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/mirror.c b/block/mirror.c
index d11706c..307b639 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -328,7 +328,6 @@
uint64_t delay_ns = 0;
/* At least the first dirty chunk is mirrored in one iteration. */
int nb_chunks = 1;
- int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
@@ -376,7 +375,7 @@
}
/* Clear dirty bits before querying the block status, because
- * calling bdrv_get_block_status_above could yield - if some blocks are
+ * calling bdrv_block_status_above could yield - if some blocks are
* marked dirty in this window, we need to know.
*/
bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
@@ -385,8 +384,7 @@
bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
while (nb_chunks > 0 && offset < s->bdev_length) {
- int64_t ret;
- int io_sectors;
+ int ret;
int64_t io_bytes;
int64_t io_bytes_acct;
enum MirrorMethod {
@@ -396,11 +394,9 @@
} mirror_method = MIRROR_METHOD_COPY;
assert(!(offset % s->granularity));
- ret = bdrv_get_block_status_above(source, NULL,
- offset >> BDRV_SECTOR_BITS,
- nb_chunks * sectors_per_chunk,
- &io_sectors, NULL);
- io_bytes = io_sectors * BDRV_SECTOR_SIZE;
+ ret = bdrv_block_status_above(source, NULL, offset,
+ nb_chunks * s->granularity,
+ &io_bytes, NULL, NULL);
if (ret < 0) {
io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);
} else if (ret & BDRV_BLOCK_DATA) {
@@ -1131,9 +1127,7 @@
granularity = bdrv_get_default_bitmap_granularity(target);
}
- assert ((granularity & (granularity - 1)) == 0);
- /* Granularity must be large enough for sector-based dirty bitmap */
- assert(granularity >= BDRV_SECTOR_SIZE);
+ assert(is_power_of_2(granularity));
if (buf_size < 0) {
error_setg(errp, "Invalid parameter 'buf-size'");
