xref: /freebsd/sys/dev/md/md.c (revision c6a33c8e88c5684876e670c8189d03ad25108d8a)
1 /*-
2  * ----------------------------------------------------------------------------
3  * "THE BEER-WARE LICENSE" (Revision 42):
4  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
5  * can do whatever you want with this stuff. If we meet some day, and you think
6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
7  * ----------------------------------------------------------------------------
8  *
9  * $FreeBSD$
10  *
11  */
12 
13 /*-
14  * The following functions are based in the vn(4) driver: mdstart_swap(),
15  * mdstart_vnode(), mdcreate_swap(), mdcreate_vnode() and mddestroy(),
16  * and as such under the following copyright:
17  *
18  * Copyright (c) 1988 University of Utah.
19  * Copyright (c) 1990, 1993
20  *	The Regents of the University of California.  All rights reserved.
21  * Copyright (c) 2013 The FreeBSD Foundation
22  * All rights reserved.
23  *
24  * This code is derived from software contributed to Berkeley by
25  * the Systems Programming Group of the University of Utah Computer
26  * Science Department.
27  *
28  * Portions of this software were developed by Konstantin Belousov
29  * under sponsorship from the FreeBSD Foundation.
30  *
31  * Redistribution and use in source and binary forms, with or without
32  * modification, are permitted provided that the following conditions
33  * are met:
34  * 1. Redistributions of source code must retain the above copyright
35  *    notice, this list of conditions and the following disclaimer.
36  * 2. Redistributions in binary form must reproduce the above copyright
37  *    notice, this list of conditions and the following disclaimer in the
38  *    documentation and/or other materials provided with the distribution.
39  * 4. Neither the name of the University nor the names of its contributors
40  *    may be used to endorse or promote products derived from this software
41  *    without specific prior written permission.
42  *
43  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53  * SUCH DAMAGE.
54  *
55  * from: Utah Hdr: vn.c 1.13 94/04/02
56  *
57  *	from: @(#)vn.c	8.6 (Berkeley) 4/1/94
58  * From: src/sys/dev/vn/vn.c,v 1.122 2000/12/16 16:06:03
59  */
60 
61 #include "opt_geom.h"
62 #include "opt_md.h"
63 
64 #include <sys/param.h>
65 #include <sys/systm.h>
66 #include <sys/bio.h>
67 #include <sys/buf.h>
68 #include <sys/conf.h>
69 #include <sys/devicestat.h>
70 #include <sys/fcntl.h>
71 #include <sys/kernel.h>
72 #include <sys/kthread.h>
73 #include <sys/limits.h>
74 #include <sys/linker.h>
75 #include <sys/lock.h>
76 #include <sys/malloc.h>
77 #include <sys/mdioctl.h>
78 #include <sys/mount.h>
79 #include <sys/mutex.h>
80 #include <sys/sx.h>
81 #include <sys/namei.h>
82 #include <sys/proc.h>
83 #include <sys/queue.h>
84 #include <sys/rwlock.h>
85 #include <sys/sbuf.h>
86 #include <sys/sched.h>
87 #include <sys/sf_buf.h>
88 #include <sys/sysctl.h>
89 #include <sys/vnode.h>
90 
91 #include <geom/geom.h>
92 #include <geom/geom_int.h>
93 
94 #include <vm/vm.h>
95 #include <vm/vm_param.h>
96 #include <vm/vm_object.h>
97 #include <vm/vm_page.h>
98 #include <vm/vm_pager.h>
99 #include <vm/swap_pager.h>
100 #include <vm/uma.h>
101 
102 #include <machine/bus.h>
103 
104 #define MD_MODVER 1
105 
106 #define MD_SHUTDOWN	0x10000		/* Tell worker thread to terminate. */
107 #define	MD_EXITING	0x20000		/* Worker thread is exiting. */
108 
109 #ifndef MD_NSECT
110 #define MD_NSECT (10000 * 2)
111 #endif
112 
113 static MALLOC_DEFINE(M_MD, "md_disk", "Memory Disk");
114 static MALLOC_DEFINE(M_MDSECT, "md_sectors", "Memory Disk Sectors");
115 
116 static int md_debug;
117 SYSCTL_INT(_debug, OID_AUTO, mddebug, CTLFLAG_RW, &md_debug, 0,
118     "Enable md(4) debug messages");
119 static int md_malloc_wait;
120 SYSCTL_INT(_vm, OID_AUTO, md_malloc_wait, CTLFLAG_RW, &md_malloc_wait, 0,
121     "Allow malloc to wait for memory allocations");
122 
123 #if defined(MD_ROOT) && !defined(MD_ROOT_FSTYPE)
124 #define	MD_ROOT_FSTYPE	"ufs"
125 #endif
126 
127 #if defined(MD_ROOT)
128 /*
129  * Preloaded image gets put here.
130  */
131 #if defined(MD_ROOT_SIZE)
132 /*
133  * Applications that patch the object with the image can determine
134  * the size looking at the start and end markers (strings),
135  * so we want them contiguous.
136  */
137 static struct {
138 	u_char start[MD_ROOT_SIZE*1024];
139 	u_char end[128];
140 } mfs_root = {
141 	.start = "MFS Filesystem goes here",
142 	.end = "MFS Filesystem had better STOP here",
143 };
144 const int mfs_root_size = sizeof(mfs_root.start);
145 #else
146 extern volatile u_char __weak_symbol mfs_root;
147 extern volatile u_char __weak_symbol mfs_root_end;
148 __GLOBL(mfs_root);
149 __GLOBL(mfs_root_end);
150 #define mfs_root_size ((uintptr_t)(&mfs_root_end - &mfs_root))
151 #endif
152 #endif
153 
154 static g_init_t g_md_init;
155 static g_fini_t g_md_fini;
156 static g_start_t g_md_start;
157 static g_access_t g_md_access;
158 static void g_md_dumpconf(struct sbuf *sb, const char *indent,
159     struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp);
160 
161 static struct cdev *status_dev = 0;
162 static struct sx md_sx;
163 static struct unrhdr *md_uh;
164 
165 static d_ioctl_t mdctlioctl;
166 
167 static struct cdevsw mdctl_cdevsw = {
168 	.d_version =	D_VERSION,
169 	.d_ioctl =	mdctlioctl,
170 	.d_name =	MD_NAME,
171 };
172 
173 struct g_class g_md_class = {
174 	.name = "MD",
175 	.version = G_VERSION,
176 	.init = g_md_init,
177 	.fini = g_md_fini,
178 	.start = g_md_start,
179 	.access = g_md_access,
180 	.dumpconf = g_md_dumpconf,
181 };
182 
183 DECLARE_GEOM_CLASS(g_md_class, g_md);
184 
185 
186 static LIST_HEAD(, md_s) md_softc_list = LIST_HEAD_INITIALIZER(md_softc_list);
187 
188 #define NINDIR	(PAGE_SIZE / sizeof(uintptr_t))
189 #define NMASK	(NINDIR-1)
190 static int nshift;
191 
192 static int md_vnode_pbuf_freecnt;
193 
194 struct indir {
195 	uintptr_t	*array;
196 	u_int		total;
197 	u_int		used;
198 	u_int		shift;
199 };
200 
201 struct md_s {
202 	int unit;
203 	LIST_ENTRY(md_s) list;
204 	struct bio_queue_head bio_queue;
205 	struct mtx queue_mtx;
206 	struct mtx stat_mtx;
207 	struct cdev *dev;
208 	enum md_types type;
209 	off_t mediasize;
210 	unsigned sectorsize;
211 	unsigned opencount;
212 	unsigned fwheads;
213 	unsigned fwsectors;
214 	unsigned flags;
215 	char name[20];
216 	struct proc *procp;
217 	struct g_geom *gp;
218 	struct g_provider *pp;
219 	int (*start)(struct md_s *sc, struct bio *bp);
220 	struct devstat *devstat;
221 
222 	/* MD_MALLOC related fields */
223 	struct indir *indir;
224 	uma_zone_t uma;
225 
226 	/* MD_PRELOAD related fields */
227 	u_char *pl_ptr;
228 	size_t pl_len;
229 
230 	/* MD_VNODE related fields */
231 	struct vnode *vnode;
232 	char file[PATH_MAX];
233 	struct ucred *cred;
234 
235 	/* MD_SWAP related fields */
236 	vm_object_t object;
237 };
238 
239 static struct indir *
240 new_indir(u_int shift)
241 {
242 	struct indir *ip;
243 
244 	ip = malloc(sizeof *ip, M_MD, (md_malloc_wait ? M_WAITOK : M_NOWAIT)
245 	    | M_ZERO);
246 	if (ip == NULL)
247 		return (NULL);
248 	ip->array = malloc(sizeof(uintptr_t) * NINDIR,
249 	    M_MDSECT, (md_malloc_wait ? M_WAITOK : M_NOWAIT) | M_ZERO);
250 	if (ip->array == NULL) {
251 		free(ip, M_MD);
252 		return (NULL);
253 	}
254 	ip->total = NINDIR;
255 	ip->shift = shift;
256 	return (ip);
257 }
258 
259 static void
260 del_indir(struct indir *ip)
261 {
262 
263 	free(ip->array, M_MDSECT);
264 	free(ip, M_MD);
265 }
266 
267 static void
268 destroy_indir(struct md_s *sc, struct indir *ip)
269 {
270 	int i;
271 
272 	for (i = 0; i < NINDIR; i++) {
273 		if (!ip->array[i])
274 			continue;
275 		if (ip->shift)
276 			destroy_indir(sc, (struct indir*)(ip->array[i]));
277 		else if (ip->array[i] > 255)
278 			uma_zfree(sc->uma, (void *)(ip->array[i]));
279 	}
280 	del_indir(ip);
281 }
282 
283 /*
284  * This function does the math and allocates the top level "indir" structure
285  * for a device of "size" sectors.
286  */
287 
288 static struct indir *
289 dimension(off_t size)
290 {
291 	off_t rcnt;
292 	struct indir *ip;
293 	int layer;
294 
295 	rcnt = size;
296 	layer = 0;
297 	while (rcnt > NINDIR) {
298 		rcnt /= NINDIR;
299 		layer++;
300 	}
301 
302 	/*
303 	 * XXX: the top layer is probably not fully populated, so we allocate
304 	 * too much space for ip->array in here.
305 	 */
306 	ip = malloc(sizeof *ip, M_MD, M_WAITOK | M_ZERO);
307 	ip->array = malloc(sizeof(uintptr_t) * NINDIR,
308 	    M_MDSECT, M_WAITOK | M_ZERO);
309 	ip->total = NINDIR;
310 	ip->shift = layer * nshift;
311 	return (ip);
312 }
313 
314 /*
315  * Read a given sector
316  */
317 
318 static uintptr_t
319 s_read(struct indir *ip, off_t offset)
320 {
321 	struct indir *cip;
322 	int idx;
323 	uintptr_t up;
324 
325 	if (md_debug > 1)
326 		printf("s_read(%jd)\n", (intmax_t)offset);
327 	up = 0;
328 	for (cip = ip; cip != NULL;) {
329 		if (cip->shift) {
330 			idx = (offset >> cip->shift) & NMASK;
331 			up = cip->array[idx];
332 			cip = (struct indir *)up;
333 			continue;
334 		}
335 		idx = offset & NMASK;
336 		return (cip->array[idx]);
337 	}
338 	return (0);
339 }
340 
341 /*
342  * Write a given sector, prune the tree if the value is 0
343  */
344 
345 static int
346 s_write(struct indir *ip, off_t offset, uintptr_t ptr)
347 {
348 	struct indir *cip, *lip[10];
349 	int idx, li;
350 	uintptr_t up;
351 
352 	if (md_debug > 1)
353 		printf("s_write(%jd, %p)\n", (intmax_t)offset, (void *)ptr);
354 	up = 0;
355 	li = 0;
356 	cip = ip;
357 	for (;;) {
358 		lip[li++] = cip;
359 		if (cip->shift) {
360 			idx = (offset >> cip->shift) & NMASK;
361 			up = cip->array[idx];
362 			if (up != 0) {
363 				cip = (struct indir *)up;
364 				continue;
365 			}
366 			/* Allocate branch */
367 			cip->array[idx] =
368 			    (uintptr_t)new_indir(cip->shift - nshift);
369 			if (cip->array[idx] == 0)
370 				return (ENOSPC);
371 			cip->used++;
372 			up = cip->array[idx];
373 			cip = (struct indir *)up;
374 			continue;
375 		}
376 		/* leafnode */
377 		idx = offset & NMASK;
378 		up = cip->array[idx];
379 		if (up != 0)
380 			cip->used--;
381 		cip->array[idx] = ptr;
382 		if (ptr != 0)
383 			cip->used++;
384 		break;
385 	}
386 	if (cip->used != 0 || li == 1)
387 		return (0);
388 	li--;
389 	while (cip->used == 0 && cip != ip) {
390 		li--;
391 		idx = (offset >> lip[li]->shift) & NMASK;
392 		up = lip[li]->array[idx];
393 		KASSERT(up == (uintptr_t)cip, ("md screwed up"));
394 		del_indir(cip);
395 		lip[li]->array[idx] = 0;
396 		lip[li]->used--;
397 		cip = lip[li];
398 	}
399 	return (0);
400 }
401 
402 
403 static int
404 g_md_access(struct g_provider *pp, int r, int w, int e)
405 {
406 	struct md_s *sc;
407 
408 	sc = pp->geom->softc;
409 	if (sc == NULL) {
410 		if (r <= 0 && w <= 0 && e <= 0)
411 			return (0);
412 		return (ENXIO);
413 	}
414 	r += pp->acr;
415 	w += pp->acw;
416 	e += pp->ace;
417 	if ((sc->flags & MD_READONLY) != 0 && w > 0)
418 		return (EROFS);
419 	if ((pp->acr + pp->acw + pp->ace) == 0 && (r + w + e) > 0) {
420 		sc->opencount = 1;
421 	} else if ((pp->acr + pp->acw + pp->ace) > 0 && (r + w + e) == 0) {
422 		sc->opencount = 0;
423 	}
424 	return (0);
425 }
426 
427 static void
428 g_md_start(struct bio *bp)
429 {
430 	struct md_s *sc;
431 
432 	sc = bp->bio_to->geom->softc;
433 	if ((bp->bio_cmd == BIO_READ) || (bp->bio_cmd == BIO_WRITE)) {
434 		mtx_lock(&sc->stat_mtx);
435 		devstat_start_transaction_bio(sc->devstat, bp);
436 		mtx_unlock(&sc->stat_mtx);
437 	}
438 	mtx_lock(&sc->queue_mtx);
439 	bioq_disksort(&sc->bio_queue, bp);
440 	mtx_unlock(&sc->queue_mtx);
441 	wakeup(sc);
442 }
443 
444 #define	MD_MALLOC_MOVE_ZERO	1
445 #define	MD_MALLOC_MOVE_FILL	2
446 #define	MD_MALLOC_MOVE_READ	3
447 #define	MD_MALLOC_MOVE_WRITE	4
448 #define	MD_MALLOC_MOVE_CMP	5
449 
450 static int
451 md_malloc_move_ma(vm_page_t **mp, int *ma_offs, unsigned sectorsize,
452     void *ptr, u_char fill, int op)
453 {
454 	struct sf_buf *sf;
455 	vm_page_t m, *mp1;
456 	char *p, first;
457 	off_t *uc;
458 	unsigned n;
459 	int error, i, ma_offs1, sz, first_read;
460 
461 	m = NULL;
462 	error = 0;
463 	sf = NULL;
464 	/* if (op == MD_MALLOC_MOVE_CMP) { gcc */
465 		first = 0;
466 		first_read = 0;
467 		uc = ptr;
468 		mp1 = *mp;
469 		ma_offs1 = *ma_offs;
470 	/* } */
471 	sched_pin();
472 	for (n = sectorsize; n != 0; n -= sz) {
473 		sz = imin(PAGE_SIZE - *ma_offs, n);
474 		if (m != **mp) {
475 			if (sf != NULL)
476 				sf_buf_free(sf);
477 			m = **mp;
478 			sf = sf_buf_alloc(m, SFB_CPUPRIVATE |
479 			    (md_malloc_wait ? 0 : SFB_NOWAIT));
480 			if (sf == NULL) {
481 				error = ENOMEM;
482 				break;
483 			}
484 		}
485 		p = (char *)sf_buf_kva(sf) + *ma_offs;
486 		switch (op) {
487 		case MD_MALLOC_MOVE_ZERO:
488 			bzero(p, sz);
489 			break;
490 		case MD_MALLOC_MOVE_FILL:
491 			memset(p, fill, sz);
492 			break;
493 		case MD_MALLOC_MOVE_READ:
494 			bcopy(ptr, p, sz);
495 			cpu_flush_dcache(p, sz);
496 			break;
497 		case MD_MALLOC_MOVE_WRITE:
498 			bcopy(p, ptr, sz);
499 			break;
500 		case MD_MALLOC_MOVE_CMP:
501 			for (i = 0; i < sz; i++, p++) {
502 				if (!first_read) {
503 					*uc = (u_char)*p;
504 					first = *p;
505 					first_read = 1;
506 				} else if (*p != first) {
507 					error = EDOOFUS;
508 					break;
509 				}
510 			}
511 			break;
512 		default:
513 			KASSERT(0, ("md_malloc_move_ma unknown op %d\n", op));
514 			break;
515 		}
516 		if (error != 0)
517 			break;
518 		*ma_offs += sz;
519 		*ma_offs %= PAGE_SIZE;
520 		if (*ma_offs == 0)
521 			(*mp)++;
522 		ptr = (char *)ptr + sz;
523 	}
524 
525 	if (sf != NULL)
526 		sf_buf_free(sf);
527 	sched_unpin();
528 	if (op == MD_MALLOC_MOVE_CMP && error != 0) {
529 		*mp = mp1;
530 		*ma_offs = ma_offs1;
531 	}
532 	return (error);
533 }
534 
535 static int
536 md_malloc_move_vlist(bus_dma_segment_t **pvlist, int *pma_offs,
537     unsigned len, void *ptr, u_char fill, int op)
538 {
539 	bus_dma_segment_t *vlist;
540 	uint8_t *p, *end, first;
541 	off_t *uc;
542 	int ma_offs, seg_len;
543 
544 	vlist = *pvlist;
545 	ma_offs = *pma_offs;
546 	uc = ptr;
547 
548 	for (; len != 0; len -= seg_len) {
