Merge tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.

That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).

Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.

The end result this series is aiming for:

- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.

- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().

Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.

This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.

Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"

* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...

Documentation/filesystems/porting.rst

···
 dentry and doesn't provide a replacement, it also unlocks the parent.
 Consequently the return value from vfs_mkdir() can be passed to
 end_creating() and the parent will be unlocked precisely when necessary.
+
+---
+
+**mandatory**
+
+kill_litter_super() is gone; convert to DCACHE_PERSISTENT use (as all
+in-tree filesystems have done).

arch/powerpc/platforms/cell/spufs/inode.c

···
 	inode->i_fop = fops;
 	inode->i_size = size;
 	inode->i_private = SPUFS_I(inode)->i_ctx = get_spu_context(ctx);
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
 out:
 	return ret;
 }
···
 			return -ENOMEM;
 		ret = spufs_new_file(dir->d_sb, dentry, files->ops,
 					files->mode & mode, files->size, ctx);
-		if (ret) {
-			dput(dentry);
+		dput(dentry);
+		if (ret)
 			return ret;
-		}
 		files++;
 	}
 	return 0;
···
 
 	inode_lock(inode);
 
-	dget(dentry);
 	inc_nlink(dir);
 	inc_nlink(inode);
 
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 
 	if (flags & SPU_CREATE_NOSCHED)
 		ret = spufs_fill_dir(dentry, spufs_dir_nosched_contents,
···
 	inode->i_op = &simple_dir_inode_operations;
 	inode->i_fop = &simple_dir_operations;
 
-	d_instantiate(dentry, inode);
-	dget(dentry);
 	inc_nlink(dir);
-	inc_nlink(d_inode(dentry));
+	inc_nlink(inode);
+	d_make_persistent(dentry, inode);
 	return ret;
 
 out_iput:
···
 	.name = "spufs",
 	.init_fs_context = spufs_init_fs_context,
 	.parameters	= spufs_fs_parameters,
-	.kill_sb = kill_litter_super,
+	.kill_sb = kill_anon_super,
 };
 MODULE_ALIAS_FS("spufs");
 

arch/s390/hypfs/hypfs.h

···
 
 extern struct dentry *hypfs_mkdir(struct dentry *parent, const char *name);
 
-extern struct dentry *hypfs_create_u64(struct dentry *dir, const char *name,
-				       __u64 value);
+extern int hypfs_create_u64(struct dentry *dir, const char *name, __u64 value);
 
-extern struct dentry *hypfs_create_str(struct dentry *dir, const char *name,
-				       char *string);
+extern int hypfs_create_str(struct dentry *dir, const char *name, char *string);
 
 /* LPAR Hypervisor */
 extern int hypfs_diag_init(void);

arch/s390/hypfs/hypfs_diag_fs.c

···
 {
 	struct dentry *cpu_dir;
 	char buffer[TMP_SIZE];
-	void *rc;
+	int rc;
 
 	snprintf(buffer, TMP_SIZE, "%d", cpu_info__cpu_addr(diag204_get_info_type(),
 							    cpu_info));
···
 	rc = hypfs_create_u64(cpu_dir, "mgmtime",
 			      cpu_info__acc_time(diag204_get_info_type(), cpu_info) -
 			      cpu_info__lp_time(diag204_get_info_type(), cpu_info));
-	if (IS_ERR(rc))
-		return PTR_ERR(rc);
+	if (rc)
+		return rc;
 	rc = hypfs_create_u64(cpu_dir, "cputime",
 			      cpu_info__lp_time(diag204_get_info_type(), cpu_info));
-	if (IS_ERR(rc))
-		return PTR_ERR(rc);
+	if (rc)
+		return rc;
 	if (diag204_get_info_type() == DIAG204_INFO_EXT) {
 		rc = hypfs_create_u64(cpu_dir, "onlinetime",
 				      cpu_info__online_time(diag204_get_info_type(),
 							    cpu_info));
-		if (IS_ERR(rc))
-			return PTR_ERR(rc);
+		if (rc)
+			return rc;
 	}
 	diag224_idx2name(cpu_info__ctidx(diag204_get_info_type(), cpu_info), buffer);
-	rc = hypfs_create_str(cpu_dir, "type", buffer);
-	return PTR_ERR_OR_ZERO(rc);
+	return hypfs_create_str(cpu_dir, "type", buffer);
 }
 
 static void *hypfs_create_lpar_files(struct dentry *systems_dir, void *part_hdr)
···
 {
 	struct dentry *cpu_dir;
 	char buffer[TMP_SIZE];
-	void *rc;
+	int rc;
 
 	snprintf(buffer, TMP_SIZE, "%i", phys_cpu__cpu_addr(diag204_get_info_type(),
 							    cpu_info));
···
 		return PTR_ERR(cpu_dir);
 	rc = hypfs_create_u64(cpu_dir, "mgmtime",
 			      phys_cpu__mgm_time(diag204_get_info_type(), cpu_info));
-	if (IS_ERR(rc))
-		return PTR_ERR(rc);
+	if (rc)
+		return rc;
 	diag224_idx2name(phys_cpu__ctidx(diag204_get_info_type(), cpu_info), buffer);
-	rc = hypfs_create_str(cpu_dir, "type", buffer);
-	return PTR_ERR_OR_ZERO(rc);
+	return hypfs_create_str(cpu_dir, "type", buffer);
 }
 
 static void *hypfs_create_phys_files(struct dentry *parent_dir, void *phys_hdr)
···
 		return rc;
 
 	systems_dir = hypfs_mkdir(root, "systems");
-	if (IS_ERR(systems_dir)) {
-		rc = PTR_ERR(systems_dir);
-		goto err_out;
-	}
+	if (IS_ERR(systems_dir))
+		return PTR_ERR(systems_dir);
 	time_hdr = (struct x_info_blk_hdr *)buffer;
 	part_hdr = time_hdr + info_blk_hdr__size(diag204_get_info_type());
 	for (i = 0; i < info_blk_hdr__npar(diag204_get_info_type(), time_hdr); i++) {
 		part_hdr = hypfs_create_lpar_files(systems_dir, part_hdr);
-		if (IS_ERR(part_hdr)) {
-			rc = PTR_ERR(part_hdr);
-			goto err_out;
-		}
+		if (IS_ERR(part_hdr))
+			return PTR_ERR(part_hdr);
 	}
 	if (info_blk_hdr__flags(diag204_get_info_type(), time_hdr) &
 	    DIAG204_LPAR_PHYS_FLG) {
 		ptr = hypfs_create_phys_files(root, part_hdr);
-		if (IS_ERR(ptr)) {
-			rc = PTR_ERR(ptr);
-			goto err_out;
-		}
+		if (IS_ERR(ptr))
+			return PTR_ERR(ptr);
 	}
 	hyp_dir = hypfs_mkdir(root, "hyp");
-	if (IS_ERR(hyp_dir)) {
-		rc = PTR_ERR(hyp_dir);
-		goto err_out;
-	}
-	ptr = hypfs_create_str(hyp_dir, "type", "LPAR Hypervisor");
-	if (IS_ERR(ptr)) {
-		rc = PTR_ERR(ptr);
-		goto err_out;
-	}
-	rc = 0;
-
-err_out:
-	return rc;
+	if (IS_ERR(hyp_dir))
+		return PTR_ERR(hyp_dir);
+	return hypfs_create_str(hyp_dir, "type", "LPAR Hypervisor");
 }
 
 /* Diagnose 224 functions */

arch/s390/hypfs/hypfs_vm_fs.c

···
 
 #define ATTRIBUTE(dir, name, member) \
 do { \
-	void *rc; \
-	rc = hypfs_create_u64(dir, name, member); \
-	if (IS_ERR(rc)) \
-		return PTR_ERR(rc); \
+	int rc = hypfs_create_u64(dir, name, member); \
+	if (rc) \
+		return rc; \
 } while (0)
 
 static int hypfs_vm_create_guest(struct dentry *systems_dir,
···
 
 int hypfs_vm_create_files(struct dentry *root)
 {
-	struct dentry *dir, *file;
+	struct dentry *dir;
 	struct diag2fc_data *data;
 	unsigned int count = 0;
 	int rc, i;
···
 		rc = PTR_ERR(dir);
 		goto failed;
 	}
-	file = hypfs_create_str(dir, "type", "z/VM Hypervisor");
-	if (IS_ERR(file)) {
-		rc = PTR_ERR(file);
+	rc = hypfs_create_str(dir, "type", "z/VM Hypervisor");
+	if (rc)
 		goto failed;
-	}
 
 	/* physical cpus */
 	dir = hypfs_mkdir(root, "cpus");
···
 		rc = PTR_ERR(dir);
 		goto failed;
 	}
-	file = hypfs_create_u64(dir, "count", data->lcpus);
-	if (IS_ERR(file)) {
-		rc = PTR_ERR(file);
+	rc = hypfs_create_u64(dir, "count", data->lcpus);
+	if (rc)
 		goto failed;
-	}
 
 	/* guests */
 	dir = hypfs_mkdir(root, "systems");

arch/s390/hypfs/inode.c

···
 
 static void hypfs_add_dentry(struct dentry *dentry)
 {
-	dentry->d_fsdata = hypfs_last_dentry;
-	hypfs_last_dentry = dentry;
-}
-
-static void hypfs_remove(struct dentry *dentry)
-{
-	struct dentry *parent;
-
-	parent = dentry->d_parent;
-	inode_lock(d_inode(parent));
-	if (simple_positive(dentry)) {
-		if (d_is_dir(dentry))
-			simple_rmdir(d_inode(parent), dentry);
-		else
-			simple_unlink(d_inode(parent), dentry);
+	if (IS_ROOT(dentry->d_parent)) {
+		dentry->d_fsdata = hypfs_last_dentry;
+		hypfs_last_dentry = dentry;
 	}
-	d_drop(dentry);
-	dput(dentry);
-	inode_unlock(d_inode(parent));
 }
 
-static void hypfs_delete_tree(struct dentry *root)
+static void hypfs_delete_tree(void)
 {
 	while (hypfs_last_dentry) {
-		struct dentry *next_dentry;
-		next_dentry = hypfs_last_dentry->d_fsdata;
-		hypfs_remove(hypfs_last_dentry);
+		struct dentry *next_dentry = hypfs_last_dentry->d_fsdata;
+		simple_recursive_removal(hypfs_last_dentry, NULL);
 		hypfs_last_dentry = next_dentry;
 	}
 }
···
 		rc = -EBUSY;
 		goto out;
 	}
-	hypfs_delete_tree(sb->s_root);
+	hypfs_delete_tree();
 	if (machine_is_vm())
 		rc = hypfs_vm_create_files(sb->s_root);
 	else
 		rc = hypfs_diag_create_files(sb->s_root);
 	if (rc) {
 		pr_err("Updating the hypfs tree failed\n");
-		hypfs_delete_tree(sb->s_root);
+		hypfs_delete_tree();
 		goto out;
 	}
 	hypfs_update_update(sb);
···
 {
 	struct hypfs_sb_info *sb_info = sb->s_fs_info;
 
-	if (sb->s_root)
-		hypfs_delete_tree(sb->s_root);
-	if (sb_info && sb_info->update_file)
-		hypfs_remove(sb_info->update_file);
-	kfree(sb->s_fs_info);
-	sb->s_fs_info = NULL;
-	kill_litter_super(sb);
+	hypfs_last_dentry = NULL;
+	kill_anon_super(sb);
+	kfree(sb_info);
 }
 
 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
···
 	struct dentry *dentry;
 	struct inode *inode;
 
-	inode_lock(d_inode(parent));
-	dentry = lookup_noperm(&QSTR(name), parent);
-	if (IS_ERR(dentry)) {
-		dentry = ERR_PTR(-ENOMEM);
-		goto fail;
-	}
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry))
+		return ERR_PTR(-ENOMEM);
 	inode = hypfs_make_inode(parent->d_sb, mode);
 	if (!inode) {
-		dput(dentry);
-		dentry = ERR_PTR(-ENOMEM);
-		goto fail;
+		simple_done_creating(dentry);
+		return ERR_PTR(-ENOMEM);
 	}
 	if (S_ISREG(mode)) {
 		inode->i_fop = &hypfs_file_ops;
···
 	} else
 		BUG();
 	inode->i_private = data;
-	d_instantiate(dentry, inode);
-	dget(dentry);
-fail:
-	inode_unlock(d_inode(parent));
-	return dentry;
+	d_make_persistent(dentry, inode);
+	simple_done_creating(dentry);
+	return dentry;	 // borrowed
 }
 
 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
···
 	return dentry;
 }
 
-struct dentry *hypfs_create_u64(struct dentry *dir,
-				const char *name, __u64 value)
+int hypfs_create_u64(struct dentry *dir, const char *name, __u64 value)
 {
 	char *buffer;
 	char tmp[TMP_SIZE];
···
 	snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
 	buffer = kstrdup(tmp, GFP_KERNEL);
 	if (!buffer)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	dentry =
 	    hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
 	if (IS_ERR(dentry)) {
 		kfree(buffer);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 	hypfs_add_dentry(dentry);
-	return dentry;
+	return 0;
 }
 
-struct dentry *hypfs_create_str(struct dentry *dir,
-				const char *name, char *string)
+int hypfs_create_str(struct dentry *dir, const char *name, char *string)
 {
 	char *buffer;
 	struct dentry *dentry;
 
 	buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
 	if (!buffer)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	sprintf(buffer, "%s\n", string);
 	dentry =
 	    hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
 	if (IS_ERR(dentry)) {
 		kfree(buffer);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 	hypfs_add_dentry(dentry);
-	return dentry;
+	return 0;
 }
 
 static const struct file_operations hypfs_file_ops = {

drivers/android/binder/rust_binderfs.c

···
 	}
 
 	root = sb->s_root;
-	inode_lock(d_inode(root));
-
-	/* look it up */
-	dentry = lookup_noperm(&QSTR(req->name), root);
+	dentry = simple_start_creating(root, req->name);
 	if (IS_ERR(dentry)) {
-		inode_unlock(d_inode(root));
 		ret = PTR_ERR(dentry);
 		goto err;
 	}
 
-	if (d_really_is_positive(dentry)) {
-		/* already exists */
-		dput(dentry);
-		inode_unlock(d_inode(root));
-		ret = -EEXIST;
-		goto err;
-	}
-
 	inode->i_private = device;
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
+
 	fsnotify_create(root->d_inode, dentry);
-	inode_unlock(d_inode(root));
+	simple_done_creating(dentry);
 
 	return 0;
 
···
 	return ret;
 }
 
-static struct dentry *binderfs_create_dentry(struct dentry *parent,
-					     const char *name)
-{
-	struct dentry *dentry;
-
-	dentry = lookup_noperm(&QSTR(name), parent);
-	if (IS_ERR(dentry))
-		return dentry;
-
-	/* Return error if the file/dir already exists. */
-	if (d_really_is_positive(dentry)) {
-		dput(dentry);
-		return ERR_PTR(-EEXIST);
-	}
-
-	return dentry;
-}
-
 void rust_binderfs_remove_file(struct dentry *dentry)
 {
-	struct inode *parent_inode;
-
-	parent_inode = d_inode(dentry->d_parent);
-	inode_lock(parent_inode);
-	if (simple_positive(dentry)) {
-		dget(dentry);
-		simple_unlink(parent_inode, dentry);
-		d_delete(dentry);
-		dput(dentry);
-	}
-	inode_unlock(parent_inode);
+	simple_recursive_removal(dentry, NULL);
 }
 
 static struct dentry *rust_binderfs_create_file(struct dentry *parent, const char *name,
···
 						void *data)
 {
 	struct dentry *dentry;
-	struct inode *new_inode, *parent_inode;
-	struct super_block *sb;
+	struct inode *new_inode;
 
-	parent_inode = d_inode(parent);
-	inode_lock(parent_inode);
-
-	dentry = binderfs_create_dentry(parent, name);
-	if (IS_ERR(dentry))
-		goto out;
-
-	sb = parent_inode->i_sb;
-	new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
-	if (!new_inode) {
-		dput(dentry);
-		dentry = ERR_PTR(-ENOMEM);
-		goto out;
-	}
-
+	new_inode = binderfs_make_inode(parent->d_sb, S_IFREG | 0444);
+	if (!new_inode)
+		return ERR_PTR(-ENOMEM);
 	new_inode->i_fop = fops;
 	new_inode->i_private = data;
-	d_instantiate(dentry, new_inode);
-	fsnotify_create(parent_inode, dentry);
 
-out:
-	inode_unlock(parent_inode);
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry)) {
+		iput(new_inode);
+		return dentry;
+	}
+
+	d_make_persistent(dentry, new_inode);
+	fsnotify_create(parent->d_inode, dentry);
+	simple_done_creating(dentry);
 	return dentry;
 }
 
···
 					  const char *name)
 {
 	struct dentry *dentry;
-	struct inode *new_inode, *parent_inode;
-	struct super_block *sb;
+	struct inode *new_inode;
 
-	parent_inode = d_inode(parent);
-	inode_lock(parent_inode);
-
-	dentry = binderfs_create_dentry(parent, name);
-	if (IS_ERR(dentry))
-		goto out;
-
-	sb = parent_inode->i_sb;
-	new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
-	if (!new_inode) {
-		dput(dentry);
-		dentry = ERR_PTR(-ENOMEM);
-		goto out;
-	}
+	new_inode = binderfs_make_inode(parent->d_sb, S_IFDIR | 0755);
+	if (!new_inode)
+		return ERR_PTR(-ENOMEM);
 
 	new_inode->i_fop = &simple_dir_operations;
 	new_inode->i_op = &simple_dir_inode_operations;
 
-	set_nlink(new_inode, 2);
-	d_instantiate(dentry, new_inode);
-	inc_nlink(parent_inode);
-	fsnotify_mkdir(parent_inode, dentry);
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry)) {
+		iput(new_inode);
+		return dentry;
+	}
 
-out:
-	inode_unlock(parent_inode);
+	inc_nlink(parent->d_inode);
+	set_nlink(new_inode, 2);
+	d_make_persistent(dentry, new_inode);
+	fsnotify_mkdir(parent->d_inode, dentry);
+	simple_done_creating(dentry);
 	return dentry;
 }
 
···
 	 * During inode eviction struct binderfs_info is needed.
 	 * So first wipe the super_block then free struct binderfs_info.
 	 */
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 
 	if (info && info->ipc_ns)
 		put_ipc_ns(info->ipc_ns);

drivers/android/binderfs.c

···
 	}
 
 	root = sb->s_root;
-	inode_lock(d_inode(root));
-
-	/* look it up */
-	dentry = lookup_noperm(&QSTR(name), root);
+	dentry = simple_start_creating(root, name);
 	if (IS_ERR(dentry)) {
-		inode_unlock(d_inode(root));
 		ret = PTR_ERR(dentry);
 		goto err;
 	}
-
-	if (d_really_is_positive(dentry)) {
-		/* already exists */
-		dput(dentry);
-		inode_unlock(d_inode(root));
-		ret = -EEXIST;
-		goto err;
-	}
-
 	inode->i_private = device;
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	fsnotify_create(root->d_inode, dentry);
-	inode_unlock(d_inode(root));
+	simple_done_creating(dentry);
 
 	binder_add_device(device);
 
···
 	if (!device)
 		return -ENOMEM;
 
-	/* If we have already created a binder-control node, return. */
-	if (info->control_dentry) {
-		ret = 0;
-		goto out;
-	}
-
 	ret = -ENOMEM;
 	inode = new_inode(sb);
 	if (!inode)
···
 
 	inode->i_private = device;
 	info->control_dentry = dentry;
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
+	dput(dentry);
 
 	return 0;
 
···
 	return ret;
 }
 
-static struct dentry *binderfs_create_dentry(struct dentry *parent,
-					     const char *name)
-{
-	struct dentry *dentry;
-
-	dentry = lookup_noperm(&QSTR(name), parent);
-	if (IS_ERR(dentry))
-		return dentry;
-
-	/* Return error if the file/dir already exists. */
-	if (d_really_is_positive(dentry)) {
-		dput(dentry);
-		return ERR_PTR(-EEXIST);
-	}
-
-	return dentry;
-}
-
 struct dentry *binderfs_create_file(struct dentry *parent, const char *name,
 				    const struct file_operations *fops,
 				    void *data)
···
 	struct super_block *sb;
 
 	parent_inode = d_inode(parent);
-	inode_lock(parent_inode);
 
-	dentry = binderfs_create_dentry(parent, name);
+	dentry = simple_start_creating(parent, name);
 	if (IS_ERR(dentry))
-		goto out;
+		return dentry;
 
 	sb = parent_inode->i_sb;
 	new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
 	if (!new_inode) {
-		dput(dentry);
-		dentry = ERR_PTR(-ENOMEM);
-		goto out;
+		simple_done_creating(dentry);
+		return ERR_PTR(-ENOMEM);
 	}
 
 	new_inode->i_fop = fops;
 	new_inode->i_private = data;
-	d_instantiate(dentry, new_inode);
+	d_make_persistent(dentry, new_inode);
 	fsnotify_create(parent_inode, dentry);
-
-out:
-	inode_unlock(parent_inode);
-	return dentry;
+	simple_done_creating(dentry);
+	return dentry; // borrowed
 }
 
 static struct dentry *binderfs_create_dir(struct dentry *parent,
···
 	struct super_block *sb;
 
 	parent_inode = d_inode(parent);
-	inode_lock(parent_inode);
 
-	dentry = binderfs_create_dentry(parent, name);
+	dentry = simple_start_creating(parent, name);
 	if (IS_ERR(dentry))
-		goto out;
+		return dentry;
 
 	sb = parent_inode->i_sb;
 	new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
 	if (!new_inode) {
-		dput(dentry);
-		dentry = ERR_PTR(-ENOMEM);
-		goto out;
+		simple_done_creating(dentry);
+		return ERR_PTR(-ENOMEM);
 	}
 
 	new_inode->i_fop = &simple_dir_operations;
 	new_inode->i_op = &simple_dir_inode_operations;
 
 	set_nlink(new_inode, 2);
-	d_instantiate(dentry, new_inode);
+	d_make_persistent(dentry, new_inode);
 	inc_nlink(parent_inode);
 	fsnotify_mkdir(parent_inode, dentry);
-
-out:
-	inode_unlock(parent_inode);
+	simple_done_creating(dentry);
 	return dentry;
 }
 
···
 	 * During inode eviction struct binderfs_info is needed.
 	 * So first wipe the super_block then free struct binderfs_info.
 	 */
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 
 	if (info && info->ipc_ns)
 		put_ipc_ns(info->ipc_ns);

drivers/base/devtmpfs.c

···
 #else
 	.init_fs_context = ramfs_init_fs_context,
 #endif
-	.kill_sb = kill_litter_super,
+	.kill_sb = kill_anon_super,
 };
 
 /* Simply take a ref on the existing mount */

drivers/misc/ibmasm/ibmasmfs.c

···
 	.drop_inode	= inode_just_drop,
 };
 
-static const struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;
-
 static struct file_system_type ibmasmfs_type = {
 	.owner          = THIS_MODULE,
 	.name           = "ibmasmfs",
 	.init_fs_context = ibmasmfs_init_fs_context,
-	.kill_sb        = kill_litter_super,
+	.kill_sb        = kill_anon_super,
 };
 MODULE_ALIAS_FS("ibmasmfs");
 
···
 		return -ENOMEM;
 
 	root->i_op = &simple_dir_inode_operations;
-	root->i_fop = ibmasmfs_dir_ops;
+	root->i_fop = &simple_dir_operations;
 
 	sb->s_root = d_make_root(root);
 	if (!sb->s_root)
···
 	return ret;
 }
 
-static struct dentry *ibmasmfs_create_file(struct dentry *parent,
+static int ibmasmfs_create_file(struct dentry *parent,
 			const char *name,
 			const struct file_operations *fops,
 			void *data,
···
 
 	dentry = d_alloc_name(parent, name);
 	if (!dentry)
-		return NULL;
+		return -ENOMEM;
 
 	inode = ibmasmfs_make_inode(parent->d_sb, S_IFREG | mode);
 	if (!inode) {
 		dput(dentry);
-		return NULL;
+		return -ENOMEM;
 	}
 
 	inode->i_fop = fops;
 	inode->i_private = data;
 
-	d_add(dentry, inode);
-	return dentry;
+	d_make_persistent(dentry, inode);
+	dput(dentry);
+	return 0;
 }
 
 static struct dentry *ibmasmfs_create_dir(struct dentry *parent,
···
 	}
 
 	inode->i_op = &simple_dir_inode_operations;
-	inode->i_fop = ibmasmfs_dir_ops;
+	inode->i_fop = &simple_dir_operations;
 
-	d_add(dentry, inode);
-	return dentry;
+	d_make_persistent(dentry, inode);
+	dput(dentry);
+	return dentry; // borrowed
 }
 
 int ibmasmfs_register(void)

drivers/usb/gadget/function/f_fs.c

···
 	struct ffs_data			*ffs;
 	struct ffs_ep			*ep;	/* P: ffs->eps_lock */
 
-	struct dentry			*dentry;
-
 	/*
 	 * Buffer for holding data from partial reads which may happen since
 	 * we’re rounding user read requests to a multiple of a max packet size.
···
 };
 
 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
-static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
+static void ffs_epfiles_destroy(struct super_block *sb,
+				struct ffs_epfile *epfiles, unsigned count);
 
-static struct dentry *
-ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
-		   const struct file_operations *fops);
+static int ffs_sb_create_file(struct super_block *sb, const char *name,
+			      void *data, const struct file_operations *fops);
 
 /* Devices management *******************************************************/
 
···
 
 static int ffs_ep0_open(struct inode *inode, struct file *file)
 {
-	struct ffs_data *ffs = inode->i_private;
+	struct ffs_data *ffs = inode->i_sb->s_fs_info;
+	int ret;
 
-	if (ffs->state == FFS_CLOSING)
-		return -EBUSY;
+	/* Acquire mutex */
+	ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
+	if (ret < 0)
+		return ret;
 
-	file->private_data = ffs;
 	ffs_data_opened(ffs);
+	if (ffs->state == FFS_CLOSING) {
+		ffs_data_closed(ffs);
+		mutex_unlock(&ffs->mutex);
+		return -EBUSY;
+	}
+	mutex_unlock(&ffs->mutex);
+	file->private_data = ffs;
 
 	return stream_open(inode, file);
 }
···
 static int
 ffs_epfile_open(struct inode *inode, struct file *file)
 {
-	struct ffs_epfile *epfile = inode->i_private;
+	struct ffs_data *ffs = inode->i_sb->s_fs_info;
+	struct ffs_epfile *epfile;
+	int ret;
 
-	if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
+	/* Acquire mutex */
+	ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
+	if (ret < 0)
+		return ret;
+
+	if (!atomic_inc_not_zero(&ffs->opened)) {
+		mutex_unlock(&ffs->mutex);
 		return -ENODEV;
+	}
+	/*
+	 * we want the state to be FFS_ACTIVE; FFS_ACTIVE alone is
+	 * not enough, though - we might have been through FFS_CLOSING
+	 * and back to FFS_ACTIVE, with our file already removed.
+	 */
+	epfile = smp_load_acquire(&inode->i_private);
+	if (unlikely(ffs->state != FFS_ACTIVE || !epfile)) {
+		mutex_unlock(&ffs->mutex);
+		ffs_data_closed(ffs);
+		return -ENODEV;
+	}
+	mutex_unlock(&ffs->mutex);
 
 	file->private_data = epfile;
-	ffs_data_opened(epfile->ffs);
-
 	return stream_open(inode, file);
 }
 
···
 static int
 ffs_epfile_release(struct inode *inode, struct file *file)
 {
-	struct ffs_epfile *epfile = inode->i_private;
+	struct ffs_epfile *epfile = file->private_data;
 	struct ffs_dmabuf_priv *priv, *tmp;
 	struct ffs_data *ffs = epfile->ffs;
 
···
 }
 
 /* Create "regular" file */
-static struct dentry *ffs_sb_create_file(struct super_block *sb,
-					const char *name, void *data,
-					const struct file_operations *fops)
+static int ffs_sb_create_file(struct super_block *sb, const char *name,
+			      void *data, const struct file_operations *fops)
 {
 	struct ffs_data	*ffs = sb->s_fs_info;
 	struct dentry	*dentry;
 	struct inode	*inode;
 
-	dentry = d_alloc_name(sb->s_root, name);
-	if (!dentry)
-		return NULL;
-
 	inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
-	if (!inode) {
-		dput(dentry);
-		return NULL;
+	if (!inode)
+		return -ENOMEM;
+	dentry = simple_start_creating(sb->s_root, name);
+	if (IS_ERR(dentry)) {
+		iput(inode);
+		return PTR_ERR(dentry);
 	}
 
-	d_add(dentry, inode);
-	return dentry;
+	d_make_persistent(dentry, inode);
+
+	simple_done_creating(dentry);
+	return 0;
 }
 
 /* Super block */
···
 		return -ENOMEM;
 
 	/* EP0 file */
-	if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
-		return -ENOMEM;
-
-	return 0;
+	return ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations);
 }
 
 enum {
···
 	return 0;
 }
 
+static void ffs_data_reset(struct ffs_data *ffs);
+
 static void
 ffs_fs_kill_sb(struct super_block *sb)
 {
-	kill_litter_super(sb);
-	if (sb->s_fs_info)
-		ffs_data_closed(sb->s_fs_info);
+	kill_anon_super(sb);
+	if (sb->s_fs_info) {
+		struct ffs_data *ffs = sb->s_fs_info;
+		ffs->state = FFS_CLOSING;
+		ffs_data_reset(ffs);
+		// no configfs accesses from that point on,
+		// so no further schedule_work() is possible
+		cancel_work_sync(&ffs->reset_work);
+		ffs_data_put(ffs);
+	}
 }
 
 static struct file_system_type ffs_fs_type = {
···
 /* ffs_data and ffs_function construction and destruction code **************/
 
 static void ffs_data_clear(struct ffs_data *ffs);
-static void ffs_data_reset(struct ffs_data *ffs);
 
 static void ffs_data_get(struct ffs_data *ffs)
 {
···
 
 static void ffs_data_opened(struct ffs_data *ffs)
 {
-	refcount_inc(&ffs->ref);
 	if (atomic_add_return(1, &ffs->opened) == 1 &&
 			ffs->state == FFS_DEACTIVATED) {
 		ffs->state = FFS_CLOSING;
···
 
 static void ffs_data_closed(struct ffs_data *ffs)
 {
-	struct ffs_epfile *epfiles;
-	unsigned long flags;
-
 	if (atomic_dec_and_test(&ffs->opened)) {
 		if (ffs->no_disconnect) {
+			struct ffs_epfile *epfiles;
+			unsigned long flags;
+
 			ffs->state = FFS_DEACTIVATED;
 			spin_lock_irqsave(&ffs->eps_lock, flags);
 			epfiles = ffs->epfiles;
···
 							flags);
 
 			if (epfiles)
-				ffs_epfiles_destroy(epfiles,
+				ffs_epfiles_destroy(ffs->sb, epfiles,
 						 ffs->eps_count);
 
 			if (ffs->setup_state == FFS_SETUP_PENDING)
···
 			ffs_data_reset(ffs);
 		}
 	}
-	if (atomic_read(&ffs->opened) < 0) {
-		ffs->state = FFS_CLOSING;
-		ffs_data_reset(ffs);
-	}
-
-	ffs_data_put(ffs);
 }
 
 static struct ffs_data *ffs_data_new(const char *dev_name)
···
 	 * copy of epfile will save us from use-after-free.
 	 */
 	if (epfiles) {
-		ffs_epfiles_destroy(epfiles, ffs->eps_count);
+		ffs_epfiles_destroy(ffs->sb, epfiles, ffs->eps_count);
 		ffs->epfiles = NULL;
 	}
 
···
 {
 	struct ffs_epfile *epfile, *epfiles;
 	unsigned i, count;
+	int err;
 
 	count = ffs->eps_count;
 	epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
···
 			sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
 		else
 			sprintf(epfile->name, "ep%u", i);
-		epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
-						 epfile,
-						 &ffs_epfile_operations);
-		if (!epfile->dentry) {
-			ffs_epfiles_destroy(epfiles, i - 1);
-			return -ENOMEM;
+		err = ffs_sb_create_file(ffs->sb, epfile->name,
+					 epfile, &ffs_epfile_operations);
+		if (err) {
+			ffs_epfiles_destroy(ffs->sb, epfiles, i - 1);
+			return err;
 		}
 	}
 
···
 	return 0;
 }
 
-static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
+static void clear_one(struct dentry *dentry)
+{
+	smp_store_release(&dentry->d_inode->i_private, NULL);
+}
+
+static void ffs_epfiles_destroy(struct super_block *sb,
+				struct ffs_epfile *epfiles, unsigned count)
 {
 	struct ffs_epfile *epfile = epfiles;
+	struct dentry *root = sb->s_root;
 
 	for (; count; --count, ++epfile) {
 		BUG_ON(mutex_is_locked(&epfile->mutex));
-		if (epfile->dentry) {
-			simple_recursive_removal(epfile->dentry, NULL);
-			epfile->dentry = NULL;
-		}
+		simple_remove_by_name(root, epfile->name, clear_one);
 	}
 
 	kfree(epfiles);

drivers/usb/gadget/legacy/inode.c

···
 	void				*buf;
 	wait_queue_head_t		wait;
 	struct super_block		*sb;
-	struct dentry			*dentry;
 
 	/* except this scratch i/o buffer for ep0 */
 	u8				rbuf[RBUF_SIZE];
···
 	struct usb_endpoint_descriptor	desc, hs_desc;
 	struct list_head		epfiles;
 	wait_queue_head_t		wait;
-	struct dentry			*dentry;
 };
 
 static inline void get_ep (struct ep_data *data)
···
 	spin_lock_irq (&dev->lock);
 	while (!list_empty(&dev->epfiles)) {
 		struct ep_data	*ep;
-		struct dentry	*dentry;
 
 		/* break link to FS */
 		ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
 		list_del_init (&ep->epfiles);
 		spin_unlock_irq (&dev->lock);
-
-		dentry = ep->dentry;
-		ep->dentry = NULL;
 
 		/* break link to controller */
 		mutex_lock(&ep->lock);
···
 		mutex_unlock(&ep->lock);
 
 		wake_up (&ep->wait);
-		put_ep (ep);
 
 		/* break link to dcache */
-		simple_recursive_removal(dentry, NULL);
+		simple_remove_by_name(dev->sb->s_root, ep->name, NULL);
+
+		put_ep (ep);
 
 		spin_lock_irq (&dev->lock);
 	}
···
 }
 
 
-static struct dentry *
-gadgetfs_create_file (struct super_block *sb, char const *name,
+static int gadgetfs_create_file (struct super_block *sb, char const *name,
 		void *data, const struct file_operations *fops);
 
 static int activate_ep_files (struct dev_data *dev)
 {
 	struct usb_ep	*ep;
 	struct ep_data	*data;
+	int err;
 
 	gadget_for_each_ep (ep, dev->gadget) {
 
···
 		if (!data->req)
 			goto enomem1;
 
-		data->dentry = gadgetfs_create_file (dev->sb, data->name,
+		err = gadgetfs_create_file (dev->sb, data->name,
 				data, &ep_io_operations);
-		if (!data->dentry)
+		if (err)
 			goto enomem2;
 		list_add_tail (&data->epfiles, &dev->epfiles);
 	}
···
 /* creates in fs root directory, so non-renamable and non-linkable.
  * so inode and dentry are paired, until device reconfig.
  */
-static struct dentry *
-gadgetfs_create_file (struct super_block *sb, char const *name,
+static int gadgetfs_create_file (struct super_block *sb, char const *name,
 		void *data, const struct file_operations *fops)
 {
 	struct dentry	*dentry;
 	struct inode	*inode;
 
