g_part_ebr.c revision 231754
1/*-
2 * Copyright (c) 2007-2009 Marcel Moolenaar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "opt_geom.h"
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/sys/geom/part/g_part_ebr.c 231754 2012-02-15 10:33:29Z ae $");
31
32#include <sys/param.h>
33#include <sys/bio.h>
34#include <sys/diskmbr.h>
35#include <sys/endian.h>
36#include <sys/kernel.h>
37#include <sys/kobj.h>
38#include <sys/limits.h>
39#include <sys/lock.h>
40#include <sys/malloc.h>
41#include <sys/mutex.h>
42#include <sys/queue.h>
43#include <sys/sbuf.h>
44#include <sys/systm.h>
45#include <sys/sysctl.h>
46#include <geom/geom.h>
47#include <geom/part/g_part.h>
48
49#include "g_part_if.h"
50
51FEATURE(geom_part_ebr,
52    "GEOM partitioning class for extended boot records support");
53#if defined(GEOM_PART_EBR_COMPAT)
54FEATURE(geom_part_ebr_compat,
55    "GEOM EBR partitioning class: backward-compatible partition names");
56#endif
57
58#define	EBRSIZE		512
59
60struct g_part_ebr_table {
61	struct g_part_table	base;
62#ifndef GEOM_PART_EBR_COMPAT
63	u_char		ebr[EBRSIZE];
64#endif
65};
66
67struct g_part_ebr_entry {
68	struct g_part_entry	base;
69	struct dos_partition	ent;
70};
71
72static int g_part_ebr_add(struct g_part_table *, struct g_part_entry *,
73    struct g_part_parms *);
74static int g_part_ebr_create(struct g_part_table *, struct g_part_parms *);
75static int g_part_ebr_destroy(struct g_part_table *, struct g_part_parms *);
76static void g_part_ebr_dumpconf(struct g_part_table *, struct g_part_entry *,
77    struct sbuf *, const char *);
78static int g_part_ebr_dumpto(struct g_part_table *, struct g_part_entry *);
79#if defined(GEOM_PART_EBR_COMPAT)
80static void g_part_ebr_fullname(struct g_part_table *, struct g_part_entry *,
81    struct sbuf *, const char *);
82#endif
83static int g_part_ebr_modify(struct g_part_table *, struct g_part_entry *,
84    struct g_part_parms *);
85static const char *g_part_ebr_name(struct g_part_table *, struct g_part_entry *,
86    char *, size_t);
87static int g_part_ebr_precheck(struct g_part_table *, enum g_part_ctl,
88    struct g_part_parms *);
89static int g_part_ebr_probe(struct g_part_table *, struct g_consumer *);
90static int g_part_ebr_read(struct g_part_table *, struct g_consumer *);
91static int g_part_ebr_setunset(struct g_part_table *, struct g_part_entry *,
92    const char *, unsigned int);
93static const char *g_part_ebr_type(struct g_part_table *, struct g_part_entry *,
94    char *, size_t);
95static int g_part_ebr_write(struct g_part_table *, struct g_consumer *);
96
97static kobj_method_t g_part_ebr_methods[] = {
98	KOBJMETHOD(g_part_add,		g_part_ebr_add),
99	KOBJMETHOD(g_part_create,	g_part_ebr_create),
100	KOBJMETHOD(g_part_destroy,	g_part_ebr_destroy),
101	KOBJMETHOD(g_part_dumpconf,	g_part_ebr_dumpconf),
102	KOBJMETHOD(g_part_dumpto,	g_part_ebr_dumpto),
103#if defined(GEOM_PART_EBR_COMPAT)
104	KOBJMETHOD(g_part_fullname,	g_part_ebr_fullname),
105#endif
106	KOBJMETHOD(g_part_modify,	g_part_ebr_modify),
107	KOBJMETHOD(g_part_name,		g_part_ebr_name),
108	KOBJMETHOD(g_part_precheck,	g_part_ebr_precheck),
109	KOBJMETHOD(g_part_probe,	g_part_ebr_probe),
