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

* 'for-linus' of ssh://master.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: fix error path during early mount
  9p: make cryptic unknown error from server less scary
  9p: fix flags length in net
  9p: Correct fidpool creation failure in p9_client_create
  9p: use struct mutex instead of struct semaphore
  9p: propagate parse_option changes to client and transports
  fs/9p/v9fs.c (v9fs_parse_options): Handle kstrdup and match_strdup failure.
  9p: Documentation updates
  add match_strlcpy() us it to make v9fs make uname and remotename parsing more robust

23 files changed, 1014 insertions, 215 deletions

diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index 26e07df783b..c3bbd6af996 100644
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -22,6 +22,21 @@
 
 #include <linux/list.h>
 
+/**
+ * struct v9fs_dentry - 9p private data stored in dentry d_fsdata
+ * @lock: protects the fidlist
+ * @fidlist: list of FIDs currently associated with this dentry
+ *
+ * This structure defines the 9p private data associated with
+ * a particular dentry.  In particular, this private data is used
+ * to lookup which 9P FID handle should be used for a particular VFS
+ * operation.  FID handles are associated with dentries instead of
+ * inodes in order to more closely map functionality to the Plan 9
+ * expected behavior for FID reclaimation and tracking.
+ *
+ * See Also: Mapping FIDs to Linux VFS model in
+ * Design and Implementation of the Linux 9P File System documentation
+ */
 struct v9fs_dentry {
 	spinlock_t lock; /* protect fidlist */
 	struct list_head fidlist;
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 9b0f0222e8b..047c791427a 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -71,19 +71,19 @@ static match_table_t tokens = {
 
 /**
  * v9fs_parse_options - parse mount options into session structure
- * @options: options string passed from mount
  * @v9ses: existing v9fs session information
  *
+ * Return 0 upon success, -ERRNO upon failure.
  */
 
-static void v9fs_parse_options(struct v9fs_session_info *v9ses)
+static int v9fs_parse_options(struct v9fs_session_info *v9ses)
 {
 	char *options;
 	substring_t args[MAX_OPT_ARGS];
 	char *p;
 	int option = 0;
 	char *s, *e;
-	int ret;
+	int ret = 0;
 
 	/* setup defaults */
 	v9ses->afid = ~0;
@@ -91,19 +91,26 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 	v9ses->cache = 0;
 
 	if (!v9ses->options)
-		return;
+		return 0;
 
 	options = kstrdup(v9ses->options, GFP_KERNEL);
+	if (!options) {
+		P9_DPRINTK(P9_DEBUG_ERROR,
+			   "failed to allocate copy of option string\n");
+		return -ENOMEM;
+	}
+
 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;
 		if (!*p)
 			continue;
 		token = match_token(p, tokens, args);
 		if (token < Opt_uname) {
-			ret = match_int(&args[0], &option);
-			if (ret < 0) {
+			int r = match_int(&args[0], &option);
+			if (r < 0) {
 				P9_DPRINTK(P9_DEBUG_ERROR,
 					"integer field, but no integer?\n");
+				ret = r;
 				continue;
 			}
 		}
@@ -125,10 +132,10 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 			v9ses->afid = option;
 			break;
 		case Opt_uname:
-			match_strcpy(v9ses->uname, &args[0]);
+			match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 			break;
 		case Opt_remotename:
-			match_strcpy(v9ses->aname, &args[0]);
+			match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 			break;
 		case Opt_nodevmap:
 			v9ses->nodev = 1;
@@ -139,6 +146,13 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 
 		case Opt_access:
 			s = match_strdup(&args[0]);
+			if (!s) {
+				P9_DPRINTK(P9_DEBUG_ERROR,
+					   "failed to allocate copy"
+					   " of option argument\n");
+				ret = -ENOMEM;
+				break;
+			}
 			v9ses->flags &= ~V9FS_ACCESS_MASK;
 			if (strcmp(s, "user") == 0)
 				v9ses->flags |= V9FS_ACCESS_USER;
@@ -158,6 +172,7 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 		}
 	}
 	kfree(options);
+	return ret;
 }
 
