From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [RFC v10][PATCH 08/13] Dump open file descriptors Date: Fri, 28 Nov 2008 10:19:19 +0000 Message-ID: <20081128101919.GO28946@ZenIV.linux.org.uk> References: <1227747884-14150-1-git-send-email-orenl@cs.columbia.edu> <1227747884-14150-9-git-send-email-orenl@cs.columbia.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1227747884-14150-9-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Oren Laadan Cc: 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 , Dave Hansen , Ingo Molnar , "H. Peter Anvin" List-Id: linux-api@vger.kernel.org On Wed, Nov 26, 2008 at 08:04:39PM -0500, Oren Laadan wrote: > +int cr_scan_fds(struct files_struct *files, int **fdtable) > +{ > + struct fdtable *fdt; > + int *fds; > + int i, n = 0; > + int tot = CR_DEFAULT_FDTABLE; > + > + fds = kmalloc(tot * sizeof(*fds), GFP_KERNEL); > + if (!fds) > + return -ENOMEM; > + > + /* > + * We assume that the target task is frozen (or that we checkpoint > + * ourselves), so we can safely proceed after krealloc() from where > + * we left off; in the worst cases restart will fail. > + */ Task may be frozen, but it may share the table with any number of other tasks... > + spin_lock(&files->file_lock); > + rcu_read_lock(); > + fdt = files_fdtable(files); > + for (i = 0; i < fdt->max_fds; i++) { > + if (!fcheck_files(files, i)) > + continue; > + if (n == tot) { > + /* > + * fcheck_files() is safe with drop/re-acquire > + * of the lock, because it tests: fd < max_fds > + */ > + spin_unlock(&files->file_lock); > + rcu_read_unlock(); > + tot *= 2; /* won't overflow: kmalloc will fail */ > + fds = krealloc(fds, tot * sizeof(*fds), GFP_KERNEL); > + if (!fds) > + return -ENOMEM; > + rcu_read_lock(); > + spin_lock(&files->file_lock); > + } > + fds[n++] = i; > + } > + rcu_read_unlock(); > + spin_unlock(&files->file_lock); > + > + *fdtable = fds; > + return n; > +} > + switch (inode->i_mode & S_IFMT) { > + case S_IFREG: > + fd_type = CR_FD_FILE; > + break; > + case S_IFDIR: > + fd_type = CR_FD_DIR; > + break; > + case S_IFLNK: > + fd_type = CR_FD_LINK; Opened symlinks? May I have whatever you'd been smoking, please? -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753369AbYK1KT4 (ORCPT ); Fri, 28 Nov 2008 05:19:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751227AbYK1KTr (ORCPT ); Fri, 28 Nov 2008 05:19:47 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:47812 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750805AbYK1KTq (ORCPT ); Fri, 28 Nov 2008 05:19:46 -0500 Date: Fri, 28 Nov 2008 10:19:19 +0000 From: Al Viro To: Oren Laadan Cc: Andrew Morton , Linus Torvalds , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, Thomas Gleixner , Serge Hallyn , Dave Hansen , Ingo Molnar , "H. Peter Anvin" Subject: Re: [RFC v10][PATCH 08/13] Dump open file descriptors Message-ID: <20081128101919.GO28946@ZenIV.linux.org.uk> References: <1227747884-14150-1-git-send-email-orenl@cs.columbia.edu> <1227747884-14150-9-git-send-email-orenl@cs.columbia.