From nobody Sat Nov 30 06:39:13 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E58AD1BAEF8 for ; Wed, 11 Sep 2024 19:43:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726083801; cv=none; b=lQo1a28izLy15/m8jbm7DcBh4P3YjyPks+F45Qe3K+pvjI4pB9wvJBWoJI0Sdpqzgp0v77GOUtE9pBjMzlRWYKbSbdLPRL5MrP+/0UeMoiX7e/nT8cCOH5squKcL8ywkAUcS2z9MBfTXUM3HUt5FJpF6JtcEC75QaGuMAOLrjnk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726083801; c=relaxed/simple; bh=JBs0Crisuw7Mx/HDlXn/qHrSZEkKs6TKeOaWubkYBpg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kDPwwvoIp/08tUvx4vY3PZajK/VKypvlb7yhT2QdcKvlN+ssbgLX23yC6uVprgwhVmMHQHE7QuDA+tPSWpl5vaSUDpeB1wt4HNBR0Dx63paWhQWPhLEZwIixR//fkdlNYz3h+axIkszR9hrLbEWsBn3tTE66jCzFadQ4WIpsMe4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Kejn6mRh; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Kejn6mRh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726083798; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yWxsTklmkJjx+Rd0gmMs3KD/KNm3/BpXnllaXcqeyr0=; b=Kejn6mRhC/jZdqv3ueDwArfeUB6LzkIIJMUaz71F/ZbhdqWN4sP+Xo50sJ87z8avbBRXTJ K2eu1nDudFPBQCEpygkaelewa00mKLvWfgKkR7p4g6W04qA7fTlGlTcqG25NPi7FilMLby uLCxPqK392kZDbqhtH8F3Tp70AB0yts= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-164-Z7upLKxzOmitg9rb7MQx_A-1; Wed, 11 Sep 2024 15:43:15 -0400 X-MC-Unique: Z7upLKxzOmitg9rb7MQx_A-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BD3981955F42; Wed, 11 Sep 2024 19:43:12 +0000 (UTC) Received: from bcodding.csb.redhat.com (unknown [10.22.48.7]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 93A8B1956088; Wed, 11 Sep 2024 19:43:07 +0000 (UTC) From: Benjamin Coddington To: Chuck Lever , Jeff Layton , Amir Goldstein , Neil Brown , Trond Myklebust , Anna Schumaker , Jonathan Corbet , Andreas Gruenbacher , Mark Fasheh , Joel Becker , Joseph Qi , Alexander Viro , Christian Brauner , Jan Kara , Alexander Ahring Oder Aring Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, gfs2@lists.linux.dev, ocfs2-devel@lists.linux.dev Subject: [PATCH v1 1/4] fs: Introduce FOP_ASYNC_LOCK Date: Wed, 11 Sep 2024 15:42:57 -0400 Message-ID: <3330d5a324abe2ce9c1dafe89cacdc6db41945d1.1726083391.git.bcodding@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Content-Type: text/plain; charset="utf-8" Some lock managers (NLM, kNFSD) fastidiously avoid blocking their kernel threads while servicing blocking locks. If a filesystem supports asynchronous lock requests those lock managers can use notifications to quickly inform clients they have acquired a file lock. Historically, only posix_lock_file() was capable of supporting asynchronous locks so the check for support was simply file_operations->lock(), but with recent changes in DLM, both GFS2 and OCFS2 also support asynchronous locks and have started signalling their support with EXPORT_OP_ASYNC_LOCK. We recently noticed that those changes dropped the checks for whether a filesystem simply defaults to posix_lock_file(), so async lock notifications have not been attempted for NLM and NFSv4.1+ for most filesystems. While trying to fix this it has become clear that testing both the export flag combined with testing ->lock() creates quite a layering mess. It seems appropriate to signal support with a fop_flag. Add FOP_ASYNC_LOCK so that filesystems with ->lock() can signal their capability to handle lock requests asynchronously. Add a helper for lock managers to properly test that support. Signed-off-by: Benjamin Coddington --- include/linux/filelock.h | 5 +++++ include/linux/fs.h | 2 ++ 2 files changed, 7 insertions(+) diff --git a/include/linux/filelock.h b/include/linux/filelock.h index daee999d05f3..58c1120a8253 100644 --- a/include/linux/filelock.h +++ b/include/linux/filelock.h @@ -180,6 +180,11 @@ static inline void locks_wake_up(struct file_lock *fl) wake_up(&fl->c.flc_wait); } =20 +static inline bool locks_can_async_lock(const struct file_operations *fops) +{ + return !fops->lock || fops->fop_flags & FOP_ASYNC_LOCK; +} + /* fs/locks.c */ void locks_free_lock_context(struct inode *inode); void locks_free_lock(struct file_lock *fl); diff --git a/include/linux/fs.h b/include/linux/fs.h index 6ca11e241a24..78221ae589d9 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2074,6 +2074,8 @@ struct file_operations { #define FOP_DIO_PARALLEL_WRITE ((__force fop_flags_t)(1 << 3)) /* Contains huge pages */ #define FOP_HUGE_PAGES ((__force fop_flags_t)(1 << 4)) +/* Supports asynchronous lock callbacks */ +#define FOP_ASYNC_LOCK ((__force fop_flags_t)(1 << 5)) =20 /* Wrap a directory iterator that needs exclusive inode access */ int wrap_directory_iterator(struct file *, struct dir_context *, --=20 2.44.0