Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: saving negative to unsigned char
  9p: return on mutex_lock_interruptible()
  9p: Creating files with names too long should fail with ENAMETOOLONG.
  9p: Make sure we are able to clunk the cached fid on umount
  9p: drop nlink remove
  fs/9p: Clunk the fid resulting from partial walk of the name
  9p: documentation update
  9p: Fix setting of protocol flags in v9fs_session_info structure.

Documentation/filesystems/9p.txt

@@ -37,6 +37,15 @@ For Plan 9 From User Space applications (http://swtch.com/plan9)
 
 	mount -t 9p `namespace`/acme /mnt/9 -o trans=unix,uname=$USER
 
+For server running on QEMU host with virtio transport:
+
+	mount -t 9p -o trans=virtio <mount_tag> /mnt/9
+
+where mount_tag is the tag associated by the server to each of the exported
+mount points. Each 9P export is seen by the client as a virtio device with an
+associated "mount_tag" property. Available mount tags can be
+seen by reading /sys/bus/virtio/drivers/9pnet_virtio/virtio<n>/mount_tag files.
+
 OPTIONS
 =======
 
@@ -47,7 +56,7 @@ OPTIONS
 			fd   	- used passed file descriptors for connection
                                 (see rfdno and wfdno)
 			virtio	- connect to the next virtio channel available
-				(from lguest or KVM with trans_virtio module)
+				(from QEMU with trans_virtio module)
 			rdma	- connect to a specified RDMA channel
 
   uname=name	user name to attempt mount as on the remote server.  The
@@ -85,7 +94,12 @@ OPTIONS
 
   port=n	port to connect to on the remote server
 
-  noextend	force legacy mode (no 9p2000.u semantics)
+  noextend	force legacy mode (no 9p2000.u or 9p2000.L semantics)
+
+  version=name	Select 9P protocol version. Valid options are:
+			9p2000          - Legacy mode (same as noextend)
+			9p2000.u        - Use 9P2000.u protocol
+			9p2000.L        - Use 9P2000.L protocol
 
   dfltuid	attempt to mount as a particular uid
 

fs/9p/fid.c

@@ -111,7 +111,7 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
 {
 	int i, n, l, clone, any, access;
 	u32 uid;
-	struct p9_fid *fid;
+	struct p9_fid *fid, *old_fid = NULL;
 	struct dentry *d, *ds;
 	struct v9fs_session_info *v9ses;
 	char **wnames, *uname;
@@ -184,10 +184,18 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
 		l = min(n - i, P9_MAXWELEM);
 		fid = p9_client_walk(fid, l, &wnames[i], clone);
 		if (IS_ERR(fid)) {
+			if (old_fid) {
+				/*
+				 * If we fail, clunk fid which are mapping
+				 * to path component and not the last component
+				 * of the path.
+				 */
+				p9_client_clunk(old_fid);
+			}
 			kfree(wnames);
 			return fid;
 		}
-
+		old_fid = fid;
 		i += l;
 		clone = 0;
 	}

fs/9p/v9fs.c

@@ -242,7 +242,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	list_add(&v9ses->slist, &v9fs_sessionlist);
 	spin_unlock(&v9fs_sessionlist_lock);
 
-	v9ses->flags = V9FS_PROTO_2000U | V9FS_ACCESS_USER;
+	v9ses->flags = V9FS_ACCESS_USER;
 	strcpy(v9ses->uname, V9FS_DEFUSER);
 	strcpy(v9ses->aname, V9FS_DEFANAME);
 	v9ses->uid = ~0;
@@ -263,8 +263,10 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 		goto error;
 	}
 
-	if (!p9_is_proto_dotu(v9ses->clnt))
-		v9ses->flags &= ~V9FS_PROTO_2000U;
+	if (p9_is_proto_dotl(v9ses->clnt))
+		v9ses->flags |= V9FS_PROTO_2000L;
+	else if (p9_is_proto_dotu(v9ses->clnt))
+		v9ses->flags |= V9FS_PROTO_2000U;
 
 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 
@@ -341,6 +343,19 @@ void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 	p9_client_disconnect(v9ses->clnt);
 }
 
+/**
+ * v9fs_session_begin_cancel - Begin terminate of a session
+ * @v9ses: session to terminate
+ *
+ * After this call we don't allow any request other than clunk.
+ */
+
+void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
+{
+	P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
+	p9_client_begin_disconnect(v9ses->clnt);
+}
+
 extern int v9fs_error_init(void);
 
 static struct kobject *v9fs_kobj;

fs/9p/v9fs.h

@@ -108,6 +108,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
 									char *);
 void v9fs_session_close(struct v9fs_session_info *v9ses);
 void v9fs_session_cancel(struct v9fs_session_info *v9ses);
+void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
 