 /**
@@ -173,6 +188,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 {
 	int retval = -EINVAL;
 	struct p9_fid *fid;
+	int rc;
 
 	v9ses->uname = __getname();
 	if (!v9ses->uname)
@@ -190,8 +206,21 @@ 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);
-	v9fs_parse_options(v9ses);
+	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;
+		}
+	}
+
+	rc = v9fs_parse_options(v9ses);
+	if (rc < 0) {
+		retval = rc;
+		goto error;
+	}
 
 	v9ses->clnt = p9_client_create(dev_name, v9ses->options);
 
@@ -233,7 +262,6 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	return fid;
 
 error:
-	v9fs_session_close(v9ses);
 	return ERR_PTR(retval);
 }
 
@@ -256,9 +284,12 @@ void v9fs_session_close(struct v9fs_session_info *v9ses)
 }
 
 /**
- * v9fs_session_cancel - mark transport as disconnected
- * 	and cancel all pending requests.
+ * v9fs_session_cancel - terminate a session
+ * @v9ses: session to terminate
+ *
+ * mark transport as disconnected and cancel all pending requests.
  */
+
 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 	p9_client_disconnect(v9ses->clnt);
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 7d3a1018db5..a7d56719299 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -21,18 +21,69 @@
  *
  */
 
-/*
-  * Session structure provides information for an opened session
-  *
-  */
+/**
+ * enum p9_session_flags - option flags for each 9P session
+ * @V9FS_EXTENDED: whether or not to use 9P2000.u extensions
+ * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
+ * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
+ * @V9FS_ACCESS_ANY: use a single attach for all users
+ * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
+ *
+ * Session flags reflect options selected by users at mount time
+ */
+enum p9_session_flags {
+	V9FS_EXTENDED		= 0x01,
+	V9FS_ACCESS_SINGLE	= 0x02,
+	V9FS_ACCESS_USER	= 0x04,
+	V9FS_ACCESS_ANY		= 0x06,
+	V9FS_ACCESS_MASK	= 0x06,
+};
+
+/* possible values of ->cache */
+/**
+ * enum p9_cache_modes - user specified cache preferences
+ * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
+ * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
+ *
+ * eventually support loose, tight, time, session, default always none
+ */
+
+enum p9_cache_modes {
+	CACHE_NONE,
+	CACHE_LOOSE,
+};
+
+/**
+ * struct v9fs_session_info - per-instance session information
+ * @flags: session options of type &p9_session_flags
+ * @nodev: set to 1 to disable device mapping
+ * @debug: debug level
+ * @afid: authentication handle
+ * @cache: cache mode of type &p9_cache_modes
+ * @options: copy of options string given by user
+ * @uname: string user name to mount hierarchy as
+ * @aname: mount specifier for remote hierarchy
+ * @maxdata: maximum data to be sent/recvd per protocol message
+ * @dfltuid: default numeric userid to mount hierarchy as
+ * @dfltgid: default numeric groupid to mount hierarchy as
+ * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
+ * @clnt: reference to 9P network client instantiated for this session
+ * @debugfs_dir: reference to debugfs_dir which can be used for add'l debug
+ *
+ * This structure holds state for each session instance established during
+ * a sys_mount() .
+ *
+ * Bugs: there seems to be a lot of state which could be condensed and/or
+ * removed.
+ */
 
 struct v9fs_session_info {
 	/* options */
-	unsigned char flags;	/* session flags */
-	unsigned char nodev;	/* set to 1 if no disable device mapping */
-	unsigned short debug;	/* debug level */
-	unsigned int afid;	/* authentication fid */
-	unsigned int cache;	/* cache mode */
+	unsigned char flags;
+	unsigned char nodev;
+	unsigned short debug;
+	unsigned int afid;
+	unsigned int cache;
 
 	char *options;		/* copy of mount options */
 	char *uname;		/* user name to mount as */
@@ -45,22 +96,6 @@ struct v9fs_session_info {
 	struct dentry *debugfs_dir;
 };
 
-/* session flags */
-enum {
-	V9FS_EXTENDED		= 0x01,	/* 9P2000.u */
-	V9FS_ACCESS_MASK	= 0x06,	/* access mask */
-	V9FS_ACCESS_SINGLE	= 0x02,	/* only one user can access the files */
-	V9FS_ACCESS_USER	= 0x04,	/* attache per user */
-	V9FS_ACCESS_ANY		= 0x06,	/* use the same attach for all users */
-};
-
-/* possible values of ->cache */
-/* eventually support loose, tight, time, session, default always none */
-enum {
-	CACHE_NONE,		/* default */
-	CACHE_LOOSE,		/* no consistency */
-};
-
 extern struct dentry *v9fs_debugfs_root;
 
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 6248f0e727a..97d3aed5798 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -43,7 +43,7 @@
 /**
  * v9fs_vfs_readpage - read an entire page in from 9P
  *
- * @file: file being read
+ * @filp: file being read
  * @page: structure to page
  *
  */
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 0924d4477da..88e3787c6ea 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -60,7 +60,7 @@ static inline int dt_type(struct p9_stat *mistat)
 
 /**
  * v9fs_dir_readdir - read a directory
- * @filep: opened file structure
+ * @filp: opened file structure
  * @dirent: directory structure ???
  * @filldir: function to populate directory structure ???
  *
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index a616fff8906..0d55affe37d 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -90,10 +90,11 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 
 /**
  * v9fs_file_lock - lock a file (or directory)
- * @inode: inode to be opened
- * @file: file being opened
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
  *
- * XXX - this looks like a local only lock, we should extend into 9P
+ * Bugs: this looks like a local only lock, we should extend into 9P
  *       by using open exclusive
  */
 
@@ -118,7 +119,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 
 /**
  * v9fs_file_read - read from a file
- * @filep: file pointer to read
+ * @filp: file pointer to read
  * @data: data buffer to read data into
  * @count: size of buffer
  * @offset: offset at which to read data
@@ -142,7 +143,7 @@ v9fs_file_read(struct file *filp, char __user * data, size_t count,
 
 /**
  * v9fs_file_write - write to a file
- * @filep: file pointer to write
+ * @filp: file pointer to write
  * @data: data buffer to write data from
  * @count: size of buffer
  * @offset: offset at which to write data
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 6a28842052e..40fa807bd92 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -129,6 +129,12 @@ static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
 	return res;
 }
 
+/**
+ * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
+ * @uflags: flags to convert
+ *
+ */
+
 int v9fs_uflags2omode(int uflags)
 {
 	int ret;
@@ -312,6 +318,14 @@ error:
 }
 */
 
+/**
+ * v9fs_inode_from_fid - populate an inode by issuing a attribute request
+ * @v9ses: session information
+ * @fid: fid to issue attribute request for
+ * @sb: superblock on which to create inode
+ *
+ */
+
 static struct inode *
 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 	struct super_block *sb)
@@ -384,9 +398,12 @@ v9fs_open_created(struct inode *inode, struct file *file)
 
 /**
  * v9fs_create - Create a file
+ * @v9ses: session information
+ * @dir: directory that dentry is being created in
  * @dentry:  dentry that is being created
  * @perm: create permissions
  * @mode: open mode
+ * @extension: 9p2000.u extension string to support devices, etc.
  *
  */
 static struct p9_fid *
@@ -461,7 +478,7 @@ error:
 
 /**
  * v9fs_vfs_create - VFS hook to create files
- * @inode: directory inode that is being created
+ * @dir: directory inode that is being created
  * @dentry:  dentry that is being deleted
  * @mode: create permissions
  * @nd: path information
@@ -519,7 +536,7 @@ error:
 
 /**
  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
- * @inode:  inode that is being unlinked
+ * @dir:  inode that is being unlinked
  * @dentry: dentry that is being unlinked
  * @mode: mode for new directory
  *
@@ -703,9 +720,9 @@ done:
 
 /**
  * v9fs_vfs_getattr - retrieve file metadata
- * @mnt - mount information
- * @dentry - file to get attributes on
- * @stat - metadata structure to populate
+ * @mnt: mount information
+ * @dentry: file to get attributes on
+ * @stat: metadata structure to populate
  *
  */
 
@@ -928,7 +945,7 @@ done:
 /**
  * v9fs_vfs_readlink - read a symlink's location
  * @dentry: dentry for symlink
- * @buf: buffer to load symlink location into
+ * @buffer: buffer to load symlink location into
  * @buflen: length of buffer
  *
  */
@@ -996,10 +1013,12 @@ static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
  * v9fs_vfs_put_link - release a symlink path
  * @dentry: dentry for symlink
  * @nd: nameidata
+ * @p: unused
  *
  */
 
-static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
+static void
+v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
 {
 	char *s = nd_get_link(nd);
 
@@ -1008,6 +1027,15 @@ static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void
 		__putname(s);
 }
 
+/**
+ * v9fs_vfs_mkspecial - create a special file
+ * @dir: inode to create special file in
+ * @dentry: dentry to create
+ * @mode: mode to create special file
+ * @extension: 9p2000.u format extension string representing special file
+ *
+ */
+
 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
 	int mode, const char *extension)
 {
@@ -1037,7 +1065,7 @@ static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
  * @dentry: dentry for symlink
  * @symname: symlink data
  *
- * See 9P2000.u RFC for more information
+ * See Also: 9P2000.u RFC for more information
  *
  */
 
@@ -1058,10 +1086,6 @@ v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
  *
  */
 
-/* XXX - lots of code dup'd from symlink and creates,
- * figure out a better reuse strategy
- */
-
 static int
 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
 	      struct dentry *dentry)
@@ -1098,7 +1122,7 @@ clunk_fid:
  * @dir: inode destination for new link
  * @dentry: dentry for file
  * @mode: mode for creation
- * @dev_t: device associated with special file
+ * @rdev: device associated with special file
  *
  */
 
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index a452ac67fc9..bf59c396049 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -75,6 +75,7 @@ static int v9fs_set_super(struct super_block *s, void *data)
  * v9fs_fill_super - populate superblock with info
  * @sb: superblock
  * @v9ses: session information
+ * @flags: flags propagated from v9fs_get_sb()
  *
  */
 
@@ -127,29 +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;
@@ -158,7 +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;
@@ -169,21 +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;
 }
 
diff --git a/include/linux/parser.h b/include/linux/parser.h
index 26b2bdfcaf0..7dcd0507575 100644
--- a/include/linux/parser.h
+++ b/include/linux/parser.h
@@ -29,5 +29,5 @@ int match_token(char *, match_table_t table, substring_t args[]);
 int match_int(substring_t *, int *result);
 int match_octal(substring_t *, int *result);
 int match_hex(substring_t *, int *result);
-void match_strcpy(char *, const substring_t *);
+size_t match_strlcpy(char *, const substring_t *, size_t);
 char *match_strdup(const substring_t *);
diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index 585eb449699..b3d3e27c629 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -29,14 +29,31 @@
 
 #ifdef CONFIG_NET_9P_DEBUG
 
-#define P9_DEBUG_ERROR		(1<<0)
-#define P9_DEBUG_9P	        (1<<2)
-#define P9_DEBUG_VFS	        (1<<3)
-#define P9_DEBUG_CONV		(1<<4)
-#define P9_DEBUG_MUX		(1<<5)
-#define P9_DEBUG_TRANS		(1<<6)
-#define P9_DEBUG_SLABS	      	(1<<7)
-#define P9_DEBUG_FCALL		(1<<8)
+/**
+ * enum p9_debug_flags - bits for mount time debug parameter
+ * @P9_DEBUG_ERROR: more verbose error messages including original error string
+ * @P9_DEBUG_9P: 9P protocol tracing
+ * @P9_DEBUG_VFS: VFS API tracing
+ * @P9_DEBUG_CONV: protocol conversion tracing
+ * @P9_DEBUG_MUX: trace management of concurrent transactions
+ * @P9_DEBUG_TRANS: transport tracing
+ * @P9_DEBUG_SLABS: memory management tracing
+ * @P9_DEBUG_FCALL: verbose dump of protocol messages
+ *
+ * These flags are passed at mount time to turn on various levels of
+ * verbosity and tracing which will be output to the system logs.
+ */
+
+enum p9_debug_flags {
+	P9_DEBUG_ERROR = 	(1<<0),
+	P9_DEBUG_9P = 		(1<<2),
+	P9_DEBUG_VFS =		(1<<3),
+	P9_DEBUG_CONV =		(1<<4),
+	P9_DEBUG_MUX =		(1<<5),
+	P9_DEBUG_TRANS =	(1<<6),
+	P9_DEBUG_SLABS =      	(1<<7),
+	P9_DEBUG_FCALL =	(1<<8),
+};
 
 extern unsigned int p9_debug_level;
 
@@ -62,9 +79,47 @@ do { \
 		format , __FUNCTION__, task_pid_nr(current), ## arg); \
 } while (0)
 
+/**
+ * enum p9_msg_t - 9P message types
+ * @P9_TVERSION: version handshake request
+ * @P9_RVERSION: version handshake response
+ * @P9_TAUTH: request to establish authentication channel
+ * @P9_RAUTH: response with authentication information
+ * @P9_TATTACH: establish user access to file service
+ * @P9_RATTACH: response with top level handle to file hierarchy
+ * @P9_TERROR: not used
+ * @P9_RERROR: response for any failed request
+ * @P9_TFLUSH: request to abort a previous request
+ * @P9_RFLUSH: response when previous request has been cancelled
+ * @P9_TWALK: descend a directory hierarchy
+ * @P9_RWALK: response with new handle for position within hierarchy
+ * @P9_TOPEN: prepare a handle for I/O on an existing file
+ * @P9_ROPEN: response with file access information
+ * @P9_TCREATE: prepare a handle for I/O on a new file
+ * @P9_RCREATE: response with file access information
+ * @P9_TREAD: request to transfer data from a file or directory
+ * @P9_RREAD: response with data requested
+ * @P9_TWRITE: reuqest to transfer data to a file
+ * @P9_RWRITE: response with out much data was transfered to file
+ * @P9_TCLUNK: forget about a handle to an entity within the file system
+ * @P9_RCLUNK: response when server has forgotten about the handle
+ * @P9_TREMOVE: request to remove an entity from the hierarchy
+ * @P9_RREMOVE: response when server has removed the entity
+ * @P9_TSTAT: request file entity attributes
+ * @P9_RSTAT: response with file entity attributes
+ * @P9_TWSTAT: request to update file entity attributes
+ * @P9_RWSTAT: response when file entity attributes are updated
+ *
+ * There are 14 basic operations in 9P2000, paired as
+ * requests and responses.  The one special case is ERROR
+ * as there is no @P9_TERROR request for clients to transmit to
+ * the server, but the server may respond to any other request
+ * with an @P9_RERROR.
+ *
+ * See Also: http://plan9.bell-labs.com/sys/man/5/INDEX.html
+ */
 
-/* Message Types */
-enum {
+enum p9_msg_t {
 	P9_TVERSION = 100,
 	P9_RVERSION,
 	P9_TAUTH = 102,
@@ -95,30 +150,71 @@ enum {
 	P9_RWSTAT,
 };
 
-/* open modes */
-enum {
+/**
+ * enum p9_open_mode_t - 9P open modes
+ * @P9_OREAD: open file for reading only
+ * @P9_OWRITE: open file for writing only
+ * @P9_ORDWR: open file for reading or writing
+ * @P9_OEXEC: open file for execution
+ * @P9_OTRUNC: truncate file to zero-length before opening it
+ * @P9_OREXEC: close the file when an exec(2) system call is made
+ * @P9_ORCLOSE: remove the file when the file is closed
+ * @P9_OAPPEND: open the file and seek to the end
+ * @P9_OEXCL: only create a file, do not open it
+ *
+ * 9P open modes differ slightly from Posix standard modes.
+ * In particular, there are extra modes which specify different
+ * semantic behaviors than may be available on standard Posix
+ * systems.  For example, @P9_OREXEC and @P9_ORCLOSE are modes that
+ * most likely will not be issued from the Linux VFS client, but may
+ * be supported by servers.
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/open
+ */
+
+enum p9_open_mode_t {
 	P9_OREAD = 0x00,
 	P9_OWRITE = 0x01,
 	P9_ORDWR = 0x02,
 	P9_OEXEC = 0x03,
-	P9_OEXCL = 0x04,
 	P9_OTRUNC = 0x10,
 	P9_OREXEC = 0x20,
 	P9_ORCLOSE = 0x40,
 	P9_OAPPEND = 0x80,
-};
-
-/* permissions */
-enum {
+	P9_OEXCL = 0x1000,
+};
+
+/**
+ * enum p9_perm_t - 9P permissions
+ * @P9_DMDIR: mode bite for directories
+ * @P9_DMAPPEND: mode bit for is append-only
+ * @P9_DMEXCL: mode bit for excluse use (only one open handle allowed)
+ * @P9_DMMOUNT: mode bite for mount points
+ * @P9_DMAUTH: mode bit for authentication file
+ * @P9_DMTMP: mode bit for non-backed-up files
+ * @P9_DMSYMLINK: mode bit for symbolic links (9P2000.u)
+ * @P9_DMLINK: mode bit for hard-link (9P2000.u)
+ * @P9_DMDEVICE: mode bit for device files (9P2000.u)
+ * @P9_DMNAMEDPIPE: mode bit for named pipe (9P2000.u)
+ * @P9_DMSOCKET: mode bit for socket (9P2000.u)
+ * @P9_DMSETUID: mode bit for setuid (9P2000.u)
+ * @P9_DMSETGID: mode bit for setgid (9P2000.u)
+ * @P9_DMSETVTX: mode bit for sticky bit (9P2000.u)
+ *
+ * 9P permissions differ slightly from Posix standard modes.
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+enum p9_perm_t {
 	P9_DMDIR = 0x80000000,
 	P9_DMAPPEND = 0x40000000,
 	P9_DMEXCL = 0x20000000,
 	P9_DMMOUNT = 0x10000000,
 	P9_DMAUTH = 0x08000000,
 	P9_DMTMP = 0x04000000,
+/* 9P2000.u extensions */
 	P9_DMSYMLINK = 0x02000000,
 	P9_DMLINK = 0x01000000,
-	/* 9P2000.u extensions */
 	P9_DMDEVICE = 0x00800000,
 	P9_DMNAMEDPIPE = 0x00200000,
 	P9_DMSOCKET = 0x00100000,
@@ -127,8 +223,26 @@ enum {
 	P9_DMSETVTX = 0x00010000,
 };
 
-/* qid.types */
-enum {
+/**
+ * enum p9_qid_t - QID types
+ * @P9_QTDIR: directory
+ * @P9_QTAPPEND: append-only
+ * @P9_QTEXCL: excluse use (only one open handle allowed)
+ * @P9_QTMOUNT: mount points
+ * @P9_QTAUTH: authentication file
+ * @P9_QTTMP: non-backed-up files
+ * @P9_QTSYMLINK: symbolic links (9P2000.u)
+ * @P9_QTLINK: hard-link (9P2000.u)
+ * @P9_QTFILE: normal files
+ *
+ * QID types are a subset of permissions - they are primarily
+ * used to differentiate semantics for a file system entity via
+ * a jump-table.  Their value is also the most signifigant 16 bits
+ * of the permission_t
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+enum p9_qid_t {
 	P9_QTDIR = 0x80,
 	P9_QTAPPEND = 0x40,
 	P9_QTEXCL = 0x20,
@@ -140,6 +254,7 @@ enum {
 	P9_QTFILE = 0x00,
 };
 
