->fs_info->sectorsize_bits); + const struct page *page = stripe->pages[offset >> PAGE_SHIFT]; - return offset_in_page(sector_nr << fs_info->sectorsize_bits); + /* stripe->pages[] is allocated by us and no highmem is allowed. */ + ASSERT(page); + ASSERT(!PageHighMem(page)); + return page_address(page) + offset_in_page(offset); } static void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr) @@ -600,19 +595,17 @@ static void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr struct btrfs_fs_info *fs_info = stripe->bg->fs_info; const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits; const u64 logical = stripe->logical + (sector_nr << fs_info->sectorsize_bits); - const struct page *first_page = scrub_stripe_get_page(stripe, sector_nr); - const unsigned int first_off = scrub_stripe_get_page_offset(stripe, sector_nr); + void *first_kaddr = scrub_stripe_get_kaddr(stripe, sector_nr); + struct btrfs_header *header = first_kaddr; SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); u8 on_disk_csum[BTRFS_CSUM_SIZE]; u8 calculated_csum[BTRFS_CSUM_SIZE]; - struct btrfs_header *header; /* * Here we don't have a good way to attach the pages (and subpages) * to a dummy extent buffer, thus we have to directly grab the members * from pages. */ - header = (struct btrfs_header *)(page_address(first_page) + first_off); memcpy(on_disk_csum, header->csum, fs_info->csum_size); if (logical != btrfs_stack_header_bytenr(header)) { @@ -648,14 +641,11 @@ static void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr /* Now check tree block csum. */ shash->tfm = fs_info->csum_shash; crypto_shash_init(shash); - crypto_shash_update(shash, page_address(first_page) + first_off + - BTRFS_CSUM_SIZE, fs_info->sectorsize - BTRFS_CSUM_SIZE); + crypto_shash_update(shash, first_kaddr + BTRFS_CSUM_SIZE, + fs_info->sectorsize - BTRFS_CSUM_SIZE); for (int i = sector_nr + 1; i < sector_nr + sectors_per_tree; i++) { - struct page *page = scrub_stripe_get_page(stripe, i); - unsigned int page_off = scrub_stripe_get_page_offset(stripe, i); - - crypto_shash_update(shash, page_address(page) + page_off, + crypto_shash_update(shash, scrub_stripe_get_kaddr(stripe, i), fs_info->sectorsize); } @@ -691,10 +681,8 @@ static void scrub_verify_one_sector(struct scrub_stripe *stripe, int sector_nr) struct btrfs_fs_info *fs_info = stripe->bg->fs_info; struct scrub_sector_verification *sector = &stripe->sectors[sector_nr]; const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits; - struct page *page = scrub_stripe_get_page(stripe, sector_nr); - unsigned int pgoff = scrub_stripe_get_page_offset(stripe, sector_nr); + void *kaddr = scrub_stripe_get_kaddr(stripe, sector_nr); u8 csum_buf[BTRFS_CSUM_SIZE]; - void *kaddr; int ret; ASSERT(sector_nr >= 0 && sector_nr < stripe->nr_sectors); @@ -738,9 +726,7 @@ static void scrub_verify_one_sector(struct scrub_stripe *stripe, int sector_nr) return; } - kaddr = kmap_local_page(page) + pgoff; ret = btrfs_check_sector_csum(fs_info, kaddr, csum_buf, sector->csum); - kunmap_local(kaddr); if (ret < 0) { set_bit(sector_nr, &stripe->csum_error_bitmap); set_bit(sector_nr, &stripe->error_bitmap); @@ -769,8 +755,7 @@ static int calc_sector_number(struct scrub_stripe *stripe, struct bio_vec *first int i; for (i = 0; i < stripe->nr_sectors; i++) { - if (scrub_stripe_get_page(stripe, i) == first_bvec->bv_page && - scrub_stripe_get_page_offset(stripe, i) == first_bvec->bv_offset) + if (scrub_stripe_get_kaddr(stripe, i) == bvec_virt(first_bvec)) break; } ASSERT(i < stripe->nr_sectors); @@ -817,6 +802,25 @@ static int calc_next_mirror(int mirror, int num_copies) return (mirror + 1 > num_copies) ? 