From patchwork Fri Sep 24 20:52:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dai Ngo X-Patchwork-Id: 12516787 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A939DC433F5 for ; Fri, 24 Sep 2021 20:53:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9342D60F13 for ; Fri, 24 Sep 2021 20:53:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345776AbhIXUzE (ORCPT ); Fri, 24 Sep 2021 16:55:04 -0400 Received: from mx0a-00069f02.pphosted.com ([205.220.165.32]:15176 "EHLO mx0a-00069f02.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345737AbhIXUzD (ORCPT ); Fri, 24 Sep 2021 16:55:03 -0400 Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 18OKYBP5030096; Fri, 24 Sep 2021 20:53:29 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2021-07-09; bh=gUUL68PzT1tsHqbh2Eu96RtT1DlD2y4rsvPdvYDuQH0=; b=Ub668+HbGM4rcBPKH/buW6bfd5q4jLM5e6t8Lwyi9nPtQAsoVn4D21+spGbZqOx5+Bym eaZ3DR89M5WLA9bTMm8lNAyANy3kEtR7IuJpVuGteQIg7mqiP2JIfcDWE9IivdsCh+xV hpInXV7vgkZzxksnRPE0kjt2qCyu6NBjtxEaU1iONehqFSEj5KHXbCkuKszIntIh376N B5HgXNBuP9EodVjqt3y7k4r7xZgJXBgDYLZC5tRRJFH2/P4mYYzOJ+JngMqO9Wzc/Gn0 2kbzN7S2bG5xggWDRFPzj0vJOETryz0GcKqjogAOro4c8jrEzJgJKuDucH/3K8nUeYs2 +A== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by mx0b-00069f02.pphosted.com with ESMTP id 3b93eq5q67-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Sep 2021 20:53:26 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 18OKoxvT158474; Fri, 24 Sep 2021 20:53:24 GMT Received: from pps.reinject (localhost [127.0.0.1]) by aserp3020.oracle.com with ESMTP id 3b93fr897p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Sep 2021 20:53:24 +0000 Received: from aserp3020.oracle.com (aserp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 18OKrNkT167020; Fri, 24 Sep 2021 20:53:24 GMT Received: from userp3020.oracle.com (ksplice-shell2.us.oracle.com [10.152.118.36]) by aserp3020.oracle.com with ESMTP id 3b93fr8971-2; Fri, 24 Sep 2021 20:53:24 +0000 From: Dai Ngo To: bfields@fieldses.org Cc: chuck.lever@oracle.com, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH RFC v4 1/2] fs/lock: add new callback, lm_expire_lock, to lock_manager_operations Date: Fri, 24 Sep 2021 16:52:51 -0400 Message-Id: <20210924205252.82502-2-dai.ngo@oracle.com> X-Mailer: git-send-email 2.20.1.1226.g1595ea5.dirty In-Reply-To: <20210924205252.82502-1-dai.ngo@oracle.com> References: <20210924205252.82502-1-dai.ngo@oracle.com> MIME-Version: 1.0 X-Proofpoint-GUID: A8CNH7TmnHnrv7t5jzM-_V6nndwjO3Dc X-Proofpoint-ORIG-GUID: A8CNH7TmnHnrv7t5jzM-_V6nndwjO3Dc Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Add new callback, lm_expire_lock, to lock_manager_operations to allow the lock manager to take appropriate action to resolve the lock conflict if possible. The callback takes 2 arguments, file_lock of the blocker and a testonly flag: testonly = 1 check and return true if lock conflict can be resolved else return false. testonly = 0 resolve the conflict if possible, return true if conflict was resolved esle return false. Lock manager, such as NFSv4 courteous server, uses this callback to resolve conflict by destroying lock owner, or the NFSv4 courtesy client (client that has expired but allowed to maintains its states) that owns the lock. Signed-off-by: Dai Ngo --- fs/locks.c | 26 +++++++++++++++++++++++--- include/linux/fs.h | 1 + 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 3d6fb4ae847b..893b348a2d57 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -954,6 +954,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl) struct file_lock *cfl; struct file_lock_context *ctx; struct inode *inode = locks_inode(filp); + bool ret; ctx = smp_load_acquire(&inode->i_flctx); if (!ctx || list_empty_careful(&ctx->flc_posix)) { @@ -962,11 +963,20 @@ posix_test_lock(struct file *filp, struct file_lock *fl) } spin_lock(&ctx->flc_lock); +retry: list_for_each_entry(cfl, &ctx->flc_posix, fl_list) { - if (posix_locks_conflict(fl, cfl)) { - locks_copy_conflock(fl, cfl); - goto out; + if (!posix_locks_conflict(fl, cfl)) + continue; + if (cfl->fl_lmops && cfl->fl_lmops->lm_expire_lock && + cfl->fl_lmops->lm_expire_lock(cfl, 1)) { + spin_unlock(&ctx->flc_lock); + ret = cfl->fl_lmops->lm_expire_lock(cfl, 0); + spin_lock(&ctx->flc_lock); + if (ret) + goto retry; } + locks_copy_conflock(fl, cfl); + goto out; } fl->fl_type = F_UNLCK; out: @@ -1140,6 +1150,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, int error; bool added = false; LIST_HEAD(dispose); + bool ret; ctx = locks_get_lock_context(inode, request->fl_type); if (!ctx) @@ -1166,9 +1177,18 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, * blocker's list of waiters and the global blocked_hash. */ if (request->fl_type != F_UNLCK) { +retry: list_for_each_entry(fl, &ctx->flc_posix, fl_list) { if (!posix_locks_conflict(request, fl)) continue; + if (fl->fl_lmops && fl->fl_lmops->lm_expire_lock && + fl->fl_lmops->lm_expire_lock(fl, 1)) { + spin_unlock(&ctx->flc_lock); + ret = fl->fl_lmops->lm_expire_lock(fl, 0); + spin_lock(&ctx->flc_lock); + if (ret) + goto retry; + } if (conflock) locks_copy_conflock(conflock, fl); error = -EAGAIN; diff --git a/include/linux/fs.h b/include/linux/fs.h index e7a633353fd2..1a76b6451398 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1071,6 +1071,7 @@ struct lock_manager_operations { int (*lm_change)(struct file_lock *, int, struct list_head *); void (*lm_setup)(struct file_lock *, void **); bool (*lm_breaker_owns_lease)(struct file_lock *); + bool (*lm_expire_lock)(struct file_lock *fl, bool testonly); }; struct lock_manager {