Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-vc0-f176.google.com ([209.85.220.176]:45475 "EHLO mail-vc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753519AbaH2Q1y (ORCPT ); Fri, 29 Aug 2014 12:27:54 -0400 Received: by mail-vc0-f176.google.com with SMTP id ik5so2710760vcb.21 for ; Fri, 29 Aug 2014 09:27:53 -0700 (PDT) MIME-Version: 1.0 Date: Fri, 29 Aug 2014 12:27:53 -0400 Message-ID: Subject: VFS regression: commit aba809cf0944 breaks MNT_SHRINKABLE automounted partitions From: Trond Myklebust To: Alexander Viro Cc: Devel FS Linux , Linux NFS Mailing List , Tao Peng Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi Al, Our internal testing shows that commit aba809cf0944 (namespace.c: get rid of mnt_ghosts) appears to break the NFS automounter functionality. When unmounting, the user now gets a permanent -EBUSY, presumably due to a refcounting issue with the patch. The reproducer is as follows: On the server, set up an export of the form: % showmount -e 192.168.214.128 Export list for 192.168.214.128: /export * On the client: [fedora19@~]$sudo mount 192.168.214.128:/ /mnt/ [fedora19@~]$df Filesystem Size Used Avail Use% Mounted on /dev/mapper/fedora-root 38G 15G 24G 38% / devtmpfs 229M 0 229M 0% /dev tmpfs 242M 80K 242M 1% /dev/shm tmpfs 242M 1.5M 241M 1% /run tmpfs 242M 0 242M 0% /sys/fs/cgroup tmpfs 242M 4.0K 242M 1% /tmp /dev/sda1 1.5G 248M 1.3G 17% /boot 192.168.214.128:/ 28G 25G 1.1G 96% /mnt [fedora19@~]$ls /mnt/export/ [fedora19@~]$df Filesystem Size Used Avail Use% Mounted on /dev/mapper/fedora-root 38G 15G 24G 38% / devtmpfs 229M 0 229M 0% /dev tmpfs 242M 80K 242M 1% /dev/shm tmpfs 242M 1.5M 241M 1% /run tmpfs 242M 0 242M 0% /sys/fs/cgroup tmpfs 242M 4.0K 242M 1% /tmp /dev/sda1 1.5G 248M 1.3G 17% /boot 192.168.214.128:/ 28G 25G 1.1G 96% /mnt 192.168.214.128:/export 28G 25G 1.1G 96% /mnt/export [fedora19@~]$sudo umount /mnt umount.nfs4: /mnt: device is busy [fedora19@~]$df Filesystem Size Used Avail Use% Mounted on /dev/mapper/fedora-root 38G 15G 24G 38% / devtmpfs 229M 0 229M 0% /dev tmpfs 242M 80K 242M 1% /dev/shm tmpfs 242M 1.5M 241M 1% /run tmpfs 242M 0 242M 0% /sys/fs/cgroup tmpfs 242M 4.0K 242M 1% /tmp /dev/sda1 1.5G 248M 1.3G 17% /boot 192.168.214.128:/ 28G 25G 1.1G 96% /mnt Reverting commit aba809cf0944 fixes the problem for us on a 3.14.15 client kernel. (Thanks to Tao Peng for providing the above reproducer and for bisecting.) Cheers Trond -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@primarydata.com