549 		seg_len = imin(vlist->ds_len - ma_offs, len);
550 		p = (uint8_t *)(uintptr_t)vlist->ds_addr + ma_offs;
551 		switch (op) {
552 		case MD_MALLOC_MOVE_ZERO:
553 			bzero(p, seg_len);
554 			break;
555 		case MD_MALLOC_MOVE_FILL:
556 			memset(p, fill, seg_len);
557 			break;
558 		case MD_MALLOC_MOVE_READ:
559 			bcopy(ptr, p, seg_len);
560 			cpu_flush_dcache(p, seg_len);
561 			break;
562 		case MD_MALLOC_MOVE_WRITE:
563 			bcopy(p, ptr, seg_len);
564 			break;
565 		case MD_MALLOC_MOVE_CMP:
566 			end = p + seg_len;
567 			first = *uc = *p;
568 			/* Confirm all following bytes match the first */
569 			while (++p < end) {
570 				if (*p != first)
571 					return (EDOOFUS);
572 			}
573 			break;
574 		default:
575 			KASSERT(0, ("md_malloc_move_vlist unknown op %d\n", op));
576 			break;
577 		}
578 
579 		ma_offs += seg_len;
580 		if (ma_offs == vlist->ds_len) {
581 			ma_offs = 0;
582 			vlist++;
583 		}
584 		ptr = (uint8_t *)ptr + seg_len;
585 	}
586 	*pvlist = vlist;
587 	*pma_offs = ma_offs;
588 
589 	return (0);
590 }
591 
592 static int
593 mdstart_malloc(struct md_s *sc, struct bio *bp)
594 {
595 	u_char *dst;
596 	vm_page_t *m;
597 	bus_dma_segment_t *vlist;
598 	int i, error, error1, ma_offs, notmapped;
599 	off_t secno, nsec, uc;
600 	uintptr_t sp, osp;
601 
602 	switch (bp->bio_cmd) {
603 	case BIO_READ:
604 	case BIO_WRITE:
605 	case BIO_DELETE:
606 		break;
607 	default:
608 		return (EOPNOTSUPP);
609 	}
610 
611 	notmapped = (bp->bio_flags & BIO_UNMAPPED) != 0;
612 	vlist = (bp->bio_flags & BIO_VLIST) != 0 ?
613 	    (bus_dma_segment_t *)bp->bio_data : NULL;
614 	if (notmapped) {
615 		m = bp->bio_ma;
616 		ma_offs = bp->bio_ma_offset;
617 		dst = NULL;
618 		KASSERT(vlist == NULL, ("vlists cannot be unmapped"));
619 	} else if (vlist != NULL) {
620 		ma_offs = bp->bio_ma_offset;
621 		dst = NULL;
622 	} else {
623 		dst = bp->bio_data;
624 	}
625 
626 	nsec = bp->bio_length / sc->sectorsize;
627 	secno = bp->bio_offset / sc->sectorsize;
628 	error = 0;
629 	while (nsec--) {
630 		osp = s_read(sc->indir, secno);
631 		if (bp->bio_cmd == BIO_DELETE) {
632 			if (osp != 0)
633 				error = s_write(sc->indir, secno, 0);
634 		} else if (bp->bio_cmd == BIO_READ) {
635 			if (osp == 0) {
636 				if (notmapped) {
637 					error = md_malloc_move_ma(&m, &ma_offs,
638 					    sc->sectorsize, NULL, 0,
639 					    MD_MALLOC_MOVE_ZERO);
640 				} else if (vlist != NULL) {
641 					error = md_malloc_move_vlist(&vlist,
642 					    &ma_offs, sc->sectorsize, NULL, 0,
643 					    MD_MALLOC_MOVE_ZERO);
644 				} else
645 					bzero(dst, sc->sectorsize);
646 			} else if (osp <= 255) {
647 				if (notmapped) {
648 					error = md_malloc_move_ma(&m, &ma_offs,
649 					    sc->sectorsize, NULL, osp,
650 					    MD_MALLOC_MOVE_FILL);
651 				} else if (vlist != NULL) {
652 					error = md_malloc_move_vlist(&vlist,
653 					    &ma_offs, sc->sectorsize, NULL, osp,
654 					    MD_MALLOC_MOVE_FILL);
655 				} else
656 					memset(dst, osp, sc->sectorsize);
657 			} else {
658 				if (notmapped) {
659 					error = md_malloc_move_ma(&m, &ma_offs,
660 					    sc->sectorsize, (void *)osp, 0,
661 					    MD_MALLOC_MOVE_READ);
662 				} else if (vlist != NULL) {
663 					error = md_malloc_move_vlist(&vlist,
664 					    &ma_offs, sc->sectorsize,
665 					    (void *)osp, 0,
666 					    MD_MALLOC_MOVE_READ);
667 				} else {
668 					bcopy((void *)osp, dst, sc->sectorsize);
669 					cpu_flush_dcache(dst, sc->sectorsize);
670 				}
671 			}
672 			osp = 0;
673 		} else if (bp->bio_cmd == BIO_WRITE) {
674 			if (sc->flags & MD_COMPRESS) {
675 				if (notmapped) {
676 					error1 = md_malloc_move_ma(&m, &ma_offs,
677 					    sc->sectorsize, &uc, 0,
678 					    MD_MALLOC_MOVE_CMP);
679 					i = error1 == 0 ? sc->sectorsize : 0;
680 				} else if (vlist != NULL) {
681 					error1 = md_malloc_move_vlist(&vlist,
682 					    &ma_offs, sc->sectorsize, &uc, 0,
683 					    MD_MALLOC_MOVE_CMP);
684 					i = error1 == 0 ? sc->sectorsize : 0;
685 				} else {
686 					uc = dst[0];
687 					for (i = 1; i < sc->sectorsize; i++) {
688 						if (dst[i] != uc)
689 							break;
690 					}
691 				}
692 			} else {
693 				i = 0;
694 				uc = 0;
695 			}
696 			if (i == sc->sectorsize) {
697 				if (osp != uc)
698 					error = s_write(sc->indir, secno, uc);
699 			} else {
700 				if (osp <= 255) {
701 					sp = (uintptr_t)uma_zalloc(sc->uma,
702 					    md_malloc_wait ? M_WAITOK :
703 					    M_NOWAIT);
704 					if (sp == 0) {
705 						error = ENOSPC;
706 						break;
707 					}
708 					if (notmapped) {
709 						error = md_malloc_move_ma(&m,
710 						    &ma_offs, sc->sectorsize,
711 						    (void *)sp, 0,
712 						    MD_MALLOC_MOVE_WRITE);
713 					} else if (vlist != NULL) {
714 						error = md_malloc_move_vlist(
715 						    &vlist, &ma_offs,
716 						    sc->sectorsize, (void *)sp,
717 						    0, MD_MALLOC_MOVE_WRITE);
718 					} else {
719 						bcopy(dst, (void *)sp,
720 						    sc->sectorsize);
721 					}
722 					error = s_write(sc->indir, secno, sp);
723 				} else {
724 					if (notmapped) {
725 						error = md_malloc_move_ma(&m,
726 						    &ma_offs, sc->sectorsize,
727 						    (void *)osp, 0,
728 						    MD_MALLOC_MOVE_WRITE);
729 					} else if (vlist != NULL) {
730 						error = md_malloc_move_vlist(
731 						    &vlist, &ma_offs,
732 						    sc->sectorsize, (void *)osp,
733 						    0, MD_MALLOC_MOVE_WRITE);
734 					} else {
735 						bcopy(dst, (void *)osp,
736 						    sc->sectorsize);
737 					}
738 					osp = 0;
739 				}
740 			}
741 		} else {
742 			error = EOPNOTSUPP;
743 		}
744 		if (osp > 255)
745 			uma_zfree(sc->uma, (void*)osp);
746 		if (error != 0)
747 			break;
748 		secno++;
749 		if (!notmapped && vlist == NULL)
750 			dst += sc->sectorsize;
751 	}
752 	bp->bio_resid = 0;
753 	return (error);
754 }
755 
756 static void
757 mdcopyto_vlist(void *src, bus_dma_segment_t *vlist, off_t offset, off_t len)
758 {
759 	off_t seg_len;
760 
761 	while (offset >= vlist->ds_len) {
762 		offset -= vlist->ds_len;
763 		vlist++;
764 	}
765 
766 	while (len != 0) {
767 		seg_len = omin(len, vlist->ds_len - offset);
768 		bcopy(src, (void *)(uintptr_t)(vlist->ds_addr + offset),
