fs/vboxsf/dir.c - linux - Git at Google

 // SPDX-License-Identifier: MIT
 /*
  * VirtualBox Guest Shared Folders support: Directory inode and file operations
  *
  * Copyright (C) 2006-2018 Oracle Corporation
  */

 #include <linux/namei.h>
 #include <linux/vbox_utils.h>
 #include "vfsmod.h"

 static int vboxsf_dir_open(struct inode *inode, struct file *file)
 {
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb);
 	struct shfl_createparms params = {};
 	struct vboxsf_dir_info *sf_d;
 	int err;

 	sf_d = vboxsf_dir_info_alloc();
 	if (!sf_d)
 		return -ENOMEM;

 	params.handle = SHFL_HANDLE_NIL;
 	params.create_flags = SHFL_CF_DIRECTORY | SHFL_CF_ACT_OPEN_IF_EXISTS |
 			      SHFL_CF_ACT_FAIL_IF_NEW | SHFL_CF_ACCESS_READ;

 	err = vboxsf_create_at_dentry(file_dentry(file), &params);
 	if (err)
 		goto err_free_dir_info;

 	if (params.result != SHFL_FILE_EXISTS) {
 		err = -ENOENT;
 		goto err_close;
 	}

 	err = vboxsf_dir_read_all(sbi, sf_d, params.handle);
 	if (err)
 		goto err_close;

 	vboxsf_close(sbi->root, params.handle);
 	file->private_data = sf_d;
 	return 0;

 err_close:
 	vboxsf_close(sbi->root, params.handle);
 err_free_dir_info:
 	vboxsf_dir_info_free(sf_d);
 	return err;
 }

 static int vboxsf_dir_release(struct inode *inode, struct file *file)
 {
 	if (file->private_data)
 		vboxsf_dir_info_free(file->private_data);

 	return 0;
 }

 static unsigned int vboxsf_get_d_type(u32 mode)
 {
 	unsigned int d_type;

 	switch (mode & SHFL_TYPE_MASK) {
 	case SHFL_TYPE_FIFO:
 		d_type = DT_FIFO;
 		break;
 	case SHFL_TYPE_DEV_CHAR:
 		d_type = DT_CHR;
 		break;
 	case SHFL_TYPE_DIRECTORY:
 		d_type = DT_DIR;
 		break;
 	case SHFL_TYPE_DEV_BLOCK:
 		d_type = DT_BLK;
 		break;
 	case SHFL_TYPE_FILE:
 		d_type = DT_REG;
 		break;
 	case SHFL_TYPE_SYMLINK:
 		d_type = DT_LNK;
 		break;
 	case SHFL_TYPE_SOCKET:
 		d_type = DT_SOCK;
 		break;
 	case SHFL_TYPE_WHITEOUT:
 		d_type = DT_WHT;
 		break;
 	default:
 		d_type = DT_UNKNOWN;
 		break;
 	}
 	return d_type;
 }

 static bool vboxsf_dir_emit(struct file *dir, struct dir_context *ctx)
 {
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(file_inode(dir)->i_sb);
 	struct vboxsf_dir_info *sf_d = dir->private_data;
 	struct shfl_dirinfo *info;
 	struct vboxsf_dir_buf *b;
 	unsigned int d_type;
 	loff_t i, cur = 0;
 	ino_t fake_ino;
 	void *end;
 	int err;

 	list_for_each_entry(b, &sf_d->info_list, head) {
 try_next_entry:
 		if (ctx->pos >= cur + b->entries) {
 			cur += b->entries;
 			continue;
 		}

