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[212.96.48.140]) by smtp.gmail.com with ESMTPSA id p89-v6sm55286201wrc.97.2018.09.20.08.12.26 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 20 Sep 2018 08:12:27 -0700 (PDT) From: Miklos Szeredi To: David Howells Cc: Al Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5/6] fsmount: do not use legacy MS_ flags Date: Thu, 20 Sep 2018 17:12:13 +0200 Message-Id: <20180920151214.15484-6-mszeredi@redhat.com> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180920151214.15484-1-mszeredi@redhat.com> References: <20180920151214.15484-1-mszeredi@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP What happens if we introduce new flags for fsmount(2) and are already out of flags for mount(2)? I see a big mess that way. So let's instead start a clean new set, to be used in the new API. The MS_RELATIME flag was accepted but ignored. Simply leave this out of the new set, since "relatime" is the default. The MNT_ prefix is already used by libmount, and we don't want any confusion arising from that. MOUNT_ feels a bit too long, so just go with the short and sweet M_ prefix. Signed-off-by: Miklos Szeredi --- fs/namespace.c | 28 +++++++++++++--------------- include/uapi/linux/mount.h | 9 +++++++++ 2 files changed, 22 insertions(+), 15 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 7671c1f6fc22..027b99b993c0 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3332,7 +3332,7 @@ EXPORT_SYMBOL_GPL(kern_mount); * Create a kernel mount representation for a new, prepared superblock * (specified by fs_fd) and attach to an open_tree-like file descriptor. */ -SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, unsigned int, ms_flags) +SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, unsigned int, m_flags) { struct fs_context *fc; struct file *file; @@ -3347,30 +3347,28 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, unsigned int, ms_flags if ((flags & ~(FSMOUNT_CLOEXEC)) != 0) return -EINVAL; - if (ms_flags & ~(MS_RDONLY | MS_NOSUID | MS_NODEV | MS_NOEXEC | - MS_NOATIME | MS_NODIRATIME | MS_RELATIME | - MS_STRICTATIME)) + if (m_flags & ~(M_RDONLY | M_NOSUID | M_NODEV | M_NOEXEC | + M_NOATIME | M_STRICTATIME | M_NODIRATIME)) return -EINVAL; - if (ms_flags & MS_RDONLY) + if ((m_flags & M_STRICTATIME) && (m_flags & M_NOATIME)) + return -EINVAL; + + if (m_flags & M_RDONLY) mnt_flags |= MNT_READONLY; - if (ms_flags & MS_NOSUID) + if (m_flags & M_NOSUID) mnt_flags |= MNT_NOSUID; - if (ms_flags & MS_NODEV) + if (m_flags & M_NODEV) mnt_flags |= MNT_NODEV; - if (ms_flags & MS_NOEXEC) + if (m_flags & M_NOEXEC) mnt_flags |= MNT_NOEXEC; - if (ms_flags & MS_NODIRATIME) + if (m_flags & M_NODIRATIME) mnt_flags |= MNT_NODIRATIME; - if (ms_flags & MS_STRICTATIME) { - if (ms_flags & MS_NOATIME) - return -EINVAL; - } else if (ms_flags & MS_NOATIME) { + if (m_flags & M_NOATIME) mnt_flags |= MNT_NOATIME; - } else { + else if (!(m_flags & M_STRICTATIME)) mnt_flags |= MNT_RELATIME; - } f = fdget(fs_fd); if (!f.file) diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h index 3634e065836c..fce3513fc242 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -1,6 +1,15 @@ #ifndef _UAPI_LINUX_MOUNT_H #define _UAPI_LINUX_MOUNT_H +/* Mount flags passed to fsmount(2) */ +#define M_RDONLY 0x01 +#define M_NOSUID 0x02 +#define M_NODEV 0x04 +#define M_NOEXEC 0x08 +#define M_NOATIME 0x10 +#define M_STRICTATIME 0x20 +#define M_NODIRATIME 0x40 + /* * These are the fs-independent mount-flags: up to 32 flags are supported *