110	KOBJMETHOD(g_part_read,		g_part_ebr_read),
111	KOBJMETHOD(g_part_setunset,	g_part_ebr_setunset),
112	KOBJMETHOD(g_part_type,		g_part_ebr_type),
113	KOBJMETHOD(g_part_write,	g_part_ebr_write),
114	{ 0, 0 }
115};
116
117static struct g_part_scheme g_part_ebr_scheme = {
118	"EBR",
119	g_part_ebr_methods,
120	sizeof(struct g_part_ebr_table),
121	.gps_entrysz = sizeof(struct g_part_ebr_entry),
122	.gps_minent = 1,
123	.gps_maxent = INT_MAX,
124};
125G_PART_SCHEME_DECLARE(g_part_ebr);
126
127static struct g_part_ebr_alias {
128	u_char		typ;
129	int		alias;
130} ebr_alias_match[] = {
131	{ DOSPTYP_386BSD,	G_PART_ALIAS_FREEBSD },
132	{ DOSPTYP_NTFS,		G_PART_ALIAS_MS_NTFS },
133	{ DOSPTYP_FAT32,	G_PART_ALIAS_MS_FAT32 },
134	{ DOSPTYP_LINSWP,	G_PART_ALIAS_LINUX_SWAP },
135	{ DOSPTYP_LINUX,	G_PART_ALIAS_LINUX_DATA },
136	{ DOSPTYP_LINLVM,	G_PART_ALIAS_LINUX_LVM },
137	{ DOSPTYP_LINRAID,	G_PART_ALIAS_LINUX_RAID },
138};
139
140static void ebr_set_chs(struct g_part_table *, uint32_t, u_char *, u_char *,
141    u_char *);
142
143static void
144ebr_entry_decode(const char *p, struct dos_partition *ent)
145{
146	ent->dp_flag = p[0];
147	ent->dp_shd = p[1];
148	ent->dp_ssect = p[2];
149	ent->dp_scyl = p[3];
150	ent->dp_typ = p[4];
151	ent->dp_ehd = p[5];
152	ent->dp_esect = p[6];
153	ent->dp_ecyl = p[7];
154	ent->dp_start = le32dec(p + 8);
155	ent->dp_size = le32dec(p + 12);
156}
157
158static void
159ebr_entry_link(struct g_part_table *table, uint32_t start, uint32_t end,
160   u_char *buf)
161{
162
163	buf[0] = 0 /* dp_flag */;
164	ebr_set_chs(table, start, &buf[3] /* dp_scyl */, &buf[1] /* dp_shd */,
165	    &buf[2] /* dp_ssect */);
166	buf[4] = 5 /* dp_typ */;
167	ebr_set_chs(table, end, &buf[7] /* dp_ecyl */, &buf[5] /* dp_ehd */,
168	    &buf[6] /* dp_esect */);
169	le32enc(buf + 8, start);
170	le32enc(buf + 12, end - start + 1);
171}
172
173static int
174ebr_parse_type(const char *type, u_char *dp_typ)
175{
176	const char *alias;
177	char *endp;
178	long lt;
179	int i;
180
181	if (type[0] == '!') {
182		lt = strtol(type + 1, &endp, 0);
183		if (type[1] == '\0' || *endp != '\0' || lt <= 0 || lt >= 256)
184			return (EINVAL);
185		*dp_typ = (u_char)lt;
186		return (0);
187	}
188	for (i = 0;
189	    i < sizeof(ebr_alias_match) / sizeof(ebr_alias_match[0]); i++) {
190		alias = g_part_alias_name(ebr_alias_match[i].alias);
191		if (strcasecmp(type, alias) == 0) {
192			*dp_typ = ebr_alias_match[i].typ;
193			return (0);
194		}
195	}
196	return (EINVAL);
197}
198
199
200static void
201ebr_set_chs(struct g_part_table *table, uint32_t lba, u_char *cylp, u_char *hdp,
202    u_char *secp)
203{
204	uint32_t cyl, hd, sec;
205
206	sec = lba % table->gpt_sectors + 1;
207	lba /= table->gpt_sectors;
208	hd = lba % table->gpt_heads;
209	lba /= table->gpt_heads;
210	cyl = lba;
211	if (cyl > 1023)
212		sec = hd = cyl = ~0;
213
214	*cylp = cyl & 0xff;
215	*hdp = hd & 0xff;
216	*secp = (sec & 0x3f) | ((cyl >> 2) & 0xc0);
217}
218
219static int
220g_part_ebr_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
221    struct g_part_parms *gpp)
222{
223	struct g_geom *gp;
224	struct g_provider *pp;
225	struct g_part_ebr_entry *entry;
226	uint32_t start, size, sectors;
227
