xref: /freebsd/sys/geom/mirror/g_mirror.h (revision 6e778a7efdc0e804471750157f6bacd1ef7d1580)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5  * All rights reserved.
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  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #ifndef	_G_MIRROR_H_
32 #define	_G_MIRROR_H_
33 
34 #include <sys/endian.h>
35 #include <sys/md5.h>
36 
37 #define	G_MIRROR_CLASS_NAME	"MIRROR"
38 
39 #define	G_MIRROR_MAGIC		"GEOM::MIRROR"
40 /*
41  * Version history:
42  * 0 - Initial version number.
43  * 1 - Added 'prefer' balance algorithm.
44  * 2 - Added md_genid field to metadata.
45  * 3 - Added md_provsize field to metadata.
46  * 4 - Added 'no failure synchronization' flag.
47  */
48 #define	G_MIRROR_VERSION	4
49 
50 #define	G_MIRROR_BALANCE_NONE		0
51 #define	G_MIRROR_BALANCE_ROUND_ROBIN	1
52 #define	G_MIRROR_BALANCE_LOAD		2
53 #define	G_MIRROR_BALANCE_SPLIT		3
54 #define	G_MIRROR_BALANCE_PREFER		4
55 #define	G_MIRROR_BALANCE_MIN		G_MIRROR_BALANCE_NONE
56 #define	G_MIRROR_BALANCE_MAX		G_MIRROR_BALANCE_PREFER
57 
58 #define	G_MIRROR_DISK_FLAG_DIRTY		0x0000000000000001ULL
59 #define	G_MIRROR_DISK_FLAG_SYNCHRONIZING	0x0000000000000002ULL
60 #define	G_MIRROR_DISK_FLAG_FORCE_SYNC		0x0000000000000004ULL
61 #define	G_MIRROR_DISK_FLAG_INACTIVE		0x0000000000000008ULL
62 #define	G_MIRROR_DISK_FLAG_HARDCODED		0x0000000000000010ULL
63 #define	G_MIRROR_DISK_FLAG_BROKEN		0x0000000000000020ULL
64 #define	G_MIRROR_DISK_FLAG_CANDELETE		0x0000000000000040ULL
65 #define	G_MIRROR_DISK_FLAG_MASK		(G_MIRROR_DISK_FLAG_DIRTY |	\
66 					 G_MIRROR_DISK_FLAG_SYNCHRONIZING | \
67 					 G_MIRROR_DISK_FLAG_FORCE_SYNC | \
68 					 G_MIRROR_DISK_FLAG_INACTIVE | \
69 					 G_MIRROR_DISK_FLAG_CANDELETE)
70 
71 #define	G_MIRROR_DEVICE_FLAG_NOAUTOSYNC	0x0000000000000001ULL
72 #define	G_MIRROR_DEVICE_FLAG_NOFAILSYNC	0x0000000000000002ULL
73 #define	G_MIRROR_DEVICE_FLAG_MASK	(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC | \
74 					 G_MIRROR_DEVICE_FLAG_NOFAILSYNC)
75 
76 #ifdef _KERNEL
77 extern int g_mirror_debug;
78 
79 #define	G_MIRROR_DEBUG(lvl, ...)	do {				\
80 	if (g_mirror_debug >= (lvl)) {					\
81 		printf("GEOM_MIRROR");					\
82 		if (g_mirror_debug > 0)					\
83 			printf("[%u]", lvl);				\
84 		printf(": ");						\
85 		printf(__VA_ARGS__);					\
86 		printf("\n");						\
87 	}								\
88 } while (0)
89 #define	G_MIRROR_LOGREQ(lvl, bp, ...)	do {				\
90 	if (g_mirror_debug >= (lvl)) {					\
91 		printf("GEOM_MIRROR");					\
92 		if (g_mirror_debug > 0)					\
93 			printf("[%u]", lvl);				\
94 		printf(": ");						\
95 		printf(__VA_ARGS__);					\
96 		printf(" ");						\
97 		g_print_bio(bp);					\
98 		printf("\n");						\
99 	}								\
100 } while (0)
101 
102 #define	G_MIRROR_BIO_FLAG_REGULAR	0x01
103 #define	G_MIRROR_BIO_FLAG_SYNC		0x02
104 
105 /*
106  * Informations needed for synchronization.
107  */
108 struct g_mirror_disk_sync {
109 	struct g_consumer *ds_consumer;	/* Consumer connected to our mirror. */
110 	off_t		  ds_offset;	/* Offset of next request to send. */
111 	off_t		  ds_offset_done; /* Offset of already synchronized
112 					   region. */
113 	time_t		  ds_update_ts; /* Time of last metadata update. */
114 	u_int		  ds_syncid;	/* Disk's synchronization ID. */
115 	u_int		  ds_inflight;	/* Number of in-flight sync requests. */
116 	struct bio	**ds_bios;	/* BIOs for synchronization I/O. */
117 };
118 
119 /*
120  * Informations needed for synchronization.
121  */
122 struct g_mirror_device_sync {
123 	struct g_geom	*ds_geom;	/* Synchronization geom. */
124 	u_int		 ds_ndisks;	/* Number of disks in SYNCHRONIZING
125 					   state. */
126 };
127 
128 #define	G_MIRROR_DISK_STATE_NONE		0
129 #define	G_MIRROR_DISK_STATE_NEW			1
130 #define	G_MIRROR_DISK_STATE_ACTIVE		2
131 #define	G_MIRROR_DISK_STATE_STALE		3
132 #define	G_MIRROR_DISK_STATE_SYNCHRONIZING	4
133 #define	G_MIRROR_DISK_STATE_DISCONNECTED	5
134 #define	G_MIRROR_DISK_STATE_DESTROY		6
135 struct g_mirror_disk {
136 	uint32_t	 d_id;		/* Disk ID. */
137 	struct g_consumer *d_consumer;	/* Consumer. */
138 	struct g_mirror_softc	*d_softc; /* Back-pointer to softc. */
139 	int		 d_state;	/* Disk state. */
140 	u_int		 d_priority;	/* Disk priority. */
141 	u_int		 load;		/* Averaged queue length */
142 	off_t		 d_last_offset;	/* Last read offset */
143 	uint64_t	 d_flags;	/* Additional flags. */
144 	u_int		 d_genid;	/* Disk's generation ID. */
145 	struct g_mirror_disk_sync d_sync;/* Sync information. */
146 	LIST_ENTRY(g_mirror_disk) d_next;
147 };
148 #define	d_name	d_consumer->provider->name
149 
150 #define	G_MIRROR_EVENT_DONTWAIT	0x1
151 #define	G_MIRROR_EVENT_WAIT	0x2
152 #define	G_MIRROR_EVENT_DEVICE	0x4
153 #define	G_MIRROR_EVENT_DONE	0x8
154 struct g_mirror_event {
155 	struct g_mirror_disk	*e_disk;
156 	int			 e_state;
157 	int			 e_flags;
158 	int			 e_error;
159 	TAILQ_ENTRY(g_mirror_event) e_next;
160 };
161 
162 #define	G_MIRROR_DEVICE_FLAG_DESTROY	0x0100000000000000ULL
163 #define	G_MIRROR_DEVICE_FLAG_DRAIN	0x0200000000000000ULL
164 #define	G_MIRROR_DEVICE_FLAG_CLOSEWAIT	0x0400000000000000ULL
165 #define	G_MIRROR_DEVICE_FLAG_TASTING	0x0800000000000000ULL
166 #define	G_MIRROR_DEVICE_FLAG_WIPE	0x1000000000000000ULL
167 
168 #define	G_MIRROR_DEVICE_STATE_STARTING		0
169 #define	G_MIRROR_DEVICE_STATE_RUNNING		1
170 
171 #define	G_MIRROR_TYPE_MANUAL	0
172 #define	G_MIRROR_TYPE_AUTOMATIC	1
173 
174 /* Bump syncid on first write. */
175 #define	G_MIRROR_BUMP_SYNCID		0x1
176 /* Bump genid immediately. */
177 #define	G_MIRROR_BUMP_GENID		0x2
178 /* Bump syncid immediately. */
179 #define	G_MIRROR_BUMP_SYNCID_NOW	0x4
180 struct g_mirror_softc {
181 	u_int		sc_type;	/* Device type (manual/automatic). */
182 	u_int		sc_state;	/* Device state. */
183 	uint32_t	sc_slice;	/* Slice size. */
184 	uint8_t		sc_balance;	/* Balance algorithm. */
185 	uint64_t	sc_mediasize;	/* Device size. */
186 	uint32_t	sc_sectorsize;	/* Sector size. */
187 	uint64_t	sc_flags;	/* Additional flags. */
188 
189 	struct g_geom	*sc_geom;
190 	struct g_provider *sc_provider;
191 	int		sc_provider_open;
192 
193 	uint32_t	sc_id;		/* Mirror unique ID. */
194 
195 	struct sx	 sc_lock;
196 	struct bio_queue_head sc_queue;
197 	struct mtx	 sc_queue_mtx;
198 	struct proc	*sc_worker;
199 	struct bio_queue_head sc_regular_delayed; /* Delayed I/O requests due
200 						     collision with sync
201 						     requests. */
202 	struct bio_queue_head sc_inflight; /* In-flight regular write
203 					      requests. */
204 	struct bio_queue_head sc_sync_delayed; /* Delayed sync requests due
205 						  collision with regular
206 						  requests. */
207 
208 	LIST_HEAD(, g_mirror_disk) sc_disks;
209 	u_int		sc_ndisks;	/* Number of disks. */
210 	struct g_mirror_disk *sc_hint;
211 
212 	u_int		sc_genid;	/* Generation ID. */
213 	u_int		sc_syncid;	/* Synchronization ID. */
214 	int		sc_bump_id;
215 	struct g_mirror_device_sync sc_sync;
216 	int		sc_idle;	/* DIRTY flags removed. */
217 	time_t		sc_last_write;
218 	u_int		sc_writes;
219 	u_int		sc_refcnt;	/* Number of softc references */
220 
221 	TAILQ_HEAD(, g_mirror_event) sc_events;
222 	struct mtx	sc_events_mtx;
223 
224 	struct callout	sc_callout;
225 
226 	struct root_hold_token *sc_rootmount;
227 
228 	struct mtx	 sc_done_mtx;
229 };
230 #define	sc_name	sc_geom->name
231 
232 struct g_mirror_metadata;
233 
234 u_int g_mirror_ndisks(struct g_mirror_softc *sc, int state);
235 struct g_geom * g_mirror_create(struct g_class *mp,
236     const struct g_mirror_metadata *md, u_int type);
237 #define	G_MIRROR_DESTROY_SOFT		0
238 #define	G_MIRROR_DESTROY_DELAYED	1
239 #define	G_MIRROR_DESTROY_HARD		2
240 int g_mirror_destroy(struct g_mirror_softc *sc, int how);
241 int g_mirror_event_send(void *arg, int state, int flags);
242 struct g_mirror_metadata;
243 int g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
244     struct g_mirror_metadata *md);
245 int g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md);
246 void g_mirror_fill_metadata(struct g_mirror_softc *sc,
247     struct g_mirror_disk *disk, struct g_mirror_metadata *md);
248 void g_mirror_update_metadata(struct g_mirror_disk *disk);
249 
250 g_ctl_req_t g_mirror_config;
251 #endif	/* _KERNEL */
252 
253 struct g_mirror_metadata {
254 	char		md_magic[16];	/* Magic value. */
255 	uint32_t	md_version;	/* Version number. */
256 	char		md_name[16];	/* Mirror name. */
257 	uint32_t	md_mid;		/* Mirror unique ID. */
258 	uint32_t	md_did;		/* Disk unique ID. */
259 	uint8_t		md_all;		/* Number of disks in mirror. */
260 	uint32_t	md_genid;	/* Generation ID. */
261 	uint32_t	md_syncid;	/* Synchronization ID. */
262 	uint8_t		md_priority;	/* Disk priority. */
263 	uint32_t	md_slice;	/* Slice size. */
264 	uint8_t		md_balance;	/* Balance type. */
265 	uint64_t	md_mediasize;	/* Size of the smallest
266 					   disk in mirror. */
267 	uint32_t	md_sectorsize;	/* Sector size. */
268 	uint64_t	md_sync_offset;	/* Synchronized offset. */
269 	uint64_t	md_mflags;	/* Additional mirror flags. */
270 	uint64_t	md_dflags;	/* Additional disk flags. */
271 	char		md_provider[16]; /* Hardcoded provider. */
272 	uint64_t	md_provsize;	/* Provider's size. */
273 	u_char		md_hash[16];	/* MD5 hash. */
274 };
275 static __inline void
276 mirror_metadata_encode(struct g_mirror_metadata *md, u_char *data)
277 {
278 	MD5_CTX ctx;
279 
280 	bcopy(md->md_magic, data, 16);
281 	le32enc(data + 16, md->md_version);
282 	bcopy(md->md_name, data + 20, 16);
283 	le32enc(data + 36, md->md_mid);
284 	le32enc(data + 40, md->md_did);
285 	*(data + 44) = md->md_all;
286 	le32enc(data + 45, md->md_genid);
287 	le32enc(data + 49, md->md_syncid);
288 	*(data + 53) = md->md_priority;
289 	le32enc(data + 54, md->md_slice);
290 	*(data + 58) = md->md_balance;
291 	le64enc(data + 59, md->md_mediasize);
292 	le32enc(data + 67, md->md_sectorsize);
293 	le64enc(data + 71, md->md_sync_offset);
294 	le64enc(data + 79, md->md_mflags);
295 	le64enc(data + 87, md->md_dflags);
296 	bcopy(md->md_provider, data + 95, 16);
297 	le64enc(data + 111, md->md_provsize);
298 	MD5Init(&ctx);
299 	MD5Update(&ctx, data, 119);
300 	MD5Final(md->md_hash, &ctx);
301 	bcopy(md->md_hash, data + 119, 16);
302 }
303 static __inline int
304 mirror_metadata_decode_v0v1(const u_char *data, struct g_mirror_metadata *md)
305 {
306 	MD5_CTX ctx;
307 
308 	bcopy(data + 20, md->md_name, 16);
309 	md->md_mid = le32dec(data + 36);
310 	md->md_did = le32dec(data + 40);
311 	md->md_all = *(data + 44);
312 	md->md_syncid = le32dec(data + 45);
313 	md->md_priority = *(data + 49);
314 	md->md_slice = le32dec(data + 50);
315 	md->md_balance = *(data + 54);
316 	md->md_mediasize = le64dec(data + 55);
317 	md->md_sectorsize = le32dec(data + 63);
318 	md->md_sync_offset = le64dec(data + 67);
319 	md->md_mflags = le64dec(data + 75);
320 	md->md_dflags = le64dec(data + 83);
321 	bcopy(data + 91, md->md_provider, 16);
322 	bcopy(data + 107, md->md_hash, 16);
323 	MD5Init(&ctx);
324 	MD5Update(&ctx, data, 107);
325 	MD5Final(md->md_hash, &ctx);
326 	if (bcmp(md->md_hash, data + 107, 16) != 0)
327 		return (EINVAL);
328 
329 	/* New fields. */
330 	md->md_genid = 0;
331 	md->md_provsize = 0;
332 
333 	return (0);
334 }
335 static __inline int
336 mirror_metadata_decode_v2(const u_char *data, struct g_mirror_metadata *md)
337 {
338 	MD5_CTX ctx;
339 
340 	bcopy(data + 20, md->md_name, 16);
341 	md->md_mid = le32dec(data + 36);
342 	md->md_did = le32dec(data + 40);
343 	md->md_all = *(data + 44);
344 	md->md_genid = le32dec(data + 45);
345 	md->md_syncid = le32dec(data + 49);
346 	md->md_priority = *(data + 53);
347 	md->md_slice = le32dec(data + 54);
348 	md->md_balance = *(data + 58);
349 	md->md_mediasize = le64dec(data + 59);
350 	md->md_sectorsize = le32dec(data + 67);
351 	md->md_sync_offset = le64dec(data + 71);
352 	md->md_mflags = le64dec(data + 79);
353 	md->md_dflags = le64dec(data + 87);
354 	bcopy(data + 95, md->md_provider, 16);
355 	bcopy(data + 111, md->md_hash, 16);
356 	MD5Init(&ctx);
357 	MD5Update(&ctx, data, 111);
358 	MD5Final(md->md_hash, &ctx);
359 	if (bcmp(md->md_hash, data + 111, 16) != 0)
360 		return (EINVAL);
361 
362 	/* New fields. */
363 	md->md_provsize = 0;
364 
365 	return (0);
366 }
367 static __inline int
368 mirror_metadata_decode_v3v4(const u_char *data, struct g_mirror_metadata *md)
369 {
370 	MD5_CTX ctx;
371 
372 	bcopy(data + 20, md->md_name, 16);
373 	md->md_mid = le32dec(data + 36);
374 	md->md_did = le32dec(data + 40);
375 	md->md_all = *(data + 44);
376 	md->md_genid = le32dec(data + 45);
377 	md->md_syncid = le32dec(data + 49);
378 	md->md_priority = *(data + 53);
379 	md->md_slice = le32dec(data + 54);
380 	md->md_balance = *(data + 58);
381 	md->md_mediasize = le64dec(data + 59);
382 	md->md_sectorsize = le32dec(data + 67);
383 	md->md_sync_offset = le64dec(data + 71);
384 	md->md_mflags = le64dec(data + 79);
385 	md->md_dflags = le64dec(data + 87);
386 	bcopy(data + 95, md->md_provider, 16);
387 	md->md_provsize = le64dec(data + 111);
388 	bcopy(data + 119, md->md_hash, 16);
389 	MD5Init(&ctx);
390 	MD5Update(&ctx, data, 119);
391 	MD5Final(md->md_hash, &ctx);
392 	if (bcmp(md->md_hash, data + 119, 16) != 0)
393 		return (EINVAL);
394 	return (0);
395 }
396 static __inline int
397 mirror_metadata_decode(const u_char *data, struct g_mirror_metadata *md)
398 {
399 	int error;
400 
401 	bcopy(data, md->md_magic, 16);
402 	md->md_version = le32dec(data + 16);
403 	switch (md->md_version) {
404 	case 0:
405 	case 1:
406 		error = mirror_metadata_decode_v0v1(data, md);
407 		break;
408 	case 2:
409 		error = mirror_metadata_decode_v2(data, md);
410 		break;
411 	case 3:
412 	case 4:
413 		error = mirror_metadata_decode_v3v4(data, md);
414 		break;
415 	default:
416 		error = EINVAL;
417 		break;
418 	}
419 	return (error);
420 }
421 
422 static __inline const char *
423 balance_name(u_int balance)
424 {
425 	static const char *algorithms[] = {
426 		[G_MIRROR_BALANCE_NONE] = "none",
427 		[G_MIRROR_BALANCE_ROUND_ROBIN] = "round-robin",
428 		[G_MIRROR_BALANCE_LOAD] = "load",
429 		[G_MIRROR_BALANCE_SPLIT] = "split",
430 		[G_MIRROR_BALANCE_PREFER] = "prefer",
431 		[G_MIRROR_BALANCE_MAX + 1] = "unknown"
