From: Harald Hoyer <harald@redhat.com>
Date: Mon, 14 Nov 2011 13:11:01 +0000 (+0100)
Subject: switch_root: umount mount points we cannot move with MNT_DETACH
X-Git-Tag: v2.21-rc1~187
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=944de78b5d83e548f7c428ef5c08c69e6984cc4f;p=thirdparty%2Futil-linux.git

switch_root: umount mount points we cannot move with MNT_DETACH

If a mount point cannot be moved to the new root, umount it with
MNT_DETACH, so that it is lazy umounted and does not show up in
/proc/mounts anymore.

[kzak@redhat.com: - add MNT_DETACH macro fallback]

Signed-off-by: Harald Hoyer <harald@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/sys-utils/switch_root.c b/sys-utils/switch_root.c
index e50f3101a5..1c7375dbed 100644
--- a/sys-utils/switch_root.c
+++ b/sys-utils/switch_root.c
@@ -40,6 +40,10 @@
 #define MS_MOVE 8192
 #endif
 
+#ifndef MNT_DETACH
+#define MNT_DETACH       0x00000002	/* Just detach from the tree */
+#endif
+
 /* remove all files/directories below dirName -- don't cross mountpoints */
 static int recursiveRemove(int fd)
 {
@@ -131,7 +135,7 @@ static int switchroot(const char *newroot)
 
 		if ((stat(newmount, &sb) != 0) || (sb.st_dev != newroot_stat.st_dev)) {
 			/* mount point seems to be mounted already or stat failed */
-			umount(umounts[i]);
+			umount2(umounts[i], MNT_DETACH);
 			continue;
 		}