On Thu, 1 Oct 2015, Constantine Peresypkin wrote:
>
> The question is: can I force it to always use unstable? Or how can I debug why FILE_SYNC is always sent in my case?
No, I don't believe you can. You can use systemtap, or turn up the nfs
debugging.
I don't think FILE_SYNC will always be sent. It depends upon how you are
doing IO. What are you using to test?
Try something like this on a mount with wsize=4096. It should get you four
unstable writes, and eventually a COMMIT:
#define TPATH "/mnt/fedora/tmp/"
#define SIZE 4096*4
#define CHARS "I love when strings are 32 chars"
int main(void *argc) {
int pos, filp_foo;
void *foo_addr;
unlink(TPATH "foo");
filp_foo = open(TPATH "foo", O_RDWR|O_CREAT, S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH);
ftruncate(filp_foo, SIZE);
foo_addr = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, filp_foo, 0);
for (pos = 0; pos < SIZE; pos += strlen(CHARS))
strcpy(foo_addr + pos, CHARS);
close(filp_foo);
}
Ben
>
> On Oct 1, 2015 12:32 PM, "Benjamin Coddington" <bcodding@xxxxxxxxxx> wrote:
> On Thu, 1 Oct 2015, Constantine Peresypkin wrote:
>
> > Tried with various mount options (sync, async)
> > Looked into source code.
> > It seems like it will never be sent, client always assumes server can
> > do FILE_SYNC, and server cannot respond with anything else, if
> > implemented correctly.
> > But what we can do if the server is inherently unable to do FILE_SYNC
> > (eventual consistency, write reorder, etc.)?
>
> Hi Constantine, my linux client does unstable writes all the time.
> nfs_pgio_rpcsetup() default stable arg is NFS_UNSTABLE..
>
> Try doing a write larger than your mount's wsize parameter.
>
> Ben
>
>
>
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