9p: Reorganization of 9p file system code

This patchset moves non-filesystem interfaces of v9fs from fs/9p to net/9p.
It moves the transport, packet marshalling and connection layers to net/9p
leaving only the VFS related files in fs/9p.  This work is being done in
preparation for in-kernel 9p servers as well as alternate 9p clients (other
than VFS).

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

13 files changed, 4211 insertions, 0 deletions

diff --git a/net/9p/Kconfig b/net/9p/Kconfig
new file mode 100644
index 000000000000..66821cd64a76
--- /dev/null
+++ b/net/9p/Kconfig
@@ -0,0 +1,21 @@
+#
+# 9P protocol configuration
+#
+
+menuconfig NET_9P
+	depends on NET && EXPERIMENTAL
+	tristate "Plan 9 Resource Sharing Support (9P2000) (Experimental)"
+	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.
+
+config NET_9P_DEBUG
+	bool "Debug information"
+	depends on NET_9P
+	help
+	  Say Y if you want the 9P subsistem to log debug information.
+
diff --git a/net/9p/Makefile b/net/9p/Makefile
new file mode 100644
index 000000000000..ac46cb91900d
--- /dev/null
+++ b/net/9p/Makefile
@@ -0,0 +1,13 @@
+obj-$(CONFIG_NET_9P) := 9p.o
+
+9p-objs := \
+	mod.o \
+	trans_fd.o \
+	mux.o \
+	client.o \
+	conv.o \
+	error.o \
+	fcprint.o \
+	util.o \
+
+9p-$(CONFIG_SYSCTL) += sysctl.o
diff --git a/net/9p/client.c b/net/9p/client.c
new file mode 100644
index 000000000000..bb2b8a3af196
--- /dev/null
+++ b/net/9p/client.c
@@ -0,0 +1,965 @@
+/*
+ * net/9p/clnt.c
+ *
+ * 9P Client
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <net/9p/9p.h>
+#include <net/9p/transport.h>
+#include <net/9p/conn.h>
+#include <net/9p/client.h>
+
+static struct p9_fid *p9_fid_create(struct p9_client *clnt);
+static void p9_fid_destroy(struct p9_fid *fid);
+static struct p9_stat *p9_clone_stat(struct p9_stat *st, int dotu);
+
+struct p9_client *p9_client_create(struct p9_transport *trans, int msize,
+								   int dotu)
+{
+	int err, n;
+	struct p9_client *clnt;
+	struct p9_fcall *tc, *rc;
+	struct p9_str *version;
+
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
+	if (!clnt)
+		return ERR_PTR(-ENOMEM);
+
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p trans %p msize %d dotu %d\n",
+		clnt, trans, msize, dotu);
+	spin_lock_init(&clnt->lock);
+	clnt->trans = trans;
+	clnt->msize = msize;
+	clnt->dotu = dotu;
+	INIT_LIST_HEAD(&clnt->fidlist);
+	clnt->fidpool = p9_idpool_create();
+	if (!clnt->fidpool) {
+		err = PTR_ERR(clnt->fidpool);
+		clnt->fidpool = NULL;
+		goto error;
+	}
+
+	clnt->conn = p9_conn_create(clnt->trans, clnt->msize, &clnt->dotu);
+	if (IS_ERR(clnt->conn)) {
+		err = PTR_ERR(clnt->conn);
+		clnt->conn = NULL;
+		goto error;
+	}
+
+	tc = p9_create_tversion(clnt->msize, clnt->dotu?"9P2000.u":"9P2000");
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto error;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto error;
+
+	version = &rc->params.rversion.version;
+	if (version->len == 8 && !memcmp(version->str, "9P2000.u", 8))
+		clnt->dotu = 1;
+	else if (version->len == 6 && !memcmp(version->str, "9P2000", 6))
+		clnt->dotu = 0;
+	else {
+		err = -EREMOTEIO;
+		goto error;
+	}
+
+	n = rc->params.rversion.msize;
+	if (n < clnt->msize)
+		clnt->msize = n;
+
+	kfree(tc);
+	kfree(rc);
+	return clnt;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	p9_client_destroy(clnt);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_create);
+
+void p9_client_destroy(struct p9_client *clnt)
+{
+	struct p9_fid *fid, *fidptr;
+
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
+	if (clnt->conn) {
+		p9_conn_destroy(clnt->conn);
+		clnt->conn = NULL;
+	}
+
+	if (clnt->trans) {
+		clnt->trans->close(clnt->trans);
+		kfree(clnt->trans);
+		clnt->trans = NULL;
+	}
+
+	if (clnt->fidpool)
+		p9_idpool_destroy(clnt->fidpool);
+
+	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
+		p9_fid_destroy(fid);
+
+	kfree(clnt);
+}
+EXPORT_SYMBOL(p9_client_destroy);
+
+void p9_client_disconnect(struct p9_client *clnt)
+{
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
+	clnt->trans->status = Disconnected;
+	p9_conn_cancel(clnt->conn, -EIO);
+}
+EXPORT_SYMBOL(p9_client_disconnect);
+
+struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
+	char *uname, char *aname)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_fid *fid;
+
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p afid %d uname %s aname %s\n",
+		clnt, afid?afid->fid:-1, uname, aname);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+
+	fid = p9_fid_create(clnt);
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		fid = NULL;
+		goto error;
+	}
+
+	tc = p9_create_tattach(fid->fid, afid?afid->fid:P9_NOFID, uname, aname);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto error;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto error;
+
+	memmove(&fid->qid, &rc->params.rattach.qid, sizeof(struct p9_qid));
+	kfree(tc);
+	kfree(rc);
+	return fid;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	if (fid)
+		p9_fid_destroy(fid);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_attach);
+
+struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname, char *aname)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_fid *fid;
+
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p uname %s aname %s\n", clnt, uname,
+									aname);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+
+	fid = p9_fid_create(clnt);
+	if (IS_ERR(fid)) {
+		err = PTR_ERR(fid);
+		fid = NULL;
+		goto error;
+	}
+
+	tc = p9_create_tauth(fid->fid, uname, aname);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto error;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto error;
+
+	memmove(&fid->qid, &rc->params.rauth.qid, sizeof(struct p9_qid));
+	kfree(tc);
+	kfree(rc);
+	return fid;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	if (fid)
+		p9_fid_destroy(fid);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_auth);
+
+struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
+	int clone)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+	struct p9_fid *fid;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d nwname %d wname[0] %s\n",
+		oldfid->fid, nwname, wnames?wnames[0]:NULL);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = oldfid->clnt;
+	if (clone) {
+		fid = p9_fid_create(clnt);
+		if (IS_ERR(fid)) {
+			err = PTR_ERR(fid);
+			fid = NULL;
+			goto error;
+		}
+
+		fid->uid = oldfid->uid;
+	} else
+		fid = oldfid;
+
+	tc = p9_create_twalk(oldfid->fid, fid->fid, nwname, wnames);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto error;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err) {
+		if (rc && rc->id == P9_RWALK)
+			goto clunk_fid;
+		else
+			goto error;
+	}
+
+	if (rc->params.rwalk.nwqid != nwname) {
+		err = -ENOENT;
+		goto clunk_fid;
+	}
+
+	if (nwname)
+		memmove(&fid->qid,
+			&rc->params.rwalk.wqids[rc->params.rwalk.nwqid - 1],
+			sizeof(struct p9_qid));
+	else
+		fid->qid = oldfid->qid;
+
+	kfree(tc);
+	kfree(rc);
+	return fid;
+
+clunk_fid:
+	kfree(tc);
+	kfree(rc);
+	rc = NULL;
+	tc = p9_create_tclunk(fid->fid);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto error;
+	}
+
+	p9_conn_rpc(clnt->conn, tc, &rc);
+
+error:
+	kfree(tc);
+	kfree(rc);
+	if (fid && (fid != oldfid))
+		p9_fid_destroy(fid);
+
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_walk);
+
+int p9_client_open(struct p9_fid *fid, int mode)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d mode %d\n", fid->fid, mode);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+
+	if (fid->mode != -1)
+		return -EINVAL;
+
+	tc = p9_create_topen(fid->fid, mode);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto done;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto done;
+
+	fid->mode = mode;
+	fid->iounit = rc->params.ropen.iounit;
+
+done:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_open);
+
+int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
+		     char *extension)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d name %s perm %d mode %d\n", fid->fid,
+		name, perm, mode);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+
+	if (fid->mode != -1)
+		return -EINVAL;
+
+	tc = p9_create_tcreate(fid->fid, name, perm, mode, extension,
+							       clnt->dotu);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto done;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto done;
+
+	fid->mode = mode;
+	fid->iounit = rc->params.ropen.iounit;
+
+done:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_fcreate);
+
+int p9_client_clunk(struct p9_fid *fid)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+
+	tc = p9_create_tclunk(fid->fid);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto done;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto done;
+
+	p9_fid_destroy(fid);
+
+done:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_clunk);
+
+int p9_client_remove(struct p9_fid *fid)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+
+	tc = p9_create_tremove(fid->fid);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto done;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto done;
+
+	p9_fid_destroy(fid);
+
+done:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_remove);
+
+int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count)
+{
+	int err, n, rsize, total;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu %d\n", fid->fid,
+					(long long unsigned) offset, count);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+	total = 0;
+
+	rsize = fid->iounit;
+	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
+		rsize = clnt->msize - P9_IOHDRSZ;
+
+	do {
+		if (count < rsize)
+			rsize = count;
+
+		tc = p9_create_tread(fid->fid, offset, rsize);
+		if (IS_ERR(tc)) {
+			err = PTR_ERR(tc);
+			tc = NULL;
+			goto error;
+		}
+
+		err = p9_conn_rpc(clnt->conn, tc, &rc);
+		if (err)
+			goto error;
+
+		n = rc->params.rread.count;
+		if (n > count)
+			n = count;
+
+		memmove(data, rc->params.rread.data, n);
+		count -= n;
+		data += n;
+		offset += n;
+		total += n;
+		kfree(tc);
+		tc = NULL;
+		kfree(rc);
+		rc = NULL;
+	} while (count > 0 && n == rsize);
+
+	return total;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_read);
+
+int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count)
+{
+	int err, n, rsize, total;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
+					(long long unsigned) offset, count);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+	total = 0;
+
+	rsize = fid->iounit;
+	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
+		rsize = clnt->msize - P9_IOHDRSZ;
+
+	do {
+		if (count < rsize)
+			rsize = count;
+
+		tc = p9_create_twrite(fid->fid, offset, rsize, data);
+		if (IS_ERR(tc)) {
+			err = PTR_ERR(tc);
+			tc = NULL;
+			goto error;
+		}
+
+		err = p9_conn_rpc(clnt->conn, tc, &rc);
+		if (err)
+			goto error;
+
+		n = rc->params.rread.count;
+		count -= n;
+		data += n;
+		offset += n;
+		total += n;
+		kfree(tc);
+		tc = NULL;
+		kfree(rc);
+		rc = NULL;
+	} while (count > 0);
+
+	return total;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_write);
+
+int
+p9_client_uread(struct p9_fid *fid, char __user *data, u64 offset, u32 count)
+{
+	int err, n, rsize, total;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
+					(long long unsigned) offset, count);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+	total = 0;
+
+	rsize = fid->iounit;
+	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
+		rsize = clnt->msize - P9_IOHDRSZ;
+
+	do {
+		if (count < rsize)
+			rsize = count;
+
+		tc = p9_create_tread(fid->fid, offset, rsize);
+		if (IS_ERR(tc)) {
+			err = PTR_ERR(tc);
+			tc = NULL;
+			goto error;
+		}
+
+		err = p9_conn_rpc(clnt->conn, tc, &rc);
+		if (err)
+			goto error;
+
+		n = rc->params.rread.count;
+		if (n > count)
+			n = count;
+
+		err = copy_to_user(data, rc->params.rread.data, n);
+		if (err) {
+			err = -EFAULT;
+			goto error;
+		}
+
+		count -= n;
+		data += n;
+		offset += n;
+		total += n;
+		kfree(tc);
+		tc = NULL;
+		kfree(rc);
+		rc = NULL;
+	} while (count > 0 && n == rsize);
+
