fs/9p/fid.c

   1 /*
   2  * V9FS FID Management
   3  *
   4  *  Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to:
  18  *  Free Software Foundation
  19  *  51 Franklin Street, Fifth Floor
  20  *  Boston, MA  02111-1301  USA
  21  *
  22  */
  23
  24 #include <linux/config.h>
  25 #include <linux/module.h>
  26 #include <linux/errno.h>
  27 #include <linux/fs.h>
  28 #include <linux/idr.h>
  29
  30 #include "debug.h"
  31 #include "v9fs.h"
  32 #include "9p.h"
  33 #include "v9fs_vfs.h"
  34 #include "fid.h"
  35
  36 /**
  37  * v9fs_fid_insert - add a fid to a dentry
  38  * @fid: fid to add
  39  * @dentry: dentry that it is being added to
  40  *
  41  */
  42
  43 int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
  44 {
  45         struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
  46         dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
  47                 dentry->d_iname, dentry);
  48         if (dentry->d_fsdata == NULL) {
  49                 dentry->d_fsdata =
  50                     kmalloc(sizeof(struct list_head), GFP_KERNEL);
  51                 if (dentry->d_fsdata == NULL) {
  52                         dprintk(DEBUG_ERROR, "Out of memory\n");
  53                         return -ENOMEM;
  54                 }
  55                 fid_list = (struct list_head *)dentry->d_fsdata;
  56                 INIT_LIST_HEAD(fid_list);       /* Initialize list head */
  57         }
  58
  59         fid->uid = current->uid;
  60         list_add(&fid->list, fid_list);
  61         return 0;
  62 }
  63
  64 /**
  65  * v9fs_fid_create - allocate a FID structure
  66  * @dentry - dentry to link newly created fid to
  67  *
  68  */
  69
  70 struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
  71 {
  72         struct v9fs_fid *new;
  73
  74         dprintk(DEBUG_9P, "fid create fid %d\n", fid);
  75         new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  76         if (new == NULL) {
  77                 dprintk(DEBUG_ERROR, "Out of Memory\n");
  78                 return ERR_PTR(-ENOMEM);
  79         }
  80
  81         new->fid = fid;
  82         new->v9ses = v9ses;
  83         new->fidopen = 0;
  84         new->fidclunked = 0;
  85         new->iounit = 0;
  86         new->rdir_pos = 0;
  87         new->rdir_fcall = NULL;
  88         INIT_LIST_HEAD(&new->list);
  89
  90         return new;
  91 }
  92
  93 /**
  94  * v9fs_fid_destroy - deallocate a FID structure
  95  * @fid: fid to destroy
  96  *
  97  */
  98
  99 void v9fs_fid_destroy(struct v9fs_fid *fid)
 100 {
 101         list_del(&fid->list);
 102         kfree(fid);
 103 }
 104
 105 /**
 106  * v9fs_fid_lookup - retrieve the right fid from a  particular dentry
 107  * @dentry: dentry to look for fid in
 108  * @type: intent of lookup (operation or traversal)
 109  *
 110  * find a fid in the dentry
 111  *
 112  * TODO: only match fids that have the same uid as current user
 113  *
 114  */
 115
 116 struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
 117 {
 118         struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
 119         struct v9fs_fid *return_fid = NULL;
 120
 121         dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
 122
 123         if (fid_list)
 124                 return_fid = list_entry(fid_list->next, struct v9fs_fid, list);
 125
 126         if (!return_fid) {
 127                 dprintk(DEBUG_ERROR, "Couldn't find a fid in dentry\n");
 128         }
 129
 130         return return_fid;
 131 }