xref: /freebsd/sys/cam/ctl/ctl_backend_block.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2003 Silicon Graphics International Corp.
5  * Copyright (c) 2009-2011 Spectra Logic Corporation
6  * Copyright (c) 2012 The FreeBSD Foundation
7  * Copyright (c) 2014-2015 Alexander Motin <mav@FreeBSD.org>
8  * All rights reserved.
9  *
10  * Portions of this software were developed by Edward Tomasz Napierala
11  * under sponsorship from the FreeBSD Foundation.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions, and the following disclaimer,
18  *    without modification.
19  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
20  *    substantially similar to the "NO WARRANTY" disclaimer below
21  *    ("Disclaimer") and any redistribution must be conditioned upon
22  *    including a substantially similar Disclaimer requirement for further
23  *    binary redistribution.
24  *
25  * NO WARRANTY
26  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
29  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
30  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
34  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
35  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGES.
37  *
38  * $Id: //depot/users/kenm/FreeBSD-test2/sys/cam/ctl/ctl_backend_block.c#5 $
39  */
40 /*
41  * CAM Target Layer driver backend for block devices.
42  *
43  * Author: Ken Merry <ken@FreeBSD.org>
44  */
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
51 #include <sys/types.h>
52 #include <sys/kthread.h>
53 #include <sys/bio.h>
54 #include <sys/fcntl.h>
55 #include <sys/limits.h>
56 #include <sys/lock.h>
57 #include <sys/mutex.h>
58 #include <sys/condvar.h>
59 #include <sys/malloc.h>
60 #include <sys/conf.h>
61 #include <sys/ioccom.h>
62 #include <sys/queue.h>
63 #include <sys/sbuf.h>
64 #include <sys/endian.h>
65 #include <sys/uio.h>
66 #include <sys/buf.h>
67 #include <sys/taskqueue.h>
68 #include <sys/vnode.h>
69 #include <sys/namei.h>
70 #include <sys/mount.h>
71 #include <sys/disk.h>
72 #include <sys/fcntl.h>
73 #include <sys/filedesc.h>
74 #include <sys/filio.h>
75 #include <sys/proc.h>
76 #include <sys/pcpu.h>
77 #include <sys/module.h>
78 #include <sys/sdt.h>
79 #include <sys/devicestat.h>
80 #include <sys/sysctl.h>
81 #include <sys/nv.h>
82 #include <sys/dnv.h>
83 #include <sys/sx.h>
84 
85 #include <geom/geom.h>
86 
87 #include <cam/cam.h>
88 #include <cam/scsi/scsi_all.h>
89 #include <cam/scsi/scsi_da.h>
90 #include <cam/ctl/ctl_io.h>
91 #include <cam/ctl/ctl.h>
92 #include <cam/ctl/ctl_backend.h>
93 #include <cam/ctl/ctl_ioctl.h>
94 #include <cam/ctl/ctl_ha.h>
95 #include <cam/ctl/ctl_scsi_all.h>
96 #include <cam/ctl/ctl_private.h>
97 #include <cam/ctl/ctl_error.h>
98 
99 /*
100  * The idea here is that we'll allocate enough S/G space to hold a 1MB
101  * I/O.  If we get an I/O larger than that, we'll split it.
102  */
103 #define	CTLBLK_HALF_IO_SIZE	(512 * 1024)
104 #define	CTLBLK_MAX_IO_SIZE	(CTLBLK_HALF_IO_SIZE * 2)
105 #define	CTLBLK_MIN_SEG		(128 * 1024)
106 #define	CTLBLK_MAX_SEG		MIN(CTLBLK_HALF_IO_SIZE, maxphys)
107 #define	CTLBLK_HALF_SEGS	MAX(CTLBLK_HALF_IO_SIZE / CTLBLK_MIN_SEG, 1)
108 #define	CTLBLK_MAX_SEGS		(CTLBLK_HALF_SEGS * 2)
109 #define	CTLBLK_NUM_SEGS		(CTLBLK_MAX_IO_SIZE / CTLBLK_MAX_SEG)
110 
111 #ifdef CTLBLK_DEBUG
112 #define DPRINTF(fmt, args...) \
113     printf("cbb(%s:%d): " fmt, __FUNCTION__, __LINE__, ##args)
114 #else
115 #define DPRINTF(fmt, args...) do {} while(0)
116 #endif
117 
118 #define PRIV(io)	\
119     ((struct ctl_ptr_len_flags *)&(io)->io_hdr.ctl_private[CTL_PRIV_BACKEND])
120 #define ARGS(io)	\
121     ((struct ctl_lba_len_flags *)&(io)->io_hdr.ctl_private[CTL_PRIV_LBA_LEN])
122 
123 SDT_PROVIDER_DEFINE(cbb);
124 
125 typedef enum {
126 	CTL_BE_BLOCK_LUN_UNCONFIGURED	= 0x01,
127 	CTL_BE_BLOCK_LUN_WAITING	= 0x04,
128 } ctl_be_block_lun_flags;
129 
130 typedef enum {
131 	CTL_BE_BLOCK_NONE,
132 	CTL_BE_BLOCK_DEV,
133 	CTL_BE_BLOCK_FILE
134 } ctl_be_block_type;
135 
136 struct ctl_be_block_filedata {
137 	struct ucred *cred;
138 };
139 
140 union ctl_be_block_bedata {
141 	struct ctl_be_block_filedata file;
142 };
143 
144 struct ctl_be_block_io;
145 struct ctl_be_block_lun;
146 
147 typedef void (*cbb_dispatch_t)(struct ctl_be_block_lun *be_lun,
148 			       struct ctl_be_block_io *beio);
149 typedef uint64_t (*cbb_getattr_t)(struct ctl_be_block_lun *be_lun,
150 				  const char *attrname);
151 
152 /*
153  * Backend LUN structure.  There is a 1:1 mapping between a block device
154  * and a backend block LUN, and between a backend block LUN and a CTL LUN.
155  */
156 struct ctl_be_block_lun {
157 	struct ctl_be_lun cbe_lun;		/* Must be first element. */
158 	struct ctl_lun_create_params params;
159 	char *dev_path;
160 	ctl_be_block_type dev_type;
161 	struct vnode *vn;
162 	union ctl_be_block_bedata backend;
163 	cbb_dispatch_t dispatch;
164 	cbb_dispatch_t lun_flush;
165 	cbb_dispatch_t unmap;
166 	cbb_dispatch_t get_lba_status;
167 	cbb_getattr_t getattr;
168 	uint64_t size_blocks;
169 	uint64_t size_bytes;
170 	struct ctl_be_block_softc *softc;
171 	struct devstat *disk_stats;
172 	ctl_be_block_lun_flags flags;
173 	SLIST_ENTRY(ctl_be_block_lun) links;
174 	struct taskqueue *io_taskqueue;
175 	struct task io_task;
176 	int num_threads;
177 	STAILQ_HEAD(, ctl_io_hdr) input_queue;
178 	STAILQ_HEAD(, ctl_io_hdr) config_read_queue;
179 	STAILQ_HEAD(, ctl_io_hdr) config_write_queue;
180 	STAILQ_HEAD(, ctl_io_hdr) datamove_queue;
181 	struct mtx_padalign io_lock;
182 	struct mtx_padalign queue_lock;
183 };
184 
185 /*
186  * Overall softc structure for the block backend module.
187  */
188 struct ctl_be_block_softc {
189 	struct sx			 modify_lock;
190 	struct mtx			 lock;
191 	int				 num_luns;
192 	SLIST_HEAD(, ctl_be_block_lun)	 lun_list;
193 	uma_zone_t			 beio_zone;
194 	uma_zone_t			 bufmin_zone;
195 	uma_zone_t			 bufmax_zone;
196 };
197 
198 static struct ctl_be_block_softc backend_block_softc;
199 
200 /*
201  * Per-I/O information.
202  */
203 struct ctl_be_block_io {
204 	union ctl_io			*io;
205 	struct ctl_sg_entry		sg_segs[CTLBLK_MAX_SEGS];
206 	struct iovec			xiovecs[CTLBLK_MAX_SEGS];
207 	int				refcnt;
208 	int				bio_cmd;
209 	int				two_sglists;
210 	int				num_segs;
211 	int				num_bios_sent;
212 	int				num_bios_done;
213 	int				send_complete;
214 	int				first_error;
215 	uint64_t			first_error_offset;
216 	struct bintime			ds_t0;
217 	devstat_tag_type		ds_tag_type;
218 	devstat_trans_flags		ds_trans_type;
219 	uint64_t			io_len;
220 	uint64_t			io_offset;
221 	int				io_arg;
222 	struct ctl_be_block_softc	*softc;
223 	struct ctl_be_block_lun		*lun;
224 	void (*beio_cont)(struct ctl_be_block_io *beio); /* to continue processing */
225 };
226 
227 extern struct ctl_softc *control_softc;
228 
229 static int cbb_num_threads = 32;
230 SYSCTL_NODE(_kern_cam_ctl, OID_AUTO, block, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
231 	    "CAM Target Layer Block Backend");
232 SYSCTL_INT(_kern_cam_ctl_block, OID_AUTO, num_threads, CTLFLAG_RWTUN,
233            &cbb_num_threads, 0, "Number of threads per backing file");
234 
235 static struct ctl_be_block_io *ctl_alloc_beio(struct ctl_be_block_softc *softc);
236 static void ctl_free_beio(struct ctl_be_block_io *beio);
237 static void ctl_complete_beio(struct ctl_be_block_io *beio);
238 static int ctl_be_block_move_done(union ctl_io *io, bool samethr);
239 static void ctl_be_block_biodone(struct bio *bio);
240 static void ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
241 				    struct ctl_be_block_io *beio);
242 static void ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
243 				       struct ctl_be_block_io *beio);
244 static void ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
245 				  struct ctl_be_block_io *beio);
246 static uint64_t ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun,
247 					 const char *attrname);
248 static void ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
249 				   struct ctl_be_block_io *beio);
250 static void ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
251 				   struct ctl_be_block_io *beio);
252 static void ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
253 				      struct ctl_be_block_io *beio);
254 static uint64_t ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun,
255 					 const char *attrname);
256 static void ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
257 				    union ctl_io *io);
258 static void ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
259 				    union ctl_io *io);
260 static void ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
261 				  union ctl_io *io);
262 static void ctl_be_block_worker(void *context, int pending);
263 static int ctl_be_block_submit(union ctl_io *io);
264 static int ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
265 				   int flag, struct thread *td);
266 static int ctl_be_block_open_file(struct ctl_be_block_lun *be_lun,
267 				  struct ctl_lun_req *req);
268 static int ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun,
269 				 struct ctl_lun_req *req);
270 static int ctl_be_block_close(struct ctl_be_block_lun *be_lun);
271 static int ctl_be_block_open(struct ctl_be_block_lun *be_lun,
272 			     struct ctl_lun_req *req);
273 static int ctl_be_block_create(struct ctl_be_block_softc *softc,
274 			       struct ctl_lun_req *req);
275 static int ctl_be_block_rm(struct ctl_be_block_softc *softc,
276 			   struct ctl_lun_req *req);
277 static int ctl_be_block_modify(struct ctl_be_block_softc *softc,
278 			   struct ctl_lun_req *req);
279 static void ctl_be_block_lun_shutdown(struct ctl_be_lun *cbe_lun);
280 static int ctl_be_block_config_write(union ctl_io *io);
281 static int ctl_be_block_config_read(union ctl_io *io);
282 static int ctl_be_block_lun_info(struct ctl_be_lun *cbe_lun, struct sbuf *sb);
283 static uint64_t ctl_be_block_lun_attr(struct ctl_be_lun *cbe_lun, const char *attrname);
284 static int ctl_be_block_init(void);
285 static int ctl_be_block_shutdown(void);
286 
287 static struct ctl_backend_driver ctl_be_block_driver =
288 {
289 	.name = "block",
290 	.flags = CTL_BE_FLAG_HAS_CONFIG,
291 	.init = ctl_be_block_init,
292 	.shutdown = ctl_be_block_shutdown,
293 	.data_submit = ctl_be_block_submit,
294 	.config_read = ctl_be_block_config_read,
295 	.config_write = ctl_be_block_config_write,
296 	.ioctl = ctl_be_block_ioctl,
297 	.lun_info = ctl_be_block_lun_info,
298 	.lun_attr = ctl_be_block_lun_attr
299 };
300 
301 MALLOC_DEFINE(M_CTLBLK, "ctlblock", "Memory used for CTL block backend");
302 CTL_BACKEND_DECLARE(cbb, ctl_be_block_driver);
303 
304 static void
305 ctl_alloc_seg(struct ctl_be_block_softc *softc, struct ctl_sg_entry *sg,
306     size_t len)
307 {
308 
309 	if (len <= CTLBLK_MIN_SEG) {
310 		sg->addr = uma_zalloc(softc->bufmin_zone, M_WAITOK);
311 	} else {
312 		KASSERT(len <= CTLBLK_MAX_SEG,
313 		    ("Too large alloc %zu > %lu", len, CTLBLK_MAX_SEG));
314 		sg->addr = uma_zalloc(softc->bufmax_zone, M_WAITOK);
315 	}
316 	sg->len = len;
317 }
318 
319 static void
320 ctl_free_seg(struct ctl_be_block_softc *softc, struct ctl_sg_entry *sg)
321 {
322 
323 	if (sg->len <= CTLBLK_MIN_SEG) {
324 		uma_zfree(softc->bufmin_zone, sg->addr);
325 	} else {
326 		KASSERT(sg->len <= CTLBLK_MAX_SEG,
327 		    ("Too large free %zu > %lu", sg->len, CTLBLK_MAX_SEG));
328 		uma_zfree(softc->bufmax_zone, sg->addr);
329 	}
330 }
331 
332 static struct ctl_be_block_io *
333 ctl_alloc_beio(struct ctl_be_block_softc *softc)
334 {
335 	struct ctl_be_block_io *beio;
336 
337 	beio = uma_zalloc(softc->beio_zone, M_WAITOK | M_ZERO);
338 	beio->softc = softc;
339 	beio->refcnt = 1;
340 	return (beio);
341 }
342 
343 static void
344 ctl_real_free_beio(struct ctl_be_block_io *beio)
345 {
346 	struct ctl_be_block_softc *softc = beio->softc;
347 	int i;
348 
349 	for (i = 0; i < beio->num_segs; i++) {
350 		ctl_free_seg(softc, &beio->sg_segs[i]);
351 
352 		/* For compare we had two equal S/G lists. */
353 		if (beio->two_sglists) {
354 			ctl_free_seg(softc,
355 			    &beio->sg_segs[i + CTLBLK_HALF_SEGS]);
356 		}
357 	}
358 
359 	uma_zfree(softc->beio_zone, beio);
360 }
361 
362 static void
363 ctl_refcnt_beio(void *arg, int diff)
364 {
365 	struct ctl_be_block_io *beio = arg;
366 
367 	if (atomic_fetchadd_int(&beio->refcnt, diff) + diff == 0)
368 		ctl_real_free_beio(beio);
369 }
370 
371 static void
372 ctl_free_beio(struct ctl_be_block_io *beio)
373 {
374 
375 	ctl_refcnt_beio(beio, -1);
376 }
377 
378 static void
379 ctl_complete_beio(struct ctl_be_block_io *beio)
380 {
381 	union ctl_io *io = beio->io;
382 
383 	if (beio->beio_cont != NULL) {
384 		beio->beio_cont(beio);
385 	} else {
386 		ctl_free_beio(beio);
387 		ctl_data_submit_done(io);
388 	}
389 }
390 
391 static size_t
392 cmp(uint8_t *a, uint8_t *b, size_t size)
393 {
394 	size_t i;
395 
396 	for (i = 0; i < size; i++) {
397 		if (a[i] != b[i])
398 			break;
399 	}
400 	return (i);
401 }
402 
403 static void
404 ctl_be_block_compare(union ctl_io *io)
405 {
406 	struct ctl_be_block_io *beio;
407 	uint64_t off, res;
408 	int i;
409 	uint8_t info[8];
410 
411 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
412 	off = 0;
413 	for (i = 0; i < beio->num_segs; i++) {
414 		res = cmp(beio->sg_segs[i].addr,
415 		    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr,
416 		    beio->sg_segs[i].len);
417 		off += res;
418 		if (res < beio->sg_segs[i].len)
419 			break;
420 	}
421 	if (i < beio->num_segs) {
422 		scsi_u64to8b(off, info);
423 		ctl_set_sense(&io->scsiio, /*current_error*/ 1,
424 		    /*sense_key*/ SSD_KEY_MISCOMPARE,
425 		    /*asc*/ 0x1D, /*ascq*/ 0x00,
426 		    /*type*/ SSD_ELEM_INFO,
427 		    /*size*/ sizeof(info), /*data*/ &info,
428 		    /*type*/ SSD_ELEM_NONE);
429 	} else
430 		ctl_set_success(&io->scsiio);
431 }
432 
433 static int
434 ctl_be_block_move_done(union ctl_io *io, bool samethr)
435 {
436 	struct ctl_be_block_io *beio;
437 	struct ctl_be_block_lun *be_lun;
438 	struct ctl_lba_len_flags *lbalen;
439 
440 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
441 
442 	DPRINTF("entered\n");
443 	io->scsiio.kern_rel_offset += io->scsiio.kern_data_len;
444 
445 	/*
446 	 * We set status at this point for read and compare commands.