+	return total;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_uread);
+
+int
+p9_client_uwrite(struct p9_fid *fid, const char __user *data, u64 offset,
+								   u32 count)
+{
+	int err, n, rsize, total;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
+					(long long unsigned) offset, count);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+	total = 0;
+
+	rsize = fid->iounit;
+	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
+		rsize = clnt->msize - P9_IOHDRSZ;
+
+	do {
+		if (count < rsize)
+			rsize = count;
+
+		tc = p9_create_twrite_u(fid->fid, offset, rsize, data);
+		if (IS_ERR(tc)) {
+			err = PTR_ERR(tc);
+			tc = NULL;
+			goto error;
+		}
+
+		err = p9_conn_rpc(clnt->conn, tc, &rc);
+		if (err)
+			goto error;
+
+		n = rc->params.rread.count;
+		count -= n;
+		data += n;
+		offset += n;
+		total += n;
+		kfree(tc);
+		tc = NULL;
+		kfree(rc);
+		rc = NULL;
+	} while (count > 0);
+
+	return total;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_uwrite);
+
+int p9_client_readn(struct p9_fid *fid, char *data, u64 offset, u32 count)
+{
+	int n, total;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
+					(long long unsigned) offset, count);
+	n = 0;
+	total = 0;
+	while (count) {
+		n = p9_client_read(fid, data, offset, count);
+		if (n <= 0)
+			break;
+
+		data += n;
+		offset += n;
+		count -= n;
+		total += n;
+	}
+
+	if (n < 0)
+		total = n;
+
+	return total;
+}
+EXPORT_SYMBOL(p9_client_readn);
+
+struct p9_stat *p9_client_stat(struct p9_fid *fid)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+	struct p9_stat *ret;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	ret = NULL;
+	clnt = fid->clnt;
+
+	tc = p9_create_tstat(fid->fid);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto error;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+	if (err)
+		goto error;
+
+	ret = p9_clone_stat(&rc->params.rstat.stat, clnt->dotu);
+	if (IS_ERR(ret)) {
+		err = PTR_ERR(ret);
+		ret = NULL;
+		goto error;
+	}
+
+	kfree(tc);
+	kfree(rc);
+	return ret;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	kfree(ret);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_stat);
+
+int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
+{
+	int err;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	clnt = fid->clnt;
+
+	tc = p9_create_twstat(fid->fid, wst, clnt->dotu);
+	if (IS_ERR(tc)) {
+		err = PTR_ERR(tc);
+		tc = NULL;
+		goto done;
+	}
+
+	err = p9_conn_rpc(clnt->conn, tc, &rc);
+
+done:
+	kfree(tc);
+	kfree(rc);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_wstat);
+
+struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset)
+{
+	int err, n, m;
+	struct p9_fcall *tc, *rc;
+	struct p9_client *clnt;
+	struct p9_stat st, *ret;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu\n", fid->fid,
+						(long long unsigned) offset);
+	err = 0;
+	tc = NULL;
+	rc = NULL;
+	ret = NULL;
+	clnt = fid->clnt;
+
+	/* if the offset is below or above the current response, free it */
+	if (offset < fid->rdir_fpos || (fid->rdir_fcall &&
+		offset >= fid->rdir_fpos+fid->rdir_fcall->params.rread.count)) {
+		fid->rdir_pos = 0;
+		if (fid->rdir_fcall)
+			fid->rdir_fpos += fid->rdir_fcall->params.rread.count;
+
+		kfree(fid->rdir_fcall);
+		fid->rdir_fcall = NULL;
+		if (offset < fid->rdir_fpos)
+			fid->rdir_fpos = 0;
+	}
+
+	if (!fid->rdir_fcall) {
+		n = fid->iounit;
+		if (!n || n > clnt->msize-P9_IOHDRSZ)
+			n = clnt->msize - P9_IOHDRSZ;
+
+		while (1) {
+			if (fid->rdir_fcall) {
+				fid->rdir_fpos +=
+					fid->rdir_fcall->params.rread.count;
+				kfree(fid->rdir_fcall);
+				fid->rdir_fcall = NULL;
+			}
+
+			tc = p9_create_tread(fid->fid, fid->rdir_fpos, n);
+			if (IS_ERR(tc)) {
+				err = PTR_ERR(tc);
+				tc = NULL;
+				goto error;
+			}
+
+			err = p9_conn_rpc(clnt->conn, tc, &rc);
+			if (err)
+				goto error;
+
+			n = rc->params.rread.count;
+			if (n == 0)
+				goto done;
+
+			fid->rdir_fcall = rc;
+			rc = NULL;
+			if (offset >= fid->rdir_fpos &&
+						offset < fid->rdir_fpos+n)
+				break;
+		}
+
+		fid->rdir_pos = 0;
+	}
+
+	m = offset - fid->rdir_fpos;
+	if (m < 0)
+		goto done;
+
+	n = p9_deserialize_stat(fid->rdir_fcall->params.rread.data + m,
+		fid->rdir_fcall->params.rread.count - m, &st, clnt->dotu);
+
+	if (!n) {
+		err = -EIO;
+		goto error;
+	}
+
+	fid->rdir_pos += n;
+	st.size = n;
+	ret = p9_clone_stat(&st, clnt->dotu);
+	if (IS_ERR(ret)) {
+		err = PTR_ERR(ret);
+		ret = NULL;
+		goto error;
+	}
+
+done:
+	kfree(tc);
+	kfree(rc);
+	return ret;
+
+error:
+	kfree(tc);
+	kfree(rc);
+	kfree(ret);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_dirread);
+
+static struct p9_stat *p9_clone_stat(struct p9_stat *st, int dotu)
+{
+	int n;
+	char *p;
+	struct p9_stat *ret;
+
+	n = sizeof(struct p9_stat) + st->name.len + st->uid.len + st->gid.len +
+		st->muid.len;
+
+	if (dotu)
+		n += st->extension.len;
+
+	ret = kmalloc(n, GFP_KERNEL);
+	if (!ret)
+		return ERR_PTR(-ENOMEM);
+
+	memmove(ret, st, sizeof(struct p9_stat));
+	p = ((char *) ret) + sizeof(struct p9_stat);
+	memmove(p, st->name.str, st->name.len);
+	p += st->name.len;
+	memmove(p, st->uid.str, st->uid.len);
+	p += st->uid.len;
+	memmove(p, st->gid.str, st->gid.len);
+	p += st->gid.len;
+	memmove(p, st->muid.str, st->muid.len);
+	p += st->muid.len;
+
+	if (dotu) {
+		memmove(p, st->extension.str, st->extension.len);
+		p += st->extension.len;
+	}
+
+	return ret;
+}
+
+static struct p9_fid *p9_fid_create(struct p9_client *clnt)
+{
+	int err;
+	struct p9_fid *fid;
+
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
+	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
+	if (!fid)
+		return ERR_PTR(-ENOMEM);
+
+	fid->fid = p9_idpool_get(clnt->fidpool);
+	if (fid->fid < 0) {
+		err = -ENOSPC;
+		goto error;
+	}
+
+	memset(&fid->qid, 0, sizeof(struct p9_qid));
+	fid->mode = -1;
+	fid->rdir_fpos = 0;
+	fid->rdir_pos = 0;
+	fid->rdir_fcall = NULL;
+	fid->uid = current->fsuid;
+	fid->clnt = clnt;
+	fid->aux = NULL;
+
+	spin_lock(&clnt->lock);
+	list_add(&fid->flist, &clnt->fidlist);
+	spin_unlock(&clnt->lock);
+
+	return fid;
+
+error:
+	kfree(fid);
+	return ERR_PTR(err);
+}
+
+static void p9_fid_destroy(struct p9_fid *fid)
+{
+	struct p9_client *clnt;
+
+	P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
+	clnt = fid->clnt;
+	p9_idpool_put(fid->fid, clnt->fidpool);
+	spin_lock(&clnt->lock);
+	list_del(&fid->flist);
+	spin_unlock(&clnt->lock);
+	kfree(fid->rdir_fcall);
+	kfree(fid);
+}
diff --git a/net/9p/conv.c b/net/9p/conv.c
new file mode 100644
index 000000000000..37451178e761
--- /dev/null
+++ b/net/9p/conv.c
@@ -0,0 +1,903 @@
+/*
+ * net/9p/conv.c
+ *
+ * 9P protocol conversion functions
+ *
+ *  Copyright (C) 2004, 2005 by Latchesar Ionkov <lucho@ionkov.net>
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/idr.h>
+#include <linux/uaccess.h>
+#include <net/9p/9p.h>
+
+/*
+ * Buffer to help with string parsing
+ */
+struct cbuf {
+	unsigned char *sp;
+	unsigned char *p;
+	unsigned char *ep;
+};
+
+static inline void buf_init(struct cbuf *buf, void *data, int datalen)
+{
+	buf->sp = buf->p = data;
+	buf->ep = data + datalen;
+}
+
+static inline int buf_check_overflow(struct cbuf *buf)
+{
+	return buf->p > buf->ep;
+}
+
+static int buf_check_size(struct cbuf *buf, int len)
+{
+	if (buf->p + len > buf->ep) {
+		if (buf->p < buf->ep) {
+			P9_EPRINTK(KERN_ERR,
+				"buffer overflow: want %d has %d\n", len,
+				(int)(buf->ep - buf->p));
+			dump_stack();
+			buf->p = buf->ep + 1;
+		}
+
+		return 0;
+	}
+
+	return 1;
+}
+
+static void *buf_alloc(struct cbuf *buf, int len)
+{
+	void *ret = NULL;
+
+	if (buf_check_size(buf, len)) {
+		ret = buf->p;
+		buf->p += len;
+	}
+
+	return ret;
+}
+
+static void buf_put_int8(struct cbuf *buf, u8 val)
+{
+	if (buf_check_size(buf, 1)) {
+		buf->p[0] = val;
+		buf->p++;
+	}
+}
+
+static void buf_put_int16(struct cbuf *buf, u16 val)
+{
+	if (buf_check_size(buf, 2)) {
+		*(__le16 *) buf->p = cpu_to_le16(val);
+		buf->p += 2;
+	}
+}
+
+static void buf_put_int32(struct cbuf *buf, u32 val)
+{
+	if (buf_check_size(buf, 4)) {
+		*(__le32 *)buf->p = cpu_to_le32(val);
+		buf->p += 4;
+	}
+}
+
+static void buf_put_int64(struct cbuf *buf, u64 val)
+{
+	if (buf_check_size(buf, 8)) {
+		*(__le64 *)buf->p = cpu_to_le64(val);
+		buf->p += 8;
+	}
+}
+
+static char *buf_put_stringn(struct cbuf *buf, const char *s, u16 slen)
+{
+	char *ret;
+
+	ret = NULL;
+	if (buf_check_size(buf, slen + 2)) {
+		buf_put_int16(buf, slen);
+		ret = buf->p;
+		memcpy(buf->p, s, slen);
+		buf->p += slen;
+	}
+
+	return ret;
+}
+
+static inline void buf_put_string(struct cbuf *buf, const char *s)
+{
+	buf_put_stringn(buf, s, strlen(s));
+}
+
+static u8 buf_get_int8(struct cbuf *buf)
+{
+	u8 ret = 0;
+
+	if (buf_check_size(buf, 1)) {
+		ret = buf->p[0];
+		buf->p++;
+	}
+
+	return ret;
+}
+
+static u16 buf_get_int16(struct cbuf *buf)
+{
+	u16 ret = 0;
+
+	if (buf_check_size(buf, 2)) {
+		ret = le16_to_cpu(*(__le16 *)buf->p);
+		buf->p += 2;
+	}
+
+	return ret;
+}
+
+static u32 buf_get_int32(struct cbuf *buf)
+{
+	u32 ret = 0;
+
+	if (buf_check_size(buf, 4)) {
+		ret = le32_to_cpu(*(__le32 *)buf->p);
+		buf->p += 4;
+	}
+
+	return ret;
+}
+
+static u64 buf_get_int64(struct cbuf *buf)
+{
+	u64 ret = 0;
+
+	if (buf_check_size(buf, 8)) {
+		ret = le64_to_cpu(*(__le64 *)buf->p);
+		buf->p += 8;
+	}
+
+	return ret;
+}
+
+static void buf_get_str(struct cbuf *buf, struct p9_str *vstr)
+{
+	vstr->len = buf_get_int16(buf);
+	if (!buf_check_overflow(buf) && buf_check_size(buf, vstr->len)) {
+		vstr->str = buf->p;
+		buf->p += vstr->len;
+	} else {
+		vstr->len = 0;
+		vstr->str = NULL;
+	}
+}
+
+static void buf_get_qid(struct cbuf *bufp, struct p9_qid *qid)
+{
+	qid->type = buf_get_int8(bufp);
+	qid->version = buf_get_int32(bufp);
+	qid->path = buf_get_int64(bufp);
+}
+
+/**
+ * p9_size_wstat - calculate the size of a variable length stat struct
+ * @stat: metadata (stat) structure
+ * @dotu: non-zero if 9P2000.u
+ *
+ */
+
+static int p9_size_wstat(struct p9_wstat *wstat, int dotu)
+{
+	int size = 0;
+
+	if (wstat == NULL) {
+		P9_EPRINTK(KERN_ERR, "p9_size_stat: got a NULL stat pointer\n");
+		return 0;
+	}
+
+	size =			/* 2 + *//* size[2] */
+	    2 +			/* type[2] */
+	    4 +			/* dev[4] */
+	    1 +			/* qid.type[1] */
+	    4 +			/* qid.vers[4] */
+	    8 +			/* qid.path[8] */
+	    4 +			/* mode[4] */
+	    4 +			/* atime[4] */
+	    4 +			/* mtime[4] */
+	    8 +			/* length[8] */
+	    8;			/* minimum sum of string lengths */
+
+	if (wstat->name)
+		size += strlen(wstat->name);
+	if (wstat->uid)
+		size += strlen(wstat->uid);
+	if (wstat->gid)
+		size += strlen(wstat->gid);
+	if (wstat->muid)
+		size += strlen(wstat->muid);
+
+	if (dotu) {
+		size += 4 +	/* n_uid[4] */
+		    4 +		/* n_gid[4] */
+		    4 +		/* n_muid[4] */
+		    2;		/* string length of extension[4] */
+		if (wstat->extension)
+			size += strlen(wstat->extension);
+	}
+
+	return size;
+}
+
+/**
+ * buf_get_stat - safely decode a recieved metadata (stat) structure
+ * @bufp: buffer to deserialize
+ * @stat: metadata (stat) structure
+ * @dotu: non-zero if 9P2000.u
+ *
+ */
+
+static void
+buf_get_stat(struct cbuf *bufp, struct p9_stat *stat, int dotu)
+{
+	stat->size = buf_get_int16(bufp);
+	stat->type = buf_get_int16(bufp);
+	stat->dev = buf_get_int32(bufp);
+	stat->qid.type = buf_get_int8(bufp);
+	stat->qid.version = buf_get_int32(bufp);
+	stat->qid.path = buf_get_int64(bufp);
+	stat->mode = buf_get_int32(bufp);
+	stat->atime = buf_get_int32(bufp);
+	stat->mtime = buf_get_int32(bufp);
+	stat->length = buf_get_int64(bufp);
+	buf_get_str(bufp, &stat->name);
+	buf_get_str(bufp, &stat->uid);
+	buf_get_str(bufp, &stat->gid);
+	buf_get_str(bufp, &stat->muid);
+
+	if (dotu) {
+		buf_get_str(bufp, &stat->extension);
+		stat->n_uid = buf_get_int32(bufp);
+		stat->n_gid = buf_get_int32(bufp);
+		stat->n_muid = buf_get_int32(bufp);
+	}
+}
+
+/**
+ * p9_deserialize_stat - decode a received metadata structure
+ * @buf: buffer to deserialize
+ * @buflen: length of received buffer
+ * @stat: metadata structure to decode into
+ * @dotu: non-zero if 9P2000.u
+ *
+ * Note: stat will point to the buf region.
