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 <bo.li.liu@oracle.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index a67e1c8..1c50a7b 100644 (file)
--- 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;