447 	 */
448 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) == 0 &&
449 	    (io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE) {
450 		lbalen = ARGS(io);
451 		if (lbalen->flags & CTL_LLF_READ) {
452 			ctl_set_success(&io->scsiio);
453 		} else if (lbalen->flags & CTL_LLF_COMPARE) {
454 			/* We have two data blocks ready for comparison. */
455 			ctl_be_block_compare(io);
456 		}
457 	}
458 
459 	/*
460 	 * If this is a read, or a write with errors, it is done.
461 	 */
462 	if ((beio->bio_cmd == BIO_READ)
463 	 || ((io->io_hdr.flags & CTL_FLAG_ABORT) != 0)
464 	 || ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE)) {
465 		ctl_complete_beio(beio);
466 		return (0);
467 	}
468 
469 	/*
470 	 * At this point, we have a write and the DMA completed successfully.
471 	 * If we were called synchronously in the original thread then just
472 	 * dispatch, otherwise we now have to queue it to the task queue to
473 	 * execute the backend I/O.  That is because we do blocking
474 	 * memory allocations, and in the file backing case, blocking I/O.
475 	 * This move done routine is generally called in the SIM's
476 	 * interrupt context, and therefore we cannot block.
477 	 */
478 	be_lun = (struct ctl_be_block_lun *)CTL_BACKEND_LUN(io);
479 	if (samethr) {
480 		be_lun->dispatch(be_lun, beio);
481 	} else {
482 		mtx_lock(&be_lun->queue_lock);
483 		STAILQ_INSERT_TAIL(&be_lun->datamove_queue, &io->io_hdr, links);
484 		mtx_unlock(&be_lun->queue_lock);
485 		taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
486 	}
487 	return (0);
488 }
489 
490 static void
491 ctl_be_block_biodone(struct bio *bio)
492 {
493 	struct ctl_be_block_io *beio = bio->bio_caller1;
494 	struct ctl_be_block_lun *be_lun = beio->lun;
495 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
496 	union ctl_io *io;
497 	int error;
498 
499 	io = beio->io;
500 
501 	DPRINTF("entered\n");
502 
503 	error = bio->bio_error;
504 	mtx_lock(&be_lun->io_lock);
505 	if (error != 0 &&
506 	    (beio->first_error == 0 ||
507 	     bio->bio_offset < beio->first_error_offset)) {
508 		beio->first_error = error;
509 		beio->first_error_offset = bio->bio_offset;
510 	}
511 
512 	beio->num_bios_done++;
513 
514 	/*
515 	 * XXX KDM will this cause WITNESS to complain?  Holding a lock
516 	 * during the free might cause it to complain.
517 	 */
518 	g_destroy_bio(bio);
519 
520 	/*
521 	 * If the send complete bit isn't set, or we aren't the last I/O to
522 	 * complete, then we're done.
523 	 */
524 	if ((beio->send_complete == 0)
525 	 || (beio->num_bios_done < beio->num_bios_sent)) {
526 		mtx_unlock(&be_lun->io_lock);
527 		return;
528 	}
529 
530 	/*
531 	 * At this point, we've verified that we are the last I/O to
532 	 * complete, so it's safe to drop the lock.
533 	 */
534 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
535 	    beio->ds_tag_type, beio->ds_trans_type,
536 	    /*now*/ NULL, /*then*/&beio->ds_t0);
537 	mtx_unlock(&be_lun->io_lock);
538 
539 	/*
540 	 * If there are any errors from the backing device, we fail the
541 	 * entire I/O with a medium error.
542 	 */
543 	error = beio->first_error;
544 	if (error != 0) {
545 		if (error == EOPNOTSUPP) {
546 			ctl_set_invalid_opcode(&io->scsiio);
547 		} else if (error == ENOSPC || error == EDQUOT) {
548 			ctl_set_space_alloc_fail(&io->scsiio);
549 		} else if (error == EROFS || error == EACCES) {
550 			ctl_set_hw_write_protected(&io->scsiio);
551 		} else if (beio->bio_cmd == BIO_FLUSH) {
552 			/* XXX KDM is there is a better error here? */
553 			ctl_set_internal_failure(&io->scsiio,
554 						 /*sks_valid*/ 1,
555 						 /*retry_count*/ 0xbad2);
556 		} else {
557 			ctl_set_medium_error(&io->scsiio,
558 			    beio->bio_cmd == BIO_READ);
559 		}
560 		ctl_complete_beio(beio);
561 		return;
562 	}
563 
564 	/*
565 	 * If this is a write, a flush, a delete or verify, we're all done.
566 	 * If this is a read, we can now send the data to the user.
567 	 */
568 	if ((beio->bio_cmd == BIO_WRITE)
569 	 || (beio->bio_cmd == BIO_FLUSH)
570 	 || (beio->bio_cmd == BIO_DELETE)
571 	 || (ARGS(io)->flags & CTL_LLF_VERIFY)) {
572 		ctl_set_success(&io->scsiio);
573 		ctl_complete_beio(beio);
574 	} else {
575 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
576 		    beio->beio_cont == NULL) {
577 			ctl_set_success(&io->scsiio);
578 			if (cbe_lun->serseq >= CTL_LUN_SERSEQ_SOFT)
579 				ctl_serseq_done(io);
580 		}
581 		ctl_datamove(io);
582 	}
583 }
584 
585 static void
586 ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
587 			struct ctl_be_block_io *beio)
588 {
589 	union ctl_io *io = beio->io;
590 	struct mount *mountpoint;
591 	int error, lock_flags;
592 
593 	DPRINTF("entered\n");
594 
595 	binuptime(&beio->ds_t0);
596 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
597 
598 	(void) vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
599 
600 	if (MNT_SHARED_WRITES(mountpoint) ||
601 	    ((mountpoint == NULL) && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
602 		lock_flags = LK_SHARED;
603 	else
604 		lock_flags = LK_EXCLUSIVE;
605 	vn_lock(be_lun->vn, lock_flags | LK_RETRY);
606 	error = VOP_FSYNC(be_lun->vn, beio->io_arg ? MNT_NOWAIT : MNT_WAIT,
607 	    curthread);
608 	VOP_UNLOCK(be_lun->vn);
609 
610 	vn_finished_write(mountpoint);
611 
612 	mtx_lock(&be_lun->io_lock);
613 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
614 	    beio->ds_tag_type, beio->ds_trans_type,
615 	    /*now*/ NULL, /*then*/&beio->ds_t0);
616 	mtx_unlock(&be_lun->io_lock);
617 
618 	if (error == 0)
619 		ctl_set_success(&io->scsiio);
620 	else {
621 		/* XXX KDM is there is a better error here? */
622 		ctl_set_internal_failure(&io->scsiio,
623 					 /*sks_valid*/ 1,
624 					 /*retry_count*/ 0xbad1);
625 	}
626 
627 	ctl_complete_beio(beio);
628 }
629 
630 SDT_PROBE_DEFINE1(cbb, , read, file_start, "uint64_t");
631 SDT_PROBE_DEFINE1(cbb, , write, file_start, "uint64_t");
632 SDT_PROBE_DEFINE1(cbb, , read, file_done,"uint64_t");
633 SDT_PROBE_DEFINE1(cbb, , write, file_done, "uint64_t");
634 
635 static void
636 ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
637 			   struct ctl_be_block_io *beio)
638 {
639 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
640 	struct ctl_be_block_filedata *file_data;
641 	union ctl_io *io;
642 	struct uio xuio;
643 	struct iovec *xiovec;
644 	size_t s;
645 	int error, flags, i;
646 
647 	DPRINTF("entered\n");
648 
649 	file_data = &be_lun->backend.file;
650 	io = beio->io;
651 	flags = 0;
652 	if (ARGS(io)->flags & CTL_LLF_DPO)
653 		flags |= IO_DIRECT;
654 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
655 		flags |= IO_SYNC;
656 
657 	bzero(&xuio, sizeof(xuio));
658 	if (beio->bio_cmd == BIO_READ) {
659 		SDT_PROBE0(cbb, , read, file_start);
660 		xuio.uio_rw = UIO_READ;
661 	} else {
662 		SDT_PROBE0(cbb, , write, file_start);
663 		xuio.uio_rw = UIO_WRITE;
664 	}
665 	xuio.uio_offset = beio->io_offset;
666 	xuio.uio_resid = beio->io_len;
667 	xuio.uio_segflg = UIO_SYSSPACE;
668 	xuio.uio_iov = beio->xiovecs;
669 	xuio.uio_iovcnt = beio->num_segs;
670 	xuio.uio_td = curthread;
671 
672 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
673 		xiovec->iov_base = beio->sg_segs[i].addr;
674 		xiovec->iov_len = beio->sg_segs[i].len;
675 	}
676 
677 	binuptime(&beio->ds_t0);
678 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
679 
680 	if (beio->bio_cmd == BIO_READ) {
681 		vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
682 
683 		if (beio->beio_cont == NULL &&
684 		    cbe_lun->serseq == CTL_LUN_SERSEQ_SOFT)
685 			ctl_serseq_done(io);
686 		/*
687 		 * UFS pays attention to IO_DIRECT for reads.  If the
688 		 * DIRECTIO option is configured into the kernel, it calls
689 		 * ffs_rawread().  But that only works for single-segment
690 		 * uios with user space addresses.  In our case, with a
691 		 * kernel uio, it still reads into the buffer cache, but it
692 		 * will just try to release the buffer from the cache later
693 		 * on in ffs_read().
694 		 *
695 		 * ZFS does not pay attention to IO_DIRECT for reads.
696 		 *
697 		 * UFS does not pay attention to IO_SYNC for reads.
698 		 *
699 		 * ZFS pays attention to IO_SYNC (which translates into the
700 		 * Solaris define FRSYNC for zfs_read()) for reads.  It
701 		 * attempts to sync the file before reading.
702 		 */
703 		error = VOP_READ(be_lun->vn, &xuio, flags, file_data->cred);
704 
705 		VOP_UNLOCK(be_lun->vn);
706 		SDT_PROBE0(cbb, , read, file_done);
707 		if (error == 0 && xuio.uio_resid > 0) {
708 			/*
709 			 * If we red less then requested (EOF), then
710 			 * we should clean the rest of the buffer.
711 			 */
712 			s = beio->io_len - xuio.uio_resid;
713 			for (i = 0; i < beio->num_segs; i++) {
714 				if (s >= beio->sg_segs[i].len) {
715 					s -= beio->sg_segs[i].len;
716 					continue;
717 				}
718 				bzero((uint8_t *)beio->sg_segs[i].addr + s,
719 				    beio->sg_segs[i].len - s);
720 				s = 0;
721 			}
722 		}
723 	} else {
724 		struct mount *mountpoint;
725 		int lock_flags;
726 
727 		(void)vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
728 
729 		if (MNT_SHARED_WRITES(mountpoint) || ((mountpoint == NULL)
730 		  && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
731 			lock_flags = LK_SHARED;
732 		else
733 			lock_flags = LK_EXCLUSIVE;
734 		vn_lock(be_lun->vn, lock_flags | LK_RETRY);
735 
736 		/*
737 		 * UFS pays attention to IO_DIRECT for writes.  The write
738 		 * is done asynchronously.  (Normally the write would just
739 		 * get put into cache.
740 		 *
741 		 * UFS pays attention to IO_SYNC for writes.  It will
742 		 * attempt to write the buffer out synchronously if that
743 		 * flag is set.
744 		 *
745 		 * ZFS does not pay attention to IO_DIRECT for writes.
746 		 *
747 		 * ZFS pays attention to IO_SYNC (a.k.a. FSYNC or FRSYNC)
748 		 * for writes.  It will flush the transaction from the
749 		 * cache before returning.
750 		 */
751 		error = VOP_WRITE(be_lun->vn, &xuio, flags, file_data->cred);
752 		VOP_UNLOCK(be_lun->vn);
753 
754 		vn_finished_write(mountpoint);
755 		SDT_PROBE0(cbb, , write, file_done);
756         }
757 
758 	mtx_lock(&be_lun->io_lock);
759 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
760 	    beio->ds_tag_type, beio->ds_trans_type,
761 	    /*now*/ NULL, /*then*/&beio->ds_t0);
762 	mtx_unlock(&be_lun->io_lock);
763 
764 	/*
765 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
766 	 * return the I/O to the user.
767 	 */
768 	if (error != 0) {
769 		if (error == ENOSPC || error == EDQUOT) {
770 			ctl_set_space_alloc_fail(&io->scsiio);
771 		} else if (error == EROFS || error == EACCES) {
772 			ctl_set_hw_write_protected(&io->scsiio);
773 		} else {
774 			ctl_set_medium_error(&io->scsiio,
775 			    beio->bio_cmd == BIO_READ);
776 		}
777 		ctl_complete_beio(beio);
778 		return;
779 	}
780 
781 	/*
782 	 * If this is a write or a verify, we're all done.
783 	 * If this is a read, we can now send the data to the user.
784 	 */
785 	if ((beio->bio_cmd == BIO_WRITE) ||
786 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
787 		ctl_set_success(&io->scsiio);
788 		ctl_complete_beio(beio);
789 	} else {
790 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
791 		    beio->beio_cont == NULL) {
792 			ctl_set_success(&io->scsiio);
793 			if (cbe_lun->serseq > CTL_LUN_SERSEQ_SOFT)
794 				ctl_serseq_done(io);
795 		}
796 		ctl_datamove(io);
797 	}
798 }
799 
800 static void
801 ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
802 			struct ctl_be_block_io *beio)
803 {
804 	union ctl_io *io = beio->io;
805 	struct ctl_lba_len_flags *lbalen = ARGS(io);
806 	struct scsi_get_lba_status_data *data;
807 	off_t roff, off;
808 	int error, status;
809 
810 	DPRINTF("entered\n");
811 
812 	off = roff = ((off_t)lbalen->lba) * be_lun->cbe_lun.blocksize;
813 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
814 	error = VOP_IOCTL(be_lun->vn, FIOSEEKHOLE, &off,
815 	    0, curthread->td_ucred, curthread);
816 	if (error == 0 && off > roff)
817 		status = 0;	/* mapped up to off */
818 	else {
819 		error = VOP_IOCTL(be_lun->vn, FIOSEEKDATA, &off,
820 		    0, curthread->td_ucred, curthread);
821 		if (error == 0 && off > roff)
822 			status = 1;	/* deallocated up to off */
823 		else {
824 			status = 0;	/* unknown up to the end */
825 			off = be_lun->size_bytes;
826 		}
827 	}
828 	VOP_UNLOCK(be_lun->vn);
829 
830 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
831 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
832 	scsi_ulto4b(MIN(UINT32_MAX, off / be_lun->cbe_lun.blocksize -
833 	    lbalen->lba), data->descr[0].length);
834 	data->descr[0].status = status;
835 
836 	ctl_complete_beio(beio);
837 }
838 
839 static uint64_t
840 ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun, const char *attrname)
841 {
842 	struct vattr		vattr;
843 	struct statfs		statfs;
844 	uint64_t		val;
845 	int			error;
846 
847 	val = UINT64_MAX;
848 	if (be_lun->vn == NULL)
849 		return (val);
850 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
851 	if (strcmp(attrname, "blocksused") == 0) {
852 		error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
853 		if (error == 0)
854 			val = vattr.va_bytes / be_lun->cbe_lun.blocksize;
855 	}
856 	if (strcmp(attrname, "blocksavail") == 0 &&
857 	    !VN_IS_DOOMED(be_lun->vn)) {
858 		error = VFS_STATFS(be_lun->vn->v_mount, &statfs);
859 		if (error == 0)
860 			val = statfs.f_bavail * statfs.f_bsize /
861 			    be_lun->cbe_lun.blocksize;
862 	}
863 	VOP_UNLOCK(be_lun->vn);
864 	return (val);
865 }
866 
867 static void
868 ctl_be_block_dispatch_zvol(struct ctl_be_block_lun *be_lun,
869 			   struct ctl_be_block_io *beio)
870 {
871 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
872 	union ctl_io *io;
873 	struct cdevsw *csw;
874 	struct cdev *dev;
875 	struct uio xuio;
876 	struct iovec *xiovec;
877 	int error, flags, i, ref;
878 
879 	DPRINTF("entered\n");
880 
881 	io = beio->io;
882 	flags = 0;
883 	if (ARGS(io)->flags & CTL_LLF_DPO)
884 		flags |= IO_DIRECT;
885 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
886 		flags |= IO_SYNC;
887 
888 	bzero(&xuio, sizeof(xuio));
889 	if (beio->bio_cmd == BIO_READ) {
890 		SDT_PROBE0(cbb, , read, file_start);
891 		xuio.uio_rw = UIO_READ;
892 	} else {
893 		SDT_PROBE0(cbb, , write, file_start);
894 		xuio.uio_rw = UIO_WRITE;
895 	}
896 	xuio.uio_offset = beio->io_offset;
897 	xuio.uio_resid = beio->io_len;
898 	xuio.uio_segflg = UIO_SYSSPACE;
899 	xuio.uio_iov = beio->xiovecs;
900 	xuio.uio_iovcnt = beio->num_segs;
901 	xuio.uio_td = curthread;
902 
903 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
904 		xiovec->iov_base = beio->sg_segs[i].addr;
905 		xiovec->iov_len = beio->sg_segs[i].len;
906 	}
907 
908 	binuptime(&beio->ds_t0);
909 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
910 
911 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
912 	if (csw) {
913 		if (beio->bio_cmd == BIO_READ) {
914 			if (beio->beio_cont == NULL &&
915 			    cbe_lun->serseq == CTL_LUN_SERSEQ_SOFT)
916 				ctl_serseq_done(io);
917 			error = csw->d_read(dev, &xuio, flags);
918 		} else
919 			error = csw->d_write(dev, &xuio, flags);
920 		dev_relthread(dev, ref);
921 	} else
922 		error = ENXIO;
923 
924 	if (beio->bio_cmd == BIO_READ)
925 		SDT_PROBE0(cbb, , read, file_done);
926 	else
927 		SDT_PROBE0(cbb, , write, file_done);
928 
929 	mtx_lock(&be_lun->io_lock);
930 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
931 	    beio->ds_tag_type, beio->ds_trans_type,
932 	    /*now*/ NULL, /*then*/&beio->ds_t0);
933 	mtx_unlock(&be_lun->io_lock);
934 
935 	/*
936 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
937 	 * return the I/O to the user.
938 	 */
939 	if (error != 0) {
940 		if (error == ENOSPC || error == EDQUOT) {
941 			ctl_set_space_alloc_fail(&io->scsiio);
942 		} else if (error == EROFS || error == EACCES) {
943 			ctl_set_hw_write_protected(&io->scsiio);
944 		} else {
945 			ctl_set_medium_error(&io->scsiio,
946 			    beio->bio_cmd == BIO_READ);
947 		}
948 		ctl_complete_beio(beio);
949 		return;
950 	}
951 
952 	/*
953 	 * If this is a write or a verify, we're all done.
954 	 * If this is a read, we can now send the data to the user.
955 	 */
956 	if ((beio->bio_cmd == BIO_WRITE) ||
957 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
958 		ctl_set_success(&io->scsiio);
959 		ctl_complete_beio(beio);
960 	} else {
961 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
962 		    beio->beio_cont == NULL) {
963 			ctl_set_success(&io->scsiio);
964 			if (cbe_lun->serseq > CTL_LUN_SERSEQ_SOFT)
965 				ctl_serseq_done(io);
966 		}
967 		ctl_datamove(io);
968 	}
969 }
970 
971 static void
972 ctl_be_block_gls_zvol(struct ctl_be_block_lun *be_lun,
973 			struct ctl_be_block_io *beio)
974 {
975 	union ctl_io *io = beio->io;
976 	struct cdevsw *csw;
977 	struct cdev *dev;
978 	struct ctl_lba_len_flags *lbalen = ARGS(io);
979 	struct scsi_get_lba_status_data *data;
980 	off_t roff, off;
981 	int error, ref, status;
982 
983 	DPRINTF("entered\n");
984 
985 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
986 	if (csw == NULL) {
987 		status = 0;	/* unknown up to the end */
988 		off = be_lun->size_bytes;
989 		goto done;
990 	}
991 	off = roff = ((off_t)lbalen->lba) * be_lun->cbe_lun.blocksize;
992 	error = csw->d_ioctl(dev, FIOSEEKHOLE, (caddr_t)&off, FREAD,
993 	    curthread);
994 	if (error == 0 && off > roff)
995 		status = 0;	/* mapped up to off */
996 	else {
997 		error = csw->d_ioctl(dev, FIOSEEKDATA, (caddr_t)&off, FREAD,
998 		    curthread);
999 		if (error == 0 && off > roff)
1000 			status = 1;	/* deallocated up to off */
1001 		else {
1002 			status = 0;	/* unknown up to the end */
1003 			off = be_lun->size_bytes;
1004 		}
1005 	}
1006 	dev_relthread(dev, ref);
1007 
1008 done:
1009 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
1010 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
1011 	scsi_ulto4b(MIN(UINT32_MAX, off / be_lun->cbe_lun.blocksize -
1012 	    lbalen->lba), data->descr[0].length);
1013 	data->descr[0].status = status;
1014 
1015 	ctl_complete_beio(beio);
1016 }
1017 
1018 static void
1019 ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
1020 		       struct ctl_be_block_io *beio)
1021 {
1022 	struct bio *bio;
1023 	struct cdevsw *csw;
1024 	struct cdev *dev;
1025 	int ref;
1026 
1027 	DPRINTF("entered\n");
1028 
1029 	/* This can't fail, it's a blocking allocation. */
1030 	bio = g_alloc_bio();
1031 
1032 	bio->bio_cmd	    = BIO_FLUSH;
1033 	bio->bio_offset	    = 0;
1034 	bio->bio_data	    = 0;
1035 	bio->bio_done	    = ctl_be_block_biodone;
1036 	bio->bio_caller1    = beio;
1037 	bio->bio_pblkno	    = 0;
1038 
1039 	/*
1040 	 * We don't need to acquire the LUN lock here, because we are only
1041 	 * sending one bio, and so there is no other context to synchronize
1042 	 * with.
1043 	 */
1044 	beio->num_bios_sent = 1;
1045 	beio->send_complete = 1;
1046 
1047 	binuptime(&beio->ds_t0);
1048 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1049 
1050 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1051 	if (csw) {
1052 		bio->bio_dev = dev;
1053 		csw->d_strategy(bio);
1054 		dev_relthread(dev, ref);
1055 	} else {
1056 		bio->bio_error = ENXIO;
1057 		ctl_be_block_biodone(bio);
1058 	}
1059 }
1060 
1061 static void
1062 ctl_be_block_unmap_dev_range(struct ctl_be_block_lun *be_lun,
1063 		       struct ctl_be_block_io *beio,
1064 		       uint64_t off, uint64_t len, int last)
1065 {
1066 	struct bio *bio;
1067 	uint64_t maxlen;
1068 	struct cdevsw *csw;
1069 	struct cdev *dev;
1070 	int ref;
1071 
1072 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1073 	maxlen = LONG_MAX - (LONG_MAX % be_lun->cbe_lun.blocksize);
1074 	while (len > 0) {
1075 		bio = g_alloc_bio();
1076 		bio->bio_cmd	    = BIO_DELETE;
1077 		bio->bio_dev	    = dev;
1078 		bio->bio_offset	    = off;
1079 		bio->bio_length	    = MIN(len, maxlen);
1080 		bio->bio_data	    = 0;
1081 		bio->bio_done	    = ctl_be_block_biodone;
1082 		bio->bio_caller1    = beio;
1083 		bio->bio_pblkno     = off / be_lun->cbe_lun.blocksize;
1084 
1085 		off += bio->bio_length;
1086 		len -= bio->bio_length;
1087 
1088 		mtx_lock(&be_lun->io_lock);
1089 		beio->num_bios_sent++;
1090 		if (last && len == 0)
1091 			beio->send_complete = 1;
1092 		mtx_unlock(&be_lun->io_lock);
1093 
1094 		if (csw) {
1095 			csw->d_strategy(bio);
1096 		} else {
1097 			bio->bio_error = ENXIO;
1098 			ctl_be_block_biodone(bio);
1099 		}
1100 	}
1101 	if (csw)
1102 		dev_relthread(dev, ref);
1103 }
1104 
1105 static void
1106 ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
1107 		       struct ctl_be_block_io *beio)
1108 {
1109 	union ctl_io *io;
1110 	struct ctl_ptr_len_flags *ptrlen;
1111 	struct scsi_unmap_desc *buf, *end;
1112 	uint64_t len;
1113 
1114 	io = beio->io;
1115 
1116 	DPRINTF("entered\n");
1117 
1118 	binuptime(&beio->ds_t0);
1119 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1120 
1121 	if (beio->io_offset == -1) {
1122 		beio->io_len = 0;
1123 		ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1124 		buf = (struct scsi_unmap_desc *)ptrlen->ptr;
1125 		end = buf + ptrlen->len / sizeof(*buf);
1126 		for (; buf < end; buf++) {
1127 			len = (uint64_t)scsi_4btoul(buf->length) *
1128 			    be_lun->cbe_lun.blocksize;
1129 			beio->io_len += len;
1130 			ctl_be_block_unmap_dev_range(be_lun, beio,
1131 			    scsi_8btou64(buf->lba) * be_lun->cbe_lun.blocksize,
1132 			    len, (end - buf < 2) ? TRUE : FALSE);
1133 		}
1134 	} else
1135 		ctl_be_block_unmap_dev_range(be_lun, beio,
1136 		    beio->io_offset, beio->io_len, TRUE);
1137 }
1138 
1139 static void
1140 ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
1141 			  struct ctl_be_block_io *beio)
1142 {
1143 	TAILQ_HEAD(, bio) queue = TAILQ_HEAD_INITIALIZER(queue);
1144 	struct bio *bio;
1145 	struct cdevsw *csw;
1146 	struct cdev *dev;
1147 	off_t cur_offset;
1148 	int i, max_iosize, ref;
1149 
1150 	DPRINTF("entered\n");
1151 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1152 
1153 	/*
1154 	 * We have to limit our I/O size to the maximum supported by the
1155 	 * backend device.
1156 	 */
1157 	if (csw) {
1158 		max_iosize = dev->si_iosize_max;
1159 		if (max_iosize < PAGE_SIZE)
1160 			max_iosize = DFLTPHYS;
1161 	} else
1162 		max_iosize = DFLTPHYS;
1163 
1164 	cur_offset = beio->io_offset;
1165 	for (i = 0; i < beio->num_segs; i++) {
1166 		size_t cur_size;
1167 		uint8_t *cur_ptr;
1168 
1169 		cur_size = beio->sg_segs[i].len;
1170 		cur_ptr = beio->sg_segs[i].addr;
1171 
1172 		while (cur_size > 0) {
1173 			/* This can't fail, it's a blocking allocation. */
1174 			bio = g_alloc_bio();
1175 
1176 			KASSERT(bio != NULL, ("g_alloc_bio() failed!\n"));
1177 
1178 			bio->bio_cmd = beio->bio_cmd;
1179 			bio->bio_dev = dev;
1180 			bio->bio_caller1 = beio;
1181 			bio->bio_length = min(cur_size, max_iosize);
1182 			bio->bio_offset = cur_offset;
1183 			bio->bio_data = cur_ptr;
1184 			bio->bio_done = ctl_be_block_biodone;
1185 			bio->bio_pblkno = cur_offset / be_lun->cbe_lun.blocksize;
1186 
1187 			cur_offset += bio->bio_length;
1188 			cur_ptr += bio->bio_length;
1189 			cur_size -= bio->bio_length;
1190 
1191 			TAILQ_INSERT_TAIL(&queue, bio, bio_queue);
1192 			beio->num_bios_sent++;
1193 		}
1194 	}
1195 	beio->send_complete = 1;
1196 	binuptime(&beio->ds_t0);
1197 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1198 
1199 	/*
1200 	 * Fire off all allocated requests!
1201 	 */
1202 	while ((bio = TAILQ_FIRST(&queue)) != NULL) {
1203 		TAILQ_REMOVE(&queue, bio, bio_queue);
1204 		if (csw)
1205 			csw->d_strategy(bio);
1206 		else {
1207 			bio->bio_error = ENXIO;
1208 			ctl_be_block_biodone(bio);
1209 		}
1210 	}
1211 	if (csw)
1212 		dev_relthread(dev, ref);
1213 }
1214 
1215 static uint64_t
1216 ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun, const char *attrname)
1217 {
1218 	struct diocgattr_arg	arg;
1219 	struct cdevsw *csw;
1220 	struct cdev *dev;
1221 	int error, ref;
1222 
1223 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1224 	if (csw == NULL)
1225 		return (UINT64_MAX);
1226 	strlcpy(arg.name, attrname, sizeof(arg.name));
1227 	arg.len = sizeof(arg.value.off);
1228 	if (csw->d_ioctl) {
1229 		error = csw->d_ioctl(dev, DIOCGATTR, (caddr_t)&arg, FREAD,
1230 		    curthread);
1231 	} else
1232 		error = ENODEV;
1233 	dev_relthread(dev, ref);
1234 	if (error != 0)
1235 		return (UINT64_MAX);
1236 	return (arg.value.off);
1237 }
1238 
1239 static void
1240 ctl_be_block_cw_dispatch_sync(struct ctl_be_block_lun *be_lun,
1241 			    union ctl_io *io)
1242 {
1243 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1244 	struct ctl_be_block_io *beio;
1245 	struct ctl_lba_len_flags *lbalen;
1246 
1247 	DPRINTF("entered\n");
1248 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1249 	lbalen = (struct ctl_lba_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1250 
1251 	beio->io_len = lbalen->len * cbe_lun->blocksize;
1252 	beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1253 	beio->io_arg = (lbalen->flags & SSC_IMMED) != 0;
1254 	beio->bio_cmd = BIO_FLUSH;
1255 	beio->ds_trans_type = DEVSTAT_NO_DATA;
1256 	DPRINTF("SYNC\n");
1257 	be_lun->lun_flush(be_lun, beio);
1258 }
1259 
1260 static void
1261 ctl_be_block_cw_done_ws(struct ctl_be_block_io *beio)
1262 {
1263 	union ctl_io *io;
1264 
1265 	io = beio->io;
1266 	ctl_free_beio(beio);
1267 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1268 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1269 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1270 		ctl_config_write_done(io);
1271 		return;
1272 	}
1273 
1274 	ctl_be_block_config_write(io);
1275 }
1276 
1277 static void
1278 ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
1279 			    union ctl_io *io)
1280 {
1281 	struct ctl_be_block_softc *softc = be_lun->softc;
1282 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1283 	struct ctl_be_block_io *beio;
1284 	struct ctl_lba_len_flags *lbalen;
1285 	uint64_t len_left, lba;
1286 	uint32_t pb, pbo, adj;
1287 	int i, seglen;
1288 	uint8_t *buf, *end;
1289 
1290 	DPRINTF("entered\n");
1291 
1292 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1293 	lbalen = ARGS(io);
1294 
1295 	if (lbalen->flags & ~(SWS_LBDATA | SWS_UNMAP | SWS_ANCHOR | SWS_NDOB) ||
1296 	    (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR) && be_lun->unmap == NULL)) {
1297 		ctl_free_beio(beio);
1298 		ctl_set_invalid_field(&io->scsiio,
1299 				      /*sks_valid*/ 1,
1300 				      /*command*/ 1,
1301 				      /*field*/ 1,
1302 				      /*bit_valid*/ 0,
1303 				      /*bit*/ 0);
1304 		ctl_config_write_done(io);
1305 		return;
1306 	}
1307 
1308 	if (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR)) {
1309 		beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1310 		beio->io_len = (uint64_t)lbalen->len * cbe_lun->blocksize;
1311 		beio->bio_cmd = BIO_DELETE;
1312 		beio->ds_trans_type = DEVSTAT_FREE;
1313 
1314 		be_lun->unmap(be_lun, beio);
1315 		return;
1316 	}
1317 
1318 	beio->bio_cmd = BIO_WRITE;
1319 	beio->ds_trans_type = DEVSTAT_WRITE;
1320 
1321 	DPRINTF("WRITE SAME at LBA %jx len %u\n",
1322 	       (uintmax_t)lbalen->lba, lbalen->len);
1323 
1324 	pb = cbe_lun->blocksize << be_lun->cbe_lun.pblockexp;
1325 	if (be_lun->cbe_lun.pblockoff > 0)
1326 		pbo = pb - cbe_lun->blocksize * be_lun->cbe_lun.pblockoff;
1327 	else
1328 		pbo = 0;
1329 	len_left = (uint64_t)lbalen->len * cbe_lun->blocksize;
1330 	for (i = 0, lba = 0; i < CTLBLK_NUM_SEGS && len_left > 0; i++) {
1331 		/*
1332 		 * Setup the S/G entry for this chunk.
1333 		 */
1334 		seglen = MIN(CTLBLK_MAX_SEG, len_left);
1335 		if (pb > cbe_lun->blocksize) {
1336 			adj = ((lbalen->lba + lba) * cbe_lun->blocksize +
1337 			    seglen - pbo) % pb;
1338 			if (seglen > adj)
1339 				seglen -= adj;
1340 			else
1341 				seglen -= seglen % cbe_lun->blocksize;
1342 		} else
1343 			seglen -= seglen % cbe_lun->blocksize;
1344 		ctl_alloc_seg(softc, &beio->sg_segs[i], seglen);
1345 
1346 		DPRINTF("segment %d addr %p len %zd\n", i,
1347 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1348 
1349 		beio->num_segs++;
1350 		len_left -= seglen;
1351 
1352 		buf = beio->sg_segs[i].addr;
1353 		end = buf + seglen;
1354 		for (; buf < end; buf += cbe_lun->blocksize) {
1355 			if (lbalen->flags & SWS_NDOB) {
1356 				memset(buf, 0, cbe_lun->blocksize);
1357 			} else {
1358 				memcpy(buf, io->scsiio.kern_data_ptr,
1359 				    cbe_lun->blocksize);
1360 			}
1361 			if (lbalen->flags & SWS_LBDATA)
1362 				scsi_ulto4b(lbalen->lba + lba, buf);
1363 			lba++;
1364 		}
1365 	}
1366 
1367 	beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1368 	beio->io_len = lba * cbe_lun->blocksize;
1369 
1370 	/* We can not do all in one run. Correct and schedule rerun. */
1371 	if (len_left > 0) {
1372 		lbalen->lba += lba;
1373 		lbalen->len -= lba;
1374 		beio->beio_cont = ctl_be_block_cw_done_ws;
1375 	}
1376 
1377 	be_lun->dispatch(be_lun, beio);
1378 }
1379 
1380 static void
1381 ctl_be_block_cw_dispatch_unmap(struct ctl_be_block_lun *be_lun,
1382 			    union ctl_io *io)
1383 {
1384 	struct ctl_be_block_io *beio;
1385 	struct ctl_ptr_len_flags *ptrlen;
1386 
1387 	DPRINTF("entered\n");
1388 
1389 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1390 	ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1391 
1392 	if ((ptrlen->flags & ~SU_ANCHOR) != 0 || be_lun->unmap == NULL) {
1393 		ctl_free_beio(beio);
1394 		ctl_set_invalid_field(&io->scsiio,
1395 				      /*sks_valid*/ 0,
1396 				      /*command*/ 1,
1397 				      /*field*/ 0,
1398 				      /*bit_valid*/ 0,
1399 				      /*bit*/ 0);
1400 		ctl_config_write_done(io);
1401 		return;
1402 	}
1403 
1404 	beio->io_len = 0;
1405 	beio->io_offset = -1;
1406 	beio->bio_cmd = BIO_DELETE;
1407 	beio->ds_trans_type = DEVSTAT_FREE;
1408 	DPRINTF("UNMAP\n");
1409 	be_lun->unmap(be_lun, beio);
1410 }
1411 
1412 static void
1413 ctl_be_block_cr_done(struct ctl_be_block_io *beio)
1414 {
1415 	union ctl_io *io;
1416 
1417 	io = beio->io;
1418 	ctl_free_beio(beio);
1419 	ctl_config_read_done(io);
1420 }
1421 
1422 static void
1423 ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
1424 			 union ctl_io *io)
1425 {
1426 	struct ctl_be_block_io *beio;
1427 	struct ctl_be_block_softc *softc;
1428 
1429 	DPRINTF("entered\n");
1430 
1431 	softc = be_lun->softc;
1432 	beio = ctl_alloc_beio(softc);
1433 	beio->io = io;
1434 	beio->lun = be_lun;
1435 	beio->beio_cont = ctl_be_block_cr_done;
1436 	PRIV(io)->ptr = (void *)beio;
1437 
1438 	switch (io->scsiio.cdb[0]) {
1439 	case SERVICE_ACTION_IN:		/* GET LBA STATUS */
1440 		beio->bio_cmd = -1;
1441 		beio->ds_trans_type = DEVSTAT_NO_DATA;
1442 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1443 		beio->io_len = 0;
1444 		if (be_lun->get_lba_status)
1445 			be_lun->get_lba_status(be_lun, beio);
1446 		else
1447 			ctl_be_block_cr_done(beio);
1448 		break;
1449 	default:
1450 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1451 		break;
1452 	}
1453 }
1454 
1455 static void
1456 ctl_be_block_cw_done(struct ctl_be_block_io *beio)
1457 {
1458 	union ctl_io *io;
1459 
1460 	io = beio->io;
1461 	ctl_free_beio(beio);
1462 	ctl_config_write_done(io);
1463 }
1464 
1465 static void
1466 ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
1467 			 union ctl_io *io)
1468 {
1469 	struct ctl_be_block_io *beio;
1470 	struct ctl_be_block_softc *softc;
1471 
1472 	DPRINTF("entered\n");
1473 
1474 	softc = be_lun->softc;
1475 	beio = ctl_alloc_beio(softc);
1476 	beio->io = io;
1477 	beio->lun = be_lun;
1478 	beio->beio_cont = ctl_be_block_cw_done;
1479 	switch (io->scsiio.tag_type) {
1480 	case CTL_TAG_ORDERED:
1481 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1482 		break;
1483 	case CTL_TAG_HEAD_OF_QUEUE:
1484 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1485 		break;
1486 	case CTL_TAG_UNTAGGED:
1487 	case CTL_TAG_SIMPLE:
1488 	case CTL_TAG_ACA:
1489 	default:
1490 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1491 		break;
1492 	}
1493 	PRIV(io)->ptr = (void *)beio;
1494 
1495 	switch (io->scsiio.cdb[0]) {
1496 	case SYNCHRONIZE_CACHE:
1497 	case SYNCHRONIZE_CACHE_16:
1498 		ctl_be_block_cw_dispatch_sync(be_lun, io);
1499 		break;
1500 	case WRITE_SAME_10:
1501 	case WRITE_SAME_16:
1502 		ctl_be_block_cw_dispatch_ws(be_lun, io);
1503 		break;
1504 	case UNMAP:
1505 		ctl_be_block_cw_dispatch_unmap(be_lun, io);
1506 		break;
1507 	default:
1508 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1509 		break;
1510 	}
1511 }
1512 
1513 SDT_PROBE_DEFINE1(cbb, , read, start, "uint64_t");
1514 SDT_PROBE_DEFINE1(cbb, , write, start, "uint64_t");
1515 SDT_PROBE_DEFINE1(cbb, , read, alloc_done, "uint64_t");
1516 SDT_PROBE_DEFINE1(cbb, , write, alloc_done, "uint64_t");
1517 
1518 static void
1519 ctl_be_block_next(struct ctl_be_block_io *beio)
1520 {
1521 	struct ctl_be_block_lun *be_lun;
1522 	union ctl_io *io;
1523 
1524 	io = beio->io;
1525 	be_lun = beio->lun;
1526 	ctl_free_beio(beio);
1527 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1528 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1529 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1530 		ctl_data_submit_done(io);
1531 		return;
1532 	}
1533 
1534 	io->io_hdr.status &= ~CTL_STATUS_MASK;
1535 	io->io_hdr.status |= CTL_STATUS_NONE;
1536 
1537 	mtx_lock(&be_lun->queue_lock);
1538 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1539 	mtx_unlock(&be_lun->queue_lock);
1540 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1541 }
1542 
1543 static void
1544 ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
1545 			   union ctl_io *io)
1546 {
1547 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1548 	struct ctl_be_block_io *beio;
1549 	struct ctl_be_block_softc *softc;
1550 	struct ctl_lba_len_flags *lbalen;
1551 	struct ctl_ptr_len_flags *bptrlen;
1552 	uint64_t len_left, lbas;
1553 	int i;
1554 
1555 	softc = be_lun->softc;
1556 
1557 	DPRINTF("entered\n");
1558 
1559 	lbalen = ARGS(io);
1560 	if (lbalen->flags & CTL_LLF_WRITE) {
1561 		SDT_PROBE0(cbb, , write, start);
1562 	} else {
1563 		SDT_PROBE0(cbb, , read, start);
1564 	}
1565 
1566 	beio = ctl_alloc_beio(softc);
1567 	beio->io = io;
1568 	beio->lun = be_lun;
1569 	bptrlen = PRIV(io);
1570 	bptrlen->ptr = (void *)beio;
1571 
1572 	switch (io->scsiio.tag_type) {
1573 	case CTL_TAG_ORDERED:
1574 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1575 		break;
1576 	case CTL_TAG_HEAD_OF_QUEUE:
1577 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1578 		break;
1579 	case CTL_TAG_UNTAGGED:
1580 	case CTL_TAG_SIMPLE:
1581 	case CTL_TAG_ACA:
1582 	default:
1583 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1584 		break;
1585 	}
1586 
1587 	if (lbalen->flags & CTL_LLF_WRITE) {
1588 		beio->bio_cmd = BIO_WRITE;
1589 		beio->ds_trans_type = DEVSTAT_WRITE;
1590 	} else {
1591 		beio->bio_cmd = BIO_READ;
1592 		beio->ds_trans_type = DEVSTAT_READ;
1593 	}
1594 
1595 	DPRINTF("%s at LBA %jx len %u @%ju\n",
1596 	       (beio->bio_cmd == BIO_READ) ? "READ" : "WRITE",
1597 	       (uintmax_t)lbalen->lba, lbalen->len, bptrlen->len);
1598 	if (lbalen->flags & CTL_LLF_COMPARE) {
1599 		beio->two_sglists = 1;
1600 		lbas = CTLBLK_HALF_IO_SIZE;
1601 	} else {
1602 		lbas = CTLBLK_MAX_IO_SIZE;
1603 	}
1604 	lbas = MIN(lbalen->len - bptrlen->len, lbas / cbe_lun->blocksize);
1605 	beio->io_offset = (lbalen->lba + bptrlen->len) * cbe_lun->blocksize;
1606 	beio->io_len = lbas * cbe_lun->blocksize;
1607 	bptrlen->len += lbas;
1608 
1609 	for (i = 0, len_left = beio->io_len; len_left > 0; i++) {
1610 		KASSERT(i < CTLBLK_MAX_SEGS, ("Too many segs (%d >= %d)",
1611 		    i, CTLBLK_MAX_SEGS));
1612 
1613 		/*
1614 		 * Setup the S/G entry for this chunk.
1615 		 */
1616 		ctl_alloc_seg(softc, &beio->sg_segs[i],
1617 		    MIN(CTLBLK_MAX_SEG, len_left));
1618 
1619 		DPRINTF("segment %d addr %p len %zd\n", i,
1620 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1621 
1622 		/* Set up second segment for compare operation. */
1623 		if (beio->two_sglists) {
1624 			ctl_alloc_seg(softc,
1625 			    &beio->sg_segs[i + CTLBLK_HALF_SEGS],
1626 			    beio->sg_segs[i].len);
1627 		}
1628 
1629 		beio->num_segs++;
1630 		len_left -= beio->sg_segs[i].len;
1631 	}
1632 	if (bptrlen->len < lbalen->len)
1633 		beio->beio_cont = ctl_be_block_next;
1634 	io->scsiio.be_move_done = ctl_be_block_move_done;
1635 	/* For compare we have separate S/G lists for read and datamove. */
1636 	if (beio->two_sglists)
1637 		io->scsiio.kern_data_ptr = (uint8_t *)&beio->sg_segs[CTLBLK_HALF_SEGS];
1638 	else
1639 		io->scsiio.kern_data_ptr = (uint8_t *)beio->sg_segs;
1640 	io->scsiio.kern_data_len = beio->io_len;
1641 	io->scsiio.kern_sg_entries = beio->num_segs;
1642 	io->scsiio.kern_data_ref = ctl_refcnt_beio;
1643 	io->scsiio.kern_data_arg = beio;
1644 	io->io_hdr.flags |= CTL_FLAG_ALLOCATED;
1645 
1646 	/*
1647 	 * For the read case, we need to read the data into our buffers and
1648 	 * then we can send it back to the user.  For the write case, we
1649 	 * need to get the data from the user first.
1650 	 */
1651 	if (beio->bio_cmd == BIO_READ) {
1652 		SDT_PROBE0(cbb, , read, alloc_done);
1653 		be_lun->dispatch(be_lun, beio);
1654 	} else {
1655 		SDT_PROBE0(cbb, , write, alloc_done);
1656 		ctl_datamove(io);
1657 	}
1658 }
1659 
1660 static void
1661 ctl_be_block_worker(void *context, int pending)
1662 {
1663 	struct ctl_be_block_lun *be_lun = (struct ctl_be_block_lun *)context;
1664 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1665 	union ctl_io *io;
1666 	struct ctl_be_block_io *beio;
1667 
1668 	DPRINTF("entered\n");
1669 	/*
1670 	 * Fetch and process I/Os from all queues.  If we detect LUN
1671 	 * CTL_LUN_FLAG_NO_MEDIA status here -- it is result of a race,
1672 	 * so make response maximally opaque to not confuse initiator.
1673 	 */
1674 	for (;;) {
1675 		mtx_lock(&be_lun->queue_lock);
1676 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->datamove_queue);
1677 		if (io != NULL) {
1678 			DPRINTF("datamove queue\n");
1679 			STAILQ_REMOVE_HEAD(&be_lun->datamove_queue, links);
1680 			mtx_unlock(&be_lun->queue_lock);
1681 			beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1682 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1683 				ctl_set_busy(&io->scsiio);
1684 				ctl_complete_beio(beio);
1685 				continue;
1686 			}
1687 			be_lun->dispatch(be_lun, beio);
1688 			continue;
1689 		}
1690 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_write_queue);
1691 		if (io != NULL) {
1692 			DPRINTF("config write queue\n");
1693 			STAILQ_REMOVE_HEAD(&be_lun->config_write_queue, links);
1694 			mtx_unlock(&be_lun->queue_lock);
1695 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1696 				ctl_set_busy(&io->scsiio);
1697 				ctl_config_write_done(io);
1698 				continue;
1699 			}
1700 			ctl_be_block_cw_dispatch(be_lun, io);
1701 			continue;
1702 		}
1703 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_read_queue);
1704 		if (io != NULL) {
1705 			DPRINTF("config read queue\n");
1706 			STAILQ_REMOVE_HEAD(&be_lun->config_read_queue, links);
1707 			mtx_unlock(&be_lun->queue_lock);
1708 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1709 				ctl_set_busy(&io->scsiio);
1710 				ctl_config_read_done(io);
1711 				continue;
1712 			}
1713 			ctl_be_block_cr_dispatch(be_lun, io);
1714 			continue;
1715 		}
1716 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->input_queue);
1717 		if (io != NULL) {
1718 			DPRINTF("input queue\n");
1719 			STAILQ_REMOVE_HEAD(&be_lun->input_queue, links);
1720 			mtx_unlock(&be_lun->queue_lock);
1721 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1722 				ctl_set_busy(&io->scsiio);
1723 				ctl_data_submit_done(io);
1724 				continue;
1725 			}
1726 			ctl_be_block_dispatch(be_lun, io);
1727 			continue;
1728 		}
1729 
1730 		/*
1731 		 * If we get here, there is no work left in the queues, so
1732 		 * just break out and let the task queue go to sleep.
1733 		 */
1734 		mtx_unlock(&be_lun->queue_lock);
1735 		break;
1736 	}
1737 }
1738 
1739 /*
1740  * Entry point from CTL to the backend for I/O.  We queue everything to a
1741  * work thread, so this just puts the I/O on a queue and wakes up the
1742  * thread.
1743  */
1744 static int
1745 ctl_be_block_submit(union ctl_io *io)
1746 {
1747 	struct ctl_be_block_lun *be_lun;
1748 
1749 	DPRINTF("entered\n");
1750 
1751 	be_lun = (struct ctl_be_block_lun *)CTL_BACKEND_LUN(io);
1752 
1753 	KASSERT(io->io_hdr.io_type == CTL_IO_SCSI,
1754 	    ("%s: unexpected I/O type %x", __func__, io->io_hdr.io_type));
1755 
1756 	PRIV(io)->len = 0;
1757 
1758 	mtx_lock(&be_lun->queue_lock);
1759 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1760 	mtx_unlock(&be_lun->queue_lock);
1761 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1762 
1763 	return (CTL_RETVAL_COMPLETE);
1764 }
1765 
1766 static int
1767 ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
1768 			int flag, struct thread *td)
1769 {
1770 	struct ctl_be_block_softc *softc = &backend_block_softc;
1771 	int error;
1772 
1773 	error = 0;
1774 	switch (cmd) {
1775 	case CTL_LUN_REQ: {
1776 		struct ctl_lun_req *lun_req;
1777 
1778 		lun_req = (struct ctl_lun_req *)addr;
1779 
1780 		switch (lun_req->reqtype) {
1781 		case CTL_LUNREQ_CREATE:
1782 			error = ctl_be_block_create(softc, lun_req);
1783 			break;
1784 		case CTL_LUNREQ_RM:
1785 			error = ctl_be_block_rm(softc, lun_req);
1786 			break;
1787 		case CTL_LUNREQ_MODIFY:
1788 			error = ctl_be_block_modify(softc, lun_req);
1789 			break;
1790 		default:
1791 			lun_req->status = CTL_LUN_ERROR;
1792 			snprintf(lun_req->error_str, sizeof(lun_req->error_str),
1793 				 "invalid LUN request type %d",
1794 				 lun_req->reqtype);
1795 			break;
1796 		}
1797 		break;
1798 	}
1799 	default:
1800 		error = ENOTTY;
1801 		break;
1802 	}
1803 
1804 	return (error);
1805 }
1806 
1807 static int
1808 ctl_be_block_open_file(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1809 {
1810 	struct ctl_be_lun *cbe_lun;
1811 	struct ctl_be_block_filedata *file_data;
1812 	struct ctl_lun_create_params *params;
1813 	const char		     *value;
1814 	struct vattr		      vattr;
1815 	off_t			      ps, pss, po, pos, us, uss, uo, uos;
1816 	int			      error;
1817 
1818 	cbe_lun = &be_lun->cbe_lun;
1819 	file_data = &be_lun->backend.file;
1820 	params = &be_lun->params;
1821 
1822 	be_lun->dev_type = CTL_BE_BLOCK_FILE;
1823 	be_lun->dispatch = ctl_be_block_dispatch_file;
1824 	be_lun->lun_flush = ctl_be_block_flush_file;
1825 	be_lun->get_lba_status = ctl_be_block_gls_file;
1826 	be_lun->getattr = ctl_be_block_getattr_file;
1827 	be_lun->unmap = NULL;
1828 	cbe_lun->flags &= ~CTL_LUN_FLAG_UNMAP;
1829 
1830 	error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
1831 	if (error != 0) {
1832 		snprintf(req->error_str, sizeof(req->error_str),
1833 			 "error calling VOP_GETATTR() for file %s",
1834 			 be_lun->dev_path);
1835 		return (error);
1836 	}
1837 
1838 	file_data->cred = crhold(curthread->td_ucred);
1839 	if (params->lun_size_bytes != 0)
1840 		be_lun->size_bytes = params->lun_size_bytes;
1841 	else
1842 		be_lun->size_bytes = vattr.va_size;
1843 
1844 	/*
1845 	 * For files we can use any logical block size.  Prefer 512 bytes
1846 	 * for compatibility reasons.  If file's vattr.va_blocksize
1847 	 * (preferred I/O block size) is bigger and multiple to chosen
1848 	 * logical block size -- report it as physical block size.