+ */
+
+int
+p9_deserialize_stat(void *buf, u32 buflen, struct p9_stat *stat,
+		int dotu)
+{
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+	unsigned char *p;
+
+	buf_init(bufp, buf, buflen);
+	p = bufp->p;
+	buf_get_stat(bufp, stat, dotu);
+
+	if (buf_check_overflow(bufp))
+		return 0;
+	else
+		return bufp->p - p;
+}
+EXPORT_SYMBOL(p9_deserialize_stat);
+
+/**
+ * deserialize_fcall - unmarshal a response
+ * @buf: recieved buffer
+ * @buflen: length of received buffer
+ * @rcall: fcall structure to populate
+ * @rcalllen: length of fcall structure to populate
+ * @dotu: non-zero if 9P2000.u
+ *
+ */
+
+int
+p9_deserialize_fcall(void *buf, u32 buflen, struct p9_fcall *rcall,
+		       int dotu)
+{
+
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+	int i = 0;
+
+	buf_init(bufp, buf, buflen);
+
+	rcall->size = buf_get_int32(bufp);
+	rcall->id = buf_get_int8(bufp);
+	rcall->tag = buf_get_int16(bufp);
+
+	P9_DPRINTK(P9_DEBUG_CONV, "size %d id %d tag %d\n", rcall->size,
+							rcall->id, rcall->tag);
+
+	switch (rcall->id) {
+	default:
+		P9_EPRINTK(KERN_ERR, "unknown message type: %d\n", rcall->id);
+		return -EPROTO;
+	case P9_RVERSION:
+		rcall->params.rversion.msize = buf_get_int32(bufp);
+		buf_get_str(bufp, &rcall->params.rversion.version);
+		break;
+	case P9_RFLUSH:
+		break;
+	case P9_RATTACH:
+		rcall->params.rattach.qid.type = buf_get_int8(bufp);
+		rcall->params.rattach.qid.version = buf_get_int32(bufp);
+		rcall->params.rattach.qid.path = buf_get_int64(bufp);
+		break;
+	case P9_RWALK:
+		rcall->params.rwalk.nwqid = buf_get_int16(bufp);
+		if (rcall->params.rwalk.nwqid > P9_MAXWELEM) {
+			P9_EPRINTK(KERN_ERR,
+					"Rwalk with more than %d qids: %d\n",
+					P9_MAXWELEM, rcall->params.rwalk.nwqid);
+			return -EPROTO;
+		}
+
+		for (i = 0; i < rcall->params.rwalk.nwqid; i++)
+			buf_get_qid(bufp, &rcall->params.rwalk.wqids[i]);
+		break;
+	case P9_ROPEN:
+		buf_get_qid(bufp, &rcall->params.ropen.qid);
+		rcall->params.ropen.iounit = buf_get_int32(bufp);
+		break;
+	case P9_RCREATE:
+		buf_get_qid(bufp, &rcall->params.rcreate.qid);
+		rcall->params.rcreate.iounit = buf_get_int32(bufp);
+		break;
+	case P9_RREAD:
+		rcall->params.rread.count = buf_get_int32(bufp);
+		rcall->params.rread.data = bufp->p;
+		buf_check_size(bufp, rcall->params.rread.count);
+		break;
+	case P9_RWRITE:
+		rcall->params.rwrite.count = buf_get_int32(bufp);
+		break;
+	case P9_RCLUNK:
+		break;
+	case P9_RREMOVE:
+		break;
+	case P9_RSTAT:
+		buf_get_int16(bufp);
+		buf_get_stat(bufp, &rcall->params.rstat.stat, dotu);
+		break;
+	case P9_RWSTAT:
+		break;
+	case P9_RERROR:
+		buf_get_str(bufp, &rcall->params.rerror.error);
+		if (dotu)
+			rcall->params.rerror.errno = buf_get_int16(bufp);
+		break;
+	}
+
+	if (buf_check_overflow(bufp)) {
+		P9_DPRINTK(P9_DEBUG_ERROR, "buffer overflow\n");
+		return -EIO;
+	}
+
+	return bufp->p - bufp->sp;
+}
+EXPORT_SYMBOL(p9_deserialize_fcall);
+
+static inline void p9_put_int8(struct cbuf *bufp, u8 val, u8 * p)
+{
+	*p = val;
+	buf_put_int8(bufp, val);
+}
+
+static inline void p9_put_int16(struct cbuf *bufp, u16 val, u16 * p)
+{
+	*p = val;
+	buf_put_int16(bufp, val);
+}
+
+static inline void p9_put_int32(struct cbuf *bufp, u32 val, u32 * p)
+{
+	*p = val;
+	buf_put_int32(bufp, val);
+}
+
+static inline void p9_put_int64(struct cbuf *bufp, u64 val, u64 * p)
+{
+	*p = val;
+	buf_put_int64(bufp, val);
+}
+
+static void
+p9_put_str(struct cbuf *bufp, char *data, struct p9_str *str)
+{
+	int len;
+	char *s;
+
+	if (data)
+		len = strlen(data);
+	else
+		len = 0;
+
+	s = buf_put_stringn(bufp, data, len);
+	if (str) {
+		str->len = len;
+		str->str = s;
+	}
+}
+
+static int
+p9_put_data(struct cbuf *bufp, const char *data, int count,
+		   unsigned char **pdata)
+{
+	*pdata = buf_alloc(bufp, count);
+	memmove(*pdata, data, count);
+	return count;
+}
+
+static int
+p9_put_user_data(struct cbuf *bufp, const char __user *data, int count,
+		   unsigned char **pdata)
+{
+	*pdata = buf_alloc(bufp, count);
+	return copy_from_user(*pdata, data, count);
+}
+
+static void
+p9_put_wstat(struct cbuf *bufp, struct p9_wstat *wstat,
+	       struct p9_stat *stat, int statsz, int dotu)
+{
+	p9_put_int16(bufp, statsz, &stat->size);
+	p9_put_int16(bufp, wstat->type, &stat->type);
+	p9_put_int32(bufp, wstat->dev, &stat->dev);
+	p9_put_int8(bufp, wstat->qid.type, &stat->qid.type);
+	p9_put_int32(bufp, wstat->qid.version, &stat->qid.version);
+	p9_put_int64(bufp, wstat->qid.path, &stat->qid.path);
+	p9_put_int32(bufp, wstat->mode, &stat->mode);
+	p9_put_int32(bufp, wstat->atime, &stat->atime);
+	p9_put_int32(bufp, wstat->mtime, &stat->mtime);
+	p9_put_int64(bufp, wstat->length, &stat->length);
+
+	p9_put_str(bufp, wstat->name, &stat->name);
+	p9_put_str(bufp, wstat->uid, &stat->uid);
+	p9_put_str(bufp, wstat->gid, &stat->gid);
+	p9_put_str(bufp, wstat->muid, &stat->muid);
+
+	if (dotu) {
+		p9_put_str(bufp, wstat->extension, &stat->extension);
+		p9_put_int32(bufp, wstat->n_uid, &stat->n_uid);
+		p9_put_int32(bufp, wstat->n_gid, &stat->n_gid);
+		p9_put_int32(bufp, wstat->n_muid, &stat->n_muid);
+	}
+}
+
+static struct p9_fcall *
+p9_create_common(struct cbuf *bufp, u32 size, u8 id)
+{
+	struct p9_fcall *fc;
+
+	size += 4 + 1 + 2;	/* size[4] id[1] tag[2] */
+	fc = kmalloc(sizeof(struct p9_fcall) + size, GFP_KERNEL);
+	if (!fc)
+		return ERR_PTR(-ENOMEM);
+
+	fc->sdata = (char *)fc + sizeof(*fc);
+
+	buf_init(bufp, (char *)fc->sdata, size);
+	p9_put_int32(bufp, size, &fc->size);
+	p9_put_int8(bufp, id, &fc->id);
+	p9_put_int16(bufp, P9_NOTAG, &fc->tag);
+
+	return fc;
+}
+
+void p9_set_tag(struct p9_fcall *fc, u16 tag)
+{
+	fc->tag = tag;
+	*(__le16 *) (fc->sdata + 5) = cpu_to_le16(tag);
+}
+EXPORT_SYMBOL(p9_set_tag);
+
+struct p9_fcall *p9_create_tversion(u32 msize, char *version)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 4 + 2 + strlen(version);	/* msize[4] version[s] */
+	fc = p9_create_common(bufp, size, P9_TVERSION);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, msize, &fc->params.tversion.msize);
+	p9_put_str(bufp, version, &fc->params.tversion.version);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tversion);
+
+struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	/* afid[4] uname[s] aname[s] */
+	size = 4 + 2 + strlen(uname) + 2 + strlen(aname);
+	fc = p9_create_common(bufp, size, P9_TAUTH);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, afid, &fc->params.tauth.afid);
+	p9_put_str(bufp, uname, &fc->params.tauth.uname);
+	p9_put_str(bufp, aname, &fc->params.tauth.aname);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tauth);
+
+struct p9_fcall *
+p9_create_tattach(u32 fid, u32 afid, char *uname, char *aname)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	/* fid[4] afid[4] uname[s] aname[s] */
+	size = 4 + 4 + 2 + strlen(uname) + 2 + strlen(aname);
+	fc = p9_create_common(bufp, size, P9_TATTACH);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.tattach.fid);
+	p9_put_int32(bufp, afid, &fc->params.tattach.afid);
+	p9_put_str(bufp, uname, &fc->params.tattach.uname);
+	p9_put_str(bufp, aname, &fc->params.tattach.aname);
+
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tattach);
+
+struct p9_fcall *p9_create_tflush(u16 oldtag)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 2;		/* oldtag[2] */
+	fc = p9_create_common(bufp, size, P9_TFLUSH);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int16(bufp, oldtag, &fc->params.tflush.oldtag);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tflush);
+
+struct p9_fcall *p9_create_twalk(u32 fid, u32 newfid, u16 nwname,
+				     char **wnames)
+{
+	int i, size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	if (nwname > P9_MAXWELEM) {
+		P9_DPRINTK(P9_DEBUG_ERROR, "nwname > %d\n", P9_MAXWELEM);
+		return NULL;
+	}
+
+	size = 4 + 4 + 2;	/* fid[4] newfid[4] nwname[2] ... */
+	for (i = 0; i < nwname; i++) {
+		size += 2 + strlen(wnames[i]);	/* wname[s] */
+	}
+
+	fc = p9_create_common(bufp, size, P9_TWALK);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.twalk.fid);
+	p9_put_int32(bufp, newfid, &fc->params.twalk.newfid);
+	p9_put_int16(bufp, nwname, &fc->params.twalk.nwname);
+	for (i = 0; i < nwname; i++) {
+		p9_put_str(bufp, wnames[i], &fc->params.twalk.wnames[i]);
+	}
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_twalk);
+
+struct p9_fcall *p9_create_topen(u32 fid, u8 mode)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 4 + 1;		/* fid[4] mode[1] */
+	fc = p9_create_common(bufp, size, P9_TOPEN);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.topen.fid);
+	p9_put_int8(bufp, mode, &fc->params.topen.mode);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_topen);
+
+struct p9_fcall *p9_create_tcreate(u32 fid, char *name, u32 perm, u8 mode,
+	char *extension, int dotu)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	/* fid[4] name[s] perm[4] mode[1] */
+	size = 4 + 2 + strlen(name) + 4 + 1;
+	if (dotu) {
+		size += 2 +			/* extension[s] */
+		    (extension == NULL ? 0 : strlen(extension));
+	}
+
+	fc = p9_create_common(bufp, size, P9_TCREATE);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.tcreate.fid);
+	p9_put_str(bufp, name, &fc->params.tcreate.name);
+	p9_put_int32(bufp, perm, &fc->params.tcreate.perm);
+	p9_put_int8(bufp, mode, &fc->params.tcreate.mode);
+	if (dotu)
+		p9_put_str(bufp, extension, &fc->params.tcreate.extension);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tcreate);
+
+struct p9_fcall *p9_create_tread(u32 fid, u64 offset, u32 count)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 4 + 8 + 4;	/* fid[4] offset[8] count[4] */
+	fc = p9_create_common(bufp, size, P9_TREAD);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.tread.fid);
+	p9_put_int64(bufp, offset, &fc->params.tread.offset);
+	p9_put_int32(bufp, count, &fc->params.tread.count);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tread);
+
+struct p9_fcall *p9_create_twrite(u32 fid, u64 offset, u32 count,
+				      const char *data)
+{
+	int size, err;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	/* fid[4] offset[8] count[4] data[count] */
+	size = 4 + 8 + 4 + count;
+	fc = p9_create_common(bufp, size, P9_TWRITE);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.twrite.fid);
+	p9_put_int64(bufp, offset, &fc->params.twrite.offset);
+	p9_put_int32(bufp, count, &fc->params.twrite.count);
+	err = p9_put_data(bufp, data, count, &fc->params.twrite.data);
+	if (err) {
+		kfree(fc);
+		fc = ERR_PTR(err);
+	}
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_twrite);
+
+struct p9_fcall *p9_create_twrite_u(u32 fid, u64 offset, u32 count,
+				      const char __user *data)
+{
+	int size, err;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	/* fid[4] offset[8] count[4] data[count] */
+	size = 4 + 8 + 4 + count;
+	fc = p9_create_common(bufp, size, P9_TWRITE);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.twrite.fid);
+	p9_put_int64(bufp, offset, &fc->params.twrite.offset);
+	p9_put_int32(bufp, count, &fc->params.twrite.count);
+	err = p9_put_user_data(bufp, data, count, &fc->params.twrite.data);
+	if (err) {
+		kfree(fc);
+		fc = ERR_PTR(err);
+	}
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_twrite_u);
+
+struct p9_fcall *p9_create_tclunk(u32 fid)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 4;		/* fid[4] */
+	fc = p9_create_common(bufp, size, P9_TCLUNK);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.tclunk.fid);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tclunk);
+
+struct p9_fcall *p9_create_tremove(u32 fid)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 4;		/* fid[4] */
+	fc = p9_create_common(bufp, size, P9_TREMOVE);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.tremove.fid);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tremove);
+
+struct p9_fcall *p9_create_tstat(u32 fid)
+{
+	int size;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	size = 4;		/* fid[4] */
+	fc = p9_create_common(bufp, size, P9_TSTAT);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.tstat.fid);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_tstat);
+
+struct p9_fcall *p9_create_twstat(u32 fid, struct p9_wstat *wstat,
+				      int dotu)
+{
+	int size, statsz;
+	struct p9_fcall *fc;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	statsz = p9_size_wstat(wstat, dotu);
+	size = 4 + 2 + 2 + statsz;	/* fid[4] stat[n] */
+	fc = p9_create_common(bufp, size, P9_TWSTAT);
+	if (IS_ERR(fc))
+		goto error;
+
+	p9_put_int32(bufp, fid, &fc->params.twstat.fid);
+	buf_put_int16(bufp, statsz + 2);
+	p9_put_wstat(bufp, wstat, &fc->params.twstat.stat, statsz, dotu);
+
+	if (buf_check_overflow(bufp)) {
+		kfree(fc);
+		fc = ERR_PTR(-ENOMEM);
+	}
+error:
+	return fc;
+}
+EXPORT_SYMBOL(p9_create_twstat);
diff --git a/net/9p/error.c b/net/9p/error.c
new file mode 100644
index 000000000000..ab2458b6c903
--- /dev/null
+++ b/net/9p/error.c
@@ -0,0 +1,240 @@
+/*
+ * linux/fs/9p/error.c
+ *
+ * Error string handling
+ *
+ * Plan 9 uses error strings, Unix uses error numbers.  These functions
+ * try to help manage that and provide for dynamically adding error
+ * mappings.
