From c40a3d38aff4e1c832d1692850621be7d5e5308c Mon Sep 17 00:00:00 2001 From: Chandan Rajendra Date: Thu, 21 Jan 2016 15:55:54 +0530 Subject: [PATCH] Btrfs: Compute and look up csums based on sectorsized blocks Checksums are applicable to sectorsize units. The current code uses bio->bv_len units to compute and look up checksums. This works on machines where sectorsize == PAGE_SIZE. This patch makes the checksum computation and look up code to work with sectorsize units. Reviewed-by: Liu Bo Signed-off-by: Chandan Rajendra Signed-off-by: David Sterba --- fs/btrfs/file-item.c | 92 ++++++++++++++++++++++++++++---------------- 1 file changed, 59 insertions(+), 33 deletions(-) diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index a67e1c828d0f..1c50a7b09b4e 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -172,6 +172,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, u64 item_start_offset = 0; u64 item_last_offset = 0; u64 disk_bytenr; + u64 page_bytes_left; u32 diff; int nblocks; int bio_index = 0; @@ -220,6 +221,8 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, disk_bytenr = (u64)bio->bi_iter.bi_sector << 9; if (dio) offset = logical_offset; + + page_bytes_left = bvec->bv_len; while (bio_index < bio->bi_vcnt) { if (!dio) offset = page_offset(bvec->bv_page) + bvec->bv_offset; @@ -243,7 +246,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, if (BTRFS_I(inode)->root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID) { set_extent_bits(io_tree, offset, - offset + bvec->bv_len - 1, + offset + root->sectorsize - 1, EXTENT_NODATASUM, GFP_NOFS); } else { btrfs_info(BTRFS_I(inode)->root->fs_info, @@ -281,11 +284,17 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, found: csum += count * csum_size; nblocks -= count; - bio_index += count; + while (count--) { - disk_bytenr += bvec->bv_len; - offset += bvec->bv_len; - bvec++; + disk_bytenr += root->sectorsize; + offset += root->sectorsize; + page_bytes_left -= root->sectorsize; + if (!page_bytes_left) { + bio_index++; + bvec++; + page_bytes_left = bvec->bv_len; + } + } } btrfs_free_path(path); @@ -432,6 +441,8 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, struct bio_vec *bvec = bio->bi_io_vec; int bio_index = 0; int index; + int nr_sectors; + int i; unsigned long total_bytes = 0; unsigned long this_sum_bytes = 0; u64 offset; @@ -459,41 +470,56 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, if (!contig) offset = page_offset(bvec->bv_page) + bvec->bv_offset; - if (offset >= ordered->file_offset + ordered->len || - offset < ordered->file_offset) { - unsigned long bytes_left; - sums->len = this_sum_bytes; - this_sum_bytes = 0; - btrfs_add_ordered_sum(inode, ordered, sums); - btrfs_put_ordered_extent(ordered); + data = kmap_atomic(bvec->bv_page); - bytes_left = bio->bi_iter.bi_size - total_bytes; + nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, + bvec->bv_len + root->sectorsize + - 1); + + for (i = 0; i < nr_sectors; i++) { + if (offset >= ordered->file_offset + ordered->len || + offset < ordered->file_offset) { + unsigned long bytes_left; + + kunmap_atomic(data); + sums->len = this_sum_bytes; + this_sum_bytes = 0; + btrfs_add_ordered_sum(inode, ordered, sums); + btrfs_put_ordered_extent(ordered); + + bytes_left = bio->bi_iter.bi_size - total_bytes; + + sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left), + GFP_NOFS); + BUG_ON(!sums); /* -ENOMEM */ + sums->len = bytes_left; + ordered = btrfs_lookup_ordered_extent(inode, + offset); + ASSERT(ordered); /* Logic error */ + sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) + + total_bytes; + index = 0; + + data = kmap_atomic(bvec->bv_page); + } - sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left), - GFP_NOFS); - BUG_ON(!sums); /* -ENOMEM */ - sums->len = bytes_left; - ordered = btrfs_lookup_ordered_extent(inode, offset); - BUG_ON(!ordered); /* Logic error */ - sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) + - total_bytes; - index = 0; + sums->sums[index] = ~(u32)0; + sums->sums[index] + = btrfs_csum_data(data + bvec->bv_offset + + (i * root->sectorsize), + sums->sums[index], + root->sectorsize); + btrfs_csum_final(sums->sums[index], + (char *)(sums->sums + index)); + index++; + offset += root->sectorsize; + this_sum_bytes += root->sectorsize; + total_bytes += root->sectorsize; } - data = kmap_atomic(bvec->bv_page); - sums->sums[index] = ~(u32)0; - sums->sums[index] = btrfs_csum_data(data + bvec->bv_offset, - sums->sums[index], - bvec->bv_len); kunmap_atomic(data); - btrfs_csum_final(sums->sums[index], - (char *)(sums->sums + index)); bio_index++; - index++; - total_bytes += bvec->bv_len; - this_sum_bytes += bvec->bv_len; - offset += bvec->bv_len; bvec++; } this_sum_bytes = 0; -- 2.30.2