1849 	 */
1850 	if (params->blocksize_bytes != 0)
1851 		cbe_lun->blocksize = params->blocksize_bytes;
1852 	else if (cbe_lun->lun_type == T_CDROM)
1853 		cbe_lun->blocksize = 2048;
1854 	else
1855 		cbe_lun->blocksize = 512;
1856 	be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
1857 	cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
1858 	    0 : (be_lun->size_blocks - 1);
1859 
1860 	us = ps = vattr.va_blocksize;
1861 	uo = po = 0;
1862 
1863 	value = dnvlist_get_string(cbe_lun->options, "pblocksize", NULL);
1864 	if (value != NULL)
1865 		ctl_expand_number(value, &ps);
1866 	value = dnvlist_get_string(cbe_lun->options, "pblockoffset", NULL);
1867 	if (value != NULL)
1868 		ctl_expand_number(value, &po);
1869 	pss = ps / cbe_lun->blocksize;
1870 	pos = po / cbe_lun->blocksize;
1871 	if ((pss > 0) && (pss * cbe_lun->blocksize == ps) && (pss >= pos) &&
1872 	    ((pss & (pss - 1)) == 0) && (pos * cbe_lun->blocksize == po)) {
1873 		cbe_lun->pblockexp = fls(pss) - 1;
1874 		cbe_lun->pblockoff = (pss - pos) % pss;
1875 	}
1876 
1877 	value = dnvlist_get_string(cbe_lun->options, "ublocksize", NULL);
1878 	if (value != NULL)
1879 		ctl_expand_number(value, &us);
1880 	value = dnvlist_get_string(cbe_lun->options, "ublockoffset", NULL);
1881 	if (value != NULL)
1882 		ctl_expand_number(value, &uo);
1883 	uss = us / cbe_lun->blocksize;
1884 	uos = uo / cbe_lun->blocksize;
1885 	if ((uss > 0) && (uss * cbe_lun->blocksize == us) && (uss >= uos) &&
1886 	    ((uss & (uss - 1)) == 0) && (uos * cbe_lun->blocksize == uo)) {
1887 		cbe_lun->ublockexp = fls(uss) - 1;
1888 		cbe_lun->ublockoff = (uss - uos) % uss;
1889 	}
1890 
1891 	/*
1892 	 * Sanity check.  The media size has to be at least one
1893 	 * sector long.
1894 	 */
1895 	if (be_lun->size_bytes < cbe_lun->blocksize) {
1896 		error = EINVAL;
1897 		snprintf(req->error_str, sizeof(req->error_str),
1898 			 "file %s size %ju < block size %u", be_lun->dev_path,
1899 			 (uintmax_t)be_lun->size_bytes, cbe_lun->blocksize);
1900 	}
1901 
1902 	cbe_lun->opttxferlen = CTLBLK_MAX_IO_SIZE / cbe_lun->blocksize;
1903 	return (error);
1904 }
1905 
1906 static int
1907 ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1908 {
1909 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1910 	struct ctl_lun_create_params *params;
1911 	struct cdevsw		     *csw;
1912 	struct cdev		     *dev;
1913 	const char		     *value;
1914 	int			      error, atomic, maxio, ref, unmap, tmp;
1915 	off_t			      ps, pss, po, pos, us, uss, uo, uos, otmp;
1916 
1917 	params = &be_lun->params;
1918 
1919 	be_lun->dev_type = CTL_BE_BLOCK_DEV;
1920 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1921 	if (csw == NULL)
1922 		return (ENXIO);
1923 	if (strcmp(csw->d_name, "zvol") == 0) {
1924 		be_lun->dispatch = ctl_be_block_dispatch_zvol;
1925 		be_lun->get_lba_status = ctl_be_block_gls_zvol;
1926 		atomic = maxio = CTLBLK_MAX_IO_SIZE;
1927 	} else {
1928 		be_lun->dispatch = ctl_be_block_dispatch_dev;
1929 		be_lun->get_lba_status = NULL;
1930 		atomic = 0;
1931 		maxio = dev->si_iosize_max;
1932 		if (maxio <= 0)
1933 			maxio = DFLTPHYS;
1934 		if (maxio > CTLBLK_MAX_SEG)
1935 			maxio = CTLBLK_MAX_SEG;
1936 	}
1937 	be_lun->lun_flush = ctl_be_block_flush_dev;
1938 	be_lun->getattr = ctl_be_block_getattr_dev;
1939 	be_lun->unmap = ctl_be_block_unmap_dev;
1940 
1941 	if (!csw->d_ioctl) {
1942 		dev_relthread(dev, ref);
1943 		snprintf(req->error_str, sizeof(req->error_str),
1944 			 "no d_ioctl for device %s!", be_lun->dev_path);
1945 		return (ENODEV);
1946 	}
1947 
1948 	error = csw->d_ioctl(dev, DIOCGSECTORSIZE, (caddr_t)&tmp, FREAD,
1949 			       curthread);
1950 	if (error) {
1951 		dev_relthread(dev, ref);
1952 		snprintf(req->error_str, sizeof(req->error_str),
1953 			 "error %d returned for DIOCGSECTORSIZE ioctl "
1954 			 "on %s!", error, be_lun->dev_path);
1955 		return (error);
1956 	}
1957 
1958 	/*
1959 	 * If the user has asked for a blocksize that is greater than the
1960 	 * backing device's blocksize, we can do it only if the blocksize
1961 	 * the user is asking for is an even multiple of the underlying
1962 	 * device's blocksize.
1963 	 */
1964 	if ((params->blocksize_bytes != 0) &&
1965 	    (params->blocksize_bytes >= tmp)) {
1966 		if (params->blocksize_bytes % tmp == 0) {
1967 			cbe_lun->blocksize = params->blocksize_bytes;
1968 		} else {
1969 			dev_relthread(dev, ref);
1970 			snprintf(req->error_str, sizeof(req->error_str),
1971 				 "requested blocksize %u is not an even "
1972 				 "multiple of backing device blocksize %u",
1973 				 params->blocksize_bytes, tmp);
1974 			return (EINVAL);
1975 		}
1976 	} else if (params->blocksize_bytes != 0) {
1977 		dev_relthread(dev, ref);
1978 		snprintf(req->error_str, sizeof(req->error_str),
1979 			 "requested blocksize %u < backing device "
1980 			 "blocksize %u", params->blocksize_bytes, tmp);
1981 		return (EINVAL);
1982 	} else if (cbe_lun->lun_type == T_CDROM)
1983 		cbe_lun->blocksize = MAX(tmp, 2048);
1984 	else
1985 		cbe_lun->blocksize = tmp;
1986 
1987 	error = csw->d_ioctl(dev, DIOCGMEDIASIZE, (caddr_t)&otmp, FREAD,
1988 			     curthread);
1989 	if (error) {
1990 		dev_relthread(dev, ref);
1991 		snprintf(req->error_str, sizeof(req->error_str),
1992 			 "error %d returned for DIOCGMEDIASIZE "
1993 			 " ioctl on %s!", error,
1994 			 be_lun->dev_path);
1995 		return (error);
1996 	}
1997 
1998 	if (params->lun_size_bytes != 0) {
1999 		if (params->lun_size_bytes > otmp) {
2000 			dev_relthread(dev, ref);
2001 			snprintf(req->error_str, sizeof(req->error_str),
2002 				 "requested LUN size %ju > backing device "
2003 				 "size %ju",
2004 				 (uintmax_t)params->lun_size_bytes,
2005 				 (uintmax_t)otmp);
2006 			return (EINVAL);
2007 		}
2008 
2009 		be_lun->size_bytes = params->lun_size_bytes;
2010 	} else
2011 		be_lun->size_bytes = otmp;
2012 	be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
2013 	cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
2014 	    0 : (be_lun->size_blocks - 1);
2015 
2016 	error = csw->d_ioctl(dev, DIOCGSTRIPESIZE, (caddr_t)&ps, FREAD,
2017 	    curthread);
2018 	if (error)
2019 		ps = po = 0;
2020 	else {
2021 		error = csw->d_ioctl(dev, DIOCGSTRIPEOFFSET, (caddr_t)&po,
2022 		    FREAD, curthread);
2023 		if (error)
2024 			po = 0;
2025 	}
2026 	us = ps;
2027 	uo = po;
2028 
2029 	value = dnvlist_get_string(cbe_lun->options, "pblocksize", NULL);
2030 	if (value != NULL)
2031 		ctl_expand_number(value, &ps);
2032 	value = dnvlist_get_string(cbe_lun->options, "pblockoffset", NULL);
2033 	if (value != NULL)
2034 		ctl_expand_number(value, &po);
2035 	pss = ps / cbe_lun->blocksize;
2036 	pos = po / cbe_lun->blocksize;
2037 	if ((pss > 0) && (pss * cbe_lun->blocksize == ps) && (pss >= pos) &&
2038 	    ((pss & (pss - 1)) == 0) && (pos * cbe_lun->blocksize == po)) {
2039 		cbe_lun->pblockexp = fls(pss) - 1;
2040 		cbe_lun->pblockoff = (pss - pos) % pss;
2041 	}
2042 
2043 	value = dnvlist_get_string(cbe_lun->options, "ublocksize", NULL);
2044 	if (value != NULL)
2045 		ctl_expand_number(value, &us);
2046 	value = dnvlist_get_string(cbe_lun->options, "ublockoffset", NULL);
2047 	if (value != NULL)
2048 		ctl_expand_number(value, &uo);
2049 	uss = us / cbe_lun->blocksize;
2050 	uos = uo / cbe_lun->blocksize;
2051 	if ((uss > 0) && (uss * cbe_lun->blocksize == us) && (uss >= uos) &&
2052 	    ((uss & (uss - 1)) == 0) && (uos * cbe_lun->blocksize == uo)) {
2053 		cbe_lun->ublockexp = fls(uss) - 1;
2054 		cbe_lun->ublockoff = (uss - uos) % uss;
2055 	}
2056 
2057 	cbe_lun->atomicblock = atomic / cbe_lun->blocksize;
2058 	cbe_lun->opttxferlen = maxio / cbe_lun->blocksize;
2059 
2060 	if (be_lun->dispatch == ctl_be_block_dispatch_zvol) {
2061 		unmap = 1;
2062 	} else {
2063 		struct diocgattr_arg	arg;
2064 
2065 		strlcpy(arg.name, "GEOM::candelete", sizeof(arg.name));
2066 		arg.len = sizeof(arg.value.i);
2067 		error = csw->d_ioctl(dev, DIOCGATTR, (caddr_t)&arg, FREAD,
2068 		    curthread);
2069 		unmap = (error == 0) ? arg.value.i : 0;
2070 	}
2071 	value = dnvlist_get_string(cbe_lun->options, "unmap", NULL);
2072 	if (value != NULL)
2073 		unmap = (strcmp(value, "on") == 0);
2074 	if (unmap)
2075 		cbe_lun->flags |= CTL_LUN_FLAG_UNMAP;
2076 	else
2077 		cbe_lun->flags &= ~CTL_LUN_FLAG_UNMAP;
2078 
2079 	dev_relthread(dev, ref);
2080 	return (0);
2081 }
2082 
2083 static int
2084 ctl_be_block_close(struct ctl_be_block_lun *be_lun)
2085 {
2086 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
2087 	int flags;
2088 
2089 	if (be_lun->vn) {
2090 		flags = FREAD;
2091 		if ((cbe_lun->flags & CTL_LUN_FLAG_READONLY) == 0)
2092 			flags |= FWRITE;
2093 		(void)vn_close(be_lun->vn, flags, NOCRED, curthread);
2094 		be_lun->vn = NULL;
2095 
2096 		switch (be_lun->dev_type) {
2097 		case CTL_BE_BLOCK_DEV:
2098 			break;
2099 		case CTL_BE_BLOCK_FILE:
2100 			if (be_lun->backend.file.cred != NULL) {
2101 				crfree(be_lun->backend.file.cred);
2102 				be_lun->backend.file.cred = NULL;
2103 			}
2104 			break;
2105 		case CTL_BE_BLOCK_NONE:
2106 			break;
2107 		default:
2108 			panic("Unexpected backend type %d", be_lun->dev_type);
2109 			break;
2110 		}
2111 		be_lun->dev_type = CTL_BE_BLOCK_NONE;
2112 	}
2113 	return (0);
2114 }
2115 
2116 static int
2117 ctl_be_block_open(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
2118 {
2119 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
2120 	struct nameidata nd;
2121 	const char	*value;
2122 	int		 error, flags;
2123 
2124 	error = 0;
2125 	if (rootvnode == NULL) {
2126 		snprintf(req->error_str, sizeof(req->error_str),
2127 			 "Root filesystem is not mounted");
2128 		return (1);
2129 	}
2130 	pwd_ensure_dirs();
2131 
2132 	value = dnvlist_get_string(cbe_lun->options, "file", NULL);
2133 	if (value == NULL) {
2134 		snprintf(req->error_str, sizeof(req->error_str),
2135 			 "no file argument specified");
2136 		return (1);
2137 	}
2138 	free(be_lun->dev_path, M_CTLBLK);
2139 	be_lun->dev_path = strdup(value, M_CTLBLK);
2140 
2141 	flags = FREAD;
2142 	value = dnvlist_get_string(cbe_lun->options, "readonly", NULL);
2143 	if (value != NULL) {
2144 		if (strcmp(value, "on") != 0)
2145 			flags |= FWRITE;
2146 	} else if (cbe_lun->lun_type == T_DIRECT)
2147 		flags |= FWRITE;
2148 
2149 again:
2150 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, be_lun->dev_path, curthread);
2151 	error = vn_open(&nd, &flags, 0, NULL);
2152 	if ((error == EROFS || error == EACCES) && (flags & FWRITE)) {
2153 		flags &= ~FWRITE;
2154 		goto again;
2155 	}
2156 	if (error) {
2157 		/*
2158 		 * This is the only reasonable guess we can make as far as
2159 		 * path if the user doesn't give us a fully qualified path.
2160 		 * If they want to specify a file, they need to specify the
2161 		 * full path.
