From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: VFS: Busy inodes after unmount on 2 way SMP Date: Thu, 11 Sep 2003 18:05:44 -0700 Sender: autofs-bounces@linux.kernel.org Message-ID: <3F611BE8.6040900@zytor.com> References: <3F610F3C.5040704@intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3F610F3C.5040704@intel.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: autofs-bounces@linux.kernel.org Content-Type: text/plain; charset="us-ascii" To: Arun Sharma Cc: autofs@linux.kernel.org, nfs@lists.sourceforge.net Arun Sharma wrote: > > We've seen a few "VFS: Busy inodes after unmount. Self-destruct in 5 > seconds. Have a nice day.." messages on a dual processor NFS client. > Here's the use case: > > - Due to network load issues, the NFS server becomes unreachable for > some time > - The automounter tries to expire the mount > - The unmount finds a couple of busy inodes. Putting some debug printks > shows that typically two inodes are busy i.e. have inode->i_count == 1. > But they don't have any waiters on inode->i_wait. Further, the inodes > that are busy are > /mnt/foo -> autofs mount point > /mnt/foo/bar -> bar is a symbolic link > > It's not clear if this is a NFS issue or a autofs issue, but it's seen > often with autofs. Are there any known race conditions that have been > fixed after 2.4.20 ? The two calls I'm worried about are: > > fs/autofs/root.c:305: d_instantiate(dentry, iget(dir->i_sb,ent->ino)); > fs/autofs/root.c:416: d_instantiate(dentry, iget(dir->i_sb,ino)); > Which version of autofs are you running? What version of mount(8)? It's possible NFS lets you umount a mount which has busy inodes under certain conditions. autofs stresses mounting/umounting NFS in ways that sometimes exposes bugs that otherwise wouldn't be seen. -hpa