From nobody Sun Nov 24 09:09:26 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 3C211206E92; Wed, 6 Nov 2024 19:53:10 +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=1730922790; cv=none; b=lBHii0g1YZuo3bk+UMXCjndS5DtIUdfrJxB6cFQf2ePHpa4gDITwZ5KnPJW6ROvZ8yGLmIfMl0FFTh+gr9gsQaTYMOVxA3vGQMm+djxt2fG5KwW+JyAAQiDD4aABFlV44dueO6EhfvM92YiIj0oPL1RgS8Eq9hOzVzk7i0FavPg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730922790; c=relaxed/simple; bh=S99XA7AgZ9d2AueEW12kJQDhWH2cMia53cdtSAxsIQU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=GLSkp+j/1z7Hdej3WR7Ln+Kn+YnM/YGMT7QiMgLZW8pWfDdSD3hYgc9AJVZXPdlEsitz+xyVyJ2PGFyEx5MirJCWAWm7YRUMMFCjEih7UNCwpLXS5+cX6NEsYVmphWcMjj6XuG71Vc3Ir4SPkVleQZOkAPcMrV4YNv0ikTmUSb4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Da0uugc4; 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="Da0uugc4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7539CC4CED0; Wed, 6 Nov 2024 19:53:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730922790; bh=S99XA7AgZ9d2AueEW12kJQDhWH2cMia53cdtSAxsIQU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Da0uugc4+beHteMZxgVBv4QoLbWO8a/jPUmA0joB+KMm+rbQndmPNR7sEPKynuff7 A2p4jOULwO/D+kZZoStk1541RpBxIE4mx5CPMGAd0+e+ujV/bnRpEymRQLE5WZVYso 9Qc+GvfVNNwMQUdX9EsEj526EZdld/t4j0b9qH4mpNt1hDajAvCAnkJPHx/yKcx2fF fiS1TN1SA0z2Po2uCebkOXxni5sT5pgc5G191bAInYw5QdtPUFX48HztR4t5/0vej2 Qo13OepzmNMOUPQVWIXyM1zPO1ne9aYrZv1VxtFJhKMstzrC3hbV4y/nXkWm7efOhb 6k/J+mI+okRBg== From: Jeff Layton Date: Wed, 06 Nov 2024 14:53:05 -0500 Subject: [PATCH v2 1/2] fs: add the ability for statmount() to report the fs_subtype 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-v2-1-93ba2aad38d1@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=3515; i=jlayton@kernel.org; h=from:subject:message-id; bh=S99XA7AgZ9d2AueEW12kJQDhWH2cMia53cdtSAxsIQU=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBnK8kkR/jaPoQoF4sQRd/s38if4a9yYG/xTAr05 ACb6zytjquJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZyvJJAAKCRAADmhBGVaC FdBgD/4h/83rA3CxDQ05ageJCFggZk8COaeND3HPgINacUYCXfGC21GnNs+i7aN8Q3ml+8mPoqz 34rWrWunTAIQm4X42at5Gpsd6JxAj7Xue54gOV6AbqlR5MeOtbfc09vt6FO68tYkONcu0SgU6pA gsMwItwPsyxpFIA9WjvfxjG4K4vCFjcf/8qItbTfPSTiWTIUwsESQnjUALSO1rXRQFsRSwYKAxP 38jDsiG+Tk7UhMnucyJybjUprEa/6ohcaQJ9rvSIuhcVYLH7Q/OAtrjTdoCcHzhz3jVvvQh4cJC dhYJbYRomU3QpxU3VfunUOEzMblqo2VOcca6M30QOYRfeHqiMSgd6d5hFXHU6/Be4xIKXYunv+E ZDUTnArnkXSfbWMPiZqO5f1ViqR3bFH48dykWEgSn9lW2Wlo80hfxJw9BCfV88s2GAgsq48sv5+ r2+E9H9JoIDW55mR4xz0WqKibpuxtTukdZxiV5aEeOFx8gdP9mYsnefKBcgjHWVTxa53YudRGMu EOnMbcUpxFK1RtQJg6/UC2YrugpJQbXagJrzVTwQ/oXLyFqbOetc3gsLGQJtpMTbREu0fFnSyTV GA4RrOEtw8ZLmiUxeAH5n0uYUTPHtqChgPdYbNuuef2PY11ffXTqzzzZa5C4YICDWB68coEYyRw 57Bac3v6wH2QJyg== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 /proc/self/mountinfo prints out