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block: Convert bdrv_get_block_status_above() to bytes

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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 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>
This commit is contained in:
Eric Blake 2017-10-11 22:47:08 -05:00 committed by Kevin Wolf
parent 5b648c67e3
commit 3182664220
5 changed files with 57 additions and 103 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
block/io.c
View File

@ -2016,7 +2016,7 @@ static int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs,
return ret;
}
/* Coroutine wrapper for bdrv_get_block_status_above() */
/* Coroutine wrapper for bdrv_block_status_above() */
static void coroutine_fn bdrv_block_status_above_co_entry(void *opaque)
{
BdrvCoBlockStatusData *data = opaque;
@ -2064,58 +2064,19 @@ static int bdrv_common_block_status_above(BlockDriverState *bs,
return data.ret;
}
int64_t bdrv_get_block_status_above(BlockDriverState *bs,
BlockDriverState *base,
int64_t sector_num,
int nb_sectors, int *pnum,
BlockDriverState **file)
int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
int64_t offset, int64_t bytes, int64_t *pnum,
int64_t *map, BlockDriverState **file)
{
int64_t ret;
int64_t n;
int64_t map;
ret = bdrv_common_block_status_above(bs, base, true,
sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
&n, &map, file);
if (ret < 0) {
*pnum = 0;
return ret;
}
assert(QEMU_IS_ALIGNED(n | map, BDRV_SECTOR_SIZE));
*pnum = n >> BDRV_SECTOR_BITS;
return ret | map;
return bdrv_common_block_status_above(bs, base, true, offset, bytes,
pnum, map, file);
}
int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,
int64_t *pnum, int64_t *map, BlockDriverState **file)
{
int64_t ret;
int n;
assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
assert(pnum);
/*
* The contract allows us to return pnum smaller than bytes, even
* if the next query would see the same status; we truncate the
* request to avoid overflowing the driver's 32-bit interface.
*/
bytes = MIN(bytes, BDRV_REQUEST_MAX_BYTES);
ret = bdrv_get_block_status_above(bs, backing_bs(bs),
offset >> BDRV_SECTOR_BITS,
bytes >> BDRV_SECTOR_BITS, &n, file);
if (ret < 0) {
assert(INT_MIN <= ret);
*pnum = 0;
return ret;
}
*pnum = n * BDRV_SECTOR_SIZE;
if (map) {
*map = ret & BDRV_BLOCK_OFFSET_MASK;
} else {
ret &= ~BDRV_BLOCK_OFFSET_VALID;
}
return ret & ~BDRV_BLOCK_OFFSET_MASK;
return bdrv_block_status_above(bs, backing_bs(bs),
offset, bytes, pnum, map, file);
}
int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,

18
block/mirror.c
View File

@ -328,7 +328,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
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 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
}
/* 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 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
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 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
} 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 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
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'");

30
block/qcow2.c
View File

@ -2974,8 +2974,8 @@ finish:
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 @@ static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
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 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
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 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
} 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;
}
}
}

8
include/block/block.h
View File

@ -425,11 +425,9 @@ bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
int bdrv_block_status(BlockDriverState *bs, int64_t offset,
int64_t bytes, int64_t *pnum, int64_t *map,
BlockDriverState **file);
int64_t bdrv_get_block_status_above(BlockDriverState *bs,
BlockDriverState *base,
int64_t sector_num,
int nb_sectors, int *pnum,
BlockDriverState **file);
int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
int64_t offset, int64_t bytes, int64_t *pnum,
int64_t *map, BlockDriverState **file);
int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
int64_t *pnum);
int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,