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/jhash.h>
+#include <linux/errno.h>
+#include <net/9p/9p.h>
+
+struct errormap {
+	char *name;
+	int val;
+
+	int namelen;
+	struct hlist_node list;
+};
+
+#define ERRHASHSZ		32
+static struct hlist_head hash_errmap[ERRHASHSZ];
+
+/* FixMe - reduce to a reasonable size */
+static struct errormap errmap[] = {
+	{"Operation not permitted", EPERM},
+	{"wstat prohibited", EPERM},
+	{"No such file or directory", ENOENT},
+	{"directory entry not found", ENOENT},
+	{"file not found", ENOENT},
+	{"Interrupted system call", EINTR},
+	{"Input/output error", EIO},
+	{"No such device or address", ENXIO},
+	{"Argument list too long", E2BIG},
+	{"Bad file descriptor", EBADF},
+	{"Resource temporarily unavailable", EAGAIN},
+	{"Cannot allocate memory", ENOMEM},
+	{"Permission denied", EACCES},
+	{"Bad address", EFAULT},
+	{"Block device required", ENOTBLK},
+	{"Device or resource busy", EBUSY},
+	{"File exists", EEXIST},
+	{"Invalid cross-device link", EXDEV},
+	{"No such device", ENODEV},
+	{"Not a directory", ENOTDIR},
+	{"Is a directory", EISDIR},
+	{"Invalid argument", EINVAL},
+	{"Too many open files in system", ENFILE},
+	{"Too many open files", EMFILE},
+	{"Text file busy", ETXTBSY},
+	{"File too large", EFBIG},
+	{"No space left on device", ENOSPC},
+	{"Illegal seek", ESPIPE},
+	{"Read-only file system", EROFS},
+	{"Too many links", EMLINK},
+	{"Broken pipe", EPIPE},
+	{"Numerical argument out of domain", EDOM},
+	{"Numerical result out of range", ERANGE},
+	{"Resource deadlock avoided", EDEADLK},
+	{"File name too long", ENAMETOOLONG},
+	{"No locks available", ENOLCK},
+	{"Function not implemented", ENOSYS},
+	{"Directory not empty", ENOTEMPTY},
+	{"Too many levels of symbolic links", ELOOP},
+	{"No message of desired type", ENOMSG},
+	{"Identifier removed", EIDRM},
+	{"No data available", ENODATA},
+	{"Machine is not on the network", ENONET},
+	{"Package not installed", ENOPKG},
+	{"Object is remote", EREMOTE},
+	{"Link has been severed", ENOLINK},
+	{"Communication error on send", ECOMM},
+	{"Protocol error", EPROTO},
+	{"Bad message", EBADMSG},
+	{"File descriptor in bad state", EBADFD},
+	{"Streams pipe error", ESTRPIPE},
+	{"Too many users", EUSERS},
+	{"Socket operation on non-socket", ENOTSOCK},
+	{"Message too long", EMSGSIZE},
+	{"Protocol not available", ENOPROTOOPT},
+	{"Protocol not supported", EPROTONOSUPPORT},
+	{"Socket type not supported", ESOCKTNOSUPPORT},
+	{"Operation not supported", EOPNOTSUPP},
+	{"Protocol family not supported", EPFNOSUPPORT},
+	{"Network is down", ENETDOWN},
+	{"Network is unreachable", ENETUNREACH},
+	{"Network dropped connection on reset", ENETRESET},
+	{"Software caused connection abort", ECONNABORTED},
+	{"Connection reset by peer", ECONNRESET},
+	{"No buffer space available", ENOBUFS},
+	{"Transport endpoint is already connected", EISCONN},
+	{"Transport endpoint is not connected", ENOTCONN},
+	{"Cannot send after transport endpoint shutdown", ESHUTDOWN},
+	{"Connection timed out", ETIMEDOUT},
+	{"Connection refused", ECONNREFUSED},
+	{"Host is down", EHOSTDOWN},
+	{"No route to host", EHOSTUNREACH},
+	{"Operation already in progress", EALREADY},
+	{"Operation now in progress", EINPROGRESS},
+	{"Is a named type file", EISNAM},
+	{"Remote I/O error", EREMOTEIO},
+	{"Disk quota exceeded", EDQUOT},
+/* errors from fossil, vacfs, and u9fs */
+	{"fid unknown or out of range", EBADF},
+	{"permission denied", EACCES},
+	{"file does not exist", ENOENT},
+	{"authentication failed", ECONNREFUSED},
+	{"bad offset in directory read", ESPIPE},
+	{"bad use of fid", EBADF},
+	{"wstat can't convert between files and directories", EPERM},
+	{"directory is not empty", ENOTEMPTY},
+	{"file exists", EEXIST},
+	{"file already exists", EEXIST},
+	{"file or directory already exists", EEXIST},
+	{"fid already in use", EBADF},
+	{"file in use", ETXTBSY},
+	{"i/o error", EIO},
+	{"file already open for I/O", ETXTBSY},
+	{"illegal mode", EINVAL},
+	{"illegal name", ENAMETOOLONG},
+	{"not a directory", ENOTDIR},
+	{"not a member of proposed group", EPERM},
+	{"not owner", EACCES},
+	{"only owner can change group in wstat", EACCES},
+	{"read only file system", EROFS},
+	{"no access to special file", EPERM},
+	{"i/o count too large", EIO},
+	{"unknown group", EINVAL},
+	{"unknown user", EINVAL},
+	{"bogus wstat buffer", EPROTO},
+	{"exclusive use file already open", EAGAIN},
+	{"corrupted directory entry", EIO},
+	{"corrupted file entry", EIO},
+	{"corrupted block label", EIO},
+	{"corrupted meta data", EIO},
+	{"illegal offset", EINVAL},
+	{"illegal path element", ENOENT},
+	{"root of file system is corrupted", EIO},
+	{"corrupted super block", EIO},
+	{"protocol botch", EPROTO},
+	{"file system is full", ENOSPC},
+	{"file is in use", EAGAIN},
+	{"directory entry is not allocated", ENOENT},
+	{"file is read only", EROFS},
+	{"file has been removed", EIDRM},
+	{"only support truncation to zero length", EPERM},
+	{"cannot remove root", EPERM},
+	{"file too big", EFBIG},
+	{"venti i/o error", EIO},
+	/* these are not errors */
+	{"u9fs rhostsauth: no authentication required", 0},
+	{"u9fs authnone: no authentication required", 0},
+	{NULL, -1}
+};
+
+/**
+ * p9_error_init - preload
+ * @errstr: error string
+ *
+ */
+
+int p9_error_init(void)
+{
+	struct errormap *c;
+	int bucket;
+
+	/* initialize hash table */
+	for (bucket = 0; bucket < ERRHASHSZ; bucket++)
+		INIT_HLIST_HEAD(&hash_errmap[bucket]);
+
+	/* load initial error map into hash table */
+	for (c = errmap; c->name != NULL; c++) {
+		c->namelen = strlen(c->name);
+		bucket = jhash(c->name, c->namelen, 0) % ERRHASHSZ;
+		INIT_HLIST_NODE(&c->list);
+		hlist_add_head(&c->list, &hash_errmap[bucket]);
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL(p9_error_init);
+
+/**
+ * errstr2errno - convert error string to error number
+ * @errstr: error string
+ *
+ */
+
+int p9_errstr2errno(char *errstr, int len)
+{
+	int errno;
+	struct hlist_node *p;
+	struct errormap *c;
+	int bucket;
+
+	errno = 0;
+	p = NULL;
+	c = NULL;
+	bucket = jhash(errstr, len, 0) % ERRHASHSZ;
+	hlist_for_each_entry(c, p, &hash_errmap[bucket], list) {
+		if (c->namelen == len && !memcmp(c->name, errstr, len)) {
+			errno = c->val;
+			break;
+		}
+	}
+
+	if (errno == 0) {
+		/* TODO: if error isn't found, add it dynamically */
+		errstr[len] = 0;
+		printk(KERN_ERR "%s: errstr :%s: not found\n", __FUNCTION__,
+		       errstr);
+		errno = 1;
+	}
+
+	return -errno;
+}
+EXPORT_SYMBOL(p9_errstr2errno);
diff --git a/net/9p/fcprint.c b/net/9p/fcprint.c
new file mode 100644
index 000000000000..b1ae8ec57d54
--- /dev/null
+++ b/net/9p/fcprint.c
@@ -0,0 +1,358 @@
+/*
+ *  net/9p/fcprint.c
+ *
+ *  Print 9P call.
