Re: [Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives
On 07/20/10 19:19, Markus Armbruster wrote: > Jes Sorensen writes: > >> On 07/20/10 18:35, David S. Ahern wrote: >>> On 07/20/10 10:09, jes.soren...@redhat.com wrote: >>> If a cdrom is added via the monitor this would abruptly terminate the VM >>> - which is not good. >> >> True, but this would only happen if the user explicitly marks it >> cache=none which is not the default value for a new drive, so it would >> be a corner case. > > Why not return -ENOTSUP? Good point, just posted v3 of the patch that does this instead of exit() Jes
Re: [Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives
Jes Sorensen writes:
> On 07/20/10 18:35, David S. Ahern wrote:
>> On 07/20/10 10:09, jes.soren...@redhat.com wrote:
>>> diff --git a/block/raw-posix.c b/block/raw-posix.c
>>> index 291699f..1b840c4 100644
>>> --- a/block/raw-posix.c
>>> +++ b/block/raw-posix.c
>>> @@ -1139,6 +1139,11 @@ static int cdrom_open(BlockDriverState *bs, const
>>> char *filename, int flags)
>>> BDRVRawState *s = bs->opaque;
>>>
>>> s->type = FTYPE_CD;
>>> +if (flags & BDRV_O_NOCACHE) {
>>> +fprintf(stderr, "O_DIRECT (cache=none) for CDROM/DVD device (%s) "
>>> +"is unsupported\n", filename);
>>> +exit(1);
>>> +}
>>
>> If a cdrom is added via the monitor this would abruptly terminate the VM
>> - which is not good.
>
> True, but this would only happen if the user explicitly marks it
> cache=none which is not the default value for a new drive, so it would
> be a corner case.
Why not return -ENOTSUP?
Re: [Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives
On 07/20/10 18:35, David S. Ahern wrote:
> On 07/20/10 10:09, jes.soren...@redhat.com wrote:
>> diff --git a/block/raw-posix.c b/block/raw-posix.c
>> index 291699f..1b840c4 100644
>> --- a/block/raw-posix.c
>> +++ b/block/raw-posix.c
>> @@ -1139,6 +1139,11 @@ static int cdrom_open(BlockDriverState *bs, const
>> char *filename, int flags)
>> BDRVRawState *s = bs->opaque;
>>
>> s->type = FTYPE_CD;
>> +if (flags & BDRV_O_NOCACHE) {
>> +fprintf(stderr, "O_DIRECT (cache=none) for CDROM/DVD device (%s) "
>> +"is unsupported\n", filename);
>> +exit(1);
>> +}
>
> If a cdrom is added via the monitor this would abruptly terminate the VM
> - which is not good.
True, but this would only happen if the user explicitly marks it
cache=none which is not the default value for a new drive, so it would
be a corner case.
Cheers,
Jes
Re: [Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives
On 07/20/10 10:09, jes.soren...@redhat.com wrote:
> From: Jes Sorensen
>
> O_DIRECT (cache=none) requires sector alignment, however the physical
> sector size of CDROM/DVD drives is 2048, as opposed to most disk
> devices which use 512. QEMU is hard coding 512 all over the place, so
> allowing O_DIRECT for CDROM/DVD devices does not work. Exit with an
> error!
>
> Signed-off-by: Jes Sorensen
> ---
> block/raw-posix.c |5 +
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 291699f..1b840c4 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1139,6 +1139,11 @@ static int cdrom_open(BlockDriverState *bs, const char
> *filename, int flags)
> BDRVRawState *s = bs->opaque;
>
> s->type = FTYPE_CD;
> +if (flags & BDRV_O_NOCACHE) {
> +fprintf(stderr, "O_DIRECT (cache=none) for CDROM/DVD device (%s) "
> +"is unsupported\n", filename);
> +exit(1);
> +}
If a cdrom is added via the monitor this would abruptly terminate the VM
- which is not good.
David
>
> /* open will not fail even if no CD is inserted, so add O_NONBLOCK */
> return raw_open_common(bs, filename, flags, O_NONBLOCK);
[Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives
From: Jes Sorensen
O_DIRECT (cache=none) requires sector alignment, however the physical
sector size of CDROM/DVD drives is 2048, as opposed to most disk
devices which use 512. QEMU is hard coding 512 all over the place, so
allowing O_DIRECT for CDROM/DVD devices does not work. Exit with an
error!
Signed-off-by: Jes Sorensen
---
block/raw-posix.c |5 +
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 291699f..1b840c4 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1139,6 +1139,11 @@ static int cdrom_open(BlockDriverState *bs, const char
*filename, int flags)
BDRVRawState *s = bs->opaque;
s->type = FTYPE_CD;
+if (flags & BDRV_O_NOCACHE) {
+fprintf(stderr, "O_DIRECT (cache=none) for CDROM/DVD device (%s) "
+"is unsupported\n", filename);
+exit(1);
+}
/* open will not fail even if no CD is inserted, so add O_NONBLOCK */
return raw_open_common(bs, filename, flags, O_NONBLOCK);
--
1.7.1.1