769 		    seg_len);
770 		offset = 0;
771 		src = (uint8_t *)src + seg_len;
772 		len -= seg_len;
773 		vlist++;
774 	}
775 }
776 
777 static void
778 mdcopyfrom_vlist(bus_dma_segment_t *vlist, off_t offset, void *dst, off_t len)
779 {
780 	off_t seg_len;
781 
782 	while (offset >= vlist->ds_len) {
783 		offset -= vlist->ds_len;
784 		vlist++;
785 	}
786 
787 	while (len != 0) {
788 		seg_len = omin(len, vlist->ds_len - offset);
789 		bcopy((void *)(uintptr_t)(vlist->ds_addr + offset), dst,
790 		    seg_len);
791 		offset = 0;
792 		dst = (uint8_t *)dst + seg_len;
793 		len -= seg_len;
794 		vlist++;
795 	}
796 }
797 
798 static int
799 mdstart_preload(struct md_s *sc, struct bio *bp)
800 {
801 	uint8_t *p;
802 
803 	p = sc->pl_ptr + bp->bio_offset;
804 	switch (bp->bio_cmd) {
805 	case BIO_READ:
806 		if ((bp->bio_flags & BIO_VLIST) != 0) {
807 			mdcopyto_vlist(p, (bus_dma_segment_t *)bp->bio_data,
808 			    bp->bio_ma_offset, bp->bio_length);
809 		} else {
810 			bcopy(p, bp->bio_data, bp->bio_length);
811 		}
812 		cpu_flush_dcache(bp->bio_data, bp->bio_length);
813 		break;
814 	case BIO_WRITE:
815 		if ((bp->bio_flags & BIO_VLIST) != 0) {
816 			mdcopyfrom_vlist((bus_dma_segment_t *)bp->bio_data,
817 			    bp->bio_ma_offset, p, bp->bio_length);
818 		} else {
819 			bcopy(bp->bio_data, p, bp->bio_length);
820 		}
821 		break;
822 	}
823 	bp->bio_resid = 0;
824 	return (0);
825 }
826 
827 static int
828 mdstart_vnode(struct md_s *sc, struct bio *bp)
829 {
830 	int error;
831 	struct uio auio;
832 	struct iovec aiov;
833 	struct iovec *piov;
834 	struct mount *mp;
835 	struct vnode *vp;
836 	struct buf *pb;
837 	bus_dma_segment_t *vlist;
838 	struct thread *td;
839 	off_t len, zerosize;
840 	int ma_offs;
841 
842 	switch (bp->bio_cmd) {
843 	case BIO_READ:
844 		auio.uio_rw = UIO_READ;
845 		break;
846 	case BIO_WRITE:
847 	case BIO_DELETE:
848 		auio.uio_rw = UIO_WRITE;
849 		break;
850 	case BIO_FLUSH:
851 		break;
852 	default:
853 		return (EOPNOTSUPP);
854 	}
855 
856 	td = curthread;
857 	vp = sc->vnode;
858 	pb = NULL;
859 	piov = NULL;
860 	ma_offs = bp->bio_ma_offset;
861 
862 	/*
863 	 * VNODE I/O
864 	 *
865 	 * If an error occurs, we set BIO_ERROR but we do not set
866 	 * B_INVAL because (for a write anyway), the buffer is
867 	 * still valid.
868 	 */
869 
870 	if (bp->bio_cmd == BIO_FLUSH) {
871 		(void) vn_start_write(vp, &mp, V_WAIT);
872 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
873 		error = VOP_FSYNC(vp, MNT_WAIT, td);
874 		VOP_UNLOCK(vp, 0);
875 		vn_finished_write(mp);
876 		return (error);
877 	}
878 
879 	auio.uio_offset = (vm_ooffset_t)bp->bio_offset;
880 	auio.uio_resid = bp->bio_length;
881 	auio.uio_segflg = UIO_SYSSPACE;
882 	auio.uio_td = td;
883 
884 	if (bp->bio_cmd == BIO_DELETE) {
885 		/*
886 		 * Emulate BIO_DELETE by writing zeros.
887 		 */
888 		zerosize = ZERO_REGION_SIZE -
889 		    (ZERO_REGION_SIZE % sc->sectorsize);
890 		auio.uio_iovcnt = howmany(bp->bio_length, zerosize);
891 		piov = malloc(sizeof(*piov) * auio.uio_iovcnt, M_MD, M_WAITOK);
892 		auio.uio_iov = piov;
893 		len = bp->bio_length;
894 		while (len > 0) {
895 			piov->iov_base = __DECONST(void *, zero_region);
896 			piov->iov_len = len;
897 			if (len > zerosize)
898 				piov->iov_len = zerosize;
899 			len -= piov->iov_len;
900 			piov++;
901 		}
902 		piov = auio.uio_iov;
903 	} else if ((bp->bio_flags & BIO_VLIST) != 0) {
904 		piov = malloc(sizeof(*piov) * bp->bio_ma_n, M_MD, M_WAITOK);
905 		auio.uio_iov = piov;
906 		vlist = (bus_dma_segment_t *)bp->bio_data;
907 		len = bp->bio_length;
908 		while (len > 0) {
909 			piov->iov_base = (void *)(uintptr_t)(vlist->ds_addr +
910 			    ma_offs);
911 			piov->iov_len = vlist->ds_len - ma_offs;
912 			if (piov->iov_len > len)
913 				piov->iov_len = len;
914 			len -= piov->iov_len;
915 			ma_offs = 0;
916 			vlist++;
917 			piov++;
918 		}
919 		auio.uio_iovcnt = piov - auio.uio_iov;
920 		piov = auio.uio_iov;
921 	} else if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
922 		pb = getpbuf(&md_vnode_pbuf_freecnt);
923 		pmap_qenter((vm_offset_t)pb->b_data, bp->bio_ma, bp->bio_ma_n);
924 		aiov.iov_base = (void *)((vm_offset_t)pb->b_data + ma_offs);
925 		aiov.iov_len = bp->bio_length;
926 		auio.uio_iov = &aiov;
927 		auio.uio_iovcnt = 1;
928 	} else {
929 		aiov.iov_base = bp->bio_data;
930 		aiov.iov_len = bp->bio_length;
931 		auio.uio_iov = &aiov;
932 		auio.uio_iovcnt = 1;
933 	}
934 	/*
935 	 * When reading set IO_DIRECT to try to avoid double-caching
936 	 * the data.  When writing IO_DIRECT is not optimal.
937 	 */
938 	if (auio.uio_rw == UIO_READ) {
939 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
940 		error = VOP_READ(vp, &auio, IO_DIRECT, sc->cred);
941 		VOP_UNLOCK(vp, 0);
942 	} else {
943 		(void) vn_start_write(vp, &mp, V_WAIT);
944 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
945 		error = VOP_WRITE(vp, &auio, sc->flags & MD_ASYNC ? 0 : IO_SYNC,
946 		    sc->cred);
947 		VOP_UNLOCK(vp, 0);
948 		vn_finished_write(mp);
949 	}
950 
951 	if (pb) {
952 		pmap_qremove((vm_offset_t)pb->b_data, bp->bio_ma_n);
953 		relpbuf(pb, &md_vnode_pbuf_freecnt);
954 	}
955 
956 	if (piov != NULL)
957 		free(piov, M_MD);
958 
959 	bp->bio_resid = auio.uio_resid;
960 	return (error);
961 }
962 
963 static int
964 mdstart_swap(struct md_s *sc, struct bio *bp)
965 {
966 	vm_page_t m;
967 	u_char *p;
968 	vm_pindex_t i, lastp;
969 	bus_dma_segment_t *vlist;
970 	int rv, ma_offs, offs, len, lastend;
971 
972 	switch (bp->bio_cmd) {
973 	case BIO_READ:
974 	case BIO_WRITE:
975 	case BIO_DELETE:
976 		break;
977 	default:
978 		return (EOPNOTSUPP);
979 	}
980 
981 	p = bp->bio_data;
982 	ma_offs = (bp->bio_flags & (BIO_UNMAPPED|BIO_VLIST)) != 0 ?
983 	    bp->bio_ma_offset : 0;
984 	vlist = (bp->bio_flags & BIO_VLIST) != 0 ?
985 	    (bus_dma_segment_t *)bp->bio_data : NULL;
986 
987 	/*
988 	 * offs is the offset at which to start operating on the
989 	 * next (ie, first) page.  lastp is the last page on
990 	 * which we're going to operate.  lastend is the ending
991 	 * position within that last page (ie, PAGE_SIZE if
992 	 * we're operating on complete aligned pages).
