Re: Fc cap revoke in Ceph-fuse

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Sep 24, 2020 at 11:07 AM Xiaoxi Chen <superdebuger@xxxxxxxxx> wrote:
>
> Hi zheng,
>       We are seeing inconsistent among clients ones one client update a file(by scp), some of the node see new contents but some of the nodes don't.   The inconsistent can last 30mins to a few hours and fix by its own.  I think it should because some of the node not dropping the page cache properly.
>      Looking into the code I see when Fc cap revoke,  fuse client drop objectcache , queue a task to finisher thread to do fuse_lowlevel_notify_inval_inode,  then ack the cap revoke.  So seems there is a window between the cap-revoke-ack , and the final fuse_lowlevel_notify_inval_inode finished, in this window page cache still valid and user can read stale data.    Though it is strange that the window can be that large(no pg issue during the window).
>      Could you please confirm if this is the real problems and why it is implemented in this way?
>

yes, it's real problem.  fuse_lowlevel_notify_inval_inode() does not
prevent client add page cache later. If there are multiple fuse
clients read/modify same file, you'd better to set
fuse_disable_pagecache option to true.

> -xiaoxi
_______________________________________________
Dev mailing list -- dev@xxxxxxx
To unsubscribe send an email to dev-leave@xxxxxxx



[Index of Archives]     [CEPH Users]     [Ceph Devel]     [Ceph Large]     [Information on CEPH]     [Linux BTRFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux