xref: /freebsd/sys/cam/ctl/ctl_backend_block.c (revision e17f5b1d)
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_MAX_SEG		MAXPHYS
106 #define	CTLBLK_HALF_SEGS	MAX(CTLBLK_HALF_IO_SIZE / CTLBLK_MAX_SEG, 1)
107 #define	CTLBLK_MAX_SEGS		(CTLBLK_HALF_SEGS * 2)
108 
109 #ifdef CTLBLK_DEBUG
110 #define DPRINTF(fmt, args...) \
111     printf("cbb(%s:%d): " fmt, __FUNCTION__, __LINE__, ##args)
112 #else
113 #define DPRINTF(fmt, args...) do {} while(0)
114 #endif
115 
116 #define PRIV(io)	\
117     ((struct ctl_ptr_len_flags *)&(io)->io_hdr.ctl_private[CTL_PRIV_BACKEND])
118 #define ARGS(io)	\
119     ((struct ctl_lba_len_flags *)&(io)->io_hdr.ctl_private[CTL_PRIV_LBA_LEN])
120 
121 SDT_PROVIDER_DEFINE(cbb);
122 
123 typedef enum {
124 	CTL_BE_BLOCK_LUN_UNCONFIGURED	= 0x01,
125 	CTL_BE_BLOCK_LUN_WAITING	= 0x04,
126 } ctl_be_block_lun_flags;
127 
128 typedef enum {
129 	CTL_BE_BLOCK_NONE,
130 	CTL_BE_BLOCK_DEV,
131 	CTL_BE_BLOCK_FILE
132 } ctl_be_block_type;
133 
134 struct ctl_be_block_filedata {
135 	struct ucred *cred;
136 };
137 
138 union ctl_be_block_bedata {
139 	struct ctl_be_block_filedata file;
140 };
141 
142 struct ctl_be_block_io;
143 struct ctl_be_block_lun;
144 
145 typedef void (*cbb_dispatch_t)(struct ctl_be_block_lun *be_lun,
146 			       struct ctl_be_block_io *beio);
147 typedef uint64_t (*cbb_getattr_t)(struct ctl_be_block_lun *be_lun,
148 				  const char *attrname);
149 
150 /*
151  * Backend LUN structure.  There is a 1:1 mapping between a block device
152  * and a backend block LUN, and between a backend block LUN and a CTL LUN.
153  */
154 struct ctl_be_block_lun {
155 	struct ctl_be_lun cbe_lun;		/* Must be first element. */
156 	struct ctl_lun_create_params params;
157 	char *dev_path;
158 	ctl_be_block_type dev_type;
159 	struct vnode *vn;
160 	union ctl_be_block_bedata backend;
161 	cbb_dispatch_t dispatch;
162 	cbb_dispatch_t lun_flush;
163 	cbb_dispatch_t unmap;
164 	cbb_dispatch_t get_lba_status;
165 	cbb_getattr_t getattr;
166 	uint64_t size_blocks;
167 	uint64_t size_bytes;
168 	struct ctl_be_block_softc *softc;
169 	struct devstat *disk_stats;
170 	ctl_be_block_lun_flags flags;
171 	SLIST_ENTRY(ctl_be_block_lun) links;
172 	struct taskqueue *io_taskqueue;
173 	struct task io_task;
174 	int num_threads;
175 	STAILQ_HEAD(, ctl_io_hdr) input_queue;
176 	STAILQ_HEAD(, ctl_io_hdr) config_read_queue;
177 	STAILQ_HEAD(, ctl_io_hdr) config_write_queue;
178 	STAILQ_HEAD(, ctl_io_hdr) datamove_queue;
179 	struct mtx_padalign io_lock;
180 	struct mtx_padalign queue_lock;
181 };
182 
183 /*
184  * Overall softc structure for the block backend module.
185  */
186 struct ctl_be_block_softc {
187 	struct sx			 modify_lock;
188 	struct mtx			 lock;
189 	int				 num_luns;
190 	SLIST_HEAD(, ctl_be_block_lun)	 lun_list;
191 	uma_zone_t			 beio_zone;
192 	uma_zone_t			 buf_zone;
193 };
194 
195 static struct ctl_be_block_softc backend_block_softc;
196 
197 /*
198  * Per-I/O information.
199  */
200 struct ctl_be_block_io {
201 	union ctl_io			*io;
202 	struct ctl_sg_entry		sg_segs[CTLBLK_MAX_SEGS];
203 	struct iovec			xiovecs[CTLBLK_MAX_SEGS];
204 	int				refcnt;
205 	int				bio_cmd;
206 	int				two_sglists;
207 	int				num_segs;
208 	int				num_bios_sent;
209 	int				num_bios_done;
210 	int				send_complete;
211 	int				first_error;
212 	uint64_t			first_error_offset;
213 	struct bintime			ds_t0;
214 	devstat_tag_type		ds_tag_type;
215 	devstat_trans_flags		ds_trans_type;
216 	uint64_t			io_len;
217 	uint64_t			io_offset;
218 	int				io_arg;
219 	struct ctl_be_block_softc	*softc;
220 	struct ctl_be_block_lun		*lun;
221 	void (*beio_cont)(struct ctl_be_block_io *beio); /* to continue processing */
222 };
223 
224 extern struct ctl_softc *control_softc;
225 
226 static int cbb_num_threads = 14;
227 SYSCTL_NODE(_kern_cam_ctl, OID_AUTO, block, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
228 	    "CAM Target Layer Block Backend");
229 SYSCTL_INT(_kern_cam_ctl_block, OID_AUTO, num_threads, CTLFLAG_RWTUN,
230            &cbb_num_threads, 0, "Number of threads per backing file");
231 
232 static struct ctl_be_block_io *ctl_alloc_beio(struct ctl_be_block_softc *softc);
233 static void ctl_free_beio(struct ctl_be_block_io *beio);
234 static void ctl_complete_beio(struct ctl_be_block_io *beio);
235 static int ctl_be_block_move_done(union ctl_io *io);
236 static void ctl_be_block_biodone(struct bio *bio);
237 static void ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
238 				    struct ctl_be_block_io *beio);
239 static void ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
240 				       struct ctl_be_block_io *beio);
241 static void ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
242 				  struct ctl_be_block_io *beio);
243 static uint64_t ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun,
244 					 const char *attrname);
245 static void ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
246 				   struct ctl_be_block_io *beio);
247 static void ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
248 				   struct ctl_be_block_io *beio);
249 static void ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
250 				      struct ctl_be_block_io *beio);
251 static uint64_t ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun,
252 					 const char *attrname);
253 static void ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
254 				    union ctl_io *io);
255 static void ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
256 				    union ctl_io *io);
257 static void ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
258 				  union ctl_io *io);
259 static void ctl_be_block_worker(void *context, int pending);
260 static int ctl_be_block_submit(union ctl_io *io);
261 static int ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
262 				   int flag, struct thread *td);
263 static int ctl_be_block_open_file(struct ctl_be_block_lun *be_lun,
264 				  struct ctl_lun_req *req);
265 static int ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun,
266 				 struct ctl_lun_req *req);
267 static int ctl_be_block_close(struct ctl_be_block_lun *be_lun);
268 static int ctl_be_block_open(struct ctl_be_block_lun *be_lun,
269 			     struct ctl_lun_req *req);
270 static int ctl_be_block_create(struct ctl_be_block_softc *softc,
271 			       struct ctl_lun_req *req);
272 static int ctl_be_block_rm(struct ctl_be_block_softc *softc,
273 			   struct ctl_lun_req *req);
274 static int ctl_be_block_modify(struct ctl_be_block_softc *softc,
275 			   struct ctl_lun_req *req);
276 static void ctl_be_block_lun_shutdown(struct ctl_be_lun *cbe_lun);
277 static int ctl_be_block_config_write(union ctl_io *io);
278 static int ctl_be_block_config_read(union ctl_io *io);
279 static int ctl_be_block_lun_info(struct ctl_be_lun *cbe_lun, struct sbuf *sb);
280 static uint64_t ctl_be_block_lun_attr(struct ctl_be_lun *cbe_lun, const char *attrname);
281 static int ctl_be_block_init(void);
282 static int ctl_be_block_shutdown(void);
283 
284 static struct ctl_backend_driver ctl_be_block_driver =
285 {
286 	.name = "block",
287 	.flags = CTL_BE_FLAG_HAS_CONFIG,
288 	.init = ctl_be_block_init,
289 	.shutdown = ctl_be_block_shutdown,
290 	.data_submit = ctl_be_block_submit,
291 	.data_move_done = ctl_be_block_move_done,
292 	.config_read = ctl_be_block_config_read,
293 	.config_write = ctl_be_block_config_write,
294 	.ioctl = ctl_be_block_ioctl,
295 	.lun_info = ctl_be_block_lun_info,
296 	.lun_attr = ctl_be_block_lun_attr
297 };
298 
299 MALLOC_DEFINE(M_CTLBLK, "ctlblock", "Memory used for CTL block backend");
300 CTL_BACKEND_DECLARE(cbb, ctl_be_block_driver);
301 
302 static struct ctl_be_block_io *
303 ctl_alloc_beio(struct ctl_be_block_softc *softc)
304 {
305 	struct ctl_be_block_io *beio;
306 
307 	beio = uma_zalloc(softc->beio_zone, M_WAITOK | M_ZERO);
308 	beio->softc = softc;
309 	beio->refcnt = 1;
310 	return (beio);
311 }
312 
313 static void
314 ctl_real_free_beio(struct ctl_be_block_io *beio)
315 {
316 	struct ctl_be_block_softc *softc = beio->softc;
317 	int i;
318 
319 	for (i = 0; i < beio->num_segs; i++) {
320 		uma_zfree(softc->buf_zone, beio->sg_segs[i].addr);
321 
322 		/* For compare we had two equal S/G lists. */
323 		if (beio->two_sglists) {
324 			uma_zfree(softc->buf_zone,
325 			    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr);
326 		}
327 	}
328 
329 	uma_zfree(softc->beio_zone, beio);
330 }
331 
332 static void
333 ctl_refcnt_beio(void *arg, int diff)
334 {
335 	struct ctl_be_block_io *beio = arg;
336 
337 	if (atomic_fetchadd_int(&beio->refcnt, diff) + diff == 0)
338 		ctl_real_free_beio(beio);
339 }
340 
341 static void
342 ctl_free_beio(struct ctl_be_block_io *beio)
343 {
344 
345 	ctl_refcnt_beio(beio, -1);
346 }
347 
348 static void
349 ctl_complete_beio(struct ctl_be_block_io *beio)
350 {
351 	union ctl_io *io = beio->io;
352 
353 	if (beio->beio_cont != NULL) {
354 		beio->beio_cont(beio);
355 	} else {
356 		ctl_free_beio(beio);
357 		ctl_data_submit_done(io);
358 	}
359 }
360 
361 static size_t
362 cmp(uint8_t *a, uint8_t *b, size_t size)
363 {
364 	size_t i;
365 
366 	for (i = 0; i < size; i++) {
367 		if (a[i] != b[i])
368 			break;
369 	}
370 	return (i);
371 }
372 
373 static void
374 ctl_be_block_compare(union ctl_io *io)
375 {
376 	struct ctl_be_block_io *beio;
377 	uint64_t off, res;
378 	int i;
379 	uint8_t info[8];
380 
381 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
382 	off = 0;
383 	for (i = 0; i < beio->num_segs; i++) {
384 		res = cmp(beio->sg_segs[i].addr,
385 		    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr,
386 		    beio->sg_segs[i].len);
387 		off += res;
388 		if (res < beio->sg_segs[i].len)
389 			break;
390 	}
391 	if (i < beio->num_segs) {
392 		scsi_u64to8b(off, info);
393 		ctl_set_sense(&io->scsiio, /*current_error*/ 1,
394 		    /*sense_key*/ SSD_KEY_MISCOMPARE,
395 		    /*asc*/ 0x1D, /*ascq*/ 0x00,
396 		    /*type*/ SSD_ELEM_INFO,
397 		    /*size*/ sizeof(info), /*data*/ &info,
398 		    /*type*/ SSD_ELEM_NONE);
399 	} else
400 		ctl_set_success(&io->scsiio);
401 }
402 
403 static int
404 ctl_be_block_move_done(union ctl_io *io)
405 {
406 	struct ctl_be_block_io *beio;
407 	struct ctl_be_block_lun *be_lun;
408 	struct ctl_lba_len_flags *lbalen;
409 #ifdef CTL_TIME_IO
410 	struct bintime cur_bt;
411 #endif
412 
413 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
414 	be_lun = beio->lun;
415 
416 	DPRINTF("entered\n");
417 
418 #ifdef CTL_TIME_IO
419 	getbinuptime(&cur_bt);
420 	bintime_sub(&cur_bt, &io->io_hdr.dma_start_bt);
421 	bintime_add(&io->io_hdr.dma_bt, &cur_bt);
422 #endif
423 	io->io_hdr.num_dmas++;
424 	io->scsiio.kern_rel_offset += io->scsiio.kern_data_len;
425 
426 	/*
427 	 * We set status at this point for read commands, and write
428 	 * commands with errors.