 		/*
 		 * Note the vboxsf_dir_info objects we are iterating over here
 		 * are variable sized, so the info pointer may end up being
 		 * unaligned. This is how we get the data from the host.
 		 * Since vboxsf is only supported on x86 machines this is not
 		 * a problem.
 		 */
 		for (i = 0, info = b->buf; i < ctx->pos - cur; i++) {
 			end = &info->name.string.utf8[info->name.size];
 			/* Only happens if the host gives us corrupt data */
 			if (WARN_ON(end > (b->buf + b->used)))
 				return false;
 			info = end;
 		}

 		end = &info->name.string.utf8[info->name.size];
 		if (WARN_ON(end > (b->buf + b->used)))
 			return false;

 		/* Info now points to the right entry, emit it. */
 		d_type = vboxsf_get_d_type(info->info.attr.mode);

 		/*
 		 * On 32-bit systems pos is 64-bit signed, while ino is 32-bit
 		 * unsigned so fake_ino may overflow, check for this.
 		 */
 		if ((ino_t)(ctx->pos + 1) != (u64)(ctx->pos + 1)) {
 			vbg_err("vboxsf: fake ino overflow, truncating dir\n");
 			return false;
 		}
 		fake_ino = ctx->pos + 1;

 		if (sbi->nls) {
 			char d_name[NAME_MAX];

 			err = vboxsf_nlscpy(sbi, d_name, NAME_MAX,
 					    info->name.string.utf8,
 					    info->name.length);
 			if (err) {
 				/* skip erroneous entry and proceed */
 				ctx->pos += 1;
 				goto try_next_entry;
 			}

 			return dir_emit(ctx, d_name, strlen(d_name),
 					fake_ino, d_type);
 		}

 		return dir_emit(ctx, info->name.string.utf8, info->name.length,
 				fake_ino, d_type);
 	}

 	return false;
 }

 static int vboxsf_dir_iterate(struct file *dir, struct dir_context *ctx)
 {
 	bool emitted;

 	do {
 		emitted = vboxsf_dir_emit(dir, ctx);
 		if (emitted)
 			ctx->pos += 1;
 	} while (emitted);

 	return 0;
 }

 const struct file_operations vboxsf_dir_fops = {
 	.open = vboxsf_dir_open,
 	.iterate = vboxsf_dir_iterate,
 	.release = vboxsf_dir_release,
 	.read = generic_read_dir,
 	.llseek = generic_file_llseek,
 };

 /*
  * This is called during name resolution/lookup to check if the @dentry in
  * the cache is still valid. the job is handled by vboxsf_inode_revalidate.
  */
 static int vboxsf_dentry_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;

 	if (d_really_is_positive(dentry))
 		return vboxsf_inode_revalidate(dentry) == 0;
 	else
 		return vboxsf_stat_dentry(dentry, NULL) == -ENOENT;
 }

 const struct dentry_operations vboxsf_dentry_ops = {
 	.d_revalidate = vboxsf_dentry_revalidate
 };

 /* iops */

 static struct dentry *vboxsf_dir_lookup(struct inode *parent,
 					struct dentry *dentry,
 					unsigned int flags)
 {
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 	struct shfl_fsobjinfo fsinfo;
 	struct inode *inode;
 	int err;

 	dentry->d_time = jiffies;

 	err = vboxsf_stat_dentry(dentry, &fsinfo);
 	if (err) {
 		inode = (err == -ENOENT) ? NULL : ERR_PTR(err);
 	} else {
 		inode = vboxsf_new_inode(parent->i_sb);
 		if (!IS_ERR(inode))
 			vboxsf_init_inode(sbi, inode, &fsinfo);
 	}

 	return d_splice_alias(inode, dentry);
 }

 static int vboxsf_dir_instantiate(struct inode *parent, struct dentry *dentry,
 				  struct shfl_fsobjinfo *info)
 {
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 	struct vboxsf_inode *sf_i;
 	struct inode *inode;

 	inode = vboxsf_new_inode(parent->i_sb);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);

 	sf_i = VBOXSF_I(inode);
 	/* The host may have given us different attr then requested */
 	sf_i->force_restat = 1;
 	vboxsf_init_inode(sbi, inode, info);

