From nobody Sun Nov 24 08:50:05 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 57AA020ADD2; Wed, 6 Nov 2024 19:53:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730922791; cv=none; b=lU+ltyQUetr6Reju2IwFuEMK9funCwvR0S1ECEwm+qteVlz08sJFDXdkFuexLpaGwD5ieDeGIFQL2xrevq8QgGX2Es1HIx1MN8WLBsBCR96NwlGrNiJHDVS4Q+yNuB00aXrAB39cicXLKC4llgNaPPoytpdLz5UNna1OWXaHtO8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730922791; c=relaxed/simple; bh=DhBrdZZrF/qNnTsGkr+kWchoEMI385XmDrH+TXCiMTU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=UYpQSJAXEywV+xE1e2WAbva6wfDoc5ue34nG1jIpam+8X5n12L4JWC96OSuwev1ZQ779f5PtHAF4T9dS2LbWlVyh0H3hzXzwlzVks6z7bRm5OoXZX/dC37doYATaCLYprePiz8u2nv7RAbwyZwYoU2bu2nM+dg6AuZwvDoSwdRc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eLKcqf8s; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eLKcqf8s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C732C4CED8; Wed, 6 Nov 2024 19:53:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730922790; bh=DhBrdZZrF/qNnTsGkr+kWchoEMI385XmDrH+TXCiMTU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=eLKcqf8sLB86bsnDq++J5aKyZP63ZAOxsP9Pq9uNXa+Yuv4jbwdNCMaG4JYgj+f/8 5hAl/QmGBW7o+5HRQNdgXInCK0LoZbZGhwoeVBdm4qFNM7uRafP5dffq2eBPkqByfI 82glJvG1CKf2XDcZGrr+d+bFJfC+nqlkN5bC8R8FL/q86Psq2Jco8H1K6xyJS68lJm QrzujXz3UYjRUUrZorW9MjEjubdKCT+IpjPa7FcYPH6LEtkIFfusth6hpWqlb+xWLe wOA4GBBeVMCTGqrpkBLKzf/Gnm2AHDg/ymramqojo3l794HL5HVyvubXoTrxsGTjto kQC5fG97nimtw== From: Jeff Layton Date: Wed, 06 Nov 2024 14:53:06 -0500 Subject: [PATCH v2 2/2] fs: add the ability for statmount() to report the mount devicename Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241106-statmount-v2-2-93ba2aad38d1@kernel.org> References: <20241106-statmount-v2-0-93ba2aad38d1@kernel.org> In-Reply-To: <20241106-statmount-v2-0-93ba2aad38d1@kernel.org> To: Alexander Viro , Christian Brauner , Jan Kara Cc: Josef Bacik , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Jeff Layton X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3602; i=jlayton@kernel.org; h=from:subject:message-id; bh=DhBrdZZrF/qNnTsGkr+kWchoEMI385XmDrH+TXCiMTU=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBnK8kkpOcoW5ovJOr+8opJM4in1IzvKCz4331Bt 463Gx728Q+JAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZyvJJAAKCRAADmhBGVaC FaPFEACfTeLSCABqw8VZmrzROAb1NTEgn1516lbHHa3uwOkIW1QYWPotSECmfgyN5jeKDbNjjAS eMxlPXGpa0udCTfeMNpZCMt411TEBxmrMBHo03jQqU3IldSCaHa5tBwRETiEeonBrogOOyhqei/ vssYReM6nlFkYPU/7Dj6Rj2b0z2qSKhr8aeJWDjq6eaUdWZRVfPXf5yZclc5SJ0d2BpVbdaq6ES 3jBv66a+0rpEiVg3uCE272rpVWzgtTrH0nYfegm6suSAmBEkjMcnH8y3AyCGuhdbAYTNmb2E9I8 lfWF0DDdtgeA8/98JVE1p6DOi8qL/pf9Go4YeUpWoAFojXdt2I4AGCGObmOFEpB8DN567L6aTvF Y9bU8xH2Ry3McF0ZtWjSe+5LC4sL1QNkwPOpk6hd0iOb6auw5S5P7CXmAEOyKhxrUJVTsvCr7dk cngD9qwYPdFceOFXvKiXWBzOGI29zGxtr6EsIjam4SABQJGHkU0B75eiR6Rf8HMCSRVyxeoJCjh 7oc4Is2VvxU3ZfzcOMaXjoHOUcDUAmnbhLdTV79WoGy4RKykHdLBNN+Zm1HSFsaWMIxyVv5fwIu n/RymKvp28qcCR+a57OI8kjJ1uHfYTlCRExf1wMq7j4awNB+Uarx0Jlb4PeDH3Ubpv1RdBw4YPI VaPJFHGhOyouGHQ== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 /proc/self/mountinfo displays the devicename for the mount, but statmount() doesn't yet have a way to return it. Add a new STATMOUNT_MNT_DEVNAME flag, claim the 32-bit __spare1 field to hold the offset into the str[] array. STATMOUNT_MNT_DEVNAME will only be set in the return mask if there is a device string. Signed-off-by: Jeff Layton --- fs/namespace.c | 25 ++++++++++++++++++++++++- include/uapi/linux/mount.h | 3 ++- 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 52ab892088f08ad71647eff533dd6f3025bbae03..d4ed2cb5de12c86b4da58626441= e072fc109b2ff 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -5014,6 +5014,19 @@ static void statmount_fs_subtype(struct kstatmount *= s, struct seq_file *seq) seq_puts(seq, sb->s_subtype); } =20 +static int statmount_mnt_devname(struct kstatmount *s, struct seq_file *se= q) +{ + struct super_block *sb =3D s->mnt->mnt_sb; + struct mount *r =3D real_mount(s->mnt); + + if (sb->s_op->show_devname) + return sb->s_op->show_devname(seq, s->mnt->mnt_root); + + if (r->mnt_devname) + seq_puts(seq, r->mnt_devname); + return 0; +} + static void statmount_mnt_ns_id(struct kstatmount *s, struct mnt_namespace= *ns) { s->sm.mask |=3D STATMOUNT_MNT_NS_ID; @@ -5078,6 +5091,12 @@ static int statmount_string(struct kstatmount *s, u6= 4 flag) if (seq->count =3D=3D sm->fs_subtype) return 0; break; + case STATMOUNT_MNT_DEVNAME: + sm->mnt_devname =3D seq->count; + ret =3D statmount_mnt_devname(s, seq); + if (seq->count =3D=3D sm->mnt_devname) + return ret; + break; default: WARN_ON_ONCE(true); return -EINVAL; @@ -5220,6 +5239,9 @@ static int do_statmount(struct kstatmount *s, u64 mnt= _id, u64 mnt_ns_id, if (!err && s->mask & STATMOUNT_FS_SUBTYPE) err =3D statmount_string(s, STATMOUNT_FS_SUBTYPE); =20 + if (!err && s->mask & STATMOUNT_MNT_DEVNAME) + err =3D statmount_string(s, STATMOUNT_MNT_DEVNAME); + if (!err && s->mask & STATMOUNT_MNT_NS_ID) statmount_mnt_ns_id(s, ns); =20 @@ -5241,7 +5263,8 @@ static inline bool retry_statmount(const long ret, si= ze_t *seq_size) } =20 #define STATMOUNT_STRING_REQ (STATMOUNT_MNT_ROOT | STATMOUNT_MNT_POINT | \ - STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS | STATMOUNT_FS_SUBTYPE) + STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS | \ + STATMOUNT_FS_SUBTYPE | STATMOUNT_MNT_DEVNAME) =20 static int prepare_kstatmount(struct kstatmount *ks, struct mnt_id_req *kr= eq, struct statmount __user *buf, size_t bufsize, diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h index fa206fb56b3b25cf80f7d430e1b6bab19c3220e4..0f9ea2748f6376b5e71ba969598= fc5b641a2c77f 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -174,7 +174,7 @@ struct statmount { __u32 mnt_point; /* [str] Mountpoint relative to current root */ __u64 mnt_ns_id; /* ID of the mount namespace */ __u32 fs_subtype; /* [str] Subtype of fs_type (if any) */ - __u32 __spare1[1]; + __u32 mnt_devname; /* [str] Device string for the mount */ __u64 __spare2[48]; char str[]; /* Variable size part containing strings */ }; @@ -210,6 +210,7 @@ struct mnt_id_req { #define STATMOUNT_MNT_NS_ID 0x00000040U /* Want/got mnt_ns_id */ #define STATMOUNT_MNT_OPTS 0x00000080U /* Want/got mnt_opts */ #define STATMOUNT_FS_SUBTYPE 0x00000100U /* Want/got subtype */ +#define STATMOUNT_MNT_DEVNAME 0x00000200U /* Want/got devname */ =20 /* * Special @mnt_id values that can be passed to listmount --=20 2.47.0