blkdebug: Sanity check block layer guarantees

Commits 04ed95f4 and 1a62d0ac updated the block layer to auto-fragment
any I/O to fit within device boundaries. Additionally, when using a
minimum alignment of 4k, we want to ensure the block layer does proper
read-modify-write rather than requesting I/O on a slice of a sector.
Let's enforce that the contract is obeyed when using blkdebug.  For
now, blkdebug only allows alignment overrides, and just inherits other
limits from whatever device it is wrapping, but a future patch will
further enhance things.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170429191419.30051-5-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Eric Blake 2017-04-29 14:14:14 -05:00 committed by Max Reitz
parent 6f3c90af3c
commit e0ef439588

View file

@ -429,6 +429,13 @@ blkdebug_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
BDRVBlkdebugState *s = bs->opaque;
BlkdebugRule *rule = NULL;
/* Sanity check block layer guarantees */
assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
if (bs->bl.max_transfer) {
assert(bytes <= bs->bl.max_transfer);
}
QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
uint64_t inject_offset = rule->options.inject.offset;
@ -453,6 +460,13 @@ blkdebug_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
BDRVBlkdebugState *s = bs->opaque;
BlkdebugRule *rule = NULL;
/* Sanity check block layer guarantees */
assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
if (bs->bl.max_transfer) {
assert(bytes <= bs->bl.max_transfer);
}
QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
uint64_t inject_offset = rule->options.inject.offset;