+ *
+ *  Copyright (C) 2005 by Latchesar Ionkov <lucho@ionkov.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <net/9p/9p.h>
+
+#ifdef CONFIG_NET_9P_DEBUG
+
+static int
+p9_printqid(char *buf, int buflen, struct p9_qid *q)
+{
+	int n;
+	char b[10];
+
+	n = 0;
+	if (q->type & P9_QTDIR)
+		b[n++] = 'd';
+	if (q->type & P9_QTAPPEND)
+		b[n++] = 'a';
+	if (q->type & P9_QTAUTH)
+		b[n++] = 'A';
+	if (q->type & P9_QTEXCL)
+		b[n++] = 'l';
+	if (q->type & P9_QTTMP)
+		b[n++] = 't';
+	if (q->type & P9_QTSYMLINK)
+		b[n++] = 'L';
+	b[n] = '\0';
+
+	return scnprintf(buf, buflen, "(%.16llx %x %s)",
+					(long long int) q->path, q->version, b);
+}
+
+static int
+p9_printperm(char *buf, int buflen, int perm)
+{
+	int n;
+	char b[15];
+
+	n = 0;
+	if (perm & P9_DMDIR)
+		b[n++] = 'd';
+	if (perm & P9_DMAPPEND)
+		b[n++] = 'a';
+	if (perm & P9_DMAUTH)
+		b[n++] = 'A';
+	if (perm & P9_DMEXCL)
+		b[n++] = 'l';
+	if (perm & P9_DMTMP)
+		b[n++] = 't';
+	if (perm & P9_DMDEVICE)
+		b[n++] = 'D';
+	if (perm & P9_DMSOCKET)
+		b[n++] = 'S';
+	if (perm & P9_DMNAMEDPIPE)
+		b[n++] = 'P';
+	if (perm & P9_DMSYMLINK)
+		b[n++] = 'L';
+	b[n] = '\0';
+
+	return scnprintf(buf, buflen, "%s%03o", b, perm&077);
+}
+
+static int
+p9_printstat(char *buf, int buflen, struct p9_stat *st, int extended)
+{
+	int n;
+
+	n = scnprintf(buf, buflen, "'%.*s' '%.*s'", st->name.len,
+		st->name.str, st->uid.len, st->uid.str);
+	if (extended)
+		n += scnprintf(buf+n, buflen-n, "(%d)", st->n_uid);
+
+	n += scnprintf(buf+n, buflen-n, " '%.*s'", st->gid.len, st->gid.str);
+	if (extended)
+		n += scnprintf(buf+n, buflen-n, "(%d)", st->n_gid);
+
+	n += scnprintf(buf+n, buflen-n, " '%.*s'", st->muid.len, st->muid.str);
+	if (extended)
+		n += scnprintf(buf+n, buflen-n, "(%d)", st->n_muid);
+
+	n += scnprintf(buf+n, buflen-n, " q ");
+	n += p9_printqid(buf+n, buflen-n, &st->qid);
+	n += scnprintf(buf+n, buflen-n, " m ");
+	n += p9_printperm(buf+n, buflen-n, st->mode);
+	n += scnprintf(buf+n, buflen-n, " at %d mt %d l %lld",
+		st->atime, st->mtime, (long long int) st->length);
+
+	if (extended)
+		n += scnprintf(buf+n, buflen-n, " ext '%.*s'",
+			st->extension.len, st->extension.str);
+
+	return n;
+}
+
+static int
+p9_dumpdata(char *buf, int buflen, u8 *data, int datalen)
+{
+	int i, n;
+
+	i = n = 0;
+	while (i < datalen) {
+		n += scnprintf(buf + n, buflen - n, "%02x", data[i]);
+		if (i%4 == 3)
+			n += scnprintf(buf + n, buflen - n, " ");
+		if (i%32 == 31)
+			n += scnprintf(buf + n, buflen - n, "\n");
+
+		i++;
+	}
+	n += scnprintf(buf + n, buflen - n, "\n");
+
+	return n;
+}
+
+static int
+p9_printdata(char *buf, int buflen, u8 *data, int datalen)
+{
+	return p9_dumpdata(buf, buflen, data, datalen < 16?datalen:16);
+}
+
+int
+p9_printfcall(char *buf, int buflen, struct p9_fcall *fc, int extended)
+{
+	int i, ret, type, tag;
+
+	if (!fc)
+		return scnprintf(buf, buflen, "<NULL>");
+
+	type = fc->id;
+	tag = fc->tag;
+
+	ret = 0;
+	switch (type) {
+	case P9_TVERSION:
+		ret += scnprintf(buf+ret, buflen-ret,
+				"Tversion tag %u msize %u version '%.*s'", tag,
+				fc->params.tversion.msize,
+				fc->params.tversion.version.len,
+				fc->params.tversion.version.str);
+		break;
+
+	case P9_RVERSION:
+		ret += scnprintf(buf+ret, buflen-ret,
+				"Rversion tag %u msize %u version '%.*s'", tag,
+				fc->params.rversion.msize,
+				fc->params.rversion.version.len,
+				fc->params.rversion.version.str);
+		break;
+
+	case P9_TAUTH:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Tauth tag %u afid %d uname '%.*s' aname '%.*s'", tag,
+			fc->params.tauth.afid, fc->params.tauth.uname.len,
+			fc->params.tauth.uname.str, fc->params.tauth.aname.len,
+			fc->params.tauth.aname.str);
+		break;
+
+	case P9_RAUTH:
+		ret += scnprintf(buf+ret, buflen-ret, "Rauth tag %u qid ", tag);
+		p9_printqid(buf+ret, buflen-ret, &fc->params.rauth.qid);
+		break;
+
+	case P9_TATTACH:
+		ret += scnprintf(buf+ret, buflen-ret,
+		 "Tattach tag %u fid %d afid %d uname '%.*s' aname '%.*s'", tag,
+		 fc->params.tattach.fid, fc->params.tattach.afid,
+		 fc->params.tattach.uname.len, fc->params.tattach.uname.str,
+		 fc->params.tattach.aname.len, fc->params.tattach.aname.str);
+		break;
+
+	case P9_RATTACH:
+		ret += scnprintf(buf+ret, buflen-ret, "Rattach tag %u qid ",
+									tag);
+		p9_printqid(buf+ret, buflen-ret, &fc->params.rattach.qid);
+		break;
+
+	case P9_RERROR:
+		ret += scnprintf(buf+ret, buflen-ret,
+				"Rerror tag %u ename '%.*s'", tag,
+				fc->params.rerror.error.len,
+				fc->params.rerror.error.str);
+		if (extended)
+			ret += scnprintf(buf+ret, buflen-ret, " ecode %d\n",
+				fc->params.rerror.errno);
+		break;
+
+	case P9_TFLUSH:
+		ret += scnprintf(buf+ret, buflen-ret, "Tflush tag %u oldtag %u",
+			tag, fc->params.tflush.oldtag);
+		break;
+
+	case P9_RFLUSH:
+		ret += scnprintf(buf+ret, buflen-ret, "Rflush tag %u", tag);
+		break;
+
+	case P9_TWALK:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Twalk tag %u fid %d newfid %d nwname %d", tag,
+			fc->params.twalk.fid, fc->params.twalk.newfid,
+			fc->params.twalk.nwname);
+		for (i = 0; i < fc->params.twalk.nwname; i++)
+			ret += scnprintf(buf+ret, buflen-ret, " '%.*s'",
+				fc->params.twalk.wnames[i].len,
+				fc->params.twalk.wnames[i].str);
+		break;
+
+	case P9_RWALK:
+		ret += scnprintf(buf+ret, buflen-ret, "Rwalk tag %u nwqid %d",
+			tag, fc->params.rwalk.nwqid);
+		for (i = 0; i < fc->params.rwalk.nwqid; i++)
+			ret += p9_printqid(buf+ret, buflen-ret,
+				&fc->params.rwalk.wqids[i]);
+		break;
+
+	case P9_TOPEN:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Topen tag %u fid %d mode %d", tag,
+			fc->params.topen.fid, fc->params.topen.mode);
+		break;
+
+	case P9_ROPEN:
+		ret += scnprintf(buf+ret, buflen-ret, "Ropen tag %u", tag);
+		ret += p9_printqid(buf+ret, buflen-ret, &fc->params.ropen.qid);
+		ret += scnprintf(buf+ret, buflen-ret, " iounit %d",
+			fc->params.ropen.iounit);
+		break;
+
+	case P9_TCREATE:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Tcreate tag %u fid %d name '%.*s' perm ", tag,
+			fc->params.tcreate.fid, fc->params.tcreate.name.len,
+			fc->params.tcreate.name.str);
+
+		ret += p9_printperm(buf+ret, buflen-ret,
+						fc->params.tcreate.perm);
+		ret += scnprintf(buf+ret, buflen-ret, " mode %d",
+			fc->params.tcreate.mode);
+		break;
+
+	case P9_RCREATE:
+		ret += scnprintf(buf+ret, buflen-ret, "Rcreate tag %u", tag);
+		ret += p9_printqid(buf+ret, buflen-ret,
+						&fc->params.rcreate.qid);
+		ret += scnprintf(buf+ret, buflen-ret, " iounit %d",
+			fc->params.rcreate.iounit);
+		break;
+
+	case P9_TREAD:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Tread tag %u fid %d offset %lld count %u", tag,
+			fc->params.tread.fid,
+			(long long int) fc->params.tread.offset,
+			fc->params.tread.count);
+		break;
+
+	case P9_RREAD:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Rread tag %u count %u data ", tag,
+			fc->params.rread.count);
+		ret += p9_printdata(buf+ret, buflen-ret, fc->params.rread.data,
+			fc->params.rread.count);
+		break;
+
+	case P9_TWRITE:
+		ret += scnprintf(buf+ret, buflen-ret,
+			"Twrite tag %u fid %d offset %lld count %u data ",
+			tag, fc->params.twrite.fid,
+			(long long int) fc->params.twrite.offset,
+			fc->params.twrite.count);
+		ret += p9_printdata(buf+ret, buflen-ret, fc->params.twrite.data,
+			fc->params.twrite.count);
+		break;
+
+	case P9_RWRITE:
+		ret += scnprintf(buf+ret, buflen-ret, "Rwrite tag %u count %u",
+			tag, fc->params.rwrite.count);
+		break;
+
+	case P9_TCLUNK:
+		ret += scnprintf(buf+ret, buflen-ret, "Tclunk tag %u fid %d",
+			tag, fc->params.tclunk.fid);
+		break;
+
+	case P9_RCLUNK:
+		ret += scnprintf(buf+ret, buflen-ret, "Rclunk tag %u", tag);
+		break;
+
+	case P9_TREMOVE:
+		ret += scnprintf(buf+ret, buflen-ret, "Tremove tag %u fid %d",
+			tag, fc->params.tremove.fid);
+		break;
+
+	case P9_RREMOVE:
+		ret += scnprintf(buf+ret, buflen-ret, "Rremove tag %u", tag);
+		break;
+
+	case P9_TSTAT:
+		ret += scnprintf(buf+ret, buflen-ret, "Tstat tag %u fid %d",
+			tag, fc->params.tstat.fid);
+		break;
+
+	case P9_RSTAT:
+		ret += scnprintf(buf+ret, buflen-ret, "Rstat tag %u ", tag);
+		ret += p9_printstat(buf+ret, buflen-ret, &fc->params.rstat.stat,
+			extended);
+		break;
+
+	case P9_TWSTAT:
+		ret += scnprintf(buf+ret, buflen-ret, "Twstat tag %u fid %d ",
+			tag, fc->params.twstat.fid);
+		ret += p9_printstat(buf+ret, buflen-ret,
+					&fc->params.twstat.stat, extended);
+		break;
+
+	case P9_RWSTAT:
+		ret += scnprintf(buf+ret, buflen-ret, "Rwstat tag %u", tag);
+		break;
+
+	default:
+		ret += scnprintf(buf+ret, buflen-ret, "unknown type %d", type);
+		break;
+	}
+
+	return ret;
+}
+
+#else
+int
+p9_printfcall(char *buf, int buflen, struct p9_fcall *fc, int extended)
+{
+	return 0;
+}
+EXPORT_SYMBOL(p9_printfcall);
+#endif /* CONFIG_NET_9P_DEBUG */
diff --git a/net/9p/mod.c b/net/9p/mod.c
new file mode 100644
index 000000000000..4f9e1d2ac257
--- /dev/null
+++ b/net/9p/mod.c
@@ -0,0 +1,85 @@
+/*
+ *  net/9p/9p.c
+ *
+ *  9P entry point
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <net/9p/9p.h>
+
+#ifdef CONFIG_NET_9P_DEBUG
+unsigned int p9_debug_level = 0;	/* feature-rific global debug level  */
+EXPORT_SYMBOL(p9_debug_level);
+module_param_named(debug, p9_debug_level, uint, 0);
+MODULE_PARM_DESC(debug, "9P debugging level");
+#endif
+
+extern int p9_mux_global_init(void);
+extern void p9_mux_global_exit(void);
+extern int p9_sysctl_register(void);
+extern void p9_sysctl_unregister(void);
+
+/**
+ * v9fs_init - Initialize module
+ *
+ */
+static int __init init_p9(void)
+{
+	int ret;
+
+	p9_error_init();
+	printk(KERN_INFO "Installing 9P2000 support\n");
+	ret = p9_mux_global_init();
+	if (ret) {
+		printk(KERN_WARNING "9p: starting mux failed\n");
+		return ret;
+	}
+
+	ret = p9_sysctl_register();
+	if (ret) {
+		printk(KERN_WARNING "9p: registering sysctl failed\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+/**
+ * v9fs_init - shutdown module
+ *
+ */
+
+static void __exit exit_p9(void)
+{
+	p9_sysctl_unregister();
+	p9_mux_global_exit();
+}
+
+module_init(init_p9)
+module_exit(exit_p9)
+
+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/net/9p/mux.c b/net/9p/mux.c
new file mode 100644
index 000000000000..c3aa87bc8b97
--- /dev/null
+++ b/net/9p/mux.c
@@ -0,0 +1,1050 @@
+/*
+ * net/9p/mux.c
+ *
+ * Protocol Multiplexer
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/kthread.h>
+#include <linux/idr.h>
+#include <linux/mutex.h>
+#include <net/9p/9p.h>
+#include <net/9p/transport.h>
+#include <net/9p/conn.h>
+
+#define ERREQFLUSH	1
+#define SCHED_TIMEOUT	10
+#define MAXPOLLWADDR	2
+
+enum {
+	Rworksched = 1,		/* read work scheduled or running */
+	Rpending = 2,		/* can read */
+	Wworksched = 4,		/* write work scheduled or running */
+	Wpending = 8,		/* can write */
+};
+
+enum {
+	None,
+	Flushing,
+	Flushed,
+};
+
+struct p9_mux_poll_task;
+
+struct p9_req {
+	spinlock_t lock; /* protect request structure */
+	int tag;
+	struct p9_fcall *tcall;
+	struct p9_fcall *rcall;
+	int err;
+	p9_conn_req_callback cb;
+	void *cba;
+	int flush;
+	struct list_head req_list;
+};
+
+struct p9_conn {
+	spinlock_t lock; /* protect lock structure */
+	struct list_head mux_list;
+	struct p9_mux_poll_task *poll_task;
+	int msize;
+	unsigned char *extended;
+	struct p9_transport *trans;
+	struct p9_idpool *tagpool;
+	int err;
+	wait_queue_head_t equeue;
+	struct list_head req_list;
+	struct list_head unsent_req_list;
+	struct p9_fcall *rcall;
+	int rpos;
+	char *rbuf;
+	int wpos;
+	int wsize;
+	char *wbuf;
+	wait_queue_t poll_wait[MAXPOLLWADDR];
+	wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
+	poll_table pt;
+	struct work_struct rq;
+	struct work_struct wq;
+	unsigned long wsched;
+};
+
+struct p9_mux_poll_task {
+	struct task_struct *task;
+	struct list_head mux_list;
+	int muxnum;
+};
+
+struct p9_mux_rpc {
+	struct p9_conn *m;
+	int err;
+	struct p9_fcall *tcall;
+	struct p9_fcall *rcall;
+	wait_queue_head_t wqueue;
+};
+
+static int p9_poll_proc(void *);
+static void p9_read_work(struct work_struct *work);
+static void p9_write_work(struct work_struct *work);
+static void p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
+			  poll_table * p);
+static u16 p9_mux_get_tag(struct p9_conn *);
+static void p9_mux_put_tag(struct p9_conn *, u16);
+
+static DEFINE_MUTEX(p9_mux_task_lock);
+static struct workqueue_struct *p9_mux_wq;
+
+static int p9_mux_num;
+static int p9_mux_poll_task_num;
+static struct p9_mux_poll_task p9_mux_poll_tasks[100];
+
+int p9_mux_global_init(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
+		p9_mux_poll_tasks[i].task = NULL;
+
+	p9_mux_wq = create_workqueue("v9fs");
+	if (!p9_mux_wq) {
+		printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+void p9_mux_global_exit(void)
+{
+	destroy_workqueue(p9_mux_wq);
+}
+
+/**
+ * p9_mux_calc_poll_procs - calculates the number of polling procs
+ * based on the number of mounted v9fs filesystems.
