xref: /freebsd/sys/cam/ctl/ctl_backend_block.c (revision 5596f836e7e04a272113e57b3a80f1f67c0fec7f)
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		MIN(CTLBLK_HALF_IO_SIZE, 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 #if (CTLBLK_MAX_SEG > 131072)
194 	uma_zone_t			 buf128_zone;
195 #endif
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 = 14;
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);
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 	.data_move_done = ctl_be_block_move_done,
295 	.config_read = ctl_be_block_config_read,
296 	.config_write = ctl_be_block_config_write,
297 	.ioctl = ctl_be_block_ioctl,
298 	.lun_info = ctl_be_block_lun_info,
299 	.lun_attr = ctl_be_block_lun_attr
300 };
301 
302 MALLOC_DEFINE(M_CTLBLK, "ctlblock", "Memory used for CTL block backend");
303 CTL_BACKEND_DECLARE(cbb, ctl_be_block_driver);
304 
305 static void
306 ctl_alloc_seg(struct ctl_be_block_softc *softc, struct ctl_sg_entry *sg,
307     size_t len)
308 {
309 
310 #if (CTLBLK_MAX_SEG > 131072)
311 	if (len <= 131072)
312 		sg->addr = uma_zalloc(softc->buf128_zone, M_WAITOK);
313 	else
314 #endif
315 		sg->addr = uma_zalloc(softc->buf_zone, M_WAITOK);
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 (CTLBLK_MAX_SEG > 131072)
324 	if (sg->len <= 131072)
325 		uma_zfree(softc->buf128_zone, sg->addr);
326 	else
327 #endif
328 		uma_zfree(softc->buf_zone, sg->addr);
329 }
330 
331 static struct ctl_be_block_io *
332 ctl_alloc_beio(struct ctl_be_block_softc *softc)
333 {
334 	struct ctl_be_block_io *beio;
335 
336 	beio = uma_zalloc(softc->beio_zone, M_WAITOK | M_ZERO);
337 	beio->softc = softc;
338 	beio->refcnt = 1;
339 	return (beio);
340 }
341 
342 static void
343 ctl_real_free_beio(struct ctl_be_block_io *beio)
344 {
345 	struct ctl_be_block_softc *softc = beio->softc;
346 	int i;
347 
348 	for (i = 0; i < beio->num_segs; i++) {
349 		ctl_free_seg(softc, &beio->sg_segs[i]);
350 
351 		/* For compare we had two equal S/G lists. */
352 		if (beio->two_sglists) {
353 			ctl_free_seg(softc,
354 			    &beio->sg_segs[i + CTLBLK_HALF_SEGS]);
355 		}
356 	}
357 
358 	uma_zfree(softc->beio_zone, beio);
359 }
360 
361 static void
362 ctl_refcnt_beio(void *arg, int diff)
363 {
364 	struct ctl_be_block_io *beio = arg;
365 
366 	if (atomic_fetchadd_int(&beio->refcnt, diff) + diff == 0)
367 		ctl_real_free_beio(beio);
368 }
369 
370 static void
371 ctl_free_beio(struct ctl_be_block_io *beio)
372 {
373 
374 	ctl_refcnt_beio(beio, -1);
375 }
376 
377 static void
378 ctl_complete_beio(struct ctl_be_block_io *beio)
379 {
380 	union ctl_io *io = beio->io;
381 
382 	if (beio->beio_cont != NULL) {
383 		beio->beio_cont(beio);
384 	} else {
385 		ctl_free_beio(beio);
386 		ctl_data_submit_done(io);
387 	}
388 }
389 
390 static size_t
391 cmp(uint8_t *a, uint8_t *b, size_t size)
392 {
393 	size_t i;
394 
395 	for (i = 0; i < size; i++) {
396 		if (a[i] != b[i])
397 			break;
398 	}
399 	return (i);
400 }
401 
402 static void
403 ctl_be_block_compare(union ctl_io *io)
404 {
405 	struct ctl_be_block_io *beio;
406 	uint64_t off, res;
407 	int i;
408 	uint8_t info[8];
409 
