From: Ram Pai <linuxram@us.ibm.com>
Date: Mon, 7 Nov 2005 22:19:07 +0000 (-0500)
Subject: [PATCH] beginning of the shared-subtree proper
X-Git-Tag: v2.6.15-rc1~432
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07b20889e3052c7e77d6a6a54e7e83446eb1ba84;p=pandora-kernel.git

[PATCH] beginning of the shared-subtree proper

A private mount does not forward or receive propagation.  This patch
provides user the ability to convert any mount to private.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/fs/Makefile b/fs/Makefile
index 1972da186272..4c2655759078 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -10,7 +10,7 @@ obj-y :=	open.o read_write.o file_table.o buffer.o  bio.o super.o \
 		ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
 		attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
 		seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
-		ioprio.o
+		ioprio.o pnode.o
 
 obj-$(CONFIG_INOTIFY)		+= inotify.o
 obj-$(CONFIG_EPOLL)		+= eventpoll.o
diff --git a/fs/namespace.c b/fs/namespace.c
index 4abee9ab009f..3782923d6d4d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -24,6 +24,7 @@
 #include <linux/mount.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
+#include "pnode.h"
 
 extern int __init init_rootfs(void);
 
@@ -662,6 +663,27 @@ out_unlock:
 	return err;
 }
 
+/*
+ * recursively change the type of the mountpoint.
+ */
+static int do_change_type(struct nameidata *nd, int flag)
+{
+	struct vfsmount *m, *mnt = nd->mnt;
+	int recurse = flag & MS_REC;
+	int type = flag & ~MS_REC;
+
+	if (nd->dentry != nd->mnt->mnt_root)
+		return -EINVAL;
+
+	down_write(&namespace_sem);
+	spin_lock(&vfsmount_lock);
+	for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
+		change_mnt_propagation(m, type);
+	spin_unlock(&vfsmount_lock);
+	up_write(&namespace_sem);
+	return 0;
+}
+
 /*
  * do loopback mount.
  */
@@ -1091,6 +1113,8 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 				    data_page);
 	else if (flags & MS_BIND)
 		retval = do_loopback(&nd, dev_name, flags & MS_REC);
+	else if (flags & MS_PRIVATE)
+		retval = do_change_type(&nd, flags);
 	else if (flags & MS_MOVE)
 		retval = do_move_mount(&nd, dev_name);
 	else
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