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/sched.h>
  27 #include <linux/idr.h>
  28
  29 #include "debug.h"
  30 #include "v9fs.h"
  31 #include "9p.h"
  32 #include "v9fs_vfs.h"
  33 #include "fid.h"
  34
  35 /**
  36  * v9fs_fid_insert - add a fid to a dentry
  37  * @fid: fid to add
  38  * @dentry: dentry that it is being added to
  39  *
  40  */
  41
  42 int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
  43 {
  44         struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
  45         dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
  46                 dentry->d_iname, dentry);
  47         if (dentry->d_fsdata == NULL) {
  48                 dentry->d_fsdata =
  49                     kmalloc(sizeof(struct list_head), GFP_KERNEL);
  50                 if (dentry->d_fsdata == NULL) {
  51                         dprintk(DEBUG_ERROR, "Out of memory\n");
  52                         return -ENOMEM;
  53                 }
  54                 fid_list = (struct list_head *)dentry->d_fsdata;
  55                 INIT_LIST_HEAD(fid_list);       /* Initialize list head */
  56         }
  57
  58         fid->uid = current->uid;
  59         list_add(&fid->list, fid_list);
  60         return 0;
  61 }
  62
  63 /**
  64  * v9fs_fid_create - allocate a FID structure
  65  * @dentry - dentry to link newly created fid to
  66  *
  67  */
  68
  69 struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
  70 {
  71         struct v9fs_fid *new;
  72
  73         dprintk(DEBUG_9P, "fid create fid %d\n", fid);
  74         new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  75         if (new == NULL) {
  76                 dprintk(DEBUG_ERROR, "Out of Memory\n");
  77                 return ERR_PTR(-ENOMEM);
  78         }
  79
  80         new->fid = fid;
  81         new->v9ses = v9ses;
  82         new->fidopen = 0;
  83         new->fidclunked = 0;
  84         new->iounit = 0;
  85         new->rdir_pos = 0;
  86         new->rdir_fcall = NULL;
  87         INIT_LIST_HEAD(&new->list);
  88
  89         return new;
  90 }
  91
  92 /**
  93  * v9fs_fid_destroy - deallocate a FID structure
  94  * @fid: fid to destroy
  95  *
  96  */
  97
  98 void v9fs_fid_destroy(struct v9fs_fid *fid)
  99 {
 100         list_del(&fid->list);
 101         kfree(fid);
 102 }
 103
 104 /**
 105  * v9fs_fid_lookup - retrieve the right fid from a  particular dentry
 106  * @dentry: dentry to look for fid in
 107  * @type: intent of lookup (operation or traversal)
 108  *
 109  * find a fid in the dentry
 110  *
 111  * TODO: only match fids that have the same uid as current user
 112  *
 113  */
 114
 115 struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
 116 {
 117         struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
 118         struct v9fs_fid *return_fid = NULL;
 119
 120         dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
 121
 122         if (fid_list)
 123                 return_fid = list_entry(fid_list->next, struct v9fs_fid, list);
 124
 125         if (!return_fid) {
 126                 dprintk(DEBUG_ERROR, "Couldn't find a fid in dentry\n");
 127         }
 128
 129         return return_fid;
 130 }