Since the raw format driver is just passing things through, we can
do byte-based read and write if the underlying protocol does
likewise.
There's one tricky part - if we probed the image format, we document
that we restrict operations on the initial sector. Rather than
trying to handle a read-modify-write on the first sector, it's
easiest to just include in our restrictions that partial writes to
the first sector are not permitted.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
block/raw_bsd.c | 35 +++++++++++++++++------------------
1 file changed, 17 insertions(+), 18 deletions(-)
diff --git a/block/raw_bsd.c b/block/raw_bsd.c
index 365c38a..a417d9a 100644
--- a/block/raw_bsd.c
+++ b/block/raw_bsd.c
@@ -50,32 +50,32 @@ static int raw_reopen_prepare(BDRVReopenState *reopen_state,
return 0;
}
-static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors, QEMUIOVector *qiov)
+static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
+ uint64_t bytes, QEMUIOVector *qiov,
+ int flags)
{
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
- return bdrv_co_readv(bs->file->bs, sector_num, nb_sectors, qiov);
+ return bdrv_co_preadv(bs->file->bs, offset, bytes, qiov, flags);
}
-static int coroutine_fn
-raw_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
- QEMUIOVector *qiov, int flags)
+static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
+ uint64_t bytes, QEMUIOVector *qiov,
+ int flags)
{
void *buf = NULL;
BlockDriver *drv;
QEMUIOVector local_qiov;
int ret;
- if (bs->probed && sector_num == 0) {
- /* As long as these conditions are true, we can't get partial writes to
- * the probe buffer and can just directly check the request. */
+ if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
+ /* Handling partial writes would be a pain - so we just
+ * require that the guest cannot write to the first sector
+ * without writing the entire sector */
QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
-
- if (nb_sectors == 0) {
- /* qemu_iovec_to_buf() would fail, but we want to return success
- * instead of -EINVAL in this case. */
- return 0;
+ if (offset != 0 || bytes < BLOCK_PROBE_BUF_SIZE) {
+ ret = -EINVAL;
+ goto fail;
}
buf = qemu_try_blockalign(bs->file->bs, 512);
@@ -105,8 +105,7 @@ raw_co_writev_flags(BlockDriverState *bs, int64_t
sector_num, int nb_sectors,
}
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
- ret = bdrv_co_pwritev(bs->file->bs, sector_num * BDRV_SECTOR_SIZE,
- nb_sectors * BDRV_SECTOR_SIZE, qiov, flags);
+ ret = bdrv_co_pwritev(bs->file->bs, offset, bytes, qiov, flags);
fail:
if (qiov == &local_qiov) {
@@ -240,8 +239,8 @@ BlockDriver bdrv_raw = {
.bdrv_open = &raw_open,
.bdrv_close = &raw_close,
.bdrv_create = &raw_create,
- .bdrv_co_readv = &raw_co_readv,
- .bdrv_co_writev_flags = &raw_co_writev_flags,
+ .bdrv_co_preadv = &raw_co_preadv,
+ .bdrv_co_pwritev = &raw_co_pwritev,
.bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
.bdrv_co_pdiscard = &raw_co_pdiscard,
.bdrv_co_get_block_status = &raw_co_get_block_status,
--
2.5.5
