[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom |
Date: |
Thu, 02 Jul 2015 15:58:28 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 02/07/2015 15:47, Paolo Bonzini wrote:
>
>
> On 02/07/2015 14:24, Laurent Vivier wrote:
>>
>> #ifdef __FreeBSD__
>> if (S_ISCHR(st.st_mode)) {
>> /*
>> * The file is a char device (disk), which on FreeBSD isn't behind
>> * a pager, so force all requests to be aligned. This is needed
>> * so QEMU makes sure all IO operations on the device are aligned
>> * to sector size, or else FreeBSD will reject them with EINVAL.
>> */
>> s->needs_alignment = true;
>> }
>> #endif
>
> So on FreeBSD and Apple /dev/r* is the equivalent of BDRV_O_NO_CACHE?
This is what I understand (MacOS is a derivative from FreeBSD)
https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/hdiutil.1.html
DEVICE SPECIAL FILES
Since any /dev entry can be treated as a raw disk image, it is worth
noting which devices can be accessed when and how. /dev/rdisk nodes are
character-special devices, but are "raw" in the BSD sense and force
block-aligned I/O. They are closer to the physical disk than the buffer
cache. /dev/disk nodes, on the other hand, are buffered block-special
devices and are used primarily by the kernel's filesystem code.
Laurent
- [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Programmingkid, 2015/07/01
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, M A, 2015/07/01
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Paolo Bonzini, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Stefan Hajnoczi, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Laurent Vivier, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Paolo Bonzini, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom,
Laurent Vivier <=
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Paolo Bonzini, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Laurent Vivier, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Paolo Bonzini, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Laurent Vivier, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Programmingkid, 2015/07/02
- Re: [Qemu-devel] [PATCH v2] raw-posix.c: remove raw device access for cdrom, Programmingkid, 2015/07/02
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Kevin Wolf, 2015/07/08
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Laurent Vivier, 2015/07/08
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Kevin Wolf, 2015/07/08
- Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom, Programmingkid, 2015/07/08