993 	 */
994 	offs = bp->bio_offset % PAGE_SIZE;
995 	lastp = (bp->bio_offset + bp->bio_length - 1) / PAGE_SIZE;
996 	lastend = (bp->bio_offset + bp->bio_length - 1) % PAGE_SIZE + 1;
997 
998 	rv = VM_PAGER_OK;
999 	VM_OBJECT_WLOCK(sc->object);
1000 	vm_object_pip_add(sc->object, 1);
1001 	for (i = bp->bio_offset / PAGE_SIZE; i <= lastp; i++) {
1002 		len = ((i == lastp) ? lastend : PAGE_SIZE) - offs;
1003 		m = vm_page_grab(sc->object, i, VM_ALLOC_SYSTEM);
1004 		if (bp->bio_cmd == BIO_READ) {
1005 			if (m->valid == VM_PAGE_BITS_ALL)
1006 				rv = VM_PAGER_OK;
1007 			else
1008 				rv = vm_pager_get_pages(sc->object, &m, 1, 0);
1009 			if (rv == VM_PAGER_ERROR) {
1010 				vm_page_xunbusy(m);
1011 				break;
1012 			} else if (rv == VM_PAGER_FAIL) {
1013 				/*
1014 				 * Pager does not have the page.  Zero
1015 				 * the allocated page, and mark it as
1016 				 * valid. Do not set dirty, the page
1017 				 * can be recreated if thrown out.
1018 				 */
1019 				pmap_zero_page(m);
1020 				m->valid = VM_PAGE_BITS_ALL;
1021 			}
1022 			if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
1023 				pmap_copy_pages(&m, offs, bp->bio_ma,
1024 				    ma_offs, len);
1025 			} else if ((bp->bio_flags & BIO_VLIST) != 0) {
1026 				physcopyout_vlist(VM_PAGE_TO_PHYS(m) + offs,
1027 				    vlist, ma_offs, len);
1028 				cpu_flush_dcache(p, len);
1029 			} else {
1030 				physcopyout(VM_PAGE_TO_PHYS(m) + offs, p, len);
1031 				cpu_flush_dcache(p, len);
1032 			}
1033 		} else if (bp->bio_cmd == BIO_WRITE) {
1034 			if (len != PAGE_SIZE && m->valid != VM_PAGE_BITS_ALL)
1035 				rv = vm_pager_get_pages(sc->object, &m, 1, 0);
1036 			else
1037 				rv = VM_PAGER_OK;
1038 			if (rv == VM_PAGER_ERROR) {
1039 				vm_page_xunbusy(m);
1040 				break;
1041 			}
1042 			if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
1043 				pmap_copy_pages(bp->bio_ma, ma_offs, &m,
1044 				    offs, len);
1045 			} else if ((bp->bio_flags & BIO_VLIST) != 0) {
1046 				physcopyin_vlist(vlist, ma_offs,
1047 				    VM_PAGE_TO_PHYS(m) + offs, len);
1048 			} else {
1049 				physcopyin(p, VM_PAGE_TO_PHYS(m) + offs, len);
1050 			}
1051 			m->valid = VM_PAGE_BITS_ALL;
1052 		} else if (bp->bio_cmd == BIO_DELETE) {
1053 			if (len != PAGE_SIZE && m->valid != VM_PAGE_BITS_ALL)
1054 				rv = vm_pager_get_pages(sc->object, &m, 1, 0);
1055 			else
1056 				rv = VM_PAGER_OK;
1057 			if (rv == VM_PAGER_ERROR) {
1058 				vm_page_xunbusy(m);
1059 				break;
1060 			}
1061 			if (len != PAGE_SIZE) {
1062 				pmap_zero_page_area(m, offs, len);
1063 				vm_page_clear_dirty(m, offs, len);
1064 				m->valid = VM_PAGE_BITS_ALL;
1065 			} else
1066 				vm_pager_page_unswapped(m);
1067 		}
1068 		vm_page_xunbusy(m);
1069 		vm_page_lock(m);
1070 		if (bp->bio_cmd == BIO_DELETE && len == PAGE_SIZE)
1071 			vm_page_free(m);
1072 		else
1073 			vm_page_activate(m);
1074 		vm_page_unlock(m);
1075 		if (bp->bio_cmd == BIO_WRITE) {
1076 			vm_page_dirty(m);
1077 			vm_pager_page_unswapped(m);
1078 		}
1079 
1080 		/* Actions on further pages start at offset 0 */
1081 		p += PAGE_SIZE - offs;
1082 		offs = 0;
1083 		ma_offs += len;
1084 	}
1085 	vm_object_pip_wakeup(sc->object);
1086 	VM_OBJECT_WUNLOCK(sc->object);
1087 	return (rv != VM_PAGER_ERROR ? 0 : ENOSPC);
1088 }
1089 
1090 static int
1091 mdstart_null(struct md_s *sc, struct bio *bp)
1092 {
1093 
1094 	switch (bp->bio_cmd) {
1095 	case BIO_READ:
1096 		bzero(bp->bio_data, bp->bio_length);
1097 		cpu_flush_dcache(bp->bio_data, bp->bio_length);
1098 		break;
1099 	case BIO_WRITE:
1100 		break;
1101 	}
1102 	bp->bio_resid = 0;
1103 	return (0);
1104 }
1105 
1106 static void
1107 md_kthread(void *arg)
1108 {
1109 	struct md_s *sc;
1110 	struct bio *bp;
1111 	int error;
1112 
1113 	sc = arg;
1114 	thread_lock(curthread);
1115 	sched_prio(curthread, PRIBIO);
1116 	thread_unlock(curthread);
1117 	if (sc->type == MD_VNODE)
1118 		curthread->td_pflags |= TDP_NORUNNINGBUF;
1119 
1120 	for (;;) {
1121 		mtx_lock(&sc->queue_mtx);
1122 		if (sc->flags & MD_SHUTDOWN) {
1123 			sc->flags |= MD_EXITING;
1124 			mtx_unlock(&sc->queue_mtx);
1125 			kproc_exit(0);
1126 		}
1127 		bp = bioq_takefirst(&sc->bio_queue);
1128 		if (!bp) {
1129 			msleep(sc, &sc->queue_mtx, PRIBIO | PDROP, "mdwait", 0);
1130 			continue;
1131 		}
1132 		mtx_unlock(&sc->queue_mtx);
1133 		if (bp->bio_cmd == BIO_GETATTR) {
1134 			if ((sc->fwsectors && sc->fwheads &&
1135 			    (g_handleattr_int(bp, "GEOM::fwsectors",
1136 			    sc->fwsectors) ||
1137 			    g_handleattr_int(bp, "GEOM::fwheads",
1138 			    sc->fwheads))) ||
1139 			    g_handleattr_int(bp, "GEOM::candelete", 1))
1140 				error = -1;
1141 			else
1142 				error = EOPNOTSUPP;
1143 		} else {
1144 			error = sc->start(sc, bp);
1145 		}
1146 
1147 		if (error != -1) {
1148 			bp->bio_completed = bp->bio_length;
1149 			if ((bp->bio_cmd == BIO_READ) || (bp->bio_cmd == BIO_WRITE))
1150 				devstat_end_transaction_bio(sc->devstat, bp);
1151 			g_io_deliver(bp, error);
1152 		}
1153 	}
1154 }
1155 
1156 static struct md_s *
1157 mdfind(int unit)
1158 {
1159 	struct md_s *sc;
1160 
1161 	LIST_FOREACH(sc, &md_softc_list, list) {
1162 		if (sc->unit == unit)
1163 			break;
1164 	}
1165 	return (sc);
1166 }
1167 
1168 static struct md_s *
1169 mdnew(int unit, int *errp, enum md_types type)
1170 {
1171 	struct md_s *sc;
1172 	int error;
1173 
1174 	*errp = 0;
1175 	if (unit == -1)
1176 		unit = alloc_unr(md_uh);
1177 	else
1178 		unit = alloc_unr_specific(md_uh, unit);
1179 
1180 	if (unit == -1) {
1181 		*errp = EBUSY;
1182 		return (NULL);
1183 	}
1184 
1185 	sc = (struct md_s *)malloc(sizeof *sc, M_MD, M_WAITOK | M_ZERO);
1186 	sc->type = type;
1187 	bioq_init(&sc->bio_queue);
1188 	mtx_init(&sc->queue_mtx, "md bio queue", NULL, MTX_DEF);
1189 	mtx_init(&sc->stat_mtx, "md stat", NULL, MTX_DEF);
1190 	sc->unit = unit;
1191 	sprintf(sc->name, "md%d", unit);
1192 	LIST_INSERT_HEAD(&md_softc_list, sc, list);
1193 	error = kproc_create(md_kthread, sc, &sc->procp, 0, 0,"%s", sc->name);
1194 	if (error == 0)
1195 		return (sc);
1196 	LIST_REMOVE(sc, list);
1197 	mtx_destroy(&sc->stat_mtx);
1198 	mtx_destroy(&sc->queue_mtx);
1199 	free_unr(md_uh, sc->unit);
1200 	free(sc, M_MD);
1201 	*errp = error;
1202 	return (NULL);
1203 }
1204 
1205 static void
