Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764092AbXEUTEQ (ORCPT ); Mon, 21 May 2007 15:04:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756769AbXEUTED (ORCPT ); Mon, 21 May 2007 15:04:03 -0400 Received: from mx1.redhat.com ([66.187.233.31]:34360 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756759AbXEUTEA (ORCPT ); Mon, 21 May 2007 15:04:00 -0400 Message-ID: <4651ECD3.3060703@redhat.com> Date: Mon, 21 May 2007 14:02:43 -0500 From: Eric Sandeen User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Eric Sandeen CC: Linux Kernel Mailing List , Tejun Heo , Maneesh Soni , stable@kernel.org Subject: Re: [stable] [PATCH] - fix oops in sysfs_readdir References: <4651E0C9.3080609@redhat.com> In-Reply-To: <4651E0C9.3080609@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3548 Lines: 108 Eric Sandeen wrote: > This is a non-ida backport of Tejun's patch in -mm at: > 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 the 2.6.16 -stable tree - it follows the same scheme of using s_ino to safely > store & retrieve the inode number of sysfs entries for use in sysfs_readdir, > but uses a brain-dead-simple inode nr allocator rather than ida, which would > bring along a lot of newer, more complex code. > > No, this doesn't guarantee uniqueness of sysfs inode numbers, but then > the code in -stable today doesn't either - and with this change, at least > it shouldn't oops. > > Comments? > > Thanks, > > -Eric Here's one that works w/2.6.21... the global should probably be an atomic or lock-protected, I suppose, but again, if we don't guarantee uniqueness anyway...? Signed-off-by: Eric Sandeen Index: linux-2.6.21/fs/sysfs/dir.c =================================================================== --- linux-2.6.21.orig/fs/sysfs/dir.c +++ linux-2.6.21/fs/sysfs/dir.c @@ -32,6 +32,14 @@ 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 */ @@ -511,7 +519,7 @@ 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++; @@ -540,10 +548,7 @@ 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; - 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/