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/fs/nfsd/nfs4recover.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 392 lines | 297 code | 56 blank | 39 comment | 46 complexity | 27f16d6aeb479659d95eff0925709e17 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  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 */
 47static struct file *rec_file;
 48
 49static int
 50nfs4_save_creds(const struct cred **original_creds)
 51{
 52	struct cred *new;
 53
 54	new = prepare_creds();
 55	if (!new)
 56		return -ENOMEM;
 57
 58	new->fsuid = 0;
 59	new->fsgid = 0;
 60	*original_creds = override_creds(new);
 61	put_cred(new);
 62	return 0;
 63}
 64
 65static void
 66nfs4_reset_creds(const struct cred *original)
 67{
 68	revert_creds(original);
 69}
 70
 71static void
 72md5_to_hex(char *out, char *md5)
 73{
 74	int i;
 75
 76	for (i=0; i<16; i++) {
 77		unsigned char c = md5[i];
 78
 79		*out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
 80		*out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
 81	}
 82	*out = '\0';
 83}
 84
 85__be32
 86nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
 87{
 88	struct xdr_netobj cksum;
 89	struct hash_desc desc;
 90	struct scatterlist sg;
 91	__be32 status = nfserr_jukebox;
 92
 93	dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
 94			clname->len, clname->data);
 95	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 96	desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
 97	if (IS_ERR(desc.tfm))
 98		goto out_no_tfm;
 99	cksum.len = crypto_hash_digestsize(desc.tfm);
100	cksum.data = kmalloc(cksum.len, GFP_KERNEL);
101	if (cksum.data == NULL)
102 		goto out;
103
104	sg_init_one(&sg, clname->data, clname->len);
105
106	if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
107		goto out;
108
109	md5_to_hex(dname, cksum.data);
110
111	status = nfs_ok;
112out:
113	kfree(cksum.data);
114	crypto_free_hash(desc.tfm);
115out_no_tfm:
116	return status;
117}
118
119int
120nfsd4_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 (!rec_file || clp->cl_firststate)
130		return 0;
131
132	status = nfs4_save_creds(&original_cred);
133	if (status < 0)
134		return status;
135
136	dir = rec_file->f_path.dentry;
137	/* lock the parent */
138	mutex_lock(&dir->d_inode->i_mutex);
139
140	dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
141	if (IS_ERR(dentry)) {
142		status = PTR_ERR(dentry);
143		goto out_unlock;
144	}
145	status = -EEXIST;
146	if (dentry->d_inode) {
147		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
148		goto out_put;
149	}
150	status = mnt_want_write(rec_file->f_path.mnt);
151	if (status)
152		goto out_put;
153	status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
154	mnt_drop_write(rec_file->f_path.mnt);
155out_put:
156	dput(dentry);
157out_unlock:
158	mutex_unlock(&dir->d_inode->i_mutex);
159	if (status == 0) {
160		clp->cl_firststate = 1;
161		vfs_fsync(rec_file, 0);
162	}
163	nfs4_reset_creds(original_cred);
164	dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
165	return status;
166}
167
168typedef int (recdir_func)(struct dentry *, struct dentry *);
169
170struct name_list {
171	char name[HEXDIR_LEN];
172	struct list_head list;
173};
174
175static int
176nfsd4_build_namelist(void *arg, const char *name, int namlen,
177		loff_t offset, u64 ino, unsigned int d_type)
178{
179	struct list_head *names = arg;
180	struct name_list *entry;
181
182	if (namlen != HEXDIR_LEN - 1)
183		return 0;
184	entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
185	if (entry == NULL)
186		return -ENOMEM;
187	memcpy(entry->name, name, HEXDIR_LEN - 1);
188	entry->name[HEXDIR_LEN - 1] = '\0';
189	list_add(&entry->list, names);
190	return 0;
191}
192
193static int
194nfsd4_list_rec_dir(recdir_func *f)
195{
196	const struct cred *original_cred;
197	struct dentry *dir = rec_file->f_path.dentry;
198	LIST_HEAD(names);
199	int status;
200
201	status = nfs4_save_creds(&original_cred);
202	if (status < 0)
203		return status;
204
205	status = vfs_llseek(rec_file, 0, SEEK_SET);
206	if (status < 0) {
207		nfs4_reset_creds(original_cred);
208		return status;
209	}
210
211	status = vfs_readdir(rec_file, nfsd4_build_namelist, &names);
212	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
213	while (!list_empty(&names)) {
