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block: Switch bdrv_make_zero() to byte-based

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We are gradually converting to byte-based interfaces, as they are
easier to reason about than sector-based.  Change the internal
loop iteration of zeroing a device to track by bytes instead of
sectors (although we are still guaranteed that we iterate by steps
that are sector-aligned).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2017-10-11 22:47:01 -05:00 committed by Kevin Wolf
parent f06f6b66c7
commit 7286d6106f
1 changed files with 16 additions and 16 deletions
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32
block/io.c
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@ -716,38 +716,38 @@ int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
*/
int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)
{
int64_t target_sectors, ret, nb_sectors, sector_num = 0;
int64_t target_size, ret, bytes, offset = 0;
BlockDriverState *bs = child->bs;
int n;
int n; /* sectors */
target_sectors = bdrv_nb_sectors(bs);
if (target_sectors < 0) {
return target_sectors;
target_size = bdrv_getlength(bs);
if (target_size < 0) {
return target_size;
}
for (;;) {
nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
if (nb_sectors <= 0) {
bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES);
if (bytes <= 0) {
return 0;
}
ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, NULL);
ret = bdrv_get_block_status(bs, offset >> BDRV_SECTOR_BITS,
bytes >> BDRV_SECTOR_BITS, &n, NULL);
if (ret < 0) {
error_report("error getting block status at sector %" PRId64 ": %s",
sector_num, strerror(-ret));
error_report("error getting block status at offset %" PRId64 ": %s",
offset, strerror(-ret));
return ret;
}
if (ret & BDRV_BLOCK_ZERO) {
sector_num += n;
offset += n * BDRV_SECTOR_BITS;
continue;
}
ret = bdrv_pwrite_zeroes(child, sector_num << BDRV_SECTOR_BITS,
n << BDRV_SECTOR_BITS, flags);
ret = bdrv_pwrite_zeroes(child, offset, n * BDRV_SECTOR_SIZE, flags);
if (ret < 0) {
error_report("error writing zeroes at sector %" PRId64 ": %s",
sector_num, strerror(-ret));
error_report("error writing zeroes at offset %" PRId64 ": %s",
offset, strerror(-ret));
return ret;
}
sector_num += n;
offset += n * BDRV_SECTOR_SIZE;
}
}