This patch implements the basic functionality required for implementing
in-kernel 9P file servers.

Signed-off-by: Latchesar Ionkov <[EMAIL PROTECTED]>

---
 include/net/9p/9p.h  |    2 +
 include/net/9p/srv.h |  169 +++++++
 net/9p/Kconfig       |    5 +
 net/9p/Makefile      |    4 +
 net/9p/fcprint.c     |    2 +
 net/9p/srv.c         | 1283 ++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 1465 insertions(+), 0 deletions(-)

diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index f7bd839..a913cdb 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -65,6 +65,7 @@ do { \
 
 /* Message Types */
 enum {
+       P9_FIRST = 100,
        P9_TVERSION = 100,
        P9_RVERSION,
        P9_TAUTH = 102,
@@ -93,6 +94,7 @@ enum {
        P9_RSTAT,
        P9_TWSTAT = 126,
        P9_RWSTAT,
+       P9_LAST,
 };
 
 /* open modes */
diff --git a/include/net/9p/srv.h b/include/net/9p/srv.h
new file mode 100644
index 0000000..72d011e
--- /dev/null
+++ b/include/net/9p/srv.h
@@ -0,0 +1,169 @@
+/*
+ * include/net/9p/srv.h
+ *
+ * 9P server definitions.
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <[EMAIL PROTECTED]>
+ *
+ *  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
+ *
+ */
+
+#ifndef NET_9PSRV_H
+#define NET_9PSRV_H
+
+#define P9SRV_DEBUG_SRV                (1<<16)
+#define P9SRV_DEBUG_CONN       (1<<17)
+#define P9SRV_DEBUG_FID                (1<<18)
+#define P9SRV_DEBUG_REQ                (1<<19)
+#define P9SRV_DEBUG_FCALL      (1<<20)
+#define P9SRV_DEBUG_FS         (1<<21)
+
+#define MAXPOLLWADDR   2
+
+struct p9srv;
+struct p9srv_fid;
+struct p9srv_fidpool;
+struct p9srv_conn;
+struct p9srv_req;
+
+struct p9srv {
+       int                     msize;
+       int                     dotu;           /* 9P2000.u */
+       void                    *srvaux;
+       void                    *treeaux;
+       int                     debuglevel;
+       void                    (*start)(struct p9srv *);
+       void                    (*stop)(struct p9srv *);
+       void                    (*destroy)(struct p9srv *);
+       void                    (*connopen)(struct p9srv_conn *);
+       void                    (*connclose)(struct p9srv_conn *);
+       void                    (*fiddestroy)(struct p9srv_fid *);
+       void                    (*reqdestroy)(struct p9srv_req *);
+
+       /* 9P message handlers */
+       void                    (*attach)(struct p9srv_req *);
+       void                    (*auth)(struct p9srv_req *);
+       int                     (*flush)(struct p9srv_req *);
+       void                    (*walk)(struct p9srv_req *);
+       void                    (*open)(struct p9srv_req *);
+       void                    (*create)(struct p9srv_req *);
+       void                    (*read)(struct p9srv_req *);
+       void                    (*write)(struct p9srv_req *);
+       void                    (*clunk)(struct p9srv_req *);
+       void                    (*remove)(struct p9srv_req *);
+       void                    (*stat)(struct p9srv_req *);
+       void                    (*wstat)(struct p9srv_req *);
+
+       /* implementation specific */
+       atomic_t                refcount;
+       spinlock_t              lock;           /* covers all srv fields */
+       struct list_head        conn_list;      /* all connections for srv */
+       struct list_head        req_list;       /* requests not yet worked on */
+       struct list_head        workreq_list;   /* requests being worked on */
+};
+
+struct p9srv_conn {
+       struct p9srv            *srv;
+       struct p9_trans         *trans;
+       int                     msize;
+       int                     dotu;   /* 9P2000.u */
+
+       /* implementation specific */
+       unsigned long           status;
+       struct p9srv_fidpool    *fidpool;
+       struct list_head        conn_list;
+       atomic_t                reset_wcount;
+       wait_queue_head_t       reset_wqueue;
+};
+
+enum {
+       /* connection status values */
+       Reset = 1,              /* resetting */
+       Destroy = 2,            /* destroying */
+};
+
+struct p9srv_fid {
+       u32                     fid;
+       atomic_t                refcount;
+       struct p9srv_conn       *conn;
+       void                    *aux;
+       u16                     omode;
+       u8                      type;
+       u32                     diroffset;
+       u32                     uid;
+
+       /* implementation specific */
+       struct p9srv_fidpool    *fidpool;
+       struct hlist_node       fid_list;
+};
+
+#define FID_HTABLE_BITS                5
+#define FID_HTABLE_SIZE                (1 << FID_HTABLE_BITS)
+
+struct p9srv_req {
+       int                     tag;
+       void                    *aux;
+       struct p9_fcall         *tcall;
+       struct p9_fcall         *rcall;
+       struct p9srv_fid        *fid;
+       struct p9srv_fid        *afid;          /* Tauth, Tattach */
+       struct p9srv_fid        *newfid;        /* Twalk */
+
+       /* implementation specific */
+       long                    status;
+       atomic_t                refcount;
+       struct p9srv_conn       *conn;
+       struct p9_trans_req     *req;
+       struct list_head        flush_req_list;
+       struct list_head        req_list;
+       struct work_struct      pq;
+};
+
+extern char *Eunknownfid;
+extern char *Enomem;
+extern char *Enoauth;
+extern char *Enotimpl;
+extern char *Einuse;
+extern char *Ebadusefid;
+extern char *Enotdir;
+extern char *Etoomanywnames;
+extern char *Eperm;
+extern char *Etoolarge;
+extern char *Ebadoffset;
+extern char *Edirchange;
+extern char *Enotfound;
+extern char *Eopen;
+extern char *Eexist;
+extern char *Enotempty;
+
+
+struct p9srv *p9srv_srv_create(void);
+void p9srv_srv_stop(struct p9srv *srv);
+void p9srv_srv_destroy(struct p9srv *srv);
+void p9srv_srv_start(struct p9srv *srv);
+void p9srv_respond(struct p9srv_req *req, struct p9_fcall *rc);
+void p9srv_respond_error(struct p9srv_req *req, char *ename, int ecode);
+struct p9srv_req *p9srv_req_create(void);
+void p9srv_req_ref(struct p9srv_req *req);
+void p9srv_req_unref(struct p9srv_req *req);
+struct p9srv_conn *p9srv_conn_create(struct p9srv *srv, struct p9_trans 
*trans);
+void p9srv_conn_destroy(struct p9srv_conn *conn);
+struct p9srv_fid *p9srv_fid_find(struct p9srv_fidpool *fp, u32 fid);
+void p9srv_fid_incref(struct p9srv_fid *fid);
+void p9srv_fid_decref(struct p9srv_fid *fid);
+
+#endif
diff --git a/net/9p/Kconfig b/net/9p/Kconfig
index bafc50c..8a3ff32 100644
--- a/net/9p/Kconfig
+++ b/net/9p/Kconfig
@@ -23,6 +23,11 @@ config NET_9P_FD
          file descriptors.  TCP/IP is the default transport for 9p,
          so if you are going to use 9p, you'll likely want this.
