Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934016AbXFFTuV (ORCPT ); Wed, 6 Jun 2007 15:50:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751665AbXFFTuI (ORCPT ); Wed, 6 Jun 2007 15:50:08 -0400 Received: from ns1.suse.de ([195.135.220.2]:51595 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751189AbXFFTuH (ORCPT ); Wed, 6 Jun 2007 15:50:07 -0400 Subject: patch sysfs-store-sysfs-inode-nrs-in-s_ino-to-avoid-readdir-oopses.patch queued to -stable tree To: sandeen@sandeen.net, akpm@linux-foundation.org, gregkh@suse.de, htejun@gmail.com, linux-kernel@vger.kernel.org, maneesh@in.ibm.com, sandeen@redhat.com Cc: From: Date: Wed, 06 Jun 2007 12:49:53 -0700 In-Reply-To: <46525648.8050807@sandeen.net> Message-Id: <20070606194950.D357EE83785@imap.suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5009 Lines: 141 This is a note to let you know that we have just queued up the patch titled Subject: sysfs: store sysfs inode nrs in s_ino to avoid readdir oopses to the 2.6.21-stable tree. Its filename is sysfs-store-sysfs-inode-nrs-in-s_ino-to-avoid-readdir-oopses.patch A git repo of this tree can be found at http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary >From stable-bounces@linux.kernel.org Mon May 21 19:34:01 2007 From: Eric Sandeen Date: Mon, 21 May 2007 21:32:40 -0500 Subject: sysfs: store sysfs inode nrs in s_ino to avoid readdir oopses To: Eric Sandeen Cc: stable@kernel.org, Andrew Morton , Tejun Heo , Linux Kernel Mailing List , Maneesh Soni Message-ID: <46525648.8050807@sandeen.net> Backport of ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc1/2.6.22-rc1-mm1/broken-out/gregkh-driver-sysfs-allocate-inode-number-using-ida.patch For regular files in sysfs, sysfs_readdir wants to traverse sysfs_dirent->s_dentry->d_inode->i_ino to get to the inode number. But, the dentry can be reclaimed under memory pressure, and there is no synchronization with readdir. This patch follows Tejun's scheme of allocating and storing an inode number in the new s_ino member of a sysfs_dirent, when dirents are created, and retrieving it from there for readdir, so that the pointer chain doesn't have to be traversed. Tejun's upstream patch uses a new-ish "ida" allocator which brings along some extra complexity; this -stable patch has a brain-dead incrementing counter which does not guarantee uniqueness, but because sysfs doesn't hash inodes as iunique expects, uniqueness wasn't guaranteed today anyway. Signed-off-by: Eric Sandeen Cc: Tejun Heo Cc: Maneesh Soni Signed-off-by: Greg Kroah-Hartman --- linux-2.6.21.orig/fs/sysfs/dir.c +++ linux-2.6.21/fs/sysfs/dir.c @@ -30,6 +30,14 @@ static struct dentry_operations sysfs_de .d_iput = sysfs_d_iput, }; +static unsigned int sysfs_inode_counter; +ino_t sysfs_get_inum(void) +{ + if (unlikely(sysfs_inode_counter < 3)) + sysfs_inode_counter = 3; + return sysfs_inode_counter++; +} + /* * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent */ @@ -41,6 +49,7 @@ static struct sysfs_dirent * __sysfs_new if (!sd) return NULL; + sd->s_ino = sysfs_get_inum(); atomic_set(&sd->s_count, 1); atomic_set(&sd->s_event, 1); INIT_LIST_HEAD(&sd->s_children); @@ -509,7 +518,7 @@ static int sysfs_readdir(struct file * f switch (i) { case 0: - ino = dentry->d_inode->i_ino; + ino = parent_sd->s_ino; if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) break; filp->f_pos++; @@ -538,10 +547,7 @@ static int sysfs_readdir(struct file * f name = sysfs_get_name(next); len = strlen(name); - if (next->s_dentry) - ino = next->s_dentry->d_inode->i_ino; - else - ino = iunique(sysfs_sb, 2); + ino = next->s_ino; if (filldir(dirent, name, len, filp->f_pos, ino, dt_type(next)) < 0) Index: linux-2.6.21/fs/sysfs/inode.c =================================================================== --- linux-2.6.21.orig/fs/sysfs/inode.c +++ linux-2.6.21/fs/sysfs/inode.c @@ -140,6 +140,7 @@ struct inode * sysfs_new_inode(mode_t mo inode->i_mapping->a_ops = &sysfs_aops; inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; inode->i_op = &sysfs_inode_operations; + inode->i_ino = sd->s_ino; lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key); if (sd->s_iattr) { Index: linux-2.6.21/fs/sysfs/mount.c =================================================================== --- linux-2.6.21.orig/fs/sysfs/mount.c +++ linux-2.6.21/fs/sysfs/mount.c @@ -33,6 +33,7 @@ static struct sysfs_dirent sysfs_root = .s_element = NULL, .s_type = SYSFS_ROOT, .s_iattr = NULL, + .s_ino = 1, }; static void sysfs_clear_inode(struct inode *inode) Index: linux-2.6.21/fs/sysfs/sysfs.h =================================================================== --- linux-2.6.21.orig/fs/sysfs/sysfs.h +++ linux-2.6.21/fs/sysfs/sysfs.h @@ -5,6 +5,7 @@ struct sysfs_dirent { void * s_element; int s_type; umode_t s_mode; + ino_t s_ino; struct dentry * s_dentry; struct iattr * s_iattr; atomic_t s_event; _______________________________________________ stable mailing list stable@linux.kernel.org http://linux.kernel.org/mailman/listinfo/stable Patches currently in stable-queue which might be from sandeen@sandeen.net are queue-2.6.21/sysfs-store-sysfs-inode-nrs-in-s_ino-to-avoid-readdir-oopses.patch - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/