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