 	d_instantiate(dentry, inode);

 	return 0;
 }

 static int vboxsf_dir_create(struct inode *parent, struct dentry *dentry,
 			     umode_t mode, int is_dir)
 {
 	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 	struct shfl_createparms params = {};
 	int err;

 	params.handle = SHFL_HANDLE_NIL;
 	params.create_flags = SHFL_CF_ACT_CREATE_IF_NEW |
 			      SHFL_CF_ACT_FAIL_IF_EXISTS |
 			      SHFL_CF_ACCESS_READWRITE |
 			      (is_dir ? SHFL_CF_DIRECTORY : 0);
 	params.info.attr.mode = (mode & 0777) |
 				(is_dir ? SHFL_TYPE_DIRECTORY : SHFL_TYPE_FILE);
 	params.info.attr.additional = SHFLFSOBJATTRADD_NOTHING;

 	err = vboxsf_create_at_dentry(dentry, &params);
 	if (err)
 		return err;

 	if (params.result != SHFL_FILE_CREATED)
 		return -EPERM;

 	vboxsf_close(sbi->root, params.handle);

 	err = vboxsf_dir_instantiate(parent, dentry, &params.info);
 	if (err)
 		return err;

 	/* parent directory access/change time changed */
 	sf_parent_i->force_restat = 1;

 	return 0;
 }

 static int vboxsf_dir_mkfile(struct user_namespace *mnt_userns,
 			     struct inode *parent, struct dentry *dentry,
 			     umode_t mode, bool excl)
 {
 	return vboxsf_dir_create(parent, dentry, mode, 0);
 }

 static int vboxsf_dir_mkdir(struct user_namespace *mnt_userns,
 			    struct inode *parent, struct dentry *dentry,
 			    umode_t mode)
 {
 	return vboxsf_dir_create(parent, dentry, mode, 1);
 }

 static int vboxsf_dir_unlink(struct inode *parent, struct dentry *dentry)
 {
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 	struct inode *inode = d_inode(dentry);
 	struct shfl_string *path;
 	u32 flags;
 	int err;

 	if (S_ISDIR(inode->i_mode))
 		flags = SHFL_REMOVE_DIR;
 	else
 		flags = SHFL_REMOVE_FILE;

 	if (S_ISLNK(inode->i_mode))
 		flags |= SHFL_REMOVE_SYMLINK;

 	path = vboxsf_path_from_dentry(sbi, dentry);
 	if (IS_ERR(path))
 		return PTR_ERR(path);

 	err = vboxsf_remove(sbi->root, path, flags);
 	__putname(path);
 	if (err)
 		return err;

 	/* parent directory access/change time changed */
 	sf_parent_i->force_restat = 1;

 	return 0;
 }

 static int vboxsf_dir_rename(struct user_namespace *mnt_userns,
 			     struct inode *old_parent,
 			     struct dentry *old_dentry,
 			     struct inode *new_parent,
 			     struct dentry *new_dentry,
 			     unsigned int flags)
 {
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(old_parent->i_sb);
 	struct vboxsf_inode *sf_old_parent_i = VBOXSF_I(old_parent);
 	struct vboxsf_inode *sf_new_parent_i = VBOXSF_I(new_parent);
 	u32 shfl_flags = SHFL_RENAME_FILE | SHFL_RENAME_REPLACE_IF_EXISTS;
 	struct shfl_string *old_path, *new_path;
 	int err;

 	if (flags)
 		return -EINVAL;

 	old_path = vboxsf_path_from_dentry(sbi, old_dentry);
 	if (IS_ERR(old_path))
 		return PTR_ERR(old_path);

 	new_path = vboxsf_path_from_dentry(sbi, new_dentry);
 	if (IS_ERR(new_path)) {
 		err = PTR_ERR(new_path);
 		goto err_put_old_path;
 	}

 	if (d_inode(old_dentry)->i_mode & S_IFDIR)
 		shfl_flags = 0;

 	err = vboxsf_rename(sbi->root, old_path, new_path, shfl_flags);
 	if (err == 0) {
 		/* parent directories access/change time changed */
 		sf_new_parent_i->force_restat = 1;
 		sf_old_parent_i->force_restat = 1;
 	}

