From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miklos Szeredi Subject: Re: [PATCH] ovl: fix getcwd() failure after unsuccessful rmdir Date: Wed, 2 Mar 2016 15:17:24 +0100 Message-ID: References: <1454341012-15062-1-git-send-email-rui.y.wang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <1454341012-15062-1-git-send-email-rui.y.wang@intel.com> Sender: linux-fsdevel-owner@vger.kernel.org To: Rui Wang Cc: Konstantin Khlebnikov , Al Viro , "linux-unionfs@vger.kernel.org" , Kernel Mailing List , Linux-Fsdevel , Vivek Goyal List-Id: linux-unionfs@vger.kernel.org On Mon, Feb 1, 2016 at 4:36 PM, Rui Wang wrote: > On Sat, Jan 30, 2016 5:44 PM Konstantin Khlebnikov wrote: >> On Fri, Jan 8, 2016 at 6:09 PM, Rui Wang wrote: >> ovl_remove_upper() should do d_drop() only after it successfully >> removes the dir, otherwise a subsequent getcwd() system call will >> fail, breaking userspace programs. >> >> This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491 >> >> Signed-off-by: Rui Wang >> >> Reviewed-by: Konstantin Khlebnikov >> >> The same problem also in ovl_remove_and_whiteout() - when we remove >> non-pure dentry. It checks that directory isn't empty before, but >> I'm sure that vfs_rename which exchanges dentry and whiteout could >> fail for some reason and we'll end with unhashed dentry when nothing >> actually has been changed. > > Yes I had the same feeling. There's a "goto out_d_drop" which causes > d_drop() to be called if ovl_do_rename() fails. but I wasn't able to > find a way to reproduce this problem, so I only fixed the problem > described in bug110491. It's what I could reliably test. Thanks for the patch. Added to the queue. Miklos