+/* 9P Magic Numbers */
 #define P9_NOTAG	(u16)(~0)
 #define P9_NOFID	(u32)(~0)
 #define P9_MAXWELEM	16
@@ -147,19 +262,69 @@ enum {
 /* ample room for Twrite/Rread header */
 #define P9_IOHDRSZ	24
 
+/**
+ * struct p9_str - length prefixed string type
+ * @len: length of the string
+ * @str: the string
+ *
+ * The protocol uses length prefixed strings for all
+ * string data, so we replicate that for our internal
+ * string members.
+ */
+
 struct p9_str {
 	u16 len;
 	char *str;
 };
 
-/* qids are the unique ID for a file (like an inode */
+/**
+ * struct p9_qid - file system entity information
+ * @type: 8-bit type &p9_qid_t
+ * @version: 16-bit monotonically incrementing version number
+ * @path: 64-bit per-server-unique ID for a file system element
+ *
+ * qids are identifiers used by 9P servers to track file system
+ * entities.  The type is used to differentiate semantics for operations
+ * on the entity (ie. read means something different on a directory than
+ * on a file).  The path provides a server unique index for an entity
+ * (roughly analogous to an inode number), while the version is updated
+ * every time a file is modified and can be used to maintain cache
+ * coherency between clients and serves.
+ * Servers will often differentiate purely synthetic entities by setting
+ * their version to 0, signaling that they should never be cached and
+ * should be accessed synchronously.
+ *
+ * See Also://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+
 struct p9_qid {
 	u8 type;
 	u32 version;
 	u64 path;
 };
 
-/* Plan 9 file metadata (stat) structure */
+/**
+ * struct p9_stat - file system metadata information
+ * @size: length prefix for this stat structure instance
+ * @type: the type of the server (equivilent to a major number)
+ * @dev: the sub-type of the server (equivilent to a minor number)
+ * @qid: unique id from the server of type &p9_qid
+ * @mode: Plan 9 format permissions of type &p9_perm_t
+ * @atime: Last access/read time
+ * @mtime: Last modify/write time
+ * @length: file length
+ * @name: last element of path (aka filename) in type &p9_str
+ * @uid: owner name in type &p9_str
+ * @gid: group owner in type &p9_str
+ * @muid: last modifier in type &p9_str
+ * @extension: area used to encode extended UNIX support in type &p9_str
+ * @n_uid: numeric user id of owner (part of 9p2000.u extension)
+ * @n_gid: numeric group id (part of 9p2000.u extension)
+ * @n_muid: numeric user id of laster modifier (part of 9p2000.u extension)
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+
 struct p9_stat {
 	u16 size;
 	u16 type;
@@ -179,10 +344,14 @@ struct p9_stat {
 	u32 n_muid;			/* 9p2000.u extensions */
 };
 
-/* file metadata (stat) structure used to create Twstat message
-   The is similar to p9_stat, but the strings don't point to
-   the same memory block and should be freed separately
-*/
+/*
+ * file metadata (stat) structure used to create Twstat message
+ * The is identical to &p9_stat, but the strings don't point to
+ * the same memory block and should be freed separately
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+
 struct p9_wstat {
 	u16 size;
 	u16 type;
@@ -335,10 +504,20 @@ struct p9_twstat {
 struct p9_rwstat {
 };
 
-/*
-  * fcall is the primary packet structure
-  *
-  */
+/**
+ * struct p9_fcall - primary packet structure
+ * @size: prefixed length of the structure
+ * @id: protocol operating identifier of type &p9_msg_t
+ * @tag: transaction id of the request
+ * @sdata: payload
+ * @params: per-operation parameters
+ *
+ * &p9_fcall represents the structure for all 9P RPC
+ * transactions.  Requests are packaged into fcalls, and reponses
+ * must be extracted from them.
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/fcall
+ */
 
 struct p9_fcall {
 	u32 size;
@@ -416,4 +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 */
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index e52f93d9ac5..c936dd14de4 100644
--- a/