429 	 */
430 	if (io->io_hdr.flags & CTL_FLAG_ABORT) {
431 		;
432 	} else if ((io->io_hdr.port_status != 0) &&
433 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE ||
434 	     (io->io_hdr.status & CTL_STATUS_MASK) == CTL_SUCCESS)) {
435 		ctl_set_internal_failure(&io->scsiio, /*sks_valid*/ 1,
436 		    /*retry_count*/ io->io_hdr.port_status);
437 	} else if (io->scsiio.kern_data_resid != 0 &&
438 	    (io->io_hdr.flags & CTL_FLAG_DATA_MASK) == CTL_FLAG_DATA_OUT &&
439 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE ||
440 	     (io->io_hdr.status & CTL_STATUS_MASK) == CTL_SUCCESS)) {
441 		ctl_set_invalid_field_ciu(&io->scsiio);
442 	} else if ((io->io_hdr.port_status == 0) &&
443 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE)) {
444 		lbalen = ARGS(beio->io);
445 		if (lbalen->flags & CTL_LLF_READ) {
446 			ctl_set_success(&io->scsiio);
447 		} else if (lbalen->flags & CTL_LLF_COMPARE) {
448 			/* We have two data blocks ready for comparison. */
449 			ctl_be_block_compare(io);
450 		}
451 	}
452 
453 	/*
454 	 * If this is a read, or a write with errors, it is done.
455 	 */
456 	if ((beio->bio_cmd == BIO_READ)
457 	 || ((io->io_hdr.flags & CTL_FLAG_ABORT) != 0)
458 	 || ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE)) {
459 		ctl_complete_beio(beio);
460 		return (0);
461 	}
462 
463 	/*
464 	 * At this point, we have a write and the DMA completed
465 	 * successfully.  We now have to queue it to the task queue to
466 	 * execute the backend I/O.  That is because we do blocking
467 	 * memory allocations, and in the file backing case, blocking I/O.
468 	 * This move done routine is generally called in the SIM's
469 	 * interrupt context, and therefore we cannot block.
470 	 */
471 	mtx_lock(&be_lun->queue_lock);
472 	STAILQ_INSERT_TAIL(&be_lun->datamove_queue, &io->io_hdr, links);
473 	mtx_unlock(&be_lun->queue_lock);
474 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
475 
476 	return (0);
477 }
478 
479 static void
480 ctl_be_block_biodone(struct bio *bio)
481 {
482 	struct ctl_be_block_io *beio;
483 	struct ctl_be_block_lun *be_lun;
484 	union ctl_io *io;
485 	int error;
486 
487 	beio = bio->bio_caller1;
488 	be_lun = beio->lun;
489 	io = beio->io;
490 
491 	DPRINTF("entered\n");
492 
493 	error = bio->bio_error;
494 	mtx_lock(&be_lun->io_lock);
495 	if (error != 0 &&
496 	    (beio->first_error == 0 ||
497 	     bio->bio_offset < beio->first_error_offset)) {
498 		beio->first_error = error;
499 		beio->first_error_offset = bio->bio_offset;
500 	}
501 
502 	beio->num_bios_done++;
503 
504 	/*
505 	 * XXX KDM will this cause WITNESS to complain?  Holding a lock
506 	 * during the free might cause it to complain.
507 	 */
508 	g_destroy_bio(bio);
509 
510 	/*
511 	 * If the send complete bit isn't set, or we aren't the last I/O to
512 	 * complete, then we're done.
513 	 */
514 	if ((beio->send_complete == 0)
515 	 || (beio->num_bios_done < beio->num_bios_sent)) {
516 		mtx_unlock(&be_lun->io_lock);
517 		return;
518 	}
519 
520 	/*
521 	 * At this point, we've verified that we are the last I/O to
522 	 * complete, so it's safe to drop the lock.
523 	 */
524 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
525 	    beio->ds_tag_type, beio->ds_trans_type,
526 	    /*now*/ NULL, /*then*/&beio->ds_t0);
527 	mtx_unlock(&be_lun->io_lock);
528 
529 	/*
530 	 * If there are any errors from the backing device, we fail the
531 	 * entire I/O with a medium error.
532 	 */
533 	error = beio->first_error;
534 	if (error != 0) {
535 		if (error == EOPNOTSUPP) {
536 			ctl_set_invalid_opcode(&io->scsiio);
537 		} else if (error == ENOSPC || error == EDQUOT) {
538 			ctl_set_space_alloc_fail(&io->scsiio);
539 		} else if (error == EROFS || error == EACCES) {
540 			ctl_set_hw_write_protected(&io->scsiio);
541 		} else if (beio->bio_cmd == BIO_FLUSH) {
542 			/* XXX KDM is there is a better error here? */
543 			ctl_set_internal_failure(&io->scsiio,
544 						 /*sks_valid*/ 1,
545 						 /*retry_count*/ 0xbad2);
546 		} else {
547 			ctl_set_medium_error(&io->scsiio,
548 			    beio->bio_cmd == BIO_READ);
549 		}
550 		ctl_complete_beio(beio);
551 		return;
552 	}
553 
554 	/*
555 	 * If this is a write, a flush, a delete or verify, we're all done.
556 	 * If this is a read, we can now send the data to the user.
557 	 */
558 	if ((beio->bio_cmd == BIO_WRITE)
559 	 || (beio->bio_cmd == BIO_FLUSH)
560 	 || (beio->bio_cmd == BIO_DELETE)
561 	 || (ARGS(io)->flags & CTL_LLF_VERIFY)) {
562 		ctl_set_success(&io->scsiio);
563 		ctl_complete_beio(beio);
564 	} else {
565 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
566 		    beio->beio_cont == NULL) {
567 			ctl_set_success(&io->scsiio);
568 			ctl_serseq_done(io);
569 		}
570 #ifdef CTL_TIME_IO
571 		getbinuptime(&io->io_hdr.dma_start_bt);
572 #endif
573 		ctl_datamove(io);
574 	}
575 }
576 
577 static void
578 ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
579 			struct ctl_be_block_io *beio)
580 {
581 	union ctl_io *io = beio->io;
582 	struct mount *mountpoint;
583 	int error, lock_flags;
584 
585 	DPRINTF("entered\n");
586 
587 	binuptime(&beio->ds_t0);
588 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
589 
590 	(void) vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
591 
592 	if (MNT_SHARED_WRITES(mountpoint) ||
593 	    ((mountpoint == NULL) && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
594 		lock_flags = LK_SHARED;
595 	else
596 		lock_flags = LK_EXCLUSIVE;
597 	vn_lock(be_lun->vn, lock_flags | LK_RETRY);
598 	error = VOP_FSYNC(be_lun->vn, beio->io_arg ? MNT_NOWAIT : MNT_WAIT,
599 	    curthread);
600 	VOP_UNLOCK(be_lun->vn);
601 
602 	vn_finished_write(mountpoint);
603 
604 	mtx_lock(&be_lun->io_lock);
605 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
606 	    beio->ds_tag_type, beio->ds_trans_type,
607 	    /*now*/ NULL, /*then*/&beio->ds_t0);
608 	mtx_unlock(&be_lun->io_lock);
609 
610 	if (error == 0)
611 		ctl_set_success(&io->scsiio);
612 	else {
613 		/* XXX KDM is there is a better error here? */
614 		ctl_set_internal_failure(&io->scsiio,
615 					 /*sks_valid*/ 1,
616 					 /*retry_count*/ 0xbad1);
617 	}
618 
619 	ctl_complete_beio(beio);
620 }
621 
622 SDT_PROBE_DEFINE1(cbb, , read, file_start, "uint64_t");
623 SDT_PROBE_DEFINE1(cbb, , write, file_start, "uint64_t");
624 SDT_PROBE_DEFINE1(cbb, , read, file_done,"uint64_t");
625 SDT_PROBE_DEFINE1(cbb, , write, file_done, "uint64_t");
626 
627 static void
628 ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
629 			   struct ctl_be_block_io *beio)
630 {
631 	struct ctl_be_block_filedata *file_data;
632 	union ctl_io *io;
633 	struct uio xuio;
634 	struct iovec *xiovec;
635 	size_t s;
636 	int error, flags, i;
637 
638 	DPRINTF("entered\n");
639 
640 	file_data = &be_lun->backend.file;
641 	io = beio->io;
642 	flags = 0;
643 	if (ARGS(io)->flags & CTL_LLF_DPO)
644 		flags |= IO_DIRECT;
645 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
646 		flags |= IO_SYNC;
647 
648 	bzero(&xuio, sizeof(xuio));
649 	if (beio->bio_cmd == BIO_READ) {
650 		SDT_PROBE0(cbb, , read, file_start);
651 		xuio.uio_rw = UIO_READ;
652 	} else {
653 		SDT_PROBE0(cbb, , write, file_start);
654 		xuio.uio_rw = UIO_WRITE;
655 	}
656 	xuio.uio_offset = beio->io_offset;
657 	xuio.uio_resid = beio->io_len;
658 	xuio.uio_segflg = UIO_SYSSPACE;
659 	xuio.uio_iov = beio->xiovecs;
660 	xuio.uio_iovcnt = beio->num_segs;
661 	xuio.uio_td = curthread;
662 
663 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
664 		xiovec->iov_base = beio->sg_segs[i].addr;
665 		xiovec->iov_len = beio->sg_segs[i].len;
666 	}
667 
668 	binuptime(&beio->ds_t0);
669 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
670 
671 	if (beio->bio_cmd == BIO_READ) {
672 		vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
673 
674 		/*
675 		 * UFS pays attention to IO_DIRECT for reads.  If the
676 		 * DIRECTIO option is configured into the kernel, it calls
677 		 * ffs_rawread().  But that only works for single-segment
678 		 * uios with user space addresses.  In our case, with a
679 		 * kernel uio, it still reads into the buffer cache, but it
680 		 * will just try to release the buffer from the cache later
681 		 * on in ffs_read().
682 		 *
683 		 * ZFS does not pay attention to IO_DIRECT for reads.
684 		 *
685 		 * UFS does not pay attention to IO_SYNC for reads.
686 		 *
687 		 * ZFS pays attention to IO_SYNC (which translates into the
688 		 * Solaris define FRSYNC for zfs_read()) for reads.  It
689 		 * attempts to sync the file before reading.
690 		 */
691 		error = VOP_READ(be_lun->vn, &xuio, flags, file_data->cred);
692 
693 		VOP_UNLOCK(be_lun->vn);
694 		SDT_PROBE0(cbb, , read, file_done);
695 		if (error == 0 && xuio.uio_resid > 0) {
696 			/*
697 			 * If we red less then requested (EOF), then
698 			 * we should clean the rest of the buffer.
699 			 */
700 			s = beio->io_len - xuio.uio_resid;
701 			for (i = 0; i < beio->num_segs; i++) {
702 				if (s >= beio->sg_segs[i].len) {
703 					s -= beio->sg_segs[i].len;
704 					continue;
705 				}
706 				bzero((uint8_t *)beio->sg_segs[i].addr + s,
707 				    beio->sg_segs[i].len - s);
708 				s = 0;
709 			}
710 		}
711 	} else {
712 		struct mount *mountpoint;
713 		int lock_flags;
714 
715 		(void)vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
716 
717 		if (MNT_SHARED_WRITES(mountpoint) || ((mountpoint == NULL)
718 		  && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
719 			lock_flags = LK_SHARED;
720 		else
721 			lock_flags = LK_EXCLUSIVE;
722 		vn_lock(be_lun->vn, lock_flags | LK_RETRY);
723 
724 		/*
725 		 * UFS pays attention to IO_DIRECT for writes.  The write
726 		 * is done asynchronously.  (Normally the write would just
727 		 * get put into cache.
728 		 *
729 		 * UFS pays attention to IO_SYNC for writes.  It will
730 		 * attempt to write the buffer out synchronously if that
731 		 * flag is set.
732 		 *
733 		 * ZFS does not pay attention to IO_DIRECT for writes.
734 		 *
735 		 * ZFS pays attention to IO_SYNC (a.k.a. FSYNC or FRSYNC)
736 		 * for writes.  It will flush the transaction from the
737 		 * cache before returning.
738 		 */
739 		error = VOP_WRITE(be_lun->vn, &xuio, flags, file_data->cred);
740 		VOP_UNLOCK(be_lun->vn);
741 
742 		vn_finished_write(mountpoint);
743 		SDT_PROBE0(cbb, , write, file_done);
744         }
745 
746 	mtx_lock(&be_lun->io_lock);
747 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
748 	    beio->ds_tag_type, beio->ds_trans_type,
749 	    /*now*/ NULL, /*then*/&beio->ds_t0);
750 	mtx_unlock(&be_lun->io_lock);
751 
752 	/*
753 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
754 	 * return the I/O to the user.
755 	 */
756 	if (error != 0) {
757 		if (error == ENOSPC || error == EDQUOT) {
758 			ctl_set_space_alloc_fail(&io->scsiio);
759 		} else if (error == EROFS || error == EACCES) {
760 			ctl_set_hw_write_protected(&io->scsiio);
761 		} else {
762 			ctl_set_medium_error(&io->scsiio,
763 			    beio->bio_cmd == BIO_READ);
764 		}
765 		ctl_complete_beio(beio);
766 		return;
767 	}
768 
769 	/*
770 	 * If this is a write or a verify, we're all done.
771 	 * If this is a read, we can now send the data to the user.
772 	 */
773 	if ((beio->bio_cmd == BIO_WRITE) ||
774 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
775 		ctl_set_success(&io->scsiio);
776 		ctl_complete_beio(beio);
777 	} else {
778 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
779 		    beio->beio_cont == NULL) {
780 			ctl_set_success(&io->scsiio);
781 			ctl_serseq_done(io);
782 		}
783 #ifdef CTL_TIME_IO
784 		getbinuptime(&io->io_hdr.dma_start_bt);
785 #endif
786 		ctl_datamove(io);
787 	}
788 }
789 
790 static void
791 ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
792 			struct ctl_be_block_io *beio)
793 {
794 	union ctl_io *io = beio->io;
795 	struct ctl_lba_len_flags *lbalen = ARGS(io);
796 	struct scsi_get_lba_status_data *data;
797 	off_t roff, off;
798 	int error, status;
799 
800 	DPRINTF("entered\n");
801 
802 	off = roff = ((off_t)lbalen->lba) * be_lun->cbe_lun.blocksize;
803 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
804 	error = VOP_IOCTL(be_lun->vn, FIOSEEKHOLE, &off,
805 	    0, curthread->td_ucred, curthread);
806 	if (error == 0 && off > roff)
807 		status = 0;	/* mapped up to off */
808 	else {
809 		error = VOP_IOCTL(be_lun->vn, FIOSEEKDATA, &off,
810 		    0, curthread->td_ucred, curthread);
811 		if (error == 0 && off > roff)
812 			status = 1;	/* deallocated up to off */
813 		else {
814 			status = 0;	/* unknown up to the end */
815 			off = be_lun->size_bytes;
816 		}
817 	}
818 	VOP_UNLOCK(be_lun->vn);
819 
820 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
821 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
822 	scsi_ulto4b(MIN(UINT32_MAX, off / be_lun->cbe_lun.blocksize -
823 	    lbalen->lba), data->descr[0].length);
824 	data->descr[0].status = status;
825 
826 	ctl_complete_beio(beio);
827 }
828 
829 static uint64_t
830 ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun, const char *attrname)
831 {
832 	struct vattr		vattr;
833 	struct statfs		statfs;
834 	uint64_t		val;
835 	int			error;
836 
837 	val = UINT64_MAX;
838 	if (be_lun->vn == NULL)
839 		return (val);
840 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
841 	if (strcmp(attrname, "blocksused") == 0) {
842 		error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
843 		if (error == 0)
844 			val = vattr.va_bytes / be_lun->cbe_lun.blocksize;
845 	}
846 	if (strcmp(attrname, "blocksavail") == 0 &&
847 	    !VN_IS_DOOMED(be_lun->vn)) {
848 		error = VFS_STATFS(be_lun->vn->v_mount, &statfs);
849 		if (error == 0)
850 			val = statfs.f_bavail * statfs.f_bsize /
851 			    be_lun->cbe_lun.blocksize;
852 	}
853 	VOP_UNLOCK(be_lun->vn);
854 	return (val);
855 }
856 
857 static void
858 ctl_be_block_dispatch_zvol(struct ctl_be_block_lun *be_lun,
859 			   struct ctl_be_block_io *beio)
860 {
861 	union ctl_io *io;
862 	struct cdevsw *csw;
863 	struct cdev *dev;
864 	struct uio xuio;
865 	struct iovec *xiovec;
866 	int error, flags, i, ref;
867 
868 	DPRINTF("entered\n");
869 
870 	io = beio->io;
871 	flags = 0;
872 	if (ARGS(io)->flags & CTL_LLF_DPO)
873 		flags |= IO_DIRECT;
874 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
875 		flags |= IO_SYNC;
876 
877 	bzero(&xuio, sizeof(xuio));
878 	if (beio->bio_cmd == BIO_READ) {
879 		SDT_PROBE0(cbb, , read, file_start);
880 		xuio.uio_rw = UIO_READ;
881 	} else {
882 		SDT_PROBE0(cbb, , write, file_start);
883 		xuio.uio_rw = UIO_WRITE;
884 	}
885 	xuio.uio_offset = beio->io_offset;
886 	xuio.uio_resid = beio->io_len;
887 	xuio.uio_segflg = UIO_SYSSPACE;
888 	xuio.uio_iov = beio->xiovecs;
889 	xuio.uio_iovcnt = beio->num_segs;
890 	xuio.uio_td = curthread;
891 
892 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
893 		xiovec->iov_base = beio->sg_segs[i].addr;
894 		xiovec->iov_len = beio->sg_segs[i].len;
895 	}
896 
897 	binuptime(&beio->ds_t0);
898 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
899 
900 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
901 	if (csw) {
902 		if (beio->bio_cmd == BIO_READ)
903 			error = csw->d_read(dev, &xuio, flags);
904 		else
905 			error = csw->d_write(dev, &xuio, flags);
906 		dev_relthread(dev, ref);
907 	} else
908 		error = ENXIO;
909 
910 	if (beio->bio_cmd == BIO_READ)
911 		SDT_PROBE0(cbb, , read, file_done);
912 	else
913 		SDT_PROBE0(cbb, , write, file_done);
914 
915 	mtx_lock(&be_lun->io_lock);
916 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
917 	    beio->ds_tag_type, beio->ds_trans_type,
918 	    /*now*/ NULL, /*then*/&beio->ds_t0);
919 	mtx_unlock(&be_lun->io_lock);
920 
921 	/*
922 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
923 	 * return the I/O to the user.
924 	 */
925 	if (error != 0) {
926 		if (error == ENOSPC || error == EDQUOT) {
927 			ctl_set_space_alloc_fail(&io->scsiio);
928 		} else if (error == EROFS || error == EACCES) {
929 			ctl_set_hw_write_protected(&io->scsiio);
930 		} else {
931 			ctl_set_medium_error(&io->scsiio,
932 			    beio->bio_cmd == BIO_READ);
933 		}
934 		ctl_complete_beio(beio);
935 		return;
936 	}
937 
938 	/*
939 	 * If this is a write or a verify, we're all done.
940 	 * If this is a read, we can now send the data to the user.
941 	 */
942 	if ((beio->bio_cmd == BIO_WRITE) ||
943 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
944 		ctl_set_success(&io->scsiio);
945 		ctl_complete_beio(beio);
946 	} else {
947 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
948 		    beio->beio_cont == NULL) {
949 			ctl_set_success(&io->scsiio);
950 			ctl_serseq_done(io);
951 		}
952 #ifdef CTL_TIME_IO
953 		getbinuptime(&io->io_hdr.dma_start_bt);
954 #endif
955 		ctl_datamove(io);
956 	}
957 }
958 
959 static void
960 ctl_be_block_gls_zvol(struct ctl_be_block_lun *be_lun,
961 			struct ctl_be_block_io *beio)
962 {
963 	union ctl_io *io = beio->io;
964 	struct cdevsw *csw;
965 	struct cdev *dev;
966 	struct ctl_lba_len_flags *lbalen = ARGS(io);
967 	struct scsi_get_lba_status_data *data;
968 	off_t roff, off;
969 	int error, ref, status;
970 
971 	DPRINTF("entered\n");
972 
973 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
974 	if (csw == NULL) {
975 		status = 0;	/* unknown up to the end */
976 		off = be_lun->size_bytes;
977 		goto done;
978 	}
979 	off = roff = ((off_t)lbalen->lba) * be_lun->cbe_lun.blocksize;
980 	error = csw->d_ioctl(dev, FIOSEEKHOLE, (caddr_t)&off, FREAD,
981 	    curthread);
982 	if (error == 0 && off > roff)
983 		status = 0;	/* mapped up to off */
984 	else {
985 		error = csw->d_ioctl(dev, FIOSEEKDATA, (caddr_t)&off, FREAD,
986 		    curthread);
987 		if (error == 0 && off > roff)
988 			status = 1;	/* deallocated up to off */
989 		else {
990 			status = 0;	/* unknown up to the end */
991 			off = be_lun->size_bytes;
992 		}
993 	}
994 	dev_relthread(dev, ref);
995 
996 done:
997 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
998 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
999 	scsi_ulto4b(MIN(UINT32_MAX, off / be_lun->cbe_lun.blocksize -
1000 	    lbalen->lba), data->descr[0].length);
1001 	data->descr[0].status = status;
1002 
1003 	ctl_complete_beio(beio);
1004 }
1005 
1006 static void
1007 ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
1008 		       struct ctl_be_block_io *beio)
1009 {
1010 	struct bio *bio;
1011 	struct cdevsw *csw;
1012 	struct cdev *dev;
1013 	int ref;
1014 
1015 	DPRINTF("entered\n");
1016 
1017 	/* This can't fail, it's a blocking allocation. */
1018 	bio = g_alloc_bio();
1019 
1020 	bio->bio_cmd	    = BIO_FLUSH;
1021 	bio->bio_offset	    = 0;
1022 	bio->bio_data	    = 0;
1023 	bio->bio_done	    = ctl_be_block_biodone;
1024 	bio->bio_caller1    = beio;
1025 	bio->bio_pblkno	    = 0;
1026 
1027 	/*
1028 	 * We don't need to acquire the LUN lock here, because we are only
1029 	 * sending one bio, and so there is no other context to synchronize
1030 	 * with.
1031 	 */
1032 	beio->num_bios_sent = 1;
1033 	beio->send_complete = 1;
1034 
1035 	binuptime(&beio->ds_t0);
1036 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1037 
1038 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1039 	if (csw) {
1040 		bio->bio_dev = dev;
1041 		csw->d_strategy(bio);
1042 		dev_relthread(dev, ref);
1043 	} else {
1044 		bio->bio_error = ENXIO;
1045 		ctl_be_block_biodone(bio);
1046 	}
1047 }
1048 
1049 static void
1050 ctl_be_block_unmap_dev_range(struct ctl_be_block_lun *be_lun,
1051 		       struct ctl_be_block_io *beio,
1052 		       uint64_t off, uint64_t len, int last)
1053 {
1054 	struct bio *bio;
1055 	uint64_t maxlen;
1056 	struct cdevsw *csw;
1057 	struct cdev *dev;
1058 	int ref;
1059 
1060 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1061 	maxlen = LONG_MAX - (LONG_MAX % be_lun->cbe_lun.blocksize);
1062 	while (len > 0) {
1063 		bio = g_alloc_bio();
1064 		bio->bio_cmd	    = BIO_DELETE;
1065 		bio->bio_dev	    = dev;
1066 		bio->bio_offset	    = off;
1067 		bio->bio_length	    = MIN(len, maxlen);
1068 		bio->bio_data	    = 0;
1069 		bio->bio_done	    = ctl_be_block_biodone;
1070 		bio->bio_caller1    = beio;
1071 		bio->bio_pblkno     = off / be_lun->cbe_lun.blocksize;
1072 
1073 		off += bio->bio_length;
1074 		len -= bio->bio_length;
1075 
1076 		mtx_lock(&be_lun->io_lock);
1077 		beio->num_bios_sent++;
1078 		if (last && len == 0)
1079 			beio->send_complete = 1;
1080 		mtx_unlock(&be_lun->io_lock);
1081 
1082 		if (csw) {
1083 			csw->d_strategy(bio);
1084 		} else {
1085 			bio->bio_error = ENXIO;
1086 			ctl_be_block_biodone(bio);
1087 		}
1088 	}
1089 	if (csw)
1090 		dev_relthread(dev, ref);
1091 }
1092 
1093 static void
1094 ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
1095 		       struct ctl_be_block_io *beio)
1096 {
1097 	union ctl_io *io;
1098 	struct ctl_ptr_len_flags *ptrlen;
1099 	struct scsi_unmap_desc *buf, *end;
1100 	uint64_t len;
1101 
1102 	io = beio->io;
1103 
1104 	DPRINTF("entered\n");
1105 
1106 	binuptime(&beio->ds_t0);
1107 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1108 
1109 	if (beio->io_offset == -1) {
1110 		beio->io_len = 0;
1111 		ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1112 		buf = (struct scsi_unmap_desc *)ptrlen->ptr;
1113 		end = buf + ptrlen->len / sizeof(*buf);
1114 		for (; buf < end; buf++) {
1115 			len = (uint64_t)scsi_4btoul(buf->length) *
1116 			    be_lun->cbe_lun.blocksize;
1117 			beio->io_len += len;
1118 			ctl_be_block_unmap_dev_range(be_lun, beio,
1119 			    scsi_8btou64(buf->lba) * be_lun->cbe_lun.blocksize,
1120 			    len, (end - buf < 2) ? TRUE : FALSE);
1121 		}
1122 	} else
1123 		ctl_be_block_unmap_dev_range(be_lun, beio,
1124 		    beio->io_offset, beio->io_len, TRUE);
1125 }
1126 
1127 static void
1128 ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
1129 			  struct ctl_be_block_io *beio)
1130 {
1131 	TAILQ_HEAD(, bio) queue = TAILQ_HEAD_INITIALIZER(queue);
1132 	struct bio *bio;
1133 	struct cdevsw *csw;
1134 	struct cdev *dev;
1135 	off_t cur_offset;
1136 	int i, max_iosize, ref;
1137 
1138 	DPRINTF("entered\n");
1139 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1140 
1141 	/*
1142 	 * We have to limit our I/O size to the maximum supported by the
1143 	 * backend device.  Hopefully it is MAXPHYS.  If the driver doesn't
1144 	 * set it properly, use DFLTPHYS.
1145 	 */
1146 	if (csw) {
1147 		max_iosize = dev->si_iosize_max;
1148 		if (max_iosize < PAGE_SIZE)
1149 			max_iosize = DFLTPHYS;
1150 	} else
1151 		max_iosize = DFLTPHYS;
1152 
1153 	cur_offset = beio->io_offset;
1154 	for (i = 0; i < beio->num_segs; i++) {
1155 		size_t cur_size;
1156 		uint8_t *cur_ptr;
1157 
1158 		cur_size = beio->sg_segs[i].len;
1159 		cur_ptr = beio->sg_segs[i].addr;
1160 
1161 		while (cur_size > 0) {
1162 			/* This can't fail, it's a blocking allocation. */
1163 			bio = g_alloc_bio();
1164 
1165 			KASSERT(bio != NULL, ("g_alloc_bio() failed!\n"));
1166 
1167 			bio->bio_cmd = beio->bio_cmd;
1168 			bio->bio_dev = dev;
1169 			bio->bio_caller1 = beio;
1170 			bio->bio_length = min(cur_size, max_iosize);
1171 			bio->bio_offset = cur_offset;
1172 			bio->bio_data = cur_ptr;
1173 			bio->bio_done = ctl_be_block_biodone;
1174 			bio->bio_pblkno = cur_offset / be_lun->cbe_lun.blocksize;
1175 
1176 			cur_offset += bio->bio_length;
1177 			cur_ptr += bio->bio_length;
1178 			cur_size -= bio->bio_length;
1179 
1180 			TAILQ_INSERT_TAIL(&queue, bio, bio_queue);
1181 			beio->num_bios_sent++;
1182 		}
1183 	}
1184 	beio->send_complete = 1;
1185 	binuptime(&beio->ds_t0);
1186 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1187 
1188 	/*
1189 	 * Fire off all allocated requests!
