From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5B01E4E3245 for ; Wed, 30 Sep 2026 15:16:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790781424; cv=none; b=VTjyPhGKJEbvFotY6+YTjBjxpURN/1unoYsoYBqUzyH2QNTVrOXPd8vfNz58wJu0eSfwArSiDiKLcEIR7v+A2ROnIEd2FJfUTzn9ALP4IL+o6PE618id/X+P5nBb+/nAzT9ya4KYWdrlAx/L9ZHMVteISkz8+eSctke+Zj/9yro= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790781424; c=relaxed/simple; bh=5Zh63nRQsYuVa8nmALPkKoQLmfqo2zhPsXstuvG33Ts=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UT5PlX+8liFccRFxq/rIHvkid9G5B4k9JdNsrgVStkOtqYQKXQNdBTSkpCHJ9ZL4z4cPFFvQdgC/t5NQUgQx0itJyPpNDcO+GQREi5/YFaYowmldvLnH2pphYYDZmiTwv13BJ27sl4gFZ5QKtsvDXYfkv9OHldyO4mrX2IS9WdI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E6tMtOMd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E6tMtOMd" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 100DB1F00893; Wed, 30 Sep 2026 15:16:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790781415; bh=WBdxlJqLRetcvZDTBbGyTtxPDzHf//xPxmjPpHLltcs=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=E6tMtOMdC7WptKI4A0z2AyH+gPdlUzRuEIu4pPuCgBb6J9Zeqb6NdpyNn4GE7FmoI kRfexS4eREnau+e7/a74VRxBt7WlKwvpCm/ZgMseDHPOCclFo2gfxZ6kr3XfQiVNvK 5RnI1AtAqvkZZ5d8MDfs5xN1+pJIujteSpY869MQQvey3ZQeBUFzaryZPEk/mYss3S 8NQcjy4yx8TBiCaKHHDkXL2fZhm3ksJPTRR//CL+luSFuX6hcobz9MBefBn+CO4aQN nYEakPII92txTcA819nljmsa8t/5xxnsPDExkMrKdztD+K1fGcLdzZ2+DD88YVbQGX jd+W0DaIB0sAw== Date: Wed, 30 Sep 2026 08:16:54 -0700 From: "Darrick J. Wong" To: bernd@bsbernd.com Cc: neal@gompa.dev, fuse-devel@lists.linux.dev Subject: Re: [PATCH 2/4] mount_service: mount via the shared fsmount helper Message-ID: <20260930151654.GO6253@frogsfrogsfrogs> References: <20260930-mount-service-use-mount-fsmount-v1-0-d585598896ee@bsbernd.com> <20260930-mount-service-use-mount-fsmount-v1-2-d585598896ee@bsbernd.com> Precedence: bulk X-Mailing-List: fuse-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260930-mount-service-use-mount-fsmount-v1-2-d585598896ee@bsbernd.com> On Wed, Sep 30, 2026 at 03:44:34PM +0200, Bernd Schubert via B4 Relay wrote: > From: Bernd Schubert > > util/mount_service.c issued FSCONFIG_CMD_CREATE, fsmount() and > move_mount() itself, with the same FSMOUNT_CLOEXEC and > MOVE_MOUNT_*_EMPTY_PATH flags as lib/mount_fsmount.c. Both mount the > same filesystem, so a flag changed in one copy silently diverges. > > mount_service.c also called the libc names fsconfig(), fsmount() and > move_mount() directly. HAVE_NEW_MOUNT_API only checks that the headers > declare these functions, not that libc exports them. On a system where > NEED_NEW_MOUNT_API_SYSCALL_WRAPPERS is also set (glibc older than > 2.36), lib/mount_fsmount.c works around the missing symbols through > its fuse_-prefixed static inline wrappers, which mount_service.c had > no access to; calling the bare libc names left it with a declaration > to compile against but no symbol to link against. > > Signed-off-by: Bernd Schubert > --- > util/mount_service.c | 49 ++++++++++++------------------------------------- > 1 file changed, 12 insertions(+), 37 deletions(-) > > diff --git a/util/mount_service.c b/util/mount_service.c > index 0b3266309a8a..dcdc26df1db4 100644 > --- a/util/mount_service.c > +++ b/util/mount_service.c > @@ -28,11 +28,6 @@ > #include > #include > > -#ifdef HAVE_NEW_MOUNT_API > -#include > -#include > -#endif > - > #include "mount_util.h" > #include "util.h" > #include "fuse_i.h" > @@ -1439,63 +1434,45 @@ static int mount_service_fsopen_mount(struct mount_service *mo, > return FUSE_MOUNT_FALLBACK_NEEDED; > > error = -ret; > - goto fail_fsconfig; > + goto fail_mount; > } > > snprintf(tmp, sizeof(tmp), "%i", mo->fusedevfd); > ret = apply_fsconfig_opt_fd(mo->fsopenfd, tmp); > if (ret < 0) { > error = -ret; > - goto fail_fsconfig; > + goto fail_mount; > } > > snprintf(tmp, sizeof(tmp), "%o", stbuf->st_mode & S_IFMT); > ret = apply_fsconfig_opt_string(mo->fsopenfd, "rootmode", tmp); > if (ret < 0) { > error = -ret; > - goto fail_fsconfig; > + goto fail_mount; > } > > snprintf(tmp, sizeof(tmp), "%u", getuid()); > ret = apply_fsconfig_opt_string(mo->fsopenfd, "user_id", tmp); > if (ret < 0) { > error = -ret; > - goto fail_fsconfig; > + goto fail_mount; > } > > snprintf(tmp, sizeof(tmp), "%u", getgid()); > ret = apply_fsconfig_opt_string(mo->fsopenfd, "group_id", tmp); > if (ret < 0) { > error = -ret; > - goto fail_fsconfig; > - } > - > - ret = fsconfig(mo->fsopenfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0); > - if (ret) { > - error = errno; > - fprintf(stderr, "%s: creating filesystem: %s\n", > - mo->msgtag, strerror(error)); > - goto fail_fsconfig; > - } > - > - mfd = fsmount(mo->fsopenfd, FSMOUNT_CLOEXEC, attr_flags); > - if (mfd < 0) { > - error = errno; > - fprintf(stderr, "%s: fsmount: %s\n", > - mo->msgtag, strerror(error)); > - goto fail_fsconfig; > - } > - > - ret = move_mount(mfd, "", mo->mountfd, "", > - MOVE_MOUNT_F_EMPTY_PATH | MOVE_MOUNT_T_EMPTY_PATH); > - close(mfd); > - if (ret) { > - error = errno; > - fprintf(stderr, "%s: move_mount: %s\n", > - mo->msgtag, strerror(error)); > goto fail_mount; > } > > + ret = fuse_fsmount_create_and_move(mo->fsopenfd, attr_flags, > + mo->mountfd, NULL, &mfd); > + if (ret < 0) { > + error = -ret; > + goto fail_mount; > + } > + close(mfd); Slick :) Reviewed-by: "Darrick J. Wong" --D > + > /* > * The mount succeeded, so we send a positive reply even if the mtab > * update fails. > @@ -1515,8 +1492,6 @@ static int mount_service_fsopen_mount(struct mount_service *mo, > mo->mounted = true; > return mount_service_send_reply(mo, 0); > > -fail_fsconfig: > - log_fsconfig_kmsg(mo->fsopenfd); > fail_mount: > return mount_service_send_reply(mo, error); > } > > -- > 2.53.0 > > >