228	if (gpp->gpp_parms & G_PART_PARM_LABEL)
229		return (EINVAL);
230
231	gp = basetable->gpt_gp;
232	pp = LIST_FIRST(&gp->consumer)->provider;
233	sectors = basetable->gpt_sectors;
234
235	entry = (struct g_part_ebr_entry *)baseentry;
236
237	start = gpp->gpp_start;
238	size = gpp->gpp_size;
239	if (size < 2 * sectors)
240		return (EINVAL);
241	if (start % sectors) {
242		size = size - sectors + (start % sectors);
243		start = start - (start % sectors) + sectors;
244	}
245	if (size % sectors)
246		size = size - (size % sectors);
247	if (size < 2 * sectors)
248		return (EINVAL);
249
250	if (baseentry->gpe_deleted)
251		bzero(&entry->ent, sizeof(entry->ent));
252
253	KASSERT(baseentry->gpe_start <= start, ("%s", __func__));
254	KASSERT(baseentry->gpe_end >= start + size - 1, ("%s", __func__));
255	baseentry->gpe_index = (start / sectors) + 1;
256	baseentry->gpe_offset = (off_t)(start + sectors) * pp->sectorsize;
257	baseentry->gpe_start = start;
258	baseentry->gpe_end = start + size - 1;
259	entry->ent.dp_start = sectors;
260	entry->ent.dp_size = size - sectors;
261	ebr_set_chs(basetable, entry->ent.dp_start, &entry->ent.dp_scyl,
262	    &entry->ent.dp_shd, &entry->ent.dp_ssect);
263	ebr_set_chs(basetable, baseentry->gpe_end, &entry->ent.dp_ecyl,
264	    &entry->ent.dp_ehd, &entry->ent.dp_esect);
265	return (ebr_parse_type(gpp->gpp_type, &entry->ent.dp_typ));
266}
267
268static int
269g_part_ebr_create(struct g_part_table *basetable, struct g_part_parms *gpp)
270{
271	char type[64];
272	struct g_consumer *cp;
273	struct g_provider *pp;
274	uint32_t msize;
275	int error;
276
277	pp = gpp->gpp_provider;
278
279	if (pp->sectorsize < EBRSIZE)
280		return (ENOSPC);
281	if (pp->sectorsize > 4096)
282		return (ENXIO);
283
284	/* Check that we have a parent and that it's a MBR. */
285	if (basetable->gpt_depth == 0)
286		return (ENXIO);
287	cp = LIST_FIRST(&pp->consumers);
288	error = g_getattr("PART::scheme", cp, &type);
289	if (error != 0)
290		return (error);
291	if (strcmp(type, "MBR") != 0)
292		return (ENXIO);
293	error = g_getattr("PART::type", cp, &type);
294	if (error != 0)
295		return (error);
296	if (strcmp(type, "ebr") != 0)
297		return (ENXIO);
298
299	msize = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX);
300	basetable->gpt_first = 0;
301	basetable->gpt_last = msize - 1;
302	basetable->gpt_entries = msize / basetable->gpt_sectors;
303	return (0);
304}
305
306static int
307g_part_ebr_destroy(struct g_part_table *basetable, struct g_part_parms *gpp)
308{
309
310	/* Wipe the first sector to clear the partitioning. */
311	basetable->gpt_smhead |= 1;
312	return (0);
313}
314
315static void
316g_part_ebr_dumpconf(struct g_part_table *table, struct g_part_entry *baseentry,
317    struct sbuf *sb, const char *indent)
318{
319	struct g_part_ebr_entry *entry;
320
321	entry = (struct g_part_ebr_entry *)baseentry;
322	if (indent == NULL) {
323		/* conftxt: libdisk compatibility */
324		sbuf_printf(sb, " xs MBREXT xt %u", entry->ent.dp_typ);
325	} else if (entry != NULL) {
326		/* confxml: partition entry information */
327		sbuf_printf(sb, "%s<rawtype>%u</rawtype>\n", indent,
328		    entry->ent.dp_typ);
329		if (entry->ent.dp_flag & 0x80)
330			sbuf_printf(sb, "%s<attrib>active</attrib>\n", indent);
331	} else {
332		/* confxml: scheme information */
333	}
334}
335
336static int
337g_part_ebr_dumpto(struct g_part_table *table, struct g_part_entry *baseentry)
338{
339	struct g_part_ebr_entry *entry;
340
341	/* Allow dumping to a FreeBSD partition or Linux swap partition only. */
342	entry = (struct g_part_ebr_entry *)baseentry;
343	return ((entry->ent.dp_typ == DOSPTYP_386BSD ||
344	    entry->ent.dp_typ == DOSPTYP_LINSWP) ? 1 : 0);
345}
346
347#if defined(GEOM_PART_EBR_COMPAT)
348static void
349g_part_ebr_fullname(struct g_part_table *table, struct g_part_entry *entry,
350    struct sbuf *sb, const char *pfx)
351{
352	struct g_part_entry *iter;
353	u_int idx;
354
355	idx = 5;
356	LIST_FOREACH(iter, &table->gpt_entry, gpe_entry) {
357		if (iter == entry)
358			break;
359		idx++;
360	}
361	sbuf_printf(sb, "%.*s%u", (int)strlen(pfx) - 1, pfx, idx);
362}
363#endif
364
365static int
366g_part_ebr_modify(struct g_part_table *basetable,
367    struct g_part_entry *baseentry, struct g_part_parms *gpp)
368{
369	struct g_part_ebr_entry *entry;
370
371	if (gpp->gpp_parms & G_PART_PARM_LABEL)
372		return (EINVAL);
373
374	entry = (struct g_part_ebr_entry *)baseentry;
375	if (gpp->gpp_parms & G_PART_PARM_TYPE)
376		return (ebr_parse_type(gpp->gpp_type, &entry->ent.dp_typ));
377	return (0);
378}
379
380static const char *
381g_part_ebr_name(struct g_part_table *table, struct g_part_entry *entry,
382    char *buf, size_t bufsz)
383{
384
385	snprintf(buf, bufsz, "+%08u", entry->gpe_index);
386	return (buf);
387}
388
389static int
390g_part_ebr_precheck(struct g_part_table *table, enum g_part_ctl req,
391    struct g_part_parms *gpp)
392{
393#if defined(GEOM_PART_EBR_COMPAT)
394	if (req == G_PART_CTL_DESTROY)
395		return (0);
396	return (ECANCELED);
397#else
398	/*
399	 * The index is a function of the start of the partition.
400	 * This is not something the user can override, nor is it
401	 * something the common code will do right. We can set the
402	 * index now so that we get what we need.
403	 */
404	if (req == G_PART_CTL_ADD)
405		gpp->gpp_index = (gpp->gpp_start / table->gpt_sectors) + 1;
406	return (0);
407#endif
408}
409
410static int
411g_part_ebr_probe(struct g_part_table *table, struct g_consumer *cp)
412{
413	char type[64];
414	struct g_provider *pp;
415	u_char *buf, *p;
416	int error, index, res;
417	uint16_t magic;
418
419	pp = cp->provider;
420
421	/* Sanity-check the provider. */
422	if (pp->sectorsize < EBRSIZE || pp->mediasize < pp->sectorsize)
423		return (ENOSPC);
424	if (pp->sectorsize > 4096)
425		return (ENXIO);
426
427	/* Check that we have a parent and that it's a MBR. */
428	if (table->gpt_depth == 0)
429		return (ENXIO);
430	error = g_getattr("PART::scheme", cp, &type);
431	if (error != 0)
432		return (error);
433	if (strcmp(type, "MBR") != 0)
434		return (ENXIO);
435	/* Check that partition has type DOSPTYP_EBR. */
436	error = g_getattr("PART::type", cp, &type);
437	if (error != 0)
438		return (error);
439	if (strcmp(type, "ebr") != 0)
440		return (ENXIO);
441
442	/* Check that there's a EBR. */
443	buf = g_read_data(cp, 0L, pp->sectorsize, &error);
444	if (buf == NULL)
445		return (error);
446
447	/* We goto out on mismatch. */
448	res = ENXIO;
449
450	magic = le16dec(buf + DOSMAGICOFFSET);
451	if (magic != DOSMAGIC)
452		goto out;
453
454	for (index = 0; index < 2; index++) {
455		p = buf + DOSPARTOFF + index * DOSPARTSIZE;
456		if (p[0] != 0 && p[0] != 0x80)
457			goto out;
458	}
459	res = G_PART_PROBE_PRI_NORM;
460
461 out:
462	g_free(buf);
463	return (res);
464}
465
466static int
467g_part_ebr_read(struct g_part_table *basetable, struct g_consumer *cp)
468{
469	struct dos_partition ent[2];
470	struct g_provider *pp;
471	struct g_part_entry *baseentry;
472	struct g_part_ebr_table *table;
473	struct g_part_ebr_entry *entry;
474	u_char *buf;
475	off_t ofs, msize;
476	u_int lba;
477	int error, index;
478
479	pp = cp->provider;
480	table = (struct g_part_ebr_table *)basetable;
481	msize = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX);
482
483	lba = 0;
484	while (1) {
485		ofs = (off_t)lba * pp->sectorsize;
486		buf = g_read_data(cp, ofs, pp->sectorsize, &error);
487		if (buf == NULL)
488			return (error);
489
490		ebr_entry_decode(buf + DOSPARTOFF + 0 * DOSPARTSIZE, ent + 0);
491		ebr_entry_decode(buf + DOSPARTOFF + 1 * DOSPARTSIZE, ent + 1);
492
493		/* The 3rd & 4th entries should be zeroes. */
494		if (le64dec(buf + DOSPARTOFF + 2 * DOSPARTSIZE) +
495		    le64dec(buf + DOSPARTOFF + 3 * DOSPARTSIZE) != 0) {
496			basetable->gpt_corrupt = 1;
497			printf("GEOM: %s: invalid entries in the EBR ignored.\n",
498			    pp->name);
499		}
500#ifndef GEOM_PART_EBR_COMPAT
501		/* Save the first EBR, it can contain a boot code */
502		if (lba == 0)
503			bcopy(buf, table->ebr, sizeof(table->ebr));
504#endif
505		g_free(buf);
506
507		if (ent[0].dp_typ == 0)
508			break;
509
510		if (ent[0].dp_typ == 5 && ent[1].dp_typ == 0) {
511			lba = ent[0].dp_start;
512			continue;
513		}
514
515		index = (lba / basetable->gpt_sectors) + 1;
516		baseentry = (struct g_part_entry *)g_part_new_entry(basetable,
517		    index, lba, lba + ent[0].dp_start + ent[0].dp_size - 1);
518		baseentry->gpe_offset = (off_t)(lba + ent[0].dp_start) *
519		    pp->sectorsize;
520		entry = (struct g_part_ebr_entry *)baseentry;
521		entry->ent = ent[0];
522
523		if (ent[1].dp_typ == 0)
524			break;
525
526		lba = ent[1].dp_start;
527	}
528
529	basetable->gpt_entries = msize / basetable->gpt_sectors;
530	basetable->gpt_first = 0;
531	basetable->gpt_last = msize - 1;
532	return (0);
533}
534
535static int
536g_part_ebr_setunset(struct g_part_table *table, struct g_part_entry *baseentry,
537    const char *attrib, unsigned int set)
538{
539	struct g_part_entry *iter;
540	struct g_part_ebr_entry *entry;
541	int changed;
542
543	if (strcasecmp(attrib, "active") != 0)
544		return (EINVAL);
545
546	/* Only one entry can have the active attribute. */
547	LIST_FOREACH(iter, &table->gpt_entry, gpe_entry) {
548		if (iter->gpe_deleted)
549			continue;
550		changed = 0;
551		entry = (struct g_part_ebr_entry *)iter;
552		if (iter == baseentry) {
553			if (set && (entry->ent.dp_flag & 0x80) == 0) {
554				entry->ent.dp_flag |= 0x80;
555				changed = 1;
556			} else if (!set && (entry->ent.dp_flag & 0x80)) {
557				entry->ent.dp_flag &= ~0x80;
558				changed = 1;
559			}
560		} else {
561			if (set && (entry->ent.dp_flag & 0x80)) {
562				entry->ent.dp_flag &= ~0x80;
563				changed = 1;
564			}
565		}
566		if (changed && !iter->gpe_created)
567			iter->gpe_modified = 1;
568	}
569	return (0);
570}
571
572static const char *
573g_part_ebr_type(struct g_part_table *basetable, struct g_part_entry *baseentry,
574    char *buf, size_t bufsz)
575{
576	struct g_part_ebr_entry *entry;
577	int i;
578
579	entry = (struct g_part_ebr_entry *)baseentry;
580	for (i = 0;
581	    i < sizeof(ebr_alias_match) / sizeof(ebr_alias_match[0]); i++) {
582		if (ebr_alias_match[i].typ == entry->ent.dp_typ)
583			return (g_part_alias_name(ebr_alias_match[i].alias));
584	}
585	snprintf(buf, bufsz, "!%d", entry->ent.dp_typ);
586	return (buf);
587}
588
589static int
590g_part_ebr_write(struct g_part_table *basetable, struct g_consumer *cp)
591{
592#ifndef GEOM_PART_EBR_COMPAT
593	struct g_part_ebr_table *table;
594#endif
595	struct g_provider *pp;
596	struct g_part_entry *baseentry, *next;
597	struct g_part_ebr_entry *entry;
598	u_char *buf;
599	u_char *p;
600	int error;
601
602	pp = cp->provider;
603	buf = g_malloc(pp->sectorsize, M_WAITOK | M_ZERO);
604#ifndef GEOM_PART_EBR_COMPAT
605	table = (struct g_part_ebr_table *)basetable;
606	bcopy(table->ebr, buf, DOSPARTOFF);
607#endif
608	le16enc(buf + DOSMAGICOFFSET, DOSMAGIC);
609
610	baseentry = LIST_FIRST(&basetable->gpt_entry);
611	while (baseentry != NULL && baseentry->gpe_deleted)
612		baseentry = LIST_NEXT(baseentry, gpe_entry);
613
614	/* Wipe-out the first EBR when there are no slices. */
615	if (baseentry == NULL) {
616		error = g_write_data(cp, 0, buf, pp->sectorsize);
617		goto out;
618	}
619
620	/*
621	 * If the first partition is not in LBA 0, we need to
622	 * put a "link" EBR in LBA 0.
623	 */
624	if (baseentry->gpe_start != 0) {
625		ebr_entry_link(basetable, (uint32_t)baseentry->gpe_start,
626		    (uint32_t)baseentry->gpe_end, buf + DOSPARTOFF);
627		error = g_write_data(cp, 0, buf, pp->sectorsize);
628		if (error)
629			goto out;
630	}
631
632	do {
633		entry = (struct g_part_ebr_entry *)baseentry;
634
635		p = buf + DOSPARTOFF;
636		p[0] = entry->ent.dp_flag;
637		p[1] = entry->ent.dp_shd;
638		p[2] = entry->ent.dp_ssect;
639		p[3] = entry->ent.dp_scyl;
640		p[4] = entry->ent.dp_typ;
641		p[5] = entry->ent.dp_ehd;
642		p[6] = entry->ent.dp_esect;
643		p[7] = entry->ent.dp_ecyl;
644		le32enc(p + 8, entry->ent.dp_start);
645		le32enc(p + 12, entry->ent.dp_size);
646
647		next = LIST_NEXT(baseentry, gpe_entry);
648		while (next != NULL && next->gpe_deleted)
649			next = LIST_NEXT(next, gpe_entry);
650
651		p += DOSPARTSIZE;
652		if (next != NULL)
653			ebr_entry_link(basetable, (uint32_t)next->gpe_start,
654			    (uint32_t)next->gpe_end, p);
655		else
656			bzero(p, DOSPARTSIZE);
657
658		error = g_write_data(cp, baseentry->gpe_start * pp->sectorsize,
659		    buf, pp->sectorsize);
660#ifndef GEOM_PART_EBR_COMPAT
661		if (baseentry->gpe_start == 0)
662			bzero(buf, DOSPARTOFF);
663#endif
664		baseentry = next;
665	} while (!error && baseentry != NULL);
666
667 out:
668	g_free(buf);
669	return (error);
670}
671