-	dentry = d_alloc_name(sb->s_root, name);
-	if (!dentry)
-		return NULL;
-
 	inode = gadgetfs_make_inode (sb, data, fops,
 			S_IFREG | (default_perm & S_IRWXUGO));
-	if (!inode) {
-		dput(dentry);
-		return NULL;
+	if (!inode)
+		return -ENOMEM;
+
+	dentry = simple_start_creating(sb->s_root, name);
+	if (IS_ERR(dentry)) {
+		iput(inode);
+		return PTR_ERR(dentry);
 	}
-	d_add (dentry, inode);
-	return dentry;
+
+	d_make_persistent(dentry, inode);
+
+	simple_done_creating(dentry);
+	return 0;
 }
 
 static const struct super_operations gadget_fs_operations = {
···
 		goto Enomem;
 
 	dev->sb = sb;
-	dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
-	if (!dev->dentry) {
+	rc = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
+	if (rc) {
 		put_dev(dev);
 		goto Enomem;
 	}
···
 gadgetfs_kill_sb (struct super_block *sb)
 {
 	mutex_lock(&sb_mutex);
-	kill_litter_super (sb);
+	kill_anon_super (sb);
 	if (the_device) {
 		put_dev (the_device);
 		the_device = NULL;

drivers/xen/xenfs/super.c

···
 	.owner =	THIS_MODULE,
 	.name =		"xenfs",
 	.init_fs_context = xenfs_init_fs_context,
-	.kill_sb =	kill_litter_super,
+	.kill_sb =	kill_anon_super,
 };
 MODULE_ALIAS_FS("xenfs");
 

fs/autofs/inode.c

···
 	}
 
 	pr_debug("shutting down\n");
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 	if (sbi)
 		kfree_rcu(sbi, rcu);
 }

fs/autofs/root.c

···
 	}
 	inode->i_private = cp;
 	inode->i_size = size;
-	d_add(dentry, inode);
 
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count++;
 
···
 static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
-	struct autofs_info *ino = autofs_dentry_ino(dentry);
 	struct autofs_info *p_ino;
 
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count--;
-	dput(ino->dentry);
+	d_make_discardable(dentry);
 
 	d_inode(dentry)->i_size = 0;
 	clear_nlink(d_inode(dentry));
···
 
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count--;
-	dput(ino->dentry);
+	d_make_discardable(dentry);
 	d_inode(dentry)->i_size = 0;
 	clear_nlink(d_inode(dentry));
 
···
 	inode = autofs_get_inode(dir->i_sb, S_IFDIR | mode);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
-	d_add(dentry, inode);
 
 	if (sbi->version < 5)
 		autofs_set_leaf_automount_flags(dentry);
 
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count++;
 	inc_nlink(dir);

fs/binfmt_misc.c

···
 
 /* /register */
 
+/* add to filesystem */
+static int add_entry(Node *e, struct super_block *sb)
+{
+	struct dentry *dentry = simple_start_creating(sb->s_root, e->name);
+	struct inode *inode;
+	struct binfmt_misc *misc;
+
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	inode = bm_get_inode(sb, S_IFREG | 0644);
+	if (unlikely(!inode)) {
+		simple_done_creating(dentry);
+		return -ENOMEM;
+	}
+
+	refcount_set(&e->users, 1);
+	e->dentry = dentry;
+	inode->i_private = e;
+	inode->i_fop = &bm_entry_operations;
+
+	d_make_persistent(dentry, inode);
+	misc = i_binfmt_misc(inode);
+	write_lock(&misc->entries_lock);
+	list_add(&e->list, &misc->entries);
+	write_unlock(&misc->entries_lock);
+	simple_done_creating(dentry);
+	return 0;
+}
+
 static ssize_t bm_register_write(struct file *file, const char __user *buffer,
 			       size_t count, loff_t *ppos)
 {
 	Node *e;
-	struct inode *inode;
 	struct super_block *sb = file_inode(file)->i_sb;
-	struct dentry *root = sb->s_root, *dentry;
-	struct binfmt_misc *misc;
 	int err = 0;
 	struct file *f = NULL;
 
···
 		e->interp_file = f;
 	}
 
-	inode_lock(d_inode(root));
-	dentry = lookup_noperm(&QSTR(e->name), root);
-	err = PTR_ERR(dentry);
-	if (IS_ERR(dentry))
-		goto out;
-
-	err = -EEXIST;
-	if (d_really_is_positive(dentry))
-		goto out2;
-
-	inode = bm_get_inode(sb, S_IFREG | 0644);
-
-	err = -ENOMEM;
-	if (!inode)
-		goto out2;
-
-	refcount_set(&e->users, 1);
-	e->dentry = dget(dentry);
-	inode->i_private = e;
-	inode->i_fop = &bm_entry_operations;
-
-	d_instantiate(dentry, inode);
-	misc = i_binfmt_misc(inode);
-	write_lock(&misc->entries_lock);
-	list_add(&e->list, &misc->entries);
-	write_unlock(&misc->entries_lock);
-
-	err = 0;
-out2:
-	dput(dentry);
-out:
-	inode_unlock(d_inode(root));
-
+	err = add_entry(e, sb);
 	if (err) {
 		if (f) {
 			exe_file_allow_write_access(f);
···
 	.name		= "binfmt_misc",
 	.init_fs_context = bm_init_fs_context,
 	.fs_flags	= FS_USERNS_MOUNT,
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= kill_anon_super,
 };
 MODULE_ALIAS_FS("binfmt_misc");
 

fs/configfs/dir.c

···
 
 	configfs_remove_dirent(d);
 
-	if (d_really_is_positive(d))
-		simple_rmdir(d_inode(parent),d);
+	if (d_really_is_positive(d)) {
+		if (likely(simple_empty(d))) {
+			__simple_rmdir(d_inode(parent),d);
+			dput(d);
+		} else {
+			pr_warn("remove_dir (%pd): attributes remain", d);
+		}
+	}
 
 	pr_debug(" o %pd removing done (%d)\n", d, d_count(d));
 

fs/configfs/inode.c

···
 			dget_dlock(dentry);
 			__d_drop(dentry);
 			spin_unlock(&dentry->d_lock);
-			simple_unlink(d_inode(parent), dentry);
+			__simple_unlink(d_inode(parent), dentry);
+			dput(dentry);
 		} else
 			spin_unlock(&dentry->d_lock);
 	}

fs/configfs/mount.c

···
 	.owner		= THIS_MODULE,
 	.name		= "configfs",
 	.init_fs_context = configfs_init_fs_context,
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= kill_anon_super,
 };
 MODULE_ALIAS_FS("configfs");
 

fs/dcache.c

···
 	return false;
 }
 
+static void finish_dput(struct dentry *dentry)
+	__releases(dentry->d_lock)
+	__releases(RCU)
+{
+	while (lock_for_kill(dentry)) {
+		rcu_read_unlock();
+		dentry = __dentry_kill(dentry);
+		if (!dentry)
+			return;
+		if (retain_dentry(dentry, true)) {
+			spin_unlock(&dentry->d_lock);
+			return;
+		}
+		rcu_read_lock();
+	}
+	rcu_read_unlock();
+	spin_unlock(&dentry->d_lock);
+}
 
 /* 
  * This is dput
···
 		rcu_read_unlock();
 		return;
 	}
-	while (lock_for_kill(dentry)) {
-		rcu_read_unlock();
-		dentry = __dentry_kill(dentry);
-		if (!dentry)
-			return;
-		if (retain_dentry(dentry, true)) {
-			spin_unlock(&dentry->d_lock);
-			return;
-		}
-		rcu_read_lock();
-	}
-	rcu_read_unlock();
-	spin_unlock(&dentry->d_lock);
+	finish_dput(dentry);
 }
 EXPORT_SYMBOL(dput);
+
+void d_make_discardable(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	WARN_ON(!(dentry->d_flags & DCACHE_PERSISTENT));
+	dentry->d_flags &= ~DCACHE_PERSISTENT;
+	dentry->d_lockref.count--;
+	rcu_read_lock();
+	finish_dput(dentry);
+}
+EXPORT_SYMBOL(d_make_discardable);
 
 static void to_shrink_list(struct dentry *dentry, struct list_head *list)
 __must_hold(&dentry->d_lock)
···
 	return ret;
 }
 
+static enum d_walk_ret select_collect_umount(void *_data, struct dentry *dentry)
+{
+	if (dentry->d_flags & DCACHE_PERSISTENT) {
+		dentry->d_flags &= ~DCACHE_PERSISTENT;
+		dentry->d_lockref.count--;
+	}
+	return select_collect(_data, dentry);
+}
+
 static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)
 {
 	struct select_data *data = _data;
···
 }
 
 /**
- * shrink_dcache_parent - prune dcache
+ * shrink_dcache_tree - prune dcache
  * @parent: parent of entries to prune
+ * @for_umount: true if we want to unpin the persistent ones
  *
  * Prune the dcache to remove unused children of the parent dentry.
  */
-void shrink_dcache_parent(struct dentry *parent)
+static void shrink_dcache_tree(struct dentry *parent, bool for_umount)
 {
 	for (;;) {
 		struct select_data data = {.start = parent};
 
 		INIT_LIST_HEAD(&data.dispose);
-		d_walk(parent, &data, select_collect);
+		d_walk(parent, &data,
+			for_umount ? select_collect_umount : select_collect);
 
 		if (!list_empty(&data.dispose)) {
 			shrink_dentry_list(&data.dispose);
···
 		if (!list_empty(&data.dispose))
 			shrink_dentry_list(&data.dispose);
 	}
+}
+
+void shrink_dcache_parent(struct dentry *parent)
+{
+	shrink_dcache_tree(parent, false);
 }
 EXPORT_SYMBOL(shrink_dcache_parent);
 
···
 
 static void do_one_tree(struct dentry *dentry)
 {
-	shrink_dcache_parent(dentry);
+	shrink_dcache_tree(dentry, true);
 	d_walk(dentry, dentry, umount_check);
 	d_drop(dentry);
 	dput(dentry);
···
 	unsigned add_flags = d_flags_for_inode(inode);
 	WARN_ON(d_in_lookup(dentry));
 
-	spin_lock(&dentry->d_lock);
 	/*
 	 * The negative counter only tracks dentries on the LRU. Don't dec if
 	 * d_lru is on another list.
···
 	__d_set_inode_and_type(dentry, inode, add_flags);
 	raw_write_seqcount_end(&dentry->d_seq);
 	fsnotify_update_flags(dentry);
-	spin_unlock(&dentry->d_lock);
 }
 
 /**
···
 	if (inode) {
 		security_d_instantiate(entry, inode);
 		spin_lock(&inode->i_lock);
+		spin_lock(&entry->d_lock);
 		__d_instantiate(entry, inode);
+		spin_unlock(&entry->d_lock);
 		spin_unlock(&inode->i_lock);
 	}
 }
···
 	lockdep_annotate_inode_mutex_key(inode);
 	security_d_instantiate(entry, inode);
 	spin_lock(&inode->i_lock);
+	spin_lock(&entry->d_lock);
 	__d_instantiate(entry, inode);
+	spin_unlock(&entry->d_lock);
 	WARN_ON(!(inode_state_read(inode) & I_NEW));
 	inode_state_clear(inode, I_NEW | I_CREATING);
 	inode_wake_up_bit(inode, __I_NEW);
···
 }
 EXPORT_SYMBOL(d_add);
 
