From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45436 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbcGKXUT (ORCPT ); Mon, 11 Jul 2016 19:20:19 -0400 Subject: Patch "make nfs_atomic_open() call d_drop() on all ->open_context() errors." has been added to the 4.4-stable tree To: viro@ZenIV.linux.org.uk, Anna.Schumaker@Netapp.com, green@linuxhacker.ru, gregkh@linuxfoundation.org, trond.myklebust@primarydata.com, viro@zeniv.linux.org.uk Cc: , From: Date: Mon, 11 Jul 2016 15:47:50 -0700 Message-ID: <1468277270223160@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled make nfs_atomic_open() call d_drop() on all ->open_context() errors. to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: make-nfs_atomic_open-call-d_drop-on-all-open_context-errors.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From d20cb71dbf3487f24549ede1a8e2d67579b4632e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Jun 2016 13:14:36 -0400 Subject: make nfs_atomic_open() call d_drop() on all ->open_context() errors. From: Al Viro commit d20cb71dbf3487f24549ede1a8e2d67579b4632e upstream. In "NFSv4: Move dentry instantiation into the NFSv4-specific atomic open code" unconditional d_drop() after the ->open_context() had been removed. It had been correct for success cases (there ->open_context() itself had been doing dcache manipulations), but not for error ones. Only one of those (ENOENT) got a compensatory d_drop() added in that commit, but in fact it should've been done for all errors. As it is, the case of O_CREAT non-exclusive open on a hashed negative dentry racing with e.g. symlink creation from another client ended up with ->open_context() getting an error and proceeding to call nfs_lookup(). On a hashed dentry, which would've instantly triggered BUG_ON() in d_materialise_unique() (or, these days, its equivalent in d_splice_alias()). Tested-by: Oleg Drokin Signed-off-by: Al Viro Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker Signed-off-by: Greg Kroah-Hartman --- fs/nfs/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1531,9 +1531,9 @@ int nfs_atomic_open(struct inode *dir, s err = PTR_ERR(inode); trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); + d_drop(dentry); switch (err) { case -ENOENT: - d_drop(dentry); d_add(dentry, NULL); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); break; Patches currently in stable-queue which might be from viro@ZenIV.linux.org.uk are queue-4.4/make-nfs_atomic_open-call-d_drop-on-all-open_context-errors.patch