410 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
411 	off = 0;
412 	for (i = 0; i < beio->num_segs; i++) {
413 		res = cmp(beio->sg_segs[i].addr,
414 		    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr,
415 		    beio->sg_segs[i].len);
416 		off += res;
417 		if (res < beio->sg_segs[i].len)
418 			break;
419 	}
420 	if (i < beio->num_segs) {
421 		scsi_u64to8b(off, info);
422 		ctl_set_sense(&io->scsiio, /*current_error*/ 1,
423 		    /*sense_key*/ SSD_KEY_MISCOMPARE,
424 		    /*asc*/ 0x1D, /*ascq*/ 0x00,
425 		    /*type*/ SSD_ELEM_INFO,
426 		    /*size*/ sizeof(info), /*data*/ &info,
427 		    /*type*/ SSD_ELEM_NONE);
428 	} else
429 		ctl_set_success(&io->scsiio);
430 }
431 
432 static int
433 ctl_be_block_move_done(union ctl_io *io)
434 {
435 	struct ctl_be_block_io *beio;
436 	struct ctl_be_block_lun *be_lun;
437 	struct ctl_lba_len_flags *lbalen;
438 #ifdef CTL_TIME_IO
439 	struct bintime cur_bt;
440 #endif
441 
442 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
443 	be_lun = beio->lun;
444 
445 	DPRINTF("entered\n");
446 
447 #ifdef CTL_TIME_IO
448 	getbinuptime(&cur_bt);
449 	bintime_sub(&cur_bt, &io->io_hdr.dma_start_bt);
450 	bintime_add(&io->io_hdr.dma_bt, &cur_bt);
451 #endif
452 	io->io_hdr.num_dmas++;
453 	io->scsiio.kern_rel_offset += io->scsiio.kern_data_len;
454 
455 	/*
456 	 * We set status at this point for read commands, and write
457 	 * commands with errors.
458 	 */
459 	if (io->io_hdr.flags & CTL_FLAG_ABORT) {
460 		;
461 	} else if ((io->io_hdr.port_status != 0) &&
462 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE ||
463 	     (io->io_hdr.status & CTL_STATUS_MASK) == CTL_SUCCESS)) {
464 		ctl_set_internal_failure(&io->scsiio, /*sks_valid*/ 1,
465 		    /*retry_count*/ io->io_hdr.port_status);
466 	} else if (io->scsiio.kern_data_resid != 0 &&
467 	    (io->io_hdr.flags & CTL_FLAG_DATA_MASK) == CTL_FLAG_DATA_OUT &&
468 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE ||
469 	     (io->io_hdr.status & CTL_STATUS_MASK) == CTL_SUCCESS)) {
470 		ctl_set_invalid_field_ciu(&io->scsiio);
471 	} else if ((io->io_hdr.port_status == 0) &&
472 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE)) {
473 		lbalen = ARGS(beio->io);
474 		if (lbalen->flags & CTL_LLF_READ) {
475 			ctl_set_success(&io->scsiio);
476 		} else if (lbalen->flags & CTL_LLF_COMPARE) {
477 			/* We have two data blocks ready for comparison. */
478 			ctl_be_block_compare(io);
479 		}
480 	}
481 
482 	/*
483 	 * If this is a read, or a write with errors, it is done.
484 	 */
485 	if ((beio->bio_cmd == BIO_READ)
486 	 || ((io->io_hdr.flags & CTL_FLAG_ABORT) != 0)
487 	 || ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE)) {
488 		ctl_complete_beio(beio);
489 		return (0);
490 	}
491 
492 	/*
493 	 * At this point, we have a write and the DMA completed
494 	 * successfully.  We now have to queue it to the task queue to
495 	 * execute the backend I/O.  That is because we do blocking
496 	 * memory allocations, and in the file backing case, blocking I/O.
497 	 * This move done routine is generally called in the SIM's
498 	 * interrupt context, and therefore we cannot block.
