On 29 Aug 2024, at 5:13, Yafang Shao wrote:
> In our production environment, we noticed that some files are missing when
> running the ls command in an NFS directory. However, we can still
> successfully cd into the missing directories. This issue can be illustrated
> as follows:
>
> $ cd nfs
> $ ls
> a b c e f <<<< 'd' is missing
> $ cd d <<<< success
>
> I verified the issue with the latest upstream kernel, and it still
> persists. Further analysis reveals that files go missing when the dtsize is
> expanded. The default dtsize was reduced from 1MB to 4KB in commit
> 580f236737d1 ("NFS: Adjust the amount of readahead performed by NFS readdir").
> After restoring the default size to 1MB, the issue disappears. I also tried
> setting the default size to 8KB, and the issue similarly disappears.
>
> Upon further analysis, it appears that there is a bad entry being decoded
> in nfs_readdir_entry_decode(). When a bad entry is encountered, the
> decoding process breaks without handling the error. We should revert the
> bad entry in such cases. After implementing this change, the issue is
> resolved.
It seems like you're trying to handle a server bug of some sort. Have you
been able to look at a wire capture to determine why there's a bad entry?
Ben
