1 files changed, 58 insertions, 17 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index c7cb8a526c05..0570729c87fd 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1361,6 +1361,36 @@ enum umount_tree_flags {
 	UMOUNT_PROPAGATE = 2,
 	UMOUNT_CONNECTED = 4,
 };
+
+static bool disconnect_mount(struct mount *mnt, enum umount_tree_flags how)
+{
+	/* Leaving mounts connected is only valid for lazy umounts */
+	if (how & UMOUNT_SYNC)
+		return true;
+
+	/* A mount without a parent has nothing to be connected to */
+	if (!mnt_has_parent(mnt))
+		return true;
+
+	/* Because the reference counting rules change when mounts are
+	 * unmounted and connected, umounted mounts may not be
+	 * connected to mounted mounts.
+	 */
+	if (!(mnt->mnt_parent->mnt.mnt_flags & MNT_UMOUNT))
+		return true;
+
+	/* Has it been requested that the mount remain connected? */
+	if (how & UMOUNT_CONNECTED)
+		return false;
+
+	/* Is the mount locked such that it needs to remain connected? */
+	if (IS_MNT_LOCKED(mnt))
+		return false;
+
+	/* By default disconnect the mount */
+	return true;
+}
+
 /*
  * mount_lock must be held
  * namespace_sem must be held for write
@@ -1398,10 +1428,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
 		if (how & UMOUNT_SYNC)
 			p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
 
-		disconnect = !(((how & UMOUNT_CONNECTED) &&
-				mnt_has_parent(p) &&
-				(p->mnt_parent->mnt.mnt_flags & MNT_UMOUNT)) ||
-			       IS_MNT_LOCKED_AND_LAZY(p));
+		disconnect = disconnect_mount(p, how);
 
 		pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt,
 				 disconnect ? &unmounted : NULL);
@@ -1538,11 +1565,8 @@ void __detach_mounts(struct dentry *dentry)
 	while (!hlist_empty(&mp->m_list)) {
 		mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
 		if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
-			struct mount *p, *tmp;
-			list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts,  mnt_child) {
-				hlist_add_head(&p->mnt_umount.s_list, &unmounted);
-				umount_mnt(p);
-			}
+			hlist_add_head(&mnt->mnt_umount.s_list, &unmounted);
+			umount_mnt(mnt);
 		}
 		else umount_tree(mnt, UMOUNT_CONNECTED);
 	}
@@ -3194,6 +3218,8 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
 	down_read(&namespace_sem);
 	list_for_each_entry(mnt, &ns->list, mnt_list) {
 		struct mount *child;
+		int mnt_flags;
+
 		if (mnt->mnt.mnt_sb->s_type != type)
 			continue;
 
@@ -3203,17 +3229,30 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
 		if (mnt->mnt.mnt_root != mnt->mnt.mnt_sb->s_root)
 			continue;
 
+		/* Read the mount flags and filter out flags that
+		 * may safely be ignored.
+		 */
+		mnt_flags = mnt->mnt.mnt_flags;
+		if (mnt->mnt.mnt_sb->s_iflags & SB_I_NOEXEC)
+			mnt_flags &= ~(MNT_LOCK_NOSUID | MNT_LOCK_NOEXEC);
+
 		/* Verify the mount flags are equal to or more permissive
 		 * than the proposed new mount.
 		 */
-		if ((mnt->mnt.mnt_flags & MNT_LOCK_READONLY) &&
+		if ((mnt_flags & MNT_LOCK_READONLY) &&
 		    !(new_flags & MNT_READONLY))
 			continue;
-		if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
+		if ((mnt_flags & MNT_LOCK_NODEV) &&
 		    !(new_flags & MNT_NODEV))
 			continue;
-		if ((mnt->mnt.mnt_flags & MNT_LOCK_ATIME) &&
-		    ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK)))
+		if ((mnt_flags & MNT_LOCK_NOSUID) &&
+		    !(new_flags & MNT_NOSUID))
+			continue;
+		if ((mnt_flags & MNT_LOCK_NOEXEC) &&
+		    !(new_flags & MNT_NOEXEC))
+			continue;
+		if ((mnt_flags & MNT_LOCK_ATIME) &&
+		    ((mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK)))
 			continue;
 
 		/* This mount is not fully visible if there are any
@@ -3223,16 +3262,18 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
 		list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
 			struct inode *inode = child->mnt_mountpoint->d_inode;
 			/* Only worry about locked mounts */
-			if (!(mnt->mnt.mnt_flags & MNT_LOCKED))
+			if (!(mnt_flags & MNT_LOCKED))
 				continue;
 			/* Is the directory permanetly empty? */
 			if (!is_empty_dir_inode(inode))
 				goto next;
 		}
 		/* Preserve the locked attributes */
-		*new_mnt_flags |= mnt->mnt.mnt_flags & (MNT_LOCK_READONLY | \
-							MNT_LOCK_NODEV    | \
-							MNT_LOCK_ATIME);
+		*new_mnt_flags |= mnt_flags & (MNT_LOCK_READONLY | \
+					       MNT_LOCK_NODEV    | \
+					       MNT_LOCK_NOSUID   | \
+					       MNT_LOCK_NOEXEC   | \
+					       MNT_LOCK_ATIME);
 		visible = true;
 		goto found;
 	next:	;