graphic: 0.216
KVM: 0.154
semantic: 0.089
other: 0.088
files: 0.068
device: 0.068
PID: 0.063
debug: 0.058
vnc: 0.048
permissions: 0.033
performance: 0.033
network: 0.029
boot: 0.027
socket: 0.025
KVM: 0.548
debug: 0.239
files: 0.077
graphic: 0.040
other: 0.020
device: 0.014
PID: 0.012
performance: 0.010
semantic: 0.010
network: 0.009
socket: 0.009
boot: 0.005
vnc: 0.005
permissions: 0.004

editing the file when mount the file system using 9pfs. it will report fsync failed. 

 I have get a fsync error when I use the 9pfs on the kvm guest. it appears when I use vi editor and sysbench. I have not  found the reason yet. can you tell something about it?  the attache is the picture. and there is no any log which I can provide.

 My qemu version is qemu-kvm-0.13.0, and my  host  linux distributions is 2.6.32-431.el6.x86_64 and the guest vm is the same version which enable 9pfs and 9pnet support. I use the string of "mount -t 9p -o trans=virtio test_mount /tmp/shared/ -oversion=9p2000.L,posixacl" to get the file system.

resovled it, this is because in the kernel 2.6.32; the 9pfs doesn't implement the fsync function. just back port the code from higher version, can resolve it. 

like this patch

https://gitorious.org/linux-gemini/mainline/commit/7a4439c406c21b1e900ed497cec1a79d05b38c07



Closing, as this problem has been resolved according to the last comment.