Re: [PATCH v2] fuse: use newer inode info when writeback cache is enabled

[Miklos Szeredi <miklos@szeredi.hu>]

On Thu, 24 Jun 2021 at 09:42, Fengnan Chang <changfengnan@vivo.com> wrote:
>
> Hi Miklos:
>
> Thank you for the information, I have been able to reproduce the problem.
>
> The new version of the patch as below. Previous fsx test is pass now.
> Need do more test, Can you help to test new patch? or send me your test
> case, I will test this.
>
> Here is my test case, and is the problem this patch is trying to solve.
> Case A:
> mkdir /tmp/test
> passthrough_ll -ocache=always,writeback /mnt/test/
> echo "11111" > /tmp/test/fsx
> ls -l /mnt/test/tmp/test/
> echo "2222" >> /tmp/test/fsx
> ls -l /mnt/test/tmp/test/
>
> Case B:
> mkdir /tmp/test
> passthrough_ll -ocache=always,writeback /mnt/test/
> passthrough_ll -ocache=always,writeback /mnt/test2/
> echo "11111" > /tmp/test/fsx
> ls -l /mnt/test/tmp/test/
> ls -l /mnt/test2/tmp/test/
> echo "222" >> /mnt/test/tmp/test/fsx
> ls -l /mnt/test/tmp/test/
> ls -l /mnt/test2/tmp/test/

Both these testcases have the "cache=always" option, which means:
cached values (both data and metadata) are always valid; i.e. changes
will be made only through this client and not through some other
channel (like the backing filesystem or another instance).

Why is "cache=always" used?

Thanks,
Miklos