1 : mirror + 1; } +static void scrub_bio_add_sector(struct btrfs_bio *bbio, struct scrub_stripe *stripe, + int sector_nr) +{ + void *kaddr = scrub_stripe_get_kaddr(stripe, sector_nr); + int ret; + + ret = bio_add_page(&bbio->bio, virt_to_page(kaddr), bbio->fs_info->sectorsize, + offset_in_page(kaddr)); + /* + * Caller should ensure the bbio has enough size. + * And we cannot use __bio_add_page(), which doesn't do any merge. + * + * Meanwhile for scrub_submit_initial_read() we fully rely on the merge + * to create the minimal amount of bio vectors, for fs block size < page + * size cases. + */ + ASSERT(ret == bbio->fs_info->sectorsize); +} + static void scrub_stripe_submit_repair_read(struct scrub_stripe *stripe, int mirror, int blocksize, bool wait) { @@ -829,13 +833,6 @@ static void scrub_stripe_submit_repair_read(struct scrub_stripe *stripe, ASSERT(atomic_read(&stripe->pending_io) == 0); for_each_set_bit(i, &old_error_bitmap, stripe->nr_sectors) { - struct page *page; - int pgoff; - int ret; - - page = scrub_stripe_get_page(stripe, i); - pgoff = scrub_stripe_get_page_offset(stripe, i); - /* The current sector cannot be merged, submit the bio. */ if (bbio && ((i > 0 && !test_bit(i - 1, &stripe->error_bitmap)) || bbio->bio.bi_iter.bi_size >= blocksize)) { @@ -854,8 +851,7 @@ static void scrub_stripe_submit_repair_read(struct scrub_stripe *stripe, (i << fs_info->sectorsize_bits)) >> SECTOR_SHIFT; } - ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff); - ASSERT(ret == fs_info->sectorsize); + scrub_bio_add_sector(bbio, stripe, i); } if (bbio) { ASSERT(bbio->bio.bi_iter.bi_size); @@ -1202,10 +1198,6 @@ static void scrub_write_sectors(struct scrub_ctx *sctx, struct scrub_stripe *str int sector_nr; for_each_set_bit(sector_nr, &write_bitmap, stripe->nr_sectors) { - struct page *page = scrub_stripe_get_page(stripe, sector_nr); - unsigned int pgoff = scrub_stripe_get_page_offset(stripe, sector_nr); - int ret; - /* We should only writeback sectors covered by an extent. */ ASSERT(test_bit(sector_nr, &stripe->extent_sector_bitmap)); @@ -1221,8 +1213,7 @@ static void scrub_write_sectors(struct scrub_ctx *sctx, struct scrub_stripe *str (sector_nr << fs_info->sectorsize_bits)) >> SECTOR_SHIFT; } - ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff); - ASSERT(ret == fs_info->sectorsize); + scrub_bio_add_sector(bbio, stripe, sector_nr); } if (bbio) scrub_submit_write_bio(sctx, stripe, bbio, dev_replace); @@ -1675,9 +1666,6 @@ static void scrub_submit_extent_sector_read(struct scrub_stripe *stripe) atomic_inc(&stripe->pending_io); for_each_set_bit(i, &stripe->extent_sector_bitmap, stripe->nr_sectors) { - struct page *page = scrub_stripe_get_page(stripe, i); - unsigned int pgoff = scrub_stripe_get_page_offset(stripe, i); - /* We're beyond the chunk boundary, no need to read anymore. */ if (i >= nr_sectors) break; @@ -1730,7 +1718,7 @@ static void scrub_submit_extent_sector_read(struct scrub_stripe *stripe) bbio->bio.bi_iter.bi_sector = logical >> SECTOR_SHIFT; } - __bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff); + scrub_bio_add_sector(bbio, stripe, i); } if (bbio) { @@ -1768,15 +1756,8 @@ static void scrub_submit_initial_read(struct scrub_ctx *sctx, bbio->bio.bi_iter.bi_sector = stripe->logical >> SECTOR_SHIFT; /* Read the whole range inside the chunk boundary. */ - for (unsigned int cur = 0; cur < nr_sectors; cur++) { - struct page *page = scrub_stripe_get_page(stripe, cur); - unsigned int pgoff = scrub_stripe_get_page_offset(stripe, cur); - int ret; - - ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff); - /* We should have allocated enough bio vectors. */ - ASSERT(ret == fs_info->sectorsize); - } + for (unsigned int cur = 0; cur < nr_sectors; cur++) + scrub_bio_add_sector(bbio, stripe, cur); atomic_inc(&stripe->pending_io); /* -- 2.25.1