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Eric Van Hensbergen3ed84912005-09-09 13:04:24 -07001/*
2 * V9FS FID Management
3 *
Latchesar Ionkovba176742007-10-17 14:31:07 -05004 * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
Eric Van Hensbergen46f6dac2006-03-02 02:54:33 -08005 * Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -07006 *
7 * This program is free software; you can redistribute it and/or modify
Eric Van Hensbergen42e8c502006-03-25 03:07:28 -08008 * it under the terms of the GNU General Public License version 2
9 * as published by the Free Software Foundation.
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070010 *
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
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070024#include <linux/module.h>
25#include <linux/errno.h>
26#include <linux/fs.h>
Al Viro914e2632006-10-18 13:55:46 -040027#include <linux/sched.h>
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070028#include <linux/idr.h>
Eric Van Hensbergenda977b22007-01-26 00:57:06 -080029#include <asm/semaphore.h>
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050030#include <net/9p/9p.h>
31#include <net/9p/client.h>
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070032
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070033#include "v9fs.h"
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070034#include "v9fs_vfs.h"
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070035#include "fid.h"
36
37/**
Latchesar Ionkovba176742007-10-17 14:31:07 -050038 * v9fs_fid_add - add a fid to a dentry
39 * @dentry: dentry that the fid is being added to
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070040 * @fid: fid to add
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070041 *
42 */
43
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050044int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070045{
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050046 struct v9fs_dentry *dent;
47
48 P9_DPRINTK(P9_DEBUG_VFS, "fid %d dentry %s\n",
49 fid->fid, dentry->d_iname);
50
51 dent = dentry->d_fsdata;
52 if (!dent) {
53 dent = kmalloc(sizeof(struct v9fs_dentry), GFP_KERNEL);
54 if (!dent)
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070055 return -ENOMEM;
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050056
57 spin_lock_init(&dent->lock);
58 INIT_LIST_HEAD(&dent->fidlist);
59 dentry->d_fsdata = dent;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070060 }
61
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050062 spin_lock(&dent->lock);
63 list_add(&fid->dlist, &dent->fidlist);
64 spin_unlock(&dent->lock);
65
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -070066 return 0;
67}
68
69/**
Latchesar Ionkovba176742007-10-17 14:31:07 -050070 * v9fs_fid_find - retrieve a fid that belongs to the specified uid
71 * @dentry: dentry to look for fid in
72 * @uid: return fid that belongs to the specified user
73 * @any: if non-zero, return any fid associated with the dentry
74 *
75 */
76
77static struct p9_fid *v9fs_fid_find(struct dentry *dentry, u32 uid, int any)
78{
79 struct v9fs_dentry *dent;
80 struct p9_fid *fid, *ret;
81
82 P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n",
83 dentry->d_iname, dentry, uid, any);
84 dent = (struct v9fs_dentry *) dentry->d_fsdata;
85 ret = NULL;
86 if (dent) {
87 spin_lock(&dent->lock);
88 list_for_each_entry(fid, &dent->fidlist, dlist) {
89 if (any || fid->uid == uid) {
90 ret = fid;
91 break;
92 }
93 }
94 spin_unlock(&dent->lock);
95 }
96
97 return ret;
98}
99
100/**
101 * v9fs_fid_lookup - lookup for a fid, try to walk if not found
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700102 * @dentry: dentry to look for fid in
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700103 *
Latchesar Ionkovba176742007-10-17 14:31:07 -0500104 * Look for a fid in the specified dentry for the current user.
105 * If no fid is found, try to create one walking from a fid from the parent
106 * dentry (if it has one), or the root dentry. If the user haven't accessed
107 * the fs yet, attach now and walk from the root.
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700108 */
109
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -0500110struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700111{
Latchesar Ionkovba176742007-10-17 14:31:07 -0500112 int i, n, l, clone, any, access;
113 u32 uid;
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -0500114 struct p9_fid *fid;
Latchesar Ionkovba176742007-10-17 14:31:07 -0500115 struct dentry *d, *ds;
116 struct v9fs_session_info *v9ses;
117 char **wnames, *uname;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700118
Latchesar Ionkovba176742007-10-17 14:31:07 -0500119 v9ses = v9fs_inode2v9ses(dentry->d_inode);
120 access = v9ses->flags & V9FS_ACCESS_MASK;
121 switch (access) {
122 case V9FS_ACCESS_SINGLE:
123 case V9FS_ACCESS_USER:
124 uid = current->fsuid;
125 any = 0;
126 break;
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700127
Latchesar Ionkovba176742007-10-17 14:31:07 -0500128 case V9FS_ACCESS_ANY:
129 uid = v9ses->uid;
130 any = 1;
131 break;
132
133 default:
134 uid = ~0;
135 any = 0;
136 break;
137 }
138
139 fid = v9fs_fid_find(dentry, uid, any);
140 if (fid)
141 return fid;
142
143 ds = dentry->d_parent;
144 fid = v9fs_fid_find(ds, uid, any);
145 if (!fid) { /* walk from the root */
146 n = 0;
147 for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
148 n++;
149
150 fid = v9fs_fid_find(ds, uid, any);
151 if (!fid) { /* the user is not attached to the fs yet */
152 if (access == V9FS_ACCESS_SINGLE)
153 return ERR_PTR(-EPERM);
154
155 if (v9fs_extended(v9ses))
156 uname = NULL;
157 else
158 uname = v9ses->uname;
159
160 fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
161 v9ses->aname);
162
163 if (IS_ERR(fid))
164 return fid;
165
166 v9fs_fid_add(ds, fid);
167 }
168 } else /* walk from the parent */
169 n = 1;
170
171 if (ds == dentry)
172 return fid;
173
174 wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL);
175 if (!wnames)
176 return ERR_PTR(-ENOMEM);
177
178 for (d = dentry, i = n; i >= 0; i--, d = d->d_parent)
179 wnames[i] = (char *) d->d_name.name;
180
181 clone = 1;
182 i = 0;
183 while (i < n) {
184 l = min(n - i, P9_MAXWELEM);
185 fid = p9_client_walk(fid, l, &wnames[i], clone);
186 if (!fid) {
187 kfree(wnames);
188 return fid;
189 }
190
191 i += l;
192 clone = 0;
193 }
194
195 kfree(wnames);
196 v9fs_fid_add(dentry, fid);
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -0500197 return fid;
198}
Eric Van Hensbergen3ed84912005-09-09 13:04:24 -0700199
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -0500200struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
Eric Van Hensbergenda977b22007-01-26 00:57:06 -0800201{
Latchesar Ionkovba176742007-10-17 14:31:07 -0500202 struct p9_fid *fid, *ret;
Eric Van Hensbergenda977b22007-01-26 00:57:06 -0800203
Latchesar Ionkovba176742007-10-17 14:31:07 -0500204 fid = v9fs_fid_lookup(dentry);
205 if (IS_ERR(fid))
206 return fid;
Eric Van Hensbergenda977b22007-01-26 00:57:06 -0800207
Latchesar Ionkovba176742007-10-17 14:31:07 -0500208 ret = p9_client_walk(fid, 0, NULL, 1);
209 return ret;
Eric Van Hensbergenda977b22007-01-26 00:57:06 -0800210}