Merge branch 'for-3.3' of git://linux-nfs.org/~bfields/linux
[linux-3.10.git] / fs / nfsd / nfs4recover.c
1 /*
2 *  Copyright (c) 2004 The Regents of the University of Michigan.
3 *  All rights reserved.
4 *
5 *  Andy Adamson <andros@citi.umich.edu>
6 *
7 *  Redistribution and use in source and binary forms, with or without
8 *  modification, are permitted provided that the following conditions
9 *  are met:
10 *
11 *  1. Redistributions of source code must retain the above copyright
12 *     notice, this list of conditions and the following disclaimer.
13 *  2. Redistributions in binary form must reproduce the above copyright
14 *     notice, this list of conditions and the following disclaimer in the
15 *     documentation and/or other materials provided with the distribution.
16 *  3. Neither the name of the University nor the names of its
17 *     contributors may be used to endorse or promote products derived
18 *     from this software without specific prior written permission.
19 *
20 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
21 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
22 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
23 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
27 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 */
33
34 #include <linux/file.h>
35 #include <linux/slab.h>
36 #include <linux/namei.h>
37 #include <linux/crypto.h>
38 #include <linux/sched.h>
39
40 #include "nfsd.h"
41 #include "state.h"
42 #include "vfs.h"
43
44 #define NFSDDBG_FACILITY                NFSDDBG_PROC
45
46 /* Globals */
47 static struct file *rec_file;
48 static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
49
50 static int
51 nfs4_save_creds(const struct cred **original_creds)
52 {
53         struct cred *new;
54
55         new = prepare_creds();
56         if (!new)
57                 return -ENOMEM;
58
59         new->fsuid = 0;
60         new->fsgid = 0;
61         *original_creds = override_creds(new);
62         put_cred(new);
63         return 0;
64 }
65
66 static void
67 nfs4_reset_creds(const struct cred *original)
68 {
69         revert_creds(original);
70 }
71
72 static void
73 md5_to_hex(char *out, char *md5)
74 {
75         int i;
76
77         for (i=0; i<16; i++) {
78                 unsigned char c = md5[i];
79
80                 *out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
81                 *out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
82         }
83         *out = '\0';
84 }
85
86 __be32
87 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
88 {
89         struct xdr_netobj cksum;
90         struct hash_desc desc;
91         struct scatterlist sg;
92         __be32 status = nfserr_jukebox;
93
94         dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
95                         clname->len, clname->data);
96         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
97         desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
98         if (IS_ERR(desc.tfm))
99                 goto out_no_tfm;
100         cksum.len = crypto_hash_digestsize(desc.tfm);
101         cksum.data = kmalloc(cksum.len, GFP_KERNEL);
102         if (cksum.data == NULL)
103                 goto out;
104
105         sg_init_one(&sg, clname->data, clname->len);
106
107         if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
108                 goto out;
109
110         md5_to_hex(dname, cksum.data);
111
112         status = nfs_ok;
113 out:
114         kfree(cksum.data);
115         crypto_free_hash(desc.tfm);
116 out_no_tfm:
117         return status;
118 }
119
120 void nfsd4_create_clid_dir(struct nfs4_client *clp)
121 {
122         const struct cred *original_cred;
123         char *dname = clp->cl_recdir;
124         struct dentry *dir, *dentry;
125         int status;
126
127         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
128
129         if (clp->cl_firststate)
130                 return;
131         clp->cl_firststate = 1;
132         if (!rec_file)
133                 return;
134         status = nfs4_save_creds(&original_cred);
135         if (status < 0)
136                 return;
137
138         dir = rec_file->f_path.dentry;
139         /* lock the parent */
140         mutex_lock(&dir->d_inode->i_mutex);
141
142         dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
143         if (IS_ERR(dentry)) {
144                 status = PTR_ERR(dentry);
145                 goto out_unlock;
146         }
147         if (dentry->d_inode)
148                 /*
149                  * In the 4.1 case, where we're called from
150                  * reclaim_complete(), records from the previous reboot
151                  * may still be left, so this is OK.
