[PATCH] v9fs: debug and support routines

This part of the patch contains debug and other misc routines.

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, 241 insertions, 0 deletions

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
new file mode 100644
index 000000000000..821c9c4d76aa
--- /dev/null
+++ b/fs/9p/fid.c
@@ -0,0 +1,241 @@
+/*
+ * V9FS FID Management
+ *
+ *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
+ *
+ *  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/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "v9fs_vfs.h"
+#include "transport.h"
+#include "mux.h"
+#include "conv.h"
+#include "fid.h"
+
+/**
+ * v9fs_fid_insert - add a fid to a dentry
+ * @fid: fid to add
+ * @dentry: dentry that it is being added to
+ *
+ */
+
+static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
+{
+	struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
+	dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
+		dentry->d_iname, dentry);
+	if (dentry->d_fsdata == NULL) {
+		dentry->d_fsdata =
+		    kmalloc(sizeof(struct list_head), GFP_KERNEL);
+		if (dentry->d_fsdata == NULL) {
+			dprintk(DEBUG_ERROR, "Out of memory\n");
+			return -ENOMEM;
+		}
+		fid_list = (struct list_head *)dentry->d_fsdata;
+		INIT_LIST_HEAD(fid_list);	/* Initialize list head */
+	}
+
+	fid->uid = current->uid;
+	fid->pid = current->pid;
+	list_add(&fid->list, fid_list);
+	return 0;
+}
+
+/**
+ * v9fs_fid_create - allocate a FID structure
+ * @dentry - dentry to link newly created fid to
+ *
+ */
+
+struct v9fs_fid *v9fs_fid_create(struct dentry *dentry)
+{
+	struct v9fs_fid *new;
+
+	new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
+	if (new == NULL) {
+		dprintk(DEBUG_ERROR, "Out of Memory\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	new->fid = -1;
+	new->fidopen = 0;
+	new->fidcreate = 0;
+	new->fidclunked = 0;
+	new->iounit = 0;
+
+	if (v9fs_fid_insert(new, dentry) == 0)
+		return new;
+	else {
+		dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
+		kfree(new);
+		return NULL;
+	}
+}
+
+/**
+ * v9fs_fid_destroy - deallocate a FID structure
+ * @fid: fid to destroy
+ *
+ */
+
+void v9fs_fid_destroy(struct v9fs_fid *fid)
+{
+	list_del(&fid->list);
+	kfree(fid);
+}
+
+/**
+ * v9fs_fid_lookup - retrieve the right fid from a  particular dentry
+ * @dentry: dentry to look for fid in
+ * @type: intent of lookup (operation or traversal)
+ *
+ * search list of fids associated with a dentry for a fid with a matching
+ * thread id or uid.  If that fails, look up the dentry's parents to see if you
+ * can find a matching fid.
+ *
+ */
+
+struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry, int type)
+{
+	struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
+	struct v9fs_fid *current_fid = NULL;
+	struct v9fs_fid *temp = NULL;
+	struct v9fs_fid *return_fid = NULL;
+	int found_parent = 0;
+	int found_user = 0;
+
+	dprintk(DEBUG_9P, " dentry: %s (%p) type %d\n", dentry->d_iname, dentry,
+		type);
+
+	if (fid_list && !list_empty(fid_list)) {
+		list_for_each_entry_safe(current_fid, temp, fid_list, list) {
+			if (current_fid->uid == current->uid) {
+				if (return_fid == NULL) {
+					if ((type == FID_OP)
+					    || (!current_fid->fidopen)) {
+						return_fid = current_fid;
+						found_user = 1;
+					}
+				}
+			}
+			if (current_fid->pid == current->real_parent->pid) {
+				if ((return_fid == NULL) || (found_parent)
+				    || (found_user)) {
+					if ((type == FID_OP)
+					    || (!current_fid->fidopen)) {
+						return_fid = current_fid;
+						found_parent = 1;
+						found_user = 0;
+					}
+				}
+			}
+			if (current_fid->pid == current->pid) {
+				if ((type == FID_OP) ||
+				    (!current_fid->fidopen)) {
+					return_fid = current_fid;
+					found_parent = 0;
+					found_user = 0;
+				}
+			}
+		}
+	}
+
+	/* we are at the root but didn't match */
+	if ((!return_fid) && (dentry->d_parent == dentry)) {
+		/* TODO: clone attach with new uid */
+		return_fid = current_fid;
+	}
+
+	if (!return_fid) {
+		struct dentry *par = current->fs->pwd->d_parent;
+		int count = 1;
+		while (par != NULL) {
+			if (par == dentry)
+				break;
+			count++;
+			if (par == par->d_parent) {
+				dprintk(DEBUG_ERROR,
+					"got to root without finding dentry\n");
+				break;
+			}
+			par = par->d_parent;
+		}
+
+/* XXX - there may be some duplication we can get rid of */
+		if (par == dentry) {
+			/* we need to fid_lookup the starting point */
+			int fidnum = -1;
+			int oldfid = -1;
+			int result = -1;
+			struct v9fs_session_info *v9ses =
+			    v9fs_inode2v9ses(current->fs->pwd->d_inode);
+
+			current_fid =
+			    v9fs_fid_lookup(current->fs->pwd, FID_WALK);
+			if (current_fid == NULL) {
+				dprintk(DEBUG_ERROR,
+					"process cwd doesn't have a fid\n");
+				return return_fid;
+			}
+			oldfid = current_fid->fid;
+			par = current->fs->pwd;
+			/* TODO: take advantage of multiwalk */
+
+			fidnum = v9fs_get_idpool(&v9ses->fidpool);
+			if (fidnum < 0) {
+				dprintk(DEBUG_ERROR,
+					"could not get a new fid num\n");
+				return return_fid;
+			}
+
+			while (par != dentry) {
+				result =
+				    v9fs_t_walk(v9ses, oldfid, fidnum, "..",
+						NULL);
+				if (result < 0) {
+					dprintk(DEBUG_ERROR,
+						"problem walking to parent\n");
+
+					break;
+				}
+				oldfid = fidnum;
+				if (par == par->d_parent) {
+					dprintk(DEBUG_ERROR,
+						"can't find dentry\n");
+					break;
+				}
+				par = par->d_parent;
+			}
+			if (par == dentry) {
+				return_fid = v9fs_fid_create(dentry);
+				return_fid->fid = fidnum;
+			}
+		}
+	}
+
+	return return_fid;
+}