+struct dentry *d_make_persistent(struct dentry *dentry, struct inode *inode)
+{
+	WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
+	WARN_ON(!inode);
+	security_d_instantiate(dentry, inode);
+	spin_lock(&inode->i_lock);
+	spin_lock(&dentry->d_lock);
+	__d_instantiate(dentry, inode);
+	dentry->d_flags |= DCACHE_PERSISTENT;
+	dget_dlock(dentry);
+	if (d_unhashed(dentry))
+		__d_rehash(dentry);
+	spin_unlock(&dentry->d_lock);
+	spin_unlock(&inode->i_lock);
+	return dentry;
+}
+EXPORT_SYMBOL(d_make_persistent);
+
 static void swap_names(struct dentry *dentry, struct dentry *target)
 {
 	if (unlikely(dname_external(target))) {
···
 	return subdir;
 }
 EXPORT_SYMBOL(is_subdir);
-
-static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
-{
-	struct dentry *root = data;
-	if (dentry != root) {
-		if (d_unhashed(dentry) || !dentry->d_inode)
-			return D_WALK_SKIP;
-
-		if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
-			dentry->d_flags |= DCACHE_GENOCIDE;
-			dentry->d_lockref.count--;
-		}
-	}
-	return D_WALK_CONTINUE;
-}
-
-void d_genocide(struct dentry *parent)
-{
-	d_walk(parent, parent, d_genocide_kill);
-}
 
 void d_mark_tmpfile(struct file *file, struct inode *inode)
 {

fs/debugfs/inode.c

···
 	.name =		"debugfs",
 	.init_fs_context = debugfs_init_fs_context,
 	.parameters =	debugfs_param_specs,
-	.kill_sb =	kill_litter_super,
+	.kill_sb =	kill_anon_super,
 };
 MODULE_ALIAS_FS("debugfs");
 
···
 
 static struct dentry *debugfs_failed_creating(struct dentry *dentry)
 {
-	inode_unlock(d_inode(dentry->d_parent));
-	dput(dentry);
+	simple_done_creating(dentry);
 	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 	return ERR_PTR(-ENOMEM);
 }
 
 static struct dentry *debugfs_end_creating(struct dentry *dentry)
 {
-	inode_unlock(d_inode(dentry->d_parent));
-	return dentry;
+	simple_done_creating(dentry);
+	return dentry; // borrowed
 }
 
 static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
···
 	if (IS_ERR(dentry))
 		return dentry;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
-		debugfs_failed_creating(dentry);
-		return ERR_PTR(-EPERM);
-	}
-
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create file '%s'\n",
···
 	DEBUGFS_I(inode)->raw = real_fops;
 	DEBUGFS_I(inode)->aux = (void *)aux;
 
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	fsnotify_create(d_inode(dentry->d_parent), dentry);
 	return debugfs_end_creating(dentry);
 }
···
 	if (IS_ERR(dentry))
 		return dentry;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
-		debugfs_failed_creating(dentry);
-		return ERR_PTR(-EPERM);
-	}
-
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create directory '%s'\n",
···
 
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	inc_nlink(d_inode(dentry->d_parent));
 	fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
 	return debugfs_end_creating(dentry);
···
 	if (IS_ERR(dentry))
 		return dentry;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
-		debugfs_failed_creating(dentry);
-		return ERR_PTR(-EPERM);
-	}
-
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create automount '%s'\n",
···
 	DEBUGFS_I(inode)->automount = f;
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	inc_nlink(d_inode(dentry->d_parent));
 	fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
 	return debugfs_end_creating(dentry);
···
 	inode->i_mode = S_IFLNK | S_IRWXUGO;
 	inode->i_op = &debugfs_symlink_inode_operations;
 	inode->i_link = link;
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	return debugfs_end_creating(dentry);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_symlink);

fs/devpts/inode.c

···
 	struct ida allocated_ptys;
 	struct pts_mount_opts mount_opts;
 	struct super_block *sb;
-	struct dentry *ptmx_dentry;
+	struct inode *ptmx_inode; // borrowed
 };
 
 static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)
···
 static int mknod_ptmx(struct super_block *sb, struct fs_context *fc)
 {
 	int mode;
-	int rc = -ENOMEM;
 	struct dentry *dentry;
 	struct inode *inode;
 	struct dentry *root = sb->s_root;
···
 	kuid_t ptmx_uid = current_fsuid();
 	kgid_t ptmx_gid = current_fsgid();
 
-	inode_lock(d_inode(root));
-
-	/* If we have already created ptmx node, return */
-	if (fsi->ptmx_dentry) {
-		rc = 0;
-		goto out;
-	}
-
-	dentry = d_alloc_name(root, "ptmx");
-	if (!dentry) {
+	dentry = simple_start_creating(root, "ptmx");
+	if (IS_ERR(dentry)) {
 		pr_err("Unable to alloc dentry for ptmx node\n");
-		goto out;
+		return PTR_ERR(dentry);
 	}
 
 	/*
···
 	 */
 	inode = new_inode(sb);
 	if (!inode) {
+		simple_done_creating(dentry);
 		pr_err("Unable to alloc inode for ptmx node\n");
-		dput(dentry);
-		goto out;
+		return -ENOMEM;
 	}
 
 	inode->i_ino = 2;
···
 	init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2));
 	inode->i_uid = ptmx_uid;
 	inode->i_gid = ptmx_gid;
+	fsi->ptmx_inode = inode;
 
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
 
-	fsi->ptmx_dentry = dentry;
-	rc = 0;
-out:
-	inode_unlock(d_inode(root));
-	return rc;
+	simple_done_creating(dentry);
+
+	return 0;
 }
 
 static void update_ptmx_mode(struct pts_fs_info *fsi)
 {
-	struct inode *inode;
-	if (fsi->ptmx_dentry) {
-		inode = d_inode(fsi->ptmx_dentry);
-		inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode;
-	}
+	fsi->ptmx_inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode;
 }
 
 static int devpts_reconfigure(struct fs_context *fc)
···
 	if (fsi)
 		ida_destroy(&fsi->allocated_ptys);
 	kfree(fsi);
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 }
 
 static struct file_system_type devpts_fs_type = {
···
 	sprintf(s, "%d", index);
 
 	dentry = d_alloc_name(root, s);
-	if (dentry) {
-		dentry->d_fsdata = priv;
-		d_add(dentry, inode);
-		fsnotify_create(d_inode(root), dentry);
-	} else {
+	if (!dentry) {
 		iput(inode);
-		dentry = ERR_PTR(-ENOMEM);
+		return ERR_PTR(-ENOMEM);
 	}
-
-	return dentry;
+	dentry->d_fsdata = priv;
+	d_make_persistent(dentry, inode);
+	fsnotify_create(d_inode(root), dentry);
+	dput(dentry);
+	return dentry; // borrowed
 }
 
 /**
···
 	drop_nlink(dentry->d_inode);
 	d_drop(dentry);
 	fsnotify_unlink(d_inode(dentry->d_parent), dentry);
-	dput(dentry);	/* d_alloc_name() in devpts_pty_new() */
+	d_make_discardable(dentry);
 }
 
 static int __init init_devpts_fs(void)

fs/efivarfs/inode.c

···
 
 	inode->i_private = var;
 
-	d_instantiate(dentry, inode);
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 
 	return 0;
 }
···
 	if (efivar_entry_delete(var))
 		return -EINVAL;
 
-	drop_nlink(d_inode(dentry));
-	dput(dentry);
-	return 0;
+	return simple_unlink(dir, dentry);
 };
 
 const struct inode_operations efivarfs_dir_inode_operations = {

fs/efivarfs/super.c

···
 	inode->i_private = entry;
 	i_size_write(inode, size + sizeof(__u32)); /* attributes + data */
 	inode_unlock(inode);
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
+	dput(dentry);
 
 	return 0;
 
···
 	struct efivarfs_fs_info *sfi = sb->s_fs_info;
 
 	blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 
 	kfree(sfi);
 }

fs/fuse/control.c

···
 
 static struct dentry *fuse_ctl_add_dentry(struct dentry *parent,
 					  struct fuse_conn *fc,
-					  const char *name,
-					  int mode, int nlink,
+					  const char *name, int mode,
 					  const struct inode_operations *iop,
 					  const struct file_operations *fop)
 {
···
 	if (iop)
 		inode->i_op = iop;
 	inode->i_fop = fop;
-	set_nlink(inode, nlink);
+	if (S_ISDIR(mode)) {
+		inc_nlink(d_inode(parent));
+		inc_nlink(inode);
+	}
 	inode->i_private = fc;
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
+	dput(dentry);
 
+	/*
+	 * We are returning a borrowed reference here - it's only good while
+	 * fuse_mutex is held.  Actually it's d_make_persistent() return
+	 * value...
+	 */
 	return dentry;
 }
 
···
 		return 0;
 
 	parent = fuse_control_sb->s_root;
-	inc_nlink(d_inode(parent));
 	sprintf(name, "%u", fc->dev);
-	parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR | 0500, 2,
+	parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR | 0500,
 				     &simple_dir_inode_operations,
 				     &simple_dir_operations);
 	if (!parent)
 		goto err;
 
-	if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400, 1,
+	if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400,
 				 NULL, &fuse_ctl_waiting_ops) ||
-	    !fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG | 0200, 1,
+	    !fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG | 0200,
 				 NULL, &fuse_ctl_abort_ops) ||
 	    !fuse_ctl_add_dentry(parent, fc, "max_background", S_IFREG | 0600,
-				 1, NULL, &fuse_conn_max_background_ops) ||
+				 NULL, &fuse_conn_max_background_ops) ||
 	    !fuse_ctl_add_dentry(parent, fc, "congestion_threshold",
-				 S_IFREG | 0600, 1, NULL,
+				 S_IFREG | 0600, NULL,
 				 &fuse_conn_congestion_threshold_ops))
 		goto err;
 
···
  */
 void fuse_ctl_remove_conn(struct fuse_conn *fc)
 {
-	struct dentry *dentry;
 	char name[32];
 
 	if (!fuse_control_sb || fc->no_control)
 		return;
 
 	sprintf(name, "%u", fc->dev);
-	dentry = lookup_noperm_positive_unlocked(&QSTR(name), fuse_control_sb->s_root);
-	if (!IS_ERR(dentry)) {
-		simple_recursive_removal(dentry, remove_one);
-		dput(dentry);	// paired with lookup_noperm_positive_unlocked()
-	}
+	simple_remove_by_name(fuse_control_sb->s_root, name, remove_one);
 }
 
 static int fuse_ctl_fill_super(struct super_block *sb, struct fs_context *fsc)
···
 	fuse_control_sb = NULL;
 	mutex_unlock(&fuse_mutex);
 
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 }
 
 static struct file_system_type fuse_ctl_fs_type = {

fs/hugetlbfs/inode.c

···
 	if (!inode)
 		return -ENOSPC;
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
-	d_instantiate(dentry, inode);
-	dget(dentry);/* Extra count - pin the dentry in core */
+	d_make_persistent(dentry, inode);
 	return 0;
 }
 
···
 	if (inode) {
 		int l = strlen(symname)+1;
 		error = page_symlink(inode, symname, l);
-		if (!error) {
-			d_instantiate(dentry, inode);
-			dget(dentry);
-		} else
+		if (!error)
+			d_make_persistent(dentry, inode);
+		else
 			iput(inode);
 	}
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
···
 	.name			= "hugetlbfs",
 	.init_fs_context	= hugetlbfs_init_fs_context,
 	.parameters		= hugetlb_fs_parameters,
-	.kill_sb		= kill_litter_super,
+	.kill_sb		= kill_anon_super,
 	.fs_flags               = FS_ALLOW_IDMAP,
 };
 

fs/internal.h

···
 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
 				const struct qstr *name, unsigned *seq);
-extern void d_genocide(struct dentry *);
 