152                  *
153                  * In the 4.0 case, we should never get here; but we may
154                  * as well be forgiving and just succeed silently.
155                  */
156                 goto out_put;
157         status = mnt_want_write_file(rec_file);
158         if (status)
159                 goto out_put;
160         status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
161         mnt_drop_write_file(rec_file);
162 out_put:
163         dput(dentry);
164 out_unlock:
165         mutex_unlock(&dir->d_inode->i_mutex);
166         if (status == 0)
167                 vfs_fsync(rec_file, 0);
168         else
169                 printk(KERN_ERR "NFSD: failed to write recovery record"
170                                 " (err %d); please check that %s exists"
171                                 " and is writeable", status,
172                                 user_recovery_dirname);
173         nfs4_reset_creds(original_cred);
174 }
175
176 typedef int (recdir_func)(struct dentry *, struct dentry *);
177
178 struct name_list {
179         char name[HEXDIR_LEN];
180         struct list_head list;
181 };
182
183 static int
184 nfsd4_build_namelist(void *arg, const char *name, int namlen,
185                 loff_t offset, u64 ino, unsigned int d_type)
186 {
187         struct list_head *names = arg;
188         struct name_list *entry;
189
190         if (namlen != HEXDIR_LEN - 1)
191                 return 0;
192         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
193         if (entry == NULL)
194                 return -ENOMEM;
195         memcpy(entry->name, name, HEXDIR_LEN - 1);
196         entry->name[HEXDIR_LEN - 1] = '\0';
197         list_add(&entry->list, names);
198         return 0;
199 }
200
201 static int
202 nfsd4_list_rec_dir(recdir_func *f)
203 {
204         const struct cred *original_cred;
205         struct dentry *dir = rec_file->f_path.dentry;
206         LIST_HEAD(names);
207         int status;
208
209         status = nfs4_save_creds(&original_cred);
210         if (status < 0)
211                 return status;
212
213         status = vfs_llseek(rec_file, 0, SEEK_SET);
214         if (status < 0) {
215                 nfs4_reset_creds(original_cred);
216                 return status;
217         }
218
219         status = vfs_readdir(rec_file, nfsd4_build_namelist, &names);
220         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
221         while (!list_empty(&names)) {
222                 struct name_list *entry;
223                 entry = list_entry(names.next, struct name_list, list);
224                 if (!status) {
225                         struct dentry *dentry;
226                         dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
227                         if (IS_ERR(dentry)) {
228                                 status = PTR_ERR(dentry);
229                                 break;
230                         }
231                         status = f(dir, dentry);
232                         dput(dentry);
233                 }
234                 list_del(&entry->list);
235                 kfree(entry);
236         }
237         mutex_unlock(&dir->d_inode->i_mutex);
238         nfs4_reset_creds(original_cred);
239         return status;
240 }
241
242 static int
243 nfsd4_unlink_clid_dir(char *name, int namlen)
244 {
245         struct dentry *dir, *dentry;
246         int status;
247
248         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
249
250         dir = rec_file->f_path.dentry;
251         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
252         dentry = lookup_one_len(name, dir, namlen);
253         if (IS_ERR(dentry)) {
254                 status = PTR_ERR(dentry);
255                 goto out_unlock;
256         }
257         status = -ENOENT;
258         if (!dentry->d_inode)
259                 goto out;
260         status = vfs_rmdir(dir->d_inode, dentry);
261 out:
262         dput(dentry);
263 out_unlock:
264         mutex_unlock(&dir->d_inode->i_mutex);
265         return status;
266 }
267
268 void
269 nfsd4_remove_clid_dir(struct nfs4_client *clp)
270 {
271         const struct cred *original_cred;
272         int status;
273
274         if (!rec_file || !clp->cl_firststate)
275                 return;
276
277         status = mnt_want_write_file(rec_file);
278         if (status)