 	__putname(new_path);
 err_put_old_path:
 	__putname(old_path);
 	return err;
 }

 static int vboxsf_dir_symlink(struct user_namespace *mnt_userns,
 			      struct inode *parent, struct dentry *dentry,
 			      const char *symname)
 {
 	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 	int symname_size = strlen(symname) + 1;
 	struct shfl_string *path, *ssymname;
 	struct shfl_fsobjinfo info;
 	int err;

 	path = vboxsf_path_from_dentry(sbi, dentry);
 	if (IS_ERR(path))
 		return PTR_ERR(path);

 	ssymname = kmalloc(SHFLSTRING_HEADER_SIZE + symname_size, GFP_KERNEL);
 	if (!ssymname) {
 		__putname(path);
 		return -ENOMEM;
 	}
 	ssymname->length = symname_size - 1;
 	ssymname->size = symname_size;
 	memcpy(ssymname->string.utf8, symname, symname_size);

 	err = vboxsf_symlink(sbi->root, path, ssymname, &info);
 	kfree(ssymname);
 	__putname(path);
 	if (err) {
 		/* -EROFS means symlinks are note support -> -EPERM */
 		return (err == -EROFS) ? -EPERM : err;
 	}

 	err = vboxsf_dir_instantiate(parent, dentry, &info);
 	if (err)
 		return err;

 	/* parent directory access/change time changed */
 	sf_parent_i->force_restat = 1;
 	return 0;
 }

 const struct inode_operations vboxsf_dir_iops = {
 	.lookup  = vboxsf_dir_lookup,
 	.create  = vboxsf_dir_mkfile,
 	.mkdir   = vboxsf_dir_mkdir,
 	.rmdir   = vboxsf_dir_unlink,
 	.unlink  = vboxsf_dir_unlink,
 	.rename  = vboxsf_dir_rename,
 	.symlink = vboxsf_dir_symlink,
 	.getattr = vboxsf_getattr,
 	.setattr = vboxsf_setattr,
 };
	// SPDX-License-Identifier: MIT
	/*
	* VirtualBox Guest Shared Folders support: Directory inode and file operations
	*
	* Copyright (C) 2006-2018 Oracle Corporation
	*/

	#include <linux/namei.h>
	#include <linux/vbox_utils.h>
	#include "vfsmod.h"

	static int vboxsf_dir_open(struct inode inode, struct file file)
	{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb);
	struct shfl_createparms params = {};
	struct vboxsf_dir_info *sf_d;
	int err;

	sf_d = vboxsf_dir_info_alloc();
	if (!sf_d)
	return -ENOMEM;

	params.handle = SHFL_HANDLE_NIL;
	params.create_flags = SHFL_CF_DIRECTORY \| SHFL_CF_ACT_OPEN_IF_EXISTS \|
	SHFL_CF_ACT_FAIL_IF_NEW \| SHFL_CF_ACCESS_READ;

	err = vboxsf_create_at_dentry(file_dentry(file), &params);
	if (err)
	goto err_free_dir_info;

	if (params.result != SHFL_FILE_EXISTS) {
	err = -ENOENT;
	goto err_close;
	}

	err = vboxsf_dir_read_all(sbi, sf_d, params.handle);
	if (err)
	goto err_close;

	vboxsf_close(sbi->root, params.handle);
	file->private_data = sf_d;
	return 0;

	err_close:
	vboxsf_close(sbi->root, params.handle);
	err_free_dir_info:
	vboxsf_dir_info_free(sf_d);
	return err;
	}