432 	};
433 
434 	if (balance > G_MIRROR_BALANCE_MAX)
435 		balance = G_MIRROR_BALANCE_MAX + 1;
436 
437 	return (algorithms[balance]);
438 }
439 
440 static __inline int
441 balance_id(const char *name)
442 {
443 	static const char *algorithms[] = {
444 		[G_MIRROR_BALANCE_NONE] = "none",
445 		[G_MIRROR_BALANCE_ROUND_ROBIN] = "round-robin",
446 		[G_MIRROR_BALANCE_LOAD] = "load",
447 		[G_MIRROR_BALANCE_SPLIT] = "split",
448 		[G_MIRROR_BALANCE_PREFER] = "prefer"
449 	};
450 	int n;
451 
452 	for (n = G_MIRROR_BALANCE_MIN; n <= G_MIRROR_BALANCE_MAX; n++) {
453 		if (strcmp(name, algorithms[n]) == 0)
454 			return (n);
455 	}
456 	return (-1);
457 }
458 
459 static __inline void
460 mirror_metadata_dump(const struct g_mirror_metadata *md)
461 {
462 	static const char hex[] = "0123456789abcdef";
463 	char hash[16 * 2 + 1];
464 	u_int i;
465 
466 	printf("     magic: %s\n", md->md_magic);
467 	printf("   version: %u\n", (u_int)md->md_version);
468 	printf("      name: %s\n", md->md_name);
469 	printf("       mid: %u\n", (u_int)md->md_mid);
470 	printf("       did: %u\n", (u_int)md->md_did);
471 	printf("       all: %u\n", (u_int)md->md_all);
472 	printf("     genid: %u\n", (u_int)md->md_genid);
473 	printf("    syncid: %u\n", (u_int)md->md_syncid);
474 	printf("  priority: %u\n", (u_int)md->md_priority);
475 	printf("     slice: %u\n", (u_int)md->md_slice);
476 	printf("   balance: %s\n", balance_name((u_int)md->md_balance));
477 	printf(" mediasize: %jd\n", (intmax_t)md->md_mediasize);
478 	printf("sectorsize: %u\n", (u_int)md->md_sectorsize);
479 	printf("syncoffset: %jd\n", (intmax_t)md->md_sync_offset);
480 	printf("    mflags:");
481 	if (md->md_mflags == 0)
482 		printf(" NONE");
483 	else {
484 		if ((md->md_mflags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
485 			printf(" NOFAILSYNC");
486 		if ((md->md_mflags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0)
487 			printf(" NOAUTOSYNC");
488 	}
489 	printf("\n");
490 	printf("    dflags:");
491 	if (md->md_dflags == 0)
492 		printf(" NONE");
493 	else {
494 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_DIRTY) != 0)
495 			printf(" DIRTY");
496 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0)
497 			printf(" SYNCHRONIZING");
498 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0)
499 			printf(" FORCE_SYNC");
500 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0)
501 			printf(" INACTIVE");
502 	}
503 	printf("\n");
504 	printf("hcprovider: %s\n", md->md_provider);
505 	printf("  provsize: %ju\n", (uintmax_t)md->md_provsize);
506 	bzero(hash, sizeof(hash));
507 	for (i = 0; i < 16; i++) {
508 		hash[i * 2] = hex[md->md_hash[i] >> 4];
509 		hash[i * 2 + 1] = hex[md->md_hash[i] & 0x0f];
510 	}
511 	printf("  MD5 hash: %s\n", hash);
512 }
513 #endif	/* !_G_MIRROR_H_ */
514