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block: Make bdrv_is_allocated_above() byte-based

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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 signature of the function to use int64_t *pnum ensures
that the compiler enforces that all callers are updated.  For now,
the io.c layer still assert()s that all callers are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status.  Therefore, for the most part this patch is just the
addition of scaling at the callers followed by inverse scaling at
bdrv_is_allocated().  But some code, particularly stream_run(),
gets a lot simpler because it no longer has to mess with sectors.
Leave comments where we can further simplify by switching to
byte-based iterations, once later patches eliminate the need for
sector-aligned operations.

For ease of review, bdrv_is_allocated() was tackled separately.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2017-07-07 07:44:59 -05:00 • committed by Kevin Wolf
parent c00716beb3
commit 51b0a48888
7 changed files with 65 additions and 56 deletions
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13
qemu-img.c
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@ -1508,12 +1508,16 @@ static int img_compare(int argc, char **argv)
}
for (;;) {
int64_t count;
nb_sectors = sectors_to_process(total_sectors_over, sector_num);
if (nb_sectors <= 0) {
break;
}
ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL, sector_num,
nb_sectors, &pnum);
ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL,
sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
&count);
if (ret < 0) {
ret = 3;
error_report("Sector allocation test failed for %s",
@ -1521,7 +1525,10 @@ static int img_compare(int argc, char **argv)
goto out;
}
nb_sectors = pnum;
/* TODO relax this once bdrv_is_allocated_above does not enforce
* sector alignment */
assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
nb_sectors = count >> BDRV_SECTOR_BITS;
if (ret) {
ret = check_empty_sectors(blk_over, sector_num, nb_sectors,
filename_over, buf1, quiet);