Don't leak mount flags into kernel

[zfs.git] / lib / libspl / include / sys / mount.h

diff --git a/lib/libspl/include/sys/mount.h b/lib/libspl/include/sys/mount.h
index 144f915..7b1e06b 100644 (file)
--- a/lib/libspl/include/sys/mount.h
+++ b/lib/libspl/include/sys/mount.h
@@ -42,9 +42,42 @@
 #define BLKGETSIZE64           _IOR(0x12, 114, size_t)
 #endif
 
-#define MS_FORCE               MNT_FORCE
-#define MS_OVERLAY             32768
-#define MS_NOMNTTAB            0         /* Not supported in Linux */
-#define MS_OPTIONSTR           0         /* Not necessary in Linux */
+/*
+ * Some old glibc headers don't correctly define MS_DIRSYNC and
+ * instead use the enum name S_WRITE.  When using these older
+ * headers define MS_DIRSYNC to be S_WRITE.
+ */
+#if !defined(MS_DIRSYNC)
+#define MS_DIRSYNC             S_WRITE
+#endif
+
+#define        MS_USERS        (MS_NOEXEC|MS_NOSUID|MS_NODEV)
+#define        MS_OWNER        (MS_NOSUID|MS_NODEV)
+#define        MS_GROUP        (MS_NOSUID|MS_NODEV)
+#define        MS_COMMENT      0
+
+/*
+ * Older glibc <sys/mount.h> headers did not define all the available
+ * umount2(2) flags.  Both MNT_FORCE and MNT_DETACH are supported in the
+ * kernel back to 2.4.11 so we define them correctly if they are missing.
+ */
+#ifdef MNT_FORCE
+# define MS_FORCE      MNT_FORCE
+#else
+# define MS_FORCE      0x00000001
+#endif /* MNT_FORCE */
+
+#ifdef MNT_DETACH
+# define MS_DETACH     MNT_DETACH
+#else
+# define MS_DETACH     0x00000002
+#endif /* MNT_DETACH */
+
+/*
+ * Overlay mount is default in Linux, but for solaris/zfs
+ * compatibility, MS_OVERLAY is defined to explicitly have the user
+ * provide a flag (-O) to mount over a non empty directory.
+ */
+#define MS_OVERLAY      0x00000004
 
 #endif /* _LIBSPL_SYS_MOUNT_H */