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8#include <linux/fs.h>
9#include <linux/namei.h>
10#include <linux/dns_resolver.h>
11#include "internal.h"
12
13static atomic_t afs_autocell_ino;
14
15
16
17
18
19
20static int afs_iget5_pseudo_test(struct inode *inode, void *opaque)
21{
22 return 0;
23}
24
25
26
27
28static int afs_iget5_pseudo_set(struct inode *inode, void *opaque)
29{
30 struct afs_super_info *as = AFS_FS_S(inode->i_sb);
31 struct afs_vnode *vnode = AFS_FS_I(inode);
32 struct afs_fid *fid = opaque;
33
34 vnode->volume = as->volume;
35 vnode->fid = *fid;
36 inode->i_ino = fid->vnode;
37 inode->i_generation = fid->unique;
38 return 0;
39}
40
41
42
43
44
45struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
46{
47 struct afs_super_info *as = AFS_FS_S(sb);
48 struct afs_vnode *vnode;
49 struct inode *inode;
50 struct afs_fid fid = {};
51
52 _enter("");
53
54 if (as->volume)
55 fid.vid = as->volume->vid;
56 if (root) {
57 fid.vnode = 1;
58 fid.unique = 1;
59 } else {
60 fid.vnode = atomic_inc_return(&afs_autocell_ino);
61 fid.unique = 0;
62 }
63
64 inode = iget5_locked(sb, fid.vnode,
65 afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
66 if (!inode) {
67 _leave(" = -ENOMEM");
68 return ERR_PTR(-ENOMEM);
69 }
70
71 _debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }",
72 inode, inode->i_ino, fid.vid, fid.vnode, fid.unique);
73
74 vnode = AFS_FS_I(inode);
75
76
77 BUG_ON(!(inode->i_state & I_NEW));
78
79 inode->i_size = 0;
80 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
81 if (root) {
82 inode->i_op = &afs_dynroot_inode_operations;
83 inode->i_fop = &simple_dir_operations;
84 } else {
85 inode->i_op = &afs_autocell_inode_operations;
86 }
87 set_nlink(inode, 2);
88 inode->i_uid = GLOBAL_ROOT_UID;
89 inode->i_gid = GLOBAL_ROOT_GID;
90 inode->i_ctime = inode->i_atime = inode->i_mtime = current_time(inode);
91 inode->i_blocks = 0;
92 inode->i_generation = 0;
93
94 set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
95 if (!root) {
96 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
97 inode->i_flags |= S_AUTOMOUNT;
98 }
99
100 inode->i_flags |= S_NOATIME;
101 unlock_new_inode(inode);
102 _leave(" = %p", inode);
103 return inode;
104}
105
106
107
108
109
110static int afs_probe_cell_name(struct dentry *dentry)
111{
112 struct afs_cell *cell;
113 struct afs_net *net = afs_d2net(dentry);
114 const char *name = dentry->d_name.name;
115 size_t len = dentry->d_name.len;
116 int ret;
117
118
119 if (name[0] == '.') {
120 if (len == 1)
121 return -EINVAL;
122 name++;
123 len--;
124 }
125
126 cell = afs_find_cell(net, name, len, afs_cell_trace_use_probe);
127 if (!IS_ERR(cell)) {
128 afs_unuse_cell(net, cell, afs_cell_trace_unuse_probe);
129 return 0;
130 }
131
132 ret = dns_query(net->net, "afsdb", name, len, "srv=1",
133 NULL, NULL, false);
134 if (ret == -ENODATA)
135 ret = -EDESTADDRREQ;
136 return ret;
137}
138
139
140
141
142
143struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
144{
145 struct afs_vnode *vnode = AFS_FS_I(dir);
146 struct inode *inode;
147 int ret = -ENOENT;
148
149 _enter("%p{%pd}, {%llx:%llu}",
150 dentry, dentry, vnode->fid.vid, vnode->fid.vnode);
151
152 if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
153 goto out;
154
155 ret = afs_probe_cell_name(dentry);
156 if (ret < 0)
157 goto out;
158
159 inode = afs_iget_pseudo_dir(dir->i_sb, false);
160 if (IS_ERR(inode)) {
161 ret = PTR_ERR(inode);
162 goto out;
163 }
164
165 _leave("= %p", inode);
166 return inode;
167
168out:
169 _leave("= %d", ret);
170 return ret == -ENOENT ? NULL : ERR_PTR(ret);
171}
172
173
174
175
176
177static struct dentry *afs_lookup_atcell(struct dentry *dentry)
178{
179 struct afs_cell *cell;
180 struct afs_net *net = afs_d2net(dentry);
181 struct dentry *ret;
182 char *name;
183 int len;
184
185 if (!net->ws_cell)
186 return ERR_PTR(-ENOENT);
187
188 ret = ERR_PTR(-ENOMEM);
189 name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL);
190 if (!name)
191 goto out_p;
192
193 down_read(&net->cells_lock);
194 cell = net->ws_cell;
195 if (cell) {
196 len = cell->name_len;
197 memcpy(name, cell->name, len + 1);
198 }
199 up_read(&net->cells_lock);
200
201 ret = ERR_PTR(-ENOENT);
202 if (!cell)
203 goto out_n;
204
205 ret = lookup_one_len(name, dentry->d_parent, len);
206
207
208
209
210
211out_n:
212 kfree(name);
213out_p:
214 return ret;
215}
216
217
218
219
220static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentry,
221 unsigned int flags)
222{
223 _enter("%pd", dentry);
224
225 ASSERTCMP(d_inode(dentry), ==, NULL);
226
227 if (flags & LOOKUP_CREATE)
228 return ERR_PTR(-EOPNOTSUPP);
229
230 if (dentry->d_name.len >= AFSNAMEMAX) {
231 _leave(" = -ENAMETOOLONG");
232 return ERR_PTR(-ENAMETOOLONG);
233 }
234
235 if (dentry->d_name.len == 5 &&
236 memcmp(dentry->d_name.name, "@cell", 5) == 0)
237 return afs_lookup_atcell(dentry);
238
239 return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
240}
241
242const struct inode_operations afs_dynroot_inode_operations = {
243 .lookup = afs_dynroot_lookup,
244};
245
246
247
248
249static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags)
250{
251 return 1;
252}
253
254
255
256
257
258
259
260static int afs_dynroot_d_delete(const struct dentry *dentry)
261{
262 return d_really_is_positive(dentry);
263}
264
265const struct dentry_operations afs_dynroot_dentry_operations = {
266 .d_revalidate = afs_dynroot_d_revalidate,
267 .d_delete = afs_dynroot_d_delete,
268 .d_release = afs_d_release,
269 .d_automount = afs_d_automount,
270};
271
272
273
274
275
276int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
277{
278 struct super_block *sb = net->dynroot_sb;
279 struct dentry *root, *subdir;
280 int ret;
281
282 if (!sb || atomic_read(&sb->s_active) == 0)
283 return 0;
284
285
286 root = sb->s_root;
287 inode_lock(root->d_inode);
288 subdir = lookup_one_len(cell->name, root, cell->name_len);
289 if (IS_ERR(subdir)) {
290 ret = PTR_ERR(subdir);
291 goto unlock;
292 }
293
294
295 subdir->d_fsdata = (void *)1UL;
296 ret = 0;
297unlock:
298 inode_unlock(root->d_inode);
299 return ret;
300}
301
302
303
304
305
306void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
307{
308 struct super_block *sb = net->dynroot_sb;
309 struct dentry *root, *subdir;
310
311 if (!sb || atomic_read(&sb->s_active) == 0)
312 return;
313
314 root = sb->s_root;
315 inode_lock(root->d_inode);
316
317
318 subdir = try_lookup_one_len(cell->name, root, cell->name_len);
319 if (IS_ERR_OR_NULL(subdir)) {
320 _debug("lookup %ld", PTR_ERR(subdir));
321 goto no_dentry;
322 }
323
324 _debug("rmdir %pd %u", subdir, d_count(subdir));
325
326 if (subdir->d_fsdata) {
327 _debug("unpin %u", d_count(subdir));
328 subdir->d_fsdata = NULL;
329 dput(subdir);
330 }
331 dput(subdir);
332no_dentry:
333 inode_unlock(root->d_inode);
334 _leave("");
335}
336
337
338
339
340int afs_dynroot_populate(struct super_block *sb)
341{
342 struct afs_cell *cell;
343 struct afs_net *net = afs_sb2net(sb);
344 int ret;
345
346 mutex_lock(&net->proc_cells_lock);
347
348 net->dynroot_sb = sb;
349 hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
350 ret = afs_dynroot_mkdir(net, cell);
351 if (ret < 0)
352 goto error;
353 }
354
355 ret = 0;
356out:
357 mutex_unlock(&net->proc_cells_lock);
358 return ret;
359
360error:
361 net->dynroot_sb = NULL;
362 goto out;
363}
364
365
366
367
368
369void afs_dynroot_depopulate(struct super_block *sb)
370{
371 struct afs_net *net = afs_sb2net(sb);
372 struct dentry *root = sb->s_root, *subdir, *tmp;
373
374
375 mutex_lock(&net->proc_cells_lock);
376 if (net->dynroot_sb == sb)
377 net->dynroot_sb = NULL;
378 mutex_unlock(&net->proc_cells_lock);
379
380 if (root) {
381 inode_lock(root->d_inode);
382
383
384 list_for_each_entry_safe(subdir, tmp, &root->d_subdirs, d_child) {
385 if (subdir->d_fsdata) {
386 subdir->d_fsdata = NULL;
387 dput(subdir);
388 }
389 }
390
391 inode_unlock(root->d_inode);
392 }
393}
394