 /*
  * pipe.c

fs/libfs.c

···
 				if (callback)
 					callback(victim);
 				fsnotify_delete(inode, d_inode(victim), victim);
-				dput(victim);		// unpin it
+				d_make_discardable(victim);
 			}
 			if (victim == dentry) {
 				inode_set_mtime_to_ts(inode,
···
 	return __simple_recursive_removal(dentry, callback, false);
 }
 EXPORT_SYMBOL(simple_recursive_removal);
+
+void simple_remove_by_name(struct dentry *parent, const char *name,
+                           void (*callback)(struct dentry *))
+{
+	struct dentry *dentry;
+
+	dentry = lookup_noperm_positive_unlocked(&QSTR(name), parent);
+	if (!IS_ERR(dentry)) {
+		simple_recursive_removal(dentry, callback);
+		dput(dentry);	// paired with lookup_noperm_positive_unlocked()
+	}
+}
+EXPORT_SYMBOL(simple_remove_by_name);
 
 /* caller holds parent directory with I_MUTEX_PARENT */
 void locked_recursive_removal(struct dentry *dentry,
···
 			      inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));
 	inc_nlink(inode);
 	ihold(inode);
-	dget(dentry);
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	return 0;
 }
 EXPORT_SYMBOL(simple_link);
···
 }
 EXPORT_SYMBOL(simple_empty);
 
-int simple_unlink(struct inode *dir, struct dentry *dentry)
+void __simple_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *inode = d_inode(dentry);
 
 	inode_set_mtime_to_ts(dir,
 			      inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));
 	drop_nlink(inode);
-	dput(dentry);
+}
+EXPORT_SYMBOL(__simple_unlink);
+
+void __simple_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	drop_nlink(d_inode(dentry));
+	__simple_unlink(dir, dentry);
+	drop_nlink(dir);
+}
+EXPORT_SYMBOL(__simple_rmdir);
+
+int simple_unlink(struct inode *dir, struct dentry *dentry)
+{
+	__simple_unlink(dir, dentry);
+	d_make_discardable(dentry);
 	return 0;
 }
 EXPORT_SYMBOL(simple_unlink);
···
 	if (!simple_empty(dentry))
 		return -ENOTEMPTY;
 
-	drop_nlink(d_inode(dentry));
-	simple_unlink(dir, dentry);
-	drop_nlink(dir);
+	__simple_rmdir(dir, dentry);
+	d_make_discardable(dentry);
 	return 0;
 }
 EXPORT_SYMBOL(simple_rmdir);
···
 		simple_inode_init_ts(inode);
 		inode->i_fop = files->ops;
 		inode->i_ino = i;
-		d_add(dentry, inode);
+		d_make_persistent(dentry, inode);
+		dput(dentry);
 	}
 	return 0;
 }
···
 	return start_dirop(parent, &qname, LOOKUP_CREATE | LOOKUP_EXCL);
 }
 EXPORT_SYMBOL(simple_start_creating);
+
+/* parent must have been held exclusive since simple_start_creating() */
+void simple_done_creating(struct dentry *child)
+{
+	inode_unlock(child->d_parent->d_inode);
+	dput(child);
+}
+EXPORT_SYMBOL(simple_done_creating);

fs/nfsd/nfsctl.c

···
 		inode->i_private = ncl;
 		kref_get(&ncl->cl_ref);
 	}
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	inc_nlink(dir);
 	fsnotify_mkdir(dir, dentry);
-	inode_unlock(dir);
-	return dentry;
+	simple_done_creating(dentry);
+	return dentry;	// borrowed
 }
 
 #if IS_ENABLED(CONFIG_SUNRPC_GSS)
···
 	inode->i_link = (char *)content;
 	inode->i_size = strlen(content);
 
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	fsnotify_create(dir, dentry);
-	inode_unlock(dir);
+	simple_done_creating(dentry);
 }
 #else
 static inline void _nfsd_symlink(struct dentry *parent, const char *name,
···
 		kref_get(&ncl->cl_ref);
 		inode->i_fop = files->ops;
 		inode->i_private = ncl;
-		d_instantiate(dentry, inode);
+		d_make_persistent(dentry, inode);
 		fsnotify_create(dir, dentry);
 		if (fdentries)
-			fdentries[i] = dentry;
-		inode_unlock(dir);
+			fdentries[i] = dentry; // borrowed
+		simple_done_creating(dentry);
 	}
 	return 0;
 }
···
 
 	nfsd_shutdown_threads(net);
 
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 	put_net(net);
 }
 

fs/ocfs2/dlmfs/dlmfs.c

···
 	ip->ip_conn = conn;
 
 	inc_nlink(dir);
-	d_instantiate(dentry, inode);
-	dget(dentry);	/* Extra count - pin the dentry in core */
+	d_make_persistent(dentry, inode);
 
 	status = 0;
 bail:
···
 		goto bail;
 	}
 
-	d_instantiate(dentry, inode);
-	dget(dentry);	/* Extra count - pin the dentry in core */
+	d_make_persistent(dentry, inode);
 bail:
 	return status;
 }
···
 static struct file_system_type dlmfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "ocfs2_dlmfs",
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= kill_anon_super,
 	.init_fs_context = dlmfs_init_fs_context,
 };
 MODULE_ALIAS_FS("ocfs2_dlmfs");

fs/proc/base.c

···
 		return 0;
 
 	if (pos == TGID_OFFSET - 2) {
-		struct inode *inode = d_inode(fs_info->proc_self);
-		if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
+		if (!dir_emit(ctx, "self", 4, self_inum, DT_LNK))
 			return 0;
 		ctx->pos = pos = pos + 1;
 	}
 	if (pos == TGID_OFFSET - 1) {
-		struct inode *inode = d_inode(fs_info->proc_thread_self);
-		if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
+		if (!dir_emit(ctx, "thread-self", 11, thread_self_inum, DT_LNK))
 			return 0;
 		ctx->pos = pos = pos + 1;
 	}

fs/proc/internal.h

···
 extern struct proc_dir_entry proc_root;
 
 extern void proc_self_init(void);
+extern unsigned self_inum, thread_self_inum;
 
 /*
  * task_[no]mmu.c

fs/proc/root.c

···
 {
 	struct proc_fs_info *fs_info = proc_sb_info(sb);
 
-	if (!fs_info) {
-		kill_anon_super(sb);
-		return;
-	}
-
-	dput(fs_info->proc_self);
-	dput(fs_info->proc_thread_self);
-
 	kill_anon_super(sb);
-	put_pid_ns(fs_info->pid_ns);
-	kfree_rcu(fs_info, rcu);
+	if (fs_info) {
+		put_pid_ns(fs_info->pid_ns);
+		kfree_rcu(fs_info, rcu);
+	}
 }
 
 static struct file_system_type proc_fs_type = {

fs/proc/self.c

···
 	.get_link	= proc_self_get_link,
 };
 
-static unsigned self_inum __ro_after_init;
+unsigned self_inum __ro_after_init;
 
 int proc_setup_self(struct super_block *s)
 {
 	struct inode *root_inode = d_inode(s->s_root);
-	struct proc_fs_info *fs_info = proc_sb_info(s);
 	struct dentry *self;
 	int ret = -ENOMEM;
 
···
 			inode->i_uid = GLOBAL_ROOT_UID;
 			inode->i_gid = GLOBAL_ROOT_GID;
 			inode->i_op = &proc_self_inode_operations;
-			d_add(self, inode);
+			d_make_persistent(self, inode);
 			ret = 0;
-		} else {
-			dput(self);
 		}
+		dput(self);
 	}
 	inode_unlock(root_inode);
 
 	if (ret)
 		pr_err("proc_fill_super: can't allocate /proc/self\n");
-	else
-		fs_info->proc_self = self;
 
 	return ret;
 }

fs/proc/thread_self.c

···
 	.get_link	= proc_thread_self_get_link,
 };
 
-static unsigned thread_self_inum __ro_after_init;
+unsigned thread_self_inum __ro_after_init;
 
 int proc_setup_thread_self(struct super_block *s)
 {
 	struct inode *root_inode = d_inode(s->s_root);
-	struct proc_fs_info *fs_info = proc_sb_info(s);
 	struct dentry *thread_self;
 	int ret = -ENOMEM;
 
···
 			inode->i_uid = GLOBAL_ROOT_UID;
 			inode->i_gid = GLOBAL_ROOT_GID;
 			inode->i_op = &proc_thread_self_inode_operations;
-			d_add(thread_self, inode);
+			d_make_persistent(thread_self, inode);
 			ret = 0;
-		} else {
-			dput(thread_self);
 		}
+		dput(thread_self);
 	}
 	inode_unlock(root_inode);
 
 	if (ret)
 		pr_err("proc_fill_super: can't allocate /proc/thread-self\n");
-	else
-		fs_info->proc_thread_self = thread_self;
-
 	return ret;
 }
 

fs/pstore/inode.c

···
 	if (!dentry)
 		return -ENOMEM;
 
-	private->dentry = dentry;
+	private->dentry = dentry; // borrowed
 	private->record = record;
 	inode->i_size = private->total_size = size;
 	inode->i_private = private;
···
 		inode_set_mtime_to_ts(inode,
 				      inode_set_ctime_to_ts(inode, record->time));
 
-	d_add(dentry, no_free_ptr(inode));
+	d_make_persistent(dentry, no_free_ptr(inode));
+	dput(dentry);
 
 	list_add(&(no_free_ptr(private))->list, &records_list);
 
···
 	guard(mutex)(&pstore_sb_lock);
 	WARN_ON(pstore_sb && pstore_sb != sb);
 
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 	pstore_sb = NULL;
 
 	guard(mutex)(&records_list_lock);

fs/ramfs/inode.c

···
 			goto out;
 		}
 
-		d_instantiate(dentry, inode);
-		dget(dentry);	/* Extra count - pin the dentry in core */
+		d_make_persistent(dentry, inode);
 		error = 0;
 		inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 	}
···
 
 		error = page_symlink(inode, symname, l);
 		if (!error) {
-			d_instantiate(dentry, inode);
-			dget(dentry);
+			d_make_persistent(dentry, inode);
 			inode_set_mtime_to_ts(dir,
 					      inode_set_ctime_current(dir));
 		} else
···
 void ramfs_kill_sb(struct super_block *sb)
 {
 	kfree(sb->s_fs_info);
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 }
 
 static struct file_system_type ramfs_fs_type = {

fs/super.c

···
 }
 EXPORT_SYMBOL(kill_anon_super);
 
-void kill_litter_super(struct super_block *sb)
-{
-	if (sb->s_root)
-		d_genocide(sb->s_root);
-	kill_anon_super(sb);
-}
-EXPORT_SYMBOL(kill_litter_super);
-
 int set_anon_super_fc(struct super_block *sb, struct fs_context *fc)
 {
 	return set_anon_super(sb, NULL);

fs/tracefs/event_inode.c

···
 						const struct eventfs_entry *entries,
 						int size, void *data)
 {
-	struct dentry *dentry = tracefs_start_creating(name, parent);
+	struct dentry *dentry;
 	struct eventfs_root_inode *rei;
 	struct eventfs_inode *ei;
 	struct tracefs_inode *ti;
···
 	if (security_locked_down(LOCKDOWN_TRACEFS))
 		return NULL;
 
+	dentry = tracefs_start_creating(name, parent);
 	if (IS_ERR(dentry))
 		return ERR_CAST(dentry);
 
···
 	 * something not worth much. Keeping directory links at 1
 	 * tells userspace not to trust the link number.
 	 */
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	/* The dentry of the "events" parent does keep track though */
 	inc_nlink(dentry->d_parent->d_inode);
 	fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
···
 	 * and destroyed dynamically.
 	 */
 	d_invalidate(dentry);
-	dput(dentry);
+	d_make_discardable(dentry);
 }

fs/tracefs/inode.c

···
 	.name =		"tracefs",
 	.init_fs_context = tracefs_init_fs_context,
 	.parameters	= tracefs_param_specs,
-	.kill_sb =	kill_litter_super,
+	.kill_sb =	kill_anon_super,
 };
 MODULE_ALIAS_FS("tracefs");
 
···
 
 struct dentry *tracefs_failed_creating(struct dentry *dentry)
 {
-	inode_unlock(d_inode(dentry->d_parent));
-	dput(dentry);
+	simple_done_creating(dentry);
 	simple_release_fs(&tracefs_mount, &tracefs_mount_count);
 	return NULL;
 }
 
 struct dentry *tracefs_end_creating(struct dentry *dentry)
 {
-	inode_unlock(d_inode(dentry->d_parent));
-	return dentry;
+	simple_done_creating(dentry);
+	return dentry;	// borrowed
 }
 