 
+config NET_9P_SRV
+       tristate "9P server support"
+       depends on NET_9P
+       help
+         Say Y if you want the 9P server support
 config NET_9P_VIRTIO
        depends on NET_9P && EXPERIMENTAL && VIRTIO
        tristate "9P Virtio Transport (Experimental)"
diff --git a/net/9p/Makefile b/net/9p/Makefile
index 87c0fa5..106a596 100644
--- a/net/9p/Makefile
+++ b/net/9p/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_NET_9P) := 9pnet.o
 obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
+obj-$(CONFIG_NET_9P_SRV) += 9psrv.o
 obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 
 9pnet-objs := \
@@ -10,6 +11,9 @@ obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
        fcprint.o \
        util.o \
 
+9psrv-objs := \
+       srv.o \
+
 9pnet_fd-objs := \
        mux.o \
 
diff --git a/net/9p/fcprint.c b/net/9p/fcprint.c
index b1ae8ec..3c5cd83 100644
--- a/net/9p/fcprint.c
+++ b/net/9p/fcprint.c
@@ -347,8 +347,10 @@ p9_printfcall(char *buf, int buflen, struct p9_fcall *fc, 
int extended)
 
        return ret;
 }
+EXPORT_SYMBOL(p9_printfcall);
 
 #else
+
 int
 p9_printfcall(char *buf, int buflen, struct p9_fcall *fc, int extended)
 {
diff --git a/net/9p/srv.c b/net/9p/srv.c
new file mode 100644
index 0000000..b35f090
--- /dev/null
+++ b/net/9p/srv.c
@@ -0,0 +1,1283 @@
+/*
+ * net/9p/srv.c
+ *
+ * 9P Server Support
+ *
+ *  Copyright (C) 2007 by Latchesar Ionkov <[EMAIL PROTECTED]>
+ *
+ *  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/parser.h>
+#include <linux/hash.h>
+#include <net/9p/9p.h>
+#include <net/9p/transport.h>
+#include <net/9p/srv.h>
+
+struct p9srv_fidpool {
+       spinlock_t              lock;   /* covers all fidpool operations */
+       struct hlist_head       hash[FID_HTABLE_SIZE];
+};
+
+enum {
+       /* p9srv_req status */
+       Respond = 1,
+       Flush,
+       Flushwork,
+};
+
+struct workqueue_struct *p9srv_wq;
+
+char *Eunknownfid = "unknown fid";
+EXPORT_SYMBOL(Eunknownfid);
+char *Enomem = "no memory";
+EXPORT_SYMBOL(Enomem);
+char *Enoauth = "no authentication required";
+EXPORT_SYMBOL(Enoauth);
+char *Enotimpl = "not implemented";
+EXPORT_SYMBOL(Enotimpl);
+char *Einuse = "fid already exists";
+EXPORT_SYMBOL(Einuse);
+char *Ebadusefid = "bad use of fid";
+EXPORT_SYMBOL(Ebadusefid);
+char *Enotdir = "not a directory";
+EXPORT_SYMBOL(Enotdir);
+char *Etoomanywnames = "too many wnames";
+EXPORT_SYMBOL(Etoomanywnames);
+char *Eperm = "permission denied";
+EXPORT_SYMBOL(Eperm);
+char *Etoolarge = "i/o count too large";
+EXPORT_SYMBOL(Etoolarge);
+char *Ebadoffset = "bad offset in directory read";
+EXPORT_SYMBOL(Ebadoffset);
+char *Edirchange = "cannot convert between files and directories";
+EXPORT_SYMBOL(Edirchange);
+char *Enotfound = "file not found";
+EXPORT_SYMBOL(Enotfound);
+char *Eopen = "file alread exclusively opened";
+EXPORT_SYMBOL(Eopen);
+char *Eexist = "file or directory already exists";
+EXPORT_SYMBOL(Eexist);
+char *Enotempty = "directory not empty";
+EXPORT_SYMBOL(Enotempty);
+
+static void p9srv_srv_ref(struct p9srv *srv);
+static void p9srv_srv_unref(struct p9srv *srv);
+static void p9srv_conn_reset(struct p9srv_conn *conn, struct p9srv_req *vreq);
+static void p9srv_conn_respond(struct p9srv_req *req);
+static struct p9srv_fidpool *p9srv_fidpool_create(void);
+static void p9srv_fidpool_destroy(struct p9srv_fidpool *fp);
+static void p9srv_fidpool_reset(struct p9srv_fidpool *fp);
+struct p9srv_fid *p9srv_fid_create(struct p9srv_fidpool *fp, u32 fid);
+static void p9srv_version(struct p9srv_req *);
+static void p9srv_auth(struct p9srv_req *);
+static void p9srv_attach(struct p9srv_req *);
+static void p9srv_attach_post(struct p9srv_req *req);
+static void p9srv_flush(struct p9srv_req *);
+static void p9srv_walk(struct p9srv_req *);
+static void p9srv_walk_post(struct p9srv_req *);
+static void p9srv_open(struct p9srv_req *);
+static void p9srv_open_post(struct p9srv_req *);
+static void p9srv_create(struct p9srv_req *);
+static void p9srv_create_post(struct p9srv_req *);
+static void p9srv_read(struct p9srv_req *);
+static void p9srv_read_post(struct p9srv_req *);
+static void p9srv_write(struct p9srv_req *);
+static void p9srv_clunk(struct p9srv_req *);
+static void p9srv_clunk_post(struct p9srv_req *);
+static void p9srv_remove(struct p9srv_req *);
+static void p9srv_remove_post(struct p9srv_req *);
+static void p9srv_stat(struct p9srv_req *);
+static void p9srv_wstat(struct p9srv_req *);
+static void p9srv_preq_work(struct work_struct *work);
+static void p9srv_conn_request(struct p9_trans *, struct p9_trans_req *req);
+
+static void (*p9srv_fcall[])(struct p9srv_req *) = {
+       p9srv_version,          /* Tversion */
+       p9srv_auth,             /* Tauth */
+       p9srv_attach,           /* Tattach */
+       NULL,                   /* Terror */
+       p9srv_flush,            /* Tflush */
+       p9srv_walk,             /* Twalk */
+       p9srv_open,             /* Topen */
+       p9srv_create,           /* Tcreate */
+       p9srv_read,             /* Tread */
+       p9srv_write,            /* Twrite */
+       p9srv_clunk,            /* Tclunk */
+       p9srv_remove,           /* Tremove */
+       p9srv_stat,             /* Tstat */
+       p9srv_wstat,            /* Twstat */
+};
+
+static void (*p9srv_fcall_post[])(struct p9srv_req *) = {
+       NULL,                   /* Tversion */
+       NULL,                   /* Tauth */
+       p9srv_attach_post,      /* Tattach */
+       NULL,                   /* Terror */
+       NULL,                   /* Tflush */
+       p9srv_walk_post,        /* Twalk */
+       p9srv_open_post,        /* Topen */
+       p9srv_create_post,      /* Tcreate */
+       p9srv_read_post,        /* Tread */
+       NULL,                   /* Twrite */
+       p9srv_clunk_post,       /* Tclunk */
+       p9srv_remove_post,      /* Tremove */
+       NULL,                   /* Tstat */
+       NULL,                   /* Twstat */
+};
+
+struct p9srv *p9srv_srv_create(void)
+{
+       struct p9srv *srv;
+
+       srv = kmalloc(sizeof(struct p9srv), GFP_KERNEL);
+       if (!srv) {
+               P9_DPRINTK(P9SRV_DEBUG_SRV, "failed\n");
+               return ERR_PTR(-ENOMEM);
+       }
+
+       memset(srv, 0, sizeof(struct p9srv));
+       spin_lock_init(&srv->lock);
+       atomic_set(&srv->refcount, 1);
+       INIT_LIST_HEAD(&srv->conn_list);
+       INIT_LIST_HEAD(&srv->req_list);
+       INIT_LIST_HEAD(&srv->workreq_list);
+
+       /* the values below may be overwritten by the creator */
+       srv->msize = 65536 + P9_IOHDRSZ;
+       srv->dotu = 1;
+       srv->debuglevel = 0;
+
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "srv %p\n", srv);
+       return srv;
+}
+EXPORT_SYMBOL(p9srv_srv_create);
+
+void p9srv_srv_destroy(struct p9srv *srv)
+{
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "%p\n", srv);
+       p9srv_srv_unref(srv);
+}
+EXPORT_SYMBOL(p9srv_srv_destroy);
+
+void p9srv_srv_ref(struct p9srv *srv)
+{
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "%p\n", srv);
+       atomic_inc(&srv->refcount);
+}
+
+void p9srv_srv_unref(struct p9srv *srv)
+{
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "%p\n", srv);
+       if (atomic_dec_and_test(&srv->refcount)) {
+               P9_DPRINTK(P9SRV_DEBUG_SRV, "destroy %p\n", srv);
+               BUG_ON(!list_empty(&srv->conn_list));
+               BUG_ON(!list_empty(&srv->req_list));
+               BUG_ON(!list_empty(&srv->workreq_list));
+
+               if (srv->destroy)
+                       (*srv->destroy)(srv);
+
+               kfree(srv);
+       }
+}
+
+void p9srv_srv_start(struct p9srv *srv)
+{
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "%p\n", srv);
+       if (srv->start)
+               (*srv->start)(srv);
+}
+EXPORT_SYMBOL(p9srv_srv_start);
+
+void p9srv_srv_stop(struct p9srv *srv)
+{
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "%p\n", srv);
+       if (srv->stop)
+               (*srv->stop)(srv);
+       p9srv_srv_unref(srv);
+}
+EXPORT_SYMBOL(p9srv_srv_stop);
+
+/**
+ * p9_preq_work - process a single request
+ */
+static void p9srv_preq_work(struct work_struct *work)
+{
+       struct p9srv *srv;
+       struct p9srv_req *req;
+       struct p9_fcall *tc;
+
+       req = container_of(work, struct p9srv_req, pq);
+       P9_DPRINTK(P9SRV_DEBUG_SRV, "req %p tag %d\n", req, req->tag);
+       srv = req->conn->srv;
+       spin_lock(&srv->lock);
+       list_move_tail(&req->req_list, &srv->workreq_list);
+       if (test_bit(Flush, &req->status) || test_bit(Flushwork, &req->status)) 
{
+               P9_DPRINTK(P9SRV_DEBUG_SRV, "req %p tag %d flushed\n", req, 
req->tag);
+               spin_unlock(&srv->lock);
+               p9srv_respond(req, NULL);
+               return;
+       }
+
+       spin_unlock(&srv->lock);
+       tc = req->tcall;
+       if (tc->id < P9_FIRST || tc->id > P9_LAST ||
+               !p9srv_fcall[(tc->id - P9_FIRST)/2] || tc->id%2 == 1) {
+
+               p9srv_respond_error(req, "unsupported message", EIO);
+               return;
+       }
+
+       (*p9srv_fcall[(tc->id - P9_FIRST) / 2])(req);
+}
+
+void p9srv_respond(struct p9srv_req *req, struct p9_fcall *rc)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_req *freq, *rtmp;
+
+       conn = req->conn;
+       srv = conn->srv;
+       P9_DPRINTK(P9SRV_DEBUG_REQ, "srv %p conn %p req %p\n", srv, conn, req);
+
+       if (test_and_set_bit(Respond, &req->status)) {
+               kfree(rc);
+               if (rc != req->rcall)
+                       kfree(req->rcall);
+               return;
+       }
+
+       spin_lock(&srv->lock);
+       list_del(&req->req_list);
+       list_for_each_entry(freq, &req->flush_req_list, flush_req_list) {
+               list_del(&freq->req_list);
+       }
+       spin_unlock(&srv->lock);
+
+       if (test_bit(Flush, &req->status) && rc == NULL)
+               goto flush;
+
+       p9_set_tag(rc, req->tag);
+       if (req->rcall != rc)
+               kfree(req->rcall);
+
+       req->rcall = rc;
+       if (req->tcall->id >= P9_FIRST && req->tcall->id < P9_LAST &&
+                       p9srv_fcall_post[(req->tcall->id - P9_FIRST) / 2])
+               (*p9srv_fcall_post[(req->tcall->id - P9_FIRST) / 2])(req);
+
+       p9srv_fid_decref(req->fid);
+       p9srv_fid_decref(req->newfid);
+       p9srv_fid_decref(req->afid);
+       req->fid = NULL;
+       req->newfid = NULL;
+       req->afid = NULL;
+
+       p9srv_req_ref(req);
+       p9srv_conn_respond(req);
+
+flush:
+       list_for_each_entry_safe(freq, rtmp, &req->flush_req_list, 