499 	 */
500 	mtx_lock(&be_lun->queue_lock);
501 	STAILQ_INSERT_TAIL(&be_lun->datamove_queue, &io->io_hdr, links);
502 	mtx_unlock(&be_lun->queue_lock);
503 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
504 
505 	return (0);
506 }
507 
508 static void
509 ctl_be_block_biodone(struct bio *bio)
510 {
511 	struct ctl_be_block_io *beio;
512 	struct ctl_be_block_lun *be_lun;
513 	union ctl_io *io;
514 	int error;
515 
516 	beio = bio->bio_caller1;
517 	be_lun = beio->lun;
518 	io = beio->io;
519 
520 	DPRINTF("entered\n");
521 
522 	error = bio->bio_error;
523 	mtx_lock(&be_lun->io_lock);
524 	if (error != 0 &&
525 	    (beio->first_error == 0 ||
526 	     bio->bio_offset < beio->first_error_offset)) {
527 		beio->first_error = error;
528 		beio->first_error_offset = bio->bio_offset;
529 	}
530 
531 	beio->num_bios_done++;
532 
533 	/*
534 	 * XXX KDM will this cause WITNESS to complain?  Holding a lock
535 	 * during the free might cause it to complain.
536 	 */
537 	g_destroy_bio(bio);
538 
539 	/*
540 	 * If the send complete bit isn't set, or we aren't the last I/O to
541 	 * complete, then we're done.
542 	 */
543 	if ((beio->send_complete == 0)
544 	 || (beio->num_bios_done < beio->num_bios_sent)) {
545 		mtx_unlock(&be_lun->io_lock);
546 		return;
547 	}
548 
549 	/*
550 	 * At this point, we've verified that we are the last I/O to
551 	 * complete, so it's safe to drop the lock.
552 	 */
553 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
554 	    beio->ds_tag_type, beio->ds_trans_type,
555 	    /*now*/ NULL, /*then*/&beio->ds_t0);
556 	mtx_unlock(&be_lun->io_lock);
557 
558 	/*
559 	 * If there are any errors from the backing device, we fail the
560 	 * entire I/O with a medium error.
561 	 */
562 	error = beio->first_error;
563 	if (error != 0) {
564 		if (error == EOPNOTSUPP) {
565 			ctl_set_invalid_opcode(&io->scsiio);
566 		} else if (error == ENOSPC || error == EDQUOT) {
567 			ctl_set_space_alloc_fail(&io->scsiio);
568 		} else if (error == EROFS || error == EACCES) {
569 			ctl_set_hw_write_protected(&io->scsiio);
570 		} else if (beio->bio_cmd == BIO_FLUSH) {
571 			/* XXX KDM is there is a better error here? */
572 			ctl_set_internal_failure(&io->scsiio,
573 						 /*sks_valid*/ 1,
574 						 /*retry_count*/ 0xbad2);
575 		} else {
576 			ctl_set_medium_error(&io->scsiio,
577 			    beio->bio_cmd == BIO_READ);
578 		}
579 		ctl_complete_beio(beio);
580 		return;
581 	}
582 
583 	/*
584 	 * If this is a write, a flush, a delete or verify, we're all done.
585 	 * If this is a read, we can now send the data to the user.
586 	 */
587 	if ((beio->bio_cmd == BIO_WRITE)
588 	 || (beio->bio_cmd == BIO_FLUSH)
589 	 || (beio->bio_cmd == BIO_DELETE)
590 	 || (ARGS(io)->flags & CTL_LLF_VERIFY)) {
591 		ctl_set_success(&io->scsiio);
592 		ctl_complete_beio(beio);
593 	} else {
594 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
595 		    beio->beio_cont == NULL) {
596 			ctl_set_success(&io->scsiio);
597 			ctl_serseq_done(io);
598 		}
599 #ifdef CTL_TIME_IO
600 		getbinuptime(&io->io_hdr.dma_start_bt);
601 #endif
602 		ctl_datamove(io);
603 	}
604 }
605 
606 static void
607 ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
608 			struct ctl_be_block_io *beio)
609 {
610 	union ctl_io *io = beio->io;
611 	struct mount *mountpoint;
612 	int error, lock_flags;
613 
614 	DPRINTF("entered\n");
615 
616 	binuptime(&beio->ds_t0);
617 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
618 
619 	(void) vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
620 
621 	if (MNT_SHARED_WRITES(mountpoint) ||
