fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / fs / 9p / fid.c

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index c4d13bf..a9b6301 100644 (file)
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -4,9 +4,8 @@
  *  Copyright (C) 2005, 2006 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.
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -21,11 +20,12 @@
  *
  */
 
-#include <linux/config.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
+#include <linux/sched.h>
 #include <linux/idr.h>
+#include <asm/semaphore.h>
 
 #include "debug.h"
 #include "v9fs.h"
@@ -85,6 +85,7 @@ struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
        new->iounit = 0;
        new->rdir_pos = 0;
        new->rdir_fcall = NULL;
+       init_MUTEX(&new->lock);
        INIT_LIST_HEAD(&new->list);
 
        return new;
@@ -103,11 +104,11 @@ void v9fs_fid_destroy(struct v9fs_fid *fid)
 }
 
 /**
- * v9fs_fid_lookup - retrieve the right fid from a  particular dentry
+ * v9fs_fid_lookup - return a locked fid from a dentry
  * @dentry: dentry to look for fid in
- * @type: intent of lookup (operation or traversal)
  *
- * find a fid in the dentry
+ * find a fid in the dentry, obtain its semaphore and return a reference to it.
+ * code calling lookup is responsible for releasing lock
  *
  * TODO: only match fids that have the same uid as current user
  *
@@ -125,7 +126,68 @@ struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
 
        if (!return_fid) {
                dprintk(DEBUG_ERROR, "Couldn't find a fid in dentry\n");
+               return_fid = ERR_PTR(-EBADF);
        }
 
+       if(down_interruptible(&return_fid->lock))
+               return ERR_PTR(-EINTR);
+
        return return_fid;
 }
+
+/**
+ * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and release it
+ * @dentry: dentry to look for fid in
+ *
+ * find a fid in the dentry and then clone to a new private fid
+ *
+ * TODO: only match fids that have the same uid as current user
+ *
+ */
+
+struct v9fs_fid *v9fs_fid_clone(struct dentry *dentry)
+{
+       struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
+       struct v9fs_fid *base_fid, *new_fid = ERR_PTR(-EBADF);
+       struct v9fs_fcall *fcall = NULL;
+       int fid, err;
+
+       base_fid = v9fs_fid_lookup(dentry);
+
+       if(IS_ERR(base_fid))
+               return base_fid;
+
+       if(base_fid) {  /* clone fid */
+               fid = v9fs_get_idpool(&v9ses->fidpool);
+               if (fid < 0) {
+                       eprintk(KERN_WARNING, "newfid fails!\n");
+                       new_fid = ERR_PTR(-ENOSPC);
+                       goto Release_Fid;
+               }
+
+               err = v9fs_t_walk(v9ses, base_fid->fid, fid, NULL, &fcall);
+               if (err < 0) {
+                       dprintk(DEBUG_ERROR, "clone walk didn't work\n");
+                       v9fs_put_idpool(fid, &v9ses->fidpool);
+                       new_fid = ERR_PTR(err);
+                       goto Free_Fcall;
+               }
+               new_fid = v9fs_fid_create(v9ses, fid);
+               if (new_fid == NULL) {
+                       dprintk(DEBUG_ERROR, "out of memory\n");
+                       new_fid = ERR_PTR(-ENOMEM);
+               }
+Free_Fcall:
+               kfree(fcall);
+       }
+
+Release_Fid:
+       up(&base_fid->lock);
+       return new_fid;
+}
+
+void v9fs_fid_clunk(struct v9fs_session_info *v9ses, struct v9fs_fid *fid)
+{
+       v9fs_t_clunk(v9ses, fid->fid);
+       v9fs_fid_destroy(fid);
+}