From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752058AbaHTDus (ORCPT ); Tue, 19 Aug 2014 23:50:48 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:36336 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751699AbaHTDur (ORCPT ); Tue, 19 Aug 2014 23:50:47 -0400 X-Sasl-enc: QAt5Tze9qmL5T8FV4wwdlVSbcRXQhHx9gRAt8Hk0TN9T 1408506646 Message-ID: <1408506642.11028.36.camel@perseus.themaw.net> Subject: Re: [PATCH 0/5] RCU-walk support for autofs From: Ian Kent To: NeilBrown Cc: autofs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 20 Aug 2014 11:50:42 +0800 In-Reply-To: <1408506167.11028.32.camel@perseus.themaw.net> References: <20140818062844.9860.43007.stgit@notabene.brown> <1408350340.2533.3.camel@perseus.fritz.box> <1408442547.11314.9.camel@perseus.themaw.net> <20140819211654.5ec3853a@notabene.brown> <1408451815.11314.15.camel@perseus.themaw.net> <20140820131352.2aad3ca5@notabene.brown> <1408506167.11028.32.camel@perseus.themaw.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-3.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2014-08-20 at 11:42 +0800, Ian Kent wrote: > > > > From 201f75bc25906e8f64e28b37f1bb478958bf2987 Mon Sep 17 00:00:00 2001 > > From: NeilBrown > > Date: Wed, 20 Aug 2014 12:40:06 +1000 > > Subject: [PATCH] autofs4: make "autofs4_can_expire" idempotent. > > > > Have a "test" function change the value it is testing can > > be confusing, particularly as a future patch will be calling > > this function twice. > > > > So move the update for 'last_used' to avoid repeat expiry > > to the place where the final determination on what to expire is known. > > > > Signed-off-by: NeilBrown > > > > diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c > > index bee939efca2b..af09dada91bc 100644 > > --- a/fs/autofs4/expire.c > > +++ b/fs/autofs4/expire.c > > @@ -30,12 +30,6 @@ static inline int autofs4_can_expire(struct dentry *dentry, > > /* Too young to die */ > > if (!timeout || time_after(ino->last_used + timeout, now)) > > return 0; > > - > > - /* update last_used here :- > > - - obviously makes sense if it is in use now > > - - less obviously, prevents rapid-fire expire > > - attempts if expire fails the first time */ > > - ino->last_used = now; > > } > > return 1; > > } > > @@ -541,6 +535,8 @@ int autofs4_expire_run(struct super_block *sb, > > > > spin_lock(&sbi->fs_lock); > > ino = autofs4_dentry_ino(dentry); > > + /* avoid rapid-fire expire attempts if expiry fails */ > > + ino->last_used = now; > > ino->flags &= ~AUTOFS_INF_EXPIRING; > > complete_all(&ino->expire_complete); > > spin_unlock(&sbi->fs_lock); > > @@ -567,6 +563,8 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, > > ret = autofs4_wait(sbi, dentry, NFY_EXPIRE); > > > > spin_lock(&sbi->fs_lock); > > + /* avoid rapid-fire expire attempts if expiry fails */ > > + ino->last_used = now; > > ino->flags &= ~AUTOFS_INF_EXPIRING; > > complete_all(&ino->expire_complete); > > spin_unlock(&sbi->fs_lock); > On looking a little closer I've set last_used at slightly different locations. It is still does the same thing though. I'm not fussy where we actually do this, so your call. autofs - fix last_used usage From: Ian Kent Signed-off-by: Ian Kent --- fs/autofs4/expire.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index cca5d1e..d97a761 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -30,12 +30,6 @@ static inline int autofs4_can_expire(struct dentry *dentry, /* Too young to die */ if (!timeout || time_after(ino->last_used + timeout, now)) return 0; - - /* update last_used here :- - - obviously makes sense if it is in use now - - less obviously, prevents rapid-fire expire - attempts if expire fails the first time */ - ino->last_used = now; } return 1; } @@ -341,6 +335,8 @@ struct dentry *autofs4_expire_direct(struct super_block *sb, ino->flags |= AUTOFS_INF_EXPIRING; smp_mb(); ino->flags &= ~AUTOFS_INF_NO_RCU; + /* Prevent rapid fire expire events */ + ino->last_used = now; init_completion(&ino->expire_complete); spin_unlock(&sbi->fs_lock); return root; @@ -496,6 +492,8 @@ found: ino->flags |= AUTOFS_INF_EXPIRING; smp_mb(); ino->flags &= ~AUTOFS_INF_NO_RCU; + /* Prevent rapid fire expire events */ + ino->last_used = now; init_completion(&ino->expire_complete); spin_unlock(&sbi->fs_lock); spin_lock(&sbi->lookup_lock);