622 	    ((mountpoint == NULL) && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
623 		lock_flags = LK_SHARED;
624 	else
625 		lock_flags = LK_EXCLUSIVE;
626 	vn_lock(be_lun->vn, lock_flags | LK_RETRY);
627 	error = VOP_FSYNC(be_lun->vn, beio->io_arg ? MNT_NOWAIT : MNT_WAIT,
628 	    curthread);
629 	VOP_UNLOCK(be_lun->vn);
630 
631 	vn_finished_write(mountpoint);
632 
633 	mtx_lock(&be_lun->io_lock);
634 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
635 	    beio->ds_tag_type, beio->ds_trans_type,
636 	    /*now*/ NULL, /*then*/&beio->ds_t0);
637 	mtx_unlock(&be_lun->io_lock);
638 
639 	if (error == 0)
640 		ctl_set_success(&io->scsiio);
641 	else {
642 		/* XXX KDM is there is a better error here? */
643 		ctl_set_internal_failure(&io->scsiio,
644 					 /*sks_valid*/ 1,
645 					 /*retry_count*/ 0xbad1);
646 	}
647 
648 	ctl_complete_beio(beio);
649 }
650 
651 SDT_PROBE_DEFINE1(cbb, , read, file_start, "uint64_t");
652 SDT_PROBE_DEFINE1(cbb, , write, file_start, "uint64_t");
653 SDT_PROBE_DEFINE1(cbb, , read, file_done,"uint64_t");
654 SDT_PROBE_DEFINE1(cbb, , write, file_done, "uint64_t");
655 
656 static void
657 ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
658 			   struct ctl_be_block_io *beio)
659 {
660 	struct ctl_be_block_filedata *file_data;
661 	union ctl_io *io;
662 	struct uio xuio;
663 	struct iovec *xiovec;
664 	size_t s;
665 	int error, flags, i;
666 
667 	DPRINTF("entered\n");
668 
669 	file_data = &be_lun->backend.file;
670 	io = beio->io;
671 	flags = 0;
672 	if (ARGS(io)->flags & CTL_LLF_DPO)
673 		flags |= IO_DIRECT;
674 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
675 		flags |= IO_SYNC;
676 
677 	bzero(&xuio, sizeof(xuio));
678 	if (beio->bio_cmd == BIO_READ) {
679 		SDT_PROBE0(cbb, , read, file_start);
680 		xuio.uio_rw = UIO_READ;
681 	} else {
682 		SDT_PROBE0(cbb, , write, file_start);
683 		xuio.uio_rw = UIO_WRITE;
684 	}
685 	xuio.uio_offset = beio->io_offset;
686 	xuio.uio_resid = beio->io_len;
687 	xuio.uio_segflg = UIO_SYSSPACE;
688 	xuio.uio_iov = beio->xiovecs;
689 	xuio.uio_iovcnt = beio->num_segs;
690 	xuio.uio_td = curthread;
691 
692 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
693 		xiovec->iov_base = beio->sg_segs[i].addr;
694 		xiovec->iov_len = beio->sg_segs[i].len;
695 	}
696 
697 	binuptime(&beio->ds_t0);
698 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
699 
700 	if (beio->bio_cmd == BIO_READ) {
701 		vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
702 
703 		/*
704 		 * UFS pays attention to IO_DIRECT for reads.  If the
705 		 * DIRECTIO option is configured into the kernel, it calls
706 		 * ffs_rawread().  But that only works for single-segment
707 		 * uios with user space addresses.  In our case, with a
708 		 * kernel uio, it still reads into the buffer cache, but it
709 		 * will just try to release the buffer from the cache later
710 		 * on in ffs_read().
711 		 *
712 		 * ZFS does not pay attention to IO_DIRECT for reads.
713 		 *
714 		 * UFS does not pay attention to IO_SYNC for reads.
715 		 *
716 		 * ZFS pays attention to IO_SYNC (which translates into the
717 		 * Solaris define FRSYNC for zfs_read()) for reads.  It
718 		 * attempts to sync the file before reading.
719 		 */
720 		error = VOP_READ(be_lun->vn, &xuio, flags, file_data->cred);
721 
722 		VOP_UNLOCK(be_lun->vn);
723 		SDT_PROBE0(cbb, , read, file_done);
724 		if (error == 0 && xuio.uio_resid > 0) {
725 			/*
726 			 * If we red less then requested (EOF), then
727 			 * we should clean the rest of the buffer.
