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 <mszeredi@xxxxxxxxxx>
---
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
*
--
2.14.3