the sb->s_subtype after the type. This is particularly useful for disambiguating FUSE mounts (at least when the userland driver bothers to set it). Add STATMOUNT_FS_SUBTYPE and claim one of the __spare2 fields to point to the offset into the str[] array. STATMOUNT_FS_SUBTYPE will only be set in the return mask if there is a subtype associated with the mount. Reviewed-by: Jan Kara Signed-off-by: Jeff Layton --- fs/namespace.c | 19 ++++++++++++++++++- include/uapi/linux/mount.h | 5 ++++- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index ba77ce1c6788dfe461814b5826fcbb3aab68fad4..52ab892088f08ad71647eff533d= d6f3025bbae03 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -5006,6 +5006,14 @@ static int statmount_fs_type(struct kstatmount *s, s= truct seq_file *seq) return 0; } =20 +static void statmount_fs_subtype(struct kstatmount *s, struct seq_file *se= q) +{ + struct super_block *sb =3D s->mnt->mnt_sb; + + if (sb->s_subtype) + seq_puts(seq, sb->s_subtype); +} + static void statmount_mnt_ns_id(struct kstatmount *s, struct mnt_namespace= *ns) { s->sm.mask |=3D STATMOUNT_MNT_NS_ID; @@ -5064,6 +5072,12 @@ static int statmount_string(struct kstatmount *s, u6= 4 flag) sm->mnt_opts =3D seq->count; ret =3D statmount_mnt_opts(s, seq); break; + case STATMOUNT_FS_SUBTYPE: + sm->fs_subtype =3D seq->count; + statmount_fs_subtype(s, seq); + if (seq->count =3D=3D sm->fs_subtype) + return 0; + break; default: WARN_ON_ONCE(true); return -EINVAL; @@ -5203,6 +5217,9 @@ static int do_statmount(struct kstatmount *s, u64 mnt= _id, u64 mnt_ns_id, if (!err && s->mask & STATMOUNT_MNT_OPTS) err =3D statmount_string(s, STATMOUNT_MNT_OPTS); =20 + if (!err && s->mask & STATMOUNT_FS_SUBTYPE) + err =3D statmount_string(s, STATMOUNT_FS_SUBTYPE); + if (!err && s->mask & STATMOUNT_MNT_NS_ID) statmount_mnt_ns_id(s, ns); =20 @@ -5224,7 +5241,7 @@ 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_TYPE | STATMOUNT_MNT_OPTS | STATMOUNT_FS_SUBTYPE) =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 225bc366ffcbf0319929e2f55f1fbea88e4d7b81..fa206fb56b3b25cf80f7d430e1b= 6bab19c3220e4 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -173,7 +173,9 @@ struct statmount { __u32 mnt_root; /* [str] Root of mount relative to root of fs */ __u32 mnt_point; /* [str] Mountpoint relative to current root */ __u64 mnt_ns_id; /* ID of the mount namespace */ - __u64 __spare2[49]; + __u32 fs_subtype; /* [str] Subtype of fs_type (if any) */ + __u32 __spare1[1]; + __u64 __spare2[48]; char str[]; /* Variable size part containing strings */ }; =20 @@ -207,6 +209,7 @@ struct mnt_id_req { #define STATMOUNT_FS_TYPE 0x00000020U /* Want/got fs_type */ #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 */ =20 /* * Special @mnt_id values that can be passed to listmount --=20 2.47.0