728 			 */
729 			s = beio->io_len - xuio.uio_resid;
730 			for (i = 0; i < beio->num_segs; i++) {
731 				if (s >= beio->sg_segs[i].len) {
732 					s -= beio->sg_segs[i].len;
733 					continue;
734 				}
735 				bzero((uint8_t *)beio->sg_segs[i].addr + s,
736 				    beio->sg_segs[i].len - s);
737 				s = 0;
738 			}
739 		}
740 	} else {
741 		struct mount *mountpoint;
742 		int lock_flags;
743 
744 		(void)vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
745 
746 		if (MNT_SHARED_WRITES(mountpoint) || ((mountpoint == NULL)
747 		  && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
748 			lock_flags = LK_SHARED;
749 		else
750 			lock_flags = LK_EXCLUSIVE;
751 		vn_lock(be_lun->vn, lock_flags | LK_RETRY);
752 
753 		/*
754 		 * UFS pays attention to IO_DIRECT for writes.  The write
755 		 * is done asynchronously.  (Normally the write would just
756 		 * get put into cache.
757 		 *
758 		 * UFS pays attention to IO_SYNC for writes.  It will
759 		 * attempt to write the buffer out synchronously if that
760 		 * flag is set.
761 		 *
762 		 * ZFS does not pay attention to IO_DIRECT for writes.
763 		 *
764 		 * ZFS pays attention to IO_SYNC (a.k.a. FSYNC or FRSYNC)
765 		 * for writes.  It will flush the transaction from the
766 		 * cache before returning.
767 		 */
768 		error = VOP_WRITE(be_lun->vn, &xuio, flags, file_data->cred);
769 		VOP_UNLOCK(be_lun->vn);
770 
771 		vn_finished_write(mountpoint);
772 		SDT_PROBE0(cbb, , write, file_done);
773         }
774 
775 	mtx_lock(&be_lun->io_lock);
776 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
777 	    beio->ds_tag_type, beio->ds_trans_type,
778 	    /*now*/ NULL, /*then*/&beio->ds_t0);
779 	mtx_unlock(&be_lun->io_lock);
780 
781 	/*
782 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
783 	 * return the I/O to the user.
784 	 */
785 	if (error != 0) {
786 		if (error == ENOSPC || error == EDQUOT) {
787 			ctl_set_space_alloc_fail(&io->scsiio);
788 		} else if (error == EROFS || error == EACCES) {
789 			ctl_set_hw_write_protected(&io->scsiio);
790 		} else {
791 			ctl_set_medium_error(&io->scsiio,
792 			    beio->bio_cmd == BIO_READ);
793 		}
794 		ctl_complete_beio(beio);
795 		return;
796 	}
797 
798 	/*
799 	 * If this is a write or a verify, we're all done.
800 	 * If this is a read, we can now send the data to the user.
801 	 */
802 	if ((beio->bio_cmd == BIO_WRITE) ||
803 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
804 		ctl_set_success(&io->scsiio);
805 		ctl_complete_beio(beio);
806 	} else {
807 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
808 		    beio->beio_cont == NULL) {
809 			ctl_set_success(&io->scsiio);
810 			ctl_serseq_done(io);
811 		}
812 #ifdef CTL_TIME_IO
813 		getbinuptime(&io->io_hdr.dma_start_bt);
814 #endif
815 		ctl_datamove(io);
816 	}
817 }
818 
819 static void
820 ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
821 			struct ctl_be_block_io *beio)
822 {
823 	union ctl_io *io = beio->io;
824 	struct ctl_lba_len_flags *lbalen = ARGS(io);
825 	struct scsi_get_lba_status_data *data;
826 	off_t roff, off;
827 	int error, status;
828 
829 	DPRINTF("entered\n");
830 
831 	off = roff = ((off_t)lbalen->lba) * be_lun->cbe_lun.blocksize;
832 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
833 	error = VOP_IOCTL(be_lun->vn, FIOSEEKHOLE, &off,
834 	    0, curthread->td_ucred, curthread);
835 	if (error == 0 && off > roff)
836 		status = 0;	/* mapped up to off */
837 	else {