flush_req_list) {
+               p9_set_tag(freq->rcall, freq->tag);
+               p9srv_conn_respond(freq);
+       }
+       p9srv_req_unref(req);
+}
+EXPORT_SYMBOL(p9srv_respond);
+
+void p9srv_respond_error(struct p9srv_req *req, char *ename, int ecode)
+{
+       P9_DPRINTK(P9SRV_DEBUG_REQ, "req %p ename %s ecode %d\n",
+               req, ename, ecode);
+       p9_create_rerror(req->rcall, ename, ecode, req->conn->dotu);
+       p9srv_respond(req, req->rcall);
+}
+EXPORT_SYMBOL(p9srv_respond_error);
+
+struct p9srv_req *p9srv_req_create(void)
+{
+       struct p9srv_req *req;
+
+       req = kmalloc(sizeof(struct p9srv_req), GFP_KERNEL);
+       if (!req)
+               return ERR_PTR(-ENOMEM);
+
+       req->tag = P9_NOTAG;
+       req->aux = NULL;
+       req->tcall = NULL;
+       req->rcall = NULL;
+       req->status = 0;
+       atomic_set(&req->refcount, 1);
+       req->conn = NULL;
+       req->req = NULL;
+       INIT_LIST_HEAD(&req->flush_req_list);
+       INIT_LIST_HEAD(&req->req_list);
+       INIT_WORK(&req->pq, p9srv_preq_work);
+       req->fid = NULL;
+       req->afid = NULL;
+       req->newfid = NULL;
+       P9_DPRINTK(P9SRV_DEBUG_REQ, "req %p\n", req);
+
+       return req;
+}
+
+void p9srv_req_ref(struct p9srv_req *req)
+{
+       atomic_inc(&req->refcount);
+       P9_DPRINTK(P9SRV_DEBUG_REQ, "req %p count %d\n", req,
+               atomic_read(&req->refcount));
+}
+EXPORT_SYMBOL(p9srv_req_ref);
+
+void p9srv_req_unref(struct p9srv_req *req)
+{
+       int n;
+
+       n = atomic_dec_and_test(&req->refcount);
+       P9_DPRINTK(P9SRV_DEBUG_REQ, "req %p count %d\n", req,
+               atomic_read(&req->refcount));
+       if (n) {
+               P9_DPRINTK(P9SRV_DEBUG_REQ, "destroy req %p\n", req);
+               if (req->conn && req->conn->srv && req->conn->srv->reqdestroy)
+                       (*req->conn->srv->reqdestroy)(req);
+
+               kfree(req);
+       }
+}
+EXPORT_SYMBOL(p9srv_req_unref);
+
+static void p9srv_version(struct p9srv_req *req)
+{
+       int msize;
+       struct p9_str *version;
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9_fcall *tc;
+
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       msize = tc->params.tversion.msize;
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (msize < P9_IOHDRSZ + 1) {
+               p9srv_respond_error(req, "msize too small", EIO);
+               return;
+       }
+
+       version = &tc->params.tversion.version;
+       if ((version->len != 8 || memcmp(version->str, "9P2000.u", 8)) &&
+               (version->len != 6 || memcmp(version->str, "9P2000", 6))) {
+
+               p9srv_respond_error(req, "unsupported protocol version", EIO);
+               return;
+       }
+
+       p9srv_conn_reset(conn, req);
+       p9_create_rversion(req->rcall, conn->msize,
+               conn->dotu?"9P2000.u":"9P2000");
+       p9srv_respond(req, req->rcall);
+}
+
+static void p9srv_auth(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9_fcall *tc;
+       struct p9srv_fid *afid;
+
+       srv = req->conn->srv;
+       tc = req->tcall;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       afid = p9srv_fid_create(req->conn->fidpool, tc->params.tauth.afid);
+       if (IS_ERR(afid)) {
+               p9srv_respond_error(req, Ebadusefid, PTR_ERR(afid));
+               return;
+       }
+
+       afid->conn = req->conn;
+       afid->type = P9_QTAUTH;
+       req->afid = afid;
+       if (*srv->auth)
+               (*srv->auth)(req);
+       else
+               p9srv_respond_error(req, "authentication not required", EIO);
+}
+
+static void p9srv_attach(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *afid, *fid;
+       struct p9_fcall *tc;
+
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       afid = NULL;
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (tc->params.tattach.afid != P9_NOFID) {
+               afid = p9srv_fid_find(conn->fidpool, tc->params.tattach.afid);
+               if (IS_ERR(afid)) {
+                       p9srv_respond_error(req, Eunknownfid, PTR_ERR(afid));
+                       return;
+               }
+
+               req->afid = afid;
+               if (!(afid->type & P9_QTAUTH)) {
+                       p9srv_respond_error(req, Ebadusefid, EIO);
+                       return;
+               }
+       }
+
+       fid = p9srv_fid_create(conn->fidpool, tc->params.tattach.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Ebadusefid, PTR_ERR(fid));
+               return;
+       }
+       fid->conn = req->conn;
+       req->fid = fid;
+       if (*srv->attach)
+               (*srv->attach)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_attach_post(struct p9srv_req *req)
+{
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (req->rcall && req->rcall->id == P9_RATTACH) {
+               req->fid->type = req->rcall->params.rattach.qid.type;
+               p9srv_fid_incref(req->fid);
+       }
+}
+
+/* if 0 returned, the flush request needs to be queued for response */
+static int p9srv_flush_req(struct p9srv_req *freq)
+{
+       int oldtag;
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_req *req;
+
+       conn = freq->conn;
+       srv = conn->srv;
+       oldtag = freq->tcall->params.tflush.oldtag;