214		struct name_list *entry;
215		entry = list_entry(names.next, struct name_list, list);
216		if (!status) {
217			struct dentry *dentry;
218			dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
219			if (IS_ERR(dentry)) {
220				status = PTR_ERR(dentry);
221				break;
222			}
223			status = f(dir, dentry);
224			dput(dentry);
225		}
226		list_del(&entry->list);
227		kfree(entry);
228	}
229	mutex_unlock(&dir->d_inode->i_mutex);
230	nfs4_reset_creds(original_cred);
231	return status;
232}
233
234static int
235nfsd4_unlink_clid_dir(char *name, int namlen)
236{
237	struct dentry *dir, *dentry;
238	int status;
239
240	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
241
242	dir = rec_file->f_path.dentry;
243	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
244	dentry = lookup_one_len(name, dir, namlen);
245	if (IS_ERR(dentry)) {
246		status = PTR_ERR(dentry);
247		goto out_unlock;
248	}
249	status = -ENOENT;
250	if (!dentry->d_inode)
251		goto out;
252	status = vfs_rmdir(dir->d_inode, dentry);
253out:
254	dput(dentry);
255out_unlock:
256	mutex_unlock(&dir->d_inode->i_mutex);
257	return status;
258}
259
260void
261nfsd4_remove_clid_dir(struct nfs4_client *clp)
262{
263	const struct cred *original_cred;
264	int status;
265
266	if (!rec_file || !clp->cl_firststate)
267		return;
268
269	status = mnt_want_write(rec_file->f_path.mnt);
270	if (status)
271		goto out;
272	clp->cl_firststate = 0;
273
274	status = nfs4_save_creds(&original_cred);
275	if (status < 0)
276		goto out;
277
278	status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
279	nfs4_reset_creds(original_cred);
280	if (status == 0)
281		vfs_fsync(rec_file, 0);
282	mnt_drop_write(rec_file->f_path.mnt);
283out:
284	if (status)
285		printk("NFSD: Failed to remove expired client state directory"
286				" %.*s\n", HEXDIR_LEN, clp->cl_recdir);
287	return;
288}
289
290static int
291purge_old(struct dentry *parent, struct dentry *child)
292{
293	int status;
294
295	if (nfs4_has_reclaimed_state(child->d_name.name, false))
296		return 0;
297
298	status = vfs_rmdir(parent->d_inode, child);
299	if (status)
300		printk("failed to remove client recovery directory %s\n",
301				child->d_name.name);
302	/* Keep trying, success or failure: */
303	return 0;
304}
305
306void
307nfsd4_recdir_purge_old(void) {
308	int status;
309
310	if (!rec_file)
311		return;
312	status = mnt_want_write(rec_file->f_path.mnt);
313	if (status)
314		goto out;
315	status = nfsd4_list_rec_dir(purge_old);
316	if (status == 0)
317		vfs_fsync(rec_file, 0);
318	mnt_drop_write(rec_file->f_path.mnt);
319out:
320	if (status)
321		printk("nfsd4: failed to purge old clients from recovery"
322			" directory %s\n", rec_file->f_path.dentry->d_name.name);
323}
324
325static int
326load_recdir(struct dentry *parent, struct dentry *child)
327{
328	if (child->d_name.len != HEXDIR_LEN - 1) {
329		printk("nfsd4: illegal name %s in recovery directory\n",
330				child->d_name.name);
331		/* Keep trying; maybe the others are OK: */
332		return 0;
333	}
334	nfs4_client_to_reclaim(child->d_name.name);
335	return 0;
336}
337
338int
339nfsd4_recdir_load(void) {
340	int status;
341
342	if (!rec_file)
343		return 0;
344
345	status = nfsd4_list_rec_dir(load_recdir);
346	if (status)
347		printk("nfsd4: failed loading clients from recovery"
348			" directory %s\n", rec_file->f_path.dentry->d_name.name);
349	return status;
350}
351
352/*
353 * Hold reference to the recovery directory.
354 */
355
356void
357nfsd4_init_recdir(char *rec_dirname)
358{
359	const struct cred *original_cred;
360	int status;
361
362	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
363			rec_dirname);
364
365	BUG_ON(rec_file);
366
367	status = nfs4_save_creds(&original_cred);
368	if (status < 0) {
369		printk("NFSD: Unable to change credentials to find recovery"
370		       " directory: error %d\n",
371		       status);
372		return;
373	}
374
375	rec_file = filp_open(rec_dirname, O_RDONLY | O_DIRECTORY, 0);
376	if (IS_ERR(rec_file)) {
377		printk("NFSD: unable to find recovery directory %s\n",
378				rec_dirname);
379		rec_file = NULL;
380	}
381
382	nfs4_reset_creds(original_cred);
383}
384
385void
386nfsd4_shutdown_recdir(void)
387{
388	if (!rec_file)
389		return;
390	fput(rec_file);
391	rec_file = NULL;
392}