838 		error = VOP_IOCTL(be_lun->vn, FIOSEEKDATA, &off,
839 		    0, curthread->td_ucred, curthread);
840 		if (error == 0 && off > roff)
841 			status = 1;	/* deallocated up to off */
842 		else {
843 			status = 0;	/* unknown up to the end */
844 			off = be_lun->size_bytes;
845 		}
846 	}
847 	VOP_UNLOCK(be_lun->vn);
848 
849 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
850 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
851 	scsi_ulto4b(MIN(UINT32_MAX, off / be_lun->cbe_lun.blocksize -
852 	    lbalen->lba), data->descr[0].length);
853 	data->descr[0].status = status;
854 
855 	ctl_complete_beio(beio);
856 }
857 
858 static uint64_t
859 ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun, const char *attrname)
860 {
861 	struct vattr		vattr;
862 	struct statfs		statfs;
863 	uint64_t		val;
864 	int			error;
865 
866 	val = UINT64_MAX;
867 	if (be_lun->vn == NULL)
868 		return (val);
869 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
870 	if (strcmp(attrname, "blocksused") == 0) {
871 		error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
872 		if (error == 0)
873 			val = vattr.va_bytes / be_lun->cbe_lun.blocksize;
874 	}
875 	if (strcmp(attrname, "blocksavail") == 0 &&
876 	    !VN_IS_DOOMED(be_lun->vn)) {
877 		error = VFS_STATFS(be_lun->vn->v_mount, &statfs);
878 		if (error == 0)
879 			val = statfs.f_bavail * statfs.f_bsize /
880 			    be_lun->cbe_lun.blocksize;
881 	}
882 	VOP_UNLOCK(be_lun->vn);
883 	return (val);
884 }
885 
886 static void
887 ctl_be_block_dispatch_zvol(struct ctl_be_block_lun *be_lun,
888 			   struct ctl_be_block_io *beio)
889 {
890 	union ctl_io *io;
891 	struct cdevsw *csw;
892 	struct cdev *dev;
893 	struct uio xuio;
894 	struct iovec *xiovec;
895 	int error, flags, i, ref;
896 
897 	DPRINTF("entered\n");
898 
899 	io = beio->io;
900 	flags = 0;
901 	if (ARGS(io)->flags & CTL_LLF_DPO)
902 		flags |= IO_DIRECT;
903 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
904 		flags |= IO_SYNC;
905 
906 	bzero(&xuio, sizeof(xuio));
907 	if (beio->bio_cmd == BIO_READ) {
908 		SDT_PROBE0(cbb, , read, file_start);
909 		xuio.uio_rw = UIO_READ;
910 	} else {
911 		SDT_PROBE0(cbb, , write, file_start);
912 		xuio.uio_rw = UIO_WRITE;
913 	}
914 	xuio.uio_offset = beio->io_offset;
915 	xuio.uio_resid = beio->io_len;
916 	xuio.uio_segflg = UIO_SYSSPACE;
917 	xuio.uio_iov = beio->xiovecs;
918 	xuio.uio_iovcnt = beio->num_segs;
919 	xuio.uio_td = curthread;
920 
921 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
922 		xiovec->iov_base = beio->sg_segs[i].addr;
923 		xiovec->iov_len = beio->sg_segs[i].len;
924 	}
925 
926 	binuptime(&beio->ds_t0);
927 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
928 
929 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
930 	if (csw) {
931 		if (beio->bio_cmd == BIO_READ)
932 			error = csw->d_read(dev, &xuio, flags);
933 		else
934 			error = csw->d_write(dev, &xuio, flags);
935 		dev_relthread(dev, ref);
936 	} else
937 		error = ENXIO;
938 
939 	if (beio->bio_cmd == BIO_READ)
940 		SDT_PROBE0(cbb, , read, file_done);
941 	else
942 		SDT_PROBE0(cbb, , write, file_done);
943 
944 	mtx_lock(&be_lun->io_lock);
945 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
946 	    beio->ds_tag_type, beio->ds_trans_type,
947 	    /*now*/ NULL, /*then*/&beio->ds_t0);
948 	mtx_unlock(&be_lun->io_lock);
949 
950 	/*
951 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
952 	 * return the I/O to the user.