+ *
+ * The current implementation returns sqrt of the number of mounts.
+ */
+static int p9_mux_calc_poll_procs(int muxnum)
+{
+	int n;
+
+	if (p9_mux_poll_task_num)
+		n = muxnum / p9_mux_poll_task_num +
+		    (muxnum % p9_mux_poll_task_num ? 1 : 0);
+	else
+		n = 1;
+
+	if (n > ARRAY_SIZE(p9_mux_poll_tasks))
+		n = ARRAY_SIZE(p9_mux_poll_tasks);
+
+	return n;
+}
+
+static int p9_mux_poll_start(struct p9_conn *m)
+{
+	int i, n;
+	struct p9_mux_poll_task *vpt, *vptlast;
+	struct task_struct *pproc;
+
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, p9_mux_num,
+		p9_mux_poll_task_num);
+	mutex_lock(&p9_mux_task_lock);
+
+	n = p9_mux_calc_poll_procs(p9_mux_num + 1);
+	if (n > p9_mux_poll_task_num) {
+		for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
+			if (p9_mux_poll_tasks[i].task == NULL) {
+				vpt = &p9_mux_poll_tasks[i];
+				P9_DPRINTK(P9_DEBUG_MUX, "create proc %p\n",
+									vpt);
+				pproc = kthread_create(p9_poll_proc, vpt,
+								"v9fs-poll");
+
+				if (!IS_ERR(pproc)) {
+					vpt->task = pproc;
+					INIT_LIST_HEAD(&vpt->mux_list);
+					vpt->muxnum = 0;
+					p9_mux_poll_task_num++;
+					wake_up_process(vpt->task);
+				}
+				break;
+			}
+		}
+
+		if (i >= ARRAY_SIZE(p9_mux_poll_tasks))
+			P9_DPRINTK(P9_DEBUG_ERROR,
+					"warning: no free poll slots\n");
+	}
+
+	n = (p9_mux_num + 1) / p9_mux_poll_task_num +
+	    ((p9_mux_num + 1) % p9_mux_poll_task_num ? 1 : 0);
+
+	vptlast = NULL;
+	for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
+		vpt = &p9_mux_poll_tasks[i];
+		if (vpt->task != NULL) {
+			vptlast = vpt;
+			if (vpt->muxnum < n) {
+				P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
+				list_add(&m->mux_list, &vpt->mux_list);
+				vpt->muxnum++;
+				m->poll_task = vpt;
+				memset(&m->poll_waddr, 0,
+							sizeof(m->poll_waddr));
+				init_poll_funcptr(&m->pt, p9_pollwait);
+				break;
+			}
+		}
+	}
+
+	if (i >= ARRAY_SIZE(p9_mux_poll_tasks)) {
+		if (vptlast == NULL)
+			return -ENOMEM;
+
+		P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
+		list_add(&m->mux_list, &vptlast->mux_list);
+		vptlast->muxnum++;
+		m->poll_task = vptlast;
+		memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
+		init_poll_funcptr(&m->pt, p9_pollwait);
+	}
+
+	p9_mux_num++;
+	mutex_unlock(&p9_mux_task_lock);
+
+	return 0;
+}
+
+static void p9_mux_poll_stop(struct p9_conn *m)
+{
+	int i;
+	struct p9_mux_poll_task *vpt;
+
+	mutex_lock(&p9_mux_task_lock);
+	vpt = m->poll_task;
+	list_del(&m->mux_list);
+	for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
+		if (m->poll_waddr[i] != NULL) {
+			remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
+			m->poll_waddr[i] = NULL;
+		}
+	}
+	vpt->muxnum--;
+	if (!vpt->muxnum) {
+		P9_DPRINTK(P9_DEBUG_MUX, "destroy proc %p\n", vpt);
+		kthread_stop(vpt->task);
+		vpt->task = NULL;
+		p9_mux_poll_task_num--;
+	}
+	p9_mux_num--;
+	mutex_unlock(&p9_mux_task_lock);
+}
+
+/**
+ * p9_conn_create - allocate and initialize the per-session mux data
+ * Creates the polling task if this is the first session.
+ *
+ * @trans - transport structure
+ * @msize - maximum message size
+ * @extended - pointer to the extended flag
+ */
+struct p9_conn *p9_conn_create(struct p9_transport *trans, int msize,
+				    unsigned char *extended)
+{
+	int i, n;
+	struct p9_conn *m, *mtmp;
+
+	P9_DPRINTK(P9_DEBUG_MUX, "transport %p msize %d\n", trans, msize);
+	m = kmalloc(sizeof(struct p9_conn), GFP_KERNEL);
+	if (!m)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_init(&m->lock);
+	INIT_LIST_HEAD(&m->mux_list);
+	m->msize = msize;
+	m->extended = extended;
+	m->trans = trans;
+	m->tagpool = p9_idpool_create();
+	if (!m->tagpool) {
+		kfree(m);
+		return ERR_PTR(PTR_ERR(m->tagpool));
+	}
+
+	m->err = 0;
+	init_waitqueue_head(&m->equeue);
+	INIT_LIST_HEAD(&m->req_list);
+	INIT_LIST_HEAD(&m->unsent_req_list);
+	m->rcall = NULL;
+	m->rpos = 0;
+	m->rbuf = NULL;
+	m->wpos = m->wsize = 0;
+	m->wbuf = NULL;
+	INIT_WORK(&m->rq, p9_read_work);
+	INIT_WORK(&m->wq, p9_write_work);
+	m->wsched = 0;
+	memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
+	m->poll_task = NULL;
+	n = p9_mux_poll_start(m);
+	if (n)
+		return ERR_PTR(n);
+
+	n = trans->poll(trans, &m->pt);
+	if (n & POLLIN) {
+		P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
+		set_bit(Rpending, &m->wsched);
+	}
+
+	if (n & POLLOUT) {
+		P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
+		set_bit(Wpending, &m->wsched);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
+		if (IS_ERR(m->poll_waddr[i])) {
+			p9_mux_poll_stop(m);
+			mtmp = (void *)m->poll_waddr;	/* the error code */
+			kfree(m);
+			m = mtmp;
+			break;
+		}
+	}
+
+	return m;
+}
+EXPORT_SYMBOL(p9_conn_create);
+
+/**
+ * p9_mux_destroy - cancels all pending requests and frees mux resources
+ */
+void p9_conn_destroy(struct p9_conn *m)
+{
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
+		m->mux_list.prev, m->mux_list.next);
+	p9_conn_cancel(m, -ECONNRESET);
+
+	if (!list_empty(&m->req_list)) {
+		/* wait until all processes waiting on this session exit */
+		P9_DPRINTK(P9_DEBUG_MUX,
+			"mux %p waiting for empty request queue\n", m);
+		wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
+		P9_DPRINTK(P9_DEBUG_MUX, "mux %p request queue empty: %d\n", m,
+			list_empty(&m->req_list));
+	}
+
+	p9_mux_poll_stop(m);
+	m->trans = NULL;
+	p9_idpool_destroy(m->tagpool);
+	kfree(m);
+}
+EXPORT_SYMBOL(p9_conn_destroy);
+
+/**
+ * p9_pollwait - called by files poll operation to add v9fs-poll task
+ * 	to files wait queue
+ */
+static void
+p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
+	      poll_table * p)
+{
+	int i;
+	struct p9_conn *m;
+
+	m = container_of(p, struct p9_conn, pt);
+	for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
+		if (m->poll_waddr[i] == NULL)
+			break;
+
+	if (i >= ARRAY_SIZE(m->poll_waddr)) {
+		P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
+		return;
+	}
+
+	m->poll_waddr[i] = wait_address;
+
+	if (!wait_address) {
+		P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
+		m->poll_waddr[i] = ERR_PTR(-EIO);
+		return;
+	}
+
+	init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
+	add_wait_queue(wait_address, &m->poll_wait[i]);
+}
+
+/**
+ * p9_poll_mux - polls a mux and schedules read or write works if necessary
+ */
+static void p9_poll_mux(struct p9_conn *m)
+{
+	int n;
+
+	if (m->err < 0)
+		return;
+
+	n = m->trans->poll(m->trans, NULL);
+	if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
+		P9_DPRINTK(P9_DEBUG_MUX, "error mux %p err %d\n", m, n);
+		if (n >= 0)
+			n = -ECONNRESET;
+		p9_conn_cancel(m, n);
+	}
+
+	if (n & POLLIN) {
+		set_bit(Rpending, &m->wsched);
+		P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
+		if (!test_and_set_bit(Rworksched, &m->wsched)) {
+			P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
+			queue_work(p9_mux_wq, &m->rq);
+		}
+	}
+
+	if (n & POLLOUT) {
+		set_bit(Wpending, &m->wsched);
+		P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
+		if ((m->wsize || !list_empty(&m->unsent_req_list))
+		    && !test_and_set_bit(Wworksched, &m->wsched)) {
+			P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
+			queue_work(p9_mux_wq, &m->wq);
+		}
+	}
+}
+
+/**
+ * p9_poll_proc - polls all v9fs transports for new events and queues
+ * 	the appropriate work to the work queue
+ */
+static int p9_poll_proc(void *a)
+{
+	struct p9_conn *m, *mtmp;
+	struct p9_mux_poll_task *vpt;
+
+	vpt = a;
+	P9_DPRINTK(P9_DEBUG_MUX, "start %p %p\n", current, vpt);
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
+			p9_poll_mux(m);
+		}
+
+		P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
+		schedule_timeout(SCHED_TIMEOUT * HZ);
+	}
+
+	__set_current_state(TASK_RUNNING);
+	P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
+	return 0;
+}
+
+/**
+ * p9_write_work - called when a transport can send some data
+ */
+static void p9_write_work(struct work_struct *work)
+{
+	int n, err;
+	struct p9_conn *m;
+	struct p9_req *req;
+
+	m = container_of(work, struct p9_conn, wq);
+
+	if (m->err < 0) {
+		clear_bit(Wworksched, &m->wsched);
+		return;
+	}
+
+	if (!m->wsize) {
+		if (list_empty(&m->unsent_req_list)) {
+			clear_bit(Wworksched, &m->wsched);
+			return;
+		}
+
+		spin_lock(&m->lock);
+again:
+		req = list_entry(m->unsent_req_list.next, struct p9_req,
+			       req_list);
+		list_move_tail(&req->req_list, &m->req_list);
+		if (req->err == ERREQFLUSH)
+			goto again;
+
+		m->wbuf = req->tcall->sdata;
+		m->wsize = req->tcall->size;
+		m->wpos = 0;
+		spin_unlock(&m->lock);
+	}
+
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos,
+								m->wsize);
+	clear_bit(Wpending, &m->wsched);
+	err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
+	if (err == -EAGAIN) {
+		clear_bit(Wworksched, &m->wsched);
+		return;
+	}
+
+	if (err <= 0)
+		goto error;
+
+	m->wpos += err;
+	if (m->wpos == m->wsize)
+		m->wpos = m->wsize = 0;
+
+	if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
+		if (test_and_clear_bit(Wpending, &m->wsched))
+			n = POLLOUT;
+		else
+			n = m->trans->poll(m->trans, NULL);
+
+		if (n & POLLOUT) {
+			P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
+			queue_work(p9_mux_wq, &m->wq);
+		} else
+			clear_bit(Wworksched, &m->wsched);
+	} else
+		clear_bit(Wworksched, &m->wsched);
+
+	return;
+
+error:
+	p9_conn_cancel(m, err);
+	clear_bit(Wworksched, &m->wsched);
+}
+
+static void process_request(struct p9_conn *m, struct p9_req *req)
+{
+	int ecode;
+	struct p9_str *ename;
+
+	if (!req->err && req->rcall->id == P9_RERROR) {
+		ecode = req->rcall->params.rerror.errno;
+		ename = &req->rcall->params.rerror.error;
+
+		P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
+								ename->str);
+
+		if (*m->extended)
+			req->err = -ecode;
+
+		if (!req->err) {
+			req->err = p9_errstr2errno(ename->str, ename->len);
+
+			if (!req->err) {	/* string match failed */
+				PRINT_FCALL_ERROR("unknown error", req->rcall);
+			}
+
+			if (!req->err)
+				req->err = -ESERVERFAULT;
+		}
+	} else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
+		P9_DPRINTK(P9_DEBUG_ERROR,
+				"fcall mismatch: expected %d, got %d\n",
+				req->tcall->id + 1, req->rcall->id);
+		if (!req->err)
+			req->err = -EIO;
+	}
+}
+
+/**
+ * p9_read_work - called when there is some data to be read from a transport
+ */
+static void p9_read_work(struct work_struct *work)
+{
+	int n, err;
+	struct p9_conn *m;
+	struct p9_req *req, *rptr, *rreq;
+	struct p9_fcall *rcall;
+	char *rbuf;
+
+	m = container_of(work, struct p9_conn, rq);
+
+	if (m->err < 0)
+		return;
+
+	rcall = NULL;
+	P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
+
+	if (!m->rcall) {
+		m->rcall =
+		    kmalloc(sizeof(struct p9_fcall) + m->msize, GFP_KERNEL);
+		if (!m->rcall) {
+			err = -ENOMEM;
+			goto error;
+		}
+
+		m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
+		m->rpos = 0;
+	}
+
+	clear_bit(Rpending, &m->wsched);
+	err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
+	if (err == -EAGAIN) {
+		clear_bit(Rworksched, &m->wsched);
+		return;
+	}
+
+	if (err <= 0)
+		goto error;
+
+	m->rpos += err;
+	while (m->rpos > 4) {
+		n = le32_to_cpu(*(__le32 *) m->rbuf);
+		if (n >= m->msize) {
+			P9_DPRINTK(P9_DEBUG_ERROR,
+				"requested packet size too big: %d\n", n);
+			err = -EIO;
+			goto error;
+		}
+
+		if (m->rpos < n)
+			break;
+
+		err =
+		    p9_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
+		if (err < 0) {
+			goto error;
+		}
+
+#ifdef CONFIG_NET_9P_DEBUG
+		if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
+			char buf[150];
+
+			p9_printfcall(buf, sizeof(buf), m->rcall,
+				*m->extended);
+			printk(KERN_NOTICE ">>> %p %s\n", m, buf);
+		}
+#endif
+
+		rcall = m->rcall;
+		rbuf = m->rbuf;
+		if (m->rpos > n) {
+			m->rcall = kmalloc(sizeof(struct p9_fcall) + m->msize,
+					   GFP_KERNEL);
+			if (!m->rcall) {
+				err = -ENOMEM;
+				goto error;
+			}
+
+			m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
+			memmove(m->rbuf, rbuf + n, m->rpos - n);
+			m->rpos -= n;
+		} else {
+			m->rcall = NULL;
+			m->rbuf = NULL;
+			m->rpos = 0;
+		}
+
+		P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
+							rcall->id, rcall->tag);
+
+		req = NULL;
+		spin_lock(&m->lock);
+		list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
+			if (rreq->tag == rcall->tag) {
+				req = rreq;
+				if (req->flush != Flushing)
+					list_del(&req->req_list);
+				break;
+			}
+		}
+		spin_unlock(&m->lock);
+
+		if (req) {
+			req->rcall = rcall;
+			process_request(m, req);
+
+			if (req->flush != Flushing) {
+				if (req->cb)
+					(*req->cb) (req, req->cba);
+				else
+					kfree(req->rcall);
+
+				wake_up(&m->equeue);
+			}
+		} else {
+			if (err >= 0 && rcall->id != P9_RFLUSH)
+				P9_DPRINTK(P9_DEBUG_ERROR,
+				  "unexpected response mux %p id %d tag %d\n",
+				  m, rcall->id, rcall->tag);
+			kfree(rcall);
+		}
+	}
+
+	if (!list_empty(&m->req_list)) {
+		if (test_and_clear_bit(Rpending, &m->wsched))
+			n = POLLIN;
+		else
+			n = m->trans->poll(m->trans, NULL);
+
+		if (n & POLLIN) {
+			P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
+			queue_work(p9_mux_wq, &m->rq);
+		} else
+			clear_bit(Rworksched, &m->wsched);
+	} else
+		clear_bit(Rworksched, &m->wsched);
+
+	return;
+
+error:
+	p9_conn_cancel(m, err);
+	clear_bit(Rworksched, &m->wsched);
+}
+
+/**
+ * p9_send_request - send 9P request
+ * The function can sleep until the request is scheduled for sending.