1206 mdinit(struct md_s *sc)
1207 {
1208 	struct g_geom *gp;
1209 	struct g_provider *pp;
1210 
1211 	g_topology_lock();
1212 	gp = g_new_geomf(&g_md_class, "md%d", sc->unit);
1213 	gp->softc = sc;
1214 	pp = g_new_providerf(gp, "md%d", sc->unit);
1215 	pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE;
1216 	pp->mediasize = sc->mediasize;
1217 	pp->sectorsize = sc->sectorsize;
1218 	switch (sc->type) {
1219 	case MD_MALLOC:
1220 	case MD_VNODE:
1221 	case MD_SWAP:
1222 		pp->flags |= G_PF_ACCEPT_UNMAPPED;
1223 		break;
1224 	case MD_PRELOAD:
1225 	case MD_NULL:
1226 		break;
1227 	}
1228 	sc->gp = gp;
1229 	sc->pp = pp;
1230 	g_error_provider(pp, 0);
1231 	g_topology_unlock();
1232 	sc->devstat = devstat_new_entry("md", sc->unit, sc->sectorsize,
1233 	    DEVSTAT_ALL_SUPPORTED, DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
1234 }
1235 
1236 static int
1237 mdcreate_malloc(struct md_s *sc, struct md_ioctl *mdio)
1238 {
1239 	uintptr_t sp;
1240 	int error;
1241 	off_t u;
1242 
1243 	error = 0;
1244 	if (mdio->md_options & ~(MD_AUTOUNIT | MD_COMPRESS | MD_RESERVE))
1245 		return (EINVAL);
1246 	if (mdio->md_sectorsize != 0 && !powerof2(mdio->md_sectorsize))
1247 		return (EINVAL);
1248 	/* Compression doesn't make sense if we have reserved space */
1249 	if (mdio->md_options & MD_RESERVE)
1250 		mdio->md_options &= ~MD_COMPRESS;
1251 	if (mdio->md_fwsectors != 0)
1252 		sc->fwsectors = mdio->md_fwsectors;
1253 	if (mdio->md_fwheads != 0)
1254 		sc->fwheads = mdio->md_fwheads;
1255 	sc->flags = mdio->md_options & (MD_COMPRESS | MD_FORCE);
1256 	sc->indir = dimension(sc->mediasize / sc->sectorsize);
1257 	sc->uma = uma_zcreate(sc->name, sc->sectorsize, NULL, NULL, NULL, NULL,
1258 	    0x1ff, 0);
1259 	if (mdio->md_options & MD_RESERVE) {
1260 		off_t nsectors;
1261 
1262 		nsectors = sc->mediasize / sc->sectorsize;
1263 		for (u = 0; u < nsectors; u++) {
1264 			sp = (uintptr_t)uma_zalloc(sc->uma, (md_malloc_wait ?
1265 			    M_WAITOK : M_NOWAIT) | M_ZERO);
1266 			if (sp != 0)
1267 				error = s_write(sc->indir, u, sp);
1268 			else
1269 				error = ENOMEM;
1270 			if (error != 0)
1271 				break;
1272 		}
1273 	}
1274 	return (error);
1275 }
1276 
1277 
1278 static int
1279 mdsetcred(struct md_s *sc, struct ucred *cred)
1280 {
1281 	char *tmpbuf;
1282 	int error = 0;
1283 
1284 	/*
1285 	 * Set credits in our softc
1286 	 */
1287 
1288 	if (sc->cred)
1289 		crfree(sc->cred);
1290 	sc->cred = crhold(cred);
1291 
1292 	/*
1293 	 * Horrible kludge to establish credentials for NFS  XXX.
1294 	 */
1295 
1296 	if (sc->vnode) {
1297 		struct uio auio;
1298 		struct iovec aiov;
1299 
1300 		tmpbuf = malloc(sc->sectorsize, M_TEMP, M_WAITOK);
1301 		bzero(&auio, sizeof(auio));
1302 
1303 		aiov.iov_base = tmpbuf;
1304 		aiov.iov_len = sc->sectorsize;
1305 		auio.uio_iov = &aiov;
1306 		auio.uio_iovcnt = 1;
1307 		auio.uio_offset = 0;
1308 		auio.uio_rw = UIO_READ;
1309 		auio.uio_segflg = UIO_SYSSPACE;
1310 		auio.uio_resid = aiov.iov_len;
1311 		vn_lock(sc->vnode, LK_EXCLUSIVE | LK_RETRY);
1312 		error = VOP_READ(sc->vnode, &auio, 0, sc->cred);
1313 		VOP_UNLOCK(sc->vnode, 0);
1314 		free(tmpbuf, M_TEMP);
1315 	}
1316 	return (error);
1317 }
1318 
1319 static int
1320 mdcreate_vnode(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
1321 {
1322 	struct vattr vattr;
1323 	struct nameidata nd;
1324 	char *fname;
1325 	int error, flags;
1326 
1327 	/*
1328 	 * Kernel-originated requests must have the filename appended
1329 	 * to the mdio structure to protect against malicious software.
1330 	 */
1331 	fname = mdio->md_file;
1332 	if ((void *)fname != (void *)(mdio + 1)) {
1333 		error = copyinstr(fname, sc->file, sizeof(sc->file), NULL);
1334 		if (error != 0)
1335 			return (error);
1336 	} else
1337 		strlcpy(sc->file, fname, sizeof(sc->file));
1338 
1339 	/*
1340 	 * If the user specified that this is a read only device, don't
1341 	 * set the FWRITE mask before trying to open the backing store.
1342 	 */
1343 	flags = FREAD | ((mdio->md_options & MD_READONLY) ? 0 : FWRITE);
1344 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, sc->file, td);
1345 	error = vn_open(&nd, &flags, 0, NULL);
1346 	if (error != 0)
1347 		return (error);
1348 	NDFREE(&nd, NDF_ONLY_PNBUF);
1349 	if (nd.ni_vp->v_type != VREG) {
1350 		error = EINVAL;
1351 		goto bad;
1352 	}
1353 	error = VOP_GETATTR(nd.ni_vp, &vattr, td->td_ucred);
1354 	if (error != 0)
1355 		goto bad;
1356 	if (VOP_ISLOCKED(nd.ni_vp) != LK_EXCLUSIVE) {
1357 		vn_lock(nd.ni_vp, LK_UPGRADE | LK_RETRY);
1358 		if (nd.ni_vp->v_iflag & VI_DOOMED) {
1359 			/* Forced unmount. */
1360 			error = EBADF;
1361 			goto bad;
1362 		}
1363 	}
1364 	nd.ni_vp->v_vflag |= VV_MD;
1365 	VOP_UNLOCK(nd.ni_vp, 0);
1366 
1367 	if (mdio->md_fwsectors != 0)
1368 		sc->fwsectors = mdio->md_fwsectors;
1369 	if (mdio->md_fwheads != 0)
1370 		sc->fwheads = mdio->md_fwheads;
1371 	sc->flags = mdio->md_options & (MD_FORCE | MD_ASYNC);
1372 	if (!(flags & FWRITE))
1373 		sc->flags |= MD_READONLY;
1374 	sc->vnode = nd.ni_vp;
1375 
1376 	error = mdsetcred(sc, td->td_ucred);
1377 	if (error != 0) {
1378 		sc->vnode = NULL;
1379 		vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1380 		nd.ni_vp->v_vflag &= ~VV_MD;
1381 		goto bad;
1382 	}
1383 	return (0);
1384 bad:
1385 	VOP_UNLOCK(nd.ni_vp, 0);
1386 	(void)vn_close(nd.ni_vp, flags, td->td_ucred, td);
1387 	return (error);
1388 }
1389 
1390 static int
1391 mddestroy(struct md_s *sc, struct thread *td)
1392 {
1393 
1394 	if (sc->gp) {
1395 		sc->gp->softc = NULL;
1396 		g_topology_lock();
1397 		g_wither_geom(sc->gp, ENXIO);
1398 		g_topology_unlock();
1399 		sc->gp = NULL;
1400 		sc->pp = NULL;
1401 	}
1402 	if (sc->devstat) {
1403 		devstat_remove_entry(sc->devstat);
1404 		sc->devstat = NULL;
1405 	}
1406 	mtx_lock(&sc->queue_mtx);
1407 	sc->flags |= MD_SHUTDOWN;
1408 	wakeup(sc);
1409 	while (!(sc->flags & MD_EXITING))
1410 		msleep(sc->procp, &sc->queue_mtx, PRIBIO, "mddestroy", hz / 10);
1411 	mtx_unlock(&sc->queue_mtx);
1412 	mtx_destroy(&sc->stat_mtx);
1413 	mtx_destroy(&sc->queue_mtx);
1414 	if (sc->vnode != NULL) {
1415 		vn_lock(sc->vnode, LK_EXCLUSIVE | LK_RETRY);
1416 		sc->vnode->v_vflag &= ~VV_MD;
1417 		VOP_UNLOCK(sc->vnode, 0);
1418 		(void)vn_close(sc->vnode, sc->flags & MD_READONLY ?
