From patchwork Tue Sep 12 21:53:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Aring X-Patchwork-Id: 13382223 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 7E2CFBA28 for ; Tue, 12 Sep 2023 21:53:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694555632; 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=//nek6/ne2ovuV3WtIFZKKv22HdvaTJOJBdTaDhEBYo=; b=GORZkpcG0Qz4jRwnYUlpoU/ygRuP7axnh7fhexVt+9DWbMTzwjW4LXHWcYf6C2kmmgJ5ty f+BX7ib4+6wl/4yvf8I79G3cbpyqWgKnzlOXzSuf9W8H6jLKC+yT+myhZQi5LoAMPep+sc I8dSntA0sjWy0HH9sh9aXX/vgae9Anc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-178-nhOZnKV9MfCsXEZtQEdBIQ-1; Tue, 12 Sep 2023 17:53:48 -0400 X-MC-Unique: nhOZnKV9MfCsXEZtQEdBIQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BA3BC181A6E6; Tue, 12 Sep 2023 21:53:47 +0000 (UTC) Received: from fs-i40c-03.fs.lab.eng.bos.redhat.com (fs-i40c-03.fs.lab.eng.bos.redhat.com [10.16.224.23]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6D9C940C2009; Tue, 12 Sep 2023 21:53:47 +0000 (UTC) From: Alexander Aring To: linux-nfs@vger.kernel.org Cc: gfs2@lists.linux.dev, ocfs2-devel@lists.linux.dev, linux-fsdevel@vger.kernel.org, teigland@redhat.com, rpeterso@redhat.com, agruenba@redhat.com, trond.myklebust@hammerspace.com, anna@kernel.org, chuck.lever@oracle.com, jlayton@kernel.org, aahringo@redhat.com Subject: [PATCHv2 nfsd/master 2/7] lockd: don't call vfs_lock_file() for pending requests Date: Tue, 12 Sep 2023 17:53:19 -0400 Message-Id: <20230912215324.3310111-3-aahringo@redhat.com> In-Reply-To: <20230912215324.3310111-1-aahringo@redhat.com> References: <20230912215324.3310111-1-aahringo@redhat.com> Precedence: bulk X-Mailing-List: ocfs2-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 This patch returns nlm_lck_blocked in nlmsvc_lock() when an asynchronous lock request is pending. During testing I ran into the case with the side-effects that lockd is waiting for only one lm_grant() callback because it's already part of the nlm_blocked list. If another asynchronous for the same nlm_block is triggered two lm_grant() callbacks will occur but lockd was only waiting for one. To avoid any change of existing users this handling will only being made when export_op_support_safe_async_lock() returns true. Reviewed-by: Jeff Layton Signed-off-by: Alexander Aring --- fs/lockd/svclock.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index d500e32ebb18..c313622a9578 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -541,6 +541,22 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, goto out; } + spin_lock(&nlm_blocked_lock); + /* + * If this is a lock request for an already pending + * lock request we return nlm_lck_blocked without calling + * vfs_lock_file() again. Otherwise we have two pending + * requests on the underlaying ->lock() implementation but + * only one nlm_block to being granted by lm_grant(). + */ + if (exportfs_lock_op_is_async(inode->i_sb->s_export_op) && + !list_empty(&block->b_list)) { + spin_unlock(&nlm_blocked_lock); + ret = nlm_lck_blocked; + goto out; + } + spin_unlock(&nlm_blocked_lock); + if (!wait) lock->fl.fl_flags &= ~FL_SLEEP; mode = lock_to_openmode(&lock->fl); @@ -553,13 +569,6 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, ret = nlm_granted; goto out; case -EAGAIN: - /* - * If this is a blocking request for an - * already pending lock request then we need - * to put it back on lockd's block list - */ - if (wait) - break; ret = async_block ? nlm_lck_blocked : nlm_lck_denied; goto out; case FILE_LOCK_DEFERRED: