Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

20 files changed, 6450 insertions, 0 deletions

diff --git a/fs/9p/Kconfig b/fs/9p/Kconfig
new file mode 100644
index 000000000..d7bc93447
--- /dev/null
+++ b/fs/9p/Kconfig
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config 9P_FS
+	tristate "Plan 9 Resource Sharing Support (9P2000)"
+	depends on INET && NET_9P
+	select NETFS_SUPPORT
+	help
+	  If you say Y here, you will get experimental support for
+	  Plan 9 resource sharing via the 9P2000 protocol.
+
+	  See <http://v9fs.sf.net> for more information.
+
+	  If unsure, say N.
+
+if 9P_FS
+config 9P_FSCACHE
+	bool "Enable 9P client caching support"
+	depends on 9P_FS=m && FSCACHE || 9P_FS=y && FSCACHE=y
+	help
+	  Choose Y here to enable persistent, read-only local
+	  caching support for 9p clients using FS-Cache
+
+
+config 9P_FS_POSIX_ACL
+	bool "9P POSIX Access Control Lists"
+	select FS_POSIX_ACL
+	help
+	  POSIX Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  If you don't know what Access Control Lists are, say N
+
+endif
+
+
+config 9P_FS_SECURITY
+	bool "9P Security Labels"
+	depends on 9P_FS
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux.  This option
+	  enables an extended attribute handler for file security
+	  labels in the 9P filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.
diff --git a/fs/9p/Makefile b/fs/9p/Makefile
new file mode 100644
index 000000000..e7800a5c7
--- /dev/null
+++ b/fs/9p/Makefile
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_9P_FS) := 9p.o
+
+9p-objs := \
+	vfs_super.o \
+	vfs_inode.o \
+	vfs_inode_dotl.o \
+	vfs_addr.o \
+	vfs_file.o \
+	vfs_dir.o \
+	vfs_dentry.o \
+	v9fs.o \
+	fid.o  \
+	xattr.o
+
+9p-$(CONFIG_9P_FSCACHE) += cache.o
+9p-$(CONFIG_9P_FS_POSIX_ACL) += acl.o
diff --git a/fs/9p/acl.c b/fs/9p/acl.c
new file mode 100644
index 000000000..4dac4a0dc
--- /dev/null
+++ b/fs/9p/acl.c
@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/posix_acl_xattr.h>
+#include "xattr.h"
+#include "acl.h"
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
+{
+	ssize_t size;
+	void *value = NULL;
+	struct posix_acl *acl = NULL;
+
+	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
+	if (size > 0) {
+		value = kzalloc(size, GFP_NOFS);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		size = v9fs_fid_xattr_get(fid, name, value, size);
+		if (size > 0) {
+			acl = posix_acl_from_xattr(&init_user_ns, value, size);
+			if (IS_ERR(acl))
+				goto err_out;
+		}
+	} else if (size == -ENODATA || size == 0 ||
+		   size == -ENOSYS || size == -EOPNOTSUPP) {
+		acl = NULL;
+	} else
+		acl = ERR_PTR(-EIO);
+
+err_out:
+	kfree(value);
+	return acl;
+}
+
+int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
+{
+	int retval = 0;
+	struct posix_acl *pacl, *dacl;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
+			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
+		set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
+		set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
+		return 0;
+	}
+	/* get the default/access acl values and cache them */
+	dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
+	pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
+
+	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
+		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
+		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
+	} else
+		retval = -EIO;
+
+	if (!IS_ERR(dacl))
+		posix_acl_release(dacl);
+
+	if (!IS_ERR(pacl))
+		posix_acl_release(pacl);
+
+	return retval;
+}
+
+static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
+{
+	struct posix_acl *acl;
+	/*
+	 * 9p Always cache the acl value when
+	 * instantiating the inode (v9fs_inode_from_fid)
+	 */
+	acl = get_cached_acl(inode, type);
+	BUG_ON(is_uncached_acl(acl));
+	return acl;
+}
+
+struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, bool rcu)
+{
+	struct v9fs_session_info *v9ses;
+
+	if (rcu)
+		return ERR_PTR(-ECHILD);
+
+	v9ses = v9fs_inode2v9ses(inode);
+	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
+			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
+		/*
+		 * On access = client  and acl = on mode get the acl
+		 * values from the server
+		 */
+		return NULL;
+	}
+	return v9fs_get_cached_acl(inode, type);
+
+}
+
+static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
+{
+	int retval;
+	char *name;
+	size_t size;
+	void *buffer;
+
+	if (!acl)
+		return 0;
+
+	/* Set a setxattr request to server */
+	size = posix_acl_xattr_size(acl->a_count);
+	buffer = kmalloc(size, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+	retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+	if (retval < 0)
+		goto err_free_out;
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
+err_free_out:
+	kfree(buffer);
+	return retval;
+}
+
+int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
+{
+	int retval = 0;
+	struct posix_acl *acl;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
+	if (acl) {
+		retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+		if (retval)
+			return retval;
+		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
+		retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
+		posix_acl_release(acl);
+	}
+	return retval;
+}
+
+int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
+			struct posix_acl *dacl, struct posix_acl *acl)
+{
+	set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
+	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
+	v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
+	v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
+	return 0;
+}
+
+void v9fs_put_acl(struct posix_acl *dacl,
+		  struct posix_acl *acl)
+{
+	posix_acl_release(dacl);
+	posix_acl_release(acl);
+}
+
+int v9fs_acl_mode(struct inode *dir, umode_t *modep,
+		  struct posix_acl **dpacl, struct posix_acl **pacl)
+{
+	int retval = 0;
+	umode_t mode = *modep;
+	struct posix_acl *acl = NULL;
+
+	if (!S_ISLNK(mode)) {
+		acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		if (!acl)
+			mode &= ~current_umask();
+	}
+	if (acl) {
+		if (S_ISDIR(mode))
+			*dpacl = posix_acl_dup(acl);
+		retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
+		if (retval < 0)
+			return retval;
+		if (retval > 0)
+			*pacl = acl;
+		else
+			posix_acl_release(acl);
+	}
+	*modep  = mode;
+	return 0;
+}
+
+static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
+			      struct dentry *dentry, struct inode *inode,
+			      const char *name, void *buffer, size_t size)
+{
+	struct v9fs_session_info *v9ses;
+	struct posix_acl *acl;
+	int error;
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	/*
+	 * We allow set/get/list of acl when access=client is not specified
+	 */
+	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
+		return v9fs_xattr_get(dentry, handler->name, buffer, size);
+
+	acl = v9fs_get_cached_acl(inode, handler->flags);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl == NULL)
+		return -ENODATA;
+	error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+	posix_acl_release(acl);
+
+	return error;
+}
+
+static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
+			      struct user_namespace *mnt_userns,
+			      struct dentry *dentry, struct inode *inode,
+			      const char *name, const void *value,
+			      size_t size, int flags)
+{
+	int retval;
+	struct posix_acl *acl;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	/*
+	 * set the attribute on the remote. Without even looking at the
+	 * xattr value. We leave it to the server to validate
+	 */
+	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
+		return v9fs_xattr_set(dentry, handler->name, value, size,
+				      flags);
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	if (!inode_owner_or_capable(&init_user_ns, inode))
+		return -EPERM;
+	if (value) {
+		/* update the cached acl value */
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		else if (acl) {
+			retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
+			if (retval)
+				goto err_out;
+		}
+	} else
+		acl = NULL;
+
+	switch (handler->flags) {
+	case ACL_TYPE_ACCESS:
+		if (acl) {
+			struct iattr iattr = { 0 };
+			struct posix_acl *old_acl = acl;
+
+			retval = posix_acl_update_mode(&init_user_ns, inode,
+						       &iattr.ia_mode, &acl);
+			if (retval)
+				goto err_out;
+			if (!acl) {
+				/*
+				 * ACL can be represented
+				 * by the mode bits. So don't
+				 * update ACL.
+				 */
+				posix_acl_release(old_acl);
+				value = NULL;
+				size = 0;
+			}
+			iattr.ia_valid = ATTR_MODE;
+			/* FIXME should we update ctime ?
+			 * What is the following setxattr update the
+			 * mode ?
+			 */
+			v9fs_vfs_setattr_dotl(&init_user_ns, dentry, &iattr);
+		}
+		break;
+	case ACL_TYPE_DEFAULT:
+		if (!S_ISDIR(inode->i_mode)) {
+			retval = acl ? -EINVAL : 0;
+			goto err_out;
+		}
+		break;
+	default:
+		BUG();
+	}
+	retval = v9fs_xattr_set(dentry, handler->name, value, size, flags);
+	if (!retval)
+		set_cached_acl(inode, handler->flags, acl);
+err_out:
+	posix_acl_release(acl);
+	return retval;
+}
+
+const struct xattr_handler v9fs_xattr_acl_access_handler = {
+	.name	= XATTR_NAME_POSIX_ACL_ACCESS,
+	.flags	= ACL_TYPE_ACCESS,
+	.get	= v9fs_xattr_get_acl,
+	.set	= v9fs_xattr_set_acl,
+};
+
+const struct xattr_handler v9fs_xattr_acl_default_handler = {
+	.name	= XATTR_NAME_POSIX_ACL_DEFAULT,
+	.flags	= ACL_TYPE_DEFAULT,
+	.get	= v9fs_xattr_get_acl,
+	.set	= v9fs_xattr_set_acl,
+};
diff --git a/fs/9p/acl.h b/fs/9p/acl.h
new file mode 100644
index 000000000..ce5175d46
--- /dev/null
+++ b/fs/9p/acl.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: LGPL-2.1 */
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ */
+#ifndef FS_9P_ACL_H
+#define FS_9P_ACL_H
+
+#ifdef CONFIG_9P_FS_POSIX_ACL
+int v9fs_get_acl(struct inode *inode, struct p9_fid *fid);
+struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type,
+				   bool rcu);
+int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid);
+int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
+			struct posix_acl *dacl, struct posix_acl *acl);
+int v9fs_acl_mode(struct inode *dir, umode_t *modep,
+		  struct posix_acl **dpacl, struct posix_acl **pacl);
+void v9fs_put_acl(struct posix_acl *dacl, struct posix_acl *acl);
+#else
+#define v9fs_iop_get_acl NULL
+static inline int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
+{
+	return 0;
+}
+static inline int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
+{
+	return 0;
+}
+static inline int v9fs_set_create_acl(struct inode *inode,
+				      struct p9_fid *fid,
+				      struct posix_acl *dacl,
+				      struct posix_acl *acl)
+{
+	return 0;
+}
+static inline void v9fs_put_acl(struct posix_acl *dacl,
+				struct posix_acl *acl)
+{
+}
+static inline int v9fs_acl_mode(struct inode *dir, umode_t *modep,
+				struct posix_acl **dpacl,
+				struct posix_acl **pacl)
+{
+	return 0;
+}
+
+#endif
+#endif /* FS_9P_XATTR_H */
diff --git a/fs/9p/cache.c b/fs/9p/cache.c
new file mode 100644
index 000000000..12c0ae29f
--- /dev/null
+++ b/fs/9p/cache.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * V9FS cache definitions.
+ *
+ *  Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
+ */
+
+#include <linux/jiffies.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <net/9p/9p.h>
+
+#include "v9fs.h"
+#include "cache.h"
+
+int v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses,
+				  const char *dev_name)
+{
+	struct fscache_volume *vcookie;
+	char *name, *p;
+
+	name = kasprintf(GFP_KERNEL, "9p,%s,%s",
+			 dev_name, v9ses->cachetag ?: v9ses->aname);
+	if (!name)
+		return -ENOMEM;
+
+	for (p = name; *p; p++)
+		if (*p == '/')
+			*p = ';';
+
+	vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
+	p9_debug(P9_DEBUG_FSC, "session %p get volume %p (%s)\n",
+		 v9ses, vcookie, name);
+	if (IS_ERR(vcookie)) {
+		if (vcookie != ERR_PTR(-EBUSY)) {
+			kfree(name);
+			return PTR_ERR(vcookie);
+		}
+		pr_err("Cache volume key already in use (%s)\n", name);
+		vcookie = NULL;
+	}
+	v9ses->fscache = vcookie;
+	kfree(name);
+	return 0;
+}
+
+void v9fs_cache_inode_get_cookie(struct inode *inode)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct v9fs_session_info *v9ses;
+	__le32 version;
+	__le64 path;
+
+	if (!S_ISREG(inode->i_mode))
+		return;
+	if (WARN_ON(v9fs_inode_cookie(v9inode)))
+		return;
+
+	version = cpu_to_le32(v9inode->qid.version);
+	path = cpu_to_le64(v9inode->qid.path);
+	v9ses = v9fs_inode2v9ses(inode);
+	v9inode->netfs.cache =
+		fscache_acquire_cookie(v9fs_session_cache(v9ses),
+				       0,
+				       &path, sizeof(path),
+				       &version, sizeof(version),
+				       i_size_read(&v9inode->netfs.inode));
+	if (v9inode->netfs.cache)
+		mapping_set_release_always(inode->i_mapping);
+
+	p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
+		 inode, v9fs_inode_cookie(v9inode));
+}
diff --git a/fs/9p/cache.h b/fs/9p/cache.h
new file mode 100644
index 000000000..1923affcd
--- /dev/null
+++ b/fs/9p/cache.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * V9FS cache definitions.
+ *
+ *  Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
+ */
+
+#ifndef _9P_CACHE_H
+#define _9P_CACHE_H
+
+#include <linux/fscache.h>
+
+#ifdef CONFIG_9P_FSCACHE
+
+extern int v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses,
+					  const char *dev_name);
+
+extern void v9fs_cache_inode_get_cookie(struct inode *inode);
+
+#else /* CONFIG_9P_FSCACHE */
+
+static inline void v9fs_cache_inode_get_cookie(struct inode *inode)
+{
+}
+
+#endif /* CONFIG_9P_FSCACHE */
+#endif /* _9P_CACHE_H */
diff --git a/fs/9p/fid.c b/fs/9p/fid.c
new file mode 100644
index 000000000..23cf9b2fb
--- /dev/null
+++ b/fs/9p/fid.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * V9FS FID Management
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ *  Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/idr.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
+{
+	hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
+}
+
+
+/**
+ * v9fs_fid_add - add a fid to a dentry
+ * @dentry: dentry that the fid is being added to
+ * @pfid: fid to add, NULLed out
+ *
+ */
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid **pfid)
+{
+	struct p9_fid *fid = *pfid;
+
+	spin_lock(&dentry->d_lock);
+	__add_fid(dentry, fid);
+	spin_unlock(&dentry->d_lock);
+
+	*pfid = NULL;
+}
+
+/**
+ * v9fs_fid_find_inode - search for an open fid off of the inode list
+ * @inode: return a fid pointing to a specific inode
+ * @uid: return a fid belonging to the specified user
+ *
+ */
+
+static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
+{
+	struct hlist_head *h;
+	struct p9_fid *fid, *ret = NULL;
+
+	p9_debug(P9_DEBUG_VFS, " inode: %p\n", inode);
+
+	spin_lock(&inode->i_lock);
+	h = (struct hlist_head *)&inode->i_private;
+	hlist_for_each_entry(fid, h, ilist) {
+		if (uid_eq(fid->uid, uid)) {
+			p9_fid_get(fid);
+			ret = fid;
+			break;
+		}
+	}
+	spin_unlock(&inode->i_lock);
+	return ret;
+}
+
+/**
+ * v9fs_open_fid_add - add an open fid to an inode
+ * @inode: inode that the fid is being added to
+ * @pfid: fid to add, NULLed out
+ *
+ */
+
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid **pfid)
+{
+	struct p9_fid *fid = *pfid;
+
+	spin_lock(&inode->i_lock);
+	hlist_add_head(&fid->ilist, (struct hlist_head *)&inode->i_private);
+	spin_unlock(&inode->i_lock);
+
+	*pfid = NULL;
+}
+
+
+/**
+ * v9fs_fid_find - retrieve a fid that belongs to the specified uid
+ * @dentry: dentry to look for fid in
+ * @uid: return fid that belongs to the specified user
+ * @any: if non-zero, return any fid associated with the dentry
+ *
+ */
+
+static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
+{
+	struct p9_fid *fid, *ret;
+
+	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n",
+		 dentry, dentry, from_kuid(&init_user_ns, uid),
+		 any);
+	ret = NULL;
+	/* we'll recheck under lock if there's anything to look in */
+	if (dentry->d_fsdata) {
+		struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
+
+		spin_lock(&dentry->d_lock);
+		hlist_for_each_entry(fid, h, dlist) {
+			if (any || uid_eq(fid->uid, uid)) {
+				ret = fid;
+				p9_fid_get(ret);
+				break;
+			}
+		}
+		spin_unlock(&dentry->d_lock);
+	} else {
+		if (dentry->d_inode)
+			ret = v9fs_fid_find_inode(dentry->d_inode, uid);
+	}
+
+	return ret;
+}
+
+/*
+ * We need to hold v9ses->rename_sem as long as we hold references
+ * to returned path array. Array element contain pointers to
+ * dentry names.
+ */
+static int build_path_from_dentry(struct v9fs_session_info *v9ses,
+				  struct dentry *dentry, const unsigned char ***names)
+{
+	int n = 0, i;
+	const unsigned char **wnames;
+	struct dentry *ds;
+
+	for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
+		n++;
+
+	wnames = kmalloc_array(n, sizeof(char *), GFP_KERNEL);
+	if (!wnames)
+		goto err_out;
+
+	for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent)
+		wnames[i] = ds->d_name.name;
+
+	*names = wnames;
+	return n;
+err_out:
+	return -ENOMEM;
+}
+
+static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
+					       kuid_t uid, int any)
+{
+	struct dentry *ds;
+	const unsigned char **wnames, *uname;
+	int i, n, l, access;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid, *root_fid, *old_fid;
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	access = v9ses->flags & V9FS_ACCESS_MASK;
+	fid = v9fs_fid_find(dentry, uid, any);
+	if (fid)
+		return fid;
+	/*
+	 * we don't have a matching fid. To do a TWALK we need
+	 * parent fid. We need to prevent rename when we want to
+	 * look at the parent.
+	 */
+	down_read(&v9ses->rename_sem);
+	ds = dentry->d_parent;
+	fid = v9fs_fid_find(ds, uid, any);
+	if (fid) {
+		/* Found the parent fid do a lookup with that */
+		old_fid = fid;
+
+		fid = p9_client_walk(old_fid, 1, &dentry->d_name.name, 1);
+		p9_fid_put(old_fid);
+		goto fid_out;
+	}
+	up_read(&v9ses->rename_sem);
+
+	/* start from the root and try to do a lookup */
+	root_fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
+	if (!root_fid) {
+		/* the user is not attached to the fs yet */
+		if (access == V9FS_ACCESS_SINGLE)
+			return ERR_PTR(-EPERM);
+
+		if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
+			uname = NULL;
+		else
+			uname = v9ses->uname;
+
+		fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+				       v9ses->aname);
+		if (IS_ERR(fid))
+			return fid;
+
+		root_fid = p9_fid_get(fid);
+		v9fs_fid_add(dentry->d_sb->s_root, &fid);
+	}
+	/* If we are root ourself just return that */
+	if (dentry->d_sb->s_root == dentry)
+		return root_fid;
+
+	/*
+	 * Do a multipath walk with attached root.
+	 * When walking parent we need to make sure we
+	 * don't have a parallel rename happening
+	 */
+	down_read(&v9ses->rename_sem);
+	n  = build_path_from_dentry(v9ses, dentry, &wnames);
+	if (n < 0) {
+		fid = ERR_PTR(n);
+		goto err_out;
+	}
+	fid = root_fid;
+	old_fid = root_fid;
+	i = 0;
+	while (i < n) {
+		l = min(n - i, P9_MAXWELEM);
+		/*
+		 * We need to hold rename lock when doing a multipath
+		 * walk to ensure none of the path components change
+		 */
+		fid = p9_client_walk(old_fid, l, &wnames[i],
+				     old_fid == root_fid /* clone */);
+		/* non-cloning walk will return the same fid */
+		if (fid != old_fid) {
+			p9_fid_put(old_fid);
+			old_fid = fid;
+		}
+		if (IS_ERR(fid)) {
+			kfree(wnames);
+			goto err_out;
+		}
+		i += l;
+	}
+	kfree(wnames);
+fid_out:
+	if (!IS_ERR(fid)) {
+		spin_lock(&dentry->d_lock);
+		if (d_unhashed(dentry)) {
+			spin_unlock(&dentry->d_lock);
+			p9_fid_put(fid);
+			fid = ERR_PTR(-ENOENT);
+		} else {
+			__add_fid(dentry, fid);
+			p9_fid_get(fid);
+			spin_unlock(&dentry->d_lock);
+		}
+	}
+err_out:
+	up_read(&v9ses->rename_sem);
+	return fid;
+}
+
+/**
+ * v9fs_fid_lookup - lookup for a fid, try to walk if not found
+ * @dentry: dentry to look for fid in
+ *
+ * Look for a fid in the specified dentry for the current user.
+ * If no fid is found, try to create one walking from a fid from the parent
+ * dentry (if it has one), or the root dentry. If the user haven't accessed
+ * the fs yet, attach now and walk from the root.
+ */
+
+struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
+{
+	kuid_t uid;
+	int  any, access;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	access = v9ses->flags & V9FS_ACCESS_MASK;
+	switch (access) {
+	case V9FS_ACCESS_SINGLE:
+	case V9FS_ACCESS_USER:
+	case V9FS_ACCESS_CLIENT:
+		uid = current_fsuid();
+		any = 0;
+		break;
+
+	case V9FS_ACCESS_ANY:
+		uid = v9ses->uid;
+		any = 1;
+		break;
+
+	default:
+		uid = INVALID_UID;
+		any = 0;
+		break;
+	}
+	return v9fs_fid_lookup_with_uid(dentry, uid, any);
+}
+
+struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
+{
+	int err;
+	struct p9_fid *fid, *ofid;
+
+	ofid = v9fs_fid_lookup_with_uid(dentry, GLOBAL_ROOT_UID, 0);
+	fid = clone_fid(ofid);
+	if (IS_ERR(fid))
+		goto error_out;
+	p9_fid_put(ofid);
+	/*
+	 * writeback fid will only be used to write back the
+	 * dirty pages. We always request for the open fid in read-write
+	 * mode so that a partial page write which result in page
+	 * read can work.
+	 */
+	err = p9_client_open(fid, O_RDWR);
+	if (err < 0) {
+		p9_fid_put(fid);
+		fid = ERR_PTR(err);
+		goto error_out;
+	}
+error_out:
+	return fid;
+}
diff --git a/fs/9p/fid.h b/fs/9p/fid.h
new file mode 100644
index 000000000..8a4e8cd12
--- /dev/null
+++ b/fs/9p/fid.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * V9FS FID Management
+ *
+ *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
+ */
+#ifndef FS_9P_FID_H
+#define FS_9P_FID_H
+#include <linux/list.h>
+
+struct p9_fid *v9fs_fid_lookup(struct dentry *dentry);
+static inline struct p9_fid *v9fs_parent_fid(struct dentry *dentry)
+{
+	return v9fs_fid_lookup(dentry->d_parent);
+}
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid **fid);
+struct p9_fid *v9fs_writeback_fid(struct dentry *dentry);
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid **fid);
+static inline struct p9_fid *clone_fid(struct p9_fid *fid)
+{
+	return IS_ERR(fid) ? fid :  p9_client_walk(fid, 0, NULL, 1);
+}
+static inline struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
+{
+	struct p9_fid *fid, *nfid;
+
+	fid = v9fs_fid_lookup(dentry);
+	if (!fid || IS_ERR(fid))
+		return fid;
+
+	nfid = clone_fid(fid);
+	p9_fid_put(fid);
+	return nfid;
+}
+#endif
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
new file mode 100644
index 000000000..0129de2ea
--- /dev/null
+++ b/fs/9p/v9fs.c
@@ -0,0 +1,735 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  This file contains functions assisting in mapping VFS to 9P2000
+ *
+ *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/parser.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <net/9p/transport.h>
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "cache.h"
+
+static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
+static LIST_HEAD(v9fs_sessionlist);
+struct kmem_cache *v9fs_inode_cache;
+
+/*
+ * Option Parsing (code inspired by NFS code)
+ *  NOTE: each transport will parse its own options
+ */
+
+enum {
+	/* Options that take integer arguments */
+	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
+	/* String options */
+	Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
+	/* Options that take no arguments */
+	Opt_nodevmap,
+	/* Cache options */
+	Opt_cache_loose, Opt_fscache, Opt_mmap,
+	/* Access options */
+	Opt_access, Opt_posixacl,
+	/* Lock timeout option */
+	Opt_locktimeout,
+	/* Error token */
+	Opt_err
+};
+
+static const match_table_t tokens = {
+	{Opt_debug, "debug=%x"},
+	{Opt_dfltuid, "dfltuid=%u"},
+	{Opt_dfltgid, "dfltgid=%u"},
+	{Opt_afid, "afid=%u"},
+	{Opt_uname, "uname=%s"},
+	{Opt_remotename, "aname=%s"},
+	{Opt_nodevmap, "nodevmap"},
+	{Opt_cache, "cache=%s"},
+	{Opt_cache_loose, "loose"},
+	{Opt_fscache, "fscache"},
+	{Opt_mmap, "mmap"},
+	{Opt_cachetag, "cachetag=%s"},
+	{Opt_access, "access=%s"},
+	{Opt_posixacl, "posixacl"},
+	{Opt_locktimeout, "locktimeout=%u"},
+	{Opt_err, NULL}
+};
+
+static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
+	[CACHE_NONE]	= "none",
+	[CACHE_MMAP]	= "mmap",
+	[CACHE_LOOSE]	= "loose",
+	[CACHE_FSCACHE]	= "fscache",
+};
+
+/* Interpret mount options for cache mode */
+static int get_cache_mode(char *s)
+{
+	int version = -EINVAL;
+
+	if (!strcmp(s, "loose")) {
+		version = CACHE_LOOSE;
+		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
+	} else if (!strcmp(s, "fscache")) {
+		version = CACHE_FSCACHE;
+		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
+	} else if (!strcmp(s, "mmap")) {
+		version = CACHE_MMAP;
+		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
+	} else if (!strcmp(s, "none")) {
+		version = CACHE_NONE;
+		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
+	} else
+		pr_info("Unknown Cache mode %s\n", s);
+	return version;
+}
+
+/*
+ * Display the mount options in /proc/mounts.
+ */
+int v9fs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
+
+	if (v9ses->debug)
+		seq_printf(m, ",debug=%x", v9ses->debug);
+	if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
+		seq_printf(m, ",dfltuid=%u",
+			   from_kuid_munged(&init_user_ns, v9ses->dfltuid));
+	if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
+		seq_printf(m, ",dfltgid=%u",
+			   from_kgid_munged(&init_user_ns, v9ses->dfltgid));
+	if (v9ses->afid != ~0)
+		seq_printf(m, ",afid=%u", v9ses->afid);
+	if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
+		seq_printf(m, ",uname=%s", v9ses->uname);
+	if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
+		seq_printf(m, ",aname=%s", v9ses->aname);
+	if (v9ses->nodev)
+		seq_puts(m, ",nodevmap");
+	if (v9ses->cache)
+		seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
+#ifdef CONFIG_9P_FSCACHE
+	if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
+		seq_printf(m, ",cachetag=%s", v9ses->cachetag);
+#endif
+
+	switch (v9ses->flags & V9FS_ACCESS_MASK) {
+	case V9FS_ACCESS_USER:
+		seq_puts(m, ",access=user");
+		break;
+	case V9FS_ACCESS_ANY:
+		seq_puts(m, ",access=any");
+		break;
+	case V9FS_ACCESS_CLIENT:
+		seq_puts(m, ",access=client");
+		break;
+	case V9FS_ACCESS_SINGLE:
+		seq_printf(m, ",access=%u",
+			   from_kuid_munged(&init_user_ns, v9ses->uid));
+		break;
+	}
+
+	if (v9ses->flags & V9FS_POSIX_ACL)
+		seq_puts(m, ",posixacl");
+
+	return p9_show_client_options(m, v9ses->clnt);
+}
+
+/**
+ * v9fs_parse_options - parse mount options into session structure
+ * @v9ses: existing v9fs session information
+ * @opts: The mount option string
+ *
+ * Return 0 upon success, -ERRNO upon failure.
+ */
+
+static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
+{
+	char *options, *tmp_options;
+	substring_t args[MAX_OPT_ARGS];
+	char *p;
+	int option = 0;
+	char *s;
+	int ret = 0;
+
+	/* setup defaults */
+	v9ses->afid = ~0;
+	v9ses->debug = 0;
+	v9ses->cache = CACHE_NONE;
+#ifdef CONFIG_9P_FSCACHE
+	v9ses->cachetag = NULL;
+#endif
+	v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
+
+	if (!opts)
+		return 0;
+
+	tmp_options = kstrdup(opts, GFP_KERNEL);
+	if (!tmp_options) {
+		ret = -ENOMEM;
+		goto fail_option_alloc;
+	}
+	options = tmp_options;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token, r;
+
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_debug:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "integer field, but no integer?\n");
+				ret = r;
+			} else {
+				v9ses->debug = option;
+#ifdef CONFIG_NET_9P_DEBUG
+				p9_debug_level = option;
+#endif
+			}
+			break;
+
+		case Opt_dfltuid:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
+			v9ses->dfltuid = make_kuid(current_user_ns(), option);
+			if (!uid_valid(v9ses->dfltuid)) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "uid field, but not a uid?\n");
+				ret = -EINVAL;
+			}
+			break;
+		case Opt_dfltgid:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
+			v9ses->dfltgid = make_kgid(current_user_ns(), option);
+			if (!gid_valid(v9ses->dfltgid)) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "gid field, but not a gid?\n");
+				ret = -EINVAL;
+			}
+			break;
+		case Opt_afid:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "integer field, but no integer?\n");
+				ret = r;
+			} else {
+				v9ses->afid = option;
+			}
+			break;
+		case Opt_uname:
+			kfree(v9ses->uname);
+			v9ses->uname = match_strdup(&args[0]);
+			if (!v9ses->uname) {
+				ret = -ENOMEM;
+				goto free_and_return;
+			}
+			break;
+		case Opt_remotename:
+			kfree(v9ses->aname);
+			v9ses->aname = match_strdup(&args[0]);
+			if (!v9ses->aname) {
+				ret = -ENOMEM;
+				goto free_and_return;
+			}
+			break;
+		case Opt_nodevmap:
+			v9ses->nodev = 1;
+			break;
+		case Opt_cache_loose:
+			v9ses->cache = CACHE_LOOSE;
+			break;
+		case Opt_fscache:
+			v9ses->cache = CACHE_FSCACHE;
+			break;
+		case Opt_mmap:
+			v9ses->cache = CACHE_MMAP;
+			break;
+		case Opt_cachetag:
+#ifdef CONFIG_9P_FSCACHE
+			kfree(v9ses->cachetag);
+			v9ses->cachetag = match_strdup(&args[0]);
+			if (!v9ses->cachetag) {
+				ret = -ENOMEM;
+				goto free_and_return;
+			}
+#endif
+			break;
+		case Opt_cache:
+			s = match_strdup(&args[0]);
+			if (!s) {
+				ret = -ENOMEM;
+				p9_debug(P9_DEBUG_ERROR,
+					 "problem allocating copy of cache arg\n");
+				goto free_and_return;
+			}
+			r = get_cache_mode(s);
+			if (r < 0)
+				ret = r;
+			else
+				v9ses->cache = r;
+
+			kfree(s);
+			break;
+
+		case Opt_access:
+			s = match_strdup(&args[0]);
+			if (!s) {
+				ret = -ENOMEM;
+				p9_debug(P9_DEBUG_ERROR,
+					 "problem allocating copy of access arg\n");
+				goto free_and_return;
+			}
+
+			v9ses->flags &= ~V9FS_ACCESS_MASK;
+			if (strcmp(s, "user") == 0)
+				v9ses->flags |= V9FS_ACCESS_USER;
+			else if (strcmp(s, "any") == 0)
+				v9ses->flags |= V9FS_ACCESS_ANY;
+			else if (strcmp(s, "client") == 0) {
+				v9ses->flags |= V9FS_ACCESS_CLIENT;
+			} else {
+				uid_t uid;
+
+				v9ses->flags |= V9FS_ACCESS_SINGLE;
+				r = kstrtouint(s, 10, &uid);
+				if (r) {
+					ret = r;
+					pr_info("Unknown access argument %s: %d\n",
+						s, r);
+					kfree(s);
+					continue;
+				}
+				v9ses->uid = make_kuid(current_user_ns(), uid);
+				if (!uid_valid(v9ses->uid)) {
+					ret = -EINVAL;
+					pr_info("Unknown uid %s\n", s);
+				}
+			}
+
+			kfree(s);
+			break;
+
+		case Opt_posixacl:
+#ifdef CONFIG_9P_FS_POSIX_ACL
+			v9ses->flags |= V9FS_POSIX_ACL;
+#else
+			p9_debug(P9_DEBUG_ERROR,
+				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
+#endif
+			break;
+
+		case Opt_locktimeout:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
+			if (option < 1) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "locktimeout must be a greater than zero integer.\n");
+				ret = -EINVAL;
+				continue;
+			}
+			v9ses->session_lock_timeout = (long)option * HZ;
+			break;
+
+		default:
+			continue;
+		}
+	}
+
+free_and_return:
+	kfree(tmp_options);
+fail_option_alloc:
+	return ret;
+}
+
+/**
+ * v9fs_session_init - initialize session
+ * @v9ses: session information structure
+ * @dev_name: device being mounted
+ * @data: options
+ *
+ */
+
+struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
+		  const char *dev_name, char *data)
+{
+	struct p9_fid *fid;
+	int rc = -ENOMEM;
+
+	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
+	if (!v9ses->uname)
+		goto err_names;
+
+	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
+	if (!v9ses->aname)
+		goto err_names;
+	init_rwsem(&v9ses->rename_sem);
+
+	v9ses->uid = INVALID_UID;
+	v9ses->dfltuid = V9FS_DEFUID;
+	v9ses->dfltgid = V9FS_DEFGID;
+
+	v9ses->clnt = p9_client_create(dev_name, data);
+	if (IS_ERR(v9ses->clnt)) {
+		rc = PTR_ERR(v9ses->clnt);
+		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
+		goto err_names;
+	}
+
+	v9ses->flags = V9FS_ACCESS_USER;
+
+	if (p9_is_proto_dotl(v9ses->clnt)) {
+		v9ses->flags = V9FS_ACCESS_CLIENT;
+		v9ses->flags |= V9FS_PROTO_2000L;
+	} else if (p9_is_proto_dotu(v9ses->clnt)) {
+		v9ses->flags |= V9FS_PROTO_2000U;
+	}
+
+	rc = v9fs_parse_options(v9ses, data);
+	if (rc < 0)
+		goto err_clnt;
+
+	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
+
+	if (!v9fs_proto_dotl(v9ses) &&
+	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
+		/*
+		 * We support ACCESS_CLIENT only for dotl.
+		 * Fall back to ACCESS_USER
+		 */
+		v9ses->flags &= ~V9FS_ACCESS_MASK;
+		v9ses->flags |= V9FS_ACCESS_USER;
+	}
+	/*FIXME !! */
+	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
+	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
+		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
+
+		v9ses->flags &= ~V9FS_ACCESS_MASK;
+		v9ses->flags |= V9FS_ACCESS_ANY;
+		v9ses->uid = INVALID_UID;
+	}
+	if (!v9fs_proto_dotl(v9ses) ||
+		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
+		/*
+		 * We support ACL checks on clinet only if the protocol is
+		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
+		 */
+		v9ses->flags &= ~V9FS_ACL_MASK;
+	}
+
+	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
+							v9ses->aname);
+	if (IS_ERR(fid)) {
+		rc = PTR_ERR(fid);
+		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
+		goto err_clnt;
+	}
+
+	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
+		fid->uid = v9ses->uid;
+	else
+		fid->uid = INVALID_UID;
+
+#ifdef CONFIG_9P_FSCACHE
+	/* register the session for caching */
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		rc = v9fs_cache_session_get_cookie(v9ses, dev_name);
+		if (rc < 0)
+			goto err_clnt;
+	}
+#endif
+	spin_lock(&v9fs_sessionlist_lock);
+	list_add(&v9ses->slist, &v9fs_sessionlist);
+	spin_unlock(&v9fs_sessionlist_lock);
+
+	return fid;
+
+err_clnt:
+#ifdef CONFIG_9P_FSCACHE
+	kfree(v9ses->cachetag);
+#endif
+	p9_client_destroy(v9ses->clnt);
+err_names:
+	kfree(v9ses->uname);
+	kfree(v9ses->aname);
+	return ERR_PTR(rc);
+}
+
+/**
+ * v9fs_session_close - shutdown a session
+ * @v9ses: session information structure
+ *
+ */
+
+void v9fs_session_close(struct v9fs_session_info *v9ses)
+{
+	if (v9ses->clnt) {
+		p9_client_destroy(v9ses->clnt);
+		v9ses->clnt = NULL;
+	}
+
+#ifdef CONFIG_9P_FSCACHE
+	fscache_relinquish_volume(v9fs_session_cache(v9ses), NULL, false);
+	kfree(v9ses->cachetag);
+#endif
+	kfree(v9ses->uname);
+	kfree(v9ses->aname);
+
+	spin_lock(&v9fs_sessionlist_lock);
+	list_del(&v9ses->slist);
+	spin_unlock(&v9fs_sessionlist_lock);
+}
+
+/**
+ * v9fs_session_cancel - terminate a session
+ * @v9ses: session to terminate
+ *
+ * mark transport as disconnected and cancel all pending requests.
+ */
+
+void v9fs_session_cancel(struct v9fs_session_info *v9ses)
+{
+	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
+	p9_client_disconnect(v9ses->clnt);
+}
+
+/**
+ * v9fs_session_begin_cancel - Begin terminate of a session
+ * @v9ses: session to terminate
+ *
+ * After this call we don't allow any request other than clunk.
+ */
+
+void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
+{
+	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
+	p9_client_begin_disconnect(v9ses->clnt);
+}
+
+extern int v9fs_error_init(void);
+
+static struct kobject *v9fs_kobj;
+
+#ifdef CONFIG_9P_FSCACHE
+/*
+ * List caches associated with a session
+ */
+static ssize_t caches_show(struct kobject *kobj,
+			   struct kobj_attribute *attr,
+			   char *buf)
+{
+	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
+	struct v9fs_session_info *v9ses;
+
+	spin_lock(&v9fs_sessionlist_lock);
+	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
+		if (v9ses->cachetag) {
+			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
+			if (n < 0) {
+				count = n;
+				break;
+			}
+
+			count += n;
+			limit -= n;
+		}
+	}
+
+	spin_unlock(&v9fs_sessionlist_lock);
+	return count;
+}
+
+static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
+#endif /* CONFIG_9P_FSCACHE */
+
+static struct attribute *v9fs_attrs[] = {
+#ifdef CONFIG_9P_FSCACHE
+	&v9fs_attr_cache.attr,
+#endif
+	NULL,
+};
+
+static const struct attribute_group v9fs_attr_group = {
+	.attrs = v9fs_attrs,
+};
+
+/**
+ * v9fs_sysfs_init - Initialize the v9fs sysfs interface
+ *
+ */
+
+static int __init v9fs_sysfs_init(void)
+{
+	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
+	if (!v9fs_kobj)
+		return -ENOMEM;
+
+	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
+		kobject_put(v9fs_kobj);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
+ *
+ */
+
+static void v9fs_sysfs_cleanup(void)
+{
+	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
+	kobject_put(v9fs_kobj);
+}
+
+static void v9fs_inode_init_once(void *foo)
+{
+	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
+
+	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
+	inode_init_once(&v9inode->netfs.inode);
+}
+
+/**
+ * v9fs_init_inode_cache - initialize a cache for 9P
+ * Returns 0 on success.
+ */
+static int v9fs_init_inode_cache(void)
+{
+	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
+					  sizeof(struct v9fs_inode),
+					  0, (SLAB_RECLAIM_ACCOUNT|
+					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+					  v9fs_inode_init_once);
+	if (!v9fs_inode_cache)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * v9fs_destroy_inode_cache - destroy the cache of 9P inode
+ *
+ */
+static void v9fs_destroy_inode_cache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(v9fs_inode_cache);
+}
+
+static int v9fs_cache_register(void)
+{
+	int ret;
+
+	ret = v9fs_init_inode_cache();
+	if (ret < 0)
+		return ret;
+	return ret;
+}
+
+static void v9fs_cache_unregister(void)
+{
+	v9fs_destroy_inode_cache();
+}
+
+/**
+ * init_v9fs - Initialize module
+ *
+ */
+
+static int __init init_v9fs(void)
+{
+	int err;
+
+	pr_info("Installing v9fs 9p2000 file system support\n");
+	/* TODO: Setup list of registered trasnport modules */
+
+	err = v9fs_cache_register();
+	if (err < 0) {
+		pr_err("Failed to register v9fs for caching\n");
+		return err;
+	}
+
+	err = v9fs_sysfs_init();
+	if (err < 0) {
+		pr_err("Failed to register with sysfs\n");
+		goto out_cache;
+	}
+	err = register_filesystem(&v9fs_fs_type);
+	if (err < 0) {
+		pr_err("Failed to register filesystem\n");
+		goto out_sysfs_cleanup;
+	}
+
+	return 0;
+
+out_sysfs_cleanup:
+	v9fs_sysfs_cleanup();
+
+out_cache:
+	v9fs_cache_unregister();
+
+	return err;
+}
+
+/**
+ * exit_v9fs - shutdown module
+ *
+ */
+
+static void __exit exit_v9fs(void)
+{
+	v9fs_sysfs_cleanup();
+	v9fs_cache_unregister();
+	unregister_filesystem(&v9fs_fs_type);
+}
+
+module_init(init_v9fs)
+module_exit(exit_v9fs)
+
+MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
+MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
+MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
+MODULE_LICENSE("GPL");
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
new file mode 100644
index 000000000..6acabc2e7
--- /dev/null
+++ b/fs/9p/v9fs.h
@@ -0,0 +1,232 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * V9FS definitions.
+ *
+ *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+#ifndef FS_9P_V9FS_H
+#define FS_9P_V9FS_H
+
+#include <linux/backing-dev.h>
+#include <linux/netfs.h>
+
+/**
+ * enum p9_session_flags - option flags for each 9P session
+ * @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
+ * @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
+ * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
+ * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
+ * @V9FS_ACCESS_CLIENT: Just like user, but access check is performed on client.
