On Mon, Jun 01, 2015 at 08:52:43PM +0530, Chandan Rajendra wrote:
> 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 <bo.li.liu@xxxxxxxxxx>
Thanks,
-liubo
>
> Signed-off-by: Chandan Rajendra <chandan@xxxxxxxxxxxxxxxxxx>
> ---
> fs/btrfs/file-item.c | 87 ++++++++++++++++++++++++++++++++--------------------
> 1 file changed, 54 insertions(+), 33 deletions(-)
>
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index 58ece65..65ab9c3 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 +470,51 @@ 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;
>
> - 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;
> + nr_sectors = (bvec->bv_len + root->sectorsize - 1)
> + >> root->fs_info->sb->s_blocksize_bits;
> +
> +
> + for (i = 0; i < nr_sectors; i++) {
> + 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);
> +
> + 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);
> + 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;
> --
> 2.1.0
>
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