1190 	 */
1191 	while ((bio = TAILQ_FIRST(&queue)) != NULL) {
1192 		TAILQ_REMOVE(&queue, bio, bio_queue);
1193 		if (csw)
1194 			csw->d_strategy(bio);
1195 		else {
1196 			bio->bio_error = ENXIO;
1197 			ctl_be_block_biodone(bio);
1198 		}
1199 	}
1200 	if (csw)
1201 		dev_relthread(dev, ref);
1202 }
1203 
1204 static uint64_t
1205 ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun, const char *attrname)
1206 {
1207 	struct diocgattr_arg	arg;
1208 	struct cdevsw *csw;
1209 	struct cdev *dev;
1210 	int error, ref;
1211 
1212 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1213 	if (csw == NULL)
1214 		return (UINT64_MAX);
1215 	strlcpy(arg.name, attrname, sizeof(arg.name));
1216 	arg.len = sizeof(arg.value.off);
1217 	if (csw->d_ioctl) {
1218 		error = csw->d_ioctl(dev, DIOCGATTR, (caddr_t)&arg, FREAD,
1219 		    curthread);
1220 	} else
1221 		error = ENODEV;
1222 	dev_relthread(dev, ref);
1223 	if (error != 0)
1224 		return (UINT64_MAX);
1225 	return (arg.value.off);
1226 }
1227 
1228 static void
1229 ctl_be_block_cw_dispatch_sync(struct ctl_be_block_lun *be_lun,
1230 			    union ctl_io *io)
1231 {
1232 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1233 	struct ctl_be_block_io *beio;
1234 	struct ctl_lba_len_flags *lbalen;
1235 
1236 	DPRINTF("entered\n");
1237 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1238 	lbalen = (struct ctl_lba_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1239 
1240 	beio->io_len = lbalen->len * cbe_lun->blocksize;
1241 	beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1242 	beio->io_arg = (lbalen->flags & SSC_IMMED) != 0;
1243 	beio->bio_cmd = BIO_FLUSH;
1244 	beio->ds_trans_type = DEVSTAT_NO_DATA;
1245 	DPRINTF("SYNC\n");
1246 	be_lun->lun_flush(be_lun, beio);
1247 }
1248 
1249 static void
1250 ctl_be_block_cw_done_ws(struct ctl_be_block_io *beio)
1251 {
1252 	union ctl_io *io;
1253 
1254 	io = beio->io;
1255 	ctl_free_beio(beio);
1256 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1257 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1258 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1259 		ctl_config_write_done(io);
1260 		return;
1261 	}
1262 
1263 	ctl_be_block_config_write(io);
1264 }
1265 
1266 static void
1267 ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
1268 			    union ctl_io *io)
1269 {
1270 	struct ctl_be_block_softc *softc = be_lun->softc;
1271 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1272 	struct ctl_be_block_io *beio;
1273 	struct ctl_lba_len_flags *lbalen;
1274 	uint64_t len_left, lba;
1275 	uint32_t pb, pbo, adj;
1276 	int i, seglen;
1277 	uint8_t *buf, *end;
1278 
1279 	DPRINTF("entered\n");
1280 
1281 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1282 	lbalen = ARGS(beio->io);
1283 
1284 	if (lbalen->flags & ~(SWS_LBDATA | SWS_UNMAP | SWS_ANCHOR | SWS_NDOB) ||
1285 	    (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR) && be_lun->unmap == NULL)) {
1286 		ctl_free_beio(beio);
1287 		ctl_set_invalid_field(&io->scsiio,
1288 				      /*sks_valid*/ 1,
1289 				      /*command*/ 1,
1290 				      /*field*/ 1,
1291 				      /*bit_valid*/ 0,
1292 				      /*bit*/ 0);
1293 		ctl_config_write_done(io);
1294 		return;
1295 	}
1296 
1297 	if (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR)) {
1298 		beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1299 		beio->io_len = (uint64_t)lbalen->len * cbe_lun->blocksize;
1300 		beio->bio_cmd = BIO_DELETE;
1301 		beio->ds_trans_type = DEVSTAT_FREE;
1302 
1303 		be_lun->unmap(be_lun, beio);
1304 		return;
1305 	}
1306 
1307 	beio->bio_cmd = BIO_WRITE;
1308 	beio->ds_trans_type = DEVSTAT_WRITE;
1309 
1310 	DPRINTF("WRITE SAME at LBA %jx len %u\n",
1311 	       (uintmax_t)lbalen->lba, lbalen->len);
1312 
1313 	pb = cbe_lun->blocksize << be_lun->cbe_lun.pblockexp;
1314 	if (be_lun->cbe_lun.pblockoff > 0)
1315 		pbo = pb - cbe_lun->blocksize * be_lun->cbe_lun.pblockoff;
1316 	else
1317 		pbo = 0;
1318 	len_left = (uint64_t)lbalen->len * cbe_lun->blocksize;
1319 	for (i = 0, lba = 0; i < CTLBLK_MAX_SEGS && len_left > 0; i++) {
1320 
1321 		/*
1322 		 * Setup the S/G entry for this chunk.
1323 		 */
1324 		seglen = MIN(CTLBLK_MAX_SEG, len_left);
1325 		if (pb > cbe_lun->blocksize) {
1326 			adj = ((lbalen->lba + lba) * cbe_lun->blocksize +
1327 			    seglen - pbo) % pb;
1328 			if (seglen > adj)
1329 				seglen -= adj;
1330 			else
1331 				seglen -= seglen % cbe_lun->blocksize;
1332 		} else
1333 			seglen -= seglen % cbe_lun->blocksize;
1334 		beio->sg_segs[i].len = seglen;
1335 		beio->sg_segs[i].addr = uma_zalloc(softc->buf_zone, M_WAITOK);
1336 
1337 		DPRINTF("segment %d addr %p len %zd\n", i,
1338 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1339 
1340 		beio->num_segs++;
1341 		len_left -= seglen;
1342 
1343 		buf = beio->sg_segs[i].addr;
1344 		end = buf + seglen;
1345 		for (; buf < end; buf += cbe_lun->blocksize) {
1346 			if (lbalen->flags & SWS_NDOB) {
1347 				memset(buf, 0, cbe_lun->blocksize);
1348 			} else {
1349 				memcpy(buf, io->scsiio.kern_data_ptr,
1350 				    cbe_lun->blocksize);
1351 			}
1352 			if (lbalen->flags & SWS_LBDATA)
1353 				scsi_ulto4b(lbalen->lba + lba, buf);
1354 			lba++;
1355 		}
1356 	}
1357 
1358 	beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1359 	beio->io_len = lba * cbe_lun->blocksize;
1360 
1361 	/* We can not do all in one run. Correct and schedule rerun. */
1362 	if (len_left > 0) {
1363 		lbalen->lba += lba;
1364 		lbalen->len -= lba;
1365 		beio->beio_cont = ctl_be_block_cw_done_ws;
1366 	}
1367 
1368 	be_lun->dispatch(be_lun, beio);
1369 }
1370 
1371 static void
1372 ctl_be_block_cw_dispatch_unmap(struct ctl_be_block_lun *be_lun,
1373 			    union ctl_io *io)
1374 {
1375 	struct ctl_be_block_io *beio;
1376 	struct ctl_ptr_len_flags *ptrlen;
1377 
1378 	DPRINTF("entered\n");
1379 
1380 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1381 	ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1382 
1383 	if ((ptrlen->flags & ~SU_ANCHOR) != 0 || be_lun->unmap == NULL) {
1384 		ctl_free_beio(beio);
1385 		ctl_set_invalid_field(&io->scsiio,
1386 				      /*sks_valid*/ 0,
1387 				      /*command*/ 1,
1388 				      /*field*/ 0,
1389 				      /*bit_valid*/ 0,
1390 				      /*bit*/ 0);
1391 		ctl_config_write_done(io);
1392 		return;
1393 	}
1394 
1395 	beio->io_len = 0;
1396 	beio->io_offset = -1;
1397 	beio->bio_cmd = BIO_DELETE;
1398 	beio->ds_trans_type = DEVSTAT_FREE;
1399 	DPRINTF("UNMAP\n");
1400 	be_lun->unmap(be_lun, beio);
1401 }
1402 
1403 static void
1404 ctl_be_block_cr_done(struct ctl_be_block_io *beio)
1405 {
1406 	union ctl_io *io;
1407 
1408 	io = beio->io;
1409 	ctl_free_beio(beio);
1410 	ctl_config_read_done(io);
1411 }
1412 
1413 static void
1414 ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
1415 			 union ctl_io *io)
1416 {
1417 	struct ctl_be_block_io *beio;
1418 	struct ctl_be_block_softc *softc;
1419 
1420 	DPRINTF("entered\n");
1421 
1422 	softc = be_lun->softc;
1423 	beio = ctl_alloc_beio(softc);
1424 	beio->io = io;
1425 	beio->lun = be_lun;
1426 	beio->beio_cont = ctl_be_block_cr_done;
1427 	PRIV(io)->ptr = (void *)beio;
1428 
1429 	switch (io->scsiio.cdb[0]) {
1430 	case SERVICE_ACTION_IN:		/* GET LBA STATUS */
1431 		beio->bio_cmd = -1;
1432 		beio->ds_trans_type = DEVSTAT_NO_DATA;
1433 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1434 		beio->io_len = 0;
1435 		if (be_lun->get_lba_status)
1436 			be_lun->get_lba_status(be_lun, beio);
1437 		else
1438 			ctl_be_block_cr_done(beio);
1439 		break;
1440 	default:
1441 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1442 		break;
1443 	}
1444 }
1445 
1446 static void
1447 ctl_be_block_cw_done(struct ctl_be_block_io *beio)
1448 {
1449 	union ctl_io *io;
1450 
1451 	io = beio->io;
1452 	ctl_free_beio(beio);
1453 	ctl_config_write_done(io);
1454 }
1455 
1456 static void
1457 ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
1458 			 union ctl_io *io)
1459 {
1460 	struct ctl_be_block_io *beio;
1461 	struct ctl_be_block_softc *softc;
1462 
1463 	DPRINTF("entered\n");
1464 
1465 	softc = be_lun->softc;
1466 	beio = ctl_alloc_beio(softc);
1467 	beio->io = io;
1468 	beio->lun = be_lun;
1469 	beio->beio_cont = ctl_be_block_cw_done;
1470 	switch (io->scsiio.tag_type) {
1471 	case CTL_TAG_ORDERED:
1472 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1473 		break;
1474 	case CTL_TAG_HEAD_OF_QUEUE:
1475 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1476 		break;
1477 	case CTL_TAG_UNTAGGED:
1478 	case CTL_TAG_SIMPLE:
1479 	case CTL_TAG_ACA:
1480 	default:
1481 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1482 		break;
1483 	}
1484 	PRIV(io)->ptr = (void *)beio;
1485 
1486 	switch (io->scsiio.cdb[0]) {
1487 	case SYNCHRONIZE_CACHE:
1488 	case SYNCHRONIZE_CACHE_16:
1489 		ctl_be_block_cw_dispatch_sync(be_lun, io);
1490 		break;
1491 	case WRITE_SAME_10:
1492 	case WRITE_SAME_16:
1493 		ctl_be_block_cw_dispatch_ws(be_lun, io);
1494 		break;
1495 	case UNMAP:
1496 		ctl_be_block_cw_dispatch_unmap(be_lun, io);
1497 		break;
1498 	default:
1499 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1500 		break;
1501 	}
1502 }
1503 
1504 SDT_PROBE_DEFINE1(cbb, , read, start, "uint64_t");
1505 SDT_PROBE_DEFINE1(cbb, , write, start, "uint64_t");
1506 SDT_PROBE_DEFINE1(cbb, , read, alloc_done, "uint64_t");
1507 SDT_PROBE_DEFINE1(cbb, , write, alloc_done, "uint64_t");
1508 
1509 static void
1510 ctl_be_block_next(struct ctl_be_block_io *beio)
1511 {
1512 	struct ctl_be_block_lun *be_lun;
1513 	union ctl_io *io;
1514 
1515 	io = beio->io;
1516 	be_lun = beio->lun;
1517 	ctl_free_beio(beio);
1518 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1519 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1520 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1521 		ctl_data_submit_done(io);
1522 		return;
1523 	}
1524 
1525 	io->io_hdr.status &= ~CTL_STATUS_MASK;
1526 	io->io_hdr.status |= CTL_STATUS_NONE;
1527 
1528 	mtx_lock(&be_lun->queue_lock);
1529 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1530 	mtx_unlock(&be_lun->queue_lock);
1531 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1532 }
1533 
1534 static void
1535 ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
1536 			   union ctl_io *io)
1537 {
1538 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1539 	struct ctl_be_block_io *beio;
1540 	struct ctl_be_block_softc *softc;
1541 	struct ctl_lba_len_flags *lbalen;
1542 	struct ctl_ptr_len_flags *bptrlen;
1543 	uint64_t len_left, lbas;
1544 	int i;
1545 
1546 	softc = be_lun->softc;
1547 
1548 	DPRINTF("entered\n");
1549 
1550 	lbalen = ARGS(io);
1551 	if (lbalen->flags & CTL_LLF_WRITE) {
1552 		SDT_PROBE0(cbb, , write, start);
1553 	} else {
1554 		SDT_PROBE0(cbb, , read, start);
1555 	}
1556 
1557 	beio = ctl_alloc_beio(softc);
1558 	beio->io = io;
1559 	beio->lun = be_lun;
1560 	bptrlen = PRIV(io);
1561 	bptrlen->ptr = (void *)beio;
1562 
1563 	switch (io->scsiio.tag_type) {
1564 	case CTL_TAG_ORDERED:
1565 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1566 		break;
1567 	case CTL_TAG_HEAD_OF_QUEUE:
1568 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1569 		break;
1570 	case CTL_TAG_UNTAGGED:
1571 	case CTL_TAG_SIMPLE:
1572 	case CTL_TAG_ACA:
1573 	default:
1574 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1575 		break;
1576 	}
1577 
1578 	if (lbalen->flags & CTL_LLF_WRITE) {
1579 		beio->bio_cmd = BIO_WRITE;
1580 		beio->ds_trans_type = DEVSTAT_WRITE;
1581 	} else {
1582 		beio->bio_cmd = BIO_READ;
1583 		beio->ds_trans_type = DEVSTAT_READ;
1584 	}
1585 
1586 	DPRINTF("%s at LBA %jx len %u @%ju\n",
1587 	       (beio->bio_cmd == BIO_READ) ? "READ" : "WRITE",
1588 	       (uintmax_t)lbalen->lba, lbalen->len, bptrlen->len);
1589 	if (lbalen->flags & CTL_LLF_COMPARE) {
1590 		beio->two_sglists = 1;
1591 		lbas = CTLBLK_HALF_IO_SIZE;
1592 	} else {
1593 		lbas = CTLBLK_MAX_IO_SIZE;
1594 	}
1595 	lbas = MIN(lbalen->len - bptrlen->len, lbas / cbe_lun->blocksize);
1596 	beio->io_offset = (lbalen->lba + bptrlen->len) * cbe_lun->blocksize;
1597 	beio->io_len = lbas * cbe_lun->blocksize;
1598 	bptrlen->len += lbas;
1599 
1600 	for (i = 0, len_left = beio->io_len; len_left > 0; i++) {
1601 		KASSERT(i < CTLBLK_MAX_SEGS, ("Too many segs (%d >= %d)",
1602 		    i, CTLBLK_MAX_SEGS));
1603 
1604 		/*
1605 		 * Setup the S/G entry for this chunk.
1606 		 */
1607 		beio->sg_segs[i].len = min(CTLBLK_MAX_SEG, len_left);
1608 		beio->sg_segs[i].addr = uma_zalloc(softc->buf_zone, M_WAITOK);
1609 
1610 		DPRINTF("segment %d addr %p len %zd\n", i,
1611 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1612 
1613 		/* Set up second segment for compare operation. */
1614 		if (beio->two_sglists) {
1615 			beio->sg_segs[i + CTLBLK_HALF_SEGS].len =
1616 			    beio->sg_segs[i].len;
1617 			beio->sg_segs[i + CTLBLK_HALF_SEGS].addr =
1618 			    uma_zalloc(softc->buf_zone, M_WAITOK);
1619 		}
1620 
1621 		beio->num_segs++;
1622 		len_left -= beio->sg_segs[i].len;
1623 	}
1624 	if (bptrlen->len < lbalen->len)
1625 		beio->beio_cont = ctl_be_block_next;
1626 	io->scsiio.be_move_done = ctl_be_block_move_done;
1627 	/* For compare we have separate S/G lists for read and datamove. */
1628 	if (beio->two_sglists)
1629 		io->scsiio.kern_data_ptr = (uint8_t *)&beio->sg_segs[CTLBLK_HALF_SEGS];
1630 	else
1631 		io->scsiio.kern_data_ptr = (uint8_t *)beio->sg_segs;
1632 	io->scsiio.kern_data_len = beio->io_len;
1633 	io->scsiio.kern_sg_entries = beio->num_segs;
1634 	io->scsiio.kern_data_ref = ctl_refcnt_beio;
1635 	io->scsiio.kern_data_arg = beio;
1636 	io->io_hdr.flags |= CTL_FLAG_ALLOCATED;
1637 
1638 	/*
1639 	 * For the read case, we need to read the data into our buffers and
1640 	 * then we can send it back to the user.  For the write case, we
1641 	 * need to get the data from the user first.
1642 	 */
1643 	if (beio->bio_cmd == BIO_READ) {
1644 		SDT_PROBE0(cbb, , read, alloc_done);
1645 		be_lun->dispatch(be_lun, beio);
1646 	} else {
1647 		SDT_PROBE0(cbb, , write, alloc_done);
1648 #ifdef CTL_TIME_IO
1649 		getbinuptime(&io->io_hdr.dma_start_bt);
1650 #endif
1651 		ctl_datamove(io);
1652 	}
1653 }
1654 
1655 static void
1656 ctl_be_block_worker(void *context, int pending)
1657 {
1658 	struct ctl_be_block_lun *be_lun = (struct ctl_be_block_lun *)context;
1659 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1660 	union ctl_io *io;
1661 	struct ctl_be_block_io *beio;
1662 
1663 	DPRINTF("entered\n");
1664 	/*
1665 	 * Fetch and process I/Os from all queues.  If we detect LUN
1666 	 * CTL_LUN_FLAG_NO_MEDIA status here -- it is result of a race,
1667 	 * so make response maximally opaque to not confuse initiator.
1668 	 */
1669 	for (;;) {
1670 		mtx_lock(&be_lun->queue_lock);
1671 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->datamove_queue);
1672 		if (io != NULL) {
1673 			DPRINTF("datamove queue\n");
1674 			STAILQ_REMOVE(&be_lun->datamove_queue, &io->io_hdr,
1675 				      ctl_io_hdr, links);
1676 			mtx_unlock(&be_lun->queue_lock);
1677 			beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1678 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1679 				ctl_set_busy(&io->scsiio);
1680 				ctl_complete_beio(beio);
1681 				return;
1682 			}
1683 			be_lun->dispatch(be_lun, beio);
1684 			continue;
1685 		}
1686 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_write_queue);
1687 		if (io != NULL) {
1688 			DPRINTF("config write queue\n");
1689 			STAILQ_REMOVE(&be_lun->config_write_queue, &io->io_hdr,
1690 				      ctl_io_hdr, links);
1691 			mtx_unlock(&be_lun->queue_lock);
1692 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1693 				ctl_set_busy(&io->scsiio);
1694 				ctl_config_write_done(io);
1695 				return;
1696 			}
1697 			ctl_be_block_cw_dispatch(be_lun, io);
1698 			continue;
1699 		}
1700 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_read_queue);
1701 		if (io != NULL) {
1702 			DPRINTF("config read queue\n");
1703 			STAILQ_REMOVE(&be_lun->config_read_queue, &io->io_hdr,
1704 				      ctl_io_hdr, links);
1705 			mtx_unlock(&be_lun->queue_lock);
1706 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1707 				ctl_set_busy(&io->scsiio);
1708 				ctl_config_read_done(io);
1709 				return;
1710 			}
1711 			ctl_be_block_cr_dispatch(be_lun, io);
1712 			continue;
1713 		}
1714 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->input_queue);
1715 		if (io != NULL) {
1716 			DPRINTF("input queue\n");
1717 			STAILQ_REMOVE(&be_lun->input_queue, &io->io_hdr,
1718 				      ctl_io_hdr, links);
1719 			mtx_unlock(&be_lun->queue_lock);
1720 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1721 				ctl_set_busy(&io->scsiio);
1722 				ctl_data_submit_done(io);
1723 				return;
1724 			}
1725 			ctl_be_block_dispatch(be_lun, io);
1726 			continue;
1727 		}
1728 
1729 		/*
1730 		 * If we get here, there is no work left in the queues, so
1731 		 * just break out and let the task queue go to sleep.
1732 		 */
1733 		mtx_unlock(&be_lun->queue_lock);
1734 		break;
1735 	}
1736 }
1737 
1738 /*
1739  * Entry point from CTL to the backend for I/O.  We queue everything to a
1740  * work thread, so this just puts the I/O on a queue and wakes up the
1741  * thread.
1742  */
1743 static int
1744 ctl_be_block_submit(union ctl_io *io)
1745 {
1746 	struct ctl_be_block_lun *be_lun;
1747 
1748 	DPRINTF("entered\n");
1749 
1750 	be_lun = (struct ctl_be_block_lun *)CTL_BACKEND_LUN(io);
1751 
1752 	/*
1753 	 * Make sure we only get SCSI I/O.
