Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752420AbZJ1SvT (ORCPT ); Wed, 28 Oct 2009 14:51:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752315AbZJ1SvQ (ORCPT ); Wed, 28 Oct 2009 14:51:16 -0400 Received: from mail-bw0-f227.google.com ([209.85.218.227]:39415 "EHLO mail-bw0-f227.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751973AbZJ1SvJ (ORCPT ); Wed, 28 Oct 2009 14:51:09 -0400 Subject: Driver-Core: devtmpfs - prevent concurrent subdirectory creation and removal From: Kay Sievers To: Greg KH Cc: linux-kernel Content-Type: text/plain; charset="UTF-8" Date: Wed, 28 Oct 2009 19:51:06 +0100 Message-Id: <1256755866.2618.321.camel@yio.site> Mime-Version: 1.0 X-Mailer: Evolution 2.28.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2416 Lines: 103 From: Kay Sievers Subject: Driver-Core: devtmpfs - prevent concurrent subdirectory creation and removal Signed-off-by: Kay Sievers --- drivers/base/devtmpfs.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -32,6 +32,8 @@ static int dev_mount = 1; static int dev_mount; #endif +static rwlock_t dirlock; + static int __init mount_param(char *str) { dev_mount = simple_strtoul(str, NULL, 0); @@ -86,16 +88,12 @@ static int dev_mkdir(const char *name, m static int create_path(const char *nodepath) { - char *path; struct nameidata nd; int err = 0; - path = kstrdup(nodepath, GFP_KERNEL); - if (!path) - return -ENOMEM; - + read_lock(&dirlock); err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt, - path, LOOKUP_PARENT, &nd); + nodepath, LOOKUP_PARENT, &nd); if (err == 0) { struct dentry *dentry; @@ -107,14 +105,17 @@ static int create_path(const char *nodep dput(dentry); } mutex_unlock(&nd.path.dentry->d_inode->i_mutex); - path_put(&nd.path); } else if (err == -ENOENT) { + char *path; char *s; /* parent directories do not exist, create them */ + path = kstrdup(nodepath, GFP_KERNEL); + if (!path) + return -ENOMEM; s = path; - while (1) { + for (;;) { s = strchr(s, '/'); if (!s) break; @@ -125,9 +126,10 @@ static int create_path(const char *nodep s[0] = '/'; s++; } + kfree(path); } + read_unlock(&dirlock); - kfree(path); return err; } @@ -232,7 +234,8 @@ static int delete_path(const char *nodep if (!path) return -ENOMEM; - while (1) { + write_lock(&dirlock); + for (;;) { char *base; base = strrchr(path, '/'); @@ -243,6 +246,7 @@ static int delete_path(const char *nodep if (err) break; } + write_unlock(&dirlock); kfree(path); return err; @@ -358,6 +362,8 @@ int __init devtmpfs_init(void) int err; struct vfsmount *mnt; + rwlock_init(&dirlock); + err = register_filesystem(&dev_fs_type); if (err) { printk(KERN_ERR "devtmpfs: unable to register devtmpfs " -- 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/