2162 		 */
2163 		if (be_lun->dev_path[0] != '/') {
2164 			char *dev_name;
2165 
2166 			asprintf(&dev_name, M_CTLBLK, "/dev/%s",
2167 				be_lun->dev_path);
2168 			free(be_lun->dev_path, M_CTLBLK);
2169 			be_lun->dev_path = dev_name;
2170 			goto again;
2171 		}
2172 		snprintf(req->error_str, sizeof(req->error_str),
2173 		    "error opening %s: %d", be_lun->dev_path, error);
2174 		return (error);
2175 	}
2176 	if (flags & FWRITE)
2177 		cbe_lun->flags &= ~CTL_LUN_FLAG_READONLY;
2178 	else
2179 		cbe_lun->flags |= CTL_LUN_FLAG_READONLY;
2180 
2181 	NDFREE(&nd, NDF_ONLY_PNBUF);
2182 	be_lun->vn = nd.ni_vp;
2183 
2184 	/* We only support disks and files. */
2185 	if (vn_isdisk_error(be_lun->vn, &error)) {
2186 		error = ctl_be_block_open_dev(be_lun, req);
2187 	} else if (be_lun->vn->v_type == VREG) {
2188 		error = ctl_be_block_open_file(be_lun, req);
2189 	} else {
2190 		error = EINVAL;
2191 		snprintf(req->error_str, sizeof(req->error_str),
2192 			 "%s is not a disk or plain file", be_lun->dev_path);
2193 	}
2194 	VOP_UNLOCK(be_lun->vn);
2195 
2196 	if (error != 0)
2197 		ctl_be_block_close(be_lun);
2198 	cbe_lun->serseq = CTL_LUN_SERSEQ_OFF;
2199 	if (be_lun->dispatch != ctl_be_block_dispatch_dev)
2200 		cbe_lun->serseq = CTL_LUN_SERSEQ_SOFT;
2201 	value = dnvlist_get_string(cbe_lun->options, "serseq", NULL);
2202 	if (value != NULL && strcmp(value, "on") == 0)
2203 		cbe_lun->serseq = CTL_LUN_SERSEQ_ON;
2204 	else if (value != NULL && strcmp(value, "read") == 0)
2205 		cbe_lun->serseq = CTL_LUN_SERSEQ_READ;
2206 	else if (value != NULL && strcmp(value, "soft") == 0)
2207 		cbe_lun->serseq = CTL_LUN_SERSEQ_SOFT;
2208 	else if (value != NULL && strcmp(value, "off") == 0)
2209 		cbe_lun->serseq = CTL_LUN_SERSEQ_OFF;
2210 	return (0);
2211 }
2212 
2213 static int
2214 ctl_be_block_create(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2215 {
2216 	struct ctl_be_lun *cbe_lun;
2217 	struct ctl_be_block_lun *be_lun;
2218 	struct ctl_lun_create_params *params;
2219 	char num_thread_str[16];
2220 	char tmpstr[32];
2221 	const char *value;
2222 	int retval, num_threads;
2223 	int tmp_num_threads;
2224 
2225 	params = &req->reqdata.create;
2226 	retval = 0;
2227 	req->status = CTL_LUN_OK;
2228 
2229 	be_lun = malloc(sizeof(*be_lun), M_CTLBLK, M_ZERO | M_WAITOK);
2230 	cbe_lun = &be_lun->cbe_lun;
2231 	be_lun->params = req->reqdata.create;
2232 	be_lun->softc = softc;
2233 	STAILQ_INIT(&be_lun->input_queue);
2234 	STAILQ_INIT(&be_lun->config_read_queue);
2235 	STAILQ_INIT(&be_lun->config_write_queue);
2236 	STAILQ_INIT(&be_lun->datamove_queue);
2237 	mtx_init(&be_lun->io_lock, "ctlblock io", NULL, MTX_DEF);
2238 	mtx_init(&be_lun->queue_lock, "ctlblock queue", NULL, MTX_DEF);
2239 	cbe_lun->options = nvlist_clone(req->args_nvl);
2240 
2241 	if (params->flags & CTL_LUN_FLAG_DEV_TYPE)
2242 		cbe_lun->lun_type = params->device_type;
2243 	else
2244 		cbe_lun->lun_type = T_DIRECT;
2245 	be_lun->flags = 0;
2246 	cbe_lun->flags = 0;
2247 	value = dnvlist_get_string(cbe_lun->options, "ha_role", NULL);
2248 	if (value != NULL) {
2249 		if (strcmp(value, "primary") == 0)
2250 			cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2251 	} else if (control_softc->flags & CTL_FLAG_ACTIVE_SHELF)
2252 		cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2253 
2254 	if (cbe_lun->lun_type == T_DIRECT ||
2255 	    cbe_lun->lun_type == T_CDROM) {
2256 		be_lun->size_bytes = params->lun_size_bytes;
2257 		if (params->blocksize_bytes != 0)
2258 			cbe_lun->blocksize = params->blocksize_bytes;
2259 		else if (cbe_lun->lun_type == T_CDROM)
2260 			cbe_lun->blocksize = 2048;
2261 		else
2262 			cbe_lun->blocksize = 512;
2263 		be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
2264 		cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
2265 		    0 : (be_lun->size_blocks - 1);
2266 
2267 		if ((cbe_lun->flags & CTL_LUN_FLAG_PRIMARY) ||
2268 		    control_softc->ha_mode == CTL_HA_MODE_SER_ONLY) {
2269 			retval = ctl_be_block_open(be_lun, req);
2270 			if (retval != 0) {
2271 				retval = 0;
2272 				req->status = CTL_LUN_WARNING;
2273 			}
2274 		}
2275 		num_threads = cbb_num_threads;
2276 	} else {
2277 		num_threads = 1;
2278 	}
2279 
2280 	value = dnvlist_get_string(cbe_lun->options, "num_threads", NULL);
2281 	if (value != NULL) {
2282 		tmp_num_threads = strtol(value, NULL, 0);
2283 
2284 		/*
2285 		 * We don't let the user specify less than one
2286 		 * thread, but hope he's clueful enough not to
2287 		 * specify 1000 threads.
2288 		 */
2289 		if (tmp_num_threads < 1) {
2290 			snprintf(req->error_str, sizeof(req->error_str),
2291 				 "invalid number of threads %s",
2292 				 num_thread_str);
2293 			goto bailout_error;
2294 		}
2295 		num_threads = tmp_num_threads;
2296 	}
2297 
2298 	if (be_lun->vn == NULL)
2299 		cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2300 	/* Tell the user the blocksize we ended up using */
2301 	params->lun_size_bytes = be_lun->size_bytes;
2302 	params->blocksize_bytes = cbe_lun->blocksize;
2303 	if (params->flags & CTL_LUN_FLAG_ID_REQ) {
2304 		cbe_lun->req_lun_id = params->req_lun_id;
2305 		cbe_lun->flags |= CTL_LUN_FLAG_ID_REQ;
2306 	} else
2307 		cbe_lun->req_lun_id = 0;
2308 
2309 	cbe_lun->lun_shutdown = ctl_be_block_lun_shutdown;
2310 	cbe_lun->be = &ctl_be_block_driver;
2311 
2312 	if ((params->flags & CTL_LUN_FLAG_SERIAL_NUM) == 0) {
2313 		snprintf(tmpstr, sizeof(tmpstr), "MYSERIAL%04d",
2314 			 softc->num_luns);
2315 		strncpy((char *)cbe_lun->serial_num, tmpstr,
2316 			MIN(sizeof(cbe_lun->serial_num), sizeof(tmpstr)));
2317 
2318 		/* Tell the user what we used for a serial number */
2319 		strncpy((char *)params->serial_num, tmpstr,
2320 			MIN(sizeof(params->serial_num), sizeof(tmpstr)));
2321 	} else {
2322 		strncpy((char *)cbe_lun->serial_num, params->serial_num,
2323 			MIN(sizeof(cbe_lun->serial_num),
2324 			sizeof(params->serial_num)));
2325 	}
2326 	if ((params->flags & CTL_LUN_FLAG_DEVID) == 0) {
2327 		snprintf(tmpstr, sizeof(tmpstr), "MYDEVID%04d", softc->num_luns);
2328 		strncpy((char *)cbe_lun->device_id, tmpstr,
2329 			MIN(sizeof(cbe_lun->device_id), sizeof(tmpstr)));
2330 
2331 		/* Tell the user what we used for a device ID */
2332 		strncpy((char *)params->device_id, tmpstr,
2333 			MIN(sizeof(params->device_id), sizeof(tmpstr)));
2334 	} else {
2335 		strncpy((char *)cbe_lun->device_id, params->device_id,
2336 			MIN(sizeof(cbe_lun->device_id),
2337 			    sizeof(params->device_id)));
2338 	}
2339 
2340 	TASK_INIT(&be_lun->io_task, /*priority*/0, ctl_be_block_worker, be_lun);
2341 
2342 	be_lun->io_taskqueue = taskqueue_create("ctlblocktq", M_WAITOK,
2343 	    taskqueue_thread_enqueue, /*context*/&be_lun->io_taskqueue);
2344 
2345 	if (be_lun->io_taskqueue == NULL) {
2346 		snprintf(req->error_str, sizeof(req->error_str),
2347 			 "unable to create taskqueue");
2348 		goto bailout_error;
2349 	}
2350 
2351 	/*
2352 	 * Note that we start the same number of threads by default for
2353 	 * both the file case and the block device case.  For the file
2354 	 * case, we need multiple threads to allow concurrency, because the
2355 	 * vnode interface is designed to be a blocking interface.  For the
2356 	 * block device case, ZFS zvols at least will block the caller's
2357 	 * context in many instances, and so we need multiple threads to
2358 	 * overcome that problem.  Other block devices don't need as many
2359 	 * threads, but they shouldn't cause too many problems.
2360 	 *
2361 	 * If the user wants to just have a single thread for a block
2362 	 * device, he can specify that when the LUN is created, or change
2363 	 * the tunable/sysctl to alter the default number of threads.
2364 	 */
2365 	retval = taskqueue_start_threads_in_proc(&be_lun->io_taskqueue,
2366 					 /*num threads*/num_threads,
2367 					 /*priority*/PUSER,
2368 					 /*proc*/control_softc->ctl_proc,
2369 					 /*thread name*/"block");
2370 
2371 	if (retval != 0)
2372 		goto bailout_error;
2373 
2374 	be_lun->num_threads = num_threads;
2375 
2376 	retval = ctl_add_lun(&be_lun->cbe_lun);
2377 	if (retval != 0) {
2378 		snprintf(req->error_str, sizeof(req->error_str),
2379 			 "ctl_add_lun() returned error %d, see dmesg for "
2380 			 "details", retval);
2381 		retval = 0;
2382 		goto bailout_error;
2383 	}
2384 
2385 	be_lun->disk_stats = devstat_new_entry("cbb", cbe_lun->lun_id,
2386 					       cbe_lun->blocksize,
2387 					       DEVSTAT_ALL_SUPPORTED,
2388 					       cbe_lun->lun_type
2389 					       | DEVSTAT_TYPE_IF_OTHER,
2390 					       DEVSTAT_PRIORITY_OTHER);
2391 
2392 	mtx_lock(&softc->lock);
2393 	softc->num_luns++;
2394 	SLIST_INSERT_HEAD(&softc->lun_list, be_lun, links);
2395 	mtx_unlock(&softc->lock);
2396 
2397 	params->req_lun_id = cbe_lun->lun_id;
2398 
2399 	return (retval);
2400 
2401 bailout_error:
2402 	req->status = CTL_LUN_ERROR;
2403 
2404 	if (be_lun->io_taskqueue != NULL)
2405 		taskqueue_free(be_lun->io_taskqueue);
2406 	ctl_be_block_close(be_lun);
2407 	if (be_lun->dev_path != NULL)
2408 		free(be_lun->dev_path, M_CTLBLK);
2409 	nvlist_destroy(cbe_lun->options);
2410 	mtx_destroy(&be_lun->queue_lock);
2411 	mtx_destroy(&be_lun->io_lock);
2412 	free(be_lun, M_CTLBLK);
2413 
2414 	return (retval);
2415 }
2416 
2417 static int
2418 ctl_be_block_rm(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2419 {
2420 	struct ctl_lun_rm_params *params;
2421 	struct ctl_be_block_lun *be_lun;
2422 	struct ctl_be_lun *cbe_lun;
2423 	int retval;
2424 
2425 	params = &req->reqdata.rm;
2426 
2427 	sx_xlock(&softc->modify_lock);
2428 	mtx_lock(&softc->lock);
2429 	SLIST_FOREACH(be_lun, &softc->lun_list, links) {
2430 		if (be_lun->cbe_lun.lun_id == params->lun_id) {
2431 			SLIST_REMOVE(&softc->lun_list, be_lun,
2432 			    ctl_be_block_lun, links);
2433 			softc->num_luns--;
2434 			break;
2435 		}
2436 	}
2437 	mtx_unlock(&softc->lock);
2438 	sx_xunlock(&softc->modify_lock);
2439 	if (be_lun == NULL) {
2440 		snprintf(req->error_str, sizeof(req->error_str),
2441 			 "LUN %u is not managed by the block backend",
2442 			 params->lun_id);
2443 		goto bailout_error;
2444 	}
2445 	cbe_lun = &be_lun->cbe_lun;
2446 
2447 	if (be_lun->vn != NULL) {
2448 		cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2449 		ctl_lun_no_media(cbe_lun);
2450 		taskqueue_drain_all(be_lun->io_taskqueue);
2451 		ctl_be_block_close(be_lun);
2452 	}
2453 
2454 	mtx_lock(&softc->lock);
2455 	be_lun->flags |= CTL_BE_BLOCK_LUN_WAITING;
2456 	mtx_unlock(&softc->lock);
2457 
2458 	retval = ctl_remove_lun(cbe_lun);
2459 	if (retval != 0) {
2460 		snprintf(req->error_str, sizeof(req->error_str),
2461 			 "error %d returned from ctl_remove_lun() for "
2462 			 "LUN %d", retval, params->lun_id);
2463 		mtx_lock(&softc->lock);
2464 		be_lun->flags &= ~CTL_BE_BLOCK_LUN_WAITING;
2465 		mtx_unlock(&softc->lock);
2466 		goto bailout_error;
2467 	}
2468 
2469 	mtx_lock(&softc->lock);
2470 	while ((be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) == 0) {
2471 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlblockrm", 0);