1419 		    FREAD : (FREAD|FWRITE), sc->cred, td);
1420 	}
1421 	if (sc->cred != NULL)
1422 		crfree(sc->cred);
1423 	if (sc->object != NULL)
1424 		vm_object_deallocate(sc->object);
1425 	if (sc->indir)
1426 		destroy_indir(sc, sc->indir);
1427 	if (sc->uma)
1428 		uma_zdestroy(sc->uma);
1429 
1430 	LIST_REMOVE(sc, list);
1431 	free_unr(md_uh, sc->unit);
1432 	free(sc, M_MD);
1433 	return (0);
1434 }
1435 
1436 static int
1437 mdresize(struct md_s *sc, struct md_ioctl *mdio)
1438 {
1439 	int error, res;
1440 	vm_pindex_t oldpages, newpages;
1441 
1442 	switch (sc->type) {
1443 	case MD_VNODE:
1444 	case MD_NULL:
1445 		break;
1446 	case MD_SWAP:
1447 		if (mdio->md_mediasize <= 0 ||
1448 		    (mdio->md_mediasize % PAGE_SIZE) != 0)
1449 			return (EDOM);
1450 		oldpages = OFF_TO_IDX(round_page(sc->mediasize));
1451 		newpages = OFF_TO_IDX(round_page(mdio->md_mediasize));
1452 		if (newpages < oldpages) {
1453 			VM_OBJECT_WLOCK(sc->object);
1454 			vm_object_page_remove(sc->object, newpages, 0, 0);
1455 			swap_pager_freespace(sc->object, newpages,
1456 			    oldpages - newpages);
1457 			swap_release_by_cred(IDX_TO_OFF(oldpages -
1458 			    newpages), sc->cred);
1459 			sc->object->charge = IDX_TO_OFF(newpages);
1460 			sc->object->size = newpages;
1461 			VM_OBJECT_WUNLOCK(sc->object);
1462 		} else if (newpages > oldpages) {
1463 			res = swap_reserve_by_cred(IDX_TO_OFF(newpages -
1464 			    oldpages), sc->cred);
1465 			if (!res)
1466 				return (ENOMEM);
1467 			if ((mdio->md_options & MD_RESERVE) ||
1468 			    (sc->flags & MD_RESERVE)) {
1469 				error = swap_pager_reserve(sc->object,
1470 				    oldpages, newpages - oldpages);
1471 				if (error < 0) {
1472 					swap_release_by_cred(
1473 					    IDX_TO_OFF(newpages - oldpages),
1474 					    sc->cred);
1475 					return (EDOM);
1476 				}
1477 			}
1478 			VM_OBJECT_WLOCK(sc->object);
1479 			sc->object->charge = IDX_TO_OFF(newpages);
1480 			sc->object->size = newpages;
1481 			VM_OBJECT_WUNLOCK(sc->object);
1482 		}
1483 		break;
1484 	default:
1485 		return (EOPNOTSUPP);
1486 	}
1487 
1488 	sc->mediasize = mdio->md_mediasize;
1489 	g_topology_lock();
1490 	g_resize_provider(sc->pp, sc->mediasize);
1491 	g_topology_unlock();
1492 	return (0);
1493 }
1494 
1495 static int
1496 mdcreate_swap(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
1497 {
1498 	vm_ooffset_t npage;
1499 	int error;
1500 
1501 	/*
1502 	 * Range check.  Disallow negative sizes and sizes not being
1503 	 * multiple of page size.
1504 	 */
1505 	if (sc->mediasize <= 0 || (sc->mediasize % PAGE_SIZE) != 0)
1506 		return (EDOM);
1507 
1508 	/*
1509 	 * Allocate an OBJT_SWAP object.
1510 	 *
1511 	 * Note the truncation.
1512 	 */
1513 
1514 	npage = mdio->md_mediasize / PAGE_SIZE;
1515 	if (mdio->md_fwsectors != 0)
1516 		sc->fwsectors = mdio->md_fwsectors;
1517 	if (mdio->md_fwheads != 0)
1518 		sc->fwheads = mdio->md_fwheads;
1519 	sc->object = vm_pager_allocate(OBJT_SWAP, NULL, PAGE_SIZE * npage,
1520 	    VM_PROT_DEFAULT, 0, td->td_ucred);
1521 	if (sc->object == NULL)
1522 		return (ENOMEM);
1523 	sc->flags = mdio->md_options & (MD_FORCE | MD_RESERVE);
1524 	if (mdio->md_options & MD_RESERVE) {
1525 		if (swap_pager_reserve(sc->object, 0, npage) < 0) {
1526 			error = EDOM;
1527 			goto finish;
1528 		}
1529 	}
1530 	error = mdsetcred(sc, td->td_ucred);
1531  finish:
1532 	if (error != 0) {
1533 		vm_object_deallocate(sc->object);
1534 		sc->object = NULL;
1535 	}
1536 	return (error);
1537 }
1538 
1539 static int
1540 mdcreate_null(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
1541 {
1542 
1543 	/*
1544 	 * Range check.  Disallow negative sizes and sizes not being
1545 	 * multiple of page size.
1546 	 */
1547 	if (sc->mediasize <= 0 || (sc->mediasize % PAGE_SIZE) != 0)
1548 		return (EDOM);
1549 
1550 	return (0);
1551 }
1552 
1553 static int
1554 xmdctlioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
1555 {
1556 	struct md_ioctl *mdio;
1557 	struct md_s *sc;
1558 	int error, i;
1559 	unsigned sectsize;
1560 
1561 	if (md_debug)
1562 		printf("mdctlioctl(%s %lx %p %x %p)\n",
1563 			devtoname(dev), cmd, addr, flags, td);
1564 
1565 	mdio = (struct md_ioctl *)addr;
1566 	if (mdio->md_version != MDIOVERSION)
1567 		return (EINVAL);
1568 
1569 	/*
1570 	 * We assert the version number in the individual ioctl
1571 	 * handlers instead of out here because (a) it is possible we
1572 	 * may add another ioctl in the future which doesn't read an
1573 	 * mdio, and (b) the correct return value for an unknown ioctl
1574 	 * is ENOIOCTL, not EINVAL.
1575 	 */
1576 	error = 0;
1577 	switch (cmd) {
1578 	case MDIOCATTACH:
1579 		switch (mdio->md_type) {
1580 		case MD_MALLOC:
1581 		case MD_PRELOAD:
1582 		case MD_VNODE:
1583 		case MD_SWAP:
1584 		case MD_NULL:
1585 			break;
1586 		default:
1587 			return (EINVAL);
1588 		}
1589 		if (mdio->md_sectorsize == 0)
1590 			sectsize = DEV_BSIZE;
1591 		else
1592 			sectsize = mdio->md_sectorsize;
1593 		if (sectsize > MAXPHYS || mdio->md_mediasize < sectsize)
1594 			return (EINVAL);
1595 		if (mdio->md_options & MD_AUTOUNIT)
1596 			sc = mdnew(-1, &error, mdio->md_type);
1597 		else {
1598 			if (mdio->md_unit > INT_MAX)
1599 				return (EINVAL);
1600 			sc = mdnew(mdio->md_unit, &error, mdio->md_type);
1601 		}
1602 		if (sc == NULL)
1603 			return (error);
1604 		if (mdio->md_options & MD_AUTOUNIT)
1605 			mdio->md_unit = sc->unit;
1606 		sc->mediasize = mdio->md_mediasize;
1607 		sc->sectorsize = sectsize;
1608 		error = EDOOFUS;
1609 		switch (sc->type) {
1610 		case MD_MALLOC:
1611 			sc->start = mdstart_malloc;
1612 			error = mdcreate_malloc(sc, mdio);
1613 			break;
1614 		case MD_PRELOAD:
1615 			/*
1616 			 * We disallow attaching preloaded memory disks via
1617 			 * ioctl. Preloaded memory disks are automatically
1618 			 * attached in g_md_init().