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p tag %d oldtag %d\n", freq,
+               freq->tag, oldtag);
+       p9_create_rflush(freq->rcall);
+       if (oldtag == freq->tag)
+               return 0;
+
+       spin_lock(&srv->lock);
+       /* if the server didn't start working on the request, mark it as
+          being flushed, but don't call srv->flush */
+       list_for_each_entry(req, &srv->req_list, req_list) {
+               if (req->conn == conn && req->tag == oldtag) {
+                       P9_DPRINTK(P9SRV_DEBUG_FCALL, "found in pending oldtag 
%d\n", oldtag);
+                       list_add_tail(&freq->flush_req_list,
+                               &req->flush_req_list);
+                       set_bit(Flush, &req->status);
+                       spin_unlock(&srv->lock);
+                       return 1;
+               }
+       }
+
+       list_for_each_entry(req, &srv->workreq_list, req_list) {
+               if (req->conn == conn && req->tag == oldtag) {
+                       P9_DPRINTK(P9SRV_DEBUG_FCALL, "found in working oldtag 
%d\n", oldtag);
+                       list_add_tail(&freq->flush_req_list,
+                               &req->flush_req_list);
+
+
+                       if (test_and_set_bit(Flushwork, &req->status)) {
+                               spin_unlock(&srv->lock);
+                               return 1;
+                       }
+
+                       p9srv_req_ref(req);
+                       spin_unlock(&srv->lock);
+                       if (srv->flush && (*srv->flush)(req)) {
+                               /* if srv->flush returns non-zero, the
+                                  fs is not planning to respond to the
+                                  request. So we queue it once more
+                                  and the Flushwork status will do the right
+                                  thing */
+
+                               queue_work(p9srv_wq, &req->pq);
+                       }
+
+                       p9srv_req_unref(req);
+                       return 1;
+               }
+       }
+       spin_unlock(&srv->lock);
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "not found oldtag %d\n", oldtag);
+       return 0;
+}
+
+static void p9srv_flush(struct p9srv_req *req)
+{
+       p9_create_rflush(req->rcall);
+       p9srv_respond(req, req->rcall);
+}
+
+static void p9srv_walk(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid, *nfid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.twalk.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+
+       req->fid = fid;
+       if (!(fid->type & P9_QTDIR) && tc->params.twalk.nwname > 0) {
+               p9srv_respond_error(req, Enotdir, ENOTDIR);
+               return;
+       }
+
+       if (fid->omode != (u16) ~0) {
+               p9srv_respond_error(req, Ebadusefid, EIO);
+               return;
+       }
+
+       if (tc->params.twalk.nwname > P9_MAXWELEM) {
+               p9srv_respond_error(req, Etoomanywnames, EIO);
+               return;
+       }
+
+       if (tc->params.twalk.newfid != tc->params.twalk.fid) {
+               nfid = p9srv_fid_create(conn->fidpool, tc->params.twalk.newfid);
+               if (IS_ERR(nfid)) {
+                       p9srv_respond_error(req, Ebadusefid, PTR_ERR(nfid));
+                       return;
+               }
+               nfid->conn = req->conn;
+               nfid->uid = fid->uid;
+               nfid->type = fid->type;
+       } else {
+               nfid = fid;
+               p9srv_fid_incref(fid);
+       }
+       req->newfid = nfid;
+
+       if (srv->walk)
+               (*srv->walk)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_walk_post(struct p9srv_req *req)
+{
+       int n;
+       struct p9_fcall *rc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (req->rcall && req->rcall->id == P9_RWALK && req->newfid) {
+               rc = req->rcall;
+               n = rc->params.rwalk.nwqid;
+               if (n > 0)
+                       req->newfid->type = rc->params.rwalk.wqids[n - 1].type;
+
+               if (req->fid != req->newfid)
+                       p9srv_fid_incref(req->newfid);
+       }
+}
+
+static void p9srv_open(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       fid = p9srv_fid_find(conn->fidpool, tc->params.topen.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if (fid->omode != (u16) ~0) {
+               p9srv_respond_error(req, Ebadusefid, EIO);
+               return;
+       }
+
+       if (fid->type & P9_QTDIR && tc->params.topen.mode != P9_OREAD) {
+               p9srv_respond_error(req, Eperm, EPERM);
+               return;
+       }
+
+       if (srv->open)
+               (*srv->open)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_open_post(struct p9srv_req *req)
+{
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (req->rcall && req->rcall->id == P9_ROPEN && req->fid)
+               req->fid->omode = req->tcall->params.topen.mode;
+}
+
+static void p9srv_create(struct p9srv_req *req)
+{
+       int perm;
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.tcreate.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if (fid->omode != (u16) ~0) {
+               p9srv_respond_error(req, Ebadusefid, EIO);
+               return;
+       }
+