279                 goto out;
280         clp->cl_firststate = 0;
281
282         status = nfs4_save_creds(&original_cred);
283         if (status < 0)
284                 goto out;
285
286         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
287         nfs4_reset_creds(original_cred);
288         if (status == 0)
289                 vfs_fsync(rec_file, 0);
290         mnt_drop_write_file(rec_file);
291 out:
292         if (status)
293                 printk("NFSD: Failed to remove expired client state directory"
294                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
295         return;
296 }
297
298 static int
299 purge_old(struct dentry *parent, struct dentry *child)
300 {
301         int status;
302
303         if (nfs4_has_reclaimed_state(child->d_name.name, false))
304                 return 0;
305
306         status = vfs_rmdir(parent->d_inode, child);
307         if (status)
308                 printk("failed to remove client recovery directory %s\n",
309                                 child->d_name.name);
310         /* Keep trying, success or failure: */
311         return 0;
312 }
313
314 void
315 nfsd4_recdir_purge_old(void) {
316         int status;
317
318         if (!rec_file)
319                 return;
320         status = mnt_want_write_file(rec_file);
321         if (status)
322                 goto out;
323         status = nfsd4_list_rec_dir(purge_old);
324         if (status == 0)
325                 vfs_fsync(rec_file, 0);
326         mnt_drop_write_file(rec_file);
327 out:
328         if (status)
329                 printk("nfsd4: failed to purge old clients from recovery"
330                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
331 }
332
333 static int
334 load_recdir(struct dentry *parent, struct dentry *child)
335 {
336         if (child->d_name.len != HEXDIR_LEN - 1) {
337                 printk("nfsd4: illegal name %s in recovery directory\n",
338                                 child->d_name.name);
339                 /* Keep trying; maybe the others are OK: */
340                 return 0;
341         }
342         nfs4_client_to_reclaim(child->d_name.name);
343         return 0;
344 }
345
346 int
347 nfsd4_recdir_load(void) {
348         int status;
349
350         if (!rec_file)
351                 return 0;
352
353         status = nfsd4_list_rec_dir(load_recdir);
354         if (status)
355                 printk("nfsd4: failed loading clients from recovery"
356                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
357         return status;
358 }
359
360 /*
361  * Hold reference to the recovery directory.
362  */
363
364 void
365 nfsd4_init_recdir()
366 {
367         const struct cred *original_cred;
368         int status;
369
370         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
371                         user_recovery_dirname);
372
373         BUG_ON(rec_file);
374
375         status = nfs4_save_creds(&original_cred);
376         if (status < 0) {
377                 printk("NFSD: Unable to change credentials to find recovery"
378                        " directory: error %d\n",
379                        status);
380                 return;
381         }
382
383         rec_file = filp_open(user_recovery_dirname, O_RDONLY | O_DIRECTORY, 0);
384         if (IS_ERR(rec_file)) {
385                 printk("NFSD: unable to find recovery directory %s\n",
386                                 user_recovery_dirname);
387                 rec_file = NULL;
388         }
389
390         nfs4_reset_creds(original_cred);
391 }
392
393 void
394 nfsd4_shutdown_recdir(void)
395 {
396         if (!rec_file)
397                 return;
398         fput(rec_file);
399         rec_file = NULL;
400 }
401
402 /*
403  * Change the NFSv4 recovery directory to recdir.
404  */
405 int
406 nfs4_reset_recoverydir(char *recdir)
407 {
408         int status;
409         struct path path;
410
411         status = kern_path(recdir, LOOKUP_FOLLOW, &path);
412         if (status)
413                 return status;
414         status = -ENOTDIR;
415         if (S_ISDIR(path.dentry->d_inode->i_mode)) {
416                 strcpy(user_recovery_dirname, recdir);
417                 status = 0;
418         }
419         path_put(&path);
420         return status;
421 }
422
423 char *
424 nfs4_recoverydir(void)
425 {
426         return user_recovery_dirname;
427 }