lkml.org 
[lkml]   [2014]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 2/4] fs: add fadvise file_operation
Date
Christoph Hellwig <hch@infradead.org> writes:

> On Sat, Oct 18, 2014 at 07:21:26PM +0400, Dmitry Monakhov wrote:
>> sys_fadvise result in direct f_mode modification, which may be not
>> suitable for some unusual filesytems where file mode invariant is more
>> complex. In order to support such filesystems we have to delegate fadvise
>> logic to filesystem layer.
>
> Is there a real use case for it? So for it seems mostly about ecryptfs,
> and even that use is lacking a proper explanation.
Fairly to say original issue was with vzfs (COW stack filesystem for
containers from openvz). As far as I understand direct analog is
unionfs. We asserted v_file->mode == lower_file->f_mode, but
fadvise (POSIX_FADV_{RANDOM,RANDOM,SEQUENTIAL})changes v_file->mode directly.
>
> Also fadvice and set_flags seem entirely unrelated, I don't understand
> why you're throwing fadvice in thise series.
It has semantic relation. Both methods manipulate filp->XXX internals directly
No problem I can split this to separate patch set.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2014-10-21 10:41    [W:2.689 / U:0.000 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site