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* [PATCH v2 0/1] fs: Add VirtualBox guest shared folder (vboxsf) support
@ 2018-01-15 17:51 Hans de Goede
  2018-01-15 17:51 ` [PATCH v2] " Hans de Goede
  0 siblings, 1 reply; 11+ messages in thread
From: Hans de Goede @ 2018-01-15 17:51 UTC (permalink / raw)
  To: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer, Alexander Viro
  Cc: Hans de Goede, Larry Finger, Christoph Hellwig, linux-kernel,
	linux-fsdevel

Hi All,

Now that the vboxguest driver which the vboxsf (guest shared folder)
fs driver depends on is queued for merging into 4.16 in char-misc-next,
all the dependencies for the vboxsf are in place.

So here is a v2 of my initial vboxsf, addressing all of the remark from
Christoph Hellwig about v1:
 -Removed various unused wrapper functions
 -Don't use i_private, instead defined alloc_inode and destroy_inode
  methods and use container_of.
 -Drop obsolete comment referencing people to
  http://www.atnf.csiro.au/people/rgooch/linux/vfs.txt
 -move the single symlink op of from lnkops.c to file.c

As well as bunch of other cleanups:
 -Use SPDX license headers
 -Replace SHFLROOT / SHFLHANDLE defines with normal types
 -Removed unnecessary S_ISREG checks
 -Got rid of bounce_buffer in regops, instead add a "user" flag to 
  vboxsf_read / vboxsf_write, re-using the existing __user address support
  in the vboxguest module
 -Make vboxsf_wrappers return regular linux errno values
 -Use i_size_write to update size on writing
 -Convert doxygen style comments to kerneldoc style comments

Please review.

Regards,

Hans

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 17:51 [PATCH v2 0/1] fs: Add VirtualBox guest shared folder (vboxsf) support Hans de Goede
@ 2018-01-15 17:51 ` Hans de Goede
  2018-01-15 17:55   ` Christoph Hellwig
                     ` (2 more replies)
  0 siblings, 3 replies; 11+ messages in thread
From: Hans de Goede @ 2018-01-15 17:51 UTC (permalink / raw)
  To: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer, Alexander Viro
  Cc: Hans de Goede, Larry Finger, Christoph Hellwig, linux-kernel,
	linux-fsdevel

VirtualBox hosts can share folders with guests, this commit adds a
VFS driver implementing the Linux-guest side of this, allowing folders
exported by the host to be mounted under Linux.

This driver depends on the guest <-> host IPC functions exported by
the vboxguest driver.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 fs/Kconfig                     |   1 +
 fs/Makefile                    |   1 +
 fs/vboxsf/Kconfig              |   9 +
 fs/vboxsf/Makefile             |   3 +
 fs/vboxsf/dir.c                | 648 +++++++++++++++++++++++++++++
 fs/vboxsf/file.c               | 416 +++++++++++++++++++
 fs/vboxsf/shfl_hostintf.h      | 919 +++++++++++++++++++++++++++++++++++++++++
 fs/vboxsf/super.c              | 430 +++++++++++++++++++
 fs/vboxsf/utils.c              | 589 ++++++++++++++++++++++++++
 fs/vboxsf/vboxsf_wrappers.c    | 365 ++++++++++++++++
 fs/vboxsf/vboxsf_wrappers.h    |  46 +++
 fs/vboxsf/vfsmod.h             | 104 +++++
 include/uapi/linux/vbsfmount.h |  62 +++
 13 files changed, 3593 insertions(+)
 create mode 100644 fs/vboxsf/Kconfig
 create mode 100644 fs/vboxsf/Makefile
 create mode 100644 fs/vboxsf/dir.c
 create mode 100644 fs/vboxsf/file.c
 create mode 100644 fs/vboxsf/shfl_hostintf.h
 create mode 100644 fs/vboxsf/super.c
 create mode 100644 fs/vboxsf/utils.c
 create mode 100644 fs/vboxsf/vboxsf_wrappers.c
 create mode 100644 fs/vboxsf/vboxsf_wrappers.h
 create mode 100644 fs/vboxsf/vfsmod.h
 create mode 100644 include/uapi/linux/vbsfmount.h

diff --git a/fs/Kconfig b/fs/Kconfig
index 7aee6d699fd6..7f80ad1cf591 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -248,6 +248,7 @@ source "fs/pstore/Kconfig"
 source "fs/sysv/Kconfig"
 source "fs/ufs/Kconfig"
 source "fs/exofs/Kconfig"
+source "fs/vboxsf/Kconfig"
 
 endif # MISC_FILESYSTEMS
 
diff --git a/fs/Makefile b/fs/Makefile
index ef772f1eaff8..3057830f112a 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -129,3 +129,4 @@ obj-y				+= exofs/ # Multiple modules
 obj-$(CONFIG_CEPH_FS)		+= ceph/
 obj-$(CONFIG_PSTORE)		+= pstore/
 obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
+obj-$(CONFIG_VBOXSF_FS)		+= vboxsf/
diff --git a/fs/vboxsf/Kconfig b/fs/vboxsf/Kconfig
new file mode 100644
index 000000000000..620e2232969c
--- /dev/null
+++ b/fs/vboxsf/Kconfig
@@ -0,0 +1,9 @@
+config VBOXSF_FS
+	tristate "VirtualBox guest shared folder (vboxsf) support"
+	depends on VBOXGUEST
+	help
+	  VirtualBox hosts can share folders with guests, this driver
+	  implements the Linux-guest side of this allowing folders exported
+	  by the host to be mounted under Linux.
+
+	  If you want to use shared folders in VirtualBox guests, answer Y or M.
diff --git a/fs/vboxsf/Makefile b/fs/vboxsf/Makefile
new file mode 100644
index 000000000000..fcbd488f9eec
--- /dev/null
+++ b/fs/vboxsf/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_VBOXSF_FS) += vboxsf.o
+
+vboxsf-objs := dir.o file.o utils.o vboxsf_wrappers.o super.o
diff --git a/fs/vboxsf/dir.c b/fs/vboxsf/dir.c
new file mode 100644
index 000000000000..7650f92041f7
--- /dev/null
+++ b/fs/vboxsf/dir.c
@@ -0,0 +1,648 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VirtualBox Guest Shared Folders support: Directory inode and file operations
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#include <linux/namei.h>
+#include <linux/vbox_utils.h>
+#include "vfsmod.h"
+
+/**
+ * Open a directory. Read the complete content into a buffer.
+ * Return: 0 or negative errno value.
+ * @inode	inode
+ * @file	file
+ */
+static int sf_dir_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_dir_info *sf_d;
+	struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
+	struct shfl_createparms params = {};
+
+	if (file->private_data)
+		return 0;
+
+	sf_d = sf_dir_info_alloc();
+	if (!sf_d)
+		return -ENOMEM;
+
+	params.handle = SHFL_HANDLE_NIL;
+	params.create_flags = 0
+	    | SHFL_CF_DIRECTORY
+	    | SHFL_CF_ACT_OPEN_IF_EXISTS
+	    | SHFL_CF_ACT_FAIL_IF_NEW | SHFL_CF_ACCESS_READ;
+
+	err = vboxsf_create(sf_g->root, sf_i->path, &params);
+	if (err == 0) {
+		if (params.result == SHFL_FILE_EXISTS) {
+			err = sf_dir_read_all(sf_g, sf_i, sf_d, params.handle);
+			if (!err)
+				file->private_data = sf_d;
+		} else
+			err = -ENOENT;
+
+		vboxsf_close(sf_g->root, params.handle);
+	}
+
+	if (err)
+		sf_dir_info_free(sf_d);
+
+	return err;
+}
+
+/**
+ * This is called when reference count of [file] goes to zero. Notify
+ * the host that it can free whatever is associated with this directory
+ * and deallocate our own internal buffers
+ * Return: 0 or negative errno value.
+ * @inode	inode
+ * @file	file
+ */
+static int sf_dir_release(struct inode *inode, struct file *file)
+{
+	if (file->private_data)
+		sf_dir_info_free(file->private_data);
+
+	return 0;
+}
+
+/**
+ * Translate RTFMODE into DT_xxx (in conjunction to rtDirType())
+ * Return: d_type
+ * @mode	file mode
+ */
+static int sf_get_d_type(u32 mode)
+{
+	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;
+}
+
+/**
+ * Extract element ([dir]->f_pos) from the directory [dir] into [d_name].
+ * Return: 0 or negative errno value.
+ * @dir		Directory to get element at f_pos from
+ * @d_name	Buffer in which to return element name
+ * @d_type	Buffer in which to return element file-type
+ */
+static int sf_getdent(struct file *dir, char d_name[NAME_MAX], int *d_type)
+{
+	loff_t cur;
+	struct sf_glob_info *sf_g;
+	struct sf_dir_info *sf_d;
+	struct sf_inode_info *sf_i;
+	struct inode *inode;
+	struct list_head *pos, *list;
+
+	inode = GET_F_DENTRY(dir)->d_inode;
+	sf_i = GET_INODE_INFO(inode);
+	sf_g = GET_GLOB_INFO(inode->i_sb);
+	sf_d = dir->private_data;
+
+	if (sf_i->force_reread) {
+		int err;
+		struct shfl_createparms params = {};
+
+		params.handle = SHFL_HANDLE_NIL;
+		params.create_flags = 0
+		    | SHFL_CF_DIRECTORY
+		    | SHFL_CF_ACT_OPEN_IF_EXISTS
+		    | SHFL_CF_ACT_FAIL_IF_NEW | SHFL_CF_ACCESS_READ;
+
+		err = vboxsf_create(sf_g->root, sf_i->path, &params);
+		if (err)
+			return err;
+
+		if (params.result != SHFL_FILE_EXISTS) {
+			sf_dir_info_free(sf_d);
+			return -ENOENT;
+		}
+
+		sf_dir_info_empty(sf_d);
+		err = sf_dir_read_all(sf_g, sf_i, sf_d, params.handle);
+		vboxsf_close(sf_g->root, params.handle);
+		if (err)
+			return err;
+
+		sf_i->force_reread = 0;
+	}
+
+	cur = 0;
+	list = &sf_d->info_list;
+	list_for_each(pos, list) {
+		struct sf_dir_buf *b;
+		struct shfl_dirinfo *info;
+		loff_t i;
+
+		b = list_entry(pos, struct sf_dir_buf, head);
+		if (dir->f_pos >= cur + b->entries) {
+			cur += b->entries;
+			continue;
+		}
+
+		for (i = 0, info = b->buf; i < dir->f_pos - cur; ++i) {
+			size_t size;
+
+			size = offsetof(struct shfl_dirinfo, name.string) +
+			       info->name.size;
+			info = (struct shfl_dirinfo *)((uintptr_t) info + size);
+		}
+
+		*d_type = sf_get_d_type(info->info.attr.mode);
+
+		return sf_nlscpy(sf_g, d_name, NAME_MAX,
+				 info->name.string.utf8, info->name.length);
+	}
+
+	return 1;
+}
+
+/**
+ * This is called when vfs wants to populate internal buffers with
+ * directory [dir]s contents. [opaque] is an argument to the
+ * [filldir]. [filldir] magically modifies it's argument - [opaque]
+ * and takes following additional arguments (which i in turn get from
+ * the host via sf_getdent):
+ *
+ * name : name of the entry (i must also supply it's length huh?)
+ * type : type of the entry (FILE | DIR | etc) (i ellect to use DT_UNKNOWN)
+ * pos : position/index of the entry
+ * ino : inode number of the entry (i fake those)
+ *
+ * [dir] contains:
+ * f_pos : cursor into the directory listing
+ * private_data : mean of communication with the host side
+ *
+ * Extract elements from the directory listing (incrementing f_pos
+ * along the way) and feed them to [filldir] until:
+ *
+ * a. there are no more entries (i.e. sf_getdent set done to 1)
+ * b. failure to compute fake inode number
+ * c. filldir returns an error (see comment on that)
+ * Return: 0 or negative errno value.
+ * @dir		Directory to read
+ * @ctx		Directory context in which to store read elements
+ */
+static int sf_dir_iterate(struct file *dir, struct dir_context *ctx)
+{
+	for (;;) {
+		int err;
+		ino_t fake_ino;
+		loff_t sanity;
+		char d_name[NAME_MAX];
+		int d_type = DT_UNKNOWN;
+
+		err = sf_getdent(dir, d_name, &d_type);
+		switch (err) {
+		case 1:
+			return 0;
+
+		case 0:
+			break;
+
+		case -1:
+		default:
+			/* skip erroneous entry and proceed */
+			dir->f_pos += 1;
+			ctx->pos += 1;
+			continue;
+		}
+
+		/* d_name now contains a valid entry name */
+		sanity = ctx->pos + 0xbeef;
+		fake_ino = sanity;
+		/*
+		 * On 32 bit systems pos is 64 signed, while ino is 32 bit
+		 * unsigned so fake_ino may overflow, check for this.
+		 */
+		if (sanity - fake_ino) {
+			vbg_err("vboxsf: can not compute ino\n");
+			return -EINVAL;
+		}
+		if (!dir_emit(ctx, d_name, strlen(d_name), fake_ino, d_type))
+			return 0;
+
+		dir->f_pos += 1;
+		ctx->pos += 1;
+	}
+}
+
+const struct file_operations sf_dir_fops = {
+	.open = sf_dir_open,
+	.iterate = sf_dir_iterate,
+	.release = sf_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 [sf_inode_revalidate].
+ */
+static int sf_dentry_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	if (sf_inode_revalidate(dentry))
+		return 0;
+
+	return 1;
+}
+
+static const struct dentry_operations sf_dentry_ops = {
+	.d_revalidate = sf_dentry_revalidate
+};
+
+/* iops */
+
+/**
+ * This is called when vfs failed to locate dentry in the cache. The
+ * job of this function is to allocate inode and link it to dentry.
+ * [dentry] contains the name to be looked in the [parent] directory.
+ * Failure to locate the name is not a "hard" error, in this case NULL
+ * inode is added to [dentry] and vfs should proceed trying to create
+ * the entry via other means. NULL(or "positive" pointer) ought to be
+ * returned in case of success and "negative" pointer on error
+ * Return: NULL on success, ERR_PTR on failure.
+ * @parent	inode of the dentry parent-directory
+ * @dentry	dentry to populate
+ * @flags	flags
+ */
+static struct dentry *sf_lookup(struct inode *parent, struct dentry *dentry,
+				unsigned int flags)
+{
+	struct shfl_fsobjinfo fsinfo;
+	struct sf_inode_info *sf_i;
+	struct sf_glob_info *sf_g;
+	struct shfl_string *path;
+	struct inode *inode;
+	ino_t ino;
+	int err;
+
+	sf_g = GET_GLOB_INFO(parent->i_sb);
+	sf_i = GET_INODE_INFO(parent);
+
+	err = sf_path_from_dentry(__func__, sf_g, sf_i, dentry, &path);
+	if (err)
+		return ERR_PTR(err);
+
+	err = sf_stat(__func__, sf_g, path, &fsinfo, 1);
+	if (err) {
+		kfree(path);
+		if (err != -ENOENT)
+			return ERR_PTR(err);
+		/*
+		 * -ENOENT: add NULL inode to dentry so it later can
+		 * be created via call to create/mkdir/open
+		 */
+		inode = NULL;
+	} else {
+		ino = iunique(parent->i_sb, 1);
+		inode = iget_locked(parent->i_sb, ino);
+		if (!inode) {
+			kfree(path);
+			return ERR_PTR(-ENOMEM);
+		}
+
+		GET_INODE_INFO(inode)->path = path;
+		sf_init_inode(sf_g, inode, &fsinfo);
+
+		unlock_new_inode(inode);
+	}
+
+	dentry->d_time = jiffies;
+	d_set_d_op(dentry, &sf_dentry_ops);
+	d_add(dentry, inode);
+	return NULL;
+}
+
+/**
+ * This should allocate memory for sf_inode_info, compute a unique inode
+ * number, get an inode from vfs, initialize inode info, instantiate
+ * dentry.
+ * Return: 0 or negative errno value.
+ * @parent	inode entry of the directory
+ * @dentry	directory cache entry
+ * @path	path name
+ * @info	file information
+ * @handle	handle
+ */
+static int sf_instantiate(struct inode *parent, struct dentry *dentry,
+			  struct shfl_string *path, struct shfl_fsobjinfo *info,
+			  u64 handle)
+{
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(parent->i_sb);
+	struct sf_inode_info *sf_i;
+	struct inode *inode;
+	ino_t ino;
+
+	ino = iunique(parent->i_sb, 1);
+	inode = iget_locked(parent->i_sb, ino);
+	if (!inode)
+		return -ENOMEM;
+
+	sf_i = GET_INODE_INFO(inode);
+	sf_i->path = path;
+	sf_i->force_restat = 1;
+	sf_i->handle = handle;
+	sf_init_inode(sf_g, inode, info);
+
+	d_instantiate(dentry, inode);
+	unlock_new_inode(inode);
+
+	return 0;
+}
+
+/**
+ * Create a new regular file / directory.
+ * Return: 0 or negative errno value.
+ * @parent	inode of the directory
+ * @dentry	directory cache entry
+ * @mode	file mode
+ * @is_dir	true if directory, false otherwise
+ */
+static int sf_create_aux(struct inode *parent, struct dentry *dentry,
+			 umode_t mode, int is_dir)
+{
+	int err;
+	struct shfl_createparms params = {};
+	struct shfl_string *path;
+	struct sf_inode_info *sf_i = GET_INODE_INFO(parent);
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(parent->i_sb);
+
+	err = sf_path_from_dentry(__func__, sf_g, sf_i, dentry, &path);
+	if (err)
+		return err;
+
+	params.handle = SHFL_HANDLE_NIL;
+	params.create_flags = 0
+	    | 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 = 0
+	    | (is_dir ? SHFL_TYPE_DIRECTORY : SHFL_TYPE_FILE)
+	    | (mode & 0777);
+	params.info.attr.additional = SHFLFSOBJATTRADD_NOTHING;
+
+	err = vboxsf_create(sf_g->root, path, &params);
+	if (err)
+		goto free_path;
+
+	if (params.result != SHFL_FILE_CREATED) {
+		err = -EPERM;
+		goto free_path;
+	}
+
+	err = sf_instantiate(parent, dentry, path, &params.info,
+			     is_dir ? SHFL_HANDLE_NIL : params.handle);
+	if (err)
+		goto close_handle;
+
+	/*
+	 * Don't close this handle right now. We assume that the same file is
+	 * opened with sf_reg_open() and later closed with sf_reg_close(). Save
+	 * the handle in between. Does not apply to directories. True?
+	 */
+	if (is_dir)
+		vboxsf_close(sf_g->root, params.handle);
+
+	sf_i->force_restat = 1;
+	return 0;
+
+close_handle:
+	vboxsf_close(sf_g->root, params.handle);
+
+free_path:
+	kfree(path);
+	return err;
+}
+
+/**
+ * Create a new regular file.
+ * Return: 0 or negative errno value.
+ * @parent	inode of the directory
+ * @dentry	directory cache entry
+ * @mode	file mode
+ * @excl	Possible O_EXCL...
+ */
+static int sf_create(struct inode *parent, struct dentry *dentry, umode_t mode,
+		     bool excl)
+{
+	return sf_create_aux(parent, dentry, mode, 0);
+}
+
+/**
+ * Create a new directory.
+ * Return: 0 or negative errno value.
+ * @parent	inode of the directory
+ * @dentry	directory cache entry
+ * @mode	file mode
+ */
+static int sf_mkdir(struct inode *parent, struct dentry *dentry, umode_t mode)
+{
+	return sf_create_aux(parent, dentry, mode, 1);
+}
+
+/**
+ * Remove a regular file / directory.
+ * Return: 0 or negative errno value.
+ * @parent	inode of the directory
+ * @dentry	directory cache entry
+ * @is_dir	true if directory, false otherwise
+ */
+static int sf_unlink_aux(struct inode *parent, struct dentry *dentry,
+			 int is_dir)
+{
+	int err;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(parent->i_sb);
+	struct sf_inode_info *sf_i = GET_INODE_INFO(parent);
+	struct shfl_string *path;
+	uint32_t flags;
+
+	err = sf_path_from_dentry(__func__, sf_g, sf_i, dentry, &path);
+	if (err)
+		return err;
+
+	flags = is_dir ? SHFL_REMOVE_DIR : SHFL_REMOVE_FILE;
+	if (dentry
+	    && dentry->d_inode
+	    && ((dentry->d_inode->i_mode & S_IFLNK) == S_IFLNK))
+		flags |= SHFL_REMOVE_SYMLINK;
+
+	err = vboxsf_remove(sf_g->root, path, flags);
+	if (err)
+		goto free_path;
+
+	/* directory access/change time changed */
+	sf_i->force_restat = 1;
+	/* directory content changed */
+	sf_i->force_reread = 1;
+
+free_path:
+	kfree(path);
+	return err;
+}
+
+/**
+ * Remove a regular file.
+ * Return: 0 or negative errno value.
+ * @parent	inode of the directory
+ * @dentry	directory cache entry
+ */
+static int sf_unlink(struct inode *parent, struct dentry *dentry)
+{
+	return sf_unlink_aux(parent, dentry, 0);
+}
+
+/**
+ * Remove a directory.
+ * Return: 0 or negative errno value.
+ * @parent	inode of the directory
+ * @dentry	directory cache entry
+ */
+static int sf_rmdir(struct inode *parent, struct dentry *dentry)
+{
+	return sf_unlink_aux(parent, dentry, 1);
+}
+
+/**
+ * Rename a regular file / directory.
+ * Return: 0 or negative errno value.
+ * @old_parent	inode of the old parent directory
+ * @old_dentry	old directory cache entry
+ * @new_parent	inode of the new parent directory
+ * @new_dentry	new directory cache entry
+ * @flags	flags
+ */
+static int sf_rename(struct inode *old_parent, struct dentry *old_dentry,
+		     struct inode *new_parent, struct dentry *new_dentry,
+		     unsigned int flags)
+{
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(old_parent->i_sb);
+	u32 shfl_flags = SHFL_RENAME_FILE | SHFL_RENAME_REPLACE_IF_EXISTS;
+	struct sf_inode_info *sf_old_i = GET_INODE_INFO(old_parent);
+	struct sf_inode_info *sf_new_i = GET_INODE_INFO(new_parent);
+	/*
+	 * As we save the relative path inside the inode structure,
+	 * we need to change this if the rename is successful.
+	 */
+	struct sf_inode_info *sf_file_i = GET_INODE_INFO(old_dentry->d_inode);
+	struct shfl_string *path;
+	int err;
+
+	if (flags)
+		return -EINVAL;
+
+	if (sf_g != GET_GLOB_INFO(new_parent->i_sb))
+		return -EINVAL;
+
+	err = sf_path_from_dentry(__func__, sf_g, sf_new_i, new_dentry, &path);
+	if (err)
+		return err;
+
+	if (old_dentry->d_inode->i_mode & S_IFDIR)
+		shfl_flags = 0;
+
+	err = vboxsf_rename(sf_g->root, sf_file_i->path, path, shfl_flags);
+	if (err == 0) {
+		/* Set the new relative path in the inode. */
+		kfree(sf_file_i->path);
+		sf_file_i->path = path;
+		sf_new_i->force_restat = 1;
+		sf_old_i->force_restat = 1;
+	} else {
+		kfree(path);
+	}
+
+	return err;
+}
+
+static int sf_symlink(struct inode *parent, struct dentry *dentry,
+		      const char *symname)
+{
+	int err;
+	struct sf_inode_info *sf_i;
+	struct sf_glob_info *sf_g;
+	struct shfl_string *path, *ssymname;
+	struct shfl_fsobjinfo info;
+	int symname_len = strlen(symname) + 1;
+
+	sf_g = GET_GLOB_INFO(parent->i_sb);
+	sf_i = GET_INODE_INFO(parent);
+
+	err = sf_path_from_dentry(__func__, sf_g, sf_i, dentry, &path);
+	if (err)
+		return err;
+
+	ssymname = kmalloc(SHFLSTRING_HEADER_SIZE + symname_len, GFP_KERNEL);
+	if (!ssymname) {
+		err = -ENOMEM;
+		goto free_path;
+	}
+	ssymname->length = symname_len - 1;
+	ssymname->size = symname_len;
+	memcpy(ssymname->string.utf8, symname, symname_len);
+
+	err = vboxsf_symlink(sf_g->root, path, ssymname, &info);
+	kfree(ssymname);
+
+	if (err)
+		goto free_path;
+
+	err = sf_instantiate(parent, dentry, path, &info, SHFL_HANDLE_NIL);
+	if (err)
+		goto free_path;
+
+	sf_i->force_restat = 1;
+	return 0;
+
+free_path:
+	kfree(path);
+	return err;
+}
+
+const struct inode_operations sf_dir_iops = {
+	.lookup = sf_lookup,
+	.create = sf_create,
+	.mkdir = sf_mkdir,
+	.rmdir = sf_rmdir,
+	.unlink = sf_unlink,
+	.rename = sf_rename,
+	.getattr = sf_getattr,
+	.setattr = sf_setattr,
+	.symlink = sf_symlink
+};
diff --git a/fs/vboxsf/file.c b/fs/vboxsf/file.c
new file mode 100644
index 000000000000..8e085a28cf91
--- /dev/null
+++ b/fs/vboxsf/file.c
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VirtualBox Guest Shared Folders support: Regular file inode and file ops.
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#include <linux/sizes.h>
+#include "vfsmod.h"
+
+/**
+ * Read from a regular file.
+ * Return: The number of bytes read on success, negative errno value otherwise
+ * @file	the file
+ * @buf		the buffer
+ * @size	length of the buffer
+ * @off		offset within the file
+ */
+static ssize_t sf_reg_read(struct file *file, char *buf, size_t size,
+			   loff_t *off)
+{
+	struct inode *inode = GET_F_DENTRY(file)->d_inode;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_reg_info *sf_r = file->private_data;
+	u64 pos = *off;
+	u32 nread;
+	int err;
+
+	if (!size)
+		return 0;
+
+	if (size > SHFL_MAX_RW_COUNT)
+		nread = SHFL_MAX_RW_COUNT;
+	else
+		nread = size;
+
+	err = vboxsf_read(sf_g->root, sf_r->handle, pos, &nread, buf, true);
+	if (err)
+		return err;
+
+	*off += nread;
+	return nread;
+}
+
+/**
+ * Write to a regular file.
+ * Return: The number of bytes written on success, negative errno val otherwise
+ * @file	the file
+ * @buf		the buffer
+ * @size	length of the buffer
+ * @off		offset within the file
+ */
+static ssize_t sf_reg_write(struct file *file, const char *buf, size_t size,
+			    loff_t *off)
+{
+	struct inode *inode = GET_F_DENTRY(file)->d_inode;
+	struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_reg_info *sf_r = file->private_data;
+	u32 nwritten;
+	u64 pos;
+	int err;
+
+	pos = *off;
+	if (file->f_flags & O_APPEND) {
+		pos = inode->i_size;
+		*off = pos;
+	}
+
+	if (!size)
+		return 0;
+
+	if (size > SHFL_MAX_RW_COUNT)
+		nwritten = SHFL_MAX_RW_COUNT;
+	else
+		nwritten = size;
+
+	err = vboxsf_write(sf_g->root, sf_r->handle, pos, &nwritten, buf, true);
+	if (err)
+		return err;
+
+	*off += nwritten;
+	if (*off > inode->i_size)
+		i_size_write(inode, *off);
+
+	sf_i->force_restat = 1;
+	return nwritten;
+}
+
+/**
+ * Open a regular file.
+ * Return: 0 or negative errno value.
+ * @inode	inode
+ * @file	file
+ */
+static int sf_reg_open(struct inode *inode, struct file *file)
+{
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
+	struct sf_reg_info *sf_r;
+	struct shfl_createparms params = {};
+	int err;
+
+	sf_r = kmalloc(sizeof(*sf_r), GFP_KERNEL);
+	if (!sf_r)
+		return -ENOMEM;
+
+	/* Already open? */
+	if (sf_i->handle != SHFL_HANDLE_NIL) {
+		/*
+		 * This inode was created with sf_create_aux(). Check the
+		 * create_flags: O_CREAT, O_TRUNC: inherent true (file was
+		 * just created).
+		 * Not sure about the access flags (SHFL_CF_ACCESS_*).
+		 */
+		sf_i->force_restat = 1;
+		sf_r->handle = sf_i->handle;
+		sf_i->handle = SHFL_HANDLE_NIL;
+		sf_i->file = file;
+		file->private_data = sf_r;
+		return 0;
+	}
+
+	params.handle = SHFL_HANDLE_NIL;
+
+	/*
+	 * We check the value of params.handle afterwards to find out if
+	 * the call succeeded or failed, as the API does not seem to cleanly
+	 * distinguish error and informational messages.
+	 *
+	 * Furthermore, we must set params.handle to SHFL_HANDLE_NIL to
+	 * make the shared folders host service use our mode parameter.
+	 */
+	if (file->f_flags & O_CREAT) {
+		params.create_flags |= SHFL_CF_ACT_CREATE_IF_NEW;
+		/*
+		 * We ignore O_EXCL, as the Linux kernel seems to call create
+		 * beforehand itself, so O_EXCL should always fail.
+		 */
+		if (file->f_flags & O_TRUNC)
+			params.create_flags |= SHFL_CF_ACT_OVERWRITE_IF_EXISTS;
+		else
+			params.create_flags |= SHFL_CF_ACT_OPEN_IF_EXISTS;
+	} else {
+		params.create_flags |= SHFL_CF_ACT_FAIL_IF_NEW;
+		if (file->f_flags & O_TRUNC)
+			params.create_flags |= SHFL_CF_ACT_OVERWRITE_IF_EXISTS;
+	}
+
+	switch (file->f_flags & O_ACCMODE) {
+	case O_RDONLY:
+		params.create_flags |= SHFL_CF_ACCESS_READ;
+		break;
+
+	case O_WRONLY:
+		params.create_flags |= SHFL_CF_ACCESS_WRITE;
+		break;
+
+	case O_RDWR:
+		params.create_flags |= SHFL_CF_ACCESS_READWRITE;
+		break;
+
+	default:
+		WARN_ON(1);
+	}
+
+	if (file->f_flags & O_APPEND)
+		params.create_flags |= SHFL_CF_ACCESS_APPEND;
+
+	params.info.attr.mode = inode->i_mode;
+	err = vboxsf_create(sf_g->root, sf_i->path, &params);
+	if (err == 0 && params.handle == SHFL_HANDLE_NIL)
+		err = (params.result == SHFL_FILE_EXISTS) ? -EEXIST : -ENOENT;
+	if (err) {
+		kfree(sf_r);
+		return err;
+	}
+
+	sf_i->force_restat = 1;
+	sf_r->handle = params.handle;
+	sf_i->file = file;
+	file->private_data = sf_r;
+	return 0;
+}
+
+/**
+ * Close a regular file.
+ * Return: 0 or negative errno value.
+ * @inode	inode
+ * @file	file
+ */
+static int sf_reg_release(struct inode *inode, struct file *file)
+{
+	struct sf_reg_info *sf_r;
+	struct sf_glob_info *sf_g;
+	struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
+
+	sf_g = GET_GLOB_INFO(inode->i_sb);
+	sf_r = file->private_data;
+
+	filemap_write_and_wait(inode->i_mapping);
+
+	vboxsf_close(sf_g->root, sf_r->handle);
+
+	kfree(sf_r);
+	sf_i->file = NULL;
+	sf_i->handle = SHFL_HANDLE_NIL;
+	file->private_data = NULL;
+	return 0;
+}
+
+static int sf_reg_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct file *file = vma->vm_file;
+	struct inode *inode = GET_F_DENTRY(file)->d_inode;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_reg_info *sf_r = file->private_data;
+	u32 nread = PAGE_SIZE;
+	struct page *page;
+	u64 off;
+	u8 *buf;
+	int err;
+
+	if (vmf->pgoff > vma->vm_end)
+		return VM_FAULT_SIGBUS;
+
+	/* No GFP_HIGHUSER, the page must have a valid virtual address. */
+	page = alloc_page(GFP_USER);
+	if (!page)
+		return VM_FAULT_OOM;
+
+	buf = kmap(page);
+	off = (vmf->pgoff << PAGE_SHIFT);
+	err = vboxsf_read(sf_g->root, sf_r->handle, off, &nread, buf, false);
+	if (err) {
+		kunmap(page);
+		put_page(page);
+		return VM_FAULT_SIGBUS;
+	}
+
+	if (!nread)
+		clear_user_page(page_address(page), vmf->pgoff, page);
+	else
+		memset(buf + nread, 0, PAGE_SIZE - nread);
+
+	flush_dcache_page(page);
+	kunmap(page);
+	vmf->page = page;
+	return 0;
+}
+
+static const struct vm_operations_struct sf_vma_ops = {
+	.fault = sf_reg_fault
+};
+
+static int sf_reg_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	if (vma->vm_flags & VM_SHARED)
+		return -EINVAL;
+
+	vma->vm_ops = &sf_vma_ops;
+	return 0;
+}
+
+const struct file_operations sf_reg_fops = {
+	.read = sf_reg_read,
+	.open = sf_reg_open,
+	.write = sf_reg_write,
+	.release = sf_reg_release,
+	.mmap = sf_reg_mmap,
+	.splice_read = generic_file_splice_read,
+	.read_iter = generic_file_read_iter,
+	.write_iter = generic_file_write_iter,
+	.fsync = noop_fsync,
+	.llseek = generic_file_llseek,
+};
+
+const struct inode_operations sf_reg_iops = {
+	.getattr = sf_getattr,
+	.setattr = sf_setattr
+};
+
+static int sf_readpage(struct file *file, struct page *page)
+{
+	struct inode *inode = GET_F_DENTRY(file)->d_inode;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_reg_info *sf_r = file->private_data;
+	u64 off = page_offset(page);
+	u32 nread = PAGE_SIZE;
+	u8 *buf;
+	int err;
+
+	buf = kmap(page);
+
+	err = vboxsf_read(sf_g->root, sf_r->handle, off, &nread, buf, false);
+	if (err == 0) {
+		memset(&buf[nread], 0, PAGE_SIZE - nread);
+		flush_dcache_page(page);
+		SetPageUptodate(page);
+	} else {
+		SetPageError(page);
+	}
+
+	kunmap(page);
+	unlock_page(page);
+	return err;
+}
+
+static int sf_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
+	struct file *file = sf_i->file;
+	struct sf_reg_info *sf_r = file->private_data;
+	int end_index = inode->i_size >> PAGE_SHIFT;
+	u64 off = page_offset(page);
+	u32 nwritten = PAGE_SIZE;
+	u8 *buf;
+	int err;
+
+	if (page->index >= end_index)
+		nwritten = inode->i_size & (PAGE_SIZE - 1);
+
+	buf = kmap(page);
+	err = vboxsf_write(sf_g->root, sf_r->handle, off, &nwritten, buf, false);
+	kunmap(page);
+
+	if (err == 0)
+		ClearPageError(page);
+	else
+		ClearPageUptodate(page);
+
+	unlock_page(page);
+	return err;
+}
+
+int sf_write_begin(struct file *file, struct address_space *mapping, loff_t pos,
+		   unsigned int len, unsigned int flags, struct page **pagep,
+		   void **fsdata)
+{
+	return simple_write_begin(file, mapping, pos, len, flags, pagep,
+				  fsdata);
+}
+
+int sf_write_end(struct file *file, struct address_space *mapping, loff_t pos,
+		 unsigned int len, unsigned int copied, struct page *page,
+		 void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_reg_info *sf_r = file->private_data;
+	unsigned int from = pos & (PAGE_SIZE - 1);
+	u32 nwritten = len;
+	u8 *buf;
+	int err;
+
+	buf = kmap(page);
+	err = vboxsf_write(sf_g->root, sf_r->handle, pos, &nwritten,
+			  buf + from, false);
+	kunmap(page);
+
+	if (err)
+		goto out;
+
+	if (!PageUptodate(page) && nwritten == PAGE_SIZE)
+		SetPageUptodate(page);
+
+	pos += nwritten;
+	if (pos > inode->i_size)
+		i_size_write(inode, pos);
+
+out:
+	unlock_page(page);
+	put_page(page);
+
+	return err;
+}
+
+const struct address_space_operations sf_reg_aops = {
+	.readpage = sf_readpage,
+	.writepage = sf_writepage,
+	.write_begin = sf_write_begin,
+	.write_end = sf_write_end,
+};
+
+static const char *sf_get_link(struct dentry *dentry, struct inode *inode,
+			       struct delayed_call *done)
+{
+	struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
+	struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
+	char *path;
+	int err;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	path = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!path)
+		return ERR_PTR(-ENOMEM);
+
+	err = vboxsf_readlink(sf_g->root, sf_i->path, PATH_MAX, path);
+	if (err) {
+		kfree(path);
+		return ERR_PTR(err);
+	}
+
+	set_delayed_call(done, kfree_link, path);
+	return path;
+}
+
+const struct inode_operations sf_lnk_iops = {
+	.get_link = sf_get_link
+};
diff --git a/fs/vboxsf/shfl_hostintf.h b/fs/vboxsf/shfl_hostintf.h
new file mode 100644
index 000000000000..8666a5347a0b
--- /dev/null
+++ b/fs/vboxsf/shfl_hostintf.h
@@ -0,0 +1,919 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR CDDL-1.0) */
+/*
+ * VirtualBox Shared Folders: host interface definition.
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#ifndef SHFL_HOSTINTF_H
+#define SHFL_HOSTINTF_H
+
+#include <linux/vbox_vmmdev_types.h>
+
+/* The max in/out buffer size for a FN_READ or FN_WRITE call */
+#define SHFL_MAX_RW_COUNT           (16 * SZ_1M)
+
+/*
+ * Structures shared between guest and the service
+ * can be relocated and use offsets to point to variable
+ * length parts.
+ *
+ * Shared folders protocol works with handles.
+ * Before doing any action on a file system object,
+ * one have to obtain the object handle via a SHFL_FN_CREATE
+ * request. A handle must be closed with SHFL_FN_CLOSE.
+ */
+
+/* Query mappings changes. */
+#define SHFL_FN_QUERY_MAPPINGS      (1)
+/* Query mappings changes. */
+#define SHFL_FN_QUERY_MAP_NAME      (2)
+/* Open/create object. */
+#define SHFL_FN_CREATE              (3)
+/* Close object handle. */
+#define SHFL_FN_CLOSE               (4)
+/* Read object content. */
+#define SHFL_FN_READ                (5)
+/* Write new object content. */
+#define SHFL_FN_WRITE               (6)
+/* Lock/unlock a range in the object. */
+#define SHFL_FN_LOCK                (7)
+/* List object content. */
+#define SHFL_FN_LIST                (8)
+/* Query/set object information. */
+#define SHFL_FN_INFORMATION         (9)
+/* Remove object */
+#define SHFL_FN_REMOVE              (11)
+/* Map folder (legacy) */
+#define SHFL_FN_MAP_FOLDER_OLD      (12)
+/* Unmap folder */
+#define SHFL_FN_UNMAP_FOLDER        (13)
+/* Rename object (possibly moving it to another directory) */
+#define SHFL_FN_RENAME              (14)
+/* Flush file */
+#define SHFL_FN_FLUSH               (15)
+#define SHFL_FN_SET_UTF8            (16)
+#define SHFL_CPARMS_SET_UTF8        0
+/* Map folder */
+#define SHFL_FN_MAP_FOLDER          (17)
+/* Read symlink destination (as of VBox 4.0) */
+#define SHFL_FN_READLINK            (18)
+/* Create symlink (as of VBox 4.0) */
+#define SHFL_FN_SYMLINK             (19)
+/* Ask host to show symlinks (as of VBox 4.0) */
+#define SHFL_FN_SET_SYMLINKS        (20)
+#define SHFL_CPARMS_SET_SYMLINKS    0
+
+/* Root handles for a mapping are of type u32, Root handles are unique. */
+#define SHFL_ROOT_NIL ((u32)~0)
+
+/* Shared folders handle for an opened object are of type u64. */
+#define SHFL_HANDLE_NIL  ((u64)~0LL)
+#define SHFL_HANDLE_ROOT ((u64)0LL)
+
+/* Hardcoded maximum length (in chars) of a shared folder name. */
+#define SHFL_MAX_LEN         (256)
+/* Hardcoded maximum number of shared folder mapping available to the guest. */
+#define SHFL_MAX_MAPPINGS    (64)
+
+/** Shared folder string buffer structure. */
+struct shfl_string {
+	/** Allocated size of the string member in bytes. */
+	u16 size;
+
+	/** Length of string without trailing nul in bytes. */
+	u16 length;
+
+	/** UTF-8 or UTF-16 string. Nul terminated. */
+	union {
+		u8 utf8[1];
+		u16 utf16[1];
+		u16 ucs2[1]; /* misnomer, use utf16. */
+	} string;
+};
+VMMDEV_ASSERT_SIZE(shfl_string, 6);
+
+/* The size of shfl_string w/o the string part. */
+#define SHFLSTRING_HEADER_SIZE  4
+
+/* Calculate size of the string. */
+static inline u32 shfl_string_buf_size(const struct shfl_string *string)
+{
+	return string ? SHFLSTRING_HEADER_SIZE + string->size : 0;
+}
+
+/* Set user id on execution (S_ISUID). */
+#define SHFL_UNIX_ISUID             0004000U
+/* Set group id on execution (S_ISGID). */
+#define SHFL_UNIX_ISGID             0002000U
+/* Sticky bit (S_ISVTX / S_ISTXT). */
+#define SHFL_UNIX_ISTXT             0001000U
+
+/* Owner readable (S_IRUSR). */
+#define SHFL_UNIX_IRUSR             0000400U
+/* Owner writable (S_IWUSR). */
+#define SHFL_UNIX_IWUSR             0000200U
+/* Owner executable (S_IXUSR). */
+#define SHFL_UNIX_IXUSR             0000100U
+
+/* Group readable (S_IRGRP). */
+#define SHFL_UNIX_IRGRP             0000040U
+/* Group writable (S_IWGRP). */
+#define SHFL_UNIX_IWGRP             0000020U
+/* Group executable (S_IXGRP). */
+#define SHFL_UNIX_IXGRP             0000010U
+
+/* Other readable (S_IROTH). */
+#define SHFL_UNIX_IROTH             0000004U
+/* Other writable (S_IWOTH). */
+#define SHFL_UNIX_IWOTH             0000002U
+/* Other executable (S_IXOTH). */
+#define SHFL_UNIX_IXOTH             0000001U
+
+/* Named pipe (fifo) (S_IFIFO). */
+#define SHFL_TYPE_FIFO              0010000U
+/* Character device (S_IFCHR). */
+#define SHFL_TYPE_DEV_CHAR          0020000U
+/* Directory (S_IFDIR). */
+#define SHFL_TYPE_DIRECTORY         0040000U
+/* Block device (S_IFBLK). */
+#define SHFL_TYPE_DEV_BLOCK         0060000U
+/* Regular file (S_IFREG). */
+#define SHFL_TYPE_FILE              0100000U
+/* Symbolic link (S_IFLNK). */
+#define SHFL_TYPE_SYMLINK           0120000U
+/* Socket (S_IFSOCK). */
+#define SHFL_TYPE_SOCKET            0140000U
+/* Whiteout (S_IFWHT). */
+#define SHFL_TYPE_WHITEOUT          0160000U
+/* Type mask (S_IFMT). */
+#define SHFL_TYPE_MASK              0170000U
+
+/* Checks the mode flags indicate a directory (S_ISDIR). */
+#define SHFL_IS_DIRECTORY(m)   (((m) & SHFL_TYPE_MASK) == SHFL_TYPE_DIRECTORY)
+/* Checks the mode flags indicate a symbolic link (S_ISLNK). */
+#define SHFL_IS_SYMLINK(m)     (((m) & SHFL_TYPE_MASK) == SHFL_TYPE_SYMLINK)
+
+/** The available additional information in a shfl_fsobjattr object. */
+enum shfl_fsobjattr_add {
+	/** No additional information is available / requested. */
+	SHFLFSOBJATTRADD_NOTHING = 1,
+	/**
+	 * The additional unix attributes (shfl_fsobjattr::u::unix_attr) are
+	 *  available / requested.
+	 */
+	SHFLFSOBJATTRADD_UNIX,
+	/**
+	 * The additional extended attribute size (shfl_fsobjattr::u::size) is
+	 *  available / requested.
+	 */
+	SHFLFSOBJATTRADD_EASIZE,
+	/**
+	 * The last valid item (inclusive).
+	 * The valid range is SHFLFSOBJATTRADD_NOTHING thru
+	 * SHFLFSOBJATTRADD_LAST.
+	 */
+	SHFLFSOBJATTRADD_LAST = SHFLFSOBJATTRADD_EASIZE,
+
+	/** The usual 32-bit hack. */
+	SHFLFSOBJATTRADD_32BIT_SIZE_HACK = 0x7fffffff
+};
+
+/**
+ * Additional unix Attributes, these are available when
+ * shfl_fsobjattr.additional == SHFLFSOBJATTRADD_UNIX.
+ */
+struct shfl_fsobjattr_unix {
+	/**
+	 * The user owning the filesystem object (st_uid).
+	 * This field is ~0U if not supported.
+	 */
+	u32 uid;
+
+	/**
+	 * The group the filesystem object is assigned (st_gid).
+	 * This field is ~0U if not supported.
+	 */
+	u32 gid;
+
+	/**
+	 * Number of hard links to this filesystem object (st_nlink).
+	 * This field is 1 if the filesystem doesn't support hardlinking or
+	 * the information isn't available.
+	 */
+	u32 hardlinks;
+
+	/**
+	 * The device number of the device which this filesystem object resides
+	 * on (st_dev). This field is 0 if this information is not available.
+	 */
+	u32 inode_id_device;
+
+	/**
+	 * The unique identifier (within the filesystem) of this filesystem
+	 * object (st_ino). Together with inode_id_device, this field can be
+	 * used as a OS wide unique id, when both their values are not 0.
+	 * This field is 0 if the information is not available.
+	 */
+	u64 inode_id;
+
+	/**
+	 * User flags (st_flags).
+	 * This field is 0 if this information is not available.
+	 */
+	u32 flags;
+
+	/**
+	 * The current generation number (st_gen).
+	 * This field is 0 if this information is not available.
+	 */
+	u32 generation_id;
+
+	/**
+	 * The device number of a char. or block device type object (st_rdev).
+	 * This field is 0 if the file isn't a char. or block device or when
+	 * the OS doesn't use the major+minor device idenfication scheme.
+	 */
+	u32 device;
+} __packed;
+
+/** Extended attribute size. */
+struct shfl_fsobjattr_easize {
+	/** Size of EAs. */
+	s64 cb;
+} __packed;
+
+/** Shared folder filesystem object attributes. */
+struct shfl_fsobjattr {
+	/** Mode flags (st_mode). SHFL_UNIX_*, SHFL_TYPE_*, and SHFL_DOS_*. */
+	u32 mode;
+
+	/** The additional attributes available. */
+	enum shfl_fsobjattr_add additional;
+
+	/**
+	 * Additional attributes.
+	 *
+	 * Unless explicitly specified to an API, the API can provide additional
+	 * data as it is provided by the underlying OS.
+	 */
+	union {
+		struct shfl_fsobjattr_unix unix_attr;
+		struct shfl_fsobjattr_easize size;
+	} __packed u;
+} __packed;
+VMMDEV_ASSERT_SIZE(shfl_fsobjattr, 44);
+
+struct shfl_timespec {
+	s64 ns_relative_to_unix_epoch;
+};
+
+/** Filesystem object information structure. */
+struct shfl_fsobjinfo {
+	/**
+	 * Logical size (st_size).
+	 * For normal files this is the size of the file.
+	 * For symbolic links, this is the length of the path name contained
+	 * in the symbolic link.
+	 * For other objects this fields needs to be specified.
+	 */
+	s64 size;
+
+	/** Disk allocation size (st_blocks * DEV_BSIZE). */
+	s64 allocated;
+
+	/** Time of last access (st_atime). */
+	struct shfl_timespec access_time;
+
+	/** Time of last data modification (st_mtime). */
+	struct shfl_timespec modification_time;
+
+	/**
+	 * Time of last status change (st_ctime).
+	 * If not available this is set to modification_time.
+	 */
+	struct shfl_timespec change_time;
+
+	/**
+	 * Time of file birth (st_birthtime).
+	 * If not available this is set to change_time.
+	 */
+	struct shfl_timespec birth_time;
+
+	/** Attributes. */
+	struct shfl_fsobjattr attr;
+
+} __packed;
+VMMDEV_ASSERT_SIZE(shfl_fsobjinfo, 92);
+
+/**
+ * result of an open/create request.
+ * Along with handle value the result code
+ * identifies what has happened while
+ * trying to open the object.
+ */
+enum shfl_create_result {
+	SHFL_NO_RESULT,
+	/** Specified path does not exist. */
+	SHFL_PATH_NOT_FOUND,
+	/** Path to file exists, but the last component does not. */
+	SHFL_FILE_NOT_FOUND,
+	/** File already exists and either has been opened or not. */
+	SHFL_FILE_EXISTS,
+	/** New file was created. */
+	SHFL_FILE_CREATED,
+	/** Existing file was replaced or overwritten. */
+	SHFL_FILE_REPLACED
+};
+
+/* No flags. Initialization value. */
+#define SHFL_CF_NONE                  (0x00000000)
+
+/*
+ * Only lookup the object, do not return a handle. When this is set all other
+ * flags are ignored.
+ */
+#define SHFL_CF_LOOKUP                (0x00000001)
+
+/*
+ * Open parent directory of specified object.
+ * Useful for the corresponding Windows FSD flag
+ * and for opening paths like \\dir\\*.* to search the 'dir'.
+ */
+#define SHFL_CF_OPEN_TARGET_DIRECTORY (0x00000002)
+
+/* Create/open a directory. */
+#define SHFL_CF_DIRECTORY             (0x00000004)
+
+/*
+ *  Open/create action to do if object exists
+ *  and if the object does not exists.
+ *  REPLACE file means atomically DELETE and CREATE.
+ *  OVERWRITE file means truncating the file to 0 and
+ *  setting new size.
+ *  When opening an existing directory REPLACE and OVERWRITE
+ *  actions are considered invalid, and cause returning
+ *  FILE_EXISTS with NIL handle.
+ */
+#define SHFL_CF_ACT_MASK_IF_EXISTS      (0x000000f0)
+#define SHFL_CF_ACT_MASK_IF_NEW         (0x00000f00)
+
+/* What to do if object exists. */
+#define SHFL_CF_ACT_OPEN_IF_EXISTS      (0x00000000)
+#define SHFL_CF_ACT_FAIL_IF_EXISTS      (0x00000010)
+#define SHFL_CF_ACT_REPLACE_IF_EXISTS   (0x00000020)
+#define SHFL_CF_ACT_OVERWRITE_IF_EXISTS (0x00000030)
+
+/* What to do if object does not exist. */
+#define SHFL_CF_ACT_CREATE_IF_NEW       (0x00000000)
+#define SHFL_CF_ACT_FAIL_IF_NEW         (0x00000100)
+
+/* Read/write requested access for the object. */
+#define SHFL_CF_ACCESS_MASK_RW          (0x00003000)
+
+/* No access requested. */
+#define SHFL_CF_ACCESS_NONE             (0x00000000)
+/* Read access requested. */
+#define SHFL_CF_ACCESS_READ             (0x00001000)
+/* Write access requested. */
+#define SHFL_CF_ACCESS_WRITE            (0x00002000)
+/* Read/Write access requested. */
+#define SHFL_CF_ACCESS_READWRITE	(0x00003000)
+
+/* Requested share access for the object. */
+#define SHFL_CF_ACCESS_MASK_DENY        (0x0000c000)
+
+/* Allow any access. */
+#define SHFL_CF_ACCESS_DENYNONE         (0x00000000)
+/* Do not allow read. */
+#define SHFL_CF_ACCESS_DENYREAD         (0x00004000)
+/* Do not allow write. */
+#define SHFL_CF_ACCESS_DENYWRITE        (0x00008000)
+/* Do not allow access. */
+#define SHFL_CF_ACCESS_DENYALL          (0x0000c000)
+
+/* Requested access to attributes of the object. */
+#define SHFL_CF_ACCESS_MASK_ATTR        (0x00030000)
+
+/* No access requested. */
+#define SHFL_CF_ACCESS_ATTR_NONE        (0x00000000)
+/* Read access requested. */
+#define SHFL_CF_ACCESS_ATTR_READ        (0x00010000)
+/* Write access requested. */
+#define SHFL_CF_ACCESS_ATTR_WRITE       (0x00020000)
+/* Read/Write access requested. */
+#define SHFL_CF_ACCESS_ATTR_READWRITE   (0x00030000)
+
+/*
+ * The file is opened in append mode.
+ * Ignored if SHFL_CF_ACCESS_WRITE is not set.
+ */
+#define SHFL_CF_ACCESS_APPEND           (0x00040000)
+
+/** Create parameters buffer struct for SHFL_FN_CREATE call */
+struct shfl_createparms {
+	/** Returned handle of opened object. */
+	u64 handle;
+
+	/** Returned result of the operation */
+	enum shfl_create_result result;
+
+	/** SHFL_CF_* */
+	u32 create_flags;
+
+	/**
+	 * Attributes of object to create and
+	 * returned actual attributes of opened/created object.
+	 */
+	struct shfl_fsobjinfo info;
+} __packed;
+
+/** Shared Folder directory information */
+struct shfl_dirinfo {
+	/** Full information about the object. */
+	struct shfl_fsobjinfo info;
+	/**
+	 * The length of the short field (number of UTF16 chars).
+	 * It is 16-bit for reasons of alignment.
+	 */
+	u16 short_name_len;
+	/**
+	 * The short name for 8.3 compatibility.
+	 * Empty string if not available.
+	 */
+	u16 short_name[14];
+	struct shfl_string name;
+};
+
+/** Shared folder filesystem properties. */
+struct shfl_fsproperties {
+	/**
+	 * The maximum size of a filesystem object name.
+	 * This does not include the '\\0'.
+	 */
+	u32 max_component_len;
+
+	/**
+	 * True if the filesystem is remote.
+	 * False if the filesystem is local.
+	 */
+	bool remote;
+
+	/**
+	 * True if the filesystem is case sensitive.
+	 * False if the filesystem is case insensitive.
+	 */
+	bool case_sensitive;
+
+	/**
+	 * True if the filesystem is mounted read only.
+	 * False if the filesystem is mounted read write.
+	 */
+	bool read_only;
+
+	/**
+	 * True if the filesystem can encode unicode object names.
+	 * False if it can't.
+	 */
+	bool supports_unicode;
+
+	/**
+	 * True if the filesystem is compresses.
+	 * False if it isn't or we don't know.
+	 */
+	bool compressed;
+
+	/**
+	 * True if the filesystem compresses of individual files.
+	 * False if it doesn't or we don't know.
+	 */
+	bool file_compression;
+};
+VMMDEV_ASSERT_SIZE(shfl_fsproperties, 12);
+
+struct shfl_volinfo {
+	s64 total_allocation_bytes;
+	s64 available_allocation_bytes;
+	u32 bytes_per_allocation_unit;
+	u32 bytes_per_sector;
+	u32 serial;
+	struct shfl_fsproperties properties;
+};
+
+
+/** SHFL_FN_MAP_FOLDER Parameters structure. */
+struct shfl_map_folder {
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string buffer.
+	 */
+	struct vmmdev_hgcm_function_parameter path;
+
+	/**
+	 * pointer, out: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * pointer, in: UTF16
+	 * Path delimiter
+	 */
+	struct vmmdev_hgcm_function_parameter delimiter;
+
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Case senstive flag
+	 */
+	struct vmmdev_hgcm_function_parameter case_sensitive;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_MAP_FOLDER (4)
+
+
+/** SHFL_FN_UNMAP_FOLDER Parameters structure. */
+struct shfl_unmap_folder {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_UNMAP_FOLDER (1)
+
+
+/** SHFL_FN_CREATE Parameters structure. */
+struct shfl_create {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string buffer.
+	 */
+	struct vmmdev_hgcm_function_parameter path;
+
+	/**
+	 * pointer, in/out:
+	 * Points to struct shfl_createparms buffer.
+	 */
+	struct vmmdev_hgcm_function_parameter parms;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_CREATE (3)
+
+
+/** SHFL_FN_CLOSE Parameters structure. */
+struct shfl_close {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * value64, in:
+	 * SHFLHANDLE (u64) of object to close.
+	 */
+	struct vmmdev_hgcm_function_parameter handle;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_CLOSE (2)
+
+
+/** SHFL_FN_READ Parameters structure. */
+struct shfl_read {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * value64, in:
+	 * SHFLHANDLE (u64) of object to read from.
+	 */
+	struct vmmdev_hgcm_function_parameter handle;
+
+	/**
+	 * value64, in:
+	 * Offset to read from.
+	 */
+	struct vmmdev_hgcm_function_parameter offset;
+
+	/**
+	 * value64, in/out:
+	 * Bytes to read/How many were read.
+	 */
+	struct vmmdev_hgcm_function_parameter cb;
+
+	/**
+	 * pointer, out:
+	 * Buffer to place data to.
+	 */
+	struct vmmdev_hgcm_function_parameter buffer;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_READ (5)
+
+
+/** SHFL_FN_WRITE Parameters structure. */
+struct shfl_write {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * value64, in:
+	 * SHFLHANDLE (u64) of object to write to.
+	 */
+	struct vmmdev_hgcm_function_parameter handle;
+
+	/**
+	 * value64, in:
+	 * Offset to write to.
+	 */
+	struct vmmdev_hgcm_function_parameter offset;
+
+	/**
+	 * value64, in/out:
+	 * Bytes to write/How many were written.
+	 */
+	struct vmmdev_hgcm_function_parameter cb;
+
+	/**
+	 * pointer, in:
+	 * Data to write.
+	 */
+	struct vmmdev_hgcm_function_parameter buffer;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_WRITE (5)
+
+
+/*
+ * SHFL_FN_LIST
+ * Listing information includes variable length RTDIRENTRY[EX] structures.
+ */
+
+#define SHFL_LIST_NONE			0
+#define SHFL_LIST_RETURN_ONE		1
+
+/** SHFL_FN_LIST Parameters structure. */
+struct shfl_list {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * value64, in:
+	 * SHFLHANDLE (u64) of object to be listed.
+	 */
+	struct vmmdev_hgcm_function_parameter handle;
+
+	/**
+	 * value32, in:
+	 * List flags SHFL_LIST_*.
+	 */
+	struct vmmdev_hgcm_function_parameter flags;
+
+	/**
+	 * value32, in/out:
+	 * Bytes to be used for listing information/How many bytes were used.
+	 */
+	struct vmmdev_hgcm_function_parameter cb;
+
+	/**
+	 * pointer, in/optional
+	 * Points to struct shfl_string buffer that specifies a search path.
+	 */
+	struct vmmdev_hgcm_function_parameter path;
+
+	/**
+	 * pointer, out:
+	 * Buffer to place listing information to. (struct shfl_dirinfo)
+	 */
+	struct vmmdev_hgcm_function_parameter buffer;
+
+	/**
+	 * value32, in/out:
+	 * Indicates a key where the listing must be resumed.
+	 * in: 0 means start from begin of object.
+	 * out: 0 means listing completed.
+	 */
+	struct vmmdev_hgcm_function_parameter resume_point;
+
+	/**
+	 * pointer, out:
+	 * Number of files returned
+	 */
+	struct vmmdev_hgcm_function_parameter file_count;
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_LIST (8)
+
+
+/** SHFL_FN_READLINK Parameters structure. */
+struct shfl_readLink {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string buffer.
+	 */
+	struct vmmdev_hgcm_function_parameter path;
+
+	/**
+	 * pointer, out:
+	 * Buffer to place data to.
+	 */
+	struct vmmdev_hgcm_function_parameter buffer;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_READLINK (3)
+
+
+/* SHFL_FN_INFORMATION */
+
+/* Mask of Set/Get bit. */
+#define SHFL_INFO_MODE_MASK    (0x1)
+/* Get information */
+#define SHFL_INFO_GET          (0x0)
+/* Set information */
+#define SHFL_INFO_SET          (0x1)
+
+/* Get name of the object. */
+#define SHFL_INFO_NAME         (0x2)
+/* Set size of object (extend/trucate); only applies to file objects */
+#define SHFL_INFO_SIZE         (0x4)
+/* Get/Set file object info. */
+#define SHFL_INFO_FILE         (0x8)
+/* Get volume information. */
+#define SHFL_INFO_VOLUME       (0x10)
+
+/** SHFL_FN_INFORMATION Parameters structure. */
+struct shfl_information {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * value64, in:
+	 * SHFLHANDLE (u64) of object to be listed.
+	 */
+	struct vmmdev_hgcm_function_parameter handle;
+
+	/**
+	 * value32, in:
+	 * SHFL_INFO_*
+	 */
+	struct vmmdev_hgcm_function_parameter flags;
+
+	/**
+	 * value32, in/out:
+	 * Bytes to be used for information/How many bytes were used.
+	 */
+	struct vmmdev_hgcm_function_parameter cb;
+
+	/**
+	 * pointer, in/out:
+	 * Information to be set/get (shfl_fsobjinfo or shfl_string). Do not
+	 * forget to set the shfl_fsobjinfo::attr::additional for a get
+	 * operation as well.
+	 */
+	struct vmmdev_hgcm_function_parameter info;
+
+};
+
+/* Number of parameters */
+#define SHFL_CPARMS_INFORMATION (5)
+
+
+/* SHFL_FN_REMOVE */
+
+#define SHFL_REMOVE_FILE        (0x1)
+#define SHFL_REMOVE_DIR         (0x2)
+#define SHFL_REMOVE_SYMLINK     (0x4)
+
+/** SHFL_FN_REMOVE Parameters structure. */
+struct shfl_remove {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string buffer.
+	 */
+	struct vmmdev_hgcm_function_parameter path;
+
+	/**
+	 * value32, in:
+	 * remove flags (file/directory)
+	 */
+	struct vmmdev_hgcm_function_parameter flags;
+
+};
+
+#define SHFL_CPARMS_REMOVE  (3)
+
+
+/* SHFL_FN_RENAME */
+
+#define SHFL_RENAME_FILE                (0x1)
+#define SHFL_RENAME_DIR                 (0x2)
+#define SHFL_RENAME_REPLACE_IF_EXISTS   (0x4)
+
+/** SHFL_FN_RENAME Parameters structure. */
+struct shfl_rename {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string src.
+	 */
+	struct vmmdev_hgcm_function_parameter src;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string dest.
+	 */
+	struct vmmdev_hgcm_function_parameter dest;
+
+	/**
+	 * value32, in:
+	 * rename flags (file/directory)
+	 */
+	struct vmmdev_hgcm_function_parameter flags;
+
+};
+
+#define SHFL_CPARMS_RENAME  (4)
+
+
+/** SHFL_FN_SYMLINK Parameters structure. */
+struct shfl_symlink {
+	/**
+	 * pointer, in: SHFLROOT (u32)
+	 * Root handle of the mapping which name is queried.
+	 */
+	struct vmmdev_hgcm_function_parameter root;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string of path for the new symlink.
+	 */
+	struct vmmdev_hgcm_function_parameter new_path;
+
+	/**
+	 * pointer, in:
+	 * Points to struct shfl_string of destination for symlink.
+	 */
+	struct vmmdev_hgcm_function_parameter old_path;
+
+	/**
+	 * pointer, out:
+	 * Information about created symlink.
+	 */
+	struct vmmdev_hgcm_function_parameter info;
+
+};
+
+#define SHFL_CPARMS_SYMLINK  (4)
+
+#endif
diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
new file mode 100644
index 000000000000..0de37cb56f29
--- /dev/null
+++ b/fs/vboxsf/super.c
@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VirtualBox Guest Shared Folders support: Virtual File System.
+ *
+ * Module initialization/finalization
+ * File system registration/deregistration
+ * Superblock reading
+ * Few utility functions
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#include <linux/magic.h>
+#include <linux/module.h>
+#include <linux/nls.h>
+#include <linux/statfs.h>
+#include <linux/vbox_utils.h>
+#include <linux/vbsfmount.h>
+#include "vfsmod.h"
+
+MODULE_DESCRIPTION("Oracle VM VirtualBox Module for Host File System Access");
+MODULE_AUTHOR("Oracle Corporation");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_FS("vboxsf");
+
+static struct super_operations sf_super_ops; /* forward declaration */
+static struct kmem_cache *sf_inode_cachep;
+
+/* allocate global info, try to map host share */
+static int sf_glob_alloc(struct vbsf_mount_info_new *info,
+			 struct sf_glob_info **sf_gp)
+{
+	size_t name_len, str_len;
+	struct sf_glob_info *sf_g;
+	struct shfl_string *str_name = NULL;
+#ifdef CONFIG_NLS_DEFAULT
+	const char *nls_name = CONFIG_NLS_DEFAULT;
+#else
+	const char *nls_name = "";
+#endif
+	int err;
+
+	if (info->nullchar != '\0' ||
+	    info->signature[0] != VBSF_MOUNT_SIGNATURE_BYTE_0 ||
+	    info->signature[1] != VBSF_MOUNT_SIGNATURE_BYTE_1 ||
+	    info->signature[2] != VBSF_MOUNT_SIGNATURE_BYTE_2)
+		return -EINVAL;
+
+	sf_g = kzalloc(sizeof(*sf_g), GFP_KERNEL);
+	if (!sf_g)
+		return -ENOMEM;
+
+	info->name[sizeof(info->name) - 1] = 0;
+	info->nls_name[sizeof(info->nls_name) - 1] = 0;
+
+	name_len = strlen(info->name);
+	str_len = offsetof(struct shfl_string, string.utf8) + name_len + 1;
+
+	str_name = kmalloc(str_len, GFP_KERNEL);
+	if (!str_name) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	str_name->length = name_len;
+	str_name->size = name_len + 1;
+	memcpy(str_name->string.utf8, info->name, name_len + 1);
+
+	if (info->nls_name[0])
+		nls_name = info->nls_name;
+
+	/* Load nls if not utf8 */
+	if (nls_name[0] && strcmp(nls_name, "utf8") != 0) {
+		sf_g->nls = load_nls(info->nls_name);
+		if (!sf_g->nls) {
+			err = -EINVAL;
+			goto fail;
+		}
+	} else {
+		sf_g->nls = NULL;
+	}
+
+	err = vboxsf_map_folder(str_name, &sf_g->root);
+	if (err)
+		goto fail;
+
+	kfree(str_name);
+
+	sf_g->ttl = info->ttl;
+	sf_g->uid = info->uid;
+	sf_g->gid = info->gid;
+
+	if ((size_t)info->length >= sizeof(struct vbsf_mount_info_new)) {
+		/* new fields */
+		sf_g->dmode = info->dmode;
+		sf_g->fmode = info->fmode;
+		sf_g->dmask = info->dmask;
+		sf_g->fmask = info->fmask;
+	} else {
+		sf_g->dmode = ~0;
+		sf_g->fmode = ~0;
+	}
+
+	*sf_gp = sf_g;
+	return 0;
+
+fail:
+	if (sf_g->nls)
+		unload_nls(sf_g->nls);
+
+	kfree(str_name);
+	kfree(sf_g);
+
+	return err;
+}
+
+/* unmap the share and free global info [sf_g] */
+static void sf_glob_free(struct sf_glob_info *sf_g)
+{
+	vboxsf_unmap_folder(sf_g->root);
+
+	if (sf_g->nls)
+		unload_nls(sf_g->nls);
+
+	kfree(sf_g);
+}
+
+/*
+ * This is called when vfs mounts the fs and wants to read the super_block.
+ *
+ * calls [sf_glob_alloc] to map the folder and allocate global
+ * information structure.
+ *
+ * initializes [sb], initializes root inode and dentry.
+ *
+ * should respect [flags]
+ */
+static int sf_read_super(struct super_block *sb, void *data, int flags)
+{
+	struct vbsf_mount_info_new *info = data;
+	struct shfl_string *path = NULL;
+	struct shfl_fsobjinfo fsinfo;
+	struct sf_glob_info *sf_g;
+	struct dentry *droot;
+	struct inode *iroot;
+	int err;
+
+	if (!info)
+		return -EINVAL;
+
+	if (flags & MS_REMOUNT)
+		return -EINVAL;
+
+	err = sf_glob_alloc(info, &sf_g);
+	if (err)
+		return err;
+
+	path = kmalloc(SHFLSTRING_HEADER_SIZE + 2, GFP_KERNEL);
+	if (!path) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	path->length = 1;
+	path->size = 2;
+	path->string.utf8[0] = '/';
+	path->string.utf8[1] = 0;
+
+	err = sf_stat(__func__, sf_g, path, &fsinfo, 0);
+	if (err)
+		goto fail;
+
+	sb->s_magic = 0xface;
+	sb->s_blocksize = 1024;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_op = &sf_super_ops;
+
+	iroot = iget_locked(sb, 0);
+	if (!iroot) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	GET_INODE_INFO(iroot)->path = path;
+	sf_init_inode(sf_g, iroot, &fsinfo);
+	unlock_new_inode(iroot);
+
+	droot = d_make_root(iroot);
+	if (!droot) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	sb->s_root = droot;
+	SET_GLOB_INFO(sb, sf_g);
+	return 0;
+
+fail:
+	kfree(path);
+	sf_glob_free(sf_g);
+	return err;
+}
+
+static void sf_inode_init_once(void *data)
+{
+	struct sf_inode_info *sf_i = (struct sf_inode_info *)data;
+
+	inode_init_once(&sf_i->vfs_inode);
+}
+
+static struct inode *sf_alloc_inode(struct super_block *sb)
+{
+	struct sf_inode_info *sf_i;
+
+	sf_i = kmem_cache_alloc(sf_inode_cachep, GFP_NOFS);
+	if (!sf_i)
+		return NULL;
+
+	sf_i->path = NULL;
+	sf_i->force_restat = 0;
+	sf_i->force_reread = 0;
+	sf_i->file = NULL;
+	sf_i->handle = SHFL_HANDLE_NIL;
+
+	return &sf_i->vfs_inode;
+}
+
+static void sf_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(sf_inode_cachep, GET_INODE_INFO(inode));
+}
+
+static void sf_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, sf_i_callback);
+}
+
+/*
+ * This is called when vfs is about to destroy the [inode]. all
+ * resources associated with this [inode] must be cleared here.
+ */
+static void sf_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+	kfree(GET_INODE_INFO(inode)->path);
+}
+
+/*
+ * vfs is done with [sb] (umount called) call [sf_glob_free] to unmap
+ * the folder and free [sf_g]
+ */
+static void sf_put_super(struct super_block *sb)
+{
+	struct sf_glob_info *sf_g;
+
+	sf_g = GET_GLOB_INFO(sb);
+	sf_glob_free(sf_g);
+}
+
+static int sf_statfs(struct dentry *dentry, struct kstatfs *stat)
+{
+	struct super_block *sb = dentry->d_inode->i_sb;
+	struct sf_glob_info *sf_g;
+	struct shfl_volinfo SHFLVolumeInfo;
+	u32 buf_len;
+	int err;
+
+	sf_g = GET_GLOB_INFO(sb);
+	buf_len = sizeof(SHFLVolumeInfo);
+	err = vboxsf_fsinfo(sf_g->root, 0, SHFL_INFO_GET | SHFL_INFO_VOLUME,
+			    &buf_len, &SHFLVolumeInfo);
+	if (err)
+		return err;
+
+	stat->f_type = NFS_SUPER_MAGIC;	/* XXX vboxsf type? */
+	stat->f_bsize = SHFLVolumeInfo.bytes_per_allocation_unit;
+
+	do_div(SHFLVolumeInfo.total_allocation_bytes,
+	       SHFLVolumeInfo.bytes_per_allocation_unit);
+	stat->f_blocks = SHFLVolumeInfo.total_allocation_bytes;
+
+	do_div(SHFLVolumeInfo.available_allocation_bytes,
+	       SHFLVolumeInfo.bytes_per_allocation_unit);
+	stat->f_bfree  = SHFLVolumeInfo.available_allocation_bytes;
+	stat->f_bavail = SHFLVolumeInfo.available_allocation_bytes;
+
+	stat->f_files = 1000;
+	/*
+	 * Don't return 0 here since the guest may then think that it is not
+	 * possible to create any more files.
+	 */
+	stat->f_ffree = 1000;
+	stat->f_fsid.val[0] = 0;
+	stat->f_fsid.val[1] = 0;
+	stat->f_namelen = 255;
+	return 0;
+}
+
+static int sf_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+	struct sf_glob_info *sf_g;
+	struct sf_inode_info *sf_i;
+	struct inode *iroot;
+	struct shfl_fsobjinfo fsinfo;
+	int err;
+
+	sf_g = GET_GLOB_INFO(sb);
+	if (data && data[0] != 0) {
+		struct vbsf_mount_info_new *info =
+		    (struct vbsf_mount_info_new *)data;
+		if (info->signature[0] == VBSF_MOUNT_SIGNATURE_BYTE_0
+		    && info->signature[1] == VBSF_MOUNT_SIGNATURE_BYTE_1
+		    && info->signature[2] == VBSF_MOUNT_SIGNATURE_BYTE_2) {
+			sf_g->uid = info->uid;
+			sf_g->gid = info->gid;
+			sf_g->ttl = info->ttl;
+			sf_g->dmode = info->dmode;
+			sf_g->fmode = info->fmode;
+			sf_g->dmask = info->dmask;
+			sf_g->fmask = info->fmask;
+		}
+	}
+
+	iroot = ilookup(sb, 0);
+	if (!iroot)
+		return -ENOENT;
+
+	sf_i = GET_INODE_INFO(iroot);
+	err = sf_stat(__func__, sf_g, sf_i->path, &fsinfo, 0);
+	if (err == 0)
+		sf_init_inode(sf_g, iroot, &fsinfo);
+	else
+		vbg_warn("Error statting root fs after remount: %d\n", err);
+
+	return 0;
+}
+
+static struct super_operations sf_super_ops = {
+	.alloc_inode	= sf_alloc_inode,
+	.destroy_inode	= sf_destroy_inode,
+	.evict_inode	= sf_evict_inode,
+	.put_super	= sf_put_super,
+	.statfs		= sf_statfs,
+	.remount_fs	= sf_remount_fs
+};
+
+static struct dentry *sf_mount(struct file_system_type *fs_type, int flags,
+			       const char *dev_name, void *data)
+{
+	return mount_nodev(fs_type, flags, data, sf_read_super);
+}
+
+static struct file_system_type vboxsf_fs_type = {
+	.owner = THIS_MODULE,
+	.name = "vboxsf",
+	.mount = sf_mount,
+	.kill_sb = kill_anon_super
+};
+
+static int follow_symlinks;
+module_param(follow_symlinks, int, 0444);
+MODULE_PARM_DESC(follow_symlinks,
+		 "Let host resolve symlinks rather than showing them");
+
+/* Module initialization/finalization handlers */
+static int __init init(void)
+{
+	int err;
+
+	if (sizeof(struct vbsf_mount_info_new) > PAGE_SIZE) {
+		vbg_err("vboxsf: Mount information structure is too large %zd; Must be less than or equal to %ld\n",
+			sizeof(struct vbsf_mount_info_new), PAGE_SIZE);
+		return -EINVAL;
+	}
+
+	sf_inode_cachep = kmem_cache_create("vboxsf_inode_cache",
+					     sizeof(struct sf_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+					     sf_inode_init_once);
+	if (sf_inode_cachep == NULL)
+		return -ENOMEM;
+
+	err = register_filesystem(&vboxsf_fs_type);
+	if (err)
+		return err;
+
+	err = vboxsf_connect();
+	if (err) {
+		vbg_err("vboxsf_connect error %d\n", err);
+		goto fail_unregisterfs;
+	}
+
+	err = vboxsf_set_utf8();
+	if (err) {
+		vbg_err("vboxsf_setutf8 error %d\n", err);
+		goto fail_disconnect;
+	}
+
+	if (!follow_symlinks) {
+		err = vboxsf_set_symlinks();
+		if (err)
+			vbg_warn("vboxsf: Unable to show symlinks: %d\n", err);
+	}
+
+	return 0;
+
+fail_disconnect:
+	vboxsf_disconnect();
+fail_unregisterfs:
+	unregister_filesystem(&vboxsf_fs_type);
+	return err;
+}
+
+static void __exit fini(void)
+{
+	vboxsf_disconnect();
+	unregister_filesystem(&vboxsf_fs_type);
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(sf_inode_cachep);
+}
+
+module_init(init);
+module_exit(fini);
diff --git a/fs/vboxsf/utils.c b/fs/vboxsf/utils.c
new file mode 100644
index 000000000000..9d457d0ac001
--- /dev/null
+++ b/fs/vboxsf/utils.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VirtualBox Guest Shared Folders support: Utility functions.
+ * Mainly conversion from/to VirtualBox/Linux data structures.
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#include <linux/namei.h>
+#include <linux/nls.h>
+#include <linux/sizes.h>
+#include <linux/vfs.h>
+#include "vfsmod.h"
+
+/*
+ * sf_reg_aops and sf_backing_dev_info are just quick implementations to make
+ * sendfile work. For more information have a look at
+ *
+ *   http://us1.samba.org/samba/ftp/cifs-cvs/ols2006-fs-tutorial-smf.odp
+ *
+ * and the sample implementation
+ *
+ *   http://pserver.samba.org/samba/ftp/cifs-cvs/samplefs.tar.gz
+ */
+
+static void sf_timespec_from_vbox(struct timespec *tv,
+				  const struct shfl_timespec *ts)
+{
+	s64 nsec, t = ts->ns_relative_to_unix_epoch;
+
+	nsec = do_div(t, 1000000000);
+	tv->tv_sec = t;
+	tv->tv_nsec = nsec;
+}
+
+static void sf_timespec_to_vbox(struct shfl_timespec *ts,
+				const struct timespec *tv)
+{
+	s64 t = (s64) tv->tv_nsec + (s64) tv->tv_sec * 1000000000;
+
+	ts->ns_relative_to_unix_epoch = t;
+}
+
+/* set [inode] attributes based on [info], uid/gid based on [sf_g] */
+void sf_init_inode(struct sf_glob_info *sf_g, struct inode *inode,
+		   const struct shfl_fsobjinfo *info)
+{
+	const struct shfl_fsobjattr *attr;
+	s64 allocated;
+	int mode;
+
+	attr = &info->attr;
+
+#define mode_set(r) ((attr->mode & (SHFL_UNIX_##r)) ? (S_##r) : 0)
+
+	mode = mode_set(ISUID);
+	mode |= mode_set(ISGID);
+
+	mode |= mode_set(IRUSR);
+	mode |= mode_set(IWUSR);
+	mode |= mode_set(IXUSR);
+
+	mode |= mode_set(IRGRP);
+	mode |= mode_set(IWGRP);
+	mode |= mode_set(IXGRP);
+
+	mode |= mode_set(IROTH);
+	mode |= mode_set(IWOTH);
+	mode |= mode_set(IXOTH);
+
+#undef mode_set
+
+	inode->i_mapping->a_ops = &sf_reg_aops;
+
+	if (SHFL_IS_DIRECTORY(attr->mode)) {
+		inode->i_mode = sf_g->dmode != ~0 ? (sf_g->dmode & 0777) : mode;
+		inode->i_mode &= ~sf_g->dmask;
+		inode->i_mode |= S_IFDIR;
+		inode->i_op = &sf_dir_iops;
+		inode->i_fop = &sf_dir_fops;
+		/*
+		 * XXX: this probably should be set to the number of entries
+		 * in the directory plus two (. ..)
+		 */
+		set_nlink(inode, 1);
+	} else if (SHFL_IS_SYMLINK(attr->mode)) {
+		inode->i_mode = sf_g->fmode != ~0 ? (sf_g->fmode & 0777) : mode;
+		inode->i_mode &= ~sf_g->fmask;
+		inode->i_mode |= S_IFLNK;
+		inode->i_op = &sf_lnk_iops;
+		set_nlink(inode, 1);
+	} else {
+		inode->i_mode = sf_g->fmode != ~0 ? (sf_g->fmode & 0777) : mode;
+		inode->i_mode &= ~sf_g->fmask;
+		inode->i_mode |= S_IFREG;
+		inode->i_op = &sf_reg_iops;
+		inode->i_fop = &sf_reg_fops;
+		set_nlink(inode, 1);
+	}
+
+	inode->i_uid = make_kuid(current_user_ns(), sf_g->uid);
+	inode->i_gid = make_kgid(current_user_ns(), sf_g->gid);
+
+	inode->i_size = info->size;
+	inode->i_blkbits = 12;
+	/* i_blocks always in units of 512 bytes! */
+	allocated = info->allocated + 511;
+	do_div(allocated, 512);
+	inode->i_blocks = allocated;
+
+	sf_timespec_from_vbox(&inode->i_atime, &info->access_time);
+	sf_timespec_from_vbox(&inode->i_ctime, &info->change_time);
+	sf_timespec_from_vbox(&inode->i_mtime, &info->modification_time);
+}
+
+int sf_stat(const char *caller, struct sf_glob_info *sf_g,
+	    struct shfl_string *path, struct shfl_fsobjinfo *result,
+	    int ok_to_fail)
+{
+	struct shfl_createparms params = {};
+	int err;
+
+	params.handle = SHFL_HANDLE_NIL;
+	params.create_flags = SHFL_CF_LOOKUP | SHFL_CF_ACT_FAIL_IF_NEW;
+
+	err = vboxsf_create(sf_g->root, path, &params);
+	if (err)
+		return err;
+
+	if (params.result != SHFL_FILE_EXISTS)
+		return -ENOENT;
+
+	*result = params.info;
+	return 0;
+}
+
+/*
+ * This is called indirectly as iop through [sf_getattr]. The job is to find
+ * out whether dentry/inode is still valid. the test is failed if [dentry]
+ * does not have an inode or [sf_stat] is unsuccessful, otherwise we return
+ * success and update inode attributes.
+ */
+int sf_inode_revalidate(struct dentry *dentry)
+{
+	int err;
+	struct sf_glob_info *sf_g;
+	struct sf_inode_info *sf_i;
+	struct shfl_fsobjinfo info;
+
+	if (!dentry || !dentry->d_inode)
+		return -EINVAL;
+
+	sf_g = GET_GLOB_INFO(dentry->d_inode->i_sb);
+	sf_i = GET_INODE_INFO(dentry->d_inode);
+
+	if (!sf_i->force_restat) {
+		if (time_before(jiffies, dentry->d_time + sf_g->ttl))
+			return 0;
+	}
+
+	err = sf_stat(__func__, sf_g, sf_i->path, &info, 1);
+	if (err)
+		return err;
+
+	dentry->d_time = jiffies;
+	sf_i->force_restat = 0;
+	sf_init_inode(sf_g, dentry->d_inode, &info);
+	return 0;
+}
+
+int sf_getattr(const struct path *path, struct kstat *kstat, u32 request_mask,
+	       unsigned int flags)
+{
+	int err;
+	struct dentry *dentry = path->dentry;
+
+	err = sf_inode_revalidate(dentry);
+	if (err)
+		return err;
+
+	generic_fillattr(dentry->d_inode, kstat);
+	return 0;
+}
+
+int sf_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct sf_glob_info *sf_g;
+	struct sf_inode_info *sf_i;
+	struct shfl_createparms params = {};
+	struct shfl_fsobjinfo info = {};
+	uint32_t buf_len;
+	int err;
+
+	sf_g = GET_GLOB_INFO(dentry->d_inode->i_sb);
+	sf_i = GET_INODE_INFO(dentry->d_inode);
+
+	params.handle = SHFL_HANDLE_NIL;
+	params.create_flags = SHFL_CF_ACT_OPEN_IF_EXISTS
+	    | SHFL_CF_ACT_FAIL_IF_NEW | SHFL_CF_ACCESS_ATTR_WRITE;
+
+	/* this is at least required for Posix hosts */
+	if (iattr->ia_valid & ATTR_SIZE)
+		params.create_flags |= SHFL_CF_ACCESS_WRITE;
+
+	err = vboxsf_create(sf_g->root, sf_i->path, &params);
+	if (err)
+		return err;
+
+	if (params.result != SHFL_FILE_EXISTS)
+		return -ENOENT;
+
+#define mode_set(r) ((iattr->ia_mode & (S_##r)) ? SHFL_UNIX_##r : 0)
+
+	/*
+	 * Setting the file size and setting the other attributes has to
+	 * be handled separately.
+	 */
+	if (iattr->ia_valid & (ATTR_MODE | ATTR_ATIME | ATTR_MTIME)) {
+		if (iattr->ia_valid & ATTR_MODE) {
+			info.attr.mode = mode_set(ISUID);
+			info.attr.mode |= mode_set(ISGID);
+			info.attr.mode |= mode_set(IRUSR);
+			info.attr.mode |= mode_set(IWUSR);
+			info.attr.mode |= mode_set(IXUSR);
+			info.attr.mode |= mode_set(IRGRP);
+			info.attr.mode |= mode_set(IWGRP);
+			info.attr.mode |= mode_set(IXGRP);
+			info.attr.mode |= mode_set(IROTH);
+			info.attr.mode |= mode_set(IWOTH);
+			info.attr.mode |= mode_set(IXOTH);
+
+			if (iattr->ia_mode & S_IFDIR)
+				info.attr.mode |= SHFL_TYPE_DIRECTORY;
+			else
+				info.attr.mode |= SHFL_TYPE_FILE;
+		}
+
+		if (iattr->ia_valid & ATTR_ATIME)
+			sf_timespec_to_vbox(&info.access_time,
+					    &iattr->ia_atime);
+
+		if (iattr->ia_valid & ATTR_MTIME)
+			sf_timespec_to_vbox(&info.modification_time,
+					    &iattr->ia_mtime);
+
+		/*
+		 * Ignore ctime (inode change time) as it can't be set
+		 * from userland anyway.
+		 */
+
+		buf_len = sizeof(info);
+		err = vboxsf_fsinfo(sf_g->root, params.handle,
+				   SHFL_INFO_SET | SHFL_INFO_FILE, &buf_len,
+				   &info);
+		if (err)
+			goto out;
+	}
+
+#undef mode_set
+
+	if (iattr->ia_valid & ATTR_SIZE) {
+		memset(&info, 0, sizeof(info));
+		info.size = iattr->ia_size;
+		buf_len = sizeof(info);
+		err = vboxsf_fsinfo(sf_g->root, params.handle,
+				   SHFL_INFO_SET | SHFL_INFO_SIZE, &buf_len,
+				   &info);
+		if (err)
+			goto out;
+	}
+
+	err = sf_inode_revalidate(dentry);
+out:
+	vboxsf_close(sf_g->root, params.handle);
+	return err;
+}
+
+static int sf_make_path(const char *caller, struct sf_inode_info *sf_i,
+			const char *d_name, size_t d_len,
+			struct shfl_string **result)
+{
+	size_t path_len, shflstring_len;
+	struct shfl_string *tmp;
+	uint16_t p_len;
+	uint8_t *p_name;
+	int fRoot = 0;
+
+	p_len = sf_i->path->length;
+	p_name = sf_i->path->string.utf8;
+
+	if (p_len == 1 && *p_name == '/') {
+		path_len = d_len + 1;
+		fRoot = 1;
+	} else {
+		/* lengths of constituents plus terminating zero plus slash  */
+		path_len = p_len + d_len + 2;
+		if (path_len > 0xffff)
+			return -ENAMETOOLONG;
+	}
+
+	shflstring_len = offsetof(struct shfl_string, string.utf8) + path_len;
+	tmp = kmalloc(shflstring_len, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	tmp->length = path_len - 1;
+	tmp->size = path_len;
+
+	if (fRoot)
+		memcpy(&tmp->string.utf8[0], d_name, d_len + 1);
+	else {
+		memcpy(&tmp->string.utf8[0], p_name, p_len);
+		tmp->string.utf8[p_len] = '/';
+		memcpy(&tmp->string.utf8[p_len + 1], d_name, d_len);
+		tmp->string.utf8[p_len + 1 + d_len] = '\0';
+	}
+
+	*result = tmp;
+	return 0;
+}
+
+/*
+ * [dentry] contains string encoded in coding system that corresponds
+ * to [sf_g]->nls, we must convert it to UTF8 here and pass down to
+ * [sf_make_path] which will allocate struct shfl_string and fill it in
+ */
+int sf_path_from_dentry(const char *caller, struct sf_glob_info *sf_g,
+			struct sf_inode_info *sf_i, struct dentry *dentry,
+			struct shfl_string **result)
+{
+	int err;
+	const char *d_name;
+	size_t d_len;
+	const char *name;
+	size_t len = 0;
+
+	d_name = dentry->d_name.name;
+	d_len = dentry->d_name.len;
+
+	if (sf_g->nls) {
+		size_t in_len, i, out_bound_len;
+		const char *in;
+		char *out;
+
+		in = d_name;
+		in_len = d_len;
+
+		out_bound_len = PATH_MAX;
+		out = kmalloc(out_bound_len, GFP_KERNEL);
+		name = out;
+
+		for (i = 0; i < d_len; ++i) {
+			wchar_t uni;
+			int nb;
+
+			nb = sf_g->nls->char2uni(in, in_len, &uni);
+			if (nb < 0) {
+				err = -EINVAL;
+				goto fail;
+			}
+			in_len -= nb;
+			in += nb;
+
+			nb = utf32_to_utf8(uni, out, out_bound_len);
+			if (nb < 0) {
+				err = -EINVAL;
+				goto fail;
+			}
+			out_bound_len -= nb;
+			out += nb;
+			len += nb;
+		}
+		if (len >= PATH_MAX - 1) {
+			err = -ENAMETOOLONG;
+			goto fail;
+		}
+
+		*out = 0;
+	} else {
+		name = d_name;
+		len = d_len;
+	}
+
+	err = sf_make_path(caller, sf_i, name, len, result);
+	if (name != d_name)
+		kfree(name);
+
+	return err;
+
+fail:
+	kfree(name);
+	return err;
+}
+
+int sf_nlscpy(struct sf_glob_info *sf_g,
+	      char *name, size_t name_bound_len,
+	      const unsigned char *utf8_name, size_t utf8_len)
+{
+	if (sf_g->nls) {
+		const char *in;
+		char *out;
+		size_t out_len;
+		size_t out_bound_len;
+		size_t in_bound_len;
+
+		in = utf8_name;
+		in_bound_len = utf8_len;
+
+		out = name;
+		out_len = 0;
+		out_bound_len = name_bound_len;
+
+		while (in_bound_len) {
+			int nb;
+			unicode_t uni;
+
+			nb = utf8_to_utf32(in, in_bound_len, &uni);
+			if (nb < 0)
+				return -EINVAL;
+
+			in += nb;
+			in_bound_len -= nb;
+
+			nb = sf_g->nls->uni2char(uni, out, out_bound_len);
+			if (nb < 0)
+				return nb;
+
+			out += nb;
+			out_bound_len -= nb;
+			out_len += nb;
+		}
+
+		*out = 0;
+	} else {
+		if (utf8_len + 1 > name_bound_len)
+			return -ENAMETOOLONG;
+
+		memcpy(name, utf8_name, utf8_len + 1);
+	}
+	return 0;
+}
+
+static struct sf_dir_buf *sf_dir_buf_alloc(void)
+{
+	struct sf_dir_buf *b;
+
+	b = kmalloc(sizeof(*b), GFP_KERNEL);
+	if (!b)
+		return NULL;
+
+	b->buf = kmalloc(DIR_BUFFER_SIZE, GFP_KERNEL);
+	if (!b->buf) {
+		kfree(b);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&b->head);
+	b->entries = 0;
+	b->used = 0;
+	b->free = DIR_BUFFER_SIZE;
+
+	return b;
+}
+
+static void sf_dir_buf_free(struct sf_dir_buf *b)
+{
+	list_del(&b->head);
+	kfree(b->buf);
+	kfree(b);
+}
+
+/**
+ * Free the directory buffer.
+ * @p		sf_dir_info buffer to free
+ */
+void sf_dir_info_free(struct sf_dir_info *p)
+{
+	struct list_head *list, *pos, *tmp;
+
+	list = &p->info_list;
+	list_for_each_safe(pos, tmp, list) {
+		struct sf_dir_buf *b;
+
+		b = list_entry(pos, struct sf_dir_buf, head);
+		sf_dir_buf_free(b);
+	}
+	kfree(p);
+}
+
+/**
+ * Empty (but not free) the directory buffer.
+ * @p		sf_dir_info buffer to empty
+ */
+void sf_dir_info_empty(struct sf_dir_info *p)
+{
+	struct list_head *list, *pos, *tmp;
+	struct sf_dir_buf *b;
+
+	list = &p->info_list;
+	list_for_each_safe(pos, tmp, list) {
+		b = list_entry(pos, struct sf_dir_buf, head);
+		b->entries = 0;
+		b->used = 0;
+		b->free = DIR_BUFFER_SIZE;
+	}
+}
+
+/**
+ * Create a new directory buffer descriptor.
+ * Return: Created sf_dir_info buffer, or NULL when malloc fails
+ */
+struct sf_dir_info *sf_dir_info_alloc(void)
+{
+	struct sf_dir_info *p;
+
+	p = kmalloc(sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return NULL;
+
+	INIT_LIST_HEAD(&p->info_list);
+	return p;
+}
+
+/* Search for an empty directory content buffer. */
+static struct sf_dir_buf *sf_get_empty_dir_buf(struct sf_dir_info *sf_d)
+{
+	struct list_head *list, *pos;
+
+	list = &sf_d->info_list;
+	list_for_each(pos, list) {
+		struct sf_dir_buf *b;
+
+		b = list_entry(pos, struct sf_dir_buf, head);
+		if (!b)
+			return NULL;
+
+		if (b->used == 0)
+			return b;
+	}
+
+	return NULL;
+}
+
+int sf_dir_read_all(struct sf_glob_info *sf_g, struct sf_inode_info *sf_i,
+		    struct sf_dir_info *sf_d, u64 handle)
+{
+	struct shfl_string *mask;
+	struct sf_dir_buf *b;
+	u32 entries, size;
+	void *buf;
+	int err;
+
+	err = sf_make_path(__func__, sf_i, "*", 1, &mask);
+	if (err)
+		return err;
+
+	/* vboxsf_dirinfo returns 1 on end of dir */
+	while (err == 0) {
+		b = sf_get_empty_dir_buf(sf_d);
+		if (!b) {
+			b = sf_dir_buf_alloc();
+			if (!b) {
+				err = -ENOMEM;
+				break;
+			}
+			list_add(&b->head, &sf_d->info_list);
+		}
+
+		buf = b->buf;
+		size = b->free;
+
+		err = vboxsf_dirinfo(sf_g->root, handle, mask, 0, 0,
+				     &size, buf, &entries);
+		if (err < 0)
+			break;
+
+		b->entries += entries;
+		b->free -= size;
+		b->used += size;
+	}
+
+	kfree(mask);
+
+	/* -EILSEQ means the host could not translate a filename, ignore */
+	if (err > 0 || err == -EILSEQ)
+		err = 0;
+
+	return err;
+}
diff --git a/fs/vboxsf/vboxsf_wrappers.c b/fs/vboxsf/vboxsf_wrappers.c
new file mode 100644
index 000000000000..3781ac466609
--- /dev/null
+++ b/fs/vboxsf/vboxsf_wrappers.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: (GPL-2.0 OR CDDL-1.0)
+/*
+ * Wrapper functions for the shfl host calls.
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vbox_err.h>
+#include <linux/vbox_utils.h>
+#include "vboxsf_wrappers.h"
+
+static u32 vboxsf_client_id;
+
+int vboxsf_connect(void)
+{
+	struct vbg_dev *gdev;
+	struct vmmdev_hgcm_service_location loc;
+	int err, vbox_status;
+
+	loc.type = VMMDEV_HGCM_LOC_LOCALHOST_EXISTING;
+	strcpy(loc.u.localhost.service_name, "VBoxSharedFolders");
+
+	gdev = vbg_get_gdev();
+	if (IS_ERR(gdev))
+		return VERR_NOT_SUPPORTED;	/* No guest-device */
+
+	err = vbg_hgcm_connect(gdev, &loc, &vboxsf_client_id, &vbox_status);
+	vbg_put_gdev(gdev);
+
+	return err ? err : vbg_status_code_to_errno(vbox_status);
+}
+
+void vboxsf_disconnect(void)
+{
+	struct vbg_dev *gdev;
+	int vbox_status;
+
+	gdev = vbg_get_gdev();
+	if (IS_ERR(gdev))
+		return;   /* guest-device is gone, already disconnected */
+
+	vbg_hgcm_disconnect(gdev, vboxsf_client_id, &vbox_status);
+	vbg_put_gdev(gdev);
+}
+
+static int vboxsf_call(u32 function, void *parms, u32 parm_count, int *status)
+{
+	struct vbg_dev *gdev;
+	int err, vbox_status;
+
+	gdev = vbg_get_gdev();
+	if (IS_ERR(gdev))
+		return VERR_DEV_IO_ERROR; /* guest-dev removed underneath us */
+
+	err = vbg_hgcm_call(gdev, vboxsf_client_id, function, U32_MAX,
+			    parms, parm_count, &vbox_status);
+	vbg_put_gdev(gdev);
+
+	if (err < 0)
+		return err;
+
+	if (status)
+		*status = vbox_status;
+
+	return vbg_status_code_to_errno(vbox_status);
+}
+
+int vboxsf_map_folder(struct shfl_string *folder_name, u32 *root)
+{
+	struct shfl_map_folder parms;
+	int err, status;
+
+	parms.path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL;
+	parms.path.u.pointer.size = shfl_string_buf_size(folder_name);
+	parms.path.u.pointer.u.linear_addr = (uintptr_t)folder_name;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = 0;
+
+	parms.delimiter.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.delimiter.u.value32 = '/';
+
+	parms.case_sensitive.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.case_sensitive.u.value32 = 1;
+
+	err = vboxsf_call(SHFL_FN_MAP_FOLDER, &parms, SHFL_CPARMS_MAP_FOLDER,
+			  &status);
+	if (err == -ENOSYS && status == VERR_NOT_IMPLEMENTED)
+		vbg_err("%s: Error host is too old\n", __func__);
+
+	*root = parms.root.u.value32;
+	return err;
+}
+
+int vboxsf_unmap_folder(u32 root)
+{
+	struct shfl_unmap_folder parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	return vboxsf_call(SHFL_FN_UNMAP_FOLDER, &parms,
+			   SHFL_CPARMS_UNMAP_FOLDER, NULL);
+}
+
+/**
+ * Create a new file or folder or open an existing one in a shared folder.
+ * Note this function always returns 0 / success unless an exceptional condition
+ * occurs - out of memory, invalid arguments, etc. If the file or folder could
+ * not be opened or created, create_parms->handle will be set to
+ * SHFL_HANDLE_NIL on return.  In this case the value in create_parms->result
+ * provides information as to why (e.g. SHFL_FILE_EXISTS), create_parms->result
+ * is also set on success as additional information.
+ * Return: 0 or negative errno value.
+ * @root	Root of the shared folder in which to create the file
+ * @parsed_path	The path of the file or folder relative to the shared folder
+ * @param	create_parms Parameters for file/folder creation.
+ */
+int vboxsf_create(u32 root, struct shfl_string *parsed_path,
+		  struct shfl_createparms *create_parms)
+{
+	struct shfl_create parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL;
+	parms.path.u.pointer.size = shfl_string_buf_size(parsed_path);
+	parms.path.u.pointer.u.linear_addr = (uintptr_t)parsed_path;
+
+	parms.parms.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL;
+	parms.parms.u.pointer.size = sizeof(struct shfl_createparms);
+	parms.parms.u.pointer.u.linear_addr = (uintptr_t)create_parms;
+
+	return vboxsf_call(SHFL_FN_CREATE, &parms, SHFL_CPARMS_CREATE, NULL);
+}
+
+int vboxsf_close(u32 root, u64 handle)
+{
+	struct shfl_close parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.handle.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.handle.u.value64 = handle;
+
+	return vboxsf_call(SHFL_FN_CLOSE, &parms, SHFL_CPARMS_CLOSE, NULL);
+}
+
+int vboxsf_remove(u32 root, struct shfl_string *parsed_path, u32 flags)
+{
+	struct shfl_remove parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.path.u.pointer.size = shfl_string_buf_size(parsed_path);
+	parms.path.u.pointer.u.linear_addr = (uintptr_t)parsed_path;
+
+	parms.flags.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.flags.u.value32 = flags;
+
+	return vboxsf_call(SHFL_FN_REMOVE, &parms, SHFL_CPARMS_REMOVE, NULL);
+}
+
+int vboxsf_rename(u32 root, struct shfl_string *src_path,
+		  struct shfl_string *dest_path, u32 flags)
+{
+	struct shfl_rename parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.src.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.src.u.pointer.size = shfl_string_buf_size(src_path);
+	parms.src.u.pointer.u.linear_addr = (uintptr_t)src_path;
+
+	parms.dest.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.dest.u.pointer.size = shfl_string_buf_size(dest_path);
+	parms.dest.u.pointer.u.linear_addr = (uintptr_t)dest_path;
+
+	parms.flags.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.flags.u.value32 = flags;
+
+	return vboxsf_call(SHFL_FN_RENAME, &parms, SHFL_CPARMS_RENAME, NULL);
+}
+
+int vboxsf_read(u32 root, u64 handle, u64 offset,
+		u32 *buf_len, u8 *buf, bool user)
+{
+	struct shfl_read parms;
+	int err;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.handle.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.handle.u.value64 = handle;
+	parms.offset.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.offset.u.value64 = offset;
+	parms.cb.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.cb.u.value32 = *buf_len;
+	if (user)
+		parms.buffer.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_OUT;
+	else
+		parms.buffer.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_OUT;
+	parms.buffer.u.pointer.size = *buf_len;
+	parms.buffer.u.pointer.u.linear_addr = (uintptr_t)buf;
+
+	err = vboxsf_call(SHFL_FN_READ, &parms, SHFL_CPARMS_READ, NULL);
+
+	*buf_len = parms.cb.u.value32;
+	return err;
+}
+
+int vboxsf_write(u32 root, u64 handle, u64 offset,
+		 u32 *buf_len, const u8 *buf, bool user)
+{
+	struct shfl_write parms;
+	int err;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.handle.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.handle.u.value64 = handle;
+	parms.offset.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.offset.u.value64 = offset;
+	parms.cb.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.cb.u.value32 = *buf_len;
+	if (user)
+		parms.buffer.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_IN;
+	else
+		parms.buffer.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.buffer.u.pointer.size = *buf_len;
+	parms.buffer.u.pointer.u.linear_addr = (uintptr_t)buf;
+
+	err = vboxsf_call(SHFL_FN_WRITE, &parms, SHFL_CPARMS_WRITE, NULL);
+
+	*buf_len = parms.cb.u.value32;
+	return err;
+}
+
+/* Returns 0 on success, 1 on end-of-dir, negative errno otherwise */
+int vboxsf_dirinfo(u32 root, u64 handle,
+		   struct shfl_string *parsed_path, u32 flags, u32 index,
+		   u32 *buf_len, struct shfl_dirinfo *buf, u32 *file_count)
+{
+	struct shfl_list parms;
+	int err, status;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.handle.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.handle.u.value64 = handle;
+	parms.flags.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.flags.u.value32 = flags;
+	parms.cb.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.cb.u.value32 = *buf_len;
+	parms.path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.path.u.pointer.size =
+	    parsed_path ? shfl_string_buf_size(parsed_path) : 0;
+	parms.path.u.pointer.u.linear_addr = (uintptr_t)parsed_path;
+
+	parms.buffer.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_OUT;
+	parms.buffer.u.pointer.size = *buf_len;
+	parms.buffer.u.pointer.u.linear_addr = (uintptr_t)buf;
+
+	parms.resume_point.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.resume_point.u.value32 = index;
+	parms.file_count.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.file_count.u.value32 = 0;	/* out parameter only */
+
+	err = vboxsf_call(SHFL_FN_LIST, &parms, SHFL_CPARMS_LIST, &status);
+	if (err == -ENODATA && status == VERR_NO_MORE_FILES)
+		err = 1;
+
+	*buf_len = parms.cb.u.value32;
+	*file_count = parms.file_count.u.value32;
+	return err;
+}
+
+int vboxsf_fsinfo(u32 root, u64 handle, u32 flags,
+		  u32 *buf_len, void *buf)
+{
+	struct shfl_information parms;
+	int err;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.handle.type = VMMDEV_HGCM_PARM_TYPE_64BIT;
+	parms.handle.u.value64 = handle;
+	parms.flags.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.flags.u.value32 = flags;
+	parms.cb.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.cb.u.value32 = *buf_len;
+	parms.info.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL;
+	parms.info.u.pointer.size = *buf_len;
+	parms.info.u.pointer.u.linear_addr = (uintptr_t)buf;
+
+	err = vboxsf_call(SHFL_FN_INFORMATION, &parms, SHFL_CPARMS_INFORMATION,
+			  NULL);
+
+	*buf_len = parms.cb.u.value32;
+	return err;
+}
+
+int vboxsf_readlink(u32 root, struct shfl_string *parsed_path,
+		    u32 buf_len, u8 *buf)
+{
+	struct shfl_readLink parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.path.u.pointer.size = shfl_string_buf_size(parsed_path);
+	parms.path.u.pointer.u.linear_addr = (uintptr_t)parsed_path;
+
+	parms.buffer.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_OUT;
+	parms.buffer.u.pointer.size = buf_len;
+	parms.buffer.u.pointer.u.linear_addr = (uintptr_t)buf;
+
+	return vboxsf_call(SHFL_FN_READLINK, &parms, SHFL_CPARMS_READLINK,
+			   NULL);
+}
+
+int vboxsf_symlink(u32 root, struct shfl_string *new_path,
+		   struct shfl_string *old_path, struct shfl_fsobjinfo *buf)
+{
+	struct shfl_symlink parms;
+
+	parms.root.type = VMMDEV_HGCM_PARM_TYPE_32BIT;
+	parms.root.u.value32 = root;
+
+	parms.new_path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.new_path.u.pointer.size = shfl_string_buf_size(new_path);
+	parms.new_path.u.pointer.u.linear_addr = (uintptr_t)new_path;
+
+	parms.old_path.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_IN;
+	parms.old_path.u.pointer.size = shfl_string_buf_size(old_path);
+	parms.old_path.u.pointer.u.linear_addr = (uintptr_t)old_path;
+
+	parms.info.type = VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL_OUT;
+	parms.info.u.pointer.size = sizeof(struct shfl_fsobjinfo);
+	parms.info.u.pointer.u.linear_addr = (uintptr_t)buf;
+
+	return vboxsf_call(SHFL_FN_SYMLINK, &parms, SHFL_CPARMS_SYMLINK, NULL);
+}
+
+int vboxsf_set_utf8(void)
+{
+	return vboxsf_call(SHFL_FN_SET_UTF8, NULL, 0, NULL);
+}
+
+int vboxsf_set_symlinks(void)
+{
+	return vboxsf_call(SHFL_FN_SET_SYMLINKS, NULL, 0, NULL);
+}
diff --git a/fs/vboxsf/vboxsf_wrappers.h b/fs/vboxsf/vboxsf_wrappers.h
new file mode 100644
index 000000000000..9abca9aea6a9
--- /dev/null
+++ b/fs/vboxsf/vboxsf_wrappers.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR CDDL-1.0) */
+/*
+ * Protype declarations for the wrapper functions for the shfl host calls.
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#ifndef VBOXSF_WRAPPERS_H
+#define VBOXSF_WRAPPERS_H
+
+#include "shfl_hostintf.h"
+
+int vboxsf_connect(void);
+void vboxsf_disconnect(void);
+
+int vboxsf_create(u32 root, struct shfl_string *parsed_path,
+		  struct shfl_createparms *create_parms);
+
+int vboxsf_close(u32 root, u64 handle);
+int vboxsf_remove(u32 root, struct shfl_string *parsed_path, u32 flags);
+int vboxsf_rename(u32 root, struct shfl_string *src_path,
+		  struct shfl_string *dest_path, u32 flags);
+
+int vboxsf_read(u32 root, u64 handle, u64 offset,
+		u32 *buf_len, u8 *buf, bool user);
+int vboxsf_write(u32 root, u64 handle, u64 offset,
+		 u32 *buf_len, const u8 *buf, bool user);
+
+int vboxsf_dirinfo(u32 root, u64 handle,
+		   struct shfl_string *parsed_path, u32 flags, u32 index,
+		   u32 *buf_len, struct shfl_dirinfo *buf, u32 *file_count);
+int vboxsf_fsinfo(u32 root, u64 handle, u32 flags,
+		  u32 *buf_len, void *buf);
+
+int vboxsf_map_folder(struct shfl_string *folder_name, u32 *root);
+int vboxsf_unmap_folder(u32 root);
+
+int vboxsf_readlink(u32 root, struct shfl_string *parsed_path,
+		    u32 buf_len, u8 *buf);
+int vboxsf_symlink(u32 root, struct shfl_string *new_path,
+		   struct shfl_string *old_path, struct shfl_fsobjinfo *buf);
+
+int vboxsf_set_utf8(void);
+int vboxsf_set_symlinks(void);
+
+#endif
diff --git a/fs/vboxsf/vfsmod.h b/fs/vboxsf/vfsmod.h
new file mode 100644
index 000000000000..29dd69aacfdc
--- /dev/null
+++ b/fs/vboxsf/vfsmod.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * VirtualBox Guest Shared Folders support: module header.
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#ifndef VFSMOD_H
+#define VFSMOD_H
+
+#include <linux/backing-dev.h>
+#include <linux/version.h>
+#include "vboxsf_wrappers.h"
+
+#define DIR_BUFFER_SIZE SZ_16K
+
+/* The cast is to prevent assignment of void * to pointers of arbitrary type */
+#define GET_GLOB_INFO(sb)       ((struct sf_glob_info *)(sb)->s_fs_info)
+#define SET_GLOB_INFO(sb, sf_g) ((sb)->s_fs_info = (sf_g))
+#define GET_INODE_INFO(i)       container_of(i, struct sf_inode_info, vfs_inode)
+#define GET_F_DENTRY(f)         (f->f_path.dentry)
+
+/* per-shared folder information */
+struct sf_glob_info {
+	u32 root;
+	struct nls_table *nls;
+	int ttl;
+	int uid;
+	int gid;
+	int dmode;
+	int fmode;
+	int dmask;
+	int fmask;
+};
+
+/* per-inode information */
+struct sf_inode_info {
+	/* which file */
+	struct shfl_string *path;
+	/* some information was changed, update data on next revalidate */
+	int force_restat;
+	/*
+	 * directory content changed, update the whole directory on next
+	 * sf_getdent
+	 */
+	int force_reread;
+	/* file structure, only valid between open() and release() */
+	struct file *file;
+	/*
+	 * handle valid if a file was created with sf_create_aux until it
+	 * will be opened with sf_reg_open()
+	 */
+	u64 handle;
+	/* The VFS inode struct */
+	struct inode vfs_inode;
+};
+
+struct sf_dir_info {
+	struct list_head info_list;
+};
+
+struct sf_dir_buf {
+	size_t entries;
+	size_t free;
+	size_t used;
+	void *buf;
+	struct list_head head;
+};
+
+struct sf_reg_info {
+	u64 handle;
+};
+
+/* globals */
+extern const struct inode_operations sf_dir_iops;
+extern const struct inode_operations sf_lnk_iops;
+extern const struct inode_operations sf_reg_iops;
+extern const struct file_operations sf_dir_fops;
+extern const struct file_operations sf_reg_fops;
+extern const struct address_space_operations sf_reg_aops;
+
+void sf_init_inode(struct sf_glob_info *sf_g, struct inode *inode,
+		   const struct shfl_fsobjinfo *info);
+int sf_stat(const char *caller, struct sf_glob_info *sf_g,
+	    struct shfl_string *path, struct shfl_fsobjinfo *result,
+	    int ok_to_fail);
+int sf_inode_revalidate(struct dentry *dentry);
+int sf_getattr(const struct path *path, struct kstat *kstat,
+	       u32 request_mask, unsigned int query_flags);
+int sf_setattr(struct dentry *dentry, struct iattr *iattr);
+int sf_path_from_dentry(const char *caller, struct sf_glob_info *sf_g,
+			struct sf_inode_info *sf_i,
+			struct dentry *dentry, struct shfl_string **result);
+int sf_nlscpy(struct sf_glob_info *sf_g, char *name,
+	      size_t name_bound_len, const unsigned char *utf8_name,
+	      size_t utf8_len);
+void sf_dir_info_free(struct sf_dir_info *p);
+void sf_dir_info_empty(struct sf_dir_info *p);
+struct sf_dir_info *sf_dir_info_alloc(void);
+int sf_dir_read_all(struct sf_glob_info *sf_g,
+		    struct sf_inode_info *sf_i, struct sf_dir_info *sf_d,
+		    u64 handle);
+
+#endif
diff --git a/include/uapi/linux/vbsfmount.h b/include/uapi/linux/vbsfmount.h
new file mode 100644
index 000000000000..21aa546a2a64
--- /dev/null
+++ b/include/uapi/linux/vbsfmount.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2006-2016 Oracle Corporation
+ *
+ * VirtualBox Guest Shared Folders: mount(2) parameter structure.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef VBFS_MOUNT_H
+#define VBFS_MOUNT_H
+
+/* Linux constraints the size of data mount argument to PAGE_SIZE - 1. */
+#define MAX_HOST_NAME  256
+#define MAX_NLS_NAME    32
+
+#define VBSF_MOUNT_SIGNATURE_BYTE_0 ('\377')
+#define VBSF_MOUNT_SIGNATURE_BYTE_1 ('\376')
+#define VBSF_MOUNT_SIGNATURE_BYTE_2 ('\375')
+
+struct vbsf_mount_info_new {
+	/*
+	 * The old version of the mount_info struct started with a
+	 * char name[MAX_HOST_NAME] field, where name cannot be '\0'.
+	 * So the new version of the mount_info struct starts with a
+	 * nullchar field which is always 0 so that we can detect and
+	 * reject the old structure being passed.
+	 */
+	char nullchar;
+	char signature[3];	/* signature */
+	int length;		/* length of the whole structure */
+	char name[MAX_HOST_NAME];	/* share name */
+	char nls_name[MAX_NLS_NAME];	/* name of an I/O charset */
+	int uid;		/* user ID for all entries, default 0=root */
+	int gid;		/* group ID for all entries, default 0=root */
+	int ttl;		/* time to live */
+	int dmode;		/* mode for directories if != 0xffffffff */
+	int fmode;		/* mode for regular files if != 0xffffffff */
+	int dmask;		/* umask applied to directories */
+	int fmask;		/* umask applied to regular files */
+};
+
+struct vbsf_mount_opts {
+	int uid;
+	int gid;
+	int ttl;
+	int dmode;
+	int fmode;
+	int dmask;
+	int fmask;
+	int ronly;
+	int sloppy;
+	int noexec;
+	int nodev;
+	int nosuid;
+	int remount;
+	char nls_name[MAX_NLS_NAME];
+	char *convertcp;
+};
+
+#endif /* vbsfmount.h */
-- 
2.14.3

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 17:51 ` [PATCH v2] " Hans de Goede
@ 2018-01-15 17:55   ` Christoph Hellwig
  2018-01-15 18:01     ` Hans de Goede
  2018-01-15 19:32   ` Amir Goldstein
  2018-01-15 22:36   ` Al Viro
  2 siblings, 1 reply; 11+ messages in thread
From: Christoph Hellwig @ 2018-01-15 17:55 UTC (permalink / raw)
  To: Hans de Goede
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer,
	Alexander Viro, Larry Finger, Christoph Hellwig, linux-kernel,
	linux-fsdevel

The mount uabi stuff is a red flag - all filesystems should use
text options only these days.  From a 20 second view it seems like
this one does that, and the header can just be removed, but if not
a lot more work will be needed.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 17:55   ` Christoph Hellwig
@ 2018-01-15 18:01     ` Hans de Goede
  0 siblings, 0 replies; 11+ messages in thread
From: Hans de Goede @ 2018-01-15 18:01 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer,
	Alexander Viro, Larry Finger, linux-kernel, linux-fsdevel

Hi,

On 15-01-18 18:55, Christoph Hellwig wrote:
> The mount uabi stuff is a red flag - all filesystems should use
> text options only these days.  From a 20 second view it seems like
> this one does that, and the header can just be removed, but if not
> a lot more work will be needed.

Thank you for the quick feedback. I already expected this would be a
problem, but I kept it around for 100% compatibility with the out of
tree version of the vboxsf driver. I will fix this for v3 and coordinate
with vbox upstream what to do about the compatibility issue.

Regards,

Hans

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 17:51 ` [PATCH v2] " Hans de Goede
  2018-01-15 17:55   ` Christoph Hellwig
@ 2018-01-15 19:32   ` Amir Goldstein
  2018-01-15 19:41     ` Hans de Goede
  2018-01-15 22:36   ` Al Viro
  2 siblings, 1 reply; 11+ messages in thread
From: Amir Goldstein @ 2018-01-15 19:32 UTC (permalink / raw)
  To: Hans de Goede
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer,
	Alexander Viro, Larry Finger, Christoph Hellwig, linux-kernel,
	linux-fsdevel

On Mon, Jan 15, 2018 at 7:51 PM, Hans de Goede <hdegoede@redhat.com> wrote:
> VirtualBox hosts can share folders with guests, this commit adds a
> VFS driver implementing the Linux-guest side of this, allowing folders
> exported by the host to be mounted under Linux.
>
> This driver depends on the guest <-> host IPC functions exported by
> the vboxguest driver.
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  fs/Kconfig                     |   1 +
>  fs/Makefile                    |   1 +
>  fs/vboxsf/Kconfig              |   9 +
>  fs/vboxsf/Makefile             |   3 +
>  fs/vboxsf/dir.c                | 648 +++++++++++++++++++++++++++++
>  fs/vboxsf/file.c               | 416 +++++++++++++++++++
>  fs/vboxsf/shfl_hostintf.h      | 919 +++++++++++++++++++++++++++++++++++++++++
>  fs/vboxsf/super.c              | 430 +++++++++++++++++++
>  fs/vboxsf/utils.c              | 589 ++++++++++++++++++++++++++
>  fs/vboxsf/vboxsf_wrappers.c    | 365 ++++++++++++++++
>  fs/vboxsf/vboxsf_wrappers.h    |  46 +++
>  fs/vboxsf/vfsmod.h             | 104 +++++
>  include/uapi/linux/vbsfmount.h |  62 +++
>  13 files changed, 3593 insertions(+)
>  create mode 100644 fs/vboxsf/Kconfig
>  create mode 100644 fs/vboxsf/Makefile
>  create mode 100644 fs/vboxsf/dir.c
>  create mode 100644 fs/vboxsf/file.c
>  create mode 100644 fs/vboxsf/shfl_hostintf.h
>  create mode 100644 fs/vboxsf/super.c
>  create mode 100644 fs/vboxsf/utils.c
>  create mode 100644 fs/vboxsf/vboxsf_wrappers.c
>  create mode 100644 fs/vboxsf/vboxsf_wrappers.h
>  create mode 100644 fs/vboxsf/vfsmod.h
>  create mode 100644 include/uapi/linux/vbsfmount.h

A MAINTAINERS entry seems in order.

>
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 7aee6d699fd6..7f80ad1cf591 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -248,6 +248,7 @@ source "fs/pstore/Kconfig"
>  source "fs/sysv/Kconfig"
>  source "fs/ufs/Kconfig"
>  source "fs/exofs/Kconfig"
> +source "fs/vboxsf/Kconfig"
>
>  endif # MISC_FILESYSTEMS
>
> diff --git a/fs/Makefile b/fs/Makefile
> index ef772f1eaff8..3057830f112a 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -129,3 +129,4 @@ obj-y                               += exofs/ # Multiple modules
>  obj-$(CONFIG_CEPH_FS)          += ceph/
>  obj-$(CONFIG_PSTORE)           += pstore/
>  obj-$(CONFIG_EFIVAR_FS)                += efivarfs/
> +obj-$(CONFIG_VBOXSF_FS)                += vboxsf/
> diff --git a/fs/vboxsf/Kconfig b/fs/vboxsf/Kconfig
> new file mode 100644
> index 000000000000..620e2232969c
> --- /dev/null
> +++ b/fs/vboxsf/Kconfig
> @@ -0,0 +1,9 @@
> +config VBOXSF_FS
> +       tristate "VirtualBox guest shared folder (vboxsf) support"


Don't know if you noticed, but calling your filesystem vboxsf
is quite odd name among other XXXfs beasts.
Will it be an option to re-brand this as vboxfs?
Even if it is too late or too much of a hustle to change the user visible
file_system_type name, I think changing the internal name is worth it.

The other thing is if you can help it to avoid the short 'sf_' prefix and
use a longer prefix even for static functions, something like vbsf_ or
vbfs_ that would be better.

Cheers,
Amir.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 19:32   ` Amir Goldstein
@ 2018-01-15 19:41     ` Hans de Goede
  2018-01-15 20:22       ` Amir Goldstein
  0 siblings, 1 reply; 11+ messages in thread
From: Hans de Goede @ 2018-01-15 19:41 UTC (permalink / raw)
  To: Amir Goldstein
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer,
	Alexander Viro, Larry Finger, Christoph Hellwig, linux-kernel,
	linux-fsdevel

Hi,

On 15-01-18 20:32, Amir Goldstein wrote:
> On Mon, Jan 15, 2018 at 7:51 PM, Hans de Goede <hdegoede@redhat.com> wrote:
>> VirtualBox hosts can share folders with guests, this commit adds a
>> VFS driver implementing the Linux-guest side of this, allowing folders
>> exported by the host to be mounted under Linux.
>>
>> This driver depends on the guest <-> host IPC functions exported by
>> the vboxguest driver.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>   fs/Kconfig                     |   1 +
>>   fs/Makefile                    |   1 +
>>   fs/vboxsf/Kconfig              |   9 +
>>   fs/vboxsf/Makefile             |   3 +
>>   fs/vboxsf/dir.c                | 648 +++++++++++++++++++++++++++++
>>   fs/vboxsf/file.c               | 416 +++++++++++++++++++
>>   fs/vboxsf/shfl_hostintf.h      | 919 +++++++++++++++++++++++++++++++++++++++++
>>   fs/vboxsf/super.c              | 430 +++++++++++++++++++
>>   fs/vboxsf/utils.c              | 589 ++++++++++++++++++++++++++
>>   fs/vboxsf/vboxsf_wrappers.c    | 365 ++++++++++++++++
>>   fs/vboxsf/vboxsf_wrappers.h    |  46 +++
>>   fs/vboxsf/vfsmod.h             | 104 +++++
>>   include/uapi/linux/vbsfmount.h |  62 +++
>>   13 files changed, 3593 insertions(+)
>>   create mode 100644 fs/vboxsf/Kconfig
>>   create mode 100644 fs/vboxsf/Makefile
>>   create mode 100644 fs/vboxsf/dir.c
>>   create mode 100644 fs/vboxsf/file.c
>>   create mode 100644 fs/vboxsf/shfl_hostintf.h
>>   create mode 100644 fs/vboxsf/super.c
>>   create mode 100644 fs/vboxsf/utils.c
>>   create mode 100644 fs/vboxsf/vboxsf_wrappers.c
>>   create mode 100644 fs/vboxsf/vboxsf_wrappers.h
>>   create mode 100644 fs/vboxsf/vfsmod.h
>>   create mode 100644 include/uapi/linux/vbsfmount.h
> 
> A MAINTAINERS entry seems in order.

Ack and thank you for the feedback.

>> diff --git a/fs/Kconfig b/fs/Kconfig
>> index 7aee6d699fd6..7f80ad1cf591 100644
>> --- a/fs/Kconfig
>> +++ b/fs/Kconfig
>> @@ -248,6 +248,7 @@ source "fs/pstore/Kconfig"
>>   source "fs/sysv/Kconfig"
>>   source "fs/ufs/Kconfig"
>>   source "fs/exofs/Kconfig"
>> +source "fs/vboxsf/Kconfig"
>>
>>   endif # MISC_FILESYSTEMS
>>
>> diff --git a/fs/Makefile b/fs/Makefile
>> index ef772f1eaff8..3057830f112a 100644
>> --- a/fs/Makefile
>> +++ b/fs/Makefile
>> @@ -129,3 +129,4 @@ obj-y                               += exofs/ # Multiple modules
>>   obj-$(CONFIG_CEPH_FS)          += ceph/
>>   obj-$(CONFIG_PSTORE)           += pstore/
>>   obj-$(CONFIG_EFIVAR_FS)                += efivarfs/
>> +obj-$(CONFIG_VBOXSF_FS)                += vboxsf/
>> diff --git a/fs/vboxsf/Kconfig b/fs/vboxsf/Kconfig
>> new file mode 100644
>> index 000000000000..620e2232969c
>> --- /dev/null
>> +++ b/fs/vboxsf/Kconfig
>> @@ -0,0 +1,9 @@
>> +config VBOXSF_FS
>> +       tristate "VirtualBox guest shared folder (vboxsf) support"
> 
> 
> Don't know if you noticed, but calling your filesystem vboxsf
> is quite odd name among other XXXfs beasts.

Yes I noticed, note I'm only the guy pushing this upstream this code
has a long out-of-tree history. FWIW the sf stand for "shared folder"

> Will it be an option to re-brand this as vboxfs?
> Even if it is too late or too much of a hustle to change the user visible
> file_system_type name, I think changing the internal name is worth it.

We can quite definitely not change the user-visible name, the mount
arg changes Christoph Hellwig has requested are tricky enough wrt
compatibility with the out-of-tree version most users use atm.

The users will need updated userspace tools to deal with the mount arg
changes, but that is as easy as checking for -EINVAL and trying again
with the new style string args. But figuring out the right fstype name
is rather more tricky and the mount binary name has been mount.vboxsf
for ages...  So I would really like to keep the file_system_type name
as vboxsf, at which point it seems counter-productive to me to rename
the files / kernel-mode to vboxfs.

> The other thing is if you can help it to avoid the short 'sf_' prefix and
> use a longer prefix even for static functions, something like vbsf_ or
> vbfs_ that would be better.

Agreed, I did not take the buildin use-case where everything gets linked
into a single binary into account, will fix for v3.

Regards,

Hans

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 19:41     ` Hans de Goede
@ 2018-01-15 20:22       ` Amir Goldstein
  0 siblings, 0 replies; 11+ messages in thread
From: Amir Goldstein @ 2018-01-15 20:22 UTC (permalink / raw)
  To: Hans de Goede
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer,
	Alexander Viro, Larry Finger, Christoph Hellwig, linux-kernel,
	linux-fsdevel

On Mon, Jan 15, 2018 at 9:41 PM, Hans de Goede <hdegoede@redhat.com> wrote:
> Hi,
>
>
> On 15-01-18 20:32, Amir Goldstein wrote:
>>
>> On Mon, Jan 15, 2018 at 7:51 PM, Hans de Goede <hdegoede@redhat.com>
>> wrote:
>>>
>>> VirtualBox hosts can share folders with guests, this commit adds a
>>> VFS driver implementing the Linux-guest side of this, allowing folders
>>> exported by the host to be mounted under Linux.
>>>
>>> This driver depends on the guest <-> host IPC functions exported by
>>> the vboxguest driver.
>>>
>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>> ---
>>>   fs/Kconfig                     |   1 +
>>>   fs/Makefile                    |   1 +
>>>   fs/vboxsf/Kconfig              |   9 +
>>>   fs/vboxsf/Makefile             |   3 +
>>>   fs/vboxsf/dir.c                | 648 +++++++++++++++++++++++++++++
>>>   fs/vboxsf/file.c               | 416 +++++++++++++++++++
>>>   fs/vboxsf/shfl_hostintf.h      | 919
>>> +++++++++++++++++++++++++++++++++++++++++
>>>   fs/vboxsf/super.c              | 430 +++++++++++++++++++
>>>   fs/vboxsf/utils.c              | 589 ++++++++++++++++++++++++++
>>>   fs/vboxsf/vboxsf_wrappers.c    | 365 ++++++++++++++++
>>>   fs/vboxsf/vboxsf_wrappers.h    |  46 +++
>>>   fs/vboxsf/vfsmod.h             | 104 +++++
>>>   include/uapi/linux/vbsfmount.h |  62 +++
>>>   13 files changed, 3593 insertions(+)
>>>   create mode 100644 fs/vboxsf/Kconfig
>>>   create mode 100644 fs/vboxsf/Makefile
>>>   create mode 100644 fs/vboxsf/dir.c
>>>   create mode 100644 fs/vboxsf/file.c
>>>   create mode 100644 fs/vboxsf/shfl_hostintf.h
>>>   create mode 100644 fs/vboxsf/super.c
>>>   create mode 100644 fs/vboxsf/utils.c
>>>   create mode 100644 fs/vboxsf/vboxsf_wrappers.c
>>>   create mode 100644 fs/vboxsf/vboxsf_wrappers.h
>>>   create mode 100644 fs/vboxsf/vfsmod.h
>>>   create mode 100644 include/uapi/linux/vbsfmount.h
>>
>>
[...]
>>> +++ b/fs/vboxsf/Kconfig
>>> @@ -0,0 +1,9 @@
>>> +config VBOXSF_FS
>>> +       tristate "VirtualBox guest shared folder (vboxsf) support"
>>
>>
>>
>> Don't know if you noticed, but calling your filesystem vboxsf
>> is quite odd name among other XXXfs beasts.
>
>
> Yes I noticed, note I'm only the guy pushing this upstream this code
> has a long out-of-tree history. FWIW the sf stand for "shared folder"
>
>> Will it be an option to re-brand this as vboxfs?
>> Even if it is too late or too much of a hustle to change the user visible
>> file_system_type name, I think changing the internal name is worth it.
>
>
> We can quite definitely not change the user-visible name, the mount
> arg changes Christoph Hellwig has requested are tricky enough wrt
> compatibility with the out-of-tree version most users use atm.
>
> The users will need updated userspace tools to deal with the mount arg
> changes, but that is as easy as checking for -EINVAL and trying again
> with the new style string args. But figuring out the right fstype name
> is rather more tricky and the mount binary name has been mount.vboxsf
> for ages...  So I would really like to keep the file_system_type name
> as vboxsf, at which point it seems counter-productive to me to rename
> the files / kernel-mode to vboxfs.
>

Well, its up to you and whoever merges this code, but I don't find this
rename counter-productive at all. Isn't the idea behind becoming an in-tree
fs, conforming to the way we do things in-the-tree?

Someone at Oracle once made a decision sometime in the past when that
code was out of tree and not among other fs without conforming to in-tree
standards. That decision affects the user visible fs name and I wasn't
suggesting to change that. That is what MODULE_ALIAS_FS is for.
But there is not really a good reason to carry the baggage of this decision
into the tree.

I don't know, maybe it's just me...

Cheers,
Amir.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 17:51 ` [PATCH v2] " Hans de Goede
  2018-01-15 17:55   ` Christoph Hellwig
  2018-01-15 19:32   ` Amir Goldstein
@ 2018-01-15 22:36   ` Al Viro
  2018-01-16 10:15     ` Hans de Goede
  2 siblings, 1 reply; 11+ messages in thread
From: Al Viro @ 2018-01-15 22:36 UTC (permalink / raw)
  To: Hans de Goede
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer, Larry Finger,
	Christoph Hellwig, linux-kernel, linux-fsdevel

* what hch said about mount options.  Get rid of that before the thing
  goes into mainline.

* all "inode = GET_F_DENTRY(f)->d_inode;" are complete BS; it's called
  file_inode(f).  Kill GET_F_DENTRY() off and be done with that.

* your ->rename() can race with ->get_link().  Look at the place where
  the former reassigns ->path and frees the old value and think what
  happens if the latter is called just prior to that kfree().

* the same goes for sf_inode_revalidate() vs. rename().

* just what happens to ->path of inode when e.g. its grandparent
  directory is renamed?

* AFAICS, you consider all negative dentries invalid.  Why do you even
  hash them, then?

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-15 22:36   ` Al Viro
@ 2018-01-16 10:15     ` Hans de Goede
  2018-01-17  3:19       ` Al Viro
  0 siblings, 1 reply; 11+ messages in thread
From: Hans de Goede @ 2018-01-16 10:15 UTC (permalink / raw)
  To: Al Viro
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer, Larry Finger,
	Christoph Hellwig, linux-kernel, linux-fsdevel

Hi Al,

Thank you for the quick review.

On 15-01-18 23:36, Al Viro wrote:
> * what hch said about mount options.  Get rid of that before the thing
>    goes into mainline.

Ack.

> * all "inode = GET_F_DENTRY(f)->d_inode;" are complete BS; it's called
>    file_inode(f).  Kill GET_F_DENTRY() off and be done with that.

Ok, will fix.

> * your ->rename() can race with ->get_link().  Look at the place where
>    the former reassigns ->path and frees the old value and think what
>    happens if the latter is called just prior to that kfree().
> 
> * the same goes for sf_inode_revalidate() vs. rename().
> 
> * just what happens to ->path of inode when e.g. its grandparent
>    directory is renamed?

Can I summarize all 3 above with: Caching the path is a bad idea and
instead the code should always look up the name from e.g. file->f_path.dentry ?

> * AFAICS, you consider all negative dentries invalid.  Why do you even
>    hash them, then?

I'm afraid I'm not entirely following you. Note I've no experience with fs
code prior to this. Also I'm not the original author of this code, this
code started as part of the out-of-tree kernel modules used by the
VirtualBox guest-additions. I've been working on cleaning these modules up
and then mainlinging them (there are 3 of them, this is the last).

Note I believe that this code is based on the fs/hostfs code.

Can you reword your question keeping my lack of experience wrt fs code
in mind ?

Regards,

Hans

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-16 10:15     ` Hans de Goede
@ 2018-01-17  3:19       ` Al Viro
  2018-01-17 10:45         ` Hans de Goede
  0 siblings, 1 reply; 11+ messages in thread
From: Al Viro @ 2018-01-17  3:19 UTC (permalink / raw)
  To: Hans de Goede
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer, Larry Finger,
	Christoph Hellwig, linux-kernel, linux-fsdevel

On Tue, Jan 16, 2018 at 11:15:15AM +0100, Hans de Goede wrote:
> > * your ->rename() can race with ->get_link().  Look at the place where
> >    the former reassigns ->path and frees the old value and think what
> >    happens if the latter is called just prior to that kfree().
> > 
> > * the same goes for sf_inode_revalidate() vs. rename().
> > 
> > * just what happens to ->path of inode when e.g. its grandparent
> >    directory is renamed?
> 
> Can I summarize all 3 above with: Caching the path is a bad idea and
> instead the code should always look up the name from e.g. file->f_path.dentry ?

Caching the path is very likely to be a bad idea.  OTOH, caching conversions
of individual components, which appear to be completely independent of
any inodes, might be useful, especially if you attach the results to dentries
instead of inodes.  That way you only do nls shite on lookups.  Concatenation
of pieces into the pathname is probably best done later and in each case
we really want to decide what to do with racing renames of ancestors *DURING*
vboxsf_...() primitives.  We can be clever and careful while building the
pathname, but what's to prevent it going stale just as we'd formed the damn
string and started to do whatever it was we'd formed it for and what happens
in case of such races?

> > * AFAICS, you consider all negative dentries invalid.  Why do you even
> >    hash them, then?
> 
> I'm afraid I'm not entirely following you. Note I've no experience with fs
> code prior to this. Also I'm not the original author of this code, this
> code started as part of the out-of-tree kernel modules used by the
> VirtualBox guest-additions. I've been working on cleaning these modules up
> and then mainlinging them (there are 3 of them, this is the last).
> 
> Note I believe that this code is based on the fs/hostfs code.
> 
> Can you reword your question keeping my lack of experience wrt fs code
> in mind ?

Your ->d_revalidate() flat-out returns 0 on negative dentries.  Which
means "consider them invalid when found by dcache lookup".  So what's
the point of hashing them at all?  Note that the right answer might
very well be "build a pathname anyway, stat the sucker and consider
ENOENT as it's still valid"...

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2] fs: Add VirtualBox guest shared folder (vboxsf) support
  2018-01-17  3:19       ` Al Viro
@ 2018-01-17 10:45         ` Hans de Goede
  0 siblings, 0 replies; 11+ messages in thread
From: Hans de Goede @ 2018-01-17 10:45 UTC (permalink / raw)
  To: Al Viro
  Cc: Arnd Bergmann, Greg Kroah-Hartman, Michael Thayer, Larry Finger,
	Christoph Hellwig, linux-kernel, linux-fsdevel

Hi,

On 17-01-18 04:19, Al Viro wrote:
> On Tue, Jan 16, 2018 at 11:15:15AM +0100, Hans de Goede wrote:
>>> * your ->rename() can race with ->get_link().  Look at the place where
>>>     the former reassigns ->path and frees the old value and think what
>>>     happens if the latter is called just prior to that kfree().
>>>
>>> * the same goes for sf_inode_revalidate() vs. rename().
>>>
>>> * just what happens to ->path of inode when e.g. its grandparent
>>>     directory is renamed?
>>
>> Can I summarize all 3 above with: Caching the path is a bad idea and
>> instead the code should always look up the name from e.g. file->f_path.dentry ?
> 
> Caching the path is very likely to be a bad idea.  OTOH, caching conversions
> of individual components, which appear to be completely independent of
> any inodes, might be useful, especially if you attach the results to dentries
> instead of inodes.  That way you only do nls shite on lookups.  Concatenation
> of pieces into the pathname is probably best done later and in each case
> we really want to decide what to do with racing renames of ancestors *DURING*
> vboxsf_...() primitives.  We can be clever and careful while building the
> pathname, but what's to prevent it going stale just as we'd formed the damn
> string and started to do whatever it was we'd formed it for and what happens
> in case of such races?

vboxsf really works like a networkfs wrt this, for any calls to the hypervisor
taking a path (rather then a handle) if we race and we loose then the hypervisor
will simply return to use which a file-does-not-exist (at the now no longer
valid path) error.

There are 2 types of races here:
1) Racing with accesses to the shared-folder outside of the guest, there
is really nothing we can do here and in this case just reporting the error to
the higher layers is the right thing to do IMHO

2) Racing with other accesses inside the guest, so we do something which
requires a path and some of the parents may e.g. be renamed from inside the
guest while we do this. I'm tempted to just also report the error returned
by the host here. Since 1. is unavoidable anyways treating them both the
same seems easiest.

Ideally 2 should never happen at all and all calls which fall under 2
would work with a handle, but at least re-reading a dir, which we do when
a file inside it gets renamed, requires closing and opening the handle.

The call to get entries of the dir has an index argument, but the
implementation in the hypervisor has:

     Assert(*pIndex == 0);

And uses hypervisor private data attached to the handle to actually
track where we are in the listing :|

>>> * AFAICS, you consider all negative dentries invalid.  Why do you even
>>>     hash them, then?
>>
>> I'm afraid I'm not entirely following you. Note I've no experience with fs
>> code prior to this. Also I'm not the original author of this code, this
>> code started as part of the out-of-tree kernel modules used by the
>> VirtualBox guest-additions. I've been working on cleaning these modules up
>> and then mainlinging them (there are 3 of them, this is the last).
>>
>> Note I believe that this code is based on the fs/hostfs code.
>>
>> Can you reword your question keeping my lack of experience wrt fs code
>> in mind ?
> 
> Your ->d_revalidate() flat-out returns 0 on negative dentries.  Which
> means "consider them invalid when found by dcache lookup".  So what's
> the point of hashing them at all?  Note that the right answer might
> very well be "build a pathname anyway, stat the sucker and consider
> ENOENT as it's still valid"...

Ah ok, so reading up a bit on this I see now that a "negative"
dentry is a dentry for an unlinked filename, so without an inode linked
to it (dentry->inode is NULL).

As you suggest building the path and check if it has not been recreated
underneath us with a stat seems like the best solution here.

Regards,

Hans

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2018-01-17 10:45 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-01-15 17:51 [PATCH v2 0/1] fs: Add VirtualBox guest shared folder (vboxsf) support Hans de Goede
2018-01-15 17:51 ` [PATCH v2] " Hans de Goede
2018-01-15 17:55   ` Christoph Hellwig
2018-01-15 18:01     ` Hans de Goede
2018-01-15 19:32   ` Amir Goldstein
2018-01-15 19:41     ` Hans de Goede
2018-01-15 20:22       ` Amir Goldstein
2018-01-15 22:36   ` Al Viro
2018-01-16 10:15     ` Hans de Goede
2018-01-17  3:19       ` Al Viro
2018-01-17 10:45         ` Hans de Goede

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