Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754950Ab0BXAMY (ORCPT ); Tue, 23 Feb 2010 19:12:24 -0500 Received: from adelie.canonical.com ([91.189.90.139]:42570 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754833Ab0BXAMV (ORCPT ); Tue, 23 Feb 2010 19:12:21 -0500 From: john.johansen@canonical.com To: linux-kernel@vger.kernel.org Cc: linux-fsdevel-owner@vger.kernel.org, John Johansen Subject: [PATCH] Fix __d_path for lazy unmounts Date: Tue, 23 Feb 2010 16:12:09 -0800 Message-Id: <1266970329-28068-2-git-send-email-john.johansen@canonical.com> X-Mailer: git-send-email 1.6.6.1 In-Reply-To: <20100223010413.GA31046@us.ibm.com> References: <20100223010413.GA31046@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2436 Lines: 71 From: John Johansen When __d_path() hits a lazily unmounted mount point, it tries to prepend the name of the lazily unmounted dentry to the path name. It gets this wrong, and also overwrites the slash that separates the name from the following pathname component. This patch fixes that; if a process was in directory /foo/bar and /foo got lazily unmounted, the old result was ``foobar'' (note the missing slash), while the new result with this patch is ``/foo/bar''. Signed-off-by: John Johansen --- fs/dcache.c | 27 +++++++++++++++++++++++---- 1 files changed, 23 insertions(+), 4 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 953173a..46096b4 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1922,11 +1922,9 @@ char *__d_path(const struct path *path, struct path *root, retval = end-1; *retval = '/'; - for (;;) { + while (dentry != root->dentry || vfsmnt != root->mnt) { struct dentry * parent; - if (dentry == root->dentry && vfsmnt == root->mnt) - break; if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { /* Global root? */ if (vfsmnt->mnt_parent == vfsmnt) { @@ -1950,9 +1948,30 @@ out: return retval; global_root: - retval += 1; /* hit the slash */ + /* + * We went past the (vfsmount, dentry) we were looking for and have + * either hit a root dentry, a lazily unmounted dentry, an + * unconnected dentry, or the file is on a pseudo filesystem. + */ + if ((dentry->d_sb->s_flags & MS_NOUSER) || + (dentry->d_name.len == 1 && *dentry->d_name.name == '/')) { + /* + * Historically, we also glue together the root dentry and + * remaining name for pseudo filesystems like pipefs, which + * have the MS_NOUSER flag set. This results in pathnames + * like "pipe:[439336]". + */ + retval += 1; /* overwrite the slash */ + buflen++; + } if (prepend_name(&retval, &buflen, &dentry->d_name) != 0) goto Elong; + + /* connect lazily unmounted mount point */ + if (*retval != '/' && !(dentry->d_sb->s_flags & MS_NOUSER) && + prepend(&retval, &buflen, "/", 1) != 0) + goto Elong; + root->mnt = vfsmnt; root->dentry = dentry; goto out; -- 1.6.6.1 -- 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/