1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/*
* V9FS FID Management
*
* Copyright (C) 2005 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include "debug.h"
#include "v9fs.h"
#include "9p.h"
#include "v9fs_vfs.h"
#include "fid.h"
/**
* v9fs_fid_insert - add a fid to a dentry
* @fid: fid to add
* @dentry: dentry that it is being added to
*
*/
int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
dentry->d_iname, dentry);
if (dentry->d_fsdata == NULL) {
dentry->d_fsdata =
kmalloc(sizeof(struct list_head), GFP_KERNEL);
if (dentry->d_fsdata == NULL) {
dprintk(DEBUG_ERROR, "Out of memory\n");
return -ENOMEM;
}
fid_list = (struct list_head *)dentry->d_fsdata;
INIT_LIST_HEAD(fid_list); /* Initialize list head */
}
fid->uid = current->uid;
fid->pid = current->pid;
list_add(&fid->list, fid_list);
return 0;
}
/**
* v9fs_fid_create - allocate a FID structure
* @dentry - dentry to link newly created fid to
*
*/
struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
{
struct v9fs_fid *new;
dprintk(DEBUG_9P, "fid create fid %d\n", fid);
new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
if (new == NULL) {
dprintk(DEBUG_ERROR, "Out of Memory\n");
return ERR_PTR(-ENOMEM);
}
new->fid = fid;
new->v9ses = v9ses;
new->fidopen = 0;
new->fidclunked = 0;
new->iounit = 0;
new->rdir_pos = 0;
new->rdir_fcall = NULL;
INIT_LIST_HEAD(&new->list);
return new;
}
/**
* v9fs_fid_destroy - deallocate a FID structure
* @fid: fid to destroy
*
*/
void v9fs_fid_destroy(struct v9fs_fid *fid)
{
list_del(&fid->list);
kfree(fid);
}
/**
* v9fs_fid_walk_up - walks from the process current directory
* up to the specified dentry.
*/
static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
{
int fidnum, cfidnum, err;
struct v9fs_fid *cfid, *fid;
struct dentry *cde;
struct v9fs_session_info *v9ses;
v9ses = v9fs_inode2v9ses(current->fs->pwd->d_inode);
cfid = v9fs_fid_lookup(current->fs->pwd);
if (cfid == NULL) {
dprintk(DEBUG_ERROR, "process cwd doesn't have a fid\n");
return ERR_PTR(-ENOENT);
}
cfidnum = cfid->fid;
cde = current->fs->pwd;
/* TODO: take advantage of multiwalk */
fidnum = v9fs_get_idpool(&v9ses->fidpool);
if (fidnum < 0) {
dprintk(DEBUG_ERROR, "could not get a new fid num\n");
err = -ENOENT;
goto clunk_fid;
}
while (cde != dentry) {
if (cde == cde->d_parent) {
dprintk(DEBUG_ERROR, "can't find dentry\n");
err = -ENOENT;
goto clunk_fid;
}
err = v9fs_t_walk(v9ses, cfidnum, fidnum, "..", NULL);
if (err < 0) {
dprintk(DEBUG_ERROR, "problem walking to parent\n");
goto clunk_fid;
}
cfidnum = fidnum;
cde = cde->d_parent;
}
fid = v9fs_fid_create(v9ses, fidnum);
if (fid) {
err = v9fs_fid_insert(fid, dentry);
if (err < 0) {
kfree(fid);
goto clunk_fid;
}
}
return fid;
clunk_fid:
v9fs_t_clunk(v9ses, fidnum);
return ERR_PTR(err);
}
/**
* v9fs_fid_lookup - retrieve the right fid from a particular dentry
* @dentry: dentry to look for fid in
* @type: intent of lookup (operation or traversal)
*
* search list of fids associated with a dentry for a fid with a matching
* thread id or uid. If that fails, look up the dentry's parents to see if you
* can find a matching fid.
*
*/
struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
struct v9fs_fid *return_fid = NULL;
dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
if (fid_list)
return_fid = list_entry(fid_list->next, struct v9fs_fid, list);
if (!return_fid) {
struct dentry *par = current->fs->pwd->d_parent;
int count = 1;
while (par != NULL) {
if (par == dentry)
break;
count++;
if (par == par->d_parent) {
dprintk(DEBUG_ERROR,
"got to root without finding dentry\n");
break;
}
par = par->d_parent;
}
/* XXX - there may be some duplication we can get rid of */
if (par == dentry) {
return_fid = v9fs_fid_walk_up(dentry);
if (IS_ERR(return_fid))
return_fid = NULL;
}
}
return return_fid;
}
|
