Fix DM verity target's optional Forward Error Correction (FEC) for

Reed-Solomon roots that are unaligned to block size.
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Merge tag 'for-5.12/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Fix DM verity target's optional Forward Error Correction (FEC) for
  Reed-Solomon roots that are unaligned to block size"

* tag 'for-5.12/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm verity: fix FEC for RS roots unaligned to block size
  dm bufio: subtract the number of initial sectors in dm_bufio_get_device_size
This commit is contained in:
Linus Torvalds 2021-03-05 13:25:23 -08:00
commit 63dcd69d9b
2 changed files with 16 additions and 11 deletions

View File

@ -1526,6 +1526,10 @@ EXPORT_SYMBOL_GPL(dm_bufio_get_block_size);
sector_t dm_bufio_get_device_size(struct dm_bufio_client *c)
{
sector_t s = i_size_read(c->bdev->bd_inode) >> SECTOR_SHIFT;
if (s >= c->start)
s -= c->start;
else
s = 0;
if (likely(c->sectors_per_block_bits >= 0))
s >>= c->sectors_per_block_bits;
else

View File

@ -61,19 +61,18 @@ static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
unsigned *offset, struct dm_buffer **buf)
{
u64 position, block;
u64 position, block, rem;
u8 *res;
position = (index + rsb) * v->fec->roots;
block = position >> v->data_dev_block_bits;
*offset = (unsigned)(position - (block << v->data_dev_block_bits));
block = div64_u64_rem(position, v->fec->roots << SECTOR_SHIFT, &rem);
*offset = (unsigned)rem;
res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf);
res = dm_bufio_read(v->fec->bufio, block, buf);
if (IS_ERR(res)) {
DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
v->data_dev->name, (unsigned long long)rsb,
(unsigned long long)(v->fec->start + block),
PTR_ERR(res));
(unsigned long long)block, PTR_ERR(res));
*buf = NULL;
}
@ -155,7 +154,7 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio,
/* read the next block when we run out of parity bytes */
offset += v->fec->roots;
if (offset >= 1 << v->data_dev_block_bits) {
if (offset >= v->fec->roots << SECTOR_SHIFT) {
dm_bufio_release(buf);
par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
@ -674,7 +673,7 @@ int verity_fec_ctr(struct dm_verity *v)
{
struct dm_verity_fec *f = v->fec;
struct dm_target *ti = v->ti;
u64 hash_blocks;
u64 hash_blocks, fec_blocks;
int ret;
if (!verity_fec_is_enabled(v)) {
@ -744,15 +743,17 @@ int verity_fec_ctr(struct dm_verity *v)
}
f->bufio = dm_bufio_client_create(f->dev->bdev,
1 << v->data_dev_block_bits,
f->roots << SECTOR_SHIFT,
1, 0, NULL, NULL);
if (IS_ERR(f->bufio)) {
ti->error = "Cannot initialize FEC bufio client";
return PTR_ERR(f->bufio);
}
if (dm_bufio_get_device_size(f->bufio) <
((f->start + f->rounds * f->roots) >> v->data_dev_block_bits)) {
dm_bufio_set_sector_offset(f->bufio, f->start << (v->data_dev_block_bits - SECTOR_SHIFT));
fec_blocks = div64_u64(f->rounds * f->roots, v->fec->roots << SECTOR_SHIFT);
if (dm_bufio_get_device_size(f->bufio) < fec_blocks) {
ti->error = "FEC device is too small";
return -E2BIG;
}