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1227747884-14150-9-git-send-email-orenl@cs.columbia.edu> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 26, 2008 at 08:04:39PM -0500, Oren Laadan wrote: > +int cr_scan_fds(struct files_struct *files, int **fdtable) > +{ > + struct fdtable *fdt; > + int *fds; > + int i, n = 0; > + int tot = CR_DEFAULT_FDTABLE; > + > + fds = kmalloc(tot * sizeof(*fds), GFP_KERNEL); > + if (!fds) > + return -ENOMEM; > + > + /* > + * We assume that the target task is frozen (or that we checkpoint > + * ourselves), so we can safely proceed after krealloc() from where > + * we left off; in the worst cases restart will fail. > + */ Task may be frozen, but it may share the table with any number of other tasks... > + spin_lock(&files->file_lock); > + rcu_read_lock(); > + fdt = files_fdtable(files); > + for (i = 0; i < fdt->max_fds; i++) { > + if (!fcheck_files(files, i)) > + continue; > + if (n == tot) { > + /* > + * fcheck_files() is safe with drop/re-acquire > + * of the lock, because it tests: fd < max_fds > + */ > + spin_unlock(&files->file_lock); > + rcu_read_unlock(); > + tot *= 2; /* won't overflow: kmalloc will fail */ > + fds = krealloc(fds, tot * sizeof(*fds), GFP_KERNEL); > + if (!fds) > + return -ENOMEM; > + rcu_read_lock(); > + spin_lock(&files->file_lock); > + } > + fds[n++] = i; > + } > + rcu_read_unlock(); > + spin_unlock(&files->file_lock); > + > + *fdtable = fds; > + return n; > +} > + switch (inode->i_mode & S_IFMT) { > + case S_IFREG: > + fd_type = CR_FD_FILE; > + break; > + case S_IFDIR: > + fd_type = CR_FD_DIR; > + break; > + case S_IFLNK: > + fd_type = CR_FD_LINK; Opened symlinks? May I have whatever you'd been smoking, please? From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 28 Nov 2008 10:19:19 +0000 From: Al Viro Subject: Re: [RFC v10][PATCH 08/13] Dump open file descriptors Message-ID: <20081128101919.GO28946@ZenIV.linux.org.uk> References: <1227747884-14150-1-git-send-email-orenl@cs.columbia.edu> <1227747884-14150-9-git-send-email-orenl@cs.columbia.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1227747884-14150-9-git-send-email-orenl@cs.columbia.edu> Sender: owner-linux-mm@kvack.org Return-Path: To: Oren Laadan Cc: Andrew Morton , Linus Torvalds , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, Thomas Gleixner , Serge Hallyn , Dave Hansen , Ingo Molnar , "H. Peter Anvin" List-ID: On Wed, Nov 26, 2008 at 08:04:39PM -0500, Oren Laadan wrote: > +int cr_scan_fds(struct files_struct *files, int **fdtable) > +{ > + struct fdtable *fdt; > + int *fds; > + int i, n = 0; > + int tot = CR_DEFAULT_FDTABLE; > + > + fds = kmalloc(tot * sizeof(*fds), GFP_KERNEL); > + if (!fds) > + return -ENOMEM; > + > + /* > + * We assume that the target task is frozen (or that we checkpoint > + * ourselves), so we can safely proceed after krealloc() from where > + * we left off; in the worst cases restart will fail. > + */ Task may be frozen, but it may share the table with any number of other tasks... > + spin_lock(&files->file_lock); > + rcu_read_lock(); > + fdt = files_fdtable(files); > + for (i = 0; i < fdt->max_fds; i++) { > + if (!fcheck_files(files, i)) > + continue; > + if (n == tot) { > + /* > + * fcheck_files() is safe with drop/re-acquire > + * of the lock, because it tests: fd < max_fds > + */ > + spin_unlock(&files->file_lock); > + rcu_read_unlock(); > + tot *= 2; /* won't overflow: kmalloc will fail */ > + fds = krealloc(fds, tot * sizeof(*fds), GFP_KERNEL); > + if (!fds) > + return -ENOMEM; > + rcu_read_lock(); > + spin_lock(&files->file_lock); > + } > + fds[n++] = i; > + } > + rcu_read_unlock(); > + spin_unlock(&files->file_lock); > + > + *fdtable = fds; > + return n; > +} > + switch (inode->i_mode & S_IFMT) { > + case S_IFREG: > + fd_type = CR_FD_FILE; > + break; > + case S_IFDIR: > + fd_type = CR_FD_DIR; > + break; > + case S_IFLNK: > + fd_type = CR_FD_LINK; Opened symlinks? May I have whatever you'd been smoking, please? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org