Re: [PATCH v2 1/5] fat: allocate persistent inode numbers

From: Namjae Jeon
Date: Thu Sep 13 2012 - 10:24:23 EST


2012/9/13, OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>:
> "J. Bruce Fields" <bfields@xxxxxxxxxxxx> writes:
>
>>> >> Grepping around... Documentation/sysctl/vm.txt mentions a
>>> >> vfs_cache_pressure parameter.
>>> >> Yeah. And dirty hack will be possible to adjust sb->s_shrink.batch.
>>> > I am worrying if it could lead to OOM condition on embedded
>>> > system(short memory(DRAM) and support 3TB HDD disk of big size.)
>>> >
>>> > Please let me know if any issues or queries.
>>>
>>> So, now I think stable inode number may be useful if there are users of
>>> it. And I guess those functionality is no collisions with -mm. And I
>>> suppose we can add two modes for "nfs" option (e.g. nfs=1 and nfs=2).
>>>
>>> If nfs=1, works like current -mm without no limited operations.
>>
>> Apologies, I haven't been following the conversation carefully: remind
>> me what "works like current -mm" means?
>
> Current -mm means the best-effort work only if inode cache is not
> evicted. I.e. if there is no inode cache anymore on server, server
> would return ESTALE. So I guess the behavior would not be stable
> relatively.
Hi OGAWA.
Sorry for late response.
Okay, I will resend patchset include your suggeston.(-o nfs=2)
Do you mind adding busy list patch to avoid unlink issue ?
And in case of rename, FAT retrun EBUSY while opening file.
We can limit only rename.
Let me know your opinion.

Thanks OGAWA!

>
> Thanks.
>
>>> If nfs=2, try to make stable FH and limit some operations
>>>
>>> (option name doesn't matter here.)
>>>
>>> Does this work fine?
> --
> OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
>
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