Add documentation for exported functions and types

Signed-off-by: Jamie Hannaford <jamie.hannaford@rackspace.com>

mount/flags_linux.go

@@ -5,26 +5,81 @@ import (
 )
 
 const (
-	RDONLY      = syscall.MS_RDONLY
-	NOSUID      = syscall.MS_NOSUID
-	NODEV       = syscall.MS_NODEV
-	NOEXEC      = syscall.MS_NOEXEC
+	// RDONLY will mount the file system read-only.
+	RDONLY = syscall.MS_RDONLY
+
+	// NOSUID will not allow set-user-identifier or set-group-identifier bits to
+	// take effect.
+	NOSUID = syscall.MS_NOSUID
+
+	// NODEV will not interpret character or block special devices on the file
+	// system.
+	NODEV = syscall.MS_NODEV
+
+	// NOEXEC will not allow execution of any binaries on the mounted file system.
+	NOEXEC = syscall.MS_NOEXEC
+
+	// SYNCHRONOUS will allow I/O to the file system to be done synchronously.
 	SYNCHRONOUS = syscall.MS_SYNCHRONOUS
-	DIRSYNC     = syscall.MS_DIRSYNC
-	REMOUNT     = syscall.MS_REMOUNT
-	MANDLOCK    = syscall.MS_MANDLOCK
-	NOATIME     = syscall.MS_NOATIME
-	NODIRATIME  = syscall.MS_NODIRATIME
-	BIND        = syscall.MS_BIND
-	RBIND       = syscall.MS_BIND | syscall.MS_REC
-	UNBINDABLE  = syscall.MS_UNBINDABLE
+
+	// DIRSYNC will force all directory updates within the file system to be done
+	// synchronously. This affects the following system calls: creat, link,
+	// unlink, symlink, mkdir, rmdir, mknod and rename.
+	DIRSYNC = syscall.MS_DIRSYNC
+
+	// REMOUNT will attempt to remount an already-mounted file system. This is
+	// commonly used to change the mount flags for a file system, especially to
+	// make a readonly file system writeable. It does not change device or mount
+	// point.
+	REMOUNT = syscall.MS_REMOUNT
+
+	// MANDLOCK will force mandatory locks on a filesystem.
+	MANDLOCK = syscall.MS_MANDLOCK
+
+	// NOATIME will not update the file access time when reading from a file.
+	NOATIME = syscall.MS_NOATIME
+
+	// NODIRATIME will not update the directory access time.
+	NODIRATIME = syscall.MS_NODIRATIME
+
+	// BIND remounts a subtree somewhere else.
+	BIND = syscall.MS_BIND
+
+	// RBIND remounts a subtree and all possible submounts somewhere else.
+	RBIND = syscall.MS_BIND | syscall.MS_REC
+
+	// UNBINDABLE creates a mount which cannot be cloned through a bind operation.
+	UNBINDABLE = syscall.MS_UNBINDABLE
+
+	// RUNBINDABLE marks the entire mount tree as UNBINDABLE.
 	RUNBINDABLE = syscall.MS_UNBINDABLE | syscall.MS_REC
-	PRIVATE     = syscall.MS_PRIVATE
-	RPRIVATE    = syscall.MS_PRIVATE | syscall.MS_REC
-	SLAVE       = syscall.MS_SLAVE
-	RSLAVE      = syscall.MS_SLAVE | syscall.MS_REC
-	SHARED      = syscall.MS_SHARED
-	RSHARED     = syscall.MS_SHARED | syscall.MS_REC
-	RELATIME    = syscall.MS_RELATIME
+
+	// PRIVATE creates a mount which carries no propagation abilities.
+	PRIVATE = syscall.MS_PRIVATE
+
+	// RPRIVATE marks the entire mount tree as PRIVATE.
+	RPRIVATE = syscall.MS_PRIVATE | syscall.MS_REC
+
+	// SLAVE creates a mount which receives propagation from its master, but not
+	// vice versa.
+	SLAVE = syscall.MS_SLAVE
+
+	// RSLAVE marks the entire mount tree as SLAVE.
+	RSLAVE = syscall.MS_SLAVE | syscall.MS_REC
+
+	// SHARED creates a mount which provides the ability to create mirrors of
+	// that mount such that mounts and unmounts within any of the mirrors
+	// propagate to the other mirrors.
+	SHARED = syscall.MS_SHARED
+
+	// RSHARED marks the entire mount tree as SHARED.
+	RSHARED = syscall.MS_SHARED | syscall.MS_REC
+
+	// RELATIME updates inode access times relative to modify or change time.
+	RELATIME = syscall.MS_RELATIME
+
+	// STRICTATIME allows to explicitly request full atime updates.  This makes
+	// it possible for the kernel to default to relatime or noatime but still
+	// allow userspace to override it.
 	STRICTATIME = syscall.MS_STRICTATIME
 )