+       if (!(fid->type & P9_QTDIR)) {
+               p9srv_respond_error(req, Enotdir, ENOTDIR);
+               return;
+       }
+
+       perm = tc->params.tcreate.perm;
+       if ((perm & P9_DMDIR) && (tc->params.tcreate.mode != P9_OREAD)) {
+               p9srv_respond_error(req, Eperm, EPERM);
+               return;
+       }
+
+       if (perm & (P9_DMNAMEDPIPE | P9_DMSYMLINK | P9_DMLINK | P9_DMDEVICE |
+               P9_DMSOCKET) && !conn->dotu) {
+
+               p9srv_respond_error(req, Eperm, EPERM);
+               return;
+       }
+
+       if (srv->create)
+               (*srv->create)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_create_post(struct p9srv_req *req)
+{
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (req->rcall && req->rcall->id == P9_RCREATE && req->fid) {
+               req->fid->omode = req->tcall->params.tcreate.mode;
+               req->fid->type = req->rcall->params.rcreate.qid.type;
+       }
+}
+
+static void p9srv_read(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.tread.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if ((fid->omode == (u16) ~0) || ((fid->omode & 3) == P9_OWRITE)) {
+               p9srv_respond_error(req, Ebadusefid, EIO);
+               return;
+       }
+
+       if (fid->type & P9_QTDIR && tc->params.tread.offset != 0 &&
+                               tc->params.tread.offset != fid->diroffset) {
+               p9srv_respond_error(req, Ebadoffset, EIO);
+               return;
+       }
+
+       if (tc->params.tread.count + P9_IOHDRSZ > conn->msize) {
+               p9srv_respond_error(req, Etoolarge, EIO);
+               return;
+       }
+
+       if (srv->read)
+               (*srv->read)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_read_post(struct p9srv_req *req)
+{
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (req->fid && req->rcall && req->rcall->id == P9_RREAD &&
+                                       req->fid->type & P9_QTDIR)
+               req->fid->diroffset = req->tcall->params.tread.offset +
+                       req->rcall->params.rread.count;
+}
+
+static void p9srv_write(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.twrite.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if ((fid->omode == (u16) ~0) || ((fid->omode & 3) == P9_OREAD)) {
+               p9srv_respond_error(req, Ebadusefid, EIO);
+               return;
+       }
+
+       if (tc->params.twrite.count + P9_IOHDRSZ > conn->msize) {
+               p9srv_respond_error(req, Etoolarge, EIO);
+               return;
+       }
+
+       if (srv->write)
+               (*srv->write)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_clunk(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.tclunk.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if (srv->clunk)
+               (*srv->clunk)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_clunk_post(struct p9srv_req *req)
+{
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       if (req->rcall && req->rcall->id == P9_RCLUNK && req->fid)
+               p9srv_fid_decref(req->fid);
+}
+
+static void p9srv_remove(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.tclunk.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if (srv->remove)
+               (*srv->remove)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_remove_post(struct p9srv_req *req)
+{
+       /* we need to clunk the fid no matter error or not */
+       if (req->fid)
+               p9srv_fid_decref(req->fid);
+}
+
+static void p9srv_stat(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.tstat.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if (srv->stat)
+               (*srv->stat)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+static void p9srv_wstat(struct p9srv_req *req)
+{
+       struct p9srv *srv;
+       struct p9srv_conn *conn;
+       struct p9srv_fid *fid;
+       struct p9_fcall *tc;
+       struct p9_stat *stat;
+
+       P9_DPRINTK(P9SRV_DEBUG_FCALL, "req %p\n", req);
+       conn = req->conn;
+       srv = conn->srv;
+       tc = req->tcall;
+       stat = &tc->params.twstat.stat;
+       fid = p9srv_fid_find(conn->fidpool, tc->params.twstat.fid);
+       if (IS_ERR(fid)) {
+               p9srv_respond_error(req, Eunknownfid, PTR_ERR(fid));
+               return;
+       }
+       req->fid = fid;
+
+       if ((stat->type != (u16) ~0) || (stat->dev != (u32) ~0) ||
+                               (stat->qid.version != (u32) ~0) ||
+                               (stat->qid.path != (u64) ~0)) {
+               p9srv_respond_error(req, Eperm, EPERM);
+               return;
+       }
+
+       if (stat->mode != (u32) ~0 && ((fid->type & P9_QTDIR &&
+               !(stat->mode & P9_DMDIR)) ||
+               (!(fid->type & P9_QTDIR) && (stat->mode & P9_DMDIR)))) {
+
+               p9srv_respond_error(req, Edirchange, EPERM);
+               return;
+       }
+
+       if (srv->wstat)
+               (*srv->wstat)(req);
+       else
+               p9srv_respond_error(req, Enotimpl, EIO);
+}
+
+struct p9srv_fidpool *p9srv_fidpool_create(void)
+{
+       int i;
+       struct p9srv_fidpool *fp;
+
+       fp = kmalloc(sizeof(struct p9srv_fidpool), GFP_KERNEL);
+       if (!fp)
+               return ERR_PTR(-ENOMEM);
+
+       spin_lock_init(&fp->lock);