	static int vboxsf_dir_release(struct inode inode, struct file file)
	{
	if (file->private_data)
	vboxsf_dir_info_free(file->private_data);

	return 0;
	}

	static unsigned int vboxsf_get_d_type(u32 mode)
	{
	unsigned int d_type;

	switch (mode & SHFL_TYPE_MASK) {
	case SHFL_TYPE_FIFO:
	d_type = DT_FIFO;
	break;
	case SHFL_TYPE_DEV_CHAR:
	d_type = DT_CHR;
	break;
	case SHFL_TYPE_DIRECTORY:
	d_type = DT_DIR;
	break;
	case SHFL_TYPE_DEV_BLOCK:
	d_type = DT_BLK;
	break;
	case SHFL_TYPE_FILE:
	d_type = DT_REG;
	break;
	case SHFL_TYPE_SYMLINK:
	d_type = DT_LNK;
	break;
	case SHFL_TYPE_SOCKET:
	d_type = DT_SOCK;
	break;
	case SHFL_TYPE_WHITEOUT:
	d_type = DT_WHT;
	break;
	default:
	d_type = DT_UNKNOWN;
	break;
	}
	return d_type;
	}

	static bool vboxsf_dir_emit(struct file dir, struct dir_context ctx)
	{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(file_inode(dir)->i_sb);
	struct vboxsf_dir_info *sf_d = dir->private_data;
	struct shfl_dirinfo *info;
	struct vboxsf_dir_buf *b;
	unsigned int d_type;
	loff_t i, cur = 0;
	ino_t fake_ino;
	void *end;
	int err;

	list_for_each_entry(b, &sf_d->info_list, head) {
	try_next_entry:
	if (ctx->pos >= cur + b->entries) {
	cur += b->entries;
	continue;
	}

	/*
	* Note the vboxsf_dir_info objects we are iterating over here
	* are variable sized, so the info pointer may end up being
	* unaligned. This is how we get the data from the host.
	* Since vboxsf is only supported on x86 machines this is not
	* a problem.
	*/
	for (i = 0, info = b->buf; i < ctx->pos - cur; i++) {
	end = &info->name.string.utf8[info->name.size];
	/* Only happens if the host gives us corrupt data */
	if (WARN_ON(end > (b->buf + b->used)))
	return false;
	info = end;
	}

	end = &info->name.string.utf8[info->name.size];
	if (WARN_ON(end > (b->buf + b->used)))
	return false;

	/* Info now points to the right entry, emit it. */
	d_type = vboxsf_get_d_type(info->info.attr.mode);

	/*
	* On 32-bit systems pos is 64-bit signed, while ino is 32-bit
	* unsigned so fake_ino may overflow, check for this.
	*/
	if ((ino_t)(ctx->pos + 1) != (u64)(ctx->pos + 1)) {
	vbg_err("vboxsf: fake ino overflow, truncating dir\n");
	return false;
	}
	fake_ino = ctx->pos + 1;

	if (sbi->nls) {
	char d_name[NAME_MAX];

	err = vboxsf_nlscpy(sbi, d_name, NAME_MAX,
	info->name.string.utf8,
	info->name.length);
	if (err) {
	/* skip erroneous entry and proceed */
	ctx->pos += 1;
	goto try_next_entry;
	}

	return dir_emit(ctx, d_name, strlen(d_name),
	fake_ino, d_type);
	}

	return dir_emit(ctx, info->name.string.utf8, info->name.length,
	fake_ino, d_type);
	}

	return false;
	}

	static int vboxsf_dir_iterate(struct file dir, struct dir_context ctx)
	{
	bool emitted;

	do {
	emitted = vboxsf_dir_emit(dir, ctx);
	if (emitted)
	ctx->pos += 1;
	} while (emitted);

	return 0;
	}

	const struct file_operations vboxsf_dir_fops = {
	.open = vboxsf_dir_open,
	.iterate = vboxsf_dir_iterate,
	.release = vboxsf_dir_release,
	.read = generic_read_dir,
	.llseek = generic_file_llseek,
	};