1754 	 */
1755 	KASSERT(io->io_hdr.io_type == CTL_IO_SCSI, ("Non-SCSI I/O (type "
1756 		"%#x) encountered", io->io_hdr.io_type));
1757 
1758 	PRIV(io)->len = 0;
1759 
1760 	mtx_lock(&be_lun->queue_lock);
1761 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1762 	mtx_unlock(&be_lun->queue_lock);
1763 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1764 
1765 	return (CTL_RETVAL_COMPLETE);
1766 }
1767 
1768 static int
1769 ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
1770 			int flag, struct thread *td)
1771 {
1772 	struct ctl_be_block_softc *softc = &backend_block_softc;
1773 	int error;
1774 
1775 	error = 0;
1776 	switch (cmd) {
1777 	case CTL_LUN_REQ: {
1778 		struct ctl_lun_req *lun_req;
1779 
1780 		lun_req = (struct ctl_lun_req *)addr;
1781 
1782 		switch (lun_req->reqtype) {
1783 		case CTL_LUNREQ_CREATE:
1784 			error = ctl_be_block_create(softc, lun_req);
1785 			break;
1786 		case CTL_LUNREQ_RM:
1787 			error = ctl_be_block_rm(softc, lun_req);
1788 			break;
1789 		case CTL_LUNREQ_MODIFY:
1790 			error = ctl_be_block_modify(softc, lun_req);
1791 			break;
1792 		default:
1793 			lun_req->status = CTL_LUN_ERROR;
1794 			snprintf(lun_req->error_str, sizeof(lun_req->error_str),
1795 				 "invalid LUN request type %d",
1796 				 lun_req->reqtype);
1797 			break;
1798 		}
1799 		break;
1800 	}
1801 	default:
1802 		error = ENOTTY;
1803 		break;
1804 	}
1805 
1806 	return (error);
1807 }
1808 
1809 static int
1810 ctl_be_block_open_file(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1811 {
1812 	struct ctl_be_lun *cbe_lun;
1813 	struct ctl_be_block_filedata *file_data;
1814 	struct ctl_lun_create_params *params;
1815 	const char		     *value;
1816 	struct vattr		      vattr;
1817 	off_t			      ps, pss, po, pos, us, uss, uo, uos;
1818 	int			      error;
1819 
1820 	cbe_lun = &be_lun->cbe_lun;
1821 	file_data = &be_lun->backend.file;
1822 	params = &be_lun->params;
1823 
1824 	be_lun->dev_type = CTL_BE_BLOCK_FILE;
1825 	be_lun->dispatch = ctl_be_block_dispatch_file;
1826 	be_lun->lun_flush = ctl_be_block_flush_file;
1827 	be_lun->get_lba_status = ctl_be_block_gls_file;
1828 	be_lun->getattr = ctl_be_block_getattr_file;
1829 	be_lun->unmap = NULL;
1830 	cbe_lun->flags &= ~CTL_LUN_FLAG_UNMAP;
1831 
1832 	error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
1833 	if (error != 0) {
1834 		snprintf(req->error_str, sizeof(req->error_str),
1835 			 "error calling VOP_GETATTR() for file %s",
1836 			 be_lun->dev_path);
1837 		return (error);
1838 	}
1839 
1840 	file_data->cred = crhold(curthread->td_ucred);
1841 	if (params->lun_size_bytes != 0)
1842 		be_lun->size_bytes = params->lun_size_bytes;
1843 	else
1844 		be_lun->size_bytes = vattr.va_size;
1845 
1846 	/*
1847 	 * For files we can use any logical block size.  Prefer 512 bytes
1848 	 * for compatibility reasons.  If file's vattr.va_blocksize
1849 	 * (preferred I/O block size) is bigger and multiple to chosen
1850 	 * logical block size -- report it as physical block size.
1851 	 */
1852 	if (params->blocksize_bytes != 0)
1853 		cbe_lun->blocksize = params->blocksize_bytes;
1854 	else if (cbe_lun->lun_type == T_CDROM)
1855 		cbe_lun->blocksize = 2048;
1856 	else
1857 		cbe_lun->blocksize = 512;
1858 	be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
1859 	cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
1860 	    0 : (be_lun->size_blocks - 1);
1861 
1862 	us = ps = vattr.va_blocksize;
1863 	uo = po = 0;
1864 
1865 	value = dnvlist_get_string(cbe_lun->options, "pblocksize", NULL);
1866 	if (value != NULL)
1867 		ctl_expand_number(value, &ps);
1868 	value = dnvlist_get_string(cbe_lun->options, "pblockoffset", NULL);
1869 	if (value != NULL)
1870 		ctl_expand_number(value, &po);
1871 	pss = ps / cbe_lun->blocksize;
1872 	pos = po / cbe_lun->blocksize;
1873 	if ((pss > 0) && (pss * cbe_lun->blocksize == ps) && (pss >= pos) &&
1874 	    ((pss & (pss - 1)) == 0) && (pos * cbe_lun->blocksize == po)) {
1875 		cbe_lun->pblockexp = fls(pss) - 1;
1876 		cbe_lun->pblockoff = (pss - pos) % pss;
1877 	}
1878 
1879 	value = dnvlist_get_string(cbe_lun->options, "ublocksize", NULL);
1880 	if (value != NULL)
1881 		ctl_expand_number(value, &us);
1882 	value = dnvlist_get_string(cbe_lun->options, "ublockoffset", NULL);
1883 	if (value != NULL)
1884 		ctl_expand_number(value, &uo);
1885 	uss = us / cbe_lun->blocksize;
1886 	uos = uo / cbe_lun->blocksize;
1887 	if ((uss > 0) && (uss * cbe_lun->blocksize == us) && (uss >= uos) &&
1888 	    ((uss & (uss - 1)) == 0) && (uos * cbe_lun->blocksize == uo)) {
1889 		cbe_lun->ublockexp = fls(uss) - 1;
1890 		cbe_lun->ublockoff = (uss - uos) % uss;
1891 	}
1892 
1893 	/*
1894 	 * Sanity check.  The media size has to be at least one
1895 	 * sector long.
1896 	 */
1897 	if (be_lun->size_bytes < cbe_lun->blocksize) {
1898 		error = EINVAL;
1899 		snprintf(req->error_str, sizeof(req->error_str),
1900 			 "file %s size %ju < block size %u", be_lun->dev_path,
1901 			 (uintmax_t)be_lun->size_bytes, cbe_lun->blocksize);
1902 	}
1903 
1904 	cbe_lun->opttxferlen = CTLBLK_MAX_IO_SIZE / cbe_lun->blocksize;
1905 	return (error);
1906 }
1907 
1908 static int
1909 ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1910 {
1911 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1912 	struct ctl_lun_create_params *params;
1913 	struct cdevsw		     *csw;
1914 	struct cdev		     *dev;
1915 	const char		     *value;
1916 	int			      error, atomic, maxio, ref, unmap, tmp;
1917 	off_t			      ps, pss, po, pos, us, uss, uo, uos, otmp;
1918 
1919 	params = &be_lun->params;
1920 
1921 	be_lun->dev_type = CTL_BE_BLOCK_DEV;
1922 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1923 	if (csw == NULL)
1924 		return (ENXIO);
1925 	if (strcmp(csw->d_name, "zvol") == 0) {
1926 		be_lun->dispatch = ctl_be_block_dispatch_zvol;
1927 		be_lun->get_lba_status = ctl_be_block_gls_zvol;
1928 		atomic = maxio = CTLBLK_MAX_IO_SIZE;
1929 	} else {
1930 		be_lun->dispatch = ctl_be_block_dispatch_dev;
1931 		be_lun->get_lba_status = NULL;
1932 		atomic = 0;
1933 		maxio = dev->si_iosize_max;
1934 		if (maxio <= 0)
1935 			maxio = DFLTPHYS;
1936 		if (maxio > CTLBLK_MAX_IO_SIZE)
1937 			maxio = CTLBLK_MAX_IO_SIZE;
1938 	}
1939 	be_lun->lun_flush = ctl_be_block_flush_dev;
1940 	be_lun->getattr = ctl_be_block_getattr_dev;
1941 	be_lun->unmap = ctl_be_block_unmap_dev;
1942 
1943 	if (!csw->d_ioctl) {
1944 		dev_relthread(dev, ref);
1945 		snprintf(req->error_str, sizeof(req->error_str),
1946 			 "no d_ioctl for device %s!", be_lun->dev_path);
1947 		return (ENODEV);
1948 	}
1949 
1950 	error = csw->d_ioctl(dev, DIOCGSECTORSIZE, (caddr_t)&tmp, FREAD,
1951 			       curthread);
1952 	if (error) {
1953 		dev_relthread(dev, ref);
1954 		snprintf(req->error_str, sizeof(req->error_str),
1955 			 "error %d returned for DIOCGSECTORSIZE ioctl "
1956 			 "on %s!", error, be_lun->dev_path);
1957 		return (error);
1958 	}
1959 
1960 	/*
1961 	 * If the user has asked for a blocksize that is greater than the
1962 	 * backing device's blocksize, we can do it only if the blocksize
1963 	 * the user is asking for is an even multiple of the underlying
1964 	 * device's blocksize.
