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From: Christoph Hellwig <hch@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org,
	linux-nfs@vger.kernel.org, samba-technical@lists.samba.org,
	linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 1/6] statx: Add a system call to make enhanced file info available
Date: Thu, 12 May 2016 02:12:49 -0700	[thread overview]
Message-ID: <20160512091249.GB22420@infradead.org> (raw)
In-Reply-To: <7963.1462869823@warthog.procyon.org.uk>

On Tue, May 10, 2016 at 09:43:43AM +0100, David Howells wrote:
> Christoph Hellwig <hch@infradead.org> wrote:
> 
> > All of these are easily available.  But why special case them so that
> > userspace must not ask for them?  This makes an otherwise totally
> > regular interface special now.  Note that filesystems could always fill
> > it out anyway and set it in the return mask.
> 
> Because it would be a waste of bits in the mask.  Is there a point in having
> bits that are always going to be set unconditionally when we can just
> *document* that these few fields are always going to be set.

And what exaxtly is the cost of these bits?

> So yes, you can look on it as there are special cases.  However, if I can drop
> stat emulation support, everything resolves down to the following classes:
> 
>  (1) Stuff that's unconditional: st_dev, st_blksize, st_information (maybe).
> 
>  (2) st_mode & S_IFMT.  Unconditional or conditional?  I'm not sure.
> 
>  (3) Stuff that's conditional: st_mode & ~S_IFMT, st_rdev, st_ino, ...
>      Basically everything else.

If we at least go down to one set of conditional and one optional that's
at least much better than what we currently have.

  reply	other threads:[~2016-05-12  9:12 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-29 12:57 [RFC][PATCH 0/6] Enhanced file stat system call David Howells
2016-04-29 12:57 ` [PATCH 1/6] statx: Add a system call to make enhanced file info available David Howells
2016-05-02 22:46   ` Andreas Dilger
2016-05-02 22:46     ` Andreas Dilger
2016-05-03 15:53   ` David Howells
2016-05-04 22:56   ` Dave Chinner
2016-05-05  0:09     ` NeilBrown
2016-05-05  0:09       ` NeilBrown
2016-05-05 19:48       ` Jeff Layton
2016-05-06 18:07         ` J. Bruce Fields
2016-05-06 18:07           ` J. Bruce Fields
2016-05-05 20:04       ` David Howells
2016-05-05 20:04         ` David Howells
2016-05-06  1:39         ` Dave Chinner
2016-05-06  1:39           ` Dave Chinner
2016-05-06  1:39           ` Dave Chinner
2016-05-06 18:29     ` J. Bruce Fields
2016-05-09  1:45       ` Dave Chinner
2016-05-09  2:46         ` J. Bruce Fields
2016-05-04 23:56   ` NeilBrown
2016-05-08  8:35   ` Christoph Hellwig
2016-05-08  8:35     ` Christoph Hellwig
2016-05-09 12:02     ` Jeff Layton
2016-05-09 12:02       ` Jeff Layton
2016-05-10  7:00       ` Christoph Hellwig
2016-05-10  7:00         ` Christoph Hellwig
2016-05-10 13:21         ` Jeff Layton
2016-05-10 13:21           ` Jeff Layton
2016-05-09 12:57   ` David Howells
2016-05-09 12:57     ` David Howells
2016-05-09 13:23     ` Trond Myklebust
2016-05-09 13:23       ` Trond Myklebust
2016-05-09 13:23       ` Trond Myklebust
2016-05-10  7:04     ` Christoph Hellwig
2016-05-10  8:25     ` David Howells
2016-05-12  9:11       ` Christoph Hellwig
2016-05-13 15:28         ` Arnd Bergmann
2016-05-13 15:28           ` Arnd Bergmann
2016-05-23  8:22           ` Christoph Hellwig
2016-05-23  9:33           ` David Howells
2016-05-18 10:55         ` David Howells
2016-05-09 13:00   ` David Howells
2016-05-09 13:00     ` David Howells
2016-05-09 13:38   ` David Howells
2016-05-10  7:08     ` Christoph Hellwig
2016-05-10  8:43     ` David Howells
2016-05-12  9:12       ` Christoph Hellwig [this message]
2016-05-09 13:40   ` David Howells
2016-04-29 12:57 ` [PATCH 2/6] statx: AFS: Return enhanced file attributes David Howells
2016-04-29 12:57 ` [PATCH 3/6] statx: Ext4: " David Howells
2016-05-02 22:48   ` Andreas Dilger
2016-05-03 20:24   ` David Howells
2016-05-03 20:24     ` David Howells
2016-05-08  8:38   ` Christoph Hellwig
2016-05-08  8:38     ` Christoph Hellwig
2016-04-29 12:58 ` [PATCH 4/6] statx: NFS: " David Howells
2016-05-02 22:48   ` Andreas Dilger
2016-04-29 12:58 ` [PATCH 5/6] statx: Make windows attributes available for CIFS, NTFS and FAT to use David Howells
2016-05-02 22:52   ` Andreas Dilger
2016-10-03 21:03     ` Steve French
2016-10-03 21:03       ` Steve French
2016-05-03 20:23   ` David Howells
2016-05-08  8:39   ` Christoph Hellwig
2016-05-08  8:39     ` Christoph Hellwig
2016-04-29 12:58 ` [PATCH 6/6] statx: CIFS: Return enhanced attributes David Howells
2016-04-30 21:05 ` [RFC][PATCH 0/6] Enhanced file stat system call Jeff Layton
2016-04-30 21:05   ` Jeff Layton
2016-05-04 13:46 ` Arnd Bergmann
2016-05-04 13:46   ` Arnd Bergmann
2016-05-05 22:54   ` Steve French
2016-05-06  2:00     ` Steve French
2016-05-09 13:09       ` Arnd Bergmann
2016-05-09 13:09         ` Arnd Bergmann
2016-05-13 14:28         ` Richard Sharpe
2016-05-13 14:28           ` Richard Sharpe
2016-05-13 15:08           ` Arnd Bergmann

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