	/*
	* This is called during name resolution/lookup to check if the @dentry in
	* the cache is still valid. the job is handled by vboxsf_inode_revalidate.
	*/
	static int vboxsf_dentry_revalidate(struct dentry *dentry, unsigned int flags)
	{
	if (flags & LOOKUP_RCU)
	return -ECHILD;

	if (d_really_is_positive(dentry))
	return vboxsf_inode_revalidate(dentry) == 0;
	else
	return vboxsf_stat_dentry(dentry, NULL) == -ENOENT;
	}

	const struct dentry_operations vboxsf_dentry_ops = {
	.d_revalidate = vboxsf_dentry_revalidate
	};

	/* iops */

	static struct dentry vboxsf_dir_lookup(struct inode parent,
	struct dentry *dentry,
	unsigned int flags)
	{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
	struct shfl_fsobjinfo fsinfo;
	struct inode *inode;
	int err;

	dentry->d_time = jiffies;

	err = vboxsf_stat_dentry(dentry, &fsinfo);
	if (err) {
	inode = (err == -ENOENT) ? NULL : ERR_PTR(err);
	} else {
	inode = vboxsf_new_inode(parent->i_sb);
	if (!IS_ERR(inode))
	vboxsf_init_inode(sbi, inode, &fsinfo);
	}

	return d_splice_alias(inode, dentry);
	}

	static int vboxsf_dir_instantiate(struct inode parent, struct dentry dentry,
	struct shfl_fsobjinfo *info)
	{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
	struct vboxsf_inode *sf_i;
	struct inode *inode;

	inode = vboxsf_new_inode(parent->i_sb);
	if (IS_ERR(inode))
	return PTR_ERR(inode);

	sf_i = VBOXSF_I(inode);
	/* The host may have given us different attr then requested */
	sf_i->force_restat = 1;
	vboxsf_init_inode(sbi, inode, info);

	d_instantiate(dentry, inode);

	return 0;
	}

	static int vboxsf_dir_create(struct inode parent, struct dentry dentry,
	umode_t mode, int is_dir)
	{
	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
	struct shfl_createparms params = {};
	int err;

	params.handle = SHFL_HANDLE_NIL;
	params.create_flags = SHFL_CF_ACT_CREATE_IF_NEW \|
	SHFL_CF_ACT_FAIL_IF_EXISTS \|
	SHFL_CF_ACCESS_READWRITE \|
	(is_dir ? SHFL_CF_DIRECTORY : 0);
	params.info.attr.mode = (mode & 0777) \|
	(is_dir ? SHFL_TYPE_DIRECTORY : SHFL_TYPE_FILE);
	params.info.attr.additional = SHFLFSOBJATTRADD_NOTHING;

	err = vboxsf_create_at_dentry(dentry, &params);
	if (err)
	return err;

	if (params.result != SHFL_FILE_CREATED)
	return -EPERM;

	vboxsf_close(sbi->root, params.handle);

	err = vboxsf_dir_instantiate(parent, dentry, &params.info);
	if (err)
	return err;

	/* parent directory access/change time changed */
	sf_parent_i->force_restat = 1;

	return 0;
	}

	static int vboxsf_dir_mkfile(struct user_namespace *mnt_userns,
	struct inode parent, struct dentry dentry,
	umode_t mode, bool excl)
	{
	return vboxsf_dir_create(parent, dentry, mode, 0);
	}

	static int vboxsf_dir_mkdir(struct user_namespace *mnt_userns,
	struct inode parent, struct dentry dentry,
	umode_t mode)
	{
	return vboxsf_dir_create(parent, dentry, mode, 1);
	}

	static int vboxsf_dir_unlink(struct inode parent, struct dentry dentry)
	{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
	struct inode *inode = d_inode(dentry);
	struct shfl_string *path;
	u32 flags;
	int err;

	if (S_ISDIR(inode->i_mode))
	flags = SHFL_REMOVE_DIR;
	else
	flags = SHFL_REMOVE_FILE;

	if (S_ISLNK(inode->i_mode))
	flags \|= SHFL_REMOVE_SYMLINK;

	path = vboxsf_path_from_dentry(sbi, dentry);
	if (IS_ERR(path))
	return PTR_ERR(path);

	err = vboxsf_remove(sbi->root, path, flags);
	__putname(path);
	if (err)
	return err;