1965 	 */
1966 	if ((params->blocksize_bytes != 0) &&
1967 	    (params->blocksize_bytes >= tmp)) {
1968 		if (params->blocksize_bytes % tmp == 0) {
1969 			cbe_lun->blocksize = params->blocksize_bytes;
1970 		} else {
1971 			dev_relthread(dev, ref);
1972 			snprintf(req->error_str, sizeof(req->error_str),
1973 				 "requested blocksize %u is not an even "
1974 				 "multiple of backing device blocksize %u",
1975 				 params->blocksize_bytes, tmp);
1976 			return (EINVAL);
1977 		}
1978 	} else if (params->blocksize_bytes != 0) {
1979 		dev_relthread(dev, ref);
1980 		snprintf(req->error_str, sizeof(req->error_str),
1981 			 "requested blocksize %u < backing device "
1982 			 "blocksize %u", params->blocksize_bytes, tmp);
1983 		return (EINVAL);
1984 	} else if (cbe_lun->lun_type == T_CDROM)
1985 		cbe_lun->blocksize = MAX(tmp, 2048);
1986 	else
1987 		cbe_lun->blocksize = tmp;
1988 
1989 	error = csw->d_ioctl(dev, DIOCGMEDIASIZE, (caddr_t)&otmp, FREAD,
1990 			     curthread);
1991 	if (error) {
1992 		dev_relthread(dev, ref);
1993 		snprintf(req->error_str, sizeof(req->error_str),
1994 			 "error %d returned for DIOCGMEDIASIZE "
1995 			 " ioctl on %s!", error,
1996 			 be_lun->dev_path);
1997 		return (error);
1998 	}
1999 
2000 	if (params->lun_size_bytes != 0) {
2001 		if (params->lun_size_bytes > otmp) {
2002 			dev_relthread(dev, ref);
2003 			snprintf(req->error_str, sizeof(req->error_str),
2004 				 "requested LUN size %ju > backing device "
2005 				 "size %ju",
2006 				 (uintmax_t)params->lun_size_bytes,
2007 				 (uintmax_t)otmp);
2008 			return (EINVAL);
2009 		}
2010 
2011 		be_lun->size_bytes = params->lun_size_bytes;
2012 	} else
2013 		be_lun->size_bytes = otmp;
2014 	be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
2015 	cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
2016 	    0 : (be_lun->size_blocks - 1);
2017 
2018 	error = csw->d_ioctl(dev, DIOCGSTRIPESIZE, (caddr_t)&ps, FREAD,
2019 	    curthread);
2020 	if (error)
2021 		ps = po = 0;
2022 	else {
2023 		error = csw->d_ioctl(dev, DIOCGSTRIPEOFFSET, (caddr_t)&po,
2024 		    FREAD, curthread);
2025 		if (error)
2026 			po = 0;
2027 	}
2028 	us = ps;
2029 	uo = po;
2030 
2031 	value = dnvlist_get_string(cbe_lun->options, "pblocksize", NULL);
2032 	if (value != NULL)
2033 		ctl_expand_number(value, &ps);
2034 	value = dnvlist_get_string(cbe_lun->options, "pblockoffset", NULL);
2035 	if (value != NULL)
2036 		ctl_expand_number(value, &po);
2037 	pss = ps / cbe_lun->blocksize;
2038 	pos = po / cbe_lun->blocksize;
2039 	if ((pss > 0) && (pss * cbe_lun->blocksize == ps) && (pss >= pos) &&
2040 	    ((pss & (pss - 1)) == 0) && (pos * cbe_lun->blocksize == po)) {
2041 		cbe_lun->pblockexp = fls(pss) - 1;
2042 		cbe_lun->pblockoff = (pss - pos) % pss;
2043 	}
2044 
2045 	value = dnvlist_get_string(cbe_lun->options, "ublocksize", NULL);
2046 	if (value != NULL)
2047 		ctl_expand_number(value, &us);
2048 	value = dnvlist_get_string(cbe_lun->options, "ublockoffset", NULL);
2049 	if (value != NULL)
2050 		ctl_expand_number(value, &uo);
2051 	uss = us / cbe_lun->blocksize;
2052 	uos = uo / cbe_lun->blocksize;
2053 	if ((uss > 0) && (uss * cbe_lun->blocksize == us) && (uss >= uos) &&
2054 	    ((uss & (uss - 1)) == 0) && (uos * cbe_lun->blocksize == uo)) {
2055 		cbe_lun->ublockexp = fls(uss) - 1;
2056 		cbe_lun->ublockoff = (uss - uos) % uss;
2057 	}
2058 
2059 	cbe_lun->atomicblock = atomic / cbe_lun->blocksize;
2060 	cbe_lun->opttxferlen = maxio / cbe_lun->blocksize;
2061 
2062 	if (be_lun->dispatch == ctl_be_block_dispatch_zvol) {
2063 		unmap = 1;
2064 	} else {
2065 		struct diocgattr_arg	arg;
2066 
2067 		strlcpy(arg.name, "GEOM::candelete", sizeof(arg.name));
2068 		arg.len = sizeof(arg.value.i);
2069 		error = csw->d_ioctl(dev, DIOCGATTR, (caddr_t)&arg, FREAD,
2070 		    curthread);
2071 		unmap = (error == 0) ? arg.value.i : 0;
2072 	}
2073 	value = dnvlist_get_string(cbe_lun->options, "unmap", NULL);
2074 	if (value != NULL)
2075 		unmap = (strcmp(value, "on") == 0);
2076 	if (unmap)
2077 		cbe_lun->flags |= CTL_LUN_FLAG_UNMAP;
2078 	else
2079 		cbe_lun->flags &= ~CTL_LUN_FLAG_UNMAP;
2080 
2081 	dev_relthread(dev, ref);
2082 	return (0);
2083 }
2084 
2085 static int
2086 ctl_be_block_close(struct ctl_be_block_lun *be_lun)
2087 {
2088 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
2089 	int flags;
2090 
2091 	if (be_lun->vn) {
2092 		flags = FREAD;
2093 		if ((cbe_lun->flags & CTL_LUN_FLAG_READONLY) == 0)
2094 			flags |= FWRITE;
2095 		(void)vn_close(be_lun->vn, flags, NOCRED, curthread);
2096 		be_lun->vn = NULL;
2097 
2098 		switch (be_lun->dev_type) {
2099 		case CTL_BE_BLOCK_DEV:
2100 			break;
2101 		case CTL_BE_BLOCK_FILE:
2102 			if (be_lun->backend.file.cred != NULL) {
2103 				crfree(be_lun->backend.file.cred);
2104 				be_lun->backend.file.cred = NULL;
2105 			}
2106 			break;
2107 		case CTL_BE_BLOCK_NONE:
2108 			break;
2109 		default:
2110 			panic("Unexpected backend type %d", be_lun->dev_type);
2111 			break;
2112 		}
2113 		be_lun->dev_type = CTL_BE_BLOCK_NONE;
2114 	}
2115 	return (0);
2116 }
2117 
2118 static int
2119 ctl_be_block_open(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
2120 {
2121 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
2122 	struct nameidata nd;
2123 	const char	*value;
2124 	int		 error, flags;
2125 
2126 	error = 0;
2127 	if (rootvnode == NULL) {
2128 		snprintf(req->error_str, sizeof(req->error_str),
2129 			 "Root filesystem is not mounted");
2130 		return (1);
2131 	}
2132 	pwd_ensure_dirs();
2133 
2134 	value = dnvlist_get_string(cbe_lun->options, "file", NULL);
2135 	if (value == NULL) {
2136 		snprintf(req->error_str, sizeof(req->error_str),
2137 			 "no file argument specified");
2138 		return (1);
2139 	}
2140 	free(be_lun->dev_path, M_CTLBLK);
2141 	be_lun->dev_path = strdup(value, M_CTLBLK);
2142 
2143 	flags = FREAD;
2144 	value = dnvlist_get_string(cbe_lun->options, "readonly", NULL);
2145 	if (value != NULL) {
2146 		if (strcmp(value, "on") != 0)
2147 			flags |= FWRITE;
2148 	} else if (cbe_lun->lun_type == T_DIRECT)
2149 		flags |= FWRITE;
2150 
2151 again:
2152 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, be_lun->dev_path, curthread);
2153 	error = vn_open(&nd, &flags, 0, NULL);
2154 	if ((error == EROFS || error == EACCES) && (flags & FWRITE)) {
2155 		flags &= ~FWRITE;
2156 		goto again;
2157 	}
2158 	if (error) {
2159 		/*
2160 		 * This is the only reasonable guess we can make as far as
2161 		 * path if the user doesn't give us a fully qualified path.
2162 		 * If they want to specify a file, they need to specify the
2163 		 * full path.
2164 		 */
2165 		if (be_lun->dev_path[0] != '/') {
2166 			char *dev_name;
2167 
2168 			asprintf(&dev_name, M_CTLBLK, "/dev/%s",
2169 				be_lun->dev_path);
2170 			free(be_lun->dev_path, M_CTLBLK);
2171 			be_lun->dev_path = dev_name;
2172 			goto again;
2173 		}
2174 		snprintf(req->error_str, sizeof(req->error_str),
2175 		    "error opening %s: %d", be_lun->dev_path, error);
2176 		return (error);
2177 	}
2178 	if (flags & FWRITE)
2179 		cbe_lun->flags &= ~CTL_LUN_FLAG_READONLY;
2180 	else
2181 		cbe_lun->flags |= CTL_LUN_FLAG_READONLY;
2182 
2183 	NDFREE(&nd, NDF_ONLY_PNBUF);
2184 	be_lun->vn = nd.ni_vp;
2185 
2186 	/* We only support disks and files. */
2187 	if (vn_isdisk(be_lun->vn, &error)) {
2188 		error = ctl_be_block_open_dev(be_lun, req);
2189 	} else if (be_lun->vn->v_type == VREG) {
2190 		error = ctl_be_block_open_file(be_lun, req);
2191 	} else {
2192 		error = EINVAL;
2193 		snprintf(req->error_str, sizeof(req->error_str),
2194 			 "%s is not a disk or plain file", be_lun->dev_path);
2195 	}
2196 	VOP_UNLOCK(be_lun->vn);
2197 
2198 	if (error != 0)
2199 		ctl_be_block_close(be_lun);
2200 	cbe_lun->serseq = CTL_LUN_SERSEQ_OFF;
2201 	if (be_lun->dispatch != ctl_be_block_dispatch_dev)
2202 		cbe_lun->serseq = CTL_LUN_SERSEQ_READ;
2203 	value = dnvlist_get_string(cbe_lun->options, "serseq", NULL);
2204 	if (value != NULL && strcmp(value, "on") == 0)
2205 		cbe_lun->serseq = CTL_LUN_SERSEQ_ON;
2206 	else if (value != NULL && strcmp(value, "read") == 0)
2207 		cbe_lun->serseq = CTL_LUN_SERSEQ_READ;
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(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->buf_zone = uma_zcreate("ctlblock", CTLBLK_MAX_SEG,
2781 	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
2782 	SLIST_INIT(&softc->lun_list);
2783 	return (0);
2784 }
2785 
2786 
2787 static int
2788 ctl_be_block_shutdown(void)
2789 {
2790 	struct ctl_be_block_softc *softc = &backend_block_softc;
2791 	struct ctl_be_block_lun *lun;
2792 
2793 	mtx_lock(&softc->lock);
2794 	while ((lun = SLIST_FIRST(&softc->lun_list)) != NULL) {
2795 		SLIST_REMOVE_HEAD(&softc->lun_list, links);
2796 		softc->num_luns--;
2797 		/*
2798 		 * Drop our lock here.  Since ctl_remove_lun() can call
2799 		 * back into us, this could potentially lead to a recursive
2800 		 * lock of the same mutex, which would cause a hang.
2801 		 */
2802 		mtx_unlock(&softc->lock);
2803 		ctl_remove_lun(&lun->cbe_lun);
2804 		mtx_lock(&softc->lock);
2805 	}
2806 	mtx_unlock(&softc->lock);
2807 	uma_zdestroy(softc->buf_zone);
2808 	uma_zdestroy(softc->beio_zone);
2809 	mtx_destroy(&softc->lock);
2810 	sx_destroy(&softc->modify_lock);
2811 	return (0);
2812 }
2813