diff options
| -rw-r--r-- | block/io.c | 28 | ||||
| -rw-r--r-- | hw/core/machine.c | 3 |
2 files changed, 29 insertions, 2 deletions
diff --git a/block/io.c b/block/io.c index 1eb2b2bddc..7e4cb74cf4 100644 --- a/block/io.c +++ b/block/io.c @@ -1565,10 +1565,12 @@ static bool bdrv_init_padding(BlockDriverState *bs, pad->tail = align - pad->tail; } - if ((!pad->head && !pad->tail) || !bytes) { + if (!pad->head && !pad->tail) { return false; } + assert(bytes); /* Nothing good in aligning zero-length requests */ + sum = pad->head + bytes + pad->tail; pad->buf_len = (sum > align && pad->head && pad->tail) ? 2 * align : align; pad->buf = qemu_blockalign(bs, pad->buf_len); @@ -1706,6 +1708,18 @@ int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, return ret; } + if (bytes == 0 && !QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)) { + /* + * Aligning zero request is nonsense. Even if driver has special meaning + * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass + * it to driver due to request_alignment. + * + * Still, no reason to return an error if someone do unaligned + * zero-length read occasionally. + */ + return 0; + } + bdrv_inc_in_flight(bs); /* Don't do copy-on-read if we read data before write operation */ @@ -2116,6 +2130,18 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, return -ENOTSUP; } + if (bytes == 0 && !QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)) { + /* + * Aligning zero request is nonsense. Even if driver has special meaning + * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass + * it to driver due to request_alignment. + * + * Still, no reason to return an error if someone do unaligned + * zero-length write occasionally. + */ + return 0; + } + bdrv_inc_in_flight(bs); /* * Align write if necessary by performing a read-modify-write cycle. diff --git a/hw/core/machine.c b/hw/core/machine.c index 3e288bfceb..d8e30e4895 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -148,7 +148,8 @@ GlobalProperty hw_compat_2_5[] = { const size_t hw_compat_2_5_len = G_N_ELEMENTS(hw_compat_2_5); GlobalProperty hw_compat_2_4[] = { - { "virtio-blk-device", "scsi", "true" }, + /* Optional because the 'scsi' property is Linux-only */ + { "virtio-blk-device", "scsi", "true", .optional = true }, { "e1000", "extra_mac_registers", "off" }, { "virtio-pci", "x-disable-pcie", "on" }, { "virtio-pci", "migrate-extra", "off" }, |