	/* parent directory access/change time changed */
	sf_parent_i->force_restat = 1;

	return 0;
	}

	static int vboxsf_dir_rename(struct user_namespace *mnt_userns,
	struct inode *old_parent,
	struct dentry *old_dentry,
	struct inode *new_parent,
	struct dentry *new_dentry,
	unsigned int flags)
	{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(old_parent->i_sb);
	struct vboxsf_inode *sf_old_parent_i = VBOXSF_I(old_parent);
	struct vboxsf_inode *sf_new_parent_i = VBOXSF_I(new_parent);
	u32 shfl_flags = SHFL_RENAME_FILE \| SHFL_RENAME_REPLACE_IF_EXISTS;
	struct shfl_string old_path, new_path;
	int err;

	if (flags)
	return -EINVAL;

	old_path = vboxsf_path_from_dentry(sbi, old_dentry);
	if (IS_ERR(old_path))
	return PTR_ERR(old_path);

	new_path = vboxsf_path_from_dentry(sbi, new_dentry);
	if (IS_ERR(new_path)) {
	err = PTR_ERR(new_path);
	goto err_put_old_path;
	}

	if (d_inode(old_dentry)->i_mode & S_IFDIR)
	shfl_flags = 0;

	err = vboxsf_rename(sbi->root, old_path, new_path, shfl_flags);
	if (err == 0) {
	/* parent directories access/change time changed */
	sf_new_parent_i->force_restat = 1;
	sf_old_parent_i->force_restat = 1;
	}

	__putname(new_path);
	err_put_old_path:
	__putname(old_path);
	return err;
	}

	static int vboxsf_dir_symlink(struct user_namespace *mnt_userns,
	struct inode parent, struct dentry dentry,
	const char *symname)
	{
	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
	int symname_size = strlen(symname) + 1;
	struct shfl_string path, ssymname;
	struct shfl_fsobjinfo info;
	int err;

	path = vboxsf_path_from_dentry(sbi, dentry);
	if (IS_ERR(path))
	return PTR_ERR(path);

	ssymname = kmalloc(SHFLSTRING_HEADER_SIZE + symname_size, GFP_KERNEL);
	if (!ssymname) {
	__putname(path);
	return -ENOMEM;
	}
	ssymname->length = symname_size - 1;
	ssymname->size = symname_size;
	memcpy(ssymname->string.utf8, symname, symname_size);

	err = vboxsf_symlink(sbi->root, path, ssymname, &info);
	kfree(ssymname);
	__putname(path);
	if (err) {
	/* -EROFS means symlinks are note support -> -EPERM */
	return (err == -EROFS) ? -EPERM : err;
	}

	err = vboxsf_dir_instantiate(parent, dentry, &info);
	if (err)
	return err;

	/* parent directory access/change time changed */
	sf_parent_i->force_restat = 1;
	return 0;
	}

	const struct inode_operations vboxsf_dir_iops = {
	.lookup = vboxsf_dir_lookup,
	.create = vboxsf_dir_mkfile,
	.mkdir = vboxsf_dir_mkdir,
	.rmdir = vboxsf_dir_unlink,
	.unlink = vboxsf_dir_unlink,
	.rename = vboxsf_dir_rename,
	.symlink = vboxsf_dir_symlink,
	.getattr = vboxsf_getattr,
	.setattr = vboxsf_setattr,
	};