From patchwork Mon Oct 5 11:02:29 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 7326571 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id ECD489F1D5 for ; Mon, 5 Oct 2015 11:04:04 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 10500206EB for ; Mon, 5 Oct 2015 11:04:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0D66B206E9 for ; Mon, 5 Oct 2015 11:04:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751552AbbJELDA (ORCPT ); Mon, 5 Oct 2015 07:03:00 -0400 Received: from mail-qg0-f41.google.com ([209.85.192.41]:36175 "EHLO mail-qg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751501AbbJELC5 (ORCPT ); Mon, 5 Oct 2015 07:02:57 -0400 Received: by qgx61 with SMTP id 61so145873463qgx.3 for ; Mon, 05 Oct 2015 04:02:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=3Y9YEO2qZgAuVqt9Lu27xoqPQHD+gBPM1tkwuxZWsro=; b=gHauKM5DFJcVBoMeHsXbk/A8MvPXswJDcbzg6KedPwZ731v37cVY0sxHnpkIWFNUXo DN11v1ySgWAMQIiZYNuJNcFv3C4pwT08WrPqJ3YWb3bbvgIydaj6XsnNTzO5BrB58tYM mm7YACdk/FuXZXb/kdSZcGlV0XXxE/g3+2F0fmg+SIyZ1yf2quXzYEaPBRKvJNa9Y9Tx wp+Ve8kdXZz50c1rRICvIDKR1ZuGl/N0vDhIRNzHuGG+bGHwjkUy1X4c9mR2IR/b6Pqz BNFB1NSgkZUpd/goZmsc3eEP0gA3nC8BkM2VIN875BW/4XmFuaH0Y+znpt3SCg9cSKID N+xg== X-Gm-Message-State: ALoCoQnZVIDri8S32+KIfGlBEXmgkj0d53nEgaHNiiiRsLRK7LzpQzLAq6Vx4CNiJF5cj7PkuKey X-Received: by 10.140.233.137 with SMTP id e131mr40422392qhc.37.1444042975383; Mon, 05 Oct 2015 04:02:55 -0700 (PDT) Received: from tlielax.poochiereds.net ([2606:a000:1125:6079::d5a]) by smtp.googlemail.com with ESMTPSA id p39sm4977719qkp.47.2015.10.05.04.02.54 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Oct 2015 04:02:54 -0700 (PDT) From: Jeff Layton X-Google-Original-From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Al Viro Subject: [PATCH v5 07/20] locks: create a new notifier chain for lease attempts Date: Mon, 5 Oct 2015 07:02:29 -0400 Message-Id: <1444042962-6947-8-git-send-email-jeff.layton@primarydata.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1444042962-6947-1-git-send-email-jeff.layton@primarydata.com> References: <1444042962-6947-1-git-send-email-jeff.layton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP With the new file caching infrastructure in nfsd, we can end up holding files open for an indefinite period of time, even when they are still idle. This may prevent the kernel from handing out leases on the file, which is something we don't want to block. Fix this by running a SRCU notifier call chain whenever on any lease attempt. nfsd can then purge the cache for that inode before returning. Since SRCU is only conditionally compiled in, we must only define the new chain if it's enabled, and users of the chain must ensure that SRCU is enabled. Signed-off-by: Jeff Layton --- fs/locks.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 1 + 2 files changed, 38 insertions(+) diff --git a/fs/locks.c b/fs/locks.c index 2a54c800a223..a2d5794d713a 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -166,6 +166,7 @@ int lease_break_time = 45; DEFINE_STATIC_LGLOCK(file_lock_lglock); static DEFINE_PER_CPU(struct hlist_head, file_lock_list); + /* * The blocked_hash is used to find POSIX lock loops for deadlock detection. * It is protected by blocked_lock_lock. @@ -1780,6 +1781,40 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp, } EXPORT_SYMBOL(generic_setlease); +#if IS_ENABLED(CONFIG_SRCU) +/* + * Kernel subsystems can register to be notified on any attempt to set + * a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd + * to close files that it may have cached when there is an attempt to set a + * conflicting lease. + */ +struct srcu_notifier_head lease_notifier_chain; +EXPORT_SYMBOL_GPL(lease_notifier_chain); + +static inline void +lease_notifier_chain_init(void) +{ + srcu_init_notifier_head(&lease_notifier_chain); +} + +static inline void +setlease_notifier(long arg, struct file_lock *lease) +{ + if (arg != F_UNLCK) + srcu_notifier_call_chain(&lease_notifier_chain, arg, lease); +} +#else /* !IS_ENABLED(CONFIG_SRCU) */ +static inline void +lease_notifier_chain_init(void) +{ +} + +static inline void +setlease_notifier(long arg, struct file_lock *lease) +{ +} +#endif /* IS_ENABLED(CONFIG_SRCU) */ + /** * vfs_setlease - sets a lease on an open file * @filp: file pointer @@ -1800,6 +1835,7 @@ EXPORT_SYMBOL(generic_setlease); int vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv) { + setlease_notifier(arg, *lease); if (filp->f_op->setlease) return filp->f_op->setlease(filp, arg, lease, priv); else @@ -2696,6 +2732,7 @@ static int __init filelock_init(void) for_each_possible_cpu(i) INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i)); + lease_notifier_chain_init(); return 0; } diff --git a/include/linux/fs.h b/include/linux/fs.h index 72d8a844c692..c0df75909dd4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1042,6 +1042,7 @@ extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg); extern int fcntl_getlease(struct file *filp); /* fs/locks.c */ +extern struct srcu_notifier_head lease_notifier_chain; void locks_free_lock_context(struct file_lock_context *ctx); void locks_free_lock(struct file_lock *fl); extern void locks_init_lock(struct file_lock *);