Revert "ANDROID: mnt: Add filesystem private data to mount points"

This reverts commit 8e31748d2c
(change Ie769d7b3bb2f5972afe05c1bf16cf88c91647ab2).

This is no longer needed because the only user of vfsmount::data was
sdcardfs, and sdcardfs has now been removed.

Bug: 157700134
Change-Id: I1af6d917288e80b8fec5abcb27bd896078cecf30
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

fs/namespace.c

@@ -198,7 +198,6 @@ static struct mount *alloc_vfsmnt(const char *name)
 		mnt->mnt_count = 1;
 		mnt->mnt_writers = 0;
 #endif
-		mnt->mnt.data = NULL;
 
 		INIT_HLIST_NODE(&mnt->mnt_hash);
 		INIT_LIST_HEAD(&mnt->mnt_child);
@@ -548,7 +547,6 @@ int sb_prepare_remount_readonly(struct super_block *sb)
 
 static void free_vfsmnt(struct mount *mnt)
 {
-	kfree(mnt->mnt.data);
 	kfree_const(mnt->mnt_devname);
 #ifdef CONFIG_SMP
 	free_percpu(mnt->mnt_pcp);
@@ -959,15 +957,6 @@ struct vfsmount *vfs_create_mount(struct fs_context *fc)
 	if (!mnt)
 		return ERR_PTR(-ENOMEM);
 
-	if (fc->fs_type->alloc_mnt_data) {
-		mnt->mnt.data = fc->fs_type->alloc_mnt_data();
-		if (!mnt->mnt.data) {
-			mnt_free_id(mnt);
-			free_vfsmnt(mnt);
-			return ERR_PTR(-ENOMEM);
-		}
-		fc->root->d_sb->s_op->update_mnt_data(mnt->mnt.data, fc);
-	}
 	if (fc->sb_flags & SB_KERNMOUNT)
 		mnt->mnt.mnt_flags = MNT_INTERNAL;
 
@@ -1051,14 +1040,6 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
 	if (!mnt)
 		return ERR_PTR(-ENOMEM);
 
-	if (sb->s_op->clone_mnt_data) {
-		mnt->mnt.data = sb->s_op->clone_mnt_data(old->mnt.data);
-		if (!mnt->mnt.data) {
-			err = -ENOMEM;
-			goto out_free;
-		}
-	}
-
 	if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE))
 		mnt->mnt_group_id = 0; /* not a peer of original */
 	else
@@ -2629,15 +2610,8 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags,
 		err = -EPERM;
 		if (ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
 			err = reconfigure_super(fc);
-			if (!err) {
+			if (!err)
-				sb->s_op->update_mnt_data(mnt->mnt.data, fc);
 				set_mount_attributes(mnt, mnt_flags);
-				namespace_lock();
-				lock_mount_hash();
-				propagate_remount(mnt);
-				unlock_mount_hash();
-				namespace_unlock();
-			}
 		}
 		up_write(&sb->s_umount);
 	}

fs/pnode.c

@@ -600,19 +600,3 @@ int propagate_umount(struct list_head *list)
 
 	return 0;
 }
-
-void propagate_remount(struct mount *mnt)
-{
-	struct mount *parent = mnt->mnt_parent;
-	struct mount *p = mnt, *m;
-	struct super_block *sb = mnt->mnt.mnt_sb;
-
-	if (!sb->s_op->copy_mnt_data)
-		return;
-	for (p = propagation_next(parent, parent); p;
-				p = propagation_next(p, parent)) {
-		m = __lookup_mnt(&p->mnt, mnt->mnt_mountpoint);
-		if (m)
-			sb->s_op->copy_mnt_data(m->mnt.data, mnt->mnt.data);
-	}
-}

fs/pnode.h

@@ -42,7 +42,6 @@ int propagate_mnt(struct mount *, struct mountpoint *, struct mount *,
 int propagate_umount(struct list_head *);
 int propagate_mount_busy(struct mount *, int);
 void propagate_mount_unlock(struct mount *);
-void propagate_remount(struct mount *);
 void mnt_release_group_id(struct mount *);
 int get_dominating_id(struct mount *mnt, const struct path *root);
 unsigned int mnt_get_count(struct mount *mnt);

include/linux/fs.h

@@ -1931,9 +1931,6 @@ struct super_operations {
 	int (*unfreeze_fs) (struct super_block *);
 	int (*statfs) (struct dentry *, struct kstatfs *);
 	int (*remount_fs) (struct super_block *, int *, char *);
-	void *(*clone_mnt_data) (void *);
-	void (*copy_mnt_data) (void *, void *);
-	void (*update_mnt_data) (void *, struct fs_context *);
 	void (*umount_begin) (struct super_block *);
 
 	int (*show_options)(struct seq_file *, struct dentry *);
@@ -2220,7 +2217,6 @@ struct file_system_type {
 	const struct fs_parameter_spec *parameters;
 	struct dentry *(*mount) (struct file_system_type *, int,
 		       const char *, void *);
-	void *(*alloc_mnt_data) (void);
 	void (*kill_sb) (struct super_block *);
 	struct module *owner;
 	struct file_system_type * next;

include/linux/mount.h

@@ -71,7 +71,6 @@ struct vfsmount {
 	struct dentry *mnt_root;	/* root of the mounted tree */
 	struct super_block *mnt_sb;	/* pointer to superblock */
 	int mnt_flags;
-	void *data;
 } __randomize_layout;
 
 struct file; /* forward dec */