49
qemu-img.c
View File

@ -1226,7 +1226,7 @@ static int img_compare(int argc, char **argv)
BlockDriverState *bs1, *bs2;
int64_t total_sectors1, total_sectors2;
uint8_t *buf1 = NULL, *buf2 = NULL;
int pnum1, pnum2;
int64_t pnum1, pnum2;
int allocated1, allocated2;
int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */
bool progress = false, quiet = false, strict = false;
@ -1374,15 +1374,17 @@ static int img_compare(int argc, char **argv)
}
for (;;) {
int64_t status1, status2;
int status1, status2;
nb_sectors = sectors_to_process(total_sectors, sector_num);
if (nb_sectors <= 0) {
break;
}
status1 = bdrv_get_block_status_above(bs1, NULL, sector_num,
total_sectors1 - sector_num,
&pnum1, NULL);
status1 = bdrv_block_status_above(bs1, NULL,
sector_num * BDRV_SECTOR_SIZE,
(total_sectors1 - sector_num) *
BDRV_SECTOR_SIZE,
&pnum1, NULL, NULL);
if (status1 < 0) {
ret = 3;
error_report("Sector allocation test failed for %s", filename1);
@ -1390,25 +1392,29 @@ static int img_compare(int argc, char **argv)
}
allocated1 = status1 & BDRV_BLOCK_ALLOCATED;
status2 = bdrv_get_block_status_above(bs2, NULL, sector_num,
total_sectors2 - sector_num,
&pnum2, NULL);
status2 = bdrv_block_status_above(bs2, NULL,
sector_num * BDRV_SECTOR_SIZE,
(total_sectors2 - sector_num) *
BDRV_SECTOR_SIZE,
&pnum2, NULL, NULL);
if (status2 < 0) {
ret = 3;
error_report("Sector allocation test failed for %s", filename2);
goto out;
}
allocated2 = status2 & BDRV_BLOCK_ALLOCATED;
/* TODO: Relax this once comparison is byte-based, and we no longer
* have to worry about sector alignment */
assert(QEMU_IS_ALIGNED(pnum1 | pnum2, BDRV_SECTOR_SIZE));
if (pnum1) {
nb_sectors = MIN(nb_sectors, pnum1);
nb_sectors = MIN(nb_sectors, pnum1 >> BDRV_SECTOR_BITS);
}
if (pnum2) {
nb_sectors = MIN(nb_sectors, pnum2);
nb_sectors = MIN(nb_sectors, pnum2 >> BDRV_SECTOR_BITS);
}
if (strict) {
if ((status1 & ~BDRV_BLOCK_OFFSET_MASK) !=
(status2 & ~BDRV_BLOCK_OFFSET_MASK)) {
if (status1 != status2) {
ret = 1;
qprintf(quiet, "Strict mode: Offset %" PRId64
" block status mismatch!\n",
@ -1417,7 +1423,7 @@ static int img_compare(int argc, char **argv)
}
}
if ((status1 & BDRV_BLOCK_ZERO) && (status2 & BDRV_BLOCK_ZERO)) {
nb_sectors = MIN(pnum1, pnum2);
nb_sectors = DIV_ROUND_UP(MIN(pnum1, pnum2), BDRV_SECTOR_SIZE);
} else if (allocated1 == allocated2) {
if (allocated1) {
ret = blk_pread(blk1, sector_num << BDRV_SECTOR_BITS, buf1,
@ -1589,8 +1595,8 @@ static void convert_select_part(ImgConvertState *s, int64_t sector_num,
static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
{
int64_t ret, src_cur_offset;
int n, src_cur;
int64_t src_cur_offset;
int ret, n, src_cur;
convert_select_part(s, sector_num, &src_cur, &src_cur_offset);
@ -1598,23 +1604,24 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
n = MIN(s->total_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
if (s->sector_next_status <= sector_num) {
int64_t count = n * BDRV_SECTOR_SIZE;
if (s->target_has_backing) {
int64_t count = n * BDRV_SECTOR_SIZE;
ret = bdrv_block_status(blk_bs(s->src[src_cur]),
(sector_num - src_cur_offset) *
BDRV_SECTOR_SIZE,
count, &count, NULL, NULL);
assert(ret < 0 || QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
n = count >> BDRV_SECTOR_BITS;
} else {
ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,
sector_num - src_cur_offset,
n, &n, NULL);
ret = bdrv_block_status_above(blk_bs(s->src[src_cur]), NULL,
(sector_num - src_cur_offset) *
BDRV_SECTOR_SIZE,
count, &count, NULL, NULL);
}
if (ret < 0) {
return ret;
}
n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
if (ret & BDRV_BLOCK_ZERO) {
s->status = BLK_ZERO;