From patchwork Mon May 10 15:55:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kurz X-Patchwork-Id: 12248617 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 611DEC433ED for ; Mon, 10 May 2021 15:56:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3393F615FF for ; Mon, 10 May 2021 15:56:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231782AbhEJP5E convert rfc822-to-8bit (ORCPT ); Mon, 10 May 2021 11:57:04 -0400 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:44836 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231336AbhEJP5C (ORCPT ); Mon, 10 May 2021 11:57:02 -0400 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-450-P45J3x4rN4eaZkSPEhBiJw-1; Mon, 10 May 2021 11:55:53 -0400 X-MC-Unique: P45J3x4rN4eaZkSPEhBiJw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 15144803620; Mon, 10 May 2021 15:55:52 +0000 (UTC) Received: from bahia.redhat.com (ovpn-112-152.ams2.redhat.com [10.36.112.152]) by smtp.corp.redhat.com (Postfix) with ESMTP id C10CA19C44; Mon, 10 May 2021 15:55:49 +0000 (UTC) From: Greg Kurz To: qemu-devel@nongnu.org Cc: Vivek Goyal , virtio-fs@redhat.com, "Michael S. Tsirkin" , kvm@vger.kernel.org, "Dr. David Alan Gilbert" , Cornelia Huck , Paolo Bonzini , Stefan Hajnoczi , Miklos Szeredi , Greg Kurz Subject: [for-6.1 v3 3/3] virtiofsd: Add support for FUSE_SYNCFS request Date: Mon, 10 May 2021 17:55:39 +0200 Message-Id: <20210510155539.998747-4-groug@kaod.org> In-Reply-To: <20210510155539.998747-1-groug@kaod.org> References: <20210510155539.998747-1-groug@kaod.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=groug@kaod.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kaod.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Honor the expected behavior of syncfs() to synchronously flush all data and metadata on linux systems. Simply loop on all known submounts and call syncfs() on them. Note that syncfs() might suffer from a time penalty if the submounts are being hammered by some unrelated workload on the host. The only solution to avoid that is to avoid shared submounts. Signed-off-by: Greg Kurz --- tools/virtiofsd/fuse_lowlevel.c | 11 ++++++++ tools/virtiofsd/fuse_lowlevel.h | 12 +++++++++ tools/virtiofsd/passthrough_ll.c | 38 +++++++++++++++++++++++++++ tools/virtiofsd/passthrough_seccomp.c | 1 + 4 files changed, 62 insertions(+) diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c index 58e32fc96369..3be95ec903c9 100644 --- a/tools/virtiofsd/fuse_lowlevel.c +++ b/tools/virtiofsd/fuse_lowlevel.c @@ -1870,6 +1870,16 @@ static void do_lseek(fuse_req_t req, fuse_ino_t nodeid, } } +static void do_syncfs(fuse_req_t req, fuse_ino_t nodeid, + struct fuse_mbuf_iter *iter) +{ + if (req->se->op.syncfs) { + req->se->op.syncfs(req); + } else { + fuse_reply_err(req, ENOSYS); + } +} + static void do_init(fuse_req_t req, fuse_ino_t nodeid, struct fuse_mbuf_iter *iter) { @@ -2267,6 +2277,7 @@ static struct { [FUSE_RENAME2] = { do_rename2, "RENAME2" }, [FUSE_COPY_FILE_RANGE] = { do_copy_file_range, "COPY_FILE_RANGE" }, [FUSE_LSEEK] = { do_lseek, "LSEEK" }, + [FUSE_SYNCFS] = { do_syncfs, "SYNCFS" }, }; #define FUSE_MAXOP (sizeof(fuse_ll_ops) / sizeof(fuse_ll_ops[0])) diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h index 3bf786b03485..890c520b195a 100644 --- a/tools/virtiofsd/fuse_lowlevel.h +++ b/tools/virtiofsd/fuse_lowlevel.h @@ -1225,6 +1225,18 @@ struct fuse_lowlevel_ops { */ void (*lseek)(fuse_req_t req, fuse_ino_t ino, off_t off, int whence, struct fuse_file_info *fi); + + /** + * Synchronize file system content + * + * If this request is answered with an error code of ENOSYS, + * this is treated as success and future calls to syncfs() will + * succeed automatically without being sent to the filesystem + * process. + * + * @param req request handle + */ + void (*syncfs)(fuse_req_t req); }; /** diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index dc940a1d048b..289900c6d274 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -3153,6 +3153,43 @@ static void lo_lseek(fuse_req_t req, fuse_ino_t ino, off_t off, int whence, } } +static void lo_syncfs(fuse_req_t req) +{ + struct lo_data *lo = lo_data(req); + GHashTableIter iter; + gpointer key, value; + int err = 0; + + pthread_mutex_lock(&lo->mutex); + + g_hash_table_iter_init(&iter, lo->mnt_inodes); + while (g_hash_table_iter_next(&iter, &key, &value)) { + struct lo_inode *inode = value; + int fd; + + fuse_log(FUSE_LOG_DEBUG, "lo_syncfs(ino=%" PRIu64 ")\n", + inode->fuse_ino); + + fd = lo_inode_open(lo, inode, O_RDONLY); + if (fd < 0) { + err = -fd; + break; + } + + if (syncfs(fd) < 0) { + err = errno; + close(fd); + break; + } + + close(fd); + } + + pthread_mutex_unlock(&lo->mutex); + + fuse_reply_err(req, err); +} + static void lo_destroy(void *userdata) { struct lo_data *lo = (struct lo_data *)userdata; @@ -3214,6 +3251,7 @@ static struct fuse_lowlevel_ops lo_oper = { .copy_file_range = lo_copy_file_range, #endif .lseek = lo_lseek, + .syncfs = lo_syncfs, .destroy = lo_destroy, }; diff --git a/tools/virtiofsd/passthrough_seccomp.c b/tools/virtiofsd/passthrough_seccomp.c index 62441cfcdb95..343188447901 100644 --- a/tools/virtiofsd/passthrough_seccomp.c +++ b/tools/virtiofsd/passthrough_seccomp.c @@ -107,6 +107,7 @@ static const int syscall_allowlist[] = { SCMP_SYS(set_robust_list), SCMP_SYS(setxattr), SCMP_SYS(symlinkat), + SCMP_SYS(syncfs), SCMP_SYS(time), /* Rarely needed, except on static builds */ SCMP_SYS(tgkill), SCMP_SYS(unlinkat),