fsnotify/vfsmount: add fsnotify fields to struct vfsmount

This patch adds the list and mask fields needed to support vfsmount marks.
These are the same fields fsnotify needs on an inode.  They are not used,
just declared and we note where the cleanup hook should be (the function is
not yet defined)

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>

fs/namespace.c

@@ -29,6 +29,7 @@
 #include <linux/log2.h>
 #include <linux/idr.h>
 #include <linux/fs_struct.h>
+#include <linux/fsnotify.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include "pnode.h"
@@ -150,6 +151,9 @@ struct vfsmount *alloc_vfsmnt(const char *name)
 		INIT_LIST_HEAD(&mnt->mnt_share);
 		INIT_LIST_HEAD(&mnt->mnt_slave_list);
 		INIT_LIST_HEAD(&mnt->mnt_slave);
+#ifdef CONFIG_FSNOTIFY
+		INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks);
+#endif
 #ifdef CONFIG_SMP
 		mnt->mnt_writers = alloc_percpu(int);
 		if (!mnt->mnt_writers)

fs/notify/fsnotify.c

@@ -163,9 +163,7 @@ static bool needed_by_vfsmount(__u32 test_mask, struct vfsmount *mnt)
 	if (!mnt)
 		return false;
 
-	/* hook in this when mnt->mnt_fsnotify_mask is defined */
-	/* return (test_mask & path->mnt->mnt_fsnotify_mask); */
-	return false;
+	return (test_mask & mnt->mnt_fsnotify_mask);
 }
 /*
  * This is the main call to fsnotify.  The VFS calls into hook specific functions

include/linux/mount.h

@@ -56,7 +56,11 @@ struct vfsmount {
 	struct list_head mnt_mounts;	/* list of children, anchored here */
 	struct list_head mnt_child;	/* and going through their mnt_child */
 	int mnt_flags;
-	/* 4 bytes hole on 64bits arches */
+	/* 4 bytes hole on 64bits arches without fsnotify */
+#ifdef CONFIG_FSNOTIFY
+	__u32 mnt_fsnotify_mask;
+	struct hlist_head mnt_fsnotify_marks;
+#endif
 	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
 	struct list_head mnt_list;
 	struct list_head mnt_expire;	/* link in fs-specific expiry list */