+ * @V9FS_ACCESS_ANY: use a single attach for all users
+ * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
+ * @V9FS_POSIX_ACL: POSIX ACLs are enforced
+ *
+ * Session flags reflect options selected by users at mount time
+ */
+#define	V9FS_ACCESS_ANY (V9FS_ACCESS_SINGLE | \
+			 V9FS_ACCESS_USER |   \
+			 V9FS_ACCESS_CLIENT)
+#define V9FS_ACCESS_MASK V9FS_ACCESS_ANY
+#define V9FS_ACL_MASK V9FS_POSIX_ACL
+
+enum p9_session_flags {
+	V9FS_PROTO_2000U	= 0x01,
+	V9FS_PROTO_2000L	= 0x02,
+	V9FS_ACCESS_SINGLE	= 0x04,
+	V9FS_ACCESS_USER	= 0x08,
+	V9FS_ACCESS_CLIENT	= 0x10,
+	V9FS_POSIX_ACL		= 0x20
+};
+
+/* possible values of ->cache */
+/**
+ * enum p9_cache_modes - user specified cache preferences
+ * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
+ * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
+ *
+ * eventually support loose, tight, time, session, default always none
+ */
+
+enum p9_cache_modes {
+	CACHE_NONE,
+	CACHE_MMAP,
+	CACHE_LOOSE,
+	CACHE_FSCACHE,
+	nr__p9_cache_modes
+};
+
+/**
+ * struct v9fs_session_info - per-instance session information
+ * @flags: session options of type &p9_session_flags
+ * @nodev: set to 1 to disable device mapping
+ * @debug: debug level
+ * @afid: authentication handle
+ * @cache: cache mode of type &p9_cache_modes
+ * @cachetag: the tag of the cache associated with this session
+ * @fscache: session cookie associated with FS-Cache
+ * @uname: string user name to mount hierarchy as
+ * @aname: mount specifier for remote hierarchy
+ * @maxdata: maximum data to be sent/recvd per protocol message
+ * @dfltuid: default numeric userid to mount hierarchy as
+ * @dfltgid: default numeric groupid to mount hierarchy as
+ * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
+ * @clnt: reference to 9P network client instantiated for this session
+ * @slist: reference to list of registered 9p sessions
+ *
+ * This structure holds state for each session instance established during
+ * a sys_mount() .
+ *
+ * Bugs: there seems to be a lot of state which could be condensed and/or
+ * removed.
+ */
+
+struct v9fs_session_info {
+	/* options */
+	unsigned char flags;
+	unsigned char nodev;
+	unsigned short debug;
+	unsigned int afid;
+	unsigned int cache;
+#ifdef CONFIG_9P_FSCACHE
+	char *cachetag;
+	struct fscache_volume *fscache;
+#endif
+
+	char *uname;		/* user name to mount as */
+	char *aname;		/* name of remote hierarchy being mounted */
+	unsigned int maxdata;	/* max data for client interface */
+	kuid_t dfltuid;		/* default uid/muid for legacy support */
+	kgid_t dfltgid;		/* default gid for legacy support */
+	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
+	struct p9_client *clnt;	/* 9p client */
+	struct list_head slist; /* list of sessions registered with v9fs */
+	struct rw_semaphore rename_sem;
+	long session_lock_timeout; /* retry interval for blocking locks */
+};
+
+/* cache_validity flags */
+#define V9FS_INO_INVALID_ATTR 0x01
+
+struct v9fs_inode {
+	struct netfs_inode netfs; /* Netfslib context and vfs inode */
+	struct p9_qid qid;
+	unsigned int cache_validity;
+	struct p9_fid *writeback_fid;
+	struct mutex v_mutex;
+};
+
+static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
+{
+	return container_of(inode, struct v9fs_inode, netfs.inode);
+}
+
+static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
+{
+#ifdef CONFIG_9P_FSCACHE
+	return netfs_i_cookie(&v9inode->netfs);
+#else
+	return NULL;
+#endif
+}
+
+static inline struct fscache_volume *v9fs_session_cache(struct v9fs_session_info *v9ses)
+{
+#ifdef CONFIG_9P_FSCACHE
+	return v9ses->fscache;
+#else
+	return NULL;
+#endif
+}
+
+
+extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
+
+struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
+				 const char *dev_name, char *data);
+extern void v9fs_session_close(struct v9fs_session_info *v9ses);
+extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
+extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
+extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
+				      unsigned int flags);
+extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
+extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
+extern int v9fs_vfs_rename(struct user_namespace *mnt_userns,
+			   struct inode *old_dir, struct dentry *old_dentry,
+			   struct inode *new_dir, struct dentry *new_dentry,
+			   unsigned int flags);
+extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
+					 struct p9_fid *fid,
+					 struct super_block *sb, int new);
+extern const struct inode_operations v9fs_dir_inode_operations_dotl;
+extern const struct inode_operations v9fs_file_inode_operations_dotl;
+extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
+extern const struct netfs_request_ops v9fs_req_ops;
+extern struct inode *v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses,
+					      struct p9_fid *fid,
+					      struct super_block *sb, int new);
+
+/* other default globals */
+#define V9FS_PORT	564
+#define V9FS_DEFUSER	"nobody"
+#define V9FS_DEFANAME	""
+#define V9FS_DEFUID	KUIDT_INIT(-2)
+#define V9FS_DEFGID	KGIDT_INIT(-2)
+
+static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
+{
+	return inode->i_sb->s_fs_info;
+}
+
+static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
+{
+	return dentry->d_sb->s_fs_info;
+}
+
+static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
+{
+	return v9ses->flags & V9FS_PROTO_2000U;
+}
+
+static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
+{
+	return v9ses->flags & V9FS_PROTO_2000L;
+}
+
+/**
+ * v9fs_get_inode_from_fid - Helper routine to populate an inode by
+ * issuing a attribute request
+ * @v9ses: session information
+ * @fid: fid to issue attribute request for
+ * @sb: superblock on which to create inode
+ *
+ */
+static inline struct inode *
+v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
+			struct super_block *sb)
+{
+	if (v9fs_proto_dotl(v9ses))
+		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 0);
+	else
+		return v9fs_inode_from_fid(v9ses, fid, sb, 0);
+}
+
+/**
+ * v9fs_get_new_inode_from_fid - Helper routine to populate an inode by
+ * issuing a attribute request
+ * @v9ses: session information
+ * @fid: fid to issue attribute request for
+ * @sb: superblock on which to create inode
+ *
+ */
+static inline struct inode *
+v9fs_get_new_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
+			    struct super_block *sb)
+{
+	if (v9fs_proto_dotl(v9ses))
+		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 1);
+	else
+		return v9fs_inode_from_fid(v9ses, fid, sb, 1);
+}
+
+#endif
diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
new file mode 100644
index 000000000..bc417da7e
--- /dev/null
+++ b/fs/9p/v9fs_vfs.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * V9FS VFS extensions.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+#ifndef FS_9P_V9FS_VFS_H
+#define FS_9P_V9FS_VFS_H
+
+/* plan9 semantics are that created files are implicitly opened.
+ * But linux semantics are that you call create, then open.
+ * the plan9 approach is superior as it provides an atomic
+ * open.
+ * we track the create fid here. When the file is opened, if fidopen is
+ * non-zero, we use the fid and can skip some steps.
+ * there may be a better way to do this, but I don't know it.
+ * one BAD way is to clunk the fid on create, then open it again:
+ * you lose the atomicity of file open
+ */
+
+/* special case:
+ * unlink calls remove, which is an implicit clunk. So we have to track
+ * that kind of thing so that we don't try to clunk a dead fid.
+ */
+#define P9_LOCK_TIMEOUT (30*HZ)
+
+/* flags for v9fs_stat2inode() & v9fs_stat2inode_dotl() */
+#define V9FS_STAT2INODE_KEEP_ISIZE 1
+
+extern struct file_system_type v9fs_fs_type;
+extern const struct address_space_operations v9fs_addr_operations;
+extern const struct file_operations v9fs_file_operations;
+extern const struct file_operations v9fs_file_operations_dotl;
+extern const struct file_operations v9fs_dir_operations;
+extern const struct file_operations v9fs_dir_operations_dotl;
+extern const struct dentry_operations v9fs_dentry_operations;
+extern const struct dentry_operations v9fs_cached_dentry_operations;
+extern const struct file_operations v9fs_cached_file_operations;
+extern const struct file_operations v9fs_cached_file_operations_dotl;
+extern const struct file_operations v9fs_mmap_file_operations;
+extern const struct file_operations v9fs_mmap_file_operations_dotl;
+extern struct kmem_cache *v9fs_inode_cache;
+
+struct inode *v9fs_alloc_inode(struct super_block *sb);
+void v9fs_free_inode(struct inode *inode);
+struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode,
+			     dev_t rdev);
+int v9fs_init_inode(struct v9fs_session_info *v9ses,
+		    struct inode *inode, umode_t mode, dev_t rdev);
+void v9fs_evict_inode(struct inode *inode);
+ino_t v9fs_qid2ino(struct p9_qid *qid);
+void v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
+		      struct super_block *sb, unsigned int flags);
+void v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
+			   unsigned int flags);
+int v9fs_dir_release(struct inode *inode, struct file *filp);
+int v9fs_file_open(struct inode *inode, struct file *file);
+void v9fs_inode2stat(struct inode *inode, struct p9_wstat *stat);
+int v9fs_uflags2omode(int uflags, int extended);
+
+void v9fs_blank_wstat(struct p9_wstat *wstat);
+int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
+			  struct dentry *dentry, struct iattr *iattr);
+int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
+			 int datasync);
+int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode);
+int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode);
+static inline void v9fs_invalidate_inode_attr(struct inode *inode)
+{
+	struct v9fs_inode *v9inode;
+
+	v9inode = V9FS_I(inode);
+	v9inode->cache_validity |= V9FS_INO_INVALID_ATTR;
+}
+
+int v9fs_open_to_dotl_flags(int flags);
+
+static inline void v9fs_i_size_write(struct inode *inode, loff_t i_size)
+{
+	/*
+	 * 32-bit need the lock, concurrent updates could break the
+	 * sequences and make i_size_read() loop forever.
+	 * 64-bit updates are atomic and can skip the locking.
+	 */
+	if (sizeof(i_size) > sizeof(long))
+		spin_lock(&inode->i_lock);
+	i_size_write(inode, i_size);
+	if (sizeof(i_size) > sizeof(long))
+		spin_unlock(&inode->i_lock);
+}
+#endif
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
new file mode 100644
index 000000000..a19891015
--- /dev/null
+++ b/fs/9p/vfs_addr.c
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contians vfs address (mmap) ops for 9P2000.
+ *
+ *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/inet.h>
+#include <linux/pagemap.h>
+#include <linux/idr.h>
+#include <linux/sched.h>
+#include <linux/swap.h>
+#include <linux/uio.h>
+#include <linux/netfs.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "cache.h"
+#include "fid.h"
+
+/**
+ * v9fs_issue_read - Issue a read from 9P
+ * @subreq: The read to make
+ */
+static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
+{
+	struct netfs_io_request *rreq = subreq->rreq;
+	struct p9_fid *fid = rreq->netfs_priv;
+	struct iov_iter to;
+	loff_t pos = subreq->start + subreq->transferred;
+	size_t len = subreq->len   - subreq->transferred;
+	int total, err;
+
+	iov_iter_xarray(&to, ITER_DEST, &rreq->mapping->i_pages, pos, len);
+
+	total = p9_client_read(fid, pos, &to, &err);
+
+	/* if we just extended the file size, any portion not in
+	 * cache won't be on server and is zeroes */
+	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+
+	netfs_subreq_terminated(subreq, err ?: total, false);
+}
+
+/**
+ * v9fs_init_request - Initialise a read request
+ * @rreq: The read request
+ * @file: The file being read from
+ */
+static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
+{
+	struct inode *inode = file_inode(file);
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_fid *fid = file->private_data;
+
+	BUG_ON(!fid);
+
+	/* we might need to read from a fid that was opened write-only
+	 * for read-modify-write of page cache, use the writeback fid
+	 * for that */
+	if (rreq->origin == NETFS_READ_FOR_WRITE &&
+			(fid->mode & O_ACCMODE) == O_WRONLY) {
+		fid = v9inode->writeback_fid;
+		BUG_ON(!fid);
+	}
+
+	p9_fid_get(fid);
+	rreq->netfs_priv = fid;
+	return 0;
+}
+
+/**
+ * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq
+ * @rreq: The I/O request to clean up
+ */
+static void v9fs_free_request(struct netfs_io_request *rreq)
+{
+	struct p9_fid *fid = rreq->netfs_priv;
+
+	p9_fid_put(fid);
+}
+
+/**
+ * v9fs_begin_cache_operation - Begin a cache operation for a read
+ * @rreq: The read request
+ */
+static int v9fs_begin_cache_operation(struct netfs_io_request *rreq)
+{
+#ifdef CONFIG_9P_FSCACHE
+	struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode));
+
+	return fscache_begin_read_operation(&rreq->cache_resources, cookie);
+#else
+	return -ENOBUFS;
+#endif
+}
+
+const struct netfs_request_ops v9fs_req_ops = {
+	.init_request		= v9fs_init_request,
+	.free_request		= v9fs_free_request,
+	.begin_cache_operation	= v9fs_begin_cache_operation,
+	.issue_read		= v9fs_issue_read,
+};
+
+/**
+ * v9fs_release_folio - release the private state associated with a folio
+ * @folio: The folio to be released
+ * @gfp: The caller's allocation restrictions
+ *
+ * Returns true if the page can be released, false otherwise.
+ */
+
+static bool v9fs_release_folio(struct folio *folio, gfp_t gfp)
+{
+	struct inode *inode = folio_inode(folio);
+
+	if (folio_test_private(folio))
+		return false;
+#ifdef CONFIG_9P_FSCACHE
+	if (folio_test_fscache(folio)) {
+		if (current_is_kswapd() || !(gfp & __GFP_FS))
+			return false;
+		folio_wait_fscache(folio);
+	}
+#endif
+	fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode)));
+	return true;
+}
+
+static void v9fs_invalidate_folio(struct folio *folio, size_t offset,
+				 size_t length)
+{
+	folio_wait_fscache(folio);
+}
+
+static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error,
+				     bool was_async)
+{
+	struct v9fs_inode *v9inode = priv;
+	__le32 version;
+
+	if (IS_ERR_VALUE(transferred_or_error) &&
+	    transferred_or_error != -ENOBUFS) {
+		version = cpu_to_le32(v9inode->qid.version);
+		fscache_invalidate(v9fs_inode_cookie(v9inode), &version,
+				   i_size_read(&v9inode->netfs.inode), 0);
+	}
+}
+
+static int v9fs_vfs_write_folio_locked(struct folio *folio)
+{
+	struct inode *inode = folio_inode(folio);
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode);
+	loff_t start = folio_pos(folio);
+	loff_t i_size = i_size_read(inode);
+	struct iov_iter from;
+	size_t len = folio_size(folio);
+	int err;
+
+	if (start >= i_size)
+		return 0; /* Simultaneous truncation occurred */
+
+	len = min_t(loff_t, i_size - start, len);
+
+	iov_iter_xarray(&from, ITER_SOURCE, &folio_mapping(folio)->i_pages, start, len);
+
+	/* We should have writeback_fid always set */
+	BUG_ON(!v9inode->writeback_fid);
+
+	folio_wait_fscache(folio);
+	folio_start_writeback(folio);
+
+	p9_client_write(v9inode->writeback_fid, start, &from, &err);
+
+	if (err == 0 &&
+	    fscache_cookie_enabled(cookie) &&
+	    test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) {
+		folio_start_fscache(folio);
+		fscache_write_to_cache(v9fs_inode_cookie(v9inode),
+				       folio_mapping(folio), start, len, i_size,
+				       v9fs_write_to_cache_done, v9inode,
+				       true);
+	}
+
+	folio_end_writeback(folio);
+	return err;
+}
+
+static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct folio *folio = page_folio(page);
+	int retval;
+
+	p9_debug(P9_DEBUG_VFS, "folio %p\n", folio);
+
+	retval = v9fs_vfs_write_folio_locked(folio);
+	if (retval < 0) {
+		if (retval == -EAGAIN) {
+			folio_redirty_for_writepage(wbc, folio);
+			retval = 0;
+		} else {
+			mapping_set_error(folio_mapping(folio), retval);
+		}
+	} else
+		retval = 0;
+
+	folio_unlock(folio);
+	return retval;
+}
+
+static int v9fs_launder_folio(struct folio *folio)
+{
+	int retval;
+
+	if (folio_clear_dirty_for_io(folio)) {
+		retval = v9fs_vfs_write_folio_locked(folio);
+		if (retval)
+			return retval;
+	}
+	folio_wait_fscache(folio);
+	return 0;
+}
+
+/**
+ * v9fs_direct_IO - 9P address space operation for direct I/O
+ * @iocb: target I/O control block
+ * @iter: The data/buffer to use
+ *
+ * The presence of v9fs_direct_IO() in the address space ops vector
+ * allowes open() O_DIRECT flags which would have failed otherwise.
+ *
+ * In the non-cached mode, we shunt off direct read and write requests before
+ * the VFS gets them, so this method should never be called.
+ *
+ * Direct IO is not 'yet' supported in the cached mode. Hence when
+ * this routine is called through generic_file_aio_read(), the read/write fails
+ * with an error.
+ *
+ */
+static ssize_t
+v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	loff_t pos = iocb->ki_pos;
+	ssize_t n;
+	int err = 0;
+
+	if (iov_iter_rw(iter) == WRITE) {
+		n = p9_client_write(file->private_data, pos, iter, &err);
+		if (n) {
+			struct inode *inode = file_inode(file);
+			loff_t i_size = i_size_read(inode);
+
+			if (pos + n > i_size)
+				inode_add_bytes(inode, pos + n - i_size);
+		}
+	} else {
+		n = p9_client_read(file->private_data, pos, iter, &err);
+	}
+	return n ? n : err;
+}
+
+static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
+			    loff_t pos, unsigned int len,
+			    struct page **subpagep, void **fsdata)
+{
+	int retval;
+	struct folio *folio;
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
+
+	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
+
+	BUG_ON(!v9inode->writeback_fid);
+
+	/* Prefetch area to be written into the cache if we're caching this
+	 * file.  We need to do this before we get a lock on the page in case
+	 * there's more than one writer competing for the same cache block.
+	 */
+	retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata);
+	if (retval < 0)
+		return retval;
+
+	*subpagep = &folio->page;
+	return retval;
+}
+
+static int v9fs_write_end(struct file *filp, struct address_space *mapping,
+			  loff_t pos, unsigned int len, unsigned int copied,
+			  struct page *subpage, void *fsdata)
+{
+	loff_t last_pos = pos + copied;
+	struct folio *folio = page_folio(subpage);
+	struct inode *inode = mapping->host;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+
+	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
+
+	if (!folio_test_uptodate(folio)) {
+		if (unlikely(copied < len)) {
+			copied = 0;
+			goto out;
+		}
+
+		folio_mark_uptodate(folio);
+	}
+
+	/*
+	 * No need to use i_size_read() here, the i_size
+	 * cannot change under us because we hold the i_mutex.
+	 */
+	if (last_pos > inode->i_size) {
+		inode_add_bytes(inode, last_pos - inode->i_size);
+		i_size_write(inode, last_pos);
+		fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos);
+	}
+	folio_mark_dirty(folio);
+out:
+	folio_unlock(folio);
+	folio_put(folio);
+
+	return copied;
+}
+
+#ifdef CONFIG_9P_FSCACHE
+/*
+ * Mark a page as having been made dirty and thus needing writeback.  We also
+ * need to pin the cache object to write back to.
+ */
+static bool v9fs_dirty_folio(struct address_space *mapping, struct folio *folio)
+{
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
+
+	return fscache_dirty_folio(mapping, folio, v9fs_inode_cookie(v9inode));
+}
+#else
+#define v9fs_dirty_folio filemap_dirty_folio
+#endif
+
+const struct address_space_operations v9fs_addr_operations = {
+	.read_folio = netfs_read_folio,
+	.readahead = netfs_readahead,
+	.dirty_folio = v9fs_dirty_folio,
+	.writepage = v9fs_vfs_writepage,
+	.write_begin = v9fs_write_begin,
+	.write_end = v9fs_write_end,
+	.release_folio = v9fs_release_folio,
+	.invalidate_folio = v9fs_invalidate_folio,
+	.launder_folio = v9fs_launder_folio,
+	.direct_IO = v9fs_direct_IO,
+};
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
new file mode 100644
index 000000000..f89f01734
--- /dev/null
+++ b/fs/9p/vfs_dentry.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contians vfs dentry ops for the 9P2000 protocol.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/pagemap.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/inet.h>
+#include <linux/namei.h>
+#include <linux/idr.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+/**
+ * v9fs_cached_dentry_delete - called when dentry refcount equals 0
+ * @dentry:  dentry in question
+ *
+ */
+static int v9fs_cached_dentry_delete(const struct dentry *dentry)
+{
+	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
+		 dentry, dentry);
+
+	/* Don't cache negative dentries */
+	if (d_really_is_negative(dentry))
+		return 1;
+	return 0;
+}
+
+/**
+ * v9fs_dentry_release - called when dentry is going to be freed
+ * @dentry:  dentry that is being release
+ *
+ */
+
+static void v9fs_dentry_release(struct dentry *dentry)
+{
+	struct hlist_node *p, *n;
+
+	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
+		 dentry, dentry);
+	hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
+		p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
+	dentry->d_fsdata = NULL;
+}
+
+static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	struct p9_fid *fid;
+	struct inode *inode;
+	struct v9fs_inode *v9inode;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = d_inode(dentry);
+	if (!inode)
+		goto out_valid;
+
+	v9inode = V9FS_I(inode);
+	if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
+		int retval;
+		struct v9fs_session_info *v9ses;
+
+		fid = v9fs_fid_lookup(dentry);
+		if (IS_ERR(fid))
+			return PTR_ERR(fid);
+
+		v9ses = v9fs_inode2v9ses(inode);
+		if (v9fs_proto_dotl(v9ses))
+			retval = v9fs_refresh_inode_dotl(fid, inode);
+		else
+			retval = v9fs_refresh_inode(fid, inode);
+		p9_fid_put(fid);
+
+		if (retval == -ENOENT)
+			return 0;
+		if (retval < 0)
+			return retval;
+	}
+out_valid:
+	return 1;
+}
+
+const struct dentry_operations v9fs_cached_dentry_operations = {
+	.d_revalidate = v9fs_lookup_revalidate,
+	.d_weak_revalidate = v9fs_lookup_revalidate,
+	.d_delete = v9fs_cached_dentry_delete,
+	.d_release = v9fs_dentry_release,
+};
+
+const struct dentry_operations v9fs_dentry_operations = {
+	.d_delete = always_delete_dentry,
+	.d_release = v9fs_dentry_release,
+};
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
new file mode 100644
index 000000000..3bb95adc9
--- /dev/null
+++ b/fs/9p/vfs_dir.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contains vfs directory ops for the 9P2000 protocol.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/inet.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/fscache.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+/**
+ * struct p9_rdir - readdir accounting
+ * @head: start offset of current dirread buffer
+ * @tail: end offset of current dirread buffer
+ * @buf: dirread buffer
+ *
+ * private structure for keeping track of readdir
+ * allocated on demand
+ */
+
+struct p9_rdir {
+	int head;
+	int tail;
+	uint8_t buf[];
+};
+
+/**
+ * dt_type - return file type
+ * @mistat: mistat structure
+ *
+ */
+
+static inline int dt_type(struct p9_wstat *mistat)
+{
+	unsigned long perm = mistat->mode;
+	int rettype = DT_REG;
+
+	if (perm & P9_DMDIR)
+		rettype = DT_DIR;
+	if (perm & P9_DMSYMLINK)
+		rettype = DT_LNK;
+
+	return rettype;
+}
+
+/**
+ * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
+ * @filp: opened file structure
+ * @buflen: Length in bytes of buffer to allocate
+ *
+ */
+
+static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen)
+{
+	struct p9_fid *fid = filp->private_data;
+
+	if (!fid->rdir)
+		fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
+	return fid->rdir;
+}
+
+/**
+ * v9fs_dir_readdir - iterate through a directory
+ * @file: opened file structure
+ * @ctx: actor we feed the entries to
+ *
+ */
+
+static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
+{
+	bool over;
+	struct p9_wstat st;
+	int err = 0;
+	struct p9_fid *fid;
+	int buflen;
+	struct p9_rdir *rdir;
+	struct kvec kvec;
+
+	p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
+	fid = file->private_data;
+
+	buflen = fid->clnt->msize - P9_IOHDRSZ;
+
+	rdir = v9fs_alloc_rdir_buf(file, buflen);
+	if (!rdir)
+		return -ENOMEM;
+	kvec.iov_base = rdir->buf;
+	kvec.iov_len = buflen;
+
+	while (1) {
+		if (rdir->tail == rdir->head) {
+			struct iov_iter to;
+			int n;
+
+			iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buflen);
+			n = p9_client_read(file->private_data, ctx->pos, &to,
+					   &err);
+			if (err)
+				return err;
+			if (n == 0)
+				return 0;
+
+			rdir->head = 0;
+			rdir->tail = n;
+		}
+		while (rdir->head < rdir->tail) {
+			err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
+					  rdir->tail - rdir->head, &st);
+			if (err <= 0) {
+				p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
+				return -EIO;
+			}
+
+			over = !dir_emit(ctx, st.name, strlen(st.name),
+					 v9fs_qid2ino(&st.qid), dt_type(&st));
+			p9stat_free(&st);
+			if (over)
+				return 0;
+
+			rdir->head += err;
+			ctx->pos += err;
+		}
+	}
+}
+
+/**
+ * v9fs_dir_readdir_dotl - iterate through a directory
+ * @file: opened file structure
+ * @ctx: actor we feed the entries to
+ *
+ */
+static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
+{
+	int err = 0;
+	struct p9_fid *fid;
+	int buflen;
+	struct p9_rdir *rdir;
+	struct p9_dirent curdirent;
+
+	p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
+	fid = file->private_data;
+
+	buflen = fid->clnt->msize - P9_READDIRHDRSZ;
+
+	rdir = v9fs_alloc_rdir_buf(file, buflen);
+	if (!rdir)
+		return -ENOMEM;
+
+	while (1) {
+		if (rdir->tail == rdir->head) {
+			err = p9_client_readdir(fid, rdir->buf, buflen,
+						ctx->pos);
+			if (err <= 0)
+				return err;
+
+			rdir->head = 0;
+			rdir->tail = err;
+		}
+
+		while (rdir->head < rdir->tail) {
+
+			err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
+					    rdir->tail - rdir->head,
+					    &curdirent);
+			if (err < 0) {
+				p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
+				return -EIO;
+			}
+
+			if (!dir_emit(ctx, curdirent.d_name,
+				      strlen(curdirent.d_name),
+				      v9fs_qid2ino(&curdirent.qid),
+				      curdirent.d_type))
+				return 0;
+
+			ctx->pos = curdirent.d_off;
+			rdir->head += err;
+		}
+	}
+}
+
+
+/**
+ * v9fs_dir_release - close a directory
+ * @inode: inode of the directory
+ * @filp: file pointer to a directory
+ *
+ */
+
+int v9fs_dir_release(struct inode *inode, struct file *filp)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_fid *fid;
+	__le32 version;
+	loff_t i_size;
+
+	fid = filp->private_data;
+	p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
+		 inode, filp, fid ? fid->fid : -1);
+	if (fid) {
+		spin_lock(&inode->i_lock);
+		hlist_del(&fid->ilist);
+		spin_unlock(&inode->i_lock);
+		p9_fid_put(fid);
+	}
+
+	if ((filp->f_mode & FMODE_WRITE)) {
+		version = cpu_to_le32(v9inode->qid.version);
+		i_size = i_size_read(inode);
+		fscache_unuse_cookie(v9fs_inode_cookie(v9inode),
+				     &version, &i_size);
+	} else {
+		fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL);
+	}
+	return 0;
+}
+
+const struct file_operations v9fs_dir_operations = {
+	.read = generic_read_dir,
+	.llseek = generic_file_llseek,
+	.iterate_shared = v9fs_dir_readdir,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+};
+
+const struct file_operations v9fs_dir_operations_dotl = {
+	.read = generic_read_dir,
+	.llseek = generic_file_llseek,
+	.iterate_shared = v9fs_dir_readdir_dotl,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.fsync = v9fs_file_fsync_dotl,
+};
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
new file mode 100644
index 000000000..aec43ba83
--- /dev/null
+++ b/fs/9p/vfs_file.c
@@ -0,0 +1,711 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contians vfs file ops for 9P2000.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/inet.h>
+#include <linux/list.h>
+#include <linux/pagemap.h>
+#include <linux/utsname.h>
+#include <linux/uaccess.h>
+#include <linux/idr.h>
+#include <linux/uio.h>
+#include <linux/slab.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+#include "cache.h"
+
+static const struct vm_operations_struct v9fs_file_vm_ops;
+static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
+
+/**
+ * v9fs_file_open - open a file (or directory)
+ * @inode: inode to be opened
+ * @file: file being opened
+ *
+ */
+
+int v9fs_file_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct v9fs_inode *v9inode;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid, *writeback_fid;
+	int omode;
+
+	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
+	v9inode = V9FS_I(inode);
+	v9ses = v9fs_inode2v9ses(inode);
+	if (v9fs_proto_dotl(v9ses))
+		omode = v9fs_open_to_dotl_flags(file->f_flags);
+	else
+		omode = v9fs_uflags2omode(file->f_flags,
+					v9fs_proto_dotu(v9ses));
+	fid = file->private_data;
+	if (!fid) {
+		fid = v9fs_fid_clone(file_dentry(file));
+		if (IS_ERR(fid))
+			return PTR_ERR(fid);
+
+		err = p9_client_open(fid, omode);
+		if (err < 0) {
+			p9_fid_put(fid);
+			return err;
+		}
+		if ((file->f_flags & O_APPEND) &&
+			(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
+			generic_file_llseek(file, 0, SEEK_END);
+
+		file->private_data = fid;
+	}
+
+	mutex_lock(&v9inode->v_mutex);
+	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
+	    !v9inode->writeback_fid &&
+	    ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
+		/*
+		 * clone a fid and add it to writeback_fid
+		 * we do it during open time instead of
+		 * page dirty time via write_begin/page_mkwrite
+		 * because we want write after unlink usecase
+		 * to work.
+		 */
+		writeback_fid = v9fs_writeback_fid(file_dentry(file));
+		if (IS_ERR(writeback_fid)) {
+			err = PTR_ERR(writeback_fid);
+			mutex_unlock(&v9inode->v_mutex);
+			goto out_error;
+		}
+		v9inode->writeback_fid = (void *) writeback_fid;
+	}
+	mutex_unlock(&v9inode->v_mutex);
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+		fscache_use_cookie(v9fs_inode_cookie(v9inode),
+				   file->f_mode & FMODE_WRITE);
+	v9fs_open_fid_add(inode, &fid);
+	return 0;
+out_error:
+	p9_fid_put(file->private_data);
+	file->private_data = NULL;
+	return err;
+}
+
+/**
+ * v9fs_file_lock - lock a file (or directory)
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
+ *
+ * Bugs: this looks like a local only lock, we should extend into 9P
+ *       by using open exclusive
+ */
+
+static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+	struct inode *inode = file_inode(filp);
+
+	p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
+
+	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
+		filemap_write_and_wait(inode->i_mapping);
+		invalidate_mapping_pages(&inode->i_data, 0, -1);
+	}
+
+	return 0;
+}
+
+static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+	struct p9_flock flock;
+	struct p9_fid *fid;
+	uint8_t status = P9_LOCK_ERROR;
+	int res = 0;
+	unsigned char fl_type;
+	struct v9fs_session_info *v9ses;
+
+	fid = filp->private_data;
+	BUG_ON(fid == NULL);
+
+	BUG_ON((fl->fl_flags & FL_POSIX) != FL_POSIX);
+
+	res = locks_lock_file_wait(filp, fl);
+	if (res < 0)
+		goto out;
+
+	/* convert posix lock to p9 tlock args */
+	memset(&flock, 0, sizeof(flock));
+	/* map the lock type */
+	switch (fl->fl_type) {
+	case F_RDLCK:
+		flock.type = P9_LOCK_TYPE_RDLCK;
+		break;
+	case F_WRLCK:
+		flock.type = P9_LOCK_TYPE_WRLCK;
+		break;
+	case F_UNLCK:
+		flock.type = P9_LOCK_TYPE_UNLCK;
+		break;
+	}
+	flock.start = fl->fl_start;
+	if (fl->fl_end == OFFSET_MAX)
+		flock.length = 0;
+	else
+		flock.length = fl->fl_end - fl->fl_start + 1;
+	flock.proc_id = fl->fl_pid;
+	flock.client_id = fid->clnt->name;
+	if (IS_SETLKW(cmd))
+		flock.flags = P9_LOCK_FLAGS_BLOCK;
+
+	v9ses = v9fs_inode2v9ses(file_inode(filp));
+
+	/*
+	 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
+	 * for lock request, keep on trying
+	 */
+	for (;;) {
+		res = p9_client_lock_dotl(fid, &flock, &status);
+		if (res < 0)
+			goto out_unlock;
+
+		if (status != P9_LOCK_BLOCKED)
+			break;
+		if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
+			break;
+		if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
+				!= 0)
+			break;
+		/*
+		 * p9_client_lock_dotl overwrites flock.client_id with the
+		 * server message, free and reuse the client name
+		 */
+		if (flock.client_id != fid->clnt->name) {
+			kfree(flock.client_id);
+			flock.client_id = fid->clnt->name;
+		}
+	}
+
+	/* map 9p status to VFS status */
+	switch (status) {
+	case P9_LOCK_SUCCESS:
+		res = 0;
+		break;
+	case P9_LOCK_BLOCKED:
+		res = -EAGAIN;
+		break;
+	default:
+		WARN_ONCE(1, "unknown lock status code: %d\n", status);
+		fallthrough;
+	case P9_LOCK_ERROR:
+	case P9_LOCK_GRACE:
+		res = -ENOLCK;
+		break;
+	}
+
+out_unlock:
+	/*
+	 * incase server returned error for lock request, revert
+	 * it locally
+	 */
+	if (res < 0 && fl->fl_type != F_UNLCK) {
+		fl_type = fl->fl_type;
+		fl->fl_type = F_UNLCK;
+		/* Even if this fails we want to return the remote error */
+		locks_lock_file_wait(filp, fl);
+		fl->fl_type = fl_type;
+	}
+	if (flock.client_id != fid->clnt->name)
+		kfree(flock.client_id);
+out:
+	return res;
+}
+
+static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
+{
+	struct p9_getlock glock;
+	struct p9_fid *fid;
+	int res = 0;
+
+	fid = filp->private_data;
+	BUG_ON(fid == NULL);
+
+	posix_test_lock(filp, fl);
+	/*
+	 * if we have a conflicting lock locally, no need to validate
+	 * with server
+	 */
+	if (fl->fl_type != F_UNLCK)
+		return res;
+
+	/* convert posix lock to p9 tgetlock args */
+	memset(&glock, 0, sizeof(glock));
+	glock.type  = P9_LOCK_TYPE_UNLCK;
+	glock.start = fl->fl_start;
+	if (fl->fl_end == OFFSET_MAX)
+		glock.length = 0;
+	else
+		glock.length = fl->fl_end - fl->fl_start + 1;
+	glock.proc_id = fl->fl_pid;
+	glock.client_id = fid->clnt->name;
+
+	res = p9_client_getlock_dotl(fid, &glock);
+	if (res < 0)
+		goto out;
+	/* map 9p lock type to os lock type */
+	switch (glock.type) {
+	case P9_LOCK_TYPE_RDLCK:
+		fl->fl_type = F_RDLCK;
+		break;
+	case P9_LOCK_TYPE_WRLCK:
+		fl->fl_type = F_WRLCK;
+		break;
+	case P9_LOCK_TYPE_UNLCK:
+		fl->fl_type = F_UNLCK;
+		break;
+	}
+	if (glock.type != P9_LOCK_TYPE_UNLCK) {
+		fl->fl_start = glock.start;
+		if (glock.length == 0)
+			fl->fl_end = OFFSET_MAX;
+		else
+			fl->fl_end = glock.start + glock.length - 1;
+		fl->fl_pid = -glock.proc_id;
+	}
+out:
+	if (glock.client_id != fid->clnt->name)
+		kfree(glock.client_id);
+	return res;
+}
+
+/**
+ * v9fs_file_lock_dotl - lock a file (or directory)
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
+ *
+ */
+
+static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
+{
+	struct inode *inode = file_inode(filp);
+	int ret = -ENOLCK;
+
+	p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
+		 filp, cmd, fl, filp);
+
+	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
+		filemap_write_and_wait(inode->i_mapping);
+		invalidate_mapping_pages(&inode->i_data, 0, -1);
+	}
+
+	if (IS_SETLK(cmd) || IS_SETLKW(cmd))
+		ret = v9fs_file_do_lock(filp, cmd, fl);
+	else if (IS_GETLK(cmd))
+		ret = v9fs_file_getlock(filp, fl);
+	else
+		ret = -EINVAL;
+	return ret;
+}
+
+/**
+ * v9fs_file_flock_dotl - lock a file
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
+ *
+ */
+
+static int v9fs_file_flock_dotl(struct file *filp, int cmd,
+	struct file_lock *fl)
+{
+	struct inode *inode = file_inode(filp);
+	int ret = -ENOLCK;
+
+	p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
+		 filp, cmd, fl, filp);
+
+	if (!(fl->fl_flags & FL_FLOCK))
+		goto out_err;
+
+	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
+		filemap_write_and_wait(inode->i_mapping);
+		invalidate_mapping_pages(&inode->i_data, 0, -1);
+	}
+	/* Convert flock to posix lock */
+	fl->fl_flags |= FL_POSIX;
+	fl->fl_flags ^= FL_FLOCK;
+
+	if (IS_SETLK(cmd) | IS_SETLKW(cmd))
+		ret = v9fs_file_do_lock(filp, cmd, fl);
+	else
+		ret = -EINVAL;
+out_err:
+	return ret;
+}
+
+/**
+ * v9fs_file_read_iter - read from a file
+ * @iocb: The operation parameters
+ * @to: The buffer to read into
+ *
+ */
+static ssize_t
+v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct p9_fid *fid = iocb->ki_filp->private_data;
+	int ret, err = 0;
+
+	p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n",
+		 iov_iter_count(to), iocb->ki_pos);
+
+	if (iocb->ki_filp->f_flags & O_NONBLOCK)
+		ret = p9_client_read_once(fid, iocb->ki_pos, to, &err);
+	else
+		ret = p9_client_read(fid, iocb->ki_pos, to, &err);
+	if (!ret)
+		return err;
+
+	iocb->ki_pos += ret;
+	return ret;
+}
+
+/**
+ * v9fs_file_write_iter - write to a file
+ * @iocb: The operation parameters
+ * @from: The data to write
+ *
+ */
+static ssize_t
+v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	ssize_t retval;
+	loff_t origin;
+	int err = 0;
+
+	retval = generic_write_checks(iocb, from);
+	if (retval <= 0)
+		return retval;
+
+	origin = iocb->ki_pos;
+	retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err);
+	if (retval > 0) {
+		struct inode *inode = file_inode(file);
+		loff_t i_size;
+		unsigned long pg_start, pg_end;
+
+		pg_start = origin >> PAGE_SHIFT;
+		pg_end = (origin + retval - 1) >> PAGE_SHIFT;
+		if (inode->i_mapping && inode->i_mapping->nrpages)
+			invalidate_inode_pages2_range(inode->i_mapping,
+						      pg_start, pg_end);
+		iocb->ki_pos += retval;
+		i_size = i_size_read(inode);
+		if (iocb->ki_pos > i_size) {
+			inode_add_bytes(inode, iocb->ki_pos - i_size);
+			/*
+			 * Need to serialize against i_size_write() in
+			 * v9fs_stat2inode()
+			 */
+			v9fs_i_size_write(inode, iocb->ki_pos);
+		}
+		return retval;
+	}
+	return err;
+}
+
+static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
+			   int datasync)
+{
+	struct p9_fid *fid;
+	struct inode *inode = filp->f_mapping->host;
+	struct p9_wstat wstat;
+	int retval;
+
+	retval = file_write_and_wait_range(filp, start, end);
+	if (retval)
+		return retval;
+
+	inode_lock(inode);
+	p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
+
+	fid = filp->private_data;
+	v9fs_blank_wstat(&wstat);
+
+	retval = p9_client_wstat(fid, &wstat);
+	inode_unlock(inode);
+
+	return retval;
+}
+
+int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
+			 int datasync)
+{
+	struct p9_fid *fid;
+	struct inode *inode = filp->f_mapping->host;
+	int retval;
+
+	retval = file_write_and_wait_range(filp, start, end);
+	if (retval)
+		return retval;
+
+	inode_lock(inode);
+	p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
+
+	fid = filp->private_data;
+
+	retval = p9_client_fsync(fid, datasync);
+	inode_unlock(inode);
+
+	return retval;
+}
+
+static int
+v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	int retval;
+
+
+	retval = generic_file_mmap(filp, vma);
+	if (!retval)
+		vma->vm_ops = &v9fs_file_vm_ops;
+
+	return retval;
+}
+
+static int
+v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	int retval;
+	struct inode *inode;
+	struct v9fs_inode *v9inode;
+	struct p9_fid *fid;
+
+	inode = file_inode(filp);
+	v9inode = V9FS_I(inode);
+	mutex_lock(&v9inode->v_mutex);
+	if (!v9inode->writeback_fid &&
+	    (vma->vm_flags & VM_SHARED) &&
+	    (vma->vm_flags & VM_WRITE)) {
+		/*
+		 * clone a fid and add it to writeback_fid
+		 * we do it during mmap instead of
+		 * page dirty time via write_begin/page_mkwrite
+		 * because we want write after unlink usecase
+		 * to work.
+		 */
+		fid = v9fs_writeback_fid(file_dentry(filp));
+		if (IS_ERR(fid)) {
+			retval = PTR_ERR(fid);
+			mutex_unlock(&v9inode->v_mutex);
+			return retval;
+		}
+		v9inode->writeback_fid = (void *) fid;
+	}
+	mutex_unlock(&v9inode->v_mutex);
+
+	retval = generic_file_mmap(filp, vma);
+	if (!retval)
+		vma->vm_ops = &v9fs_mmap_file_vm_ops;
+
+	return retval;
+}
+
+static vm_fault_t
+v9fs_vm_page_mkwrite(struct vm_fault *vmf)
+{
+	struct v9fs_inode *v9inode;
+	struct folio *folio = page_folio(vmf->page);
+	struct file *filp = vmf->vma->vm_file;
+	struct inode *inode = file_inode(filp);
+
+
+	p9_debug(P9_DEBUG_VFS, "folio %p fid %lx\n",
+		 folio, (unsigned long)filp->private_data);
+
+	v9inode = V9FS_I(inode);
+
+	/* Wait for the page to be written to the cache before we allow it to
+	 * be modified.  We then assume the entire page will need writing back.
+	 */
+#ifdef CONFIG_9P_FSCACHE
+	if (folio_test_fscache(folio) &&
+	    folio_wait_fscache_killable(folio) < 0)
+		return VM_FAULT_NOPAGE;
+#endif
+
+	/* Update file times before taking page lock */
+	file_update_time(filp);
+
+	BUG_ON(!v9inode->writeback_fid);
+	if (folio_lock_killable(folio) < 0)
+		return VM_FAULT_RETRY;
+	if (folio_mapping(folio) != inode->i_mapping)
+		goto out_unlock;
+	folio_wait_stable(folio);
+
+	return VM_FAULT_LOCKED;
+out_unlock:
+	folio_unlock(folio);
+	return VM_FAULT_NOPAGE;
+}
+
+/**
+ * v9fs_mmap_file_read_iter - read from a file
+ * @iocb: The operation parameters
+ * @to: The buffer to read into
+ *
+ */
+static ssize_t
+v9fs_mmap_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	/* TODO: Check if there are dirty pages */
+	return v9fs_file_read_iter(iocb, to);
+}
+
+/**
+ * v9fs_mmap_file_write_iter - write to a file
+ * @iocb: The operation parameters
+ * @from: The data to write
+ *
+ */
+static ssize_t
+v9fs_mmap_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	/*
+	 * TODO: invalidate mmaps on filp's inode between
+	 * offset and offset+count
+	 */
+	return v9fs_file_write_iter(iocb, from);
+}
+
+static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
+{
+	struct inode *inode;
+
+	struct writeback_control wbc = {
+		.nr_to_write = LONG_MAX,
+		.sync_mode = WB_SYNC_ALL,
+		.range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,
+		 /* absolute end, byte at end included */
+		.range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +
+			(vma->vm_end - vma->vm_start - 1),
+	};
+
+	if (!(vma->vm_flags & VM_SHARED))
+		return;
+
+	p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
+
+	inode = file_inode(vma->vm_file);
+	filemap_fdatawrite_wbc(inode->i_mapping, &wbc);
+}
+
+
+static const struct vm_operations_struct v9fs_file_vm_ops = {
+	.fault = filemap_fault,
+	.map_pages = filemap_map_pages,
+	.page_mkwrite = v9fs_vm_page_mkwrite,
+};
+
+static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
+	.close = v9fs_mmap_vm_close,
+	.fault = filemap_fault,
+	.map_pages = filemap_map_pages,
+	.page_mkwrite = v9fs_vm_page_mkwrite,
+};
+
+
+const struct file_operations v9fs_cached_file_operations = {
+	.llseek = generic_file_llseek,
+	.read_iter = generic_file_read_iter,
+	.write_iter = generic_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock,
+	.mmap = v9fs_file_mmap,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync,
+};
+
+const struct file_operations v9fs_cached_file_operations_dotl = {
+	.llseek = generic_file_llseek,
+	.read_iter = generic_file_read_iter,
+	.write_iter = generic_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock_dotl,
+	.flock = v9fs_file_flock_dotl,
+	.mmap = v9fs_file_mmap,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync_dotl,
+};
+
+const struct file_operations v9fs_file_operations = {
+	.llseek = generic_file_llseek,
+	.read_iter = v9fs_file_read_iter,
+	.write_iter = v9fs_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock,
+	.mmap = generic_file_readonly_mmap,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync,
+};
+
+const struct file_operations v9fs_file_operations_dotl = {
+	.llseek = generic_file_llseek,
+	.read_iter = v9fs_file_read_iter,
+	.write_iter = v9fs_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock_dotl,
+	.flock = v9fs_file_flock_dotl,
+	.mmap = generic_file_readonly_mmap,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync_dotl,
+};
+
+const struct file_operations v9fs_mmap_file_operations = {
+	.llseek = generic_file_llseek,
+	.read_iter = v9fs_mmap_file_read_iter,
+	.write_iter = v9fs_mmap_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock,
+	.mmap = v9fs_mmap_file_mmap,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync,
+};
+
+const struct file_operations v9fs_mmap_file_operations_dotl = {
+	.llseek = generic_file_llseek,
+	.read_iter = v9fs_mmap_file_read_iter,
+	.write_iter = v9fs_mmap_file_write_iter,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock_dotl,
+	.flock = v9fs_file_flock_dotl,
+	.mmap = v9fs_mmap_file_mmap,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.fsync = v9fs_file_fsync_dotl,
+};
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
new file mode 100644
index 000000000..4d1a4a8d9
--- /dev/null
+++ b/fs/9p/vfs_inode.c
@@ -0,0 +1,1465 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contains vfs inode ops for the 9P2000 protocol.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/pagemap.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/inet.h>
+#include <linux/namei.h>
+#include <linux/idr.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+#include "cache.h"
+#include "xattr.h"
+#include "acl.h"
+
+static const struct inode_operations v9fs_dir_inode_operations;
+static const struct inode_operations v9fs_dir_inode_operations_dotu;
+static const struct inode_operations v9fs_file_inode_operations;
+static const struct inode_operations v9fs_symlink_inode_operations;
+
+/**
+ * unixmode2p9mode - convert unix mode bits to plan 9
+ * @v9ses: v9fs session information
+ * @mode: mode to convert
+ *
+ */
+
+static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
+{
+	int res;
+
+	res = mode & 0777;
+	if (S_ISDIR(mode))
+		res |= P9_DMDIR;
+	if (v9fs_proto_dotu(v9ses)) {
+		if (v9ses->nodev == 0) {
+			if (S_ISSOCK(mode))
+				res |= P9_DMSOCKET;
+			if (S_ISFIFO(mode))
+				res |= P9_DMNAMEDPIPE;
+			if (S_ISBLK(mode))
+				res |= P9_DMDEVICE;
+			if (S_ISCHR(mode))
+				res |= P9_DMDEVICE;
+		}
+
+		if ((mode & S_ISUID) == S_ISUID)
+			res |= P9_DMSETUID;
+		if ((mode & S_ISGID) == S_ISGID)
+			res |= P9_DMSETGID;
+		if ((mode & S_ISVTX) == S_ISVTX)
+			res |= P9_DMSETVTX;
+	}
+	return res;
+}
+
+/**
+ * p9mode2perm- convert plan9 mode bits to unix permission bits
+ * @v9ses: v9fs session information
+ * @stat: p9_wstat from which mode need to be derived
+ *
+ */
+static int p9mode2perm(struct v9fs_session_info *v9ses,
+		       struct p9_wstat *stat)
+{
+	int res;
+	int mode = stat->mode;
+
+	res = mode & S_IALLUGO;
+	if (v9fs_proto_dotu(v9ses)) {
+		if ((mode & P9_DMSETUID) == P9_DMSETUID)
+			res |= S_ISUID;
+
+		if ((mode & P9_DMSETGID) == P9_DMSETGID)
+			res |= S_ISGID;
+
+		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
+			res |= S_ISVTX;
+	}
+	return res;
+}
+
+/**
+ * p9mode2unixmode- convert plan9 mode bits to unix mode bits
+ * @v9ses: v9fs session information
+ * @stat: p9_wstat from which mode need to be derived
+ * @rdev: major number, minor number in case of device files.
+ *
+ */
+static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
+			       struct p9_wstat *stat, dev_t *rdev)
+{
+	int res, r;
+	u32 mode = stat->mode;
+
+	*rdev = 0;
+	res = p9mode2perm(v9ses, stat);
+
+	if ((mode & P9_DMDIR) == P9_DMDIR)
+		res |= S_IFDIR;
+	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
+		res |= S_IFLNK;
+	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
+		 && (v9ses->nodev == 0))
+		res |= S_IFSOCK;
+	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
+		 && (v9ses->nodev == 0))
+		res |= S_IFIFO;
+	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
+		 && (v9ses->nodev == 0)) {
+		char type = 0;
+		int major = -1, minor = -1;
+
+		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
+		if (r != 3) {
+			p9_debug(P9_DEBUG_ERROR,
+				 "invalid device string, umode will be bogus: %s\n",
+				 stat->extension);
+			return res;
+		}
+		switch (type) {
+		case 'c':
+			res |= S_IFCHR;
+			break;
+		case 'b':
+			res |= S_IFBLK;
+			break;
+		default:
+			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
+				 type, stat->extension);
+		}
+		*rdev = MKDEV(major, minor);
+	} else
+		res |= S_IFREG;
+
+	return res;
+}
+
+/**
+ * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
+ * @uflags: flags to convert
+ * @extended: if .u extensions are active
+ */
+
+int v9fs_uflags2omode(int uflags, int extended)
+{
+	int ret;
+
+	ret = 0;
+	switch (uflags&3) {
+	default:
+	case O_RDONLY:
+		ret = P9_OREAD;
+		break;
+
+	case O_WRONLY:
+		ret = P9_OWRITE;
+		break;
+
+	case O_RDWR:
+		ret = P9_ORDWR;
+		break;
+	}
+
+	if (extended) {
+		if (uflags & O_EXCL)
+			ret |= P9_OEXCL;
+
+		if (uflags & O_APPEND)
+			ret |= P9_OAPPEND;
+	}
+
+	return ret;
+}
+
+/**
+ * v9fs_blank_wstat - helper function to setup a 9P stat structure
+ * @wstat: structure to initialize
+ *
+ */
+
+void
+v9fs_blank_wstat(struct p9_wstat *wstat)
+{
+	wstat->type = ~0;
+	wstat->dev = ~0;
+	wstat->qid.type = ~0;
+	wstat->qid.version = ~0;
+	*((long long *)&wstat->qid.path) = ~0;
+	wstat->mode = ~0;
+	wstat->atime = ~0;
+	wstat->mtime = ~0;
+	wstat->length = ~0;
+	wstat->name = NULL;
+	wstat->uid = NULL;
+	wstat->gid = NULL;
+	wstat->muid = NULL;
+	wstat->n_uid = INVALID_UID;
+	wstat->n_gid = INVALID_GID;
+	wstat->n_muid = INVALID_UID;
+	wstat->extension = NULL;
+}
+
+/**
+ * v9fs_alloc_inode - helper function to allocate an inode
+ * @sb: The superblock to allocate the inode from
+ */
+struct inode *v9fs_alloc_inode(struct super_block *sb)
+{
+	struct v9fs_inode *v9inode;
+
+	v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
+	if (!v9inode)
+		return NULL;
+	v9inode->writeback_fid = NULL;
+	v9inode->cache_validity = 0;
+	mutex_init(&v9inode->v_mutex);
+	return &v9inode->netfs.inode;
+}
+
+/**
+ * v9fs_free_inode - destroy an inode
+ * @inode: The inode to be freed
+ */
+
+void v9fs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
+}
+
+/*
+ * Set parameters for the netfs library
+ */
+static void v9fs_set_netfs_context(struct inode *inode)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops);
+}
+
+int v9fs_init_inode(struct v9fs_session_info *v9ses,
+		    struct inode *inode, umode_t mode, dev_t rdev)
+{
+	int err = 0;
+
+	inode_init_owner(&init_user_ns, inode, NULL, mode);
+	inode->i_blocks = 0;
+	inode->i_rdev = rdev;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+	inode->i_mapping->a_ops = &v9fs_addr_operations;
+	inode->i_private = NULL;
+
+	switch (mode & S_IFMT) {
+	case S_IFIFO:
+	case S_IFBLK:
+	case S_IFCHR:
+	case S_IFSOCK:
+		if (v9fs_proto_dotl(v9ses)) {
+			inode->i_op = &v9fs_file_inode_operations_dotl;
+		} else if (v9fs_proto_dotu(v9ses)) {
+			inode->i_op = &v9fs_file_inode_operations;
+		} else {
+			p9_debug(P9_DEBUG_ERROR,
+				 "special files without extended mode\n");
+			err = -EINVAL;
+			goto error;
+		}
+		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+		break;
+	case S_IFREG:
+		if (v9fs_proto_dotl(v9ses)) {
+			inode->i_op = &v9fs_file_inode_operations_dotl;
+			if (v9ses->cache == CACHE_LOOSE ||
+			    v9ses->cache == CACHE_FSCACHE)
+				inode->i_fop =
+					&v9fs_cached_file_operations_dotl;
+			else if (v9ses->cache == CACHE_MMAP)
+				inode->i_fop = &v9fs_mmap_file_operations_dotl;
+			else
+				inode->i_fop = &v9fs_file_operations_dotl;
+		} else {
+			inode->i_op = &v9fs_file_inode_operations;
+			if (v9ses->cache == CACHE_LOOSE ||
+			    v9ses->cache == CACHE_FSCACHE)
+				inode->i_fop =
+					&v9fs_cached_file_operations;
+			else if (v9ses->cache == CACHE_MMAP)
+				inode->i_fop = &v9fs_mmap_file_operations;
+			else
+				inode->i_fop = &v9fs_file_operations;
+		}
+
+		break;
+	case S_IFLNK:
+		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
+			p9_debug(P9_DEBUG_ERROR,
+				 "extended modes used with legacy protocol\n");
+			err = -EINVAL;
+			goto error;
+		}
+
+		if (v9fs_proto_dotl(v9ses))
+			inode->i_op = &v9fs_symlink_inode_operations_dotl;
+		else
+			inode->i_op = &v9fs_symlink_inode_operations;
+
+		break;
+	case S_IFDIR:
+		inc_nlink(inode);
+		if (v9fs_proto_dotl(v9ses))
+			inode->i_op = &v9fs_dir_inode_operations_dotl;
+		else if (v9fs_proto_dotu(v9ses))
+			inode->i_op = &v9fs_dir_inode_operations_dotu;
+		else
+			inode->i_op = &v9fs_dir_inode_operations;
+
+		if (v9fs_proto_dotl(v9ses))
+			inode->i_fop = &v9fs_dir_operations_dotl;
+		else
+			inode->i_fop = &v9fs_dir_operations;
+
+		break;
+	default:
+		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
+			 mode, mode & S_IFMT);
+		err = -EINVAL;
+		goto error;
+	}
+
+	v9fs_set_netfs_context(inode);
+error:
+	return err;
+
+}
+
+/**
+ * v9fs_get_inode - helper function to setup an inode
+ * @sb: superblock
+ * @mode: mode to setup inode with
+ * @rdev: The device numbers to set
+ */
+
+struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
+{
+	int err;
+	struct inode *inode;
+	struct v9fs_session_info *v9ses = sb->s_fs_info;
+
+	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
+
+	inode = new_inode(sb);
+	if (!inode) {
+		pr_warn("%s (%d): Problem allocating inode\n",
+			__func__, task_pid_nr(current));
+		return ERR_PTR(-ENOMEM);
+	}
+	err = v9fs_init_inode(v9ses, inode, mode, rdev);
+	if (err) {
+		iput(inode);
+		return ERR_PTR(err);
+	}
+	return inode;
+}
+
+/**
+ * v9fs_evict_inode - Remove an inode from the inode cache
+ * @inode: inode to release
+ *
+ */
+void v9fs_evict_inode(struct inode *inode)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	__le32 version;
+
+	truncate_inode_pages_final(&inode->i_data);
+	version = cpu_to_le32(v9inode->qid.version);
+	fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode,
+				      &version);
+	clear_inode(inode);
+	filemap_fdatawrite(&inode->i_data);
+
+	fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
+	/* clunk the fid stashed in writeback_fid */
+	p9_fid_put(v9inode->writeback_fid);
+	v9inode->writeback_fid = NULL;
+}
+
+static int v9fs_test_inode(struct inode *inode, void *data)
+{
+	int umode;
+	dev_t rdev;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_wstat *st = (struct p9_wstat *)data;
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+
+	umode = p9mode2unixmode(v9ses, st, &rdev);
+	/* don't match inode of different type */
+	if (inode_wrong_type(inode, umode))
+		return 0;
+
+	/* compare qid details */
+	if (memcmp(&v9inode->qid.version,
+		   &st->qid.version, sizeof(v9inode->qid.version)))
+		return 0;
+
+	if (v9inode->qid.type != st->qid.type)
+		return 0;
+
+	if (v9inode->qid.path != st->qid.path)
+		return 0;
+	return 1;
+}
+
+static int v9fs_test_new_inode(struct inode *inode, void *data)
+{
+	return 0;
+}
+
+static int v9fs_set_inode(struct inode *inode,  void *data)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_wstat *st = (struct p9_wstat *)data;
+
+	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
+	return 0;
+}
+
+static struct inode *v9fs_qid_iget(struct super_block *sb,
+				   struct p9_qid *qid,
+				   struct p9_wstat *st,
+				   int new)
+{
+	dev_t rdev;
+	int retval;
+	umode_t umode;
+	unsigned long i_ino;
+	struct inode *inode;
+	struct v9fs_session_info *v9ses = sb->s_fs_info;
+	int (*test)(struct inode *inode, void *data);
+
+	if (new)
+		test = v9fs_test_new_inode;
+	else
+		test = v9fs_test_inode;
+
+	i_ino = v9fs_qid2ino(qid);
+	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+	/*
+	 * initialize the inode with the stat info
+	 * FIXME!! we may need support for stale inodes
+	 * later.
+	 */
+	inode->i_ino = i_ino;
+	umode = p9mode2unixmode(v9ses, st, &rdev);
+	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
+	if (retval)
+		goto error;
+
+	v9fs_stat2inode(st, inode, sb, 0);
+	v9fs_cache_inode_get_cookie(inode);
+	unlock_new_inode(inode);
+	return inode;
+error:
+	iget_failed(inode);
+	return ERR_PTR(retval);
+
+}
+
+struct inode *
+v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
+		    struct super_block *sb, int new)
+{
+	struct p9_wstat *st;
+	struct inode *inode = NULL;
+
+	st = p9_client_stat(fid);
+	if (IS_ERR(st))
+		return ERR_CAST(st);
+
+	inode = v9fs_qid_iget(sb, &st->qid, st, new);
+	p9stat_free(st);
+	kfree(st);
+	return inode;
+}
+
+/**
+ * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
+ * plan 9 AT flag.
+ * @flags: flags to convert
+ */
+static int v9fs_at_to_dotl_flags(int flags)
+{
+	int rflags = 0;
+
+	if (flags & AT_REMOVEDIR)
+		rflags |= P9_DOTL_AT_REMOVEDIR;
+
+	return rflags;
+}
+
+/**
+ * v9fs_dec_count - helper functon to drop i_nlink.
+ *
+ * If a directory had nlink <= 2 (including . and ..), then we should not drop
+ * the link count, which indicates the underlying exported fs doesn't maintain
+ * nlink accurately. e.g.
+ * - overlayfs sets nlink to 1 for merged dir
+ * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
+ *   than EXT4_LINK_MAX (65000) links.
+ *
+ * @inode: inode whose nlink is being dropped
+ */
+static void v9fs_dec_count(struct inode *inode)
+{
+	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
+		drop_nlink(inode);
+}
+
+/**
+ * v9fs_remove - helper function to remove files and directories
+ * @dir: directory inode that is being deleted
+ * @dentry:  dentry that is being deleted
+ * @flags: removing a directory
+ *
+ */
+
+static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
+{
+	struct inode *inode;
+	int retval = -EOPNOTSUPP;
+	struct p9_fid *v9fid, *dfid;
+	struct v9fs_session_info *v9ses;
+
+	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
+		 dir, dentry, flags);
+
+	v9ses = v9fs_inode2v9ses(dir);
+	inode = d_inode(dentry);
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid)) {
+		retval = PTR_ERR(dfid);
+		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
+		return retval;
+	}
+	if (v9fs_proto_dotl(v9ses))
+		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
+					    v9fs_at_to_dotl_flags(flags));
+	p9_fid_put(dfid);
+	if (retval == -EOPNOTSUPP) {
+		/* Try the one based on path */
+		v9fid = v9fs_fid_clone(dentry);
+		if (IS_ERR(v9fid))
+			return PTR_ERR(v9fid);
+		retval = p9_client_remove(v9fid);
+	}
+	if (!retval) {
+		/*
+		 * directories on unlink should have zero
+		 * link count
+		 */
+		if (flags & AT_REMOVEDIR) {
+			clear_nlink(inode);
+			v9fs_dec_count(dir);
+		} else
+			v9fs_dec_count(inode);
+
+		v9fs_invalidate_inode_attr(inode);
+		v9fs_invalidate_inode_attr(dir);
+
+		/* invalidate all fids associated with dentry */
+		/* NOTE: This will not include open fids */
+		dentry->d_op->d_release(dentry);
+	}
+	return retval;
+}
+
+/**
+ * v9fs_create - Create a file
+ * @v9ses: session information
+ * @dir: directory that dentry is being created in
+ * @dentry:  dentry that is being created
+ * @extension: 9p2000.u extension string to support devices, etc.
+ * @perm: create permissions
+ * @mode: open mode
+ *
+ */
+static struct p9_fid *
+v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
+		struct dentry *dentry, char *extension, u32 perm, u8 mode)
+{
+	int err;
+	const unsigned char *name;
+	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
+	struct inode *inode;
+
+	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
+
+	err = 0;
+	name = dentry->d_name.name;
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid)) {
+		err = PTR_ERR(dfid);
+		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
+		return ERR_PTR(err);
+	}
+
+	/* clone a fid to use for creation */
+	ofid = clone_fid(dfid);
+	if (IS_ERR(ofid)) {
+		err = PTR_ERR(ofid);
+		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
+		goto error;
+	}
+
+	err = p9_client_fcreate(ofid, name, perm, mode, extension);
+	if (err < 0) {
+		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
+		goto error;
+	}
+
+	if (!(perm & P9_DMLINK)) {
+		/* now walk from the parent so we can get unopened fid */
+		fid = p9_client_walk(dfid, 1, &name, 1);
+		if (IS_ERR(fid)) {
+			err = PTR_ERR(fid);
+			p9_debug(P9_DEBUG_VFS,
+				   "p9_client_walk failed %d\n", err);
+			goto error;
+		}
+		/*
+		 * instantiate inode and assign the unopened fid to the dentry
+		 */
+		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			p9_debug(P9_DEBUG_VFS,
+				   "inode creation failed %d\n", err);
+			goto error;
+		}
+		v9fs_fid_add(dentry, &fid);
+		d_instantiate(dentry, inode);
+	}
+	p9_fid_put(dfid);
+	return ofid;
+error:
+	p9_fid_put(dfid);
+	p9_fid_put(ofid);
+	p9_fid_put(fid);
+	return ERR_PTR(err);
+}
+
+/**
+ * v9fs_vfs_create - VFS hook to create a regular file
+ * @mnt_userns: The user namespace of the mount
+ * @dir: The parent directory
+ * @dentry: The name of file to be created
+ * @mode: The UNIX file mode to set
+ * @excl: True if the file must not yet exist
+ *
+ * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
+ * for mknod(2).
+ *
+ */
+
+static int
+v9fs_vfs_create(struct user_namespace *mnt_userns, struct inode *dir,
+		struct dentry *dentry, umode_t mode, bool excl)
+{
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
+	u32 perm = unixmode2p9mode(v9ses, mode);
+	struct p9_fid *fid;
+
+	/* P9_OEXCL? */
+	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	v9fs_invalidate_inode_attr(dir);
+	p9_fid_put(fid);
+
+	return 0;
+}
+
+/**
+ * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
+ * @mnt_userns: The user namespace of the mount
+ * @dir:  inode that is being unlinked
+ * @dentry: dentry that is being unlinked
+ * @mode: mode for new directory
+ *
+ */
+
+static int v9fs_vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+			  struct dentry *dentry, umode_t mode)
+{
+	int err;
+	u32 perm;
+	struct p9_fid *fid;
+	struct v9fs_session_info *v9ses;
+
+	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
+	err = 0;
+	v9ses = v9fs_inode2v9ses(dir);
+	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
+	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		fid = NULL;
+	} else {
+		inc_nlink(dir);
+		v9fs_invalidate_inode_attr(dir);
+	}
+
+	if (fid)
+		p9_fid_put(fid);
+
+	return err;
+}
+
+/**
+ * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
+ * @dir:  inode that is being walked from
+ * @dentry: dentry that is being walked to?
+ * @flags: lookup flags (unused)
+ *
+ */
+
+struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
+				      unsigned int flags)
+{
+	struct dentry *res;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *dfid, *fid;
+	struct inode *inode;
+	const unsigned char *name;
+
+	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
+		 dir, dentry, dentry, flags);
+
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	v9ses = v9fs_inode2v9ses(dir);
+	/* We can walk d_parent because we hold the dir->i_mutex */
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid))
+		return ERR_CAST(dfid);
+
+	/*
+	 * Make sure we don't use a wrong inode due to parallel
+	 * unlink. For cached mode create calls request for new
+	 * inode. But with cache disabled, lookup should do this.
+	 */
+	name = dentry->d_name.name;
+	fid = p9_client_walk(dfid, 1, &name, 1);
+	p9_fid_put(dfid);
+	if (fid == ERR_PTR(-ENOENT))
+		inode = NULL;
+	else if (IS_ERR(fid))
+		inode = ERR_CAST(fid);
+	else if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
+	else
+		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+	/*
+	 * If we had a rename on the server and a parallel lookup
+	 * for the new name, then make sure we instantiate with
+	 * the new name. ie look up for a/b, while on server somebody
+	 * moved b under k and client parallely did a lookup for
+	 * k/b.
+	 */
+	res = d_splice_alias(inode, dentry);
+	if (!IS_ERR(fid)) {
+		if (!res)
+			v9fs_fid_add(dentry, &fid);
+		else if (!IS_ERR(res))
+			v9fs_fid_add(res, &fid);
+		else
+			p9_fid_put(fid);
+	}
+	return res;
+}
+
+static int
+v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
+		     struct file *file, unsigned int flags, umode_t mode)
+{
+	int err;
+	u32 perm;
+	struct v9fs_inode *v9inode;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid, *inode_fid;
+	struct dentry *res = NULL;
+	struct inode *inode;
+
+	if (d_in_lookup(dentry)) {
+		res = v9fs_vfs_lookup(dir, dentry, 0);
+		if (IS_ERR(res))
+			return PTR_ERR(res);
+
+		if (res)
+			dentry = res;
+	}
+
+	/* Only creates */
+	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
+		return finish_no_open(file, res);
+
+	err = 0;
+
+	v9ses = v9fs_inode2v9ses(dir);
+	perm = unixmode2p9mode(v9ses, mode);
+	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
+				v9fs_uflags2omode(flags,
+						v9fs_proto_dotu(v9ses)));
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		goto error;
+	}
+
+	v9fs_invalidate_inode_attr(dir);
+	inode = d_inode(dentry);
+	v9inode = V9FS_I(inode);
+	mutex_lock(&v9inode->v_mutex);
+	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
+	    !v9inode->writeback_fid &&
+	    ((flags & O_ACCMODE) != O_RDONLY)) {
+		/*
+		 * clone a fid and add it to writeback_fid
+		 * we do it during open time instead of
+		 * page dirty time via write_begin/page_mkwrite
+		 * because we want write after unlink usecase
+		 * to work.
+		 */
+		inode_fid = v9fs_writeback_fid(dentry);
+		if (IS_ERR(inode_fid)) {
+			err = PTR_ERR(inode_fid);
+			mutex_unlock(&v9inode->v_mutex);
+			goto error;
+		}
+		v9inode->writeback_fid = (void *) inode_fid;
+	}
+	mutex_unlock(&v9inode->v_mutex);
+	err = finish_open(file, dentry, generic_file_open);
+	if (err)
+		goto error;
+
+	file->private_data = fid;
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+		fscache_use_cookie(v9fs_inode_cookie(v9inode),
+				   file->f_mode & FMODE_WRITE);
+	v9fs_open_fid_add(inode, &fid);
+
+	file->f_mode |= FMODE_CREATED;
+out:
+	dput(res);
+	return err;
+
+error:
+	p9_fid_put(fid);
+	goto out;
+}
+
+/**
+ * v9fs_vfs_unlink - VFS unlink hook to delete an inode
+ * @i:  inode that is being unlinked
+ * @d: dentry that is being unlinked
+ *
+ */
+
+int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
+{
+	return v9fs_remove(i, d, 0);
+}
+
+/**
+ * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
+ * @i:  inode that is being unlinked
+ * @d: dentry that is being unlinked
+ *
+ */
+
+int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
+{
+	return v9fs_remove(i, d, AT_REMOVEDIR);
+}
+
+/**
+ * v9fs_vfs_rename - VFS hook to rename an inode
+ * @mnt_userns: The user namespace of the mount
+ * @old_dir:  old dir inode
+ * @old_dentry: old dentry
+ * @new_dir: new dir inode
+ * @new_dentry: new dentry
+ * @flags: RENAME_* flags
+ *
+ */
+
+int
+v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+		struct dentry *old_dentry, struct inode *new_dir,
+		struct dentry *new_dentry, unsigned int flags)
+{
+	int retval;
+	struct inode *old_inode;
+	struct inode *new_inode;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *oldfid = NULL, *dfid = NULL;
+	struct p9_fid *olddirfid = NULL;
+	struct p9_fid *newdirfid = NULL;
+	struct p9_wstat wstat;
+
+	if (flags)
+		return -EINVAL;
+
+	p9_debug(P9_DEBUG_VFS, "\n");
+	retval = 0;
+	old_inode = d_inode(old_dentry);
+	new_inode = d_inode(new_dentry);
+	v9ses = v9fs_inode2v9ses(old_inode);
+	oldfid = v9fs_fid_lookup(old_dentry);
+	if (IS_ERR(oldfid))
+		return PTR_ERR(oldfid);
+
+	dfid = v9fs_parent_fid(old_dentry);
+	olddirfid = clone_fid(dfid);
+	p9_fid_put(dfid);
+	dfid = NULL;
+
+	if (IS_ERR(olddirfid)) {
+		retval = PTR_ERR(olddirfid);
+		goto error;
+	}
+
+	dfid = v9fs_parent_fid(new_dentry);
+	newdirfid = clone_fid(dfid);
+	p9_fid_put(dfid);
+	dfid = NULL;
+
+	if (IS_ERR(newdirfid)) {
+		retval = PTR_ERR(newdirfid);
+		goto error;
+	}
+
+	down_write(&v9ses->rename_sem);
+	if (v9fs_proto_dotl(v9ses)) {
+		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
+					    newdirfid, new_dentry->d_name.name);
+		if (retval == -EOPNOTSUPP)
+			retval = p9_client_rename(oldfid, newdirfid,
+						  new_dentry->d_name.name);
+		if (retval != -EOPNOTSUPP)
+			goto error_locked;
+	}
+	if (old_dentry->d_parent != new_dentry->d_parent) {
+		/*
+		 * 9P .u can only handle file rename in the same directory
+		 */
+
+		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
+		retval = -EXDEV;
+		goto error_locked;
+	}
+	v9fs_blank_wstat(&wstat);
+	wstat.muid = v9ses->uname;
+	wstat.name = new_dentry->d_name.name;
+	retval = p9_client_wstat(oldfid, &wstat);
+
+error_locked:
+	if (!retval) {
+		if (new_inode) {
+			if (S_ISDIR(new_inode->i_mode))
+				clear_nlink(new_inode);
+			else
+				v9fs_dec_count(new_inode);
+		}
+		if (S_ISDIR(old_inode->i_mode)) {
+			if (!new_inode)
+				inc_nlink(new_dir);
+			v9fs_dec_count(old_dir);
+		}
+		v9fs_invalidate_inode_attr(old_inode);
+		v9fs_invalidate_inode_attr(old_dir);
+		v9fs_invalidate_inode_attr(new_dir);
+
+		/* successful rename */
+		d_move(old_dentry, new_dentry);
+	}
+	up_write(&v9ses->rename_sem);
+
+error:
+	p9_fid_put(newdirfid);
+	p9_fid_put(olddirfid);
+	p9_fid_put(oldfid);
+	return retval;
+}
+
+/**
+ * v9fs_vfs_getattr - retrieve file metadata
+ * @mnt_userns: The user namespace of the mount
+ * @path: Object to query
+ * @stat: metadata structure to populate
+ * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
+ * @flags: AT_STATX_xxx setting
+ *
+ */
+
+static int
+v9fs_vfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		 struct kstat *stat, u32 request_mask, unsigned int flags)
+{
+	struct dentry *dentry = path->dentry;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid;
+	struct p9_wstat *st;
+
+	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
+	v9ses = v9fs_dentry2v9ses(dentry);
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		generic_fillattr(&init_user_ns, d_inode(dentry), stat);
+		return 0;
+	}
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	st = p9_client_stat(fid);
+	p9_fid_put(fid);
+	if (IS_ERR(st))
+		return PTR_ERR(st);
+
+	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
+	generic_fillattr(&init_user_ns, d_inode(dentry), stat);
+
+	p9stat_free(st);
+	kfree(st);
+	return 0;
+}
+
+/**
+ * v9fs_vfs_setattr - set file metadata
+ * @mnt_userns: The user namespace of the mount
+ * @dentry: file whose metadata to set
+ * @iattr: metadata assignment structure
+ *
+ */
+
+static int v9fs_vfs_setattr(struct user_namespace *mnt_userns,
+			    struct dentry *dentry, struct iattr *iattr)
+{
+	int retval, use_dentry = 0;
+	struct inode *inode = d_inode(dentry);
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid = NULL;
+	struct p9_wstat wstat;
+
+	p9_debug(P9_DEBUG_VFS, "\n");
+	retval = setattr_prepare(&init_user_ns, dentry, iattr);
+	if (retval)
+		return retval;
+
+	retval = -EPERM;
+	v9ses = v9fs_dentry2v9ses(dentry);
+	if (iattr->ia_valid & ATTR_FILE) {
+		fid = iattr->ia_file->private_data;
+		WARN_ON(!fid);
+	}
+	if (!fid) {
+		fid = v9fs_fid_lookup(dentry);
+		use_dentry = 1;
+	}
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	v9fs_blank_wstat(&wstat);
+	if (iattr->ia_valid & ATTR_MODE)
+		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
+
+	if (iattr->ia_valid & ATTR_MTIME)
+		wstat.mtime = iattr->ia_mtime.tv_sec;
+
+	if (iattr->ia_valid & ATTR_ATIME)
+		wstat.atime = iattr->ia_atime.tv_sec;
+
+	if (iattr->ia_valid & ATTR_SIZE)
+		wstat.length = iattr->ia_size;
+
+	if (v9fs_proto_dotu(v9ses)) {
+		if (iattr->ia_valid & ATTR_UID)
+			wstat.n_uid = iattr->ia_uid;
+
+		if (iattr->ia_valid & ATTR_GID)
+			wstat.n_gid = iattr->ia_gid;
+	}
+
+	/* Write all dirty data */
+	if (d_is_reg(dentry))
+		filemap_write_and_wait(inode->i_mapping);
+
+	retval = p9_client_wstat(fid, &wstat);
+
+	if (use_dentry)
+		p9_fid_put(fid);
+
+	if (retval < 0)
+		return retval;
+
+	if ((iattr->ia_valid & ATTR_SIZE) &&
+	    iattr->ia_size != i_size_read(inode)) {
+		truncate_setsize(inode, iattr->ia_size);
+		fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
+	}
+
+	v9fs_invalidate_inode_attr(inode);
+
+	setattr_copy(&init_user_ns, inode, iattr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+/**
+ * v9fs_stat2inode - populate an inode structure with mistat info
+ * @stat: Plan 9 metadata (mistat) structure
+ * @inode: inode to populate
+ * @sb: superblock of filesystem
+ * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
+ *
+ */
+
+void
+v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
+		 struct super_block *sb, unsigned int flags)
+{
+	umode_t mode;
+	struct v9fs_session_info *v9ses = sb->s_fs_info;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+
+	set_nlink(inode, 1);
+
+	inode->i_atime.tv_sec = stat->atime;
+	inode->i_mtime.tv_sec = stat->mtime;
+	inode->i_ctime.tv_sec = stat->mtime;
+
+	inode->i_uid = v9ses->dfltuid;
+	inode->i_gid = v9ses->dfltgid;
+
+	if (v9fs_proto_dotu(v9ses)) {
+		inode->i_uid = stat->n_uid;
+		inode->i_gid = stat->n_gid;
+	}
+	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
+		if (v9fs_proto_dotu(v9ses)) {
+			unsigned int i_nlink;
+			/*
+			 * Hadlink support got added later to the .u extension.
+			 * So there can be a server out there that doesn't
+			 * support this even with .u extension. That would
+			 * just leave us with stat->extension being an empty
+			 * string, though.
+			 */
+			/* HARDLINKCOUNT %u */
+			if (sscanf(stat->extension,
+				   " HARDLINKCOUNT %u", &i_nlink) == 1)
+				set_nlink(inode, i_nlink);
+		}
+	}
+	mode = p9mode2perm(v9ses, stat);
+	mode |= inode->i_mode & ~S_IALLUGO;
+	inode->i_mode = mode;
+
+	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
+		v9fs_i_size_write(inode, stat->length);
+	/* not real number of blocks, but 512 byte ones ... */
+	inode->i_blocks = (stat->length + 512 - 1) >> 9;
+	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
+}
+
+/**
+ * v9fs_qid2ino - convert qid into inode number
+ * @qid: qid to hash
+ *
+ * BUG: potential for inode number collisions?
+ */
+
+ino_t v9fs_qid2ino(struct p9_qid *qid)
+{
+	u64 path = qid->path + 2;
+	ino_t i = 0;
+
+	if (sizeof(ino_t) == sizeof(path))
+		memcpy(&i, &path, sizeof(ino_t));
+	else
+		i = (ino_t) (path ^ (path >> 32));
+
+	return i;
+}
+
+/**
+ * v9fs_vfs_get_link - follow a symlink path
+ * @dentry: dentry for symlink
+ * @inode: inode for symlink
+ * @done: delayed call for when we are done with the return value
+ */
+
+static const char *v9fs_vfs_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
+{
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid;
+	struct p9_wstat *st;
+	char *res;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	if (!v9fs_proto_dotu(v9ses))
+		return ERR_PTR(-EBADF);
+
+	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
+	fid = v9fs_fid_lookup(dentry);
+
+	if (IS_ERR(fid))
+		return ERR_CAST(fid);
+
+	st = p9_client_stat(fid);
+	p9_fid_put(fid);
+	if (IS_ERR(st))
+		return ERR_CAST(st);
+
+	if (!(st->mode & P9_DMSYMLINK)) {
+		p9stat_free(st);
+		kfree(st);
+		return ERR_PTR(-EINVAL);
+	}
+	res = st->extension;
+	st->extension = NULL;
+	if (strlen(res) >= PATH_MAX)
+		res[PATH_MAX - 1] = '\0';
+
+	p9stat_free(st);
+	kfree(st);
+	set_delayed_call(done, kfree_link, res);
+	return res;
+}
+
+/**
+ * v9fs_vfs_mkspecial - create a special file
+ * @dir: inode to create special file in
+ * @dentry: dentry to create
+ * @perm: mode to create special file
+ * @extension: 9p2000.u format extension string representing special file
+ *
+ */
+
+static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
+	u32 perm, const char *extension)
+{
+	struct p9_fid *fid;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_inode2v9ses(dir);
+	if (!v9fs_proto_dotu(v9ses)) {
+		p9_debug(P9_DEBUG_ERROR, "not extended\n");
+		return -EPERM;
+	}
+
+	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
+								P9_OREAD);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	v9fs_invalidate_inode_attr(dir);
+	p9_fid_put(fid);
+	return 0;
+}
+
+/**
+ * v9fs_vfs_symlink - helper function to create symlinks
+ * @mnt_userns: The user namespace of the mount
+ * @dir: directory inode containing symlink
+ * @dentry: dentry for symlink
+ * @symname: symlink data
+ *
+ * See Also: 9P2000.u RFC for more information
+ *
+ */
+
+static int
+v9fs_vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+		 struct dentry *dentry, const char *symname)
+{
+	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
+		 dir->i_ino, dentry, symname);
+
+	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
+}
+
+#define U32_MAX_DIGITS 10
+
+/**
+ * v9fs_vfs_link - create a hardlink
+ * @old_dentry: dentry for file to link to
+ * @dir: inode destination for new link
+ * @dentry: dentry for link
+ *
+ */
+
+static int
+v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
+	      struct dentry *dentry)
+{
+	int retval;
+	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
+	struct p9_fid *oldfid;
+
+	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
+		 dir->i_ino, dentry, old_dentry);
+
+	oldfid = v9fs_fid_clone(old_dentry);
+	if (IS_ERR(oldfid))
+		return PTR_ERR(oldfid);
+
+	sprintf(name, "%d\n", oldfid->fid);
+	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
+	if (!retval) {
+		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
+		v9fs_invalidate_inode_attr(dir);
+	}
+	p9_fid_put(oldfid);
+	return retval;
+}
+
+/**
+ * v9fs_vfs_mknod - create a special file
+ * @mnt_userns: The user namespace of the mount
+ * @dir: inode destination for new link
+ * @dentry: dentry for file
+ * @mode: mode for creation
+ * @rdev: device associated with special file
+ *
+ */
+
+static int
+v9fs_vfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+	       struct dentry *dentry, umode_t mode, dev_t rdev)
+{
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
+	int retval;
+	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
+	u32 perm;
+
+	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
+		 dir->i_ino, dentry, mode,
+		 MAJOR(rdev), MINOR(rdev));
+
+	/* build extension */
+	if (S_ISBLK(mode))
+		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
+	else if (S_ISCHR(mode))
+		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
+	else
+		*name = 0;
+
+	perm = unixmode2p9mode(v9ses, mode);
+	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
+
+	return retval;
+}
+
+int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
+{
+	int umode;
+	dev_t rdev;
+	struct p9_wstat *st;
+	struct v9fs_session_info *v9ses;
+	unsigned int flags;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	st = p9_client_stat(fid);
+	if (IS_ERR(st))
+		return PTR_ERR(st);
+	/*
+	 * Don't update inode if the file type is different
+	 */
+	umode = p9mode2unixmode(v9ses, st, &rdev);
+	if (inode_wrong_type(inode, umode))
+		goto out;
+
+	/*
+	 * We don't want to refresh inode->i_size,
+	 * because we may have cached data
+	 */
+	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
+		V9FS_STAT2INODE_KEEP_ISIZE : 0;
+	v9fs_stat2inode(st, inode, inode->i_sb, flags);
+out:
+	p9stat_free(st);
+	kfree(st);
+	return 0;
+}
+
+static const struct inode_operations v9fs_dir_inode_operations_dotu = {
+	.create = v9fs_vfs_create,
+	.lookup = v9fs_vfs_lookup,
+	.atomic_open = v9fs_vfs_atomic_open,
+	.symlink = v9fs_vfs_symlink,
+	.link = v9fs_vfs_link,
+	.unlink = v9fs_vfs_unlink,
+	.mkdir = v9fs_vfs_mkdir,
+	.rmdir = v9fs_vfs_rmdir,
+	.mknod = v9fs_vfs_mknod,
+	.rename = v9fs_vfs_rename,
+	.getattr = v9fs_vfs_getattr,
+	.setattr = v9fs_vfs_setattr,
+};
+
+static const struct inode_operations v9fs_dir_inode_operations = {
+	.create = v9fs_vfs_create,
+	.lookup = v9fs_vfs_lookup,
+	.atomic_open = v9fs_vfs_atomic_open,
+	.unlink = v9fs_vfs_unlink,
+	.mkdir = v9fs_vfs_mkdir,
+	.rmdir = v9fs_vfs_rmdir,
+	.mknod = v9fs_vfs_mknod,
+	.rename = v9fs_vfs_rename,
+	.getattr = v9fs_vfs_getattr,
+	.setattr = v9fs_vfs_setattr,
+};
+
+static const struct inode_operations v9fs_file_inode_operations = {
+	.getattr = v9fs_vfs_getattr,
+	.setattr = v9fs_vfs_setattr,
+};
+
+static const struct inode_operations v9fs_symlink_inode_operations = {
+	.get_link = v9fs_vfs_get_link,
+	.getattr = v9fs_vfs_getattr,
+	.setattr = v9fs_vfs_setattr,
+};
+
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
new file mode 100644
index 000000000..5cfa4b4f0
--- /dev/null
+++ b/fs/9p/vfs_inode_dotl.c
@@ -0,0 +1,1001 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file contains vfs inode ops for the 9P2000.L protocol.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/pagemap.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/inet.h>
+#include <linux/namei.h>
+#include <linux/idr.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+#include "cache.h"
+#include "xattr.h"
+#include "acl.h"
+
+static int
+v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
+		    struct dentry *dentry, umode_t omode, dev_t rdev);
+
+/**
+ * v9fs_get_fsgid_for_create - Helper function to get the gid for a new object
+ * @dir_inode: The directory inode
+ *
+ * Helper function to get the gid for creating a
+ * new file system object. This checks the S_ISGID to determine the owning
+ * group of the new file system object.
+ */
+
+static kgid_t v9fs_get_fsgid_for_create(struct inode *dir_inode)
+{
+	BUG_ON(dir_inode == NULL);
+
+	if (dir_inode->i_mode & S_ISGID) {
+		/* set_gid bit is set.*/
+		return dir_inode->i_gid;
+	}
+	return current_fsgid();
+}
+
+static int v9fs_test_inode_dotl(struct inode *inode, void *data)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_stat_dotl *st = (struct p9_stat_dotl *)data;
+
+	/* don't match inode of different type */
+	if (inode_wrong_type(inode, st->st_mode))
+		return 0;
+
+	if (inode->i_generation != st->st_gen)
+		return 0;
+
+	/* compare qid details */
+	if (memcmp(&v9inode->qid.version,
+		   &st->qid.version, sizeof(v9inode->qid.version)))
+		return 0;
+
+	if (v9inode->qid.type != st->qid.type)
+		return 0;
+
+	if (v9inode->qid.path != st->qid.path)
+		return 0;
+	return 1;
+}
+
+/* Always get a new inode */
+static int v9fs_test_new_inode_dotl(struct inode *inode, void *data)
+{
+	return 0;
+}
+
+static int v9fs_set_inode_dotl(struct inode *inode,  void *data)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_stat_dotl *st = (struct p9_stat_dotl *)data;
+
+	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
+	inode->i_generation = st->st_gen;
+	return 0;
+}
+
+static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
+					struct p9_qid *qid,
+					struct p9_fid *fid,
+					struct p9_stat_dotl *st,
+					int new)
+{
+	int retval;
+	unsigned long i_ino;
+	struct inode *inode;
+	struct v9fs_session_info *v9ses = sb->s_fs_info;
+	int (*test)(struct inode *inode, void *data);
+
+	if (new)
+		test = v9fs_test_new_inode_dotl;
+	else
+		test = v9fs_test_inode_dotl;
+
+	i_ino = v9fs_qid2ino(qid);
+	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode_dotl, st);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+	/*
+	 * initialize the inode with the stat info
+	 * FIXME!! we may need support for stale inodes
+	 * later.
+	 */
+	inode->i_ino = i_ino;
+	retval = v9fs_init_inode(v9ses, inode,
+				 st->st_mode, new_decode_dev(st->st_rdev));
+	if (retval)
+		goto error;
+
+	v9fs_stat2inode_dotl(st, inode, 0);
+	v9fs_cache_inode_get_cookie(inode);
+	retval = v9fs_get_acl(inode, fid);
+	if (retval)
+		goto error;
+
+	unlock_new_inode(inode);
+	return inode;
+error:
+	iget_failed(inode);
+	return ERR_PTR(retval);
+
+}
+
+struct inode *
+v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses, struct p9_fid *fid,
+			 struct super_block *sb, int new)
+{
+	struct p9_stat_dotl *st;
+	struct inode *inode = NULL;
+
+	st = p9_client_getattr_dotl(fid, P9_STATS_BASIC | P9_STATS_GEN);
+	if (IS_ERR(st))
+		return ERR_CAST(st);
+
+	inode = v9fs_qid_iget_dotl(sb, &st->qid, fid, st, new);
+	kfree(st);
+	return inode;
+}
+
+struct dotl_openflag_map {
+	int open_flag;
+	int dotl_flag;
+};
+
+static int v9fs_mapped_dotl_flags(int flags)
+{
+	int i;
+	int rflags = 0;
+	struct dotl_openflag_map dotl_oflag_map[] = {
+		{ O_CREAT,	P9_DOTL_CREATE },
+		{ O_EXCL,	P9_DOTL_EXCL },
+		{ O_NOCTTY,	P9_DOTL_NOCTTY },
+		{ O_APPEND,	P9_DOTL_APPEND },
+		{ O_NONBLOCK,	P9_DOTL_NONBLOCK },
+		{ O_DSYNC,	P9_DOTL_DSYNC },
+		{ FASYNC,	P9_DOTL_FASYNC },
+		{ O_DIRECT,	P9_DOTL_DIRECT },
+		{ O_LARGEFILE,	P9_DOTL_LARGEFILE },
+		{ O_DIRECTORY,	P9_DOTL_DIRECTORY },
+		{ O_NOFOLLOW,	P9_DOTL_NOFOLLOW },
+		{ O_NOATIME,	P9_DOTL_NOATIME },
+		{ O_CLOEXEC,	P9_DOTL_CLOEXEC },
+		{ O_SYNC,	P9_DOTL_SYNC},
+	};
+	for (i = 0; i < ARRAY_SIZE(dotl_oflag_map); i++) {
+		if (flags & dotl_oflag_map[i].open_flag)
+			rflags |= dotl_oflag_map[i].dotl_flag;
+	}
+	return rflags;
+}
+
+/**
+ * v9fs_open_to_dotl_flags- convert Linux specific open flags to
+ * plan 9 open flag.
+ * @flags: flags to convert
+ */
+int v9fs_open_to_dotl_flags(int flags)
+{
+	int rflags = 0;
+
+	/*
+	 * We have same bits for P9_DOTL_READONLY, P9_DOTL_WRONLY
+	 * and P9_DOTL_NOACCESS
+	 */
+	rflags |= flags & O_ACCMODE;
+	rflags |= v9fs_mapped_dotl_flags(flags);
+
+	return rflags;
+}
+
+/**
+ * v9fs_vfs_create_dotl - VFS hook to create files for 9P2000.L protocol.
+ * @mnt_userns: The user namespace of the mount
+ * @dir: directory inode that is being created
+ * @dentry:  dentry that is being deleted
+ * @omode: create permissions
+ * @excl: True if the file must not yet exist
+ *
+ */
+static int
+v9fs_vfs_create_dotl(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t omode, bool excl)
+{
+	return v9fs_vfs_mknod_dotl(mnt_userns, dir, dentry, omode, 0);
+}
+
+static int
+v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
+			  struct file *file, unsigned int flags, umode_t omode)
+{
+	int err = 0;
+	kgid_t gid;
+	umode_t mode;
+	const unsigned char *name = NULL;
+	struct p9_qid qid;
+	struct inode *inode;
+	struct p9_fid *fid = NULL;
+	struct v9fs_inode *v9inode;
+	struct p9_fid *dfid = NULL, *ofid = NULL, *inode_fid = NULL;
+	struct v9fs_session_info *v9ses;
+	struct posix_acl *pacl = NULL, *dacl = NULL;
+	struct dentry *res = NULL;
+
+	if (d_in_lookup(dentry)) {
+		res = v9fs_vfs_lookup(dir, dentry, 0);
+		if (IS_ERR(res))
+			return PTR_ERR(res);
+
+		if (res)
+			dentry = res;
+	}
+
+	/* Only creates */
+	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
+		return	finish_no_open(file, res);
+
+	v9ses = v9fs_inode2v9ses(dir);
+
+	name = dentry->d_name.name;
+	p9_debug(P9_DEBUG_VFS, "name:%s flags:0x%x mode:0x%x\n",
+		 name, flags, omode);
+
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid)) {
+		err = PTR_ERR(dfid);
+		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
+		goto out;
+	}
+
+	/* clone a fid to use for creation */
+	ofid = clone_fid(dfid);
+	if (IS_ERR(ofid)) {
+		err = PTR_ERR(ofid);
+		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
+		goto out;
+	}
+
+	gid = v9fs_get_fsgid_for_create(dir);
+
+	mode = omode;
+	/* Update mode based on ACL value */
+	err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
+	if (err) {
+		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in creat %d\n",
+			 err);
+		goto out;
+	}
+	err = p9_client_create_dotl(ofid, name, v9fs_open_to_dotl_flags(flags),
+				    mode, gid, &qid);
+	if (err < 0) {
+		p9_debug(P9_DEBUG_VFS, "p9_client_open_dotl failed in creat %d\n",
+			 err);
+		goto out;
+	}
+	v9fs_invalidate_inode_attr(dir);
+
+	/* instantiate inode and assign the unopened fid to the dentry */
+	fid = p9_client_walk(dfid, 1, &name, 1);
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
+		goto out;
+	}
+	inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n", err);
+		goto out;
+	}
+	/* Now set the ACL based on the default value */
+	v9fs_set_create_acl(inode, fid, dacl, pacl);
+
+	v9fs_fid_add(dentry, &fid);
+	d_instantiate(dentry, inode);
+
+	v9inode = V9FS_I(inode);
+	mutex_lock(&v9inode->v_mutex);
+	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
+	    !v9inode->writeback_fid &&
+	    ((flags & O_ACCMODE) != O_RDONLY)) {
+		/*
+		 * clone a fid and add it to writeback_fid
+		 * we do it during open time instead of
+		 * page dirty time via write_begin/page_mkwrite
+		 * because we want write after unlink usecase
+		 * to work.
+		 */
+		inode_fid = v9fs_writeback_fid(dentry);
+		if (IS_ERR(inode_fid)) {
+			err = PTR_ERR(inode_fid);
+			mutex_unlock(&v9inode->v_mutex);
+			goto out;
+		}
+		v9inode->writeback_fid = (void *) inode_fid;
+	}
+	mutex_unlock(&v9inode->v_mutex);
+	/* Since we are opening a file, assign the open fid to the file */
+	err = finish_open(file, dentry, generic_file_open);
+	if (err)
+		goto out;
+	file->private_data = ofid;
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+		fscache_use_cookie(v9fs_inode_cookie(v9inode),
+				   file->f_mode & FMODE_WRITE);
+	v9fs_open_fid_add(inode, &ofid);
+	file->f_mode |= FMODE_CREATED;
+out:
+	p9_fid_put(dfid);
+	p9_fid_put(ofid);
+	p9_fid_put(fid);
+	v9fs_put_acl(dacl, pacl);
+	dput(res);
+	return err;
+}
+
+/**
+ * v9fs_vfs_mkdir_dotl - VFS mkdir hook to create a directory
+ * @mnt_userns: The user namespace of the mount
+ * @dir:  inode that is being unlinked
+ * @dentry: dentry that is being unlinked
+ * @omode: mode for new directory
+ *
+ */
+
+static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
+			       struct inode *dir, struct dentry *dentry,
+			       umode_t omode)
+{
+	int err;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid = NULL, *dfid = NULL;
+	kgid_t gid;
+	const unsigned char *name;
+	umode_t mode;
+	struct inode *inode;
+	struct p9_qid qid;
+	struct posix_acl *dacl = NULL, *pacl = NULL;
+
+	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
+	err = 0;
+	v9ses = v9fs_inode2v9ses(dir);
+
+	omode |= S_IFDIR;
+	if (dir->i_mode & S_ISGID)
+		omode |= S_ISGID;
+
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid)) {
+		err = PTR_ERR(dfid);
+		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
+		goto error;
+	}
+
+	gid = v9fs_get_fsgid_for_create(dir);
+	mode = omode;
+	/* Update mode based on ACL value */
+	err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
+	if (err) {
+		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in mkdir %d\n",
+			 err);
+		goto error;
+	}
+	name = dentry->d_name.name;
+	err = p9_client_mkdir_dotl(dfid, name, mode, gid, &qid);
+	if (err < 0)
+		goto error;
+	fid = p9_client_walk(dfid, 1, &name, 1);
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
+			 err);
+		goto error;
+	}
+
+	/* instantiate inode and assign the unopened fid to the dentry */
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
+				 err);
+			goto error;
+		}
+		v9fs_fid_add(dentry, &fid);
+		v9fs_set_create_acl(inode, fid, dacl, pacl);
+		d_instantiate(dentry, inode);
+		err = 0;
+	} else {
+		/*
+		 * Not in cached mode. No need to populate
+		 * inode with stat. We need to get an inode
+		 * so that we can set the acl with dentry
+		 */
+		inode = v9fs_get_inode(dir->i_sb, mode, 0);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			goto error;
+		}
+		v9fs_set_create_acl(inode, fid, dacl, pacl);
+		d_instantiate(dentry, inode);
+	}
+	inc_nlink(dir);
+	v9fs_invalidate_inode_attr(dir);
+error:
+	p9_fid_put(fid);
+	v9fs_put_acl(dacl, pacl);
+	p9_fid_put(dfid);
+	return err;
+}
+
+static int
+v9fs_vfs_getattr_dotl(struct user_namespace *mnt_userns,
+		      const struct path *path, struct kstat *stat,
+		      u32 request_mask, unsigned int flags)
+{
+	struct dentry *dentry = path->dentry;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid;
+	struct p9_stat_dotl *st;
+
+	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
+	v9ses = v9fs_dentry2v9ses(dentry);
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		generic_fillattr(&init_user_ns, d_inode(dentry), stat);
+		return 0;
+	}
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	/* Ask for all the fields in stat structure. Server will return
+	 * whatever it supports
+	 */
+
+	st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
+	p9_fid_put(fid);
+	if (IS_ERR(st))
+		return PTR_ERR(st);
+
+	v9fs_stat2inode_dotl(st, d_inode(dentry), 0);
+	generic_fillattr(&init_user_ns, d_inode(dentry), stat);
+	/* Change block size to what the server returned */
+	stat->blksize = st->st_blksize;
+
+	kfree(st);
+	return 0;
+}
+
+/*
+ * Attribute flags.
+ */
+#define P9_ATTR_MODE		(1 << 0)
+#define P9_ATTR_UID		(1 << 1)
+#define P9_ATTR_GID		(1 << 2)
+#define P9_ATTR_SIZE		(1 << 3)
+#define P9_ATTR_ATIME		(1 << 4)
+#define P9_ATTR_MTIME		(1 << 5)
+#define P9_ATTR_CTIME		(1 << 6)
+#define P9_ATTR_ATIME_SET	(1 << 7)
+#define P9_ATTR_MTIME_SET	(1 << 8)
+
+struct dotl_iattr_map {
+	int iattr_valid;
+	int p9_iattr_valid;
+};
+
+static int v9fs_mapped_iattr_valid(int iattr_valid)
+{
+	int i;
+	int p9_iattr_valid = 0;
+	struct dotl_iattr_map dotl_iattr_map[] = {
+		{ ATTR_MODE,		P9_ATTR_MODE },
+		{ ATTR_UID,		P9_ATTR_UID },
+		{ ATTR_GID,		P9_ATTR_GID },
+		{ ATTR_SIZE,		P9_ATTR_SIZE },
+		{ ATTR_ATIME,		P9_ATTR_ATIME },
+		{ ATTR_MTIME,		P9_ATTR_MTIME },
+		{ ATTR_CTIME,		P9_ATTR_CTIME },
+		{ ATTR_ATIME_SET,	P9_ATTR_ATIME_SET },
+		{ ATTR_MTIME_SET,	P9_ATTR_MTIME_SET },
+	};
+	for (i = 0; i < ARRAY_SIZE(dotl_iattr_map); i++) {
+		if (iattr_valid & dotl_iattr_map[i].iattr_valid)
+			p9_iattr_valid |= dotl_iattr_map[i].p9_iattr_valid;
+	}
+	return p9_iattr_valid;
+}
+
+/**
+ * v9fs_vfs_setattr_dotl - set file metadata
+ * @mnt_userns: The user namespace of the mount
+ * @dentry: file whose metadata to set
+ * @iattr: metadata assignment structure
+ *
+ */
+
+int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
+			  struct dentry *dentry, struct iattr *iattr)
+{
+	int retval, use_dentry = 0;
+	struct p9_fid *fid = NULL;
+	struct p9_iattr_dotl p9attr = {
+		.uid = INVALID_UID,
+		.gid = INVALID_GID,
+	};
+	struct inode *inode = d_inode(dentry);
+
+	p9_debug(P9_DEBUG_VFS, "\n");
+
+	retval = setattr_prepare(&init_user_ns, dentry, iattr);
+	if (retval)
+		return retval;
+
+	p9attr.valid = v9fs_mapped_iattr_valid(iattr->ia_valid);
+	if (iattr->ia_valid & ATTR_MODE)
+		p9attr.mode = iattr->ia_mode;
+	if (iattr->ia_valid & ATTR_UID)
+		p9attr.uid = iattr->ia_uid;
+	if (iattr->ia_valid & ATTR_GID)
+		p9attr.gid = iattr->ia_gid;
+	if (iattr->ia_valid & ATTR_SIZE)
+		p9attr.size = iattr->ia_size;
+	if (iattr->ia_valid & ATTR_ATIME_SET) {
+		p9attr.atime_sec = iattr->ia_atime.tv_sec;
+		p9attr.atime_nsec = iattr->ia_atime.tv_nsec;
+	}
+	if (iattr->ia_valid & ATTR_MTIME_SET) {
+		p9attr.mtime_sec = iattr->ia_mtime.tv_sec;
+		p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec;
+	}
+
+	if (iattr->ia_valid & ATTR_FILE) {
+		fid = iattr->ia_file->private_data;
+		WARN_ON(!fid);
+	}
+	if (!fid) {
+		fid = v9fs_fid_lookup(dentry);
+		use_dentry = 1;
+	}
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	/* Write all dirty data */
+	if (S_ISREG(inode->i_mode))
+		filemap_write_and_wait(inode->i_mapping);
+
+	retval = p9_client_setattr(fid, &p9attr);
+	if (retval < 0) {
+		if (use_dentry)
+			p9_fid_put(fid);
+		return retval;
+	}
+
+	if ((iattr->ia_valid & ATTR_SIZE) &&
+	    iattr->ia_size != i_size_read(inode))
+		truncate_setsize(inode, iattr->ia_size);
+
+	v9fs_invalidate_inode_attr(inode);
+	setattr_copy(&init_user_ns, inode, iattr);
+	mark_inode_dirty(inode);
+	if (iattr->ia_valid & ATTR_MODE) {
+		/* We also want to update ACL when we update mode bits */
+		retval = v9fs_acl_chmod(inode, fid);
+		if (retval < 0) {
+			if (use_dentry)
+				p9_fid_put(fid);
+			return retval;
+		}
+	}
+	if (use_dentry)
+		p9_fid_put(fid);
+
+	return 0;
+}
+
+/**
+ * v9fs_stat2inode_dotl - populate an inode structure with stat info
+ * @stat: stat structure
+ * @inode: inode to populate
+ * @flags: ctrl flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
+ *
+ */
+
+void
+v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
+		      unsigned int flags)
+{
+	umode_t mode;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+
+	if ((stat->st_result_mask & P9_STATS_BASIC) == P9_STATS_BASIC) {
+		inode->i_atime.tv_sec = stat->st_atime_sec;
+		inode->i_atime.tv_nsec = stat->st_atime_nsec;
+		inode->i_mtime.tv_sec = stat->st_mtime_sec;
+		inode->i_mtime.tv_nsec = stat->st_mtime_nsec;
+		inode->i_ctime.tv_sec = stat->st_ctime_sec;
+		inode->i_ctime.tv_nsec = stat->st_ctime_nsec;
+		inode->i_uid = stat->st_uid;
+		inode->i_gid = stat->st_gid;
+		set_nlink(inode, stat->st_nlink);
+
+		mode = stat->st_mode & S_IALLUGO;
+		mode |= inode->i_mode & ~S_IALLUGO;
+		inode->i_mode = mode;
+
+		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
+			v9fs_i_size_write(inode, stat->st_size);
+		inode->i_blocks = stat->st_blocks;
+	} else {
+		if (stat->st_result_mask & P9_STATS_ATIME) {
+			inode->i_atime.tv_sec = stat->st_atime_sec;
+			inode->i_atime.tv_nsec = stat->st_atime_nsec;
+		}
+		if (stat->st_result_mask & P9_STATS_MTIME) {
+			inode->i_mtime.tv_sec = stat->st_mtime_sec;
+			inode->i_mtime.tv_nsec = stat->st_mtime_nsec;
+		}
+		if (stat->st_result_mask & P9_STATS_CTIME) {
+			inode->i_ctime.tv_sec = stat->st_ctime_sec;
+			inode->i_ctime.tv_nsec = stat->st_ctime_nsec;
+		}
+		if (stat->st_result_mask & P9_STATS_UID)
+			inode->i_uid = stat->st_uid;
+		if (stat->st_result_mask & P9_STATS_GID)
+			inode->i_gid = stat->st_gid;
+		if (stat->st_result_mask & P9_STATS_NLINK)
+			set_nlink(inode, stat->st_nlink);
+		if (stat->st_result_mask & P9_STATS_MODE) {
+			mode = stat->st_mode & S_IALLUGO;
+			mode |= inode->i_mode & ~S_IALLUGO;
+			inode->i_mode = mode;
+		}
+		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE) &&
+		    stat->st_result_mask & P9_STATS_SIZE)
+			v9fs_i_size_write(inode, stat->st_size);
+		if (stat->st_result_mask & P9_STATS_BLOCKS)
+			inode->i_blocks = stat->st_blocks;
+	}
+	if (stat->st_result_mask & P9_STATS_GEN)
+		inode->i_generation = stat->st_gen;
+
+	/* Currently we don't support P9_STATS_BTIME and P9_STATS_DATA_VERSION
+	 * because the inode structure does not have fields for them.
+	 */
+	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
+}
+
+static int
+v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, const char *symname)
+{
+	int err;
+	kgid_t gid;
+	const unsigned char *name;
+	struct p9_qid qid;
+	struct inode *inode;
+	struct p9_fid *dfid;
+	struct p9_fid *fid = NULL;
+	struct v9fs_session_info *v9ses;
+
+	name = dentry->d_name.name;
+	p9_debug(P9_DEBUG_VFS, "%lu,%s,%s\n", dir->i_ino, name, symname);
+	v9ses = v9fs_inode2v9ses(dir);
+
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid)) {
+		err = PTR_ERR(dfid);
+		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
+		return err;
+	}
+
+	gid = v9fs_get_fsgid_for_create(dir);
+
+	/* Server doesn't alter fid on TSYMLINK. Hence no need to clone it. */
+	err = p9_client_symlink(dfid, name, symname, gid, &qid);
+
+	if (err < 0) {
+		p9_debug(P9_DEBUG_VFS, "p9_client_symlink failed %d\n", err);
+		goto error;
+	}
+
+	v9fs_invalidate_inode_attr(dir);
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		/* Now walk from the parent so we can get an unopened fid. */
+		fid = p9_client_walk(dfid, 1, &name, 1);
+		if (IS_ERR(fid)) {
+			err = PTR_ERR(fid);
+			p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
+				 err);
+			goto error;
+		}
+
+		/* instantiate inode and assign the unopened fid to dentry */
+		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
+				 err);
+			goto error;
+		}
+		v9fs_fid_add(dentry, &fid);
+		d_instantiate(dentry, inode);
+		err = 0;
+	} else {
+		/* Not in cached mode. No need to populate inode with stat */
+		inode = v9fs_get_inode(dir->i_sb, S_IFLNK, 0);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			goto error;
+		}
+		d_instantiate(dentry, inode);
+	}
+
+error:
+	p9_fid_put(fid);
+	p9_fid_put(dfid);
+	return err;
+}
+
+/**
+ * v9fs_vfs_link_dotl - create a hardlink for dotl
+ * @old_dentry: dentry for file to link to
+ * @dir: inode destination for new link
+ * @dentry: dentry for link
+ *
+ */
+
+static int
+v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
+		struct dentry *dentry)
+{
+	int err;
+	struct p9_fid *dfid, *oldfid;
+	struct v9fs_session_info *v9ses;
+
+	p9_debug(P9_DEBUG_VFS, "dir ino: %lu, old_name: %pd, new_name: %pd\n",
+		 dir->i_ino, old_dentry, dentry);
+
+	v9ses = v9fs_inode2v9ses(dir);
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid))
+		return PTR_ERR(dfid);
+
+	oldfid = v9fs_fid_lookup(old_dentry);
+	if (IS_ERR(oldfid)) {
+		p9_fid_put(dfid);
+		return PTR_ERR(oldfid);
+	}
+
+	err = p9_client_link(dfid, oldfid, dentry->d_name.name);
+
+	p9_fid_put(dfid);
+	p9_fid_put(oldfid);
+	if (err < 0) {
+		p9_debug(P9_DEBUG_VFS, "p9_client_link failed %d\n", err);
+		return err;
+	}
+
+	v9fs_invalidate_inode_attr(dir);
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		/* Get the latest stat info from server. */
+		struct p9_fid *fid;
+
+		fid = v9fs_fid_lookup(old_dentry);
+		if (IS_ERR(fid))
+			return PTR_ERR(fid);
+
+		v9fs_refresh_inode_dotl(fid, d_inode(old_dentry));
+		p9_fid_put(fid);
+	}
+	ihold(d_inode(old_dentry));
+	d_instantiate(dentry, d_inode(old_dentry));
+
+	return err;
+}
+
+/**
+ * v9fs_vfs_mknod_dotl - create a special file
+ * @mnt_userns: The user namespace of the mount
+ * @dir: inode destination for new link
+ * @dentry: dentry for file
+ * @omode: mode for creation
+ * @rdev: device associated with special file
+ *
+ */
+static int
+v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
+		    struct dentry *dentry, umode_t omode, dev_t rdev)
+{
+	int err;
+	kgid_t gid;
+	const unsigned char *name;
+	umode_t mode;
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid = NULL, *dfid = NULL;
+	struct inode *inode;
+	struct p9_qid qid;
+	struct posix_acl *dacl = NULL, *pacl = NULL;
+
+	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
+		 dir->i_ino, dentry, omode,
+		 MAJOR(rdev), MINOR(rdev));
+
+	v9ses = v9fs_inode2v9ses(dir);
+	dfid = v9fs_parent_fid(dentry);
+	if (IS_ERR(dfid)) {
+		err = PTR_ERR(dfid);
+		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
+		goto error;
+	}
+
+	gid = v9fs_get_fsgid_for_create(dir);
+	mode = omode;
+	/* Update mode based on ACL value */
+	err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
+	if (err) {
+		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in mknod %d\n",
+			 err);
+		goto error;
+	}
+	name = dentry->d_name.name;
+
+	err = p9_client_mknod_dotl(dfid, name, mode, rdev, gid, &qid);
+	if (err < 0)
+		goto error;
+
+	v9fs_invalidate_inode_attr(dir);
+	fid = p9_client_walk(dfid, 1, &name, 1);
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
+			 err);
+		goto error;
+	}
+
+	/* instantiate inode and assign the unopened fid to the dentry */
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
+				 err);
+			goto error;
+		}
+		v9fs_set_create_acl(inode, fid, dacl, pacl);
+		v9fs_fid_add(dentry, &fid);
+		d_instantiate(dentry, inode);
+		err = 0;
+	} else {
+		/*
+		 * Not in cached mode. No need to populate inode with stat.
+		 * socket syscall returns a fd, so we need instantiate
+		 */
+		inode = v9fs_get_inode(dir->i_sb, mode, rdev);
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			goto error;
+		}
+		v9fs_set_create_acl(inode, fid, dacl, pacl);
+		d_instantiate(dentry, inode);
+	}
+error:
+	p9_fid_put(fid);
+	v9fs_put_acl(dacl, pacl);
+	p9_fid_put(dfid);
+
+	return err;
+}
+
+/**
+ * v9fs_vfs_get_link_dotl - follow a symlink path
+ * @dentry: dentry for symlink
+ * @inode: inode for symlink
+ * @done: destructor for return value
+ */
+
+static const char *
+v9fs_vfs_get_link_dotl(struct dentry *dentry,
+		       struct inode *inode,
+		       struct delayed_call *done)
+{
+	struct p9_fid *fid;
+	char *target;
+	int retval;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
+
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return ERR_CAST(fid);
+	retval = p9_client_readlink(fid, &target);
+	p9_fid_put(fid);
+	if (retval)
+		return ERR_PTR(retval);
+	set_delayed_call(done, kfree_link, target);
+	return target;
+}
+
+int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
+{
+	struct p9_stat_dotl *st;
+	struct v9fs_session_info *v9ses;
+	unsigned int flags;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
+	if (IS_ERR(st))
+		return PTR_ERR(st);
+	/*
+	 * Don't update inode if the file type is different
+	 */
+	if (inode_wrong_type(inode, st->st_mode))
+		goto out;
+
+	/*
+	 * We don't want to refresh inode->i_size,
+	 * because we may have cached data
+	 */
+	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
+		V9FS_STAT2INODE_KEEP_ISIZE : 0;
+	v9fs_stat2inode_dotl(st, inode, flags);
+out:
+	kfree(st);
+	return 0;
+}
+
+const struct inode_operations v9fs_dir_inode_operations_dotl = {
+	.create = v9fs_vfs_create_dotl,
+	.atomic_open = v9fs_vfs_atomic_open_dotl,
+	.lookup = v9fs_vfs_lookup,
+	.link = v9fs_vfs_link_dotl,
+	.symlink = v9fs_vfs_symlink_dotl,
+	.unlink = v9fs_vfs_unlink,
+	.mkdir = v9fs_vfs_mkdir_dotl,
+	.rmdir = v9fs_vfs_rmdir,
+	.mknod = v9fs_vfs_mknod_dotl,
+	.rename = v9fs_vfs_rename,
+	.getattr = v9fs_vfs_getattr_dotl,
+	.setattr = v9fs_vfs_setattr_dotl,
+	.listxattr = v9fs_listxattr,
+	.get_acl = v9fs_iop_get_acl,
+};
+
+const struct inode_operations v9fs_file_inode_operations_dotl = {
+	.getattr = v9fs_vfs_getattr_dotl,
+	.setattr = v9fs_vfs_setattr_dotl,
+	.listxattr = v9fs_listxattr,
+	.get_acl = v9fs_iop_get_acl,
+};
+
+const struct inode_operations v9fs_symlink_inode_operations_dotl = {
+	.get_link = v9fs_vfs_get_link_dotl,
+	.getattr = v9fs_vfs_getattr_dotl,
+	.setattr = v9fs_vfs_setattr_dotl,
+	.listxattr = v9fs_listxattr,
+};
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
new file mode 100644
index 000000000..2d9ee073d
--- /dev/null
+++ b/fs/9p/vfs_super.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/inet.h>
+#include <linux/pagemap.h>
+#include <linux/mount.h>
+#include <linux/idr.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/statfs.h>
+#include <linux/magic.h>
+#include <linux/fscache.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+#include "xattr.h"
+#include "acl.h"
+
+static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
+
+/**
+ * v9fs_set_super - set the superblock
+ * @s: super block
+ * @data: file system specific data
+ *
+ */
+
+static int v9fs_set_super(struct super_block *s, void *data)
+{
+	s->s_fs_info = data;
+	return set_anon_super(s, data);
+}
+
+/**
+ * v9fs_fill_super - populate superblock with info
+ * @sb: superblock
+ * @v9ses: session information
+ * @flags: flags propagated from v9fs_mount()
+ *
+ */
+
+static int
+v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
+		int flags)
+{
+	int ret;
+
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
+	sb->s_blocksize = 1 << sb->s_blocksize_bits;
+	sb->s_magic = V9FS_MAGIC;
+	if (v9fs_proto_dotl(v9ses)) {
+		sb->s_op = &v9fs_super_ops_dotl;
+		sb->s_xattr = v9fs_xattr_handlers;
+	} else {
+		sb->s_op = &v9fs_super_ops;
+		sb->s_time_max = U32_MAX;
+	}
+
+	sb->s_time_min = 0;
+
+	ret = super_setup_bdi(sb);
+	if (ret)
+		return ret;
+
+	if (!v9ses->cache) {
+		sb->s_bdi->ra_pages = 0;
+		sb->s_bdi->io_pages = 0;
+	} else {
+		sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
+		sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
+	}
+
+	sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
+	if (!v9ses->cache)
+		sb->s_flags |= SB_SYNCHRONOUS;
+
+#ifdef CONFIG_9P_FS_POSIX_ACL
+	if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
+		sb->s_flags |= SB_POSIXACL;
+#endif
+
+	return 0;
+}
+
+/**
+ * v9fs_mount - mount a superblock
+ * @fs_type: file system type
+ * @flags: mount flags
+ * @dev_name: device name that was mounted
+ * @data: mount options
+ *
+ */
+
+static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
+		       const char *dev_name, void *data)
+{
+	struct super_block *sb = NULL;
+	struct inode *inode = NULL;
+	struct dentry *root = NULL;
+	struct v9fs_session_info *v9ses = NULL;
+	umode_t mode = 0777 | S_ISVTX;
+	struct p9_fid *fid;
+	int retval = 0;
+
+	p9_debug(P9_DEBUG_VFS, "\n");
+
+	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
+	if (!v9ses)
+		return ERR_PTR(-ENOMEM);
+
+	fid = v9fs_session_init(v9ses, dev_name, data);
+	if (IS_ERR(fid)) {
+		retval = PTR_ERR(fid);
+		goto free_session;
+	}
+
+	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
+	if (IS_ERR(sb)) {
+		retval = PTR_ERR(sb);
+		goto clunk_fid;
+	}
+	retval = v9fs_fill_super(sb, v9ses, flags);
+	if (retval)
+		goto release_sb;
+
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+		sb->s_d_op = &v9fs_cached_dentry_operations;
+	else
+		sb->s_d_op = &v9fs_dentry_operations;
+
+	inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
+	if (IS_ERR(inode)) {
+		retval = PTR_ERR(inode);
+		goto release_sb;
+	}
+
+	root = d_make_root(inode);
+	if (!root) {
+		retval = -ENOMEM;
+		goto release_sb;
+	}
+	sb->s_root = root;
+	if (v9fs_proto_dotl(v9ses)) {
+		struct p9_stat_dotl *st = NULL;
+
+		st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
+		if (IS_ERR(st)) {
+			retval = PTR_ERR(st);
+			goto release_sb;
+		}
+		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
+		v9fs_stat2inode_dotl(st, d_inode(root), 0);
+		kfree(st);
+	} else {
+		struct p9_wstat *st = NULL;
+
+		st = p9_client_stat(fid);
+		if (IS_ERR(st)) {
+			retval = PTR_ERR(st);
+			goto release_sb;
+		}
+
+		d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
+		v9fs_stat2inode(st, d_inode(root), sb, 0);
+
+		p9stat_free(st);
+		kfree(st);
+	}
+	retval = v9fs_get_acl(inode, fid);
+	if (retval)
+		goto release_sb;
+	v9fs_fid_add(root, &fid);
+
+	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
+	return dget(sb->s_root);
+
+clunk_fid:
+	p9_fid_put(fid);
+	v9fs_session_close(v9ses);
+free_session:
+	kfree(v9ses);
+	return ERR_PTR(retval);
+
+release_sb:
+	/*
+	 * we will do the session_close and root dentry release
+	 * in the below call. But we need to clunk fid, because we haven't
+	 * attached the fid to dentry so it won't get clunked
+	 * automatically.
+	 */
+	p9_fid_put(fid);
+	deactivate_locked_super(sb);
+	return ERR_PTR(retval);
+}
+
+/**
+ * v9fs_kill_super - Kill Superblock
+ * @s: superblock
+ *
+ */
+
+static void v9fs_kill_super(struct super_block *s)
+{
+	struct v9fs_session_info *v9ses = s->s_fs_info;
+
+	p9_debug(P9_DEBUG_VFS, " %p\n", s);
+
+	kill_anon_super(s);
+
+	v9fs_session_cancel(v9ses);
+	v9fs_session_close(v9ses);
+	kfree(v9ses);
+	s->s_fs_info = NULL;
+	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
+}
+
+static void
+v9fs_umount_begin(struct super_block *sb)
+{
+	struct v9fs_session_info *v9ses;
+
+	v9ses = sb->s_fs_info;
+	v9fs_session_begin_cancel(v9ses);
+}
+
+static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid;
+	struct p9_rstatfs rs;
+	int res;
+
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid)) {
+		res = PTR_ERR(fid);
+		goto done;
+	}
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	if (v9fs_proto_dotl(v9ses)) {
+		res = p9_client_statfs(fid, &rs);
+		if (res == 0) {
+			buf->f_type = rs.type;
+			buf->f_bsize = rs.bsize;
+			buf->f_blocks = rs.blocks;
+			buf->f_bfree = rs.bfree;
+			buf->f_bavail = rs.bavail;
+			buf->f_files = rs.files;
+			buf->f_ffree = rs.ffree;
+			buf->f_fsid = u64_to_fsid(rs.fsid);
+			buf->f_namelen = rs.namelen;
+		}
+		if (res != -ENOSYS)
+			goto done;
+	}
+	res = simple_statfs(dentry, buf);
+done:
+	p9_fid_put(fid);
+	return res;
+}
+
+static int v9fs_drop_inode(struct inode *inode)
+{
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+		return generic_drop_inode(inode);
+	/*
+	 * in case of non cached mode always drop the
+	 * inode because we want the inode attribute
+	 * to always match that on the server.
+	 */
+	return 1;
+}
+
+static int v9fs_write_inode(struct inode *inode,
+			    struct writeback_control *wbc)
+{
+	int ret;
+	struct p9_wstat wstat;
+	struct v9fs_inode *v9inode;
+	/*
+	 * send an fsync request to server irrespective of
+	 * wbc->sync_mode.
+	 */
+	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
+	v9inode = V9FS_I(inode);
+	if (!v9inode->writeback_fid)
+		return 0;
+	v9fs_blank_wstat(&wstat);
+
+	ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
+	if (ret < 0) {
+		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
+		return ret;
+	}
+	fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
+	return 0;
+}
+
+static int v9fs_write_inode_dotl(struct inode *inode,
+				 struct writeback_control *wbc)
+{
+	int ret;
+	struct v9fs_inode *v9inode;
+	/*
+	 * send an fsync request to server irrespective of
+	 * wbc->sync_mode.
+	 */
+	v9inode = V9FS_I(inode);
+	p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
+		 __func__, inode, v9inode->writeback_fid);
+	if (!v9inode->writeback_fid)
+		return 0;
+
+	ret = p9_client_fsync(v9inode->writeback_fid, 0);
+	if (ret < 0) {
+		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
+		return ret;
+	}
+	fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
+	return 0;
+}
+
+static const struct super_operations v9fs_super_ops = {
+	.alloc_inode = v9fs_alloc_inode,
+	.free_inode = v9fs_free_inode,
+	.statfs = simple_statfs,
+	.evict_inode = v9fs_evict_inode,
+	.show_options = v9fs_show_options,
+	.umount_begin = v9fs_umount_begin,
+	.write_inode = v9fs_write_inode,
+};
+
+static const struct super_operations v9fs_super_ops_dotl = {
+	.alloc_inode = v9fs_alloc_inode,
+	.free_inode = v9fs_free_inode,
+	.statfs = v9fs_statfs,
+	.drop_inode = v9fs_drop_inode,
+	.evict_inode = v9fs_evict_inode,
+	.show_options = v9fs_show_options,
+	.umount_begin = v9fs_umount_begin,
+	.write_inode = v9fs_write_inode_dotl,
+};
+
+struct file_system_type v9fs_fs_type = {
+	.name = "9p",
+	.mount = v9fs_mount,
+	.kill_sb = v9fs_kill_super,
+	.owner = THIS_MODULE,
+	.fs_flags = FS_RENAME_DOES_D_MOVE,
+};
+MODULE_ALIAS_FS("9p");
diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
new file mode 100644
index 000000000..3b9aa61de
--- /dev/null
+++ b/fs/9p/xattr.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/uio.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "fid.h"
+#include "xattr.h"
+
+ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
+			   void *buffer, size_t buffer_size)
+{
+	ssize_t retval;
+	u64 attr_size;
+	struct p9_fid *attr_fid;
+	struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
+	struct iov_iter to;
+	int err;
+
+	iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size);
+
+	attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
+	if (IS_ERR(attr_fid)) {
+		retval = PTR_ERR(attr_fid);
+		p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
+			 retval);
+		return retval;
+	}
+	if (attr_size > buffer_size) {
+		if (!buffer_size) /* request to get the attr_size */
+			retval = attr_size;
+		else
+			retval = -ERANGE;
+	} else {
+		iov_iter_truncate(&to, attr_size);
+		retval = p9_client_read(attr_fid, 0, &to, &err);
+		if (err)
+			retval = err;
+	}
+	p9_fid_put(attr_fid);
+	return retval;
+}
+
+
+/*
+ * v9fs_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
+		       void *buffer, size_t buffer_size)
+{
+	struct p9_fid *fid;
+	int ret;
+
+	p9_debug(P9_DEBUG_VFS, "name = '%s' value_len = %zu\n",
+		 name, buffer_size);
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+	ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
+	p9_fid_put(fid);
+
+	return ret;
+}
+
+/*
+ * v9fs_xattr_set()
+ *
+ * Create, replace or remove an extended attribute for this inode. Buffer
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int v9fs_xattr_set(struct dentry *dentry, const char *name,
+		   const void *value, size_t value_len, int flags)
+{
+	int ret;
+	struct p9_fid *fid;
+
+	fid  = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+	ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
+	p9_fid_put(fid);
+	return ret;
+}
+
+int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
+		   const void *value, size_t value_len, int flags)
+{
+	struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
+	struct iov_iter from;
+	int retval, err;
+
+	iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len);
+
+	p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
+		 name, value_len, flags);
+
+	/* Clone it */
+	fid = clone_fid(fid);
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
+
+	/*
+	 * On success fid points to xattr
+	 */
+	retval = p9_client_xattrcreate(fid, name, value_len, flags);
+	if (retval < 0)
+		p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
+			 retval);
+	else
+		p9_client_write(fid, 0, &from, &retval);
+	err = p9_fid_put(fid);
+	if (!retval && err)
+		retval = err;
+	return retval;
+}
+
+ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	/* Txattrwalk with an empty string lists xattrs instead */
+	return v9fs_xattr_get(dentry, "", buffer, buffer_size);
+}
+
+static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
+				  struct dentry *dentry, struct inode *inode,
+				  const char *name, void *buffer, size_t size)
+{
+	const char *full_name = xattr_full_name(handler, name);
+
+	return v9fs_xattr_get(dentry, full_name, buffer, size);
+}
+
+static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
+				  struct user_namespace *mnt_userns,
+				  struct dentry *dentry, struct inode *inode,
+				  const char *name, const void *value,
+				  size_t size, int flags)
+{
+	const char *full_name = xattr_full_name(handler, name);
+
+	return v9fs_xattr_set(dentry, full_name, value, size, flags);
+}
+
+static struct xattr_handler v9fs_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.get	= v9fs_xattr_handler_get,
+	.set	= v9fs_xattr_handler_set,
+};
+
+static struct xattr_handler v9fs_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.get	= v9fs_xattr_handler_get,
+	.set	= v9fs_xattr_handler_set,
+};
+
+#ifdef CONFIG_9P_FS_SECURITY
+static struct xattr_handler v9fs_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.get	= v9fs_xattr_handler_get,
+	.set	= v9fs_xattr_handler_set,
+};
+#endif
+
+const struct xattr_handler *v9fs_xattr_handlers[] = {
+	&v9fs_xattr_user_handler,
+	&v9fs_xattr_trusted_handler,
+#ifdef CONFIG_9P_FS_POSIX_ACL
+	&v9fs_xattr_acl_access_handler,
+	&v9fs_xattr_acl_default_handler,
+#endif
+#ifdef CONFIG_9P_FS_SECURITY
+	&v9fs_xattr_security_handler,
+#endif
+	NULL
+};
diff --git a/fs/9p/xattr.h b/fs/9p/xattr.h
new file mode 100644
index 000000000..3e11fc333
--- /dev/null
+++ b/fs/9p/xattr.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: LGPL-2.1 */
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ */
+#ifndef FS_9P_XATTR_H
+#define FS_9P_XATTR_H
+
+#include <linux/xattr.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+extern const struct xattr_handler *v9fs_xattr_handlers[];
+extern const struct xattr_handler v9fs_xattr_acl_access_handler;
+extern const struct xattr_handler v9fs_xattr_acl_default_handler;
+
+ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
+			   void *buffer, size_t buffer_size);
+ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
+		       void *buffer, size_t buffer_size);
+int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
+		       const void *value, size_t value_len, int flags);
+int v9fs_xattr_set(struct dentry *dentry, const char *name,
+		   const void *value, size_t value_len, int flags);
+ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer,
+		       size_t buffer_size);
+#endif /* FS_9P_XATTR_H */