block: Convert bdrv_get_block_status_above() to bytes
We are gradually moving away from sector-based interfaces, towards
byte-based. In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.
Changing the name of the function from bdrv_get_block_status_above()
to bdrv_block_status_above() ensures that the compiler enforces that
all callers are updated. Likewise, since it a byte interface allows
an offset mapping that might not be sector aligned, split the mapping
out of the return value and into a pass-by-reference parameter. For
now, the io.c layer still assert()s that all uses are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status in the drivers.
For the most part this patch is just the addition of scaling at the
callers followed by inverse scaling at bdrv_block_status(), plus
updates for the new split return interface. But some code,
particularly bdrv_block_status(), gets a lot simpler because it no
longer has to mess with sectors. Likewise, mirror code no longer
computes s->granularity >> BDRV_SECTOR_BITS, and can therefore drop
an assertion about alignment because the loop no longer depends on
alignment (never mind that we don't really have a driver that
reports sub-sector alignments, so it's not really possible to test
the effect of sub-sector mirroring). Fix a neighboring assertion to
use is_power_of_2 while there.
For ease of review, bdrv_get_block_status() was tackled separately.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 795be67..29d0a50 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2974,8 +2974,8 @@
static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
{
- int nr;
- int64_t res;
+ int64_t nr;
+ int res;
int64_t start;
/* TODO: Widening to sector boundaries should only be needed as
@@ -2991,10 +2991,8 @@
if (!bytes) {
return true;
}
- res = bdrv_get_block_status_above(bs, NULL, start >> BDRV_SECTOR_BITS,
- bytes >> BDRV_SECTOR_BITS, &nr, NULL);
- return res >= 0 && (res & BDRV_BLOCK_ZERO) &&
- nr * BDRV_SECTOR_SIZE == bytes;
+ res = bdrv_block_status_above(bs, NULL, start, bytes, &nr, NULL, NULL);
+ return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;
}
static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
@@ -3700,17 +3698,14 @@
required = virtual_size;
} else {
int64_t offset;
- int pnum = 0;
+ int64_t pnum = 0;
- for (offset = 0; offset < ssize;
- offset += pnum * BDRV_SECTOR_SIZE) {
- int nb_sectors = MIN(ssize - offset,
- BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE;
- int64_t ret;
+ for (offset = 0; offset < ssize; offset += pnum) {
+ int ret;
- ret = bdrv_get_block_status_above(in_bs, NULL,
- offset >> BDRV_SECTOR_BITS,
- nb_sectors, &pnum, NULL);
+ ret = bdrv_block_status_above(in_bs, NULL, offset,
+ ssize - offset, &pnum, NULL,
+ NULL);
if (ret < 0) {
error_setg_errno(&local_err, -ret,
"Unable to get block status");
@@ -3722,11 +3717,10 @@
} else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==
(BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {
/* Extend pnum to end of cluster for next iteration */
- pnum = (ROUND_UP(offset + pnum * BDRV_SECTOR_SIZE,
- cluster_size) - offset) >> BDRV_SECTOR_BITS;
+ pnum = ROUND_UP(offset + pnum, cluster_size) - offset;
/* Count clusters we've seen */
- required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE;
+ required += offset % cluster_size + pnum;
}
}
}
