From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [RFC v10][PATCH 08/13] Dump open file descriptors Date: Mon, 01 Dec 2008 12:51:19 -0800 Message-ID: <1228164679.2971.91.camel@nimitz> References: <1227747884-14150-1-git-send-email-orenl@cs.columbia.edu> <1227747884-14150-9-git-send-email-orenl@cs.columbia.edu> <20081128101919.GO28946@ZenIV.linux.org.uk> <1228153645.2971.36.camel@nimitz> <493447DD.7010102@cs.columbia.edu> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <493447DD.7010102-eQaUEPhvms7ENvBUuze7eA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Oren Laadan Cc: Al Viro , Andrew Morton , Linus Torvalds , 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 , Serge Hallyn , Ingo Molnar , "H. Peter Anvin" List-Id: linux-api@vger.kernel.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 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html