+       for (i = 0; i < FID_HTABLE_SIZE; i++)
+               INIT_HLIST_HEAD(&fp->hash[i]);
+
+       P9_DPRINTK(P9SRV_DEBUG_FID, "fidpool %p\n", fp);
+       return fp;
+}
+
+void p9srv_fidpool_destroy(struct p9srv_fidpool *fp)
+{
+       int i;
+
+       P9_DPRINTK(P9SRV_DEBUG_FID, "fidpool %p\n", fp);
+       for (i = 0; i < FID_HTABLE_SIZE; i++)
+               BUG_ON(!hlist_empty(&fp->hash[i]));
+
+       kfree(fp);
+}
+
+void p9srv_fidpool_reset(struct p9srv_fidpool *fp)
+{
+       int i;
+       struct p9srv_fid *cfid;
+       struct hlist_node *hn, *htmp;
+       HLIST_HEAD(hh);
+
+       P9_DPRINTK(P9SRV_DEBUG_FID, "fidpool %p\n", fp);
+       spin_lock(&fp->lock);
+       for (i = 0; i < FID_HTABLE_SIZE; i++) {
+               hlist_for_each_entry_safe(cfid, hn, htmp, &fp->hash[i],
+                                                               fid_list) {
+                       hlist_del(hn);
+                       hlist_add_head(hn, &hh);
+               }
+       }
+       spin_unlock(&fp->lock);
+
+       hlist_for_each_entry_safe(cfid, hn, htmp, &hh, fid_list) {
+               atomic_set(&cfid->refcount, 1);
+               p9srv_fid_decref(cfid);
+       }
+}
+
+struct p9srv_fid *p9srv_fid_create(struct p9srv_fidpool *fp, u32 fid)
+{
+       unsigned long hash;
+       struct p9srv_fid *cfid, *nfid;
+       struct hlist_node *hn;
+
+       P9_DPRINTK(P9SRV_DEBUG_FID, "fidpool %p fid %d\n", fp, fid);
+       hash = hash_long(fid, FID_HTABLE_BITS);
+       nfid = kmalloc(sizeof(struct p9srv_fid), GFP_KERNEL);
+       if (!nfid)
+               return ERR_PTR(-ENOMEM);
+
+       nfid->fid = fid;
+       atomic_set(&nfid->refcount, 0);
+       nfid->conn = NULL;
+       nfid->aux = NULL;
+       nfid->omode = ~0;
+       nfid->type = 0;
+       nfid->diroffset = 0;
+       nfid->uid = ~0;
+       nfid->fidpool = fp;
+       INIT_HLIST_NODE(&nfid->fid_list);
+       spin_lock(&fp->lock);
+       hlist_for_each_entry(cfid, hn, &fp->hash[hash], fid_list) {
+               if (cfid->fid == fid) {
+                       spin_unlock(&fp->lock);
+                       kfree(nfid);
+                       return ERR_PTR(-EEXIST);
+               }
+       }
+
+       hlist_add_head(&nfid->fid_list, &fp->hash[hash]);
+       spin_unlock(&fp->lock);
+       p9srv_fid_incref(nfid);
+       return nfid;
+}
+
+struct p9srv_fid *p9srv_fid_find(struct p9srv_fidpool *fp, u32 fid)
+{
+       unsigned long hash;
+       struct p9srv_fid *cfid;
+       struct hlist_node *hn;
+
+       hash = hash_long(fid, FID_HTABLE_BITS);
+       spin_lock(&fp->lock);
+       hlist_for_each_entry(cfid, hn, &fp->hash[hash], fid_list) {
+               if (cfid->fid == fid) {
+                       spin_unlock(&fp->lock);
+                       p9srv_fid_incref(cfid);
+                       return cfid;
+               }
+       }
+       spin_unlock(&fp->lock);
+
+       return NULL;
+}
+EXPORT_SYMBOL(p9srv_fid_find);
+
+void p9srv_fid_incref(struct p9srv_fid *fid)
+{
+       if (fid)
+               atomic_inc(&fid->refcount);
+
+       P9_DPRINTK(P9SRV_DEBUG_FID, "fidpool %p fid %d count %d\n",
+               fid->fidpool, fid->fid, atomic_read(&fid->refcount));
+}
+EXPORT_SYMBOL(p9srv_fid_incref);
+
+void p9srv_fid_decref(struct p9srv_fid *fid)
+{
+       int n;
+
+       if (!fid)
+               return;
+
+       n = atomic_dec_and_test(&fid->refcount);
+       P9_DPRINTK(P9SRV_DEBUG_FID, "fidpool %p fid %d count %d \n",
+               fid->fidpool, fid->fid, atomic_read(&fid->refcount));
+       if (n) {
+               P9_DPRINTK(P9SRV_DEBUG_FID, "destroy fidpool %p fid %d\n",
+                       fid->fidpool, fid->fid);
+               spin_lock(&fid->fidpool->lock);
+               hlist_del(&fid->fid_list);
+               spin_unlock(&fid->fidpool->lock);
+               if (fid->conn && fid->conn->srv && fid->conn->srv->fiddestroy)
+                       (*fid->conn->srv->fiddestroy)(fid);
+               kfree(fid);
+       }
+}
+EXPORT_SYMBOL(p9srv_fid_decref);
+
+struct p9srv_conn *p9srv_conn_create(struct p9srv *srv,
+       struct p9_trans *trans)
+{
+       int err;
+       struct p9srv_conn *conn;
+
+       conn = kmalloc(sizeof(struct p9srv_conn), GFP_KERNEL);
+       if (!conn)
+               return ERR_PTR(-ENOMEM);
+
+       trans->aux = conn;
+       conn->srv = srv;
+       conn->trans = trans;
+       conn->msize = srv->msize;
+       conn->dotu = srv->dotu;
+       conn->status = 0;
+       INIT_LIST_HEAD(&conn->conn_list);
+       atomic_set(&conn->reset_wcount, 0);
+       init_waitqueue_head(&conn->reset_wqueue);
+       conn->fidpool = p9srv_fidpool_create();
+       if (!conn->fidpool) {
+               err = PTR_ERR(conn->fidpool);
+               kfree(conn);
+               return ERR_PTR(err);
+       }
+
+       spin_lock(&srv->lock);
+       list_add_tail(&conn->conn_list, &srv->conn_list);
+       spin_unlock(&srv->lock);
+
+       if (srv->connopen)
+               (*srv->connopen)(conn);
+
+       p9srv_srv_ref(conn->srv);
+       trans->request = p9srv_conn_request;
+       P9_DPRINTK(P9SRV_DEBUG_CONN, "conn %p\n", conn);
+       return conn;
+}
+EXPORT_SYMBOL(p9srv_conn_create);
+
+void p9srv_conn_destroy(struct p9srv_conn *conn)
+{
+       P9_DPRINTK(P9SRV_DEBUG_CONN, "start conn %p\n", conn);