+ * The function can be interrupted. Return from the function is not
+ * a guarantee that the request is sent successfully. Can return errors
+ * that can be retrieved by PTR_ERR macros.
+ *
+ * @m: mux data
+ * @tc: request to be sent
+ * @cb: callback function to call when response is received
+ * @cba: parameter to pass to the callback function
+ */
+static struct p9_req *p9_send_request(struct p9_conn *m,
+					  struct p9_fcall *tc,
+					  p9_conn_req_callback cb, void *cba)
+{
+	int n;
+	struct p9_req *req;
+
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
+		tc, tc->id);
+	if (m->err < 0)
+		return ERR_PTR(m->err);
+
+	req = kmalloc(sizeof(struct p9_req), GFP_KERNEL);
+	if (!req)
+		return ERR_PTR(-ENOMEM);
+
+	if (tc->id == P9_TVERSION)
+		n = P9_NOTAG;
+	else
+		n = p9_mux_get_tag(m);
+
+	if (n < 0)
+		return ERR_PTR(-ENOMEM);
+
+	p9_set_tag(tc, n);
+
+#ifdef CONFIG_NET_9P_DEBUG
+	if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
+		char buf[150];
+
+		p9_printfcall(buf, sizeof(buf), tc, *m->extended);
+		printk(KERN_NOTICE "<<< %p %s\n", m, buf);
+	}
+#endif
+
+	spin_lock_init(&req->lock);
+	req->tag = n;
+	req->tcall = tc;
+	req->rcall = NULL;
+	req->err = 0;
+	req->cb = cb;
+	req->cba = cba;
+	req->flush = None;
+
+	spin_lock(&m->lock);
+	list_add_tail(&req->req_list, &m->unsent_req_list);
+	spin_unlock(&m->lock);
+
+	if (test_and_clear_bit(Wpending, &m->wsched))
+		n = POLLOUT;
+	else
+		n = m->trans->poll(m->trans, NULL);
+
+	if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
+		queue_work(p9_mux_wq, &m->wq);
+
+	return req;
+}
+
+static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
+{
+	p9_mux_put_tag(m, req->tag);
+	kfree(req);
+}
+
+static void p9_mux_flush_cb(struct p9_req *freq, void *a)
+{
+	p9_conn_req_callback cb;
+	int tag;
+	struct p9_conn *m;
+	struct p9_req *req, *rreq, *rptr;
+
+	m = a;
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
+		freq->tcall, freq->rcall, freq->err,
+		freq->tcall->params.tflush.oldtag);
+
+	spin_lock(&m->lock);
+	cb = NULL;
+	tag = freq->tcall->params.tflush.oldtag;
+	req = NULL;
+	list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
+		if (rreq->tag == tag) {
+			req = rreq;
+			list_del(&req->req_list);
+			break;
+		}
+	}
+	spin_unlock(&m->lock);
+
+	if (req) {
+		spin_lock(&req->lock);
+		req->flush = Flushed;
+		spin_unlock(&req->lock);
+
+		if (req->cb)
+			(*req->cb) (req, req->cba);
+		else
+			kfree(req->rcall);
+
+		wake_up(&m->equeue);
+	}
+
+	kfree(freq->tcall);
+	kfree(freq->rcall);
+	p9_mux_free_request(m, freq);
+}
+
+static int
+p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
+{
+	struct p9_fcall *fc;
+	struct p9_req *rreq, *rptr;
+
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
+
+	/* if a response was received for a request, do nothing */
+	spin_lock(&req->lock);
+	if (req->rcall || req->err) {
+		spin_unlock(&req->lock);
+		P9_DPRINTK(P9_DEBUG_MUX,
+			"mux %p req %p response already received\n", m, req);
+		return 0;
+	}
+
+	req->flush = Flushing;
+	spin_unlock(&req->lock);
+
+	spin_lock(&m->lock);
+	/* if the request is not sent yet, just remove it from the list */
+	list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
+		if (rreq->tag == req->tag) {
+			P9_DPRINTK(P9_DEBUG_MUX,
+			   "mux %p req %p request is not sent yet\n", m, req);
+			list_del(&rreq->req_list);
+			req->flush = Flushed;
+			spin_unlock(&m->lock);
+			if (req->cb)
+				(*req->cb) (req, req->cba);
+			return 0;
+		}
+	}
+	spin_unlock(&m->lock);
+
+	clear_thread_flag(TIF_SIGPENDING);
+	fc = p9_create_tflush(req->tag);
+	p9_send_request(m, fc, p9_mux_flush_cb, m);
+	return 1;
+}
+
+static void
+p9_conn_rpc_cb(struct p9_req *req, void *a)
+{
+	struct p9_mux_rpc *r;
+
+	P9_DPRINTK(P9_DEBUG_MUX, "req %p r %p\n", req, a);
+	r = a;
+	r->rcall = req->rcall;
+	r->err = req->err;
+
+	if (req->flush != None && !req->err)
+		r->err = -ERESTARTSYS;
+
+	wake_up(&r->wqueue);
+}
+
+/**
+ * p9_mux_rpc - sends 9P request and waits until a response is available.
+ *	The function can be interrupted.
+ * @m: mux data
+ * @tc: request to be sent
+ * @rc: pointer where a pointer to the response is stored
+ */
+int
+p9_conn_rpc(struct p9_conn *m, struct p9_fcall *tc,
+	     struct p9_fcall **rc)
+{
+	int err, sigpending;
+	unsigned long flags;
+	struct p9_req *req;
+	struct p9_mux_rpc r;
+
+	r.err = 0;
+	r.tcall = tc;
+	r.rcall = NULL;
+	r.m = m;
+	init_waitqueue_head(&r.wqueue);
+
+	if (rc)
+		*rc = NULL;
+
+	sigpending = 0;
+	if (signal_pending(current)) {
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+	}
+
+	req = p9_send_request(m, tc, p9_conn_rpc_cb, &r);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
+		return err;
+	}
+
+	err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
+	if (r.err < 0)
+		err = r.err;
+
+	if (err == -ERESTARTSYS && m->trans->status == Connected
+							&& m->err == 0) {
+		if (p9_mux_flush_request(m, req)) {
+			/* wait until we get response of the flush message */
+			do {
+				clear_thread_flag(TIF_SIGPENDING);
+				err = wait_event_interruptible(r.wqueue,
+					r.rcall || r.err);
+			} while (!r.rcall && !r.err && err == -ERESTARTSYS &&
+				m->trans->status == Connected && !m->err);
+
+			err = -ERESTARTSYS;
+		}
+		sigpending = 1;
+	}
+
+	if (sigpending) {
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	}
+
+	if (rc)
+		*rc = r.rcall;
+	else
+		kfree(r.rcall);
+
+	p9_mux_free_request(m, req);
+	if (err > 0)
+		err = -EIO;
+
+	return err;
+}
+EXPORT_SYMBOL(p9_conn_rpc);
+
+#ifdef P9_NONBLOCK
+/**
+ * p9_conn_rpcnb - sends 9P request without waiting for response.
+ * @m: mux data
+ * @tc: request to be sent
+ * @cb: callback function to be called when response arrives
+ * @cba: value to pass to the callback function
+ */
+int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
+		   p9_conn_req_callback cb, void *a)
+{
+	int err;
+	struct p9_req *req;
+
+	req = p9_send_request(m, tc, cb, a);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
+		return PTR_ERR(req);
+	}
+
+	P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
+	return 0;
+}
+EXPORT_SYMBOL(p9_conn_rpcnb);
+#endif /* P9_NONBLOCK */
+
+/**
+ * p9_conn_cancel - cancel all pending requests with error
+ * @m: mux data
+ * @err: error code
+ */
+void p9_conn_cancel(struct p9_conn *m, int err)
+{
+	struct p9_req *req, *rtmp;
+	LIST_HEAD(cancel_list);
+
+	P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
+	m->err = err;
+	spin_lock(&m->lock);
+	list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
+		list_move(&req->req_list, &cancel_list);
+	}
+	list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
+		list_move(&req->req_list, &cancel_list);
+	}
+	spin_unlock(&m->lock);
+
+	list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
+		list_del(&req->req_list);
+		if (!req->err)
+			req->err = err;
+
+		if (req->cb)
+			(*req->cb) (req, req->cba);
+		else
+			kfree(req->rcall);
+	}
+
+	wake_up(&m->equeue);
+}
+EXPORT_SYMBOL(p9_conn_cancel);
+
+static u16 p9_mux_get_tag(struct p9_conn *m)
+{
+	int tag;
+
+	tag = p9_idpool_get(m->tagpool);
+	if (tag < 0)
+		return P9_NOTAG;
+	else
+		return (u16) tag;
+}
+
+static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
+{
+	if (tag != P9_NOTAG && p9_idpool_check(tag, m->tagpool))
+		p9_idpool_put(tag, m->tagpool);
+}
diff --git a/net/9p/sysctl.c b/net/9p/sysctl.c
new file mode 100644
index 000000000000..e7fe706ab95a
--- /dev/null
+++ b/net/9p/sysctl.c
@@ -0,0 +1,86 @@
+/*
+ *  net/9p/sysctl.c
+ *
+ *  9P sysctl interface
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sysctl.h>
+#include <linux/init.h>
+#include <net/9p/9p.h>
+
+enum {
+	P9_SYSCTL_NET = 487,
+	P9_SYSCTL_DEBUG = 1,
+};
+
+static ctl_table p9_table[] = {
+#ifdef CONFIG_NET_9P_DEBUG
+	{
+		.ctl_name       = P9_SYSCTL_DEBUG,
+		.procname       = "debug",
+		.data           = &p9_debug_level,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = &proc_dointvec
+	},
+#endif
+	{	.ctl_name	= 0 },
+};
+
+static ctl_table p9_net_table[] = {
+	{
+		.ctl_name	= P9_SYSCTL_NET,
+		.procname	= "9p",
+		.maxlen		= 0,
+		.mode		= 0555,
+		.child		= p9_table,
+	},
+	{	.ctl_name	= 0 },
+};
+
+static ctl_table p9_ctl_table[] = {
+	{
+		.ctl_name	= CTL_NET,
+		.procname	= "net",
+		.maxlen		= 0,
+		.mode		= 0555,
+		.child		= p9_net_table,
+	},
+	{	.ctl_name	= 0 },
+};
+
+static struct ctl_table_header *p9_table_header;
+
+int __init p9_sysctl_register(void)
+{
+	p9_table_header = register_sysctl_table(p9_ctl_table);
+	if (!p9_table_header)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void __exit p9_sysctl_unregister(void)
+{
+	 unregister_sysctl_table(p9_table_header);
+}
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
new file mode 100644
index 000000000000..fd636e94358f
--- /dev/null
+++ b/net/9p/trans_fd.c
@@ -0,0 +1,363 @@
+/*
+ * linux/fs/9p/trans_fd.c
+ *
+ * Fd transport layer.  Includes deprecated socket layer.
