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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>
This commit is contained in:
Chandan Rajendra 2016-01-21 15:55:54 +05:30 committed by David Sterba
parent 2e78c927d7
commit c40a3d38af
1 changed files with 59 additions and 33 deletions
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92
fs/btrfs/file-item.c
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@ -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);
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;
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->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;