953 	 */
954 	if (error != 0) {
955 		if (error == ENOSPC || error == EDQUOT) {
956 			ctl_set_space_alloc_fail(&io->scsiio);
957 		} else if (error == EROFS || error == EACCES) {
958 			ctl_set_hw_write_protected(&io->scsiio);
959 		} else {
960 			ctl_set_medium_error(&io->scsiio,
961 			    beio->bio_cmd == BIO_READ);
962 		}
963 		ctl_complete_beio(beio);
964 		return;
965 	}
966 
967 	/*
968 	 * If this is a write or a verify, we're all done.
969 	 * If this is a read, we can now send the data to the user.
970 	 */
971 	if ((beio->bio_cmd == BIO_WRITE) ||
972 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
973 		ctl_set_success(&io->scsiio);
974 		ctl_complete_beio(beio);
975 	} else {
976 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
977 		    beio->beio_cont == NULL) {
978 			ctl_set_success(&io->scsiio);
979 			ctl_serseq_done(io);
980 		}
981 #ifdef CTL_TIME_IO
982 		getbinuptime(&io->io_hdr.dma_start_bt);
983 #endif
984 		ctl_datamove(io);
985 	}
986 }
987 
988 static void
989 ctl_be_block_gls_zvol(struct ctl_be_block_lun *be_lun,
990 			struct ctl_be_block_io *beio)
991 {
992 	union ctl_io *io = beio->io;
993 	struct cdevsw *csw;
994 	struct cdev *dev;
995 	struct ctl_lba_len_flags *lbalen = ARGS(io);
996 	struct scsi_get_lba_status_data *data;
997 	off_t roff, off;
998 	int error, ref, status;
999 
1000 	DPRINTF("entered\n");
1001 
1002 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1003 	if (csw == NULL) {
1004 		status = 0;	/* unknown up to the end */
1005 		off = be_lun->size_bytes;
1006 		goto done;
1007 	}
1008 	off = roff = ((off_t)lbalen->lba) * be_lun->cbe_lun.blocksize;
1009 	error = csw->d_ioctl(dev, FIOSEEKHOLE, (caddr_t)&off, FREAD,
1010 	    curthread);
1011 	if (error == 0 && off > roff)
1012 		status = 0;	/* mapped up to off */
1013 	else {
1014 		error = csw->d_ioctl(dev, FIOSEEKDATA, (caddr_t)&off, FREAD,
1015 		    curthread);
1016 		if (error == 0 && off > roff)
1017 			status = 1;	/* deallocated up to off */
1018 		else {
1019 			status = 0;	/* unknown up to the end */
1020 			off = be_lun->size_bytes;
1021 		}
1022 	}
1023 	dev_relthread(dev, ref);
1024 
1025 done:
1026 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
1027 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
1028 	scsi_ulto4b(MIN(UINT32_MAX, off / be_lun->cbe_lun.blocksize -
1029 	    lbalen->lba), data->descr[0].length);
1030 	data->descr[0].status = status;
1031 
1032 	ctl_complete_beio(beio);
1033 }
1034 
1035 static void
1036 ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
1037 		       struct ctl_be_block_io *beio)
1038 {
1039 	struct bio *bio;
1040 	struct cdevsw *csw;
1041 	struct cdev *dev;
1042 	int ref;
1043 
1044 	DPRINTF("entered\n");
1045 
1046 	/* This can't fail, it's a blocking allocation. */
1047 	bio = g_alloc_bio();
1048 
1049 	bio->bio_cmd	    = BIO_FLUSH;
1050 	bio->bio_offset	    = 0;
1051 	bio->bio_data	    = 0;
1052 	bio->bio_done	    = ctl_be_block_biodone;
1053 	bio->bio_caller1    = beio;
1054 	bio->bio_pblkno	    = 0;
1055 
1056 	/*
1057 	 * We don't need to acquire the LUN lock here, because we are only
1058 	 * sending one bio, and so there is no other context to synchronize
1059 	 * with.
