| Message ID | 20161202192223.15153-2-eblake@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 02.12.2016 20:22, Eric Blake wrote: > 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> > > --- > v3: rebase to byte-based interfaces > v2: new patch > --- > block/blkdebug.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) Reviewed-by: Max Reitz <mreitz@redhat.com>
Am 02.12.2016 um 20:22 hat Eric Blake geschrieben: > 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>
diff --git a/block/blkdebug.c b/block/blkdebug.c index acccf85..37094a2 100644 --- a/block/blkdebug.c +++ b/block/blkdebug.c @@ -438,6 +438,13 @@ 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; @@ -462,6 +469,13 @@ 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;
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> --- v3: rebase to byte-based interfaces v2: new patch --- block/blkdebug.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)