+       if (!test_and_set_bit(Destroy, &conn->status))
+               p9srv_conn_reset(conn, NULL);
+
+       (*conn->trans->destroy)(conn->trans);
+       conn->trans = NULL;
+       list_del(&conn->conn_list);
+       if (conn->srv->connclose)
+               (*conn->srv->connclose)(conn);
+
+       p9srv_fidpool_destroy(conn->fidpool);
+       p9srv_srv_unref(conn->srv);
+       P9_DPRINTK(P9SRV_DEBUG_CONN, "end conn %p\n", conn);
+       kfree(conn);
+}
+EXPORT_SYMBOL(p9srv_conn_destroy);
+
+void p9srv_conn_reset(struct p9srv_conn *conn, struct p9srv_req *vreq)
+{
+       int i, n;
+       struct p9_str *version;
+       struct p9srv *srv;
+       struct p9srv_req *req, *rptr;
+       struct p9srv_req *wreqs[16];
+       LIST_HEAD(req_list);
+
+       P9_DPRINTK(P9SRV_DEBUG_CONN, "conn %p\n", conn);
+       srv = conn->srv;
+       if (test_and_set_bit(Reset, &conn->status))
+               return;
+
+       atomic_set(&conn->reset_wcount, 0);
+       spin_lock(&srv->lock);
+       /* remove all requests the server didn't work on yet */
+       list_for_each_entry_safe(req, rptr, &srv->req_list, req_list) {
+               if (req->conn == conn)
+                       list_move(&req->req_list, &req_list);
+       }
+
+again:
+       /* flush the work requests (ARRAY_SIZE(wreqs) at a time) */
+       n = 0;
+       list_for_each_entry(req, &srv->workreq_list, req_list) {
+               if (req->conn == conn && req != vreq &&
+                       !test_and_set_bit(Flush, &req->status)) {
+
+                       wreqs[n++] = req;
+                       p9srv_req_ref(req);
+                       if (n >= ARRAY_SIZE(wreqs))
+                               break;
+               }
+       }
+       spin_unlock(&srv->lock);
+
+       atomic_add(n, &conn->reset_wcount);
+       for (i = 0; i < n; i++) {
+               if (srv->flush)
+                       if ((*srv->flush)(wreqs[i]))
+                               p9srv_respond(wreqs[i], NULL);
+
+               p9srv_req_unref(req);
+       }
+
+       if (n >= ARRAY_SIZE(wreqs)) {
+               spin_lock(&srv->lock);
+               goto again;
+       }
+
+       list_for_each_entry_safe(req, rptr, &req_list, req_list) {
+               list_del(&req_list);
+               p9srv_req_unref(req);
+       }
+
+       /* wait for all workreqs to finish */
+       wait_event_interruptible(conn->reset_wqueue,
+               !atomic_read(&conn->reset_wcount));
+       p9srv_fidpool_reset(conn->fidpool);
+       if (vreq) {
+               conn->msize = vreq->tcall->params.tversion.msize;
+               if (srv->msize < conn->msize)
+                       conn->msize = srv->msize;
+
+               conn->dotu = srv->dotu;
+               version = &vreq->tcall->params.tversion.version;
+               if (version->len != 8 || memcmp(version->str, "9P2000.u", 8) != 
0)
+                       conn->dotu = 0;
+       }
+
+       clear_bit(Reset, &conn->status);
+}
+
+static void p9srv_conn_request(struct p9_trans *trans, struct p9_trans_req 
*treq)
+{
+       struct p9srv_conn *conn;
+       struct p9srv_req *req;
+
+       conn = trans->aux;
+       if (trans->err) {
+               P9_DPRINTK(P9SRV_DEBUG_CONN, "transport error %d\n", 
trans->err);
+               p9srv_conn_destroy(conn);
+               return;
+       }
+
+#ifdef CONFIG_NET_9P_DEBUG
+       if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
+               char buf[150];
+
+               p9_printfcall(buf, sizeof(buf), treq->tc, conn->dotu);
+               printk(KERN_NOTICE ">}> %s\n", buf);
+       }
+#endif
+
+       req = p9srv_req_create();
+       req->conn = conn;
+       req->tag = treq->tag;
+       req->tcall = treq->tc;
+       req->rcall = treq->rc;
+       if (!req->rcall)
+               req->rcall = p9_fcall_alloc(conn->msize);
+
+       req->tag = treq->tag;
+       req->req = treq;
+       spin_lock(&conn->srv->lock);
+       list_add_tail(&req->req_list, &conn->srv->req_list);
+       spin_unlock(&conn->srv->lock);
+       if (req->tcall->id != P9_TFLUSH || !p9srv_flush_req(req))
+               queue_work(p9srv_wq, &req->pq);
+}
+
+void p9srv_conn_respond(struct p9srv_req *req)
+{
+       struct p9_trans_req *treq;
+
+       treq = req->req;
+       if (treq->rc != req->rcall) {
+               kfree(treq->rc);
+               treq->rc = req->rcall;
+       }
+
+#ifdef CONFIG_NET_9P_DEBUG
+       if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
+               char buf[150];
+
+               p9_printfcall(buf, sizeof(buf), treq->rc, req->conn->dotu);
+               printk(KERN_NOTICE "<{< %s\n", buf);
+       }
+#endif
+
+       (*treq->cb)(req->conn->trans, treq);
+       p9srv_req_unref(req);
+}
+
+static int __init p9srv_init(void)
+{
+       p9srv_wq = create_workqueue("9psrv");
+       if (!p9srv_wq) {
+               printk(KERN_WARNING "9psrv: creating workqueue failed\n");
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
+static void __exit p9srv_exit(void)
+{
+       destroy_workqueue(p9srv_wq);
+       p9srv_wq = NULL;
+}
+
+module_init(p9srv_init)
+module_exit(p9srv_exit)
+
+MODULE_AUTHOR("Latchesar Ionkov <[EMAIL PROTECTED]>");
+MODULE_LICENSE("GPL");
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