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Re: [Qemu-devel] [PATCH] Disable O_DIRECT for physical CDROM/DVD drives
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] Disable O_DIRECT for physical CDROM/DVD drives |
Date: |
Tue, 20 Jul 2010 18:12:49 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 |
Am 20.07.2010 18:04, schrieb Jes Sorensen:
> On 07/20/10 17:40, Kevin Wolf wrote:
>>> diff --git a/block/raw-posix.c b/block/raw-posix.c
>>> index 291699f..0ea79b6 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, "Disabling unsupported O_DIRECT (cache=none) for "
>>> + "CDROM/DVD device (%s)\n", filename);
>>> + flags &= ~BDRV_O_NOCACHE;
>>> + }
>>
>> Good point. Just one detail: We should probably change bs->open_flags,
>> too, to keep things consistent.
>
> Thats effectively what my patch does. cdrom_open() calls
> raw_open_common() which has this part:
>
> /* Use O_DSYNC for write-through caching, no flags for write-back
> caching,
> * and O_DIRECT for no caching. */
> if ((bdrv_flags & BDRV_O_NOCACHE))
> s->open_flags |= O_DIRECT;
s and bs both have a field open_flags (and I think they share some more
field names, which has caused confusion more than once). I meant the bs
one here.
Kevin
Re: [Qemu-devel] Re: [PATCH] Disable O_DIRECT for physical CDROM/DVD drives, Kevin Wolf, 2010/07/20
Re: [Qemu-devel] [PATCH] Disable O_DIRECT for physical CDROM/DVD drives, Natalia Portillo, 2010/07/20