From patchwork Mon Dec 13 17:24:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dai Ngo X-Patchwork-Id: 12674435 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9C4FC43219 for ; Mon, 13 Dec 2021 17:24:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241288AbhLMRYg (ORCPT ); Mon, 13 Dec 2021 12:24:36 -0500 Received: from mx0a-00069f02.pphosted.com ([205.220.165.32]:1532 "EHLO mx0a-00069f02.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236018AbhLMRYd (ORCPT ); Mon, 13 Dec 2021 12:24:33 -0500 Received: from pps.filterd (m0246617.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1BDG0dhP018126; Mon, 13 Dec 2021 17:24:29 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=8bKxMld2fSR7u8bDJG93oyV8/YH0MRQpMeV1wCMI6FI=; b=uvWFNm5icJVrDibS3ktKJ99c98JOpwKLcN3I7Bn5FcxORUTpvdX4CHWt056A66AcNVlN yWc+pATbt187AVVyME61hAcDEOL/Ce32F3nLrjAVYLW2sYl4BlrCtIFCXC9q3UzjxF2v WpSWddLHbs1KGaRFhoL1Vb+XMeDxqioeiyUJkhwyP9yJ5eiLW3rkScCHoYdFKkPKk4Cz Nw2BFQi9zmr1aBD/4IMtq4Y1SFxRrDAyJIfs5/8ArJxIjnSd0XRyWQNpvGMrEZ3mnCd4 G6CnQDAqZ10+vlwslB8CmmHsY2nUaDbR1qZwjSLfmjbefkXGceWoR+GZDfPeiYAt/out iw== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by mx0b-00069f02.pphosted.com with ESMTP id 3cx3mrs8tq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Dec 2021 17:24:29 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.1.2/8.16.1.2) with SMTP id 1BDHF2ed130602; Mon, 13 Dec 2021 17:24:28 GMT Received: from pps.reinject (localhost [127.0.0.1]) by userp3020.oracle.com with ESMTP id 3cvnendvu5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Dec 2021 17:24:28 +0000 Received: from userp3020.oracle.com (userp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 1BDHOQ0P168505; Mon, 13 Dec 2021 17:24:27 GMT Received: from aserp3020.oracle.com (ksplice-shell2.us.oracle.com [10.152.118.36]) by userp3020.oracle.com with ESMTP id 3cvnendvt7-2; Mon, 13 Dec 2021 17:24:27 +0000 From: Dai Ngo To: bfields@fieldses.org Cc: chuck.lever@oracle.com, jlayton@redhat.com, viro@zeniv.linux.org.uk, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH RFC v8 1/2] fs/lock: add new callback, lm_expire_lock, to lock_manager_operations Date: Mon, 13 Dec 2021 12:24:22 -0500 Message-Id: <20211213172423.49021-2-dai.ngo@oracle.com> X-Mailer: git-send-email 2.20.1.1226.g1595ea5.dirty In-Reply-To: <20211213172423.49021-1-dai.ngo@oracle.com> References: <20211213172423.49021-1-dai.ngo@oracle.com> MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: cW3sJbN8xsRDDaYIBI2bgaxTGz3MwDwg X-Proofpoint-GUID: cW3sJbN8xsRDDaYIBI2bgaxTGz3MwDwg Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 lock manager's private data if lock conflict can be resolved else return NULL. 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 | 40 +++++++++++++++++++++++++++++++++++++--- include/linux/fs.h | 1 + 2 files changed, 38 insertions(+), 3 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 3d6fb4ae847b..5f3ea40ce2aa 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -952,8 +952,11 @@ void posix_test_lock(struct file *filp, struct file_lock *fl) { struct file_lock *cfl; + struct file_lock *checked_cfl = NULL; struct file_lock_context *ctx; struct inode *inode = locks_inode(filp); + void *res_data; + void *(*func)(void *priv, bool testonly); ctx = smp_load_acquire(&inode->i_flctx); if (!ctx || list_empty_careful(&ctx->flc_posix)) { @@ -962,11 +965,24 @@ 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 (checked_cfl != cfl && cfl->fl_lmops && + cfl->fl_lmops->lm_expire_lock) { + res_data = cfl->fl_lmops->lm_expire_lock(cfl, true); + if (res_data) { + func = cfl->fl_lmops->lm_expire_lock; + spin_unlock(&ctx->flc_lock); + func(res_data, false); + spin_lock(&ctx->flc_lock); + checked_cfl = cfl; + goto retry; + } } + locks_copy_conflock(fl, cfl); + goto out; } fl->fl_type = F_UNLCK; out: @@ -1136,10 +1152,13 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, struct file_lock *new_fl2 = NULL; struct file_lock *left = NULL; struct file_lock *right = NULL; + struct file_lock *checked_fl = NULL; struct file_lock_context *ctx; int error; bool added = false; LIST_HEAD(dispose); + void *res_data; + void *(*func)(void *priv, bool testonly); ctx = locks_get_lock_context(inode, request->fl_type); if (!ctx) @@ -1166,9 +1185,24 @@ 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 (checked_fl != fl && fl->fl_lmops && + fl->fl_lmops->lm_expire_lock) { + res_data = fl->fl_lmops->lm_expire_lock(fl, true); + if (res_data) { + func = fl->fl_lmops->lm_expire_lock; + spin_unlock(&ctx->flc_lock); + percpu_up_read(&file_rwsem); + func(res_data, false); + percpu_down_read(&file_rwsem); + spin_lock(&ctx->flc_lock); + checked_fl = fl; + 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..8cb910c3a394 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 *); + void *(*lm_expire_lock)(void *priv, bool testonly); }; struct lock_manager {