From: "J. Bruce Fields" <bfields@fieldses.org>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Al Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Pavel Emelyanov <xemul@parallels.com>,
James Bottomley <jbottomley@parallels.com>,
Matthew Helsley <matt.helsley@gmail.com>
Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper
Date: Wed, 15 Aug 2012 18:06:23 -0400 [thread overview]
Message-ID: <20120815220622.GA28054@fieldses.org> (raw)
In-Reply-To: <20120815210237.GF25421@moon>
On Thu, Aug 16, 2012 at 01:02:37AM +0400, Cyrill Gorcunov wrote:
> On Wed, Aug 15, 2012 at 04:45:46PM -0400, J. Bruce Fields wrote:
> > On Wed, Aug 15, 2012 at 01:21:20PM +0400, Cyrill Gorcunov wrote:
> > > To provide fsnotify object inodes being watched without
> > > binding to alphabetical path we need to encode them with
> > > exportfs help. This patch adds a helper which operates
> > > with plain inodes directly.
> >
> > I don't get it--this seems like a really roundabout way to get inode and
> > generation number, if that's all you want.
>
> We can re-open the targets via filehandle on restore, this was the idea.
> All this series aimed to achieve the way to restore objects after checkpoit,
> thus we need to provide additional information which would be enough.
For this to work it'll need to be something you can pass to
open_by_handle_at, won't it?
> > On the other hand, if you want a real filehandle then wouldn't you want
> > to e.g. call the filesystem's ->encode_fh() if necessary, as
> > exportfs_encode_fh() does?
>
> Well, one of the problem I hit when I've been trying to use encode_fh
> is that every new implementation of encode_fh will require some size
> (even unknown) in buffer where encoded data pushed. Correct me please
> if I'm wrong. But with export_encode_inode_fh there is a small buffer
> with pretty known size needed on stack needed for printing data in
> fdinfo.
You can just give encode_fh a too-small data and let it fail if it's not
big enough.
(In practice I think everyone supports NFSv3 filehandles which have a
maximum size of 64 bytes.)
--b.
next prev parent reply other threads:[~2012-08-15 22:06 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-15 9:21 [patch 0/8] procfs, fdinfo updated Cyrill Gorcunov
2012-08-15 9:21 ` [patch 1/8] procfs: Move /proc/pid/fd[info] handling code to fd.[ch] Cyrill Gorcunov
2012-08-15 9:21 ` [patch 2/8] procfs: Convert /proc/pid/fdinfo/ handling routines to seq-file Cyrill Gorcunov
2012-08-15 9:21 ` [patch 3/8] procfs: Add ability to plug in auxiliary fdinfo providers Cyrill Gorcunov
2012-08-15 21:16 ` Al Viro
2012-08-15 21:31 ` Cyrill Gorcunov
2012-08-15 21:29 ` Al Viro
2012-08-15 21:34 ` Cyrill Gorcunov
2012-08-16 10:58 ` Cyrill Gorcunov
2012-08-15 9:21 ` [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper Cyrill Gorcunov
2012-08-15 20:45 ` J. Bruce Fields
2012-08-15 21:02 ` Cyrill Gorcunov
2012-08-15 22:06 ` J. Bruce Fields [this message]
2012-08-16 6:24 ` Cyrill Gorcunov
2012-08-16 12:38 ` Cyrill Gorcunov
2012-08-16 12:47 ` J. Bruce Fields
2012-08-16 13:16 ` Cyrill Gorcunov
2012-08-16 14:57 ` Cyrill Gorcunov
2012-08-16 15:05 ` Al Viro
2012-08-16 15:09 ` Cyrill Gorcunov
2012-08-16 13:43 ` Al Viro
2012-08-16 13:47 ` Pavel Emelyanov
2012-08-16 13:50 ` Al Viro
2012-08-16 13:53 ` Pavel Emelyanov
2012-08-16 13:54 ` Cyrill Gorcunov
2012-08-16 14:03 ` James Bottomley
2012-08-16 14:13 ` Pavel Emelyanov
2012-08-16 14:15 ` Cyrill Gorcunov
2012-08-16 14:41 ` Al Viro
2012-08-16 14:48 ` Cyrill Gorcunov
2012-08-16 14:54 ` J. Bruce Fields
2012-08-16 14:55 ` Al Viro
2012-08-16 15:06 ` Pavel Emelyanov
2012-08-16 15:35 ` Cyrill Gorcunov
2012-08-16 15:07 ` Cyrill Gorcunov
2012-08-17 20:58 ` Eric W. Biederman
2012-08-16 13:48 ` Al Viro
2012-08-20 14:19 ` Aneesh Kumar K.V
2012-08-20 16:33 ` Cyrill Gorcunov
2012-08-20 18:32 ` J. Bruce Fields
2012-08-20 19:06 ` Cyrill Gorcunov
2012-08-20 19:32 ` J. Bruce Fields
2012-08-20 19:40 ` Cyrill Gorcunov
2012-08-21 9:18 ` Pavel Emelyanov
2012-08-21 10:42 ` Aneesh Kumar K.V
2012-08-21 10:49 ` Pavel Emelyanov
2012-08-21 10:54 ` Cyrill Gorcunov
2012-08-21 11:09 ` Pavel Emelyanov
2012-08-21 12:11 ` J. Bruce Fields
2012-08-21 12:22 ` Pavel Emelyanov
2012-08-21 12:29 ` J. Bruce Fields
2012-08-21 12:40 ` Pavel Emelyanov
2012-08-21 12:51 ` Boaz Harrosh
2012-08-21 12:59 ` Pavel Emelyanov
2012-08-21 13:08 ` Boaz Harrosh
2012-08-21 13:12 ` Al Viro
2012-08-21 13:40 ` Cyrill Gorcunov
2012-08-21 12:09 ` J. Bruce Fields
2012-08-21 12:25 ` Pavel Emelyanov
2012-08-22 5:49 ` Aneesh Kumar K.V
2012-08-23 8:06 ` Cyrill Gorcunov
2012-08-23 8:54 ` Marco Stornelli
2012-08-23 9:29 ` Cyrill Gorcunov
2012-08-15 9:21 ` [patch 5/8] fs, notify: Add procfs fdinfo helper v3 Cyrill Gorcunov
2012-08-15 9:21 ` [patch 6/8] fs, eventfd: Add procfs fdinfo helper Cyrill Gorcunov
2012-08-15 9:21 ` [patch 7/8] fs, epoll: Add procfs fdinfo helper v2 Cyrill Gorcunov
2012-08-15 9:21 ` [patch 8/8] fdinfo: Show sigmask for signalfd fd v2 Cyrill Gorcunov
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