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block/io: support int64_t bytes in bdrv_aligned_pwritev()

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We are generally moving to int64_t for both offset and bytes parameters
on all io paths.

Main motivation is realization of 64-bit write_zeroes operation for
fast zeroing large disk chunks, up to the whole disk.

We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).

So, prepare bdrv_aligned_pwritev() now and convert the dependencies:
bdrv_co_write_req_prepare() and bdrv_co_write_req_finish() to signed
type bytes.

Conversion of bdrv_co_write_req_prepare() and
bdrv_co_write_req_finish() is definitely safe, as all requests in
block/io must not overflow BDRV_MAX_LENGTH. Still add assertions.

For bdrv_aligned_pwritev() 'bytes' type is widened, so callers are
safe. Let's check usage of the parameter inside the function.

Passing to bdrv_co_write_req_prepare() and bdrv_co_write_req_finish()
is OK.

Passing to qemu_iovec_* is OK after new assertion. All other callees
are already updated to int64_t.

Checking alignment is not changed, offset + bytes and qiov_offset +
bytes calculations are safe (thanks to new assertions).

max_transfer is kept to be int for now. It has a default of INT_MAX
here, and some drivers may rely on it. It's to be refactored later.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-12-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2020-12-11 21:39:29 +03:00 committed by Eric Blake
parent 5ae07b1410
commit fcfd9ade68
1 changed files with 13 additions and 8 deletions
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21
block/io.c
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@ -1932,11 +1932,12 @@ fail:
}
static inline int coroutine_fn
bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes,
bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, int64_t bytes,
BdrvTrackedRequest *req, int flags)
{
BlockDriverState *bs = child->bs;
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
bdrv_check_request(offset, bytes, &error_abort);
if (bs->read_only) {
return -EPERM;
@ -1963,7 +1964,8 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes,
assert(req->overlap_offset <= offset);
assert(offset + bytes <= req->overlap_offset + req->overlap_bytes);
assert(end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE);
assert(offset + bytes <= bs->total_sectors * BDRV_SECTOR_SIZE ||
child->perm & BLK_PERM_RESIZE);
switch (req->type) {
case BDRV_TRACKED_WRITE:
@ -1984,12 +1986,14 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes,
}
static inline void coroutine_fn
bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, int64_t bytes,
BdrvTrackedRequest *req, int ret)
{
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
BlockDriverState *bs = child->bs;
bdrv_check_request(offset, bytes, &error_abort);
qatomic_inc(&bs->write_gen);
/*
@ -2026,16 +2030,18 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
* after possibly fragmenting it.
*/
static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
BdrvTrackedRequest *req, int64_t offset, int64_t bytes,
int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
{
BlockDriverState *bs = child->bs;
BlockDriver *drv = bs->drv;
int ret;
uint64_t bytes_remaining = bytes;
int64_t bytes_remaining = bytes;
int max_transfer;
bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
if (!drv) {
return -ENOMEDIUM;
}
@ -2047,7 +2053,6 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
assert(is_power_of_2(align));
assert((offset & (align - 1)) == 0);
assert((bytes & (align - 1)) == 0);
assert(!qiov || qiov_offset + bytes <= qiov->size);
max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
align);
@ -2146,7 +2151,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
assert(!bytes || (offset & (align - 1)) == 0);
if (bytes >= align) {
/* Write the aligned part in the middle. */
uint64_t aligned_bytes = bytes & ~(align - 1);
int64_t aligned_bytes = bytes & ~(align - 1);
ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
NULL, 0, flags);
if (ret < 0) {