 #define V9FS_MAGIC 0x01021997
 

fs/9p/vfs_dir.c

@@ -131,6 +131,8 @@ static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 	rdir = (struct p9_rdir *) fid->rdir;
 
 	err = mutex_lock_interruptible(&rdir->mutex);
+	if (err)
+		return err;
 	while (err == 0) {
 		if (rdir->tail == rdir->head) {
 			err = v9fs_file_readn(filp, rdir->buf, NULL,

fs/9p/vfs_inode.c

@@ -432,6 +432,7 @@ v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 
 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 {
+	int retval;
 	struct inode *file_inode;
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *v9fid;
@@ -445,7 +446,10 @@ static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 	if (IS_ERR(v9fid))
 		return PTR_ERR(v9fid);
 
-	return p9_client_remove(v9fid);
+	retval = p9_client_remove(v9fid);
+	if (!retval)
+		drop_nlink(file_inode);
+	return retval;
 }
 
 static int
@@ -657,6 +661,9 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 		dir, dentry->d_name.name, dentry, nameidata);
 
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
 	sb = dir->i_sb;
 	v9ses = v9fs_inode2v9ses(dir);
 	dfid = v9fs_fid_lookup(dentry->d_parent);

fs/9p/vfs_super.c

@@ -194,6 +194,7 @@ static void v9fs_kill_super(struct super_block *s)
 
 	kill_anon_super(s);
 
+	v9fs_session_cancel(v9ses);
 	v9fs_session_close(v9ses);
 	kfree(v9ses);
 	s->s_fs_info = NULL;
@@ -206,7 +207,7 @@ v9fs_umount_begin(struct super_block *sb)
 	struct v9fs_session_info *v9ses;
 
 	v9ses = sb->s_fs_info;
-	v9fs_session_cancel(v9ses);
+	v9fs_session_begin_cancel(v9ses);
 }
 
 static const struct super_operations v9fs_super_ops = {

include/net/9p/client.h

@@ -54,6 +54,7 @@ enum p9_proto_versions{
 
 enum p9_trans_status {
 	Connected,
+	BeginDisconnect,
 	Disconnected,
 	Hung,
 };
@@ -198,6 +199,7 @@ int p9_client_version(struct p9_client *);
 struct p9_client *p9_client_create(const char *dev_name, char *options);
 void p9_client_destroy(struct p9_client *clnt);
 void p9_client_disconnect(struct p9_client *clnt);
+void p9_client_begin_disconnect(struct p9_client *clnt);
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 					char *uname, u32 n_uname, char *aname);
 struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,

net/9p/client.c

@@ -72,9 +72,10 @@ inline int p9_is_proto_dotu(struct p9_client *clnt)
 EXPORT_SYMBOL(p9_is_proto_dotu);
 
 /* Interpret mount option for protocol version */
-static unsigned char get_protocol_version(const substring_t *name)
+static int get_protocol_version(const substring_t *name)
 {
-	unsigned char version = -EINVAL;
+	int version = -EINVAL;
+
 	if (!strncmp("9p2000", name->from, name->to-name->from)) {
 		version = p9_proto_legacy;
 		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: Legacy\n");
@@ -534,7 +535,12 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 
 	P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
 
-	if (c->status != Connected)
+	/* we allow for any status other than disconnected */
+	if (c->status == Disconnected)
+		return ERR_PTR(-EIO);
+
+	/* if status is begin_disconnected we allow only clunk request */
+	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
 		return ERR_PTR(-EIO);
 
 	if (signal_pending(current)) {
@@ -800,8 +806,10 @@ void p9_client_destroy(struct p9_client *clnt)
 
 	v9fs_put_trans(clnt->trans_mod);
 
-	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
+	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
+		printk(KERN_INFO "Found fid %d not clunked\n", fid->fid);
 		p9_fid_destroy(fid);
+	}
 
 	if (clnt->fidpool)
 		p9_idpool_destroy(clnt->fidpool);
@@ -819,6 +827,13 @@ void p9_client_disconnect(struct p9_client *clnt)
 }
 EXPORT_SYMBOL(p9_client_disconnect);
 
+void p9_client_begin_disconnect(struct p9_client *clnt)
+{
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
+	clnt->status = BeginDisconnect;
+}
+EXPORT_SYMBOL(p9_client_begin_disconnect);
+
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 	char *uname, u32 n_uname, char *aname)
 {