+ *
+ *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
+ *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
+ *  Copyright (C) 2004-2005 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/in.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/ipv6.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/un.h>
+#include <linux/uaccess.h>
+#include <linux/inet.h>
+#include <linux/idr.h>
+#include <linux/file.h>
+#include <net/9p/9p.h>
+#include <net/9p/transport.h>
+
+#define P9_PORT 564
+
+struct p9_trans_fd {
+	struct file *rd;
+	struct file *wr;
+};
+
+static int p9_socket_open(struct p9_transport *trans, struct socket *csocket);
+static int p9_fd_open(struct p9_transport *trans, int rfd, int wfd);
+static int p9_fd_read(struct p9_transport *trans, void *v, int len);
+static int p9_fd_write(struct p9_transport *trans, void *v, int len);
+static unsigned int p9_fd_poll(struct p9_transport *trans,
+						struct poll_table_struct *pt);
+static void p9_fd_close(struct p9_transport *trans);
+
+struct p9_transport *p9_trans_create_tcp(const char *addr, int port)
+{
+	int err;
+	struct p9_transport *trans;
+	struct socket *csocket;
+	struct sockaddr_in sin_server;
+
+	csocket = NULL;
+	trans = kmalloc(sizeof(struct p9_transport), GFP_KERNEL);
+	if (!trans)
+		return ERR_PTR(-ENOMEM);
+
+	trans->write = p9_fd_write;
+	trans->read = p9_fd_read;
+	trans->close = p9_fd_close;
+	trans->poll = p9_fd_poll;
+
+	sin_server.sin_family = AF_INET;
+	sin_server.sin_addr.s_addr = in_aton(addr);
+	sin_server.sin_port = htons(port);
+	sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &csocket);
+
+	if (!csocket) {
+		P9_EPRINTK(KERN_ERR, "p9_trans_tcp: problem creating socket\n");
+		err = -EIO;
+		goto error;
+	}
+
+	err = csocket->ops->connect(csocket,
+				    (struct sockaddr *)&sin_server,
+				    sizeof(struct sockaddr_in), 0);
+	if (err < 0) {
+		P9_EPRINTK(KERN_ERR,
+			"p9_trans_tcp: problem connecting socket to %s\n",
+			addr);
+		goto error;
+	}
+
+	err = p9_socket_open(trans, csocket);
+	if (err < 0)
+		goto error;
+
+	return trans;
+
+error:
+	if (csocket)
+		sock_release(csocket);
+
+	kfree(trans);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_trans_create_tcp);
+
+struct p9_transport *p9_trans_create_unix(const char *addr)
+{
+	int err;
+	struct socket *csocket;
+	struct sockaddr_un sun_server;
+	struct p9_transport *trans;
+
+	csocket = NULL;
+	trans = kmalloc(sizeof(struct p9_transport), GFP_KERNEL);
+	if (!trans)
+		return ERR_PTR(-ENOMEM);
+
+	trans->write = p9_fd_write;
+	trans->read = p9_fd_read;
+	trans->close = p9_fd_close;
+	trans->poll = p9_fd_poll;
+
+	if (strlen(addr) > UNIX_PATH_MAX) {
+		P9_EPRINTK(KERN_ERR, "p9_trans_unix: address too long: %s\n",
+			addr);
+		err = -ENAMETOOLONG;
+		goto error;
+	}
+
+	sun_server.sun_family = PF_UNIX;
+	strcpy(sun_server.sun_path, addr);
+	sock_create_kern(PF_UNIX, SOCK_STREAM, 0, &csocket);
+	err = csocket->ops->connect(csocket, (struct sockaddr *)&sun_server,
+			sizeof(struct sockaddr_un) - 1, 0);
+	if (err < 0) {
+		P9_EPRINTK(KERN_ERR,
+			"p9_trans_unix: problem connecting socket: %s: %d\n",
+			addr, err);
+		goto error;
+	}
+
+	err = p9_socket_open(trans, csocket);
+	if (err < 0)
+		goto error;
+
+	return trans;
+
+error:
+	if (csocket)
+		sock_release(csocket);
+
+	kfree(trans);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_trans_create_unix);
+
+struct p9_transport *p9_trans_create_fd(int rfd, int wfd)
+{
+	int err;
+	struct p9_transport *trans;
+
+	if (rfd == ~0 || wfd == ~0) {
+		printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
+		return ERR_PTR(-ENOPROTOOPT);
+	}
+
+	trans = kmalloc(sizeof(struct p9_transport), GFP_KERNEL);
+	if (!trans)
+		return ERR_PTR(-ENOMEM);
+
+	trans->write = p9_fd_write;
+	trans->read = p9_fd_read;
+	trans->close = p9_fd_close;
+	trans->poll = p9_fd_poll;
+
+	err = p9_fd_open(trans, rfd, wfd);
+	if (err < 0)
+		goto error;
+
+	return trans;
+
+error:
+	kfree(trans);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_trans_create_fd);
+
+static int p9_socket_open(struct p9_transport *trans, struct socket *csocket)
+{
+	int fd, ret;
+
+	csocket->sk->sk_allocation = GFP_NOIO;
+	fd = sock_map_fd(csocket);
+	if (fd < 0) {
+		P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to map fd\n");
+		return fd;
+	}
+
+	ret = p9_fd_open(trans, fd, fd);
+	if (ret < 0) {
+		P9_EPRINTK(KERN_ERR, "p9_socket_open: failed to open fd\n");
+		sockfd_put(csocket);
+		return ret;
+	}
+
+	((struct p9_trans_fd *)trans->priv)->rd->f_flags |= O_NONBLOCK;
+
+	return 0;
+}
+
+static int p9_fd_open(struct p9_transport *trans, int rfd, int wfd)
+{
+	struct p9_trans_fd *ts = kmalloc(sizeof(struct p9_trans_fd),
+					   GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->rd = fget(rfd);
+	ts->wr = fget(wfd);
+	if (!ts->rd || !ts->wr) {
+		if (ts->rd)
+			fput(ts->rd);
+		if (ts->wr)
+			fput(ts->wr);
+		kfree(ts);
+		return -EIO;
+	}
+
+	trans->priv = ts;
+	trans->status = Connected;
+
+	return 0;
+}
+
+/**
+ * p9_fd_read- read from a fd
+ * @v9ses: session information
+ * @v: buffer to receive data into
+ * @len: size of receive buffer
+ *
+ */
+static int p9_fd_read(struct p9_transport *trans, void *v, int len)
+{
+	int ret;
+	struct p9_trans_fd *ts = NULL;
+
+	if (trans && trans->status != Disconnected)
+		ts = trans->priv;
+
+	if (!ts)
+		return -EREMOTEIO;
+
+	if (!(ts->rd->f_flags & O_NONBLOCK))
+		P9_DPRINTK(P9_DEBUG_ERROR, "blocking read ...\n");
+
+	ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
+	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
+		trans->status = Disconnected;
+	return ret;
+}
+
+/**
+ * p9_fd_write - write to a socket
+ * @v9ses: session information
+ * @v: buffer to send data from
+ * @len: size of send buffer
+ *
+ */
+static int p9_fd_write(struct p9_transport *trans, void *v, int len)
+{
+	int ret;
+	mm_segment_t oldfs;
+	struct p9_trans_fd *ts = NULL;
+
+	if (trans && trans->status != Disconnected)
+		ts = trans->priv;
+
+	if (!ts)
+		return -EREMOTEIO;
+
+	if (!(ts->wr->f_flags & O_NONBLOCK))
+		P9_DPRINTK(P9_DEBUG_ERROR, "blocking write ...\n");
+
+	oldfs = get_fs();
+	set_fs(get_ds());
+	/* The cast to a user pointer is valid due to the set_fs() */
+	ret = vfs_write(ts->wr, (void __user *)v, len, &ts->wr->f_pos);
+	set_fs(oldfs);
+
+	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
+		trans->status = Disconnected;
+	return ret;
+}
+
+static unsigned int
+p9_fd_poll(struct p9_transport *trans, struct poll_table_struct *pt)
+{
+	int ret, n;
+	struct p9_trans_fd *ts = NULL;
+	mm_segment_t oldfs;
+
+	if (trans && trans->status == Connected)
+		ts = trans->priv;
+
+	if (!ts)
+		return -EREMOTEIO;
+
+	if (!ts->rd->f_op || !ts->rd->f_op->poll)
+		return -EIO;
+
+	if (!ts->wr->f_op || !ts->wr->f_op->poll)
+		return -EIO;
+
+	oldfs = get_fs();
+	set_fs(get_ds());
+
+	ret = ts->rd->f_op->poll(ts->rd, pt);
+	if (ret < 0)
+		goto end;
+
+	if (ts->rd != ts->wr) {
+		n = ts->wr->f_op->poll(ts->wr, pt);
+		if (n < 0) {
+			ret = n;
+			goto end;
+		}
+		ret = (ret & ~POLLOUT) | (n & ~POLLIN);
+	}
+
+end:
+	set_fs(oldfs);
+	return ret;
+}
+
+/**
+ * p9_sock_close - shutdown socket
+ * @trans: private socket structure
+ *
+ */
+static void p9_fd_close(struct p9_transport *trans)
+{
+	struct p9_trans_fd *ts;
+
+	if (!trans)
+		return;
+
+	ts = xchg(&trans->priv, NULL);
+
+	if (!ts)
+		return;
+
+	trans->status = Disconnected;
+	if (ts->rd)
+		fput(ts->rd);
+	if (ts->wr)
+		fput(ts->wr);
+	kfree(ts);
+}
+
diff --git a/net/9p/util.c b/net/9p/util.c
new file mode 100644
index 000000000000..22077b79395d
--- /dev/null
+++ b/net/9p/util.c
@@ -0,0 +1,125 @@
+/*
+ *  net/9p/util.c
+ *
+ *  This file contains some helper functions
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/parser.h>
+#include <linux/idr.h>
+#include <net/9p/9p.h>
+
+struct p9_idpool {
+	struct semaphore lock;
+	struct idr pool;
+};
+
+struct p9_idpool *p9_idpool_create(void)
+{
+	struct p9_idpool *p;
+
+	p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL);
+	if (!p)
+		return ERR_PTR(-ENOMEM);
+
+	init_MUTEX(&p->lock);
+	idr_init(&p->pool);
+
+	return p;
+}
+EXPORT_SYMBOL(p9_idpool_create);
+
+void p9_idpool_destroy(struct p9_idpool *p)
+{
+	idr_destroy(&p->pool);
+	kfree(p);
+}
+EXPORT_SYMBOL(p9_idpool_destroy);
+
+/**
+ * p9_idpool_get - allocate numeric id from pool
+ * @p - pool to allocate from
+ *
+ * XXX - This seems to be an awful generic function, should it be in idr.c with
+ *            the lock included in struct idr?
+ */
+
+int p9_idpool_get(struct p9_idpool *p)
+{
+	int i = 0;
+	int error;
+
+retry:
+	if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
+		return 0;
+
+	if (down_interruptible(&p->lock) == -EINTR) {
+		P9_EPRINTK(KERN_WARNING, "Interrupted while locking\n");
+		return -1;
+	}
+
+	/* no need to store exactly p, we just need something non-null */
+	error = idr_get_new(&p->pool, p, &i);
+	up(&p->lock);
+
+	if (error == -EAGAIN)
+		goto retry;
+	else if (error)
+		return -1;
+
+	return i;
+}
+EXPORT_SYMBOL(p9_idpool_get);
+
+/**
+ * p9_idpool_put - release numeric id from pool
+ * @p - pool to allocate from
+ *
+ * XXX - This seems to be an awful generic function, should it be in idr.c with
+ *            the lock included in struct idr?
+ */
+
+void p9_idpool_put(int id, struct p9_idpool *p)
+{
+	if (down_interruptible(&p->lock) == -EINTR) {
+		P9_EPRINTK(KERN_WARNING, "Interrupted while locking\n");
+		return;
+	}
+	idr_remove(&p->pool, id);
+	up(&p->lock);
+}
+EXPORT_SYMBOL(p9_idpool_put);
+
+/**
+ * p9_idpool_check - check if the specified id is available
+ * @id - id to check
+ * @p - pool
+ */
+int p9_idpool_check(int id, struct p9_idpool *p)
+{
+	return idr_find(&p->pool, id) != NULL;
+}
+EXPORT_SYMBOL(p9_idpool_check);
diff --git a/net/Kconfig b/net/Kconfig
index f3de72978ab6..cdba08ca2efe 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -227,6 +227,7 @@ source "net/ieee80211/Kconfig"
 endmenu
 
 source "net/rfkill/Kconfig"
+source "net/9p/Kconfig"
 
 endif   # if NET
 endmenu # Networking
diff --git a/net/Makefile b/net/Makefile
index a87a88963432..bbe7d2a41486 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_TIPC)		+= tipc/
 obj-$(CONFIG_NETLABEL)		+= netlabel/
 obj-$(CONFIG_IUCV)		+= iucv/
 obj-$(CONFIG_RFKILL)		+= rfkill/
+obj-$(CONFIG_NET_9P)		+= 9p/
 
 ifeq ($(CONFIG_NET),y)
 obj-$(CONFIG_SYSCTL)		+= sysctl_net.o