From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DEE3C4361B for ; Tue, 15 Dec 2020 10:10:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A7D26207CC for ; Tue, 15 Dec 2020 10:09:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7D26207CC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40842 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kp7HK-00074N-9b for qemu-devel@archiver.kernel.org; Tue, 15 Dec 2020 05:09:58 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38514) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kp7G6-0006U1-3O for qemu-devel@nongnu.org; Tue, 15 Dec 2020 05:08:42 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:29505) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kp7G4-0008G5-8v for qemu-devel@nongnu.org; Tue, 15 Dec 2020 05:08:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608026919; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=w6ZPY/Z3GaAdR0pQTzOavHZvdW/IqbFGgF5UY7HhEQ8=; b=LmTq03KLdzz1K8+o+dsw8AZPeWUSzlvXkoLiLPWww2RSl5z9K1adslFj+fb5dZNAG6Y416 hZoDiRRUDQTQYFyEC/3FkNaUMpQzOBs19PzpOctDjJf17qbqd/TpU6bHJR4pH87Y/d38ri 9mxjjCRTn7j7NlX+CQ3+ims1LA9jqt4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-115-742VPhgZM1-KKWI3FrhOIA-1; Tue, 15 Dec 2020 05:08:37 -0500 X-MC-Unique: 742VPhgZM1-KKWI3FrhOIA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C55B11005513; Tue, 15 Dec 2020 10:08:35 +0000 (UTC) Received: from redhat.com (ovpn-113-23.ams2.redhat.com [10.36.113.23]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8530262690; Tue, 15 Dec 2020 10:08:33 +0000 (UTC) Date: Tue, 15 Dec 2020 10:08:30 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Li Feng Subject: Re: [PATCH v4] file-posix: detect the lock using the real file Message-ID: <20201215100830.GG121272@redhat.com> References: <1608016169-5639-1-git-send-email-fengli@smartx.com> MIME-Version: 1.0 In-Reply-To: <1608016169-5639-1-git-send-email-fengli@smartx.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , lifeng1519@gmail.com, "open list:raw" , "open list:All patches CC here" , Max Reitz , kyle@smartx.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Dec 15, 2020 at 03:09:28PM +0800, Li Feng wrote: > This patch addresses this issue: > When accessing a volume on an NFS filesystem without supporting the file lock, > tools, like qemu-img, will complain "Failed to lock byte 100". > > In the original code, the qemu_has_ofd_lock will test the lock on the > "/dev/null" pseudo-file. Actually, the file.locking is per-drive property, > which depends on the underlay filesystem. > > In this patch, add a new 'qemu_has_file_lock' to detect whether the > file supports the file lock. And disable the lock when the underlay file > system doesn't support locks. > > Signed-off-by: Li Feng > --- > v4: use the fd as the qemu_has_file_lock argument. > v3: don't call the qemu_has_ofd_lock, use a new function instead. > v2: remove the refactoring. > --- > block/file-posix.c | 66 +++++++++++++++++++++++++------------------- > include/qemu/osdep.h | 1 + > util/osdep.c | 19 +++++++++++++ > 3 files changed, 58 insertions(+), 28 deletions(-) > > diff --git a/block/file-posix.c b/block/file-posix.c > index 806764f7e3..9708212f01 100644 > --- a/block/file-posix.c > +++ b/block/file-posix.c > @@ -584,6 +584,21 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, > s->use_linux_io_uring = (aio == BLOCKDEV_AIO_OPTIONS_IO_URING); > #endif > > + s->open_flags = open_flags; > + raw_parse_flags(bdrv_flags, &s->open_flags, false); > + > + s->fd = -1; > + fd = qemu_open(filename, s->open_flags, errp); > + ret = fd < 0 ? -errno : 0; > + > + if (ret < 0) { > + if (ret == -EROFS) { > + ret = -EACCES; > + } > + goto fail; > + } > + s->fd = fd; > + > locking = qapi_enum_parse(&OnOffAuto_lookup, > qemu_opt_get(opts, "locking"), > ON_OFF_AUTO_AUTO, &local_err); > @@ -607,6 +622,13 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, > break; > case ON_OFF_AUTO_AUTO: > s->use_lock = qemu_has_ofd_lock(); > + if (s->use_lock && !qemu_has_file_lock(s->fd)) { > + /* > + * When the os supports the OFD lock, but the filesystem doesn't > + * support, just disable the file lock. > + */ > + s->use_lock = false; > + } This should just be s->use_lock = qemu_has_file_lock(s->fd) && qemu_has_ofd_lock(); > diff --git a/util/osdep.c b/util/osdep.c > index 66d01b9160..07de97e2c5 100644 > --- a/util/osdep.c > +++ b/util/osdep.c > @@ -225,6 +225,25 @@ static void qemu_probe_lock_ops(void) > } > } > > +bool qemu_has_file_lock(int fd) > +{ > +#ifdef F_OFD_SETLK > + int cmd = F_OFD_GETLK; > +#else > + int cmd = F_GETLK; > +#endif This should unconditionally use F_GETLK. > + int ret; > + struct flock fl = { > + .l_whence = SEEK_SET, > + .l_start = 0, > + .l_len = 0, > + .l_type = F_WRLCK, > + }; > + > + ret = fcntl(fd, cmd, &fl); > + return ret == 0; > +} Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|