From: Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
To: Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
Cc: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Linus Torvalds <torvalds-3NddpPZAyC0@public.gmane.org>,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>,
Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>,
"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC v10][PATCH 08/13] Dump open file descriptors
Date: Mon, 01 Dec 2008 12:51:19 -0800 [thread overview]
Message-ID: <1228164679.2971.91.camel@nimitz> (raw)
In-Reply-To: <493447DD.7010102-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
On Mon, 2008-12-01 at 15:23 -0500, Oren Laadan wrote:
> Verifying that the size doesn't change does not ensure that the table's
> contents remained the same, so we can still end up with obsolete data.
With the realloc() scheme, we have virtually no guarantees about how the
fdtable that we read relates to the source. All that we know is that
the n'th fd was at this value at *some* time.
Using the scheme that I just suggested (and you evidently originally
used) at least guarantees that we have an atomic copy of the fdtable.
Why is this done in two steps? It first grabs a list of fd numbers
which needs to be validated, then goes back and turns those into 'struct
file's which it saves off. Is there a problem with doing that
fd->'struct file' conversion under the files->file_lock?
-- Dave
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next prev parent reply other threads:[~2008-12-01 20:51 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-27 1:04 [RFC v10][PATCH 00/13] Kernel based checkpoint/restart Oren Laadan
[not found] ` <1227747884-14150-1-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-27 1:04 ` [RFC v10][PATCH 01/13] Create syscalls: sys_checkpoint, sys_restart Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 02/13] Checkpoint/restart: initial documentation Oren Laadan
[not found] ` <1227747884-14150-3-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 10:45 ` Al Viro
[not found] ` <20081128104554.GP28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 18:15 ` Dave Hansen
2008-11-27 1:04 ` [RFC v10][PATCH 03/13] General infrastructure for checkpoint restart Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 04/13] x86 support for checkpoint/restart Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 05/13] Dump memory address space Oren Laadan
[not found] ` <1227747884-14150-6-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 10:53 ` Al Viro
[not found] ` <20081128105351.GQ28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 18:00 ` Dave Hansen
2008-12-01 20:57 ` Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 06/13] Restore " Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 07/13] Infrastructure for shared objects Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 08/13] Dump open file descriptors Oren Laadan
[not found] ` <1227747884-14150-9-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 10:19 ` Al Viro
[not found] ` <20081128101919.GO28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 17:47 ` Dave Hansen
2008-12-01 20:23 ` Oren Laadan
[not found] ` <493447DD.7010102-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-12-01 20:51 ` Dave Hansen [this message]
2008-12-01 21:02 ` Linus Torvalds
[not found] ` <alpine.LFD.2.00.0812011258390.3256-nfNrOhbfy2R17+2ddN/4kux8cNe9sq/dYPYVAmT7z5s@public.gmane.org>
2008-12-01 21:25 ` Dave Hansen
2008-12-01 21:20 ` Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 09/13] Restore open file descriprtors Oren Laadan
[not found] ` <1227747884-14150-10-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 11:27 ` Al Viro
[not found] ` <20081128112745.GR28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 19:22 ` Dave Hansen
2008-12-01 20:41 ` Oren Laadan
[not found] ` <49344C11.6090204-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-12-01 20:54 ` Dave Hansen
2008-12-01 21:00 ` Oren Laadan
[not found] ` <49345086.4-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-12-01 21:07 ` Dave Hansen
2008-12-02 1:31 ` Dave Hansen
2008-12-02 1:12 ` Dave Hansen
2008-11-27 1:04 ` [RFC v10][PATCH 10/13] External checkpoint of a task other than ourself Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 11/13] Track in-kernel when we expect checkpoint/restart to work Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 12/13] Checkpoint multiple processes Oren Laadan
2008-11-27 1:04 ` [RFC v10][PATCH 13/13] Restart " Oren Laadan
2008-12-03 23:58 ` [RFC v10][PATCH 00/13] Kernel based checkpoint/restart Serge E. Hallyn
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