[PATCH] v9fs: VFS superblock operations and glue

This part of the patch contains VFS superblock and mapping code.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 448 insertions, 0 deletions

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
new file mode 100644
index 0000000..14d663e
--- /dev/null
+++ b/fs/9p/v9fs.c
@@ -0,0 +1,448 @@
+/*
+ *  linux/fs/9p/v9fs.c
+ *
+ *  This file contains functions assisting in mapping VFS to 9P2000
+ *
+ *  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 as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  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/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/parser.h>
+#include <linux/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "v9fs_vfs.h"
+#include "transport.h"
+#include "mux.h"
+#include "conv.h"
+
+/* TODO: sysfs or debugfs interface */
+int v9fs_debug_level = 0;	/* feature-rific global debug level  */
+
+/*
+  * Option Parsing (code inspired by NFS code)
+  *
+  */
+
+enum {
+	/* Options that take integer arguments */
+	Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
+	Opt_rfdno, Opt_wfdno,
+	/* String options */
+	Opt_name, Opt_remotename,
+	/* Options that take no arguments */
+	Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
+	/* Error token */
+	Opt_err
+};
+
+static match_table_t tokens = {
+	{Opt_port, "port=%u"},
+	{Opt_msize, "msize=%u"},
+	{Opt_uid, "uid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_afid, "afid=%u"},
+	{Opt_rfdno, "rfdno=%u"},
+	{Opt_wfdno, "wfdno=%u"},
+	{Opt_debug, "debug=%u"},
+	{Opt_name, "name=%s"},
+	{Opt_remotename, "aname=%s"},
+	{Opt_unix, "proto=unix"},
+	{Opt_tcp, "proto=tcp"},
+	{Opt_fd, "proto=fd"},
+	{Opt_tcp, "tcp"},
+	{Opt_unix, "unix"},
+	{Opt_fd, "fd"},
+	{Opt_legacy, "noextend"},
+	{Opt_nodevmap, "nodevmap"},
+	{Opt_err, NULL}
+};
+
+/*
+ *  Parse option string.
+ */
+
+/**
+ * v9fs_parse_options - parse mount options into session structure
+ * @options: options string passed from mount
+ * @v9ses: existing v9fs session information
+ *
+ */
+
+static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	int ret;
+
+	/* setup defaults */
+	v9ses->port = V9FS_PORT;
+	v9ses->maxdata = 9000;
+	v9ses->proto = PROTO_TCP;
+	v9ses->extended = 1;
+	v9ses->afid = ~0;
+	v9ses->debug = 0;
+	v9ses->rfdno = ~0;
+	v9ses->wfdno = ~0;
+
+	if (!options)
+		return;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+		token = match_token(p, tokens, args);
+		if (token < Opt_name) {
+			if ((ret = match_int(&args[0], &option)) < 0) {
+				dprintk(DEBUG_ERROR,
+					"integer field, but no integer?\n");
+				continue;
+			}
+
+		}
+		switch (token) {
+		case Opt_port:
+			v9ses->port = option;
+			break;
+		case Opt_msize:
+			v9ses->maxdata = option;
+			break;
+		case Opt_uid:
+			v9ses->uid = option;
+			break;
+		case Opt_gid:
+			v9ses->gid = option;
+			break;
+		case Opt_afid:
+			v9ses->afid = option;
+			break;
+		case Opt_rfdno:
+			v9ses->rfdno = option;
+			break;
+		case Opt_wfdno:
+			v9ses->wfdno = option;
+			break;
+		case Opt_debug:
+			v9ses->debug = option;
+			break;
+		case Opt_tcp:
+			v9ses->proto = PROTO_TCP;
+			break;
+		case Opt_unix:
+			v9ses->proto = PROTO_UNIX;
+			break;
+		case Opt_fd:
+			v9ses->proto = PROTO_FD;
+			break;
+		case Opt_name:
+			match_strcpy(v9ses->name, &args[0]);
+			break;
+		case Opt_remotename:
+			match_strcpy(v9ses->remotename, &args[0]);
+			break;
+		case Opt_legacy:
+			v9ses->extended = 0;
+			break;
+		case Opt_nodevmap:
+			v9ses->nodev = 1;
+			break;
+		default:
+			continue;
+		}
+	}
+}
+
+/**
+ * v9fs_inode2v9ses - safely extract v9fs session info from super block
+ * @inode: inode to extract information from
+ *
+ * Paranoid function to extract v9ses information from superblock,
+ * if anything is missing it will report an error.
+ *
+ */
+
+struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
+{
+	return (inode->i_sb->s_fs_info);
+}
+
+/**
+ * v9fs_get_idpool - 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 v9fs_get_idpool(struct v9fs_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) {
+		eprintk(KERN_WARNING, "Interrupted while locking\n");
+		return -1;
+	}
+
+	error = idr_get_new(&p->pool, NULL, &i);
+	up(&p->lock);
+
+	if (error == -EAGAIN)
+		goto retry;
+	else if (error)
+		return -1;
+
+	return i;
+}
+
+/**
+ * v9fs_put_idpool - 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 v9fs_put_idpool(int id, struct v9fs_idpool *p)
+{
+	if (down_interruptible(&p->lock) == -EINTR) {
+		eprintk(KERN_WARNING, "Interrupted while locking\n");
+		return;
+	}
+	idr_remove(&p->pool, id);
+	up(&p->lock);
+}
+
+/**
+ * v9fs_session_init - initialize session
+ * @v9ses: session information structure
+ * @dev_name: device being mounted
+ * @data: options
+ *
+ */
+
+int
+v9fs_session_init(struct v9fs_session_info *v9ses,
+		  const char *dev_name, char *data)
+{
+	struct v9fs_fcall *fcall = NULL;
+	struct v9fs_transport *trans_proto;
+	int n = 0;
+	int newfid = -1;
+	int retval = -EINVAL;
+
+	v9ses->name = __getname();
+	if (!v9ses->name)
+		return -ENOMEM;
+
+	v9ses->remotename = __getname();
+	if (!v9ses->remotename) {
+		putname(v9ses->name);
+		return -ENOMEM;
+	}
+
+	strcpy(v9ses->name, V9FS_DEFUSER);
+	strcpy(v9ses->remotename, V9FS_DEFANAME);
+
+	v9fs_parse_options(data, v9ses);
+
+	/* set global debug level */
+	v9fs_debug_level = v9ses->debug;
+
+	/* id pools that are session-dependent: FIDs and TIDs */
+	idr_init(&v9ses->fidpool.pool);
+	init_MUTEX(&v9ses->fidpool.lock);
+	idr_init(&v9ses->tidpool.pool);
+	init_MUTEX(&v9ses->tidpool.lock);
+
+
+	switch (v9ses->proto) {
+	case PROTO_TCP:
+		trans_proto = &v9fs_trans_tcp;
+		break;
+	case PROTO_UNIX:
+		trans_proto = &v9fs_trans_unix;
+		*v9ses->remotename = 0;
+		break;
+	case PROTO_FD:
+		trans_proto = &v9fs_trans_fd;
+		*v9ses->remotename = 0;
+		if((v9ses->wfdno == ~0) || (v9ses->rfdno == ~0)) {
+			printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
+			retval = -ENOPROTOOPT;
+			goto SessCleanUp;
+		}
+		break;
+	default:
+		printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
+		retval = -ENOPROTOOPT;
+		goto SessCleanUp;
+	};
+
+	v9ses->transport = trans_proto;
+
+	if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
+		eprintk(KERN_ERR, "problem initializing transport\n");
+		goto SessCleanUp;
+	}
+
+	v9ses->inprogress = 0;
+	v9ses->shutdown = 0;
+	v9ses->session_hung = 0;
+
+	if ((retval = v9fs_mux_init(v9ses, dev_name)) < 0) {
+		dprintk(DEBUG_ERROR, "problem initializing mux\n");
+		goto SessCleanUp;
+	}
+
+	if (v9ses->afid == ~0) {
+		if (v9ses->extended)
+			retval =
+			    v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
+					   &fcall);
+		else
+			retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
+						&fcall);
+
+		if (retval < 0) {
+			dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
+			goto FreeFcall;
+		}
+
+		/* Really should check for 9P1 and report error */
+		if (!strcmp(fcall->params.rversion.version, "9P2000.u")) {
+			dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
+			v9ses->extended = 1;
+		} else {
+			dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
+			v9ses->extended = 0;
+		}
+
+		n = fcall->params.rversion.msize;
+		kfree(fcall);
+
+		if (n < v9ses->maxdata)
+			v9ses->maxdata = n;
+	}
+
+	newfid = v9fs_get_idpool(&v9ses->fidpool);
+	if (newfid < 0) {
+		eprintk(KERN_WARNING, "couldn't allocate FID\n");
+		retval = -ENOMEM;
+		goto SessCleanUp;
+	}
+	/* it is a little bit ugly, but we have to prevent newfid */
+	/* being the same as afid, so if it is, get a new fid     */
+	if (v9ses->afid != ~0 && newfid == v9ses->afid) {
+		newfid = v9fs_get_idpool(&v9ses->fidpool);
+		if (newfid < 0) {
+			eprintk(KERN_WARNING, "couldn't allocate FID\n");
+			retval = -ENOMEM;
+			goto SessCleanUp;
+		}
+	}
+
+	if ((retval =
+	     v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
+			   v9ses->afid, NULL))
+	    < 0) {
+		dprintk(DEBUG_ERROR, "cannot attach\n");
+		goto SessCleanUp;
+	}
+
+	if (v9ses->afid != ~0) {
+		if (v9fs_t_clunk(v9ses, v9ses->afid, NULL))
+			dprintk(DEBUG_ERROR, "clunk failed\n");
+	}
+
+	return newfid;
+
+      FreeFcall:
+	kfree(fcall);
+
+      SessCleanUp:
+	v9fs_session_close(v9ses);
+	return retval;
+}
+
+/**
+ * v9fs_session_close - shutdown a session
+ * @v9ses: session information structure
+ *
+ */
+
+void v9fs_session_close(struct v9fs_session_info *v9ses)
+{
+	if (v9ses->recvproc) {
+		send_sig(SIGKILL, v9ses->recvproc, 1);
+		wait_for_completion(&v9ses->proccmpl);
+	}
+
+	if (v9ses->transport)
+		v9ses->transport->close(v9ses->transport);
+
+	putname(v9ses->name);
+	putname(v9ses->remotename);
+}
+
+extern int v9fs_error_init(void);
+
+/**
+ * v9fs_init - Initialize module
+ *
+ */
+
+static int __init init_v9fs(void)
+{
+	v9fs_error_init();
+
+	printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
+
+	return register_filesystem(&v9fs_fs_type);
+}
+
+/**
+ * v9fs_init - shutdown module
+ *
+ */
+
+static void __exit exit_v9fs(void)
+{
+	unregister_filesystem(&v9fs_fs_type);
+}
+
+module_init(init_v9fs)
+module_exit(exit_v9fs)
+
+MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
+MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
+MODULE_LICENSE("GPL");