1619 			 */
1620 			error = EOPNOTSUPP;
1621 			break;
1622 		case MD_VNODE:
1623 			sc->start = mdstart_vnode;
1624 			error = mdcreate_vnode(sc, mdio, td);
1625 			break;
1626 		case MD_SWAP:
1627 			sc->start = mdstart_swap;
1628 			error = mdcreate_swap(sc, mdio, td);
1629 			break;
1630 		case MD_NULL:
1631 			sc->start = mdstart_null;
1632 			error = mdcreate_null(sc, mdio, td);
1633 			break;
1634 		}
1635 		if (error != 0) {
1636 			mddestroy(sc, td);
1637 			return (error);
1638 		}
1639 
1640 		/* Prune off any residual fractional sector */
1641 		i = sc->mediasize % sc->sectorsize;
1642 		sc->mediasize -= i;
1643 
1644 		mdinit(sc);
1645 		return (0);
1646 	case MDIOCDETACH:
1647 		if (mdio->md_mediasize != 0 ||
1648 		    (mdio->md_options & ~MD_FORCE) != 0)
1649 			return (EINVAL);
1650 
1651 		sc = mdfind(mdio->md_unit);
1652 		if (sc == NULL)
1653 			return (ENOENT);
1654 		if (sc->opencount != 0 && !(sc->flags & MD_FORCE) &&
1655 		    !(mdio->md_options & MD_FORCE))
1656 			return (EBUSY);
1657 		return (mddestroy(sc, td));
1658 	case MDIOCRESIZE:
1659 		if ((mdio->md_options & ~(MD_FORCE | MD_RESERVE)) != 0)
1660 			return (EINVAL);
1661 
1662 		sc = mdfind(mdio->md_unit);
1663 		if (sc == NULL)
1664 			return (ENOENT);
1665 		if (mdio->md_mediasize < sc->sectorsize)
1666 			return (EINVAL);
1667 		if (mdio->md_mediasize < sc->mediasize &&
1668 		    !(sc->flags & MD_FORCE) &&
1669 		    !(mdio->md_options & MD_FORCE))
1670 			return (EBUSY);
1671 		return (mdresize(sc, mdio));
1672 	case MDIOCQUERY:
1673 		sc = mdfind(mdio->md_unit);
1674 		if (sc == NULL)
1675 			return (ENOENT);
1676 		mdio->md_type = sc->type;
1677 		mdio->md_options = sc->flags;
1678 		mdio->md_mediasize = sc->mediasize;
1679 		mdio->md_sectorsize = sc->sectorsize;
1680 		if (sc->type == MD_VNODE)
1681 			error = copyout(sc->file, mdio->md_file,
1682 			    strlen(sc->file) + 1);
1683 		return (error);
1684 	case MDIOCLIST:
1685 		i = 1;
1686 		LIST_FOREACH(sc, &md_softc_list, list) {
1687 			if (i == MDNPAD - 1)
1688 				mdio->md_pad[i] = -1;
1689 			else
1690 				mdio->md_pad[i++] = sc->unit;
1691 		}
1692 		mdio->md_pad[0] = i - 1;
1693 		return (0);
1694 	default:
1695 		return (ENOIOCTL);
1696 	};
1697 }
1698 
1699 static int
1700 mdctlioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
1701 {
1702 	int error;
1703 
1704 	sx_xlock(&md_sx);
1705 	error = xmdctlioctl(dev, cmd, addr, flags, td);
1706 	sx_xunlock(&md_sx);
1707 	return (error);
1708 }
1709 
1710 static void
1711 md_preloaded(u_char *image, size_t length, const char *name)
1712 {
1713 	struct md_s *sc;
1714 	int error;
1715 
1716 	sc = mdnew(-1, &error, MD_PRELOAD);
1717 	if (sc == NULL)
1718 		return;
1719 	sc->mediasize = length;
1720 	sc->sectorsize = DEV_BSIZE;
1721 	sc->pl_ptr = image;
1722 	sc->pl_len = length;
1723 	sc->start = mdstart_preload;
1724 #ifdef MD_ROOT
1725 	if (sc->unit == 0)
1726 		rootdevnames[0] = MD_ROOT_FSTYPE ":/dev/md0";
1727 #endif
1728 	mdinit(sc);
1729 	if (name != NULL) {
1730 		printf("%s%d: Preloaded image <%s> %zd bytes at %p\n",
1731 		    MD_NAME, sc->unit, name, length, image);
1732 	} else {
1733 		printf("%s%d: Embedded image %zd bytes at %p\n",
1734 		    MD_NAME, sc->unit, length, image);
1735 	}
1736 }
1737 
1738 static void
1739 g_md_init(struct g_class *mp __unused)
1740 {
1741 	caddr_t mod;
1742 	u_char *ptr, *name, *type;
1743 	unsigned len;
1744 	int i;
1745 
1746 	/* figure out log2(NINDIR) */
1747 	for (i = NINDIR, nshift = -1; i; nshift++)
1748 		i >>= 1;
1749 
1750 	mod = NULL;
1751 	sx_init(&md_sx, "MD config lock");
1752 	g_topology_unlock();
1753 	md_uh = new_unrhdr(0, INT_MAX, NULL);
1754 #ifdef MD_ROOT
1755 	if (mfs_root_size != 0) {
1756 		sx_xlock(&md_sx);
1757 		md_preloaded(__DEVOLATILE(u_char *, &mfs_root), mfs_root_size,
1758 		    NULL);
1759 		sx_xunlock(&md_sx);
1760 	}
1761 #endif
1762 	/* XXX: are preload_* static or do they need Giant ? */
1763 	while ((mod = preload_search_next_name(mod)) != NULL) {
1764 		name = (char *)preload_search_info(mod, MODINFO_NAME);
1765 		if (name == NULL)
1766 			continue;
1767 		type = (char *)preload_search_info(mod, MODINFO_TYPE);
1768 		if (type == NULL)
1769 			continue;
1770 		if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
1771 			continue;
1772 		ptr = preload_fetch_addr(mod);
1773 		len = preload_fetch_size(mod);
1774 		if (ptr != NULL && len != 0) {
1775 			sx_xlock(&md_sx);
1776 			md_preloaded(ptr, len, name);
1777 			sx_xunlock(&md_sx);
1778 		}
1779 	}
1780 	md_vnode_pbuf_freecnt = nswbuf / 10;
1781 	status_dev = make_dev(&mdctl_cdevsw, INT_MAX, UID_ROOT, GID_WHEEL,
1782 	    0600, MDCTL_NAME);
1783 	g_topology_lock();
1784 }
1785 
1786 static void
1787 g_md_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1788     struct g_consumer *cp __unused, struct g_provider *pp)
1789 {
1790 	struct md_s *mp;
1791 	char *type;
1792 
1793 	mp = gp->softc;
1794 	if (mp == NULL)
1795 		return;
1796 
1797 	switch (mp->type) {
1798 	case MD_MALLOC:
1799 		type = "malloc";
1800 		break;
1801 	case MD_PRELOAD:
1802 		type = "preload";
1803 		break;
1804 	case MD_VNODE:
1805 		type = "vnode";
1806 		break;
1807 	case MD_SWAP:
1808 		type = "swap";
1809 		break;
1810 	case MD_NULL:
1811 		type = "null";
1812 		break;
1813 	default:
1814 		type = "unknown";
1815 		break;
1816 	}
1817 
1818 	if (pp != NULL) {
1819 		if (indent == NULL) {
1820 			sbuf_printf(sb, " u %d", mp->unit);
1821 			sbuf_printf(sb, " s %ju", (uintmax_t) mp->sectorsize);
1822 			sbuf_printf(sb, " f %ju", (uintmax_t) mp->fwheads);
1823 			sbuf_printf(sb, " fs %ju", (uintmax_t) mp->fwsectors);
1824 			sbuf_printf(sb, " l %ju", (uintmax_t) mp->mediasize);
1825 			sbuf_printf(sb, " t %s", type);
1826 			if (mp->type == MD_VNODE && mp->vnode != NULL)
1827 				sbuf_printf(sb, " file %s", mp->file);
1828 		} else {
1829 			sbuf_printf(sb, "%s<unit>%d</unit>\n", indent,
1830 			    mp->unit);
1831 			sbuf_printf(sb, "%s<sectorsize>%ju</sectorsize>\n",
1832 			    indent, (uintmax_t) mp->sectorsize);
1833 			sbuf_printf(sb, "%s<fwheads>%ju</fwheads>\n",
1834 			    indent, (uintmax_t) mp->fwheads);
1835 			sbuf_printf(sb, "%s<fwsectors>%ju</fwsectors>\n",
1836 			    indent, (uintmax_t) mp->fwsectors);
1837 			sbuf_printf(sb, "%s<length>%ju</length>\n",
1838 			    indent, (uintmax_t) mp->mediasize);
1839 			sbuf_printf(sb, "%s<compression>%s</compression>\n", indent,
1840 			    (mp->flags & MD_COMPRESS) == 0 ? "off": "on");
1841 			sbuf_printf(sb, "%s<access>%s</access>\n", indent,
1842 			    (mp->flags & MD_READONLY) == 0 ? "read-write":
1843 			    "read-only");
1844 			sbuf_printf(sb, "%s<type>%s</type>\n", indent,
1845 			    type);
1846 			if (mp->type == MD_VNODE && mp->vnode != NULL) {
1847 				sbuf_printf(sb, "%s<file>", indent);
1848 				g_conf_printf_escaped(sb, "%s", mp->file);
1849 				sbuf_printf(sb, "</file>\n");
1850 			}
1851 		}
1852 	}
1853 }
1854 
1855 static void
1856 g_md_fini(struct g_class *mp __unused)
1857 {
1858 
1859 	sx_destroy(&md_sx);
1860 	if (status_dev != NULL)
1861 		destroy_dev(status_dev);
1862 	delete_unrhdr(md_uh);
1863 }
1864