2472 		if (retval == EINTR)
2473 			break;
2474 	}
2475 	be_lun->flags &= ~CTL_BE_BLOCK_LUN_WAITING;
2476 	if (be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) {
2477 		mtx_unlock(&softc->lock);
2478 		free(be_lun, M_CTLBLK);
2479 	} else {
2480 		mtx_unlock(&softc->lock);
2481 		return (EINTR);
2482 	}
2483 
2484 	req->status = CTL_LUN_OK;
2485 	return (0);
2486 
2487 bailout_error:
2488 	req->status = CTL_LUN_ERROR;
2489 	return (0);
2490 }
2491 
2492 static int
2493 ctl_be_block_modify(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2494 {
2495 	struct ctl_lun_modify_params *params;
2496 	struct ctl_be_block_lun *be_lun;
2497 	struct ctl_be_lun *cbe_lun;
2498 	const char *value;
2499 	uint64_t oldsize;
2500 	int error, wasprim;
2501 
2502 	params = &req->reqdata.modify;
2503 
2504 	sx_xlock(&softc->modify_lock);
2505 	mtx_lock(&softc->lock);
2506 	SLIST_FOREACH(be_lun, &softc->lun_list, links) {
2507 		if (be_lun->cbe_lun.lun_id == params->lun_id)
2508 			break;
2509 	}
2510 	mtx_unlock(&softc->lock);
2511 	if (be_lun == NULL) {
2512 		snprintf(req->error_str, sizeof(req->error_str),
2513 			 "LUN %u is not managed by the block backend",
2514 			 params->lun_id);
2515 		goto bailout_error;
2516 	}
2517 	cbe_lun = &be_lun->cbe_lun;
2518 
2519 	if (params->lun_size_bytes != 0)
2520 		be_lun->params.lun_size_bytes = params->lun_size_bytes;
2521 
2522 	if (req->args_nvl != NULL) {
2523 		nvlist_destroy(cbe_lun->options);
2524 		cbe_lun->options = nvlist_clone(req->args_nvl);
2525 	}
2526 
2527 	wasprim = (cbe_lun->flags & CTL_LUN_FLAG_PRIMARY);
2528 	value = dnvlist_get_string(cbe_lun->options, "ha_role", NULL);
2529 	if (value != NULL) {
2530 		if (strcmp(value, "primary") == 0)
2531 			cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2532 		else
2533 			cbe_lun->flags &= ~CTL_LUN_FLAG_PRIMARY;
2534 	} else if (control_softc->flags & CTL_FLAG_ACTIVE_SHELF)
2535 		cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2536 	else
2537 		cbe_lun->flags &= ~CTL_LUN_FLAG_PRIMARY;
2538 	if (wasprim != (cbe_lun->flags & CTL_LUN_FLAG_PRIMARY)) {
2539 		if (cbe_lun->flags & CTL_LUN_FLAG_PRIMARY)
2540 			ctl_lun_primary(cbe_lun);
2541 		else
2542 			ctl_lun_secondary(cbe_lun);
2543 	}
2544 
2545 	oldsize = be_lun->size_blocks;
2546 	if ((cbe_lun->flags & CTL_LUN_FLAG_PRIMARY) ||
2547 	    control_softc->ha_mode == CTL_HA_MODE_SER_ONLY) {
2548 		if (be_lun->vn == NULL)
2549 			error = ctl_be_block_open(be_lun, req);
2550 		else if (vn_isdisk_error(be_lun->vn, &error))
2551 			error = ctl_be_block_open_dev(be_lun, req);
2552 		else if (be_lun->vn->v_type == VREG) {
2553 			vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
2554 			error = ctl_be_block_open_file(be_lun, req);
2555 			VOP_UNLOCK(be_lun->vn);
2556 		} else
2557 			error = EINVAL;
2558 		if ((cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) &&
2559 		    be_lun->vn != NULL) {
2560 			cbe_lun->flags &= ~CTL_LUN_FLAG_NO_MEDIA;
2561 			ctl_lun_has_media(cbe_lun);
2562 		} else if ((cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) == 0 &&
2563 		    be_lun->vn == NULL) {
2564 			cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2565 			ctl_lun_no_media(cbe_lun);
2566 		}
2567 		cbe_lun->flags &= ~CTL_LUN_FLAG_EJECTED;
2568 	} else {
2569 		if (be_lun->vn != NULL) {
2570 			cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2571 			ctl_lun_no_media(cbe_lun);
2572 			taskqueue_drain_all(be_lun->io_taskqueue);
2573 			error = ctl_be_block_close(be_lun);
2574 		} else
2575 			error = 0;
2576 	}
2577 	if (be_lun->size_blocks != oldsize)
2578 		ctl_lun_capacity_changed(cbe_lun);
2579 
2580 	/* Tell the user the exact size we ended up using */
2581 	params->lun_size_bytes = be_lun->size_bytes;
2582 
2583 	sx_xunlock(&softc->modify_lock);
2584 	req->status = error ? CTL_LUN_WARNING : CTL_LUN_OK;
2585 	return (0);
2586 
2587 bailout_error:
2588 	sx_xunlock(&softc->modify_lock);
2589 	req->status = CTL_LUN_ERROR;
2590 	return (0);
2591 }
2592 
2593 static void
2594 ctl_be_block_lun_shutdown(struct ctl_be_lun *cbe_lun)
2595 {
2596 	struct ctl_be_block_lun *be_lun = (struct ctl_be_block_lun *)cbe_lun;
2597 	struct ctl_be_block_softc *softc = be_lun->softc;
2598 
2599 	taskqueue_drain_all(be_lun->io_taskqueue);
2600 	taskqueue_free(be_lun->io_taskqueue);
2601 	if (be_lun->disk_stats != NULL)
2602 		devstat_remove_entry(be_lun->disk_stats);
2603 	nvlist_destroy(be_lun->cbe_lun.options);
2604 	free(be_lun->dev_path, M_CTLBLK);
2605 	mtx_destroy(&be_lun->queue_lock);
2606 	mtx_destroy(&be_lun->io_lock);
2607 
2608 	mtx_lock(&softc->lock);
2609 	be_lun->flags |= CTL_BE_BLOCK_LUN_UNCONFIGURED;
2610 	if (be_lun->flags & CTL_BE_BLOCK_LUN_WAITING)
2611 		wakeup(be_lun);
2612 	else
2613 		free(be_lun, M_CTLBLK);
2614 	mtx_unlock(&softc->lock);
2615 }
2616 
2617 static int
2618 ctl_be_block_config_write(union ctl_io *io)
2619 {
2620 	struct ctl_be_block_lun *be_lun;
2621 	struct ctl_be_lun *cbe_lun;
2622 	int retval;
2623 
2624 	DPRINTF("entered\n");
2625 
2626 	cbe_lun = CTL_BACKEND_LUN(io);
2627 	be_lun = (struct ctl_be_block_lun *)cbe_lun;
2628 
2629 	retval = 0;
2630 	switch (io->scsiio.cdb[0]) {
2631 	case SYNCHRONIZE_CACHE:
2632 	case SYNCHRONIZE_CACHE_16:
2633 	case WRITE_SAME_10:
2634 	case WRITE_SAME_16:
2635 	case UNMAP:
2636 		/*
2637 		 * The upper level CTL code will filter out any CDBs with
2638 		 * the immediate bit set and return the proper error.
2639 		 *
2640 		 * We don't really need to worry about what LBA range the
2641 		 * user asked to be synced out.  When they issue a sync
2642 		 * cache command, we'll sync out the whole thing.
2643 		 */
2644 		mtx_lock(&be_lun->queue_lock);
2645 		STAILQ_INSERT_TAIL(&be_lun->config_write_queue, &io->io_hdr,
2646 				   links);
2647 		mtx_unlock(&be_lun->queue_lock);
2648 		taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
2649 		break;
2650 	case START_STOP_UNIT: {
2651 		struct scsi_start_stop_unit *cdb;
2652 		struct ctl_lun_req req;
2653 
2654 		cdb = (struct scsi_start_stop_unit *)io->scsiio.cdb;
2655 		if ((cdb->how & SSS_PC_MASK) != 0) {
2656 			ctl_set_success(&io->scsiio);
2657 			ctl_config_write_done(io);
2658 			break;
2659 		}
2660 		if (cdb->how & SSS_START) {
2661 			if ((cdb->how & SSS_LOEJ) && be_lun->vn == NULL) {
2662 				retval = ctl_be_block_open(be_lun, &req);
2663 				cbe_lun->flags &= ~CTL_LUN_FLAG_EJECTED;
2664 				if (retval == 0) {
2665 					cbe_lun->flags &= ~CTL_LUN_FLAG_NO_MEDIA;
2666 					ctl_lun_has_media(cbe_lun);
2667 				} else {
2668 					cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2669 					ctl_lun_no_media(cbe_lun);
2670 				}
2671 			}
2672 			ctl_start_lun(cbe_lun);
2673 		} else {
2674 			ctl_stop_lun(cbe_lun);
2675 			if (cdb->how & SSS_LOEJ) {
2676 				cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2677 				cbe_lun->flags |= CTL_LUN_FLAG_EJECTED;
2678 				ctl_lun_ejected(cbe_lun);
2679 				if (be_lun->vn != NULL)
2680 					ctl_be_block_close(be_lun);
2681 			}
2682 		}
2683 
2684 		ctl_set_success(&io->scsiio);
2685 		ctl_config_write_done(io);
2686 		break;
2687 	}
2688 	case PREVENT_ALLOW:
2689 		ctl_set_success(&io->scsiio);
2690 		ctl_config_write_done(io);
2691 		break;
2692 	default:
2693 		ctl_set_invalid_opcode(&io->scsiio);
2694 		ctl_config_write_done(io);
2695 		retval = CTL_RETVAL_COMPLETE;
2696 		break;
2697 	}
2698 
2699 	return (retval);
2700 }
2701 
2702 static int
2703 ctl_be_block_config_read(union ctl_io *io)
2704 {
2705 	struct ctl_be_block_lun *be_lun;
2706 	int retval = 0;
2707 
2708 	DPRINTF("entered\n");
2709 
2710 	be_lun = (struct ctl_be_block_lun *)CTL_BACKEND_LUN(io);
2711 
2712 	switch (io->scsiio.cdb[0]) {
2713 	case SERVICE_ACTION_IN:
2714 		if (io->scsiio.cdb[1] == SGLS_SERVICE_ACTION) {
2715 			mtx_lock(&be_lun->queue_lock);
2716 			STAILQ_INSERT_TAIL(&be_lun->config_read_queue,
2717 			    &io->io_hdr, links);
2718 			mtx_unlock(&be_lun->queue_lock);
2719 			taskqueue_enqueue(be_lun->io_taskqueue,
2720 			    &be_lun->io_task);
2721 			retval = CTL_RETVAL_QUEUED;
2722 			break;
2723 		}
2724 		ctl_set_invalid_field(&io->scsiio,
2725 				      /*sks_valid*/ 1,
2726 				      /*command*/ 1,
2727 				      /*field*/ 1,
2728 				      /*bit_valid*/ 1,
2729 				      /*bit*/ 4);
2730 		ctl_config_read_done(io);
2731 		retval = CTL_RETVAL_COMPLETE;
2732 		break;
2733 	default:
2734 		ctl_set_invalid_opcode(&io->scsiio);
2735 		ctl_config_read_done(io);
2736 		retval = CTL_RETVAL_COMPLETE;
2737 		break;
2738 	}
2739 
2740 	return (retval);
2741 }
2742 
2743 static int
2744 ctl_be_block_lun_info(struct ctl_be_lun *cbe_lun, struct sbuf *sb)
2745 {
2746 	struct ctl_be_block_lun *lun = (struct ctl_be_block_lun *)cbe_lun;
2747 	int retval;
2748 
2749 	retval = sbuf_printf(sb, "\t<num_threads>");
2750 	if (retval != 0)
2751 		goto bailout;
2752 	retval = sbuf_printf(sb, "%d", lun->num_threads);
2753 	if (retval != 0)
2754 		goto bailout;
2755 	retval = sbuf_printf(sb, "</num_threads>\n");
2756 
2757 bailout:
2758 	return (retval);
2759 }
2760 
2761 static uint64_t
2762 ctl_be_block_lun_attr(struct ctl_be_lun *cbe_lun, const char *attrname)
2763 {
2764 	struct ctl_be_block_lun *lun = (struct ctl_be_block_lun *)cbe_lun;
2765 
2766 	if (lun->getattr == NULL)
2767 		return (UINT64_MAX);
2768 	return (lun->getattr(lun, attrname));
2769 }
2770 
2771 static int
2772 ctl_be_block_init(void)
2773 {
2774 	struct ctl_be_block_softc *softc = &backend_block_softc;
2775 
2776 	sx_init(&softc->modify_lock, "ctlblock modify");
2777 	mtx_init(&softc->lock, "ctlblock", NULL, MTX_DEF);
2778 	softc->beio_zone = uma_zcreate("beio", sizeof(struct ctl_be_block_io),
2779 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
2780 	softc->bufmin_zone = uma_zcreate("ctlblockmin", CTLBLK_MIN_SEG,
2781 	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
2782 	if (CTLBLK_MIN_SEG < CTLBLK_MAX_SEG)
2783 		softc->bufmax_zone = uma_zcreate("ctlblockmax", CTLBLK_MAX_SEG,
2784 		    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
2785 	SLIST_INIT(&softc->lun_list);
2786 	return (0);
2787 }
2788 
2789 static int
2790 ctl_be_block_shutdown(void)
2791 {
2792 	struct ctl_be_block_softc *softc = &backend_block_softc;
2793 	struct ctl_be_block_lun *lun;
2794 
2795 	mtx_lock(&softc->lock);
2796 	while ((lun = SLIST_FIRST(&softc->lun_list)) != NULL) {
2797 		SLIST_REMOVE_HEAD(&softc->lun_list, links);
2798 		softc->num_luns--;
2799 		/*
2800 		 * Drop our lock here.  Since ctl_remove_lun() can call
2801 		 * back into us, this could potentially lead to a recursive
2802 		 * lock of the same mutex, which would cause a hang.
2803 		 */
2804 		mtx_unlock(&softc->lock);
2805 		ctl_remove_lun(&lun->cbe_lun);
2806 		mtx_lock(&softc->lock);
2807 	}
2808 	mtx_unlock(&softc->lock);
2809 	uma_zdestroy(softc->bufmin_zone);
2810 	if (CTLBLK_MIN_SEG < CTLBLK_MAX_SEG)
2811 		uma_zdestroy(softc->bufmax_zone);
2812 	uma_zdestroy(softc->beio_zone);
2813 	mtx_destroy(&softc->lock);
2814 	sx_destroy(&softc->modify_lock);
2815 	return (0);
2816 }
2817