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9#include <linux/module.h>
10#include <linux/errno.h>
11#include <linux/fs.h>
12#include <linux/slab.h>
13#include <linux/sched.h>
14#include <linux/idr.h>
15#include <net/9p/9p.h>
16#include <net/9p/client.h>
17
18#include "v9fs.h"
19#include "v9fs_vfs.h"
20#include "fid.h"
21
22static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
23{
24 hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
25}
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30
31
32
33
34void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
35{
36 spin_lock(&dentry->d_lock);
37 __add_fid(dentry, fid);
38 spin_unlock(&dentry->d_lock);
39}
40
41
42
43
44
45
46
47
48static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
49{
50 struct hlist_head *h;
51 struct p9_fid *fid, *ret = NULL;
52
53 p9_debug(P9_DEBUG_VFS, " inode: %p\n", inode);
54
55 spin_lock(&inode->i_lock);
56 h = (struct hlist_head *)&inode->i_private;
57 hlist_for_each_entry(fid, h, ilist) {
58 if (uid_eq(fid->uid, uid)) {
59 refcount_inc(&fid->count);
60 ret = fid;
61 break;
62 }
63 }
64 spin_unlock(&inode->i_lock);
65 return ret;
66}
67
68
69
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72
73
74
75void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid)
76{
77 spin_lock(&inode->i_lock);
78 hlist_add_head(&fid->ilist, (struct hlist_head *)&inode->i_private);
79 spin_unlock(&inode->i_lock);
80}
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89
90
91static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
92{
93 struct p9_fid *fid, *ret;
94
95 p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n",
96 dentry, dentry, from_kuid(&init_user_ns, uid),
97 any);
98 ret = NULL;
99
100 if (d_inode(dentry))
101 ret = v9fs_fid_find_inode(d_inode(dentry), uid);
102
103
104 if (!ret && dentry->d_fsdata) {
105 struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
106 spin_lock(&dentry->d_lock);
107 hlist_for_each_entry(fid, h, dlist) {
108 if (any || uid_eq(fid->uid, uid)) {
109 ret = fid;
110 refcount_inc(&ret->count);
111 break;
112 }
113 }
114 spin_unlock(&dentry->d_lock);
115 }
116
117 return ret;
118}
119
120
121
122
123
124
125static int build_path_from_dentry(struct v9fs_session_info *v9ses,
126 struct dentry *dentry, const unsigned char ***names)
127{
128 int n = 0, i;
129 const unsigned char **wnames;
130 struct dentry *ds;
131
132 for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
133 n++;
134
135 wnames = kmalloc_array(n, sizeof(char *), GFP_KERNEL);
136 if (!wnames)
137 goto err_out;
138
139 for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent)
140 wnames[i] = ds->d_name.name;
141
142 *names = wnames;
143 return n;
144err_out:
145 return -ENOMEM;
146}
147
148static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
149 kuid_t uid, int any)
150{
151 struct dentry *ds;
152 const unsigned char **wnames, *uname;
153 int i, n, l, clone, access;
154 struct v9fs_session_info *v9ses;
155 struct p9_fid *fid, *old_fid = NULL;
156
157 v9ses = v9fs_dentry2v9ses(dentry);
158 access = v9ses->flags & V9FS_ACCESS_MASK;
159 fid = v9fs_fid_find(dentry, uid, any);
160 if (fid)
161 return fid;
162
163
164
165
166
167 down_read(&v9ses->rename_sem);
168 ds = dentry->d_parent;
169 fid = v9fs_fid_find(ds, uid, any);
170 if (fid) {
171
172 struct p9_fid *ofid = fid;
173
174 fid = p9_client_walk(ofid, 1, &dentry->d_name.name, 1);
175 p9_client_clunk(ofid);
176 goto fid_out;
177 }
178 up_read(&v9ses->rename_sem);
179
180
181 fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
182 if (!fid) {
183
184 if (access == V9FS_ACCESS_SINGLE)
185 return ERR_PTR(-EPERM);
186
187 if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
188 uname = NULL;
189 else
190 uname = v9ses->uname;
191
192 fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
193 v9ses->aname);
194 if (IS_ERR(fid))
195 return fid;
196
197 v9fs_fid_add(dentry->d_sb->s_root, fid);
198 }
199
200 if (dentry->d_sb->s_root == dentry) {
201 refcount_inc(&fid->count);
202 return fid;
203 }
204
205
206
207
208
209 down_read(&v9ses->rename_sem);
210 n = build_path_from_dentry(v9ses, dentry, &wnames);
211 if (n < 0) {
212 fid = ERR_PTR(n);
213 goto err_out;
214 }
215 clone = 1;
216 i = 0;
217 while (i < n) {
218 l = min(n - i, P9_MAXWELEM);
219
220
221
222
223 fid = p9_client_walk(fid, l, &wnames[i], clone);
224 if (IS_ERR(fid)) {
225 if (old_fid) {
226
227
228
229
230
231 p9_client_clunk(old_fid);
232 }
233 kfree(wnames);
234 goto err_out;
235 }
236 old_fid = fid;
237 i += l;
238 clone = 0;
239 }
240 kfree(wnames);
241fid_out:
242 if (!IS_ERR(fid)) {
243 spin_lock(&dentry->d_lock);
244 if (d_unhashed(dentry)) {
245 spin_unlock(&dentry->d_lock);
246 p9_client_clunk(fid);
247 fid = ERR_PTR(-ENOENT);
248 } else {
249 __add_fid(dentry, fid);
250 refcount_inc(&fid->count);
251 spin_unlock(&dentry->d_lock);
252 }
253 }
254err_out:
255 up_read(&v9ses->rename_sem);
256 return fid;
257}
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267
268
269struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
270{
271 kuid_t uid;
272 int any, access;
273 struct v9fs_session_info *v9ses;
274
275 v9ses = v9fs_dentry2v9ses(dentry);
276 access = v9ses->flags & V9FS_ACCESS_MASK;
277 switch (access) {
278 case V9FS_ACCESS_SINGLE:
279 case V9FS_ACCESS_USER:
280 case V9FS_ACCESS_CLIENT:
281 uid = current_fsuid();
282 any = 0;
283 break;
284
285 case V9FS_ACCESS_ANY:
286 uid = v9ses->uid;
287 any = 1;
288 break;
289
290 default:
291 uid = INVALID_UID;
292 any = 0;
293 break;
294 }
295 return v9fs_fid_lookup_with_uid(dentry, uid, any);
296}
297
298struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
299{
300 int err;
301 struct p9_fid *fid, *ofid;
302
303 ofid = v9fs_fid_lookup_with_uid(dentry, GLOBAL_ROOT_UID, 0);
304 fid = clone_fid(ofid);
305 if (IS_ERR(fid))
306 goto error_out;
307 p9_client_clunk(ofid);
308
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311
312
313
314 err = p9_client_open(fid, O_RDWR);
315 if (err < 0) {
316 p9_client_clunk(fid);
317 fid = ERR_PTR(err);
318 goto error_out;
319 }
320error_out:
321 return fid;
322}
323