[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;
+}