blob: eda449778fa55d5e96e7342acdc6920f73d4c3f3 [file] [log] [blame]
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -07001/*
2 * V9FS FID Management
3 *
4 * Copyright (C) 2005 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"
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070034#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
43static 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 fid->pid = current->pid;
61 list_add(&fid->list, fid_list);
62 return 0;
63}
64
65/**
66 * v9fs_fid_create - allocate a FID structure
67 * @dentry - dentry to link newly created fid to
68 *
69 */
70
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -070071struct v9fs_fid *v9fs_fid_create(struct dentry *dentry,
72 struct v9fs_session_info *v9ses, int fid, int create)
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070073{
74 struct v9fs_fid *new;
75
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -070076 dprintk(DEBUG_9P, "fid create dentry %p, fid %d, create %d\n",
77 dentry, fid, create);
78
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070079 new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
80 if (new == NULL) {
81 dprintk(DEBUG_ERROR, "Out of Memory\n");
82 return ERR_PTR(-ENOMEM);
83 }
84
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -070085 new->fid = fid;
86 new->v9ses = v9ses;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070087 new->fidopen = 0;
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -070088 new->fidcreate = create;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070089 new->fidclunked = 0;
90 new->iounit = 0;
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -070091 new->rdir_pos = 0;
92 new->rdir_fcall = NULL;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070093
94 if (v9fs_fid_insert(new, dentry) == 0)
95 return new;
96 else {
97 dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
98 kfree(new);
99 return NULL;
100 }
101}
102
103/**
104 * v9fs_fid_destroy - deallocate a FID structure
105 * @fid: fid to destroy
106 *
107 */
108
109void v9fs_fid_destroy(struct v9fs_fid *fid)
110{
111 list_del(&fid->list);
112 kfree(fid);
113}
114
115/**
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700116 * v9fs_fid_walk_up - walks from the process current directory
117 * up to the specified dentry.
118 */
119static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
120{
121 int fidnum, cfidnum, err;
122 struct v9fs_fid *cfid;
123 struct dentry *cde;
124 struct v9fs_session_info *v9ses;
125
126 v9ses = v9fs_inode2v9ses(current->fs->pwd->d_inode);
127 cfid = v9fs_fid_lookup(current->fs->pwd);
128 if (cfid == NULL) {
129 dprintk(DEBUG_ERROR, "process cwd doesn't have a fid\n");
130 return ERR_PTR(-ENOENT);
131 }
132
133 cfidnum = cfid->fid;
134 cde = current->fs->pwd;
135 /* TODO: take advantage of multiwalk */
136
137 fidnum = v9fs_get_idpool(&v9ses->fidpool);
138 if (fidnum < 0) {
139 dprintk(DEBUG_ERROR, "could not get a new fid num\n");
140 err = -ENOENT;
141 goto clunk_fid;
142 }
143
144 while (cde != dentry) {
145 if (cde == cde->d_parent) {
146 dprintk(DEBUG_ERROR, "can't find dentry\n");
147 err = -ENOENT;
148 goto clunk_fid;
149 }
150
151 err = v9fs_t_walk(v9ses, cfidnum, fidnum, "..", NULL);
152 if (err < 0) {
153 dprintk(DEBUG_ERROR, "problem walking to parent\n");
154 goto clunk_fid;
155 }
156
157 cfidnum = fidnum;
158 cde = cde->d_parent;
159 }
160
161 return v9fs_fid_create(dentry, v9ses, fidnum, 0);
162
163clunk_fid:
Latchesar Ionkov3cf64292006-01-08 01:04:58 -0800164 v9fs_t_clunk(v9ses, fidnum);
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700165 return ERR_PTR(err);
166}
167
168/**
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700169 * v9fs_fid_lookup - retrieve the right fid from a particular dentry
170 * @dentry: dentry to look for fid in
171 * @type: intent of lookup (operation or traversal)
172 *
173 * search list of fids associated with a dentry for a fid with a matching
174 * thread id or uid. If that fails, look up the dentry's parents to see if you
175 * can find a matching fid.
176 *
177 */
178
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700179struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700180{
181 struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
182 struct v9fs_fid *current_fid = NULL;
183 struct v9fs_fid *temp = NULL;
184 struct v9fs_fid *return_fid = NULL;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700185
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700186 dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700187
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700188 if (fid_list) {
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700189 list_for_each_entry_safe(current_fid, temp, fid_list, list) {
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700190 if (!current_fid->fidcreate) {
191 return_fid = current_fid;
192 break;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700193 }
194 }
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700195
196 if (!return_fid)
197 return_fid = current_fid;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700198 }
199
200 /* we are at the root but didn't match */
201 if ((!return_fid) && (dentry->d_parent == dentry)) {
202 /* TODO: clone attach with new uid */
203 return_fid = current_fid;
204 }
205
206 if (!return_fid) {
207 struct dentry *par = current->fs->pwd->d_parent;
208 int count = 1;
209 while (par != NULL) {
210 if (par == dentry)
211 break;
212 count++;
213 if (par == par->d_parent) {
214 dprintk(DEBUG_ERROR,
215 "got to root without finding dentry\n");
216 break;
217 }
218 par = par->d_parent;
219 }
220
221/* XXX - there may be some duplication we can get rid of */
222 if (par == dentry) {
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700223 return_fid = v9fs_fid_walk_up(dentry);
224 if (IS_ERR(return_fid))
225 return_fid = NULL;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700226 }
227 }
228
229 return return_fid;
230}
Latchesar Ionkov0b8dd172005-09-27 21:45:24 -0700231
232struct v9fs_fid *v9fs_fid_get_created(struct dentry *dentry)
233{
234 struct list_head *fid_list;
235 struct v9fs_fid *fid, *ftmp, *ret;
236
237 dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
238 fid_list = (struct list_head *)dentry->d_fsdata;
239 ret = NULL;
240 if (fid_list) {
241 list_for_each_entry_safe(fid, ftmp, fid_list, list) {
242 if (fid->fidcreate && fid->pid == current->pid) {
243 list_del(&fid->list);
244 ret = fid;
245 break;
246 }
247 }
248 }
249
250 dprintk(DEBUG_9P, "return %p\n", ret);
251 return ret;
252}