9p: fix error path during early mount

There was some cleanup issues during early mount which would trigger
a kernel bug for certain types of failure.  This patch reorganizes the
cleanup to get rid of the bad behavior.

This also merges the 9pnet and 9pnet_fd modules for the purpose of
configuration and initialization.  Keeping the fd transport separate
from the core 9pnet code seemed like a good idea at the time, but in
practice has caused more harm and confusion than good.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

fs/9p/v9fs.c

@@ -206,12 +206,14 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	v9ses->uid = ~0;
 	v9ses->dfltuid = V9FS_DEFUID;
 	v9ses->dfltgid = V9FS_DEFGID;
-	v9ses->options = kstrdup(data, GFP_KERNEL);
-	if (!v9ses->options) {
-		P9_DPRINTK(P9_DEBUG_ERROR,
+	if (data) {
+		v9ses->options = kstrdup(data, GFP_KERNEL);
+		if (!v9ses->options) {
+			P9_DPRINTK(P9_DEBUG_ERROR,
 			   "failed to allocate copy of option string\n");
-		retval = -ENOMEM;
-		goto error;
+			retval = -ENOMEM;
+			goto error;
+		}
 	}
 
 	rc = v9fs_parse_options(v9ses);
@@ -260,7 +262,6 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	return fid;
 
 error:
-	v9fs_session_close(v9ses);
 	return ERR_PTR(retval);
 }
 

fs/9p/vfs_super.c

@@ -128,29 +128,26 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 	fid = v9fs_session_init(v9ses, dev_name, data);
 	if (IS_ERR(fid)) {
 		retval = PTR_ERR(fid);
-		fid = NULL;
-		kfree(v9ses);
-		v9ses = NULL;
-		goto error;
+		goto close_session;
 	}
 
 	st = p9_client_stat(fid);
 	if (IS_ERR(st)) {
 		retval = PTR_ERR(st);
-		goto error;
+		goto clunk_fid;
 	}
 
 	sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 	if (IS_ERR(sb)) {
 		retval = PTR_ERR(sb);
-		goto error;
+		goto free_stat;
 	}
 	v9fs_fill_super(sb, v9ses, flags);
 
 	inode = v9fs_get_inode(sb, S_IFDIR | mode);
 	if (IS_ERR(inode)) {
 		retval = PTR_ERR(inode);
-		goto error;
+		goto release_sb;
 	}
 
 	inode->i_uid = uid;
@@ -159,7 +156,7 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 	root = d_alloc_root(inode);
 	if (!root) {
 		retval = -ENOMEM;
-		goto error;
+		goto release_sb;
 	}
 
 	sb->s_root = root;
@@ -170,21 +167,22 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 
 	return simple_set_mnt(mnt, sb);
 
-error:
-	kfree(st);
-	if (fid)
-		p9_client_clunk(fid);
-
-	if (v9ses) {
-		v9fs_session_close(v9ses);
-		kfree(v9ses);
-	}
-
+release_sb:
 	if (sb) {
 		up_write(&sb->s_umount);
 		deactivate_super(sb);
 	}
 
+free_stat:
+	kfree(st);
+
+clunk_fid:
+	p9_client_clunk(fid);
+
+close_session:
+	v9fs_session_close(v9ses);
+	kfree(v9ses);
+
 	return retval;
 }
 

include/net/9p/9p.h

@@ -595,4 +595,5 @@ int p9_idpool_check(int id, struct p9_idpool *p);
 
 int p9_error_init(void);
 int p9_errstr2errno(char *, int);
+int p9_trans_fd_init(void);
 #endif /* NET_9P_H */

include/net/9p/transport.h

@@ -96,5 +96,4 @@ struct p9_trans_module {
 void v9fs_register_trans(struct p9_trans_module *m);
 struct p9_trans_module *v9fs_match_trans(const substring_t *name);
 struct p9_trans_module *v9fs_default_trans(void);
-
 #endif /* NET_9P_TRANSPORT_H */

net/9p/Kconfig

@@ -13,16 +13,6 @@ menuconfig NET_9P
 
 	  If unsure, say N.
 
-config NET_9P_FD
-	depends on NET_9P
-	default y if NET_9P
-	tristate "9P File Descriptor Transports (Experimental)"
-	help
-	  This builds support for file descriptor transports for 9p
-	  which includes support for TCP/IP, named pipes, or passed
-	  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_VIRTIO
 	depends on NET_9P && EXPERIMENTAL && VIRTIO
 	tristate "9P Virtio Transport (Experimental)"

net/9p/Makefile

 obj-$(CONFIG_NET_9P) := 9pnet.o
-obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
 obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 
 9pnet-objs := \
@@ -9,8 +8,6 @@ obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 	error.o \
 	fcprint.o \
 	util.o \
-
-9pnet_fd-objs := \
 	trans_fd.o \
 
 9pnet_virtio-objs := \

net/9p/mod.c

@@ -107,6 +107,7 @@ static int __init init_p9(void)
 
 	p9_error_init();
 	printk(KERN_INFO "Installing 9P2000 support\n");
+	p9_trans_fd_init();
 
 	return ret;
 }

net/9p/trans_fd.c

@@ -1433,6 +1433,23 @@ static void p9_fd_close(struct p9_trans *trans)
 	kfree(ts);
 }
 
+/*
+ * stolen from NFS - maybe should be made a generic function?
+ */
+static inline int valid_ipaddr4(const char *buf)
+{
+	int rc, count, in[4];
+
+	rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
+	if (rc != 4)
+		return -EINVAL;
+	for (count = 0; count < 4; count++) {
+		if (in[count] > 255)
+			return -EINVAL;
+	}
+	return 0;
+}
+
 static struct p9_trans *
 p9_trans_create_tcp(const char *addr, char *args, int msize, unsigned char dotu)
 {
@@ -1447,6 +1464,9 @@ p9_trans_create_tcp(const char *addr, char *args, int msize, unsigned char dotu)
 	if (err < 0)
 		return ERR_PTR(err);
 
+	if (valid_ipaddr4(addr) < 0)
+		return ERR_PTR(-EINVAL);
+
 	csocket = NULL;
 	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
 	if (!trans)
@@ -1625,7 +1645,7 @@ static struct p9_trans_module p9_fd_trans = {
 	.create = p9_trans_create_fd,
 };
 
-static int __init p9_trans_fd_init(void)
+int p9_trans_fd_init(void)
 {
 	int ret = p9_mux_global_init();
 	if (ret) {
@@ -1639,9 +1659,4 @@ static int __init p9_trans_fd_init(void)
 
 	return 0;
 }
-
-module_init(p9_trans_fd_init);
-
-MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
-MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
-MODULE_LICENSE("GPL");
+EXPORT_SYMBOL(p9_trans_fd_init);