 /* Find the inode that this will use for default */
···
 	inode->i_private = data;
 	inode->i_uid = d_inode(dentry->d_parent)->i_uid;
 	inode->i_gid = d_inode(dentry->d_parent)->i_gid;
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	fsnotify_create(d_inode(dentry->d_parent), dentry);
 	return tracefs_end_creating(dentry);
 }
···
 
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	inc_nlink(d_inode(dentry->d_parent));
 	fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
 	return tracefs_end_creating(dentry);

include/linux/dcache.h

···
 	DCACHE_REFERENCED		= BIT(6),	/* Recently used, don't discard. */
 	DCACHE_DONTCACHE		= BIT(7),	/* Purge from memory on final dput() */
 	DCACHE_CANT_MOUNT		= BIT(8),
-	DCACHE_GENOCIDE			= BIT(9),
 	DCACHE_SHRINK_LIST		= BIT(10),
 	DCACHE_OP_WEAK_REVALIDATE	= BIT(11),
 	/*
···
 	DCACHE_PAR_LOOKUP		= BIT(24),	/* being looked up (with parent locked shared) */
 	DCACHE_DENTRY_CURSOR		= BIT(25),
 	DCACHE_NORCU			= BIT(26),	/* No RCU delay for freeing */
+	DCACHE_PERSISTENT		= BIT(27)
 };
 
 #define DCACHE_MANAGED_DENTRY \
···
 }
 
 void set_default_d_op(struct super_block *, const struct dentry_operations *);
+struct dentry *d_make_persistent(struct dentry *, struct inode *);
+void d_make_discardable(struct dentry *dentry);
 
 #endif	/* __LINUX_DCACHE_H */

include/linux/fs.h

···
 void generic_shutdown_super(struct super_block *sb);
 void kill_block_super(struct super_block *sb);
 void kill_anon_super(struct super_block *sb);
-void kill_litter_super(struct super_block *sb);
 void deactivate_super(struct super_block *sb);
 void deactivate_locked_super(struct super_block *sb);
 int set_anon_super(struct super_block *s, void *data);
···
 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);
+extern void __simple_unlink(struct inode *, struct dentry *);
+extern void __simple_rmdir(struct inode *, struct dentry *);
 void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry,
 			     struct inode *new_dir, struct dentry *new_dentry);
 extern int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
···
 			 struct dentry *, struct inode *, struct dentry *,
 			 unsigned int);
 extern void simple_recursive_removal(struct dentry *,
+                              void (*callback)(struct dentry *));
+extern void simple_remove_by_name(struct dentry *, const char *,
                               void (*callback)(struct dentry *));
 extern void locked_recursive_removal(struct dentry *,
                               void (*callback)(struct dentry *));
···
 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
 extern void simple_release_fs(struct vfsmount **mount, int *count);
 struct dentry *simple_start_creating(struct dentry *, const char *);
+void simple_done_creating(struct dentry *);
 
 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
 			loff_t *ppos, const void *from, size_t available);

include/linux/proc_fs.h

···
 
 struct proc_fs_info {
 	struct pid_namespace *pid_ns;
-	struct dentry *proc_self;        /* For /proc/self */
-	struct dentry *proc_thread_self; /* For /proc/thread-self */
 	kgid_t pid_gid;
 	enum proc_hidepid hide_pid;
 	enum proc_pidonly pidonly;

include/linux/security.h

···
 
 #endif
 
-#define securityfs_recursive_remove securityfs_remove
-
 #ifdef CONFIG_BPF_SYSCALL
 union bpf_attr;
 struct bpf_map;

init/do_mounts.c

···
 struct file_system_type rootfs_fs_type = {
 	.name		= "rootfs",
 	.init_fs_context = rootfs_init_fs_context,
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= kill_anon_super,
 };
 
 void __init init_rootfs(void)

ipc/mqueue.c

···
 	dir->i_size += DIRENT_SIZE;
 	simple_inode_init_ts(dir);
 
-	d_instantiate(dentry, inode);
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 	return 0;
 out_unlock:
 	spin_unlock(&mq_lock);
···
 
 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 {
-	struct inode *inode = d_inode(dentry);
-
-	simple_inode_init_ts(dir);
 	dir->i_size -= DIRENT_SIZE;
-	drop_nlink(inode);
-	dput(dentry);
-	return 0;
+	return simple_unlink(dir, dentry);
 }
 
 /*
···
 static struct file_system_type mqueue_fs_type = {
 	.name			= "mqueue",
 	.init_fs_context	= mqueue_init_fs_context,
-	.kill_sb		= kill_litter_super,
+	.kill_sb		= kill_anon_super,
 	.fs_flags		= FS_USERNS_MOUNT,
 };
 

kernel/bpf/inode.c

···
 static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode,
 				struct inode *dir)
 {
-	d_instantiate(dentry, inode);
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 }
···
 	struct dentry *dentry;
 	int ret;
 
-	inode_lock(parent->d_inode);
-	dentry = lookup_noperm(&QSTR(name), parent);
-	if (IS_ERR(dentry)) {
-		inode_unlock(parent->d_inode);
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
-	}
 	ret = bpf_mkobj_ops(dentry, mode, link, &bpf_link_iops,
 			    &bpf_iter_fops);
-	dput(dentry);
-	inode_unlock(parent->d_inode);
+	simple_done_creating(dentry);
 	return ret;
 }
 
···
 {
 	struct bpf_mount_opts *opts = sb->s_fs_info;
 
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 	kfree(opts);
 }
 

mm/shmem.c

···
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 	inode_inc_iversion(dir);
 
-	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
-		d_add(dentry, inode);
-	else
-		d_instantiate(dentry, inode);
-
-	dget(dentry); /* Extra count - pin the dentry in core */
+	d_make_persistent(dentry, inode);
 	return error;
 
 out_iput:
···
 		      struct dentry *dentry)
 {
 	struct inode *inode = d_inode(old_dentry);
-	int ret = 0;
+	int ret;
 
 	/*
 	 * No ordinary (disk based) filesystem counts links as inodes;
···
 	if (inode->i_nlink) {
 		ret = shmem_reserve_inode(inode->i_sb, NULL);
 		if (ret)
-			goto out;
+			return ret;
 	}
 
 	ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
 	if (ret) {
 		if (inode->i_nlink)
 			shmem_free_inode(inode->i_sb, 0);
-		goto out;
+		return ret;
 	}
 
 	dir->i_size += BOGO_DIRENT_SIZE;
-	inode_set_mtime_to_ts(dir,
-			      inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));
 	inode_inc_iversion(dir);
-	inc_nlink(inode);
-	ihold(inode);	/* New dentry reference */
-	dget(dentry);	/* Extra pinning count for the created dentry */
-	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
-		d_add(dentry, inode);
-	else
-		d_instantiate(dentry, inode);
-out:
-	return ret;
+	return simple_link(old_dentry, dir, dentry);
 }
 
 static int shmem_unlink(struct inode *dir, struct dentry *dentry)
···
 	simple_offset_remove(shmem_get_offset_ctx(dir), dentry);
 
 	dir->i_size -= BOGO_DIRENT_SIZE;
-	inode_set_mtime_to_ts(dir,
-			      inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));
 	inode_inc_iversion(dir);
-	drop_nlink(inode);
-	dput(dentry);	/* Undo the count from "create" - does all the work */
+	simple_unlink(dir, dentry);
 
 	/*
 	 * For now, VFS can't deal with case-insensitive negative dentries, so
···
 	dir->i_size += BOGO_DIRENT_SIZE;
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 	inode_inc_iversion(dir);
-	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
-		d_add(dentry, inode);
-	else
-		d_instantiate(dentry, inode);
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 	return 0;
 
 out_remove_offset:
···
 #ifdef CONFIG_TMPFS
 	.parameters	= shmem_fs_parameters,
 #endif
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= kill_anon_super,
 	.fs_flags	= FS_USERNS_MOUNT | FS_ALLOW_IDMAP | FS_MGTIME,
 };
 

net/sunrpc/rpc_pipe.c

···
 
 	inode = rpc_get_inode(dir->i_sb, S_IFREG | mode);
 	if (unlikely(!inode)) {
-		dput(dentry);
-		inode_unlock(dir);
+		simple_done_creating(dentry);
 		return -ENOMEM;
 	}
 	inode->i_ino = iunique(dir->i_sb, 100);
 	if (i_fop)
 		inode->i_fop = i_fop;
 	rpc_inode_setowner(inode, private);
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	fsnotify_create(dir, dentry);
-	inode_unlock(dir);
+	simple_done_creating(dentry);
 	return 0;
 }
 
···
 
 	inode = rpc_get_inode(dir->i_sb, S_IFDIR | mode);
 	if (unlikely(!inode)) {
-		dput(dentry);
-		inode_unlock(dir);
+		simple_done_creating(dentry);
 		return ERR_PTR(-ENOMEM);
 	}
 
 	inode->i_ino = iunique(dir->i_sb, 100);
 	inc_nlink(dir);
-	d_instantiate(dentry, inode);
+	d_make_persistent(dentry, inode);
 	fsnotify_mkdir(dir, dentry);
-	inode_unlock(dir);
+	simple_done_creating(dentry);
 
-	return dentry;
+	return dentry; // borrowed
 }
 
 static int rpc_populate(struct dentry *parent,
···
 
 	inode = rpc_get_inode(dir->i_sb, umode);
 	if (unlikely(!inode)) {
-		dput(dentry);
-		inode_unlock(dir);
+		simple_done_creating(dentry);
 		err = -ENOMEM;
 		goto failed;
 	}
···
 	rpci->private = private;
 	rpci->pipe = pipe;
 	rpc_inode_setowner(inode, private);
-	d_instantiate(dentry, inode);
-	pipe->dentry = dentry;
+	pipe->dentry = dentry; // borrowed
+	d_make_persistent(dentry, inode);
 	fsnotify_create(dir, dentry);
-	inode_unlock(dir);
+	simple_done_creating(dentry);
 	return 0;
 
 failed:
···
 					   sb);
 	mutex_unlock(&sn->pipefs_sb_lock);
 out:
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 	put_net(net);
 }
 

security/apparmor/apparmorfs.c

···
 	dir = d_inode(dentry->d_parent);
 	dentry = start_removing_dentry(dentry->d_parent, dentry);
 	if (!IS_ERR(dentry) && simple_positive(dentry)) {
-		if (d_is_dir(dentry))
-			simple_rmdir(dir, dentry);
-		else
-			simple_unlink(dir, dentry);
+		if (d_is_dir(dentry)) {
+			if (!WARN_ON(!simple_empty(dentry))) {
+				__simple_rmdir(dir, dentry);
+				dput(dentry);
+			}
+		} else {
+			__simple_unlink(dir, dentry);
+			dput(dentry);
+		}
 		d_delete(dentry);
 	}
 	end_removing(dentry);

security/inode.c

···
 	.owner =	THIS_MODULE,
 	.name =		"securityfs",
 	.init_fs_context = securityfs_init_fs_context,
-	.kill_sb =	kill_litter_super,
+	.kill_sb =	kill_anon_super,
 };
 
 /**
···
 		parent = mount->mnt_root;
 	}
 
+	inode = new_inode(parent->d_sb);
+	if (unlikely(!inode)) {
+		dentry = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
 	dir = d_inode(parent);
 
-	inode_lock(dir);
-	dentry = lookup_noperm(&QSTR(name), parent);
-	if (IS_ERR(dentry))
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry)) {
+		iput(inode);
 		goto out;
-
-	if (d_really_is_positive(dentry)) {
-		error = -EEXIST;
-		goto out1;
 	}
-
-	inode = new_inode(dir->i_sb);
-	if (!inode) {
-		error = -ENOMEM;
-		goto out1;
-	}
-
 	inode->i_ino = get_next_ino();
 	inode->i_mode = mode;
 	simple_inode_init_ts(inode);
···
 	} else {
 		inode->i_fop = fops;
 	}
-	d_instantiate(dentry, inode);
-	inode_unlock(dir);
-	return dentry;
+	d_make_persistent(dentry, inode);
+	simple_done_creating(dentry);
+	return dentry; // borrowed
 
