From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trond Myklebust Subject: [PATCH] namei: results of d_is_negative() should be checked after dentry revalidation Date: Fri, 9 Oct 2015 13:44:34 -0400 Message-ID: <1444412674-3077-1-git-send-email-trond.myklebust@primarydata.com> References: <9459055931ab4f269b96bad953738778@HQMAIL102.nvidia.com> Cc: Alexander Viro , Leandro Awa , Linux NFS Mailing List , Linux FS-devel Mailing List , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Torvalds Return-path: In-Reply-To: <9459055931ab4f269b96bad953738778-wO81nVYWzR5xWE4FnwvcdlaTQe2KTcn/@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org Leandro Awa writes: After switching to version 4.1.6, our parallelized and distributed workflows now fail consistently with errors of the form: T34: ./regex.c:39:22: error: config.h: No such file or directory >>From our 'git bisect' testing, the following commit appears to be the possible cause of the behavior we've been seeing: commit 766c4cbfacd8 The issue is that revalidation may cause the dentry to be dropped in NFS if, say, the client notes that the directory timestamps have changed. Reported-by: Leandro Awa Link: https://bugzilla.kernel.org/show_bug.cgi?id=104911 Fixes: 766c4cbfacd8 ("namei: d_is_negative() should be checked...") Tested-by: Leandro Awa Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org # v4.1+ Signed-off-by: Trond Myklebust --- fs/namei.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 726d211db484..33e9495a3129 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1558,8 +1558,6 @@ static int lookup_fast(struct nameidata *nd, negative = d_is_negative(dentry); if (read_seqcount_retry(&dentry->d_seq, seq)) return -ECHILD; - if (negative) - return -ENOENT; /* * This sequence count validates that the parent had no @@ -1580,6 +1578,12 @@ static int lookup_fast(struct nameidata *nd, goto unlazy; } } + /* + * Note: do negative dentry check after revalidation in + * case that drops it. + */ + if (negative) + return -ENOENT; path->mnt = mnt; path->dentry = dentry; if (likely(__follow_mount_rcu(nd, path, inode, seqp))) -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html