Re: [Qemu-devel] [PATCH] 9pfs: don't ignore O_DIRECT flag in the 9pfs server

2017-11-27 Thread Greg Kurz
On Tue, 21 Nov 2017 11:28:29 +0800 jiangyiwen wrote: > On 2017/11/20 18:13, Greg Kurz wrote: > > On Mon, 20 Nov 2017 13:48:59 +0800 > > jiangyiwen wrote: > > > >> Now v9fs in linux has already supported O_DIRECT(v9fs_direct_IO), > >> when guest user open file with O_DIRECT flag and return suc

Re: [Qemu-devel] [PATCH] 9pfs: don't ignore O_DIRECT flag in the 9pfs server

2017-11-20 Thread jiangyiwen
On 2017/11/20 18:13, Greg Kurz wrote: > On Mon, 20 Nov 2017 13:48:59 +0800 > jiangyiwen wrote: > >> Now v9fs in linux has already supported O_DIRECT(v9fs_direct_IO), >> when guest user open file with O_DIRECT flag and return success, >> so user hopes data doesn't pass through page cache, but 9pfs

Re: [Qemu-devel] [PATCH] 9pfs: don't ignore O_DIRECT flag in the 9pfs server

2017-11-20 Thread Greg Kurz
On Mon, 20 Nov 2017 13:48:59 +0800 jiangyiwen wrote: > Now v9fs in linux has already supported O_DIRECT(v9fs_direct_IO), > when guest user open file with O_DIRECT flag and return success, > so user hopes data doesn't pass through page cache, but 9pfs in > qemu ignore direct disk access and use ho

[Qemu-devel] [PATCH] 9pfs: don't ignore O_DIRECT flag in the 9pfs server

2017-11-19 Thread jiangyiwen
Now v9fs in linux has already supported O_DIRECT(v9fs_direct_IO), when guest user open file with O_DIRECT flag and return success, so user hopes data doesn't pass through page cache, but 9pfs in qemu ignore direct disk access and use host page cache, it is not match to DIRECT_IO semantic, so we sho