-out1:
-	dput(dentry);
-	dentry = ERR_PTR(error);
 out:
-	inode_unlock(dir);
 	if (pinned)
 		simple_release_fs(&mount, &mount_count);
 	return dentry;

security/selinux/selinuxfs.c

···
 	struct dentry *class_dir;
 	unsigned long last_class_ino;
 	bool policy_opened;
-	struct dentry *policycap_dir;
 	unsigned long last_ino;
 	struct super_block *sb;
 };
···
 
 #define BOOL_DIR_NAME "booleans"
 #define CLASS_DIR_NAME "class"
-#define POLICYCAP_DIR_NAME "policy_capabilities"
 
 #define TMPBUFLEN	12
 static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
···
 	return ret;
 }
 
+static struct dentry *sel_attach(struct dentry *parent, const char *name,
+				 struct inode *inode)
+{
+	struct dentry *dentry = d_alloc_name(parent, name);
+	if (unlikely(!dentry)) {
+		iput(inode);
+		return ERR_PTR(-ENOMEM);
+	}
+	d_make_persistent(dentry, inode);
+	dput(dentry);
+	return dentry;
+}
+
+static int sel_attach_file(struct dentry *parent, const char *name,
+			   struct inode *inode)
+{
+	struct dentry *dentry = sel_attach(parent, name, inode);
+	return PTR_ERR_OR_ZERO(dentry);
+}
+
 static ssize_t sel_read_bool(struct file *filep, char __user *buf,
 			     size_t count, loff_t *ppos)
 {
···
 	*bool_num = num;
 	*bool_pending_names = names;
 
-	for (i = 0; i < num; i++) {
-		struct dentry *dentry;
+	for (i = 0; !ret && i < num; i++) {
 		struct inode *inode;
 		struct inode_security_struct *isec;
 		ssize_t len;
···
 			ret = -ENAMETOOLONG;
 			break;
 		}
-		dentry = d_alloc_name(bool_dir, names[i]);
-		if (!dentry) {
-			ret = -ENOMEM;
-			break;
-		}
 
 		inode = sel_make_inode(bool_dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
 		if (!inode) {
-			dput(dentry);
 			ret = -ENOMEM;
 			break;
 		}
···
 		isec->initialized = LABEL_INITIALIZED;
 		inode->i_fop = &sel_bool_ops;
 		inode->i_ino = i|SEL_BOOL_INO_OFFSET;
-		d_add(dentry, inode);
+
+		ret = sel_attach_file(bool_dir, names[i], inode);
 	}
 out:
 	free_page((unsigned long)page);
···
 	struct super_block *sb = dir->d_sb;
 	struct selinux_fs_info *fsi = sb->s_fs_info;
 	unsigned int i;
+	int err = 0;
 	static const struct tree_descr files[] = {
 		{ "cache_threshold",
 		  &sel_avc_cache_threshold_ops, S_IRUGO|S_IWUSR },
···
 #endif
 	};
 
-	for (i = 0; i < ARRAY_SIZE(files); i++) {
+	for (i = 0; !err && i < ARRAY_SIZE(files); i++) {
 		struct inode *inode;
-		struct dentry *dentry;
-
-		dentry = d_alloc_name(dir, files[i].name);
-		if (!dentry)
-			return -ENOMEM;
 
 		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
-		if (!inode) {
-			dput(dentry);
+		if (!inode)
 			return -ENOMEM;
-		}
 
 		inode->i_fop = files[i].ops;
 		inode->i_ino = ++fsi->last_ino;
-		d_add(dentry, inode);
+
+		err = sel_attach_file(dir, files[i].name, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static int sel_make_ss_files(struct dentry *dir)
···
 	struct super_block *sb = dir->d_sb;
 	struct selinux_fs_info *fsi = sb->s_fs_info;
 	unsigned int i;
+	int err = 0;
 	static const struct tree_descr files[] = {
 		{ "sidtab_hash_stats", &sel_sidtab_hash_stats_ops, S_IRUGO },
 	};
 
-	for (i = 0; i < ARRAY_SIZE(files); i++) {
+	for (i = 0; !err && i < ARRAY_SIZE(files); i++) {
 		struct inode *inode;
-		struct dentry *dentry;
-
-		dentry = d_alloc_name(dir, files[i].name);
-		if (!dentry)
-			return -ENOMEM;
 
 		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
-		if (!inode) {
-			dput(dentry);
+		if (!inode)
 			return -ENOMEM;
-		}
 
 		inode->i_fop = files[i].ops;
 		inode->i_ino = ++fsi->last_ino;
-		d_add(dentry, inode);
+
+		err = sel_attach_file(dir, files[i].name, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static ssize_t sel_read_initcon(struct file *file, char __user *buf,
···
 static int sel_make_initcon_files(struct dentry *dir)
 {
 	unsigned int i;
+	int err = 0;
 
-	for (i = 1; i <= SECINITSID_NUM; i++) {
-		struct inode *inode;
-		struct dentry *dentry;
+	for (i = 1; !err && i <= SECINITSID_NUM; i++) {
 		const char *s = security_get_initial_sid_context(i);
+		struct inode *inode;
 
 		if (!s)
 			continue;
-		dentry = d_alloc_name(dir, s);
-		if (!dentry)
-			return -ENOMEM;
 
 		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
-		if (!inode) {
-			dput(dentry);
+		if (!inode)
 			return -ENOMEM;
-		}
 
 		inode->i_fop = &sel_initcon_ops;
 		inode->i_ino = i|SEL_INITCON_INO_OFFSET;
-		d_add(dentry, inode);
+		err = sel_attach_file(dir, s, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static inline unsigned long sel_class_to_ino(u16 class)
···
 	if (rc)
 		return rc;
 
-	for (i = 0; i < nperms; i++) {
+	for (i = 0; !rc && i < nperms; i++) {
 		struct inode *inode;
-		struct dentry *dentry;
 
-		rc = -ENOMEM;
-		dentry = d_alloc_name(dir, perms[i]);
-		if (!dentry)
-			goto out;
-
-		rc = -ENOMEM;
 		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
 		if (!inode) {
-			dput(dentry);
-			goto out;
+			rc = -ENOMEM;
+			break;
 		}
 
 		inode->i_fop = &sel_perm_ops;
 		/* i+1 since perm values are 1-indexed */
 		inode->i_ino = sel_perm_to_ino(classvalue, i + 1);
-		d_add(dentry, inode);
+
+		rc = sel_attach_file(dir, perms[i], inode);
 	}
-	rc = 0;
-out:
 	for (i = 0; i < nperms; i++)
 		kfree(perms[i]);
 	kfree(perms);
···
 	struct selinux_fs_info *fsi = sb->s_fs_info;
 	struct dentry *dentry = NULL;
 	struct inode *inode = NULL;
-
-	dentry = d_alloc_name(dir, "index");
-	if (!dentry)
-		return -ENOMEM;
+	int err;
 
 	inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		return -ENOMEM;
-	}
 
 	inode->i_fop = &sel_class_ops;
 	inode->i_ino = sel_class_to_ino(index);
-	d_add(dentry, inode);
+
+	err = sel_attach_file(dir, "index", inode);
+	if (err)
+		return err;
 
 	dentry = sel_make_dir(dir, "perms", &fsi->last_class_ino);
 	if (IS_ERR(dentry))
···
 	return rc;
 }
 
-static int sel_make_policycap(struct selinux_fs_info *fsi)
+static int sel_make_policycap(struct dentry *dir)
 {
+	struct super_block *sb = dir->d_sb;
 	unsigned int iter;
-	struct dentry *dentry = NULL;
 	struct inode *inode = NULL;
+	int err = 0;
 
-	for (iter = 0; iter <= POLICYDB_CAP_MAX; iter++) {
+	for (iter = 0; !err && iter <= POLICYDB_CAP_MAX; iter++) {
+		const char *name;
+
 		if (iter < ARRAY_SIZE(selinux_policycap_names))
-			dentry = d_alloc_name(fsi->policycap_dir,
-					      selinux_policycap_names[iter]);
+			name = selinux_policycap_names[iter];
 		else
-			dentry = d_alloc_name(fsi->policycap_dir, "unknown");
+			name = "unknown";
 
-		if (dentry == NULL)
+		inode = sel_make_inode(sb, S_IFREG | 0444);
+		if (!inode)
 			return -ENOMEM;
-
-		inode = sel_make_inode(fsi->sb, S_IFREG | 0444);
-		if (inode == NULL) {
-			dput(dentry);
-			return -ENOMEM;
-		}
 
 		inode->i_fop = &sel_policycap_ops;
 		inode->i_ino = iter | SEL_POLICYCAP_INO_OFFSET;
-		d_add(dentry, inode);
+		err = sel_attach_file(dir, name, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
 			unsigned long *ino)
 {
-	struct dentry *dentry = d_alloc_name(dir, name);
 	struct inode *inode;
 
-	if (!dentry)
-		return ERR_PTR(-ENOMEM);
-
 	inode = sel_make_inode(dir->d_sb, S_IFDIR | S_IRUGO | S_IXUGO);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	inode->i_op = &simple_dir_inode_operations;
 	inode->i_fop = &simple_dir_operations;
 	inode->i_ino = ++(*ino);
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
-	d_add(dentry, inode);
 	/* bump link count on parent directory, too */
 	inc_nlink(d_inode(dir));
 
-	return dentry;
+	return sel_attach(dir, name, inode);
 }
 
 static int reject_all(struct mnt_idmap *idmap, struct inode *inode, int mask)
···
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
 	inode_lock(sb->s_root->d_inode);
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
 	inc_nlink(sb->s_root->d_inode);
 	inode_unlock(sb->s_root->d_inode);
-	return dentry;
+	dput(dentry);
+	return dentry;	// borrowed
 }
 
 #define NULL_FILE_NAME "null"
···
 	}
 
 	ret = -ENOMEM;
-	dentry = d_alloc_name(sb->s_root, NULL_FILE_NAME);
-	if (!dentry)
-		goto err;
-
-	ret = -ENOMEM;
 	inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		goto err;
-	}
 
 	inode->i_ino = ++fsi->last_ino;
 	isec = selinux_inode(inode);
···
 	isec->initialized = LABEL_INITIALIZED;
 
 	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
-	d_add(dentry, inode);
+	ret = sel_attach_file(sb->s_root, NULL_FILE_NAME, inode);
+	if (ret)
+		goto err;
 
 	dentry = sel_make_dir(sb->s_root, "avc", &fsi->last_ino);
 	if (IS_ERR(dentry)) {
···
 		goto err;
 	}
 
-	fsi->policycap_dir = sel_make_dir(sb->s_root, POLICYCAP_DIR_NAME,
-					  &fsi->last_ino);
-	if (IS_ERR(fsi->policycap_dir)) {
-		ret = PTR_ERR(fsi->policycap_dir);
-		fsi->policycap_dir = NULL;
+	dentry = sel_make_dir(sb->s_root, "policy_capabilities", &fsi->last_ino);
+	if (IS_ERR(dentry)) {
+		ret = PTR_ERR(dentry);
 		goto err;
 	}
 
-	ret = sel_make_policycap(fsi);
+	ret = sel_make_policycap(dentry);
 	if (ret) {
 		pr_err("SELinux: failed to load policy capabilities\n");
 		goto err;
···
 static void sel_kill_sb(struct super_block *sb)
 {
 	selinux_fs_info_free(sb);
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 }
 
 static struct file_system_type sel_fs_type = {

security/smack/smackfs.c

···
 static struct file_system_type smk_fs_type = {
 	.name		= "smackfs",
 	.init_fs_context = smk_init_fs_context,
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= kill_anon_super,
 };
 
 static struct vfsmount *smackfs_mount;