Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:40546 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759821Ab3JOVDV (ORCPT ); Tue, 15 Oct 2013 17:03:21 -0400 Date: Tue, 15 Oct 2013 17:03:16 -0400 To: Trond Myklebust Cc: linux-nfs@vger.kernel.org, Al Viro Subject: [PATCH] nfs: use IS_ROOT not DCACHE_DISCONNECTED Message-ID: <20131015210316.GA11616@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: From: "J. Bruce Fields" This check was added by Al Viro with d9e80b7de91db05c1c4d2e5ebbfd70b3b3ba0e0f "nfs d_revalidate() is too trigger-happy with d_drop()", with the explanation that we don't want to remove the root of a disconnected tree, which will still be included on the s_anon list. But DCACHE_DISCONNECTED does *not* actually identify dentries that are disconnected from the dentry tree or hashed on s_anon. IS_ROOT() is the way to do that. Also add a comment from Al's commit to remind us why this check is there. Signed-off-by: J. Bruce Fields --- fs/nfs/dir.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index de434f3..2acc77a 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1139,7 +1139,13 @@ out_zap_parent: if (inode && S_ISDIR(inode->i_mode)) { /* Purge readdir caches. */ nfs_zap_caches(inode); - if (dentry->d_flags & DCACHE_DISCONNECTED) + /* + * We can't d_drop the root of a disconnected tree: + * its d_hash is on the s_anon list and d_drop() would hide + * it from shrink_dcache_for_unmount(), leading to busy + * inodes on unmount and further oopses. + */ + if (IS_ROOT(dentry)) goto out_valid; } /* If we have submounts, don't unhash ! */ -- 1.7.9.5