1060 	 */
1061 	beio->num_bios_sent = 1;
1062 	beio->send_complete = 1;
1063 
1064 	binuptime(&beio->ds_t0);
1065 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1066 
1067 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1068 	if (csw) {
1069 		bio->bio_dev = dev;
1070 		csw->d_strategy(bio);
1071 		dev_relthread(dev, ref);
1072 	} else {
1073 		bio->bio_error = ENXIO;
1074 		ctl_be_block_biodone(bio);
1075 	}
1076 }
1077 
1078 static void
1079 ctl_be_block_unmap_dev_range(struct ctl_be_block_lun *be_lun,
1080 		       struct ctl_be_block_io *beio,
1081 		       uint64_t off, uint64_t len, int last)
1082 {
1083 	struct bio *bio;
1084 	uint64_t maxlen;
1085 	struct cdevsw *csw;
1086 	struct cdev *dev;
1087 	int ref;
1088 
1089 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1090 	maxlen = LONG_MAX - (LONG_MAX % be_lun->cbe_lun.blocksize);
1091 	while (len > 0) {
1092 		bio = g_alloc_bio();
1093 		bio->bio_cmd	    = BIO_DELETE;
1094 		bio->bio_dev	    = dev;
1095 		bio->bio_offset	    = off;
1096 		bio->bio_length	    = MIN(len, maxlen);
1097 		bio->bio_data	    = 0;
1098 		bio->bio_done	    = ctl_be_block_biodone;
1099 		bio->bio_caller1    = beio;
1100 		bio->bio_pblkno     = off / be_lun->cbe_lun.blocksize;
1101 
1102 		off += bio->bio_length;
1103 		len -= bio->bio_length;
1104 
1105 		mtx_lock(&be_lun->io_lock);
1106 		beio->num_bios_sent++;
1107 		if (last && len == 0)
1108 			beio->send_complete = 1;
1109 		mtx_unlock(&be_lun->io_lock);
1110 
1111 		if (csw) {
1112 			csw->d_strategy(bio);
1113 		} else {
1114 			bio->bio_error = ENXIO;
1115 			ctl_be_block_biodone(bio);
1116 		}
1117 	}
1118 	if (csw)
1119 		dev_relthread(dev, ref);
1120 }
1121 
1122 static void
1123 ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
1124 		       struct ctl_be_block_io *beio)
1125 {
1126 	union ctl_io *io;
1127 	struct ctl_ptr_len_flags *ptrlen;
1128 	struct scsi_unmap_desc *buf, *end;
1129 	uint64_t len;
1130 
1131 	io = beio->io;
1132 
1133 	DPRINTF("entered\n");
1134 
1135 	binuptime(&beio->ds_t0);
1136 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1137 
1138 	if (beio->io_offset == -1) {
1139 		beio->io_len = 0;
1140 		ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1141 		buf = (struct scsi_unmap_desc *)ptrlen->ptr;
1142 		end = buf + ptrlen->len / sizeof(*buf);
1143 		for (; buf < end; buf++) {
1144 			len = (uint64_t)scsi_4btoul(buf->length) *
1145 			    be_lun->cbe_lun.blocksize;
1146 			beio->io_len += len;
1147 			ctl_be_block_unmap_dev_range(be_lun, beio,
1148 			    scsi_8btou64(buf->lba) * be_lun->cbe_lun.blocksize,
1149 			    len, (end - buf < 2) ? TRUE : FALSE);
1150 		}
1151 	} else
1152 		ctl_be_block_unmap_dev_range(be_lun, beio,
1153 		    beio->io_offset, beio->io_len, TRUE);
1154 }
1155 
1156 static void
1157 ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
1158 			  struct ctl_be_block_io *beio)
1159 {
1160 	TAILQ_HEAD(, bio) queue = TAILQ_HEAD_INITIALIZER(queue);
1161 	struct bio *bio;
1162 	struct cdevsw *csw;
1163 	struct cdev *dev;
1164 	off_t cur_offset;
1165 	int i, max_iosize, ref;
1166 
1167 	DPRINTF("entered\n");
1168 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1169 
1170 	/*
1171 	 * We have to limit our I/O size to the maximum supported by the
1172 	 * backend device.
1173 	 */
1174 	if (csw) {
1175 		max_iosize = dev->si_iosize_max;
1176 		if (max_iosize < PAGE_SIZE)
1177 			max_iosize = DFLTPHYS;
1178 	} else
1179 		max_iosize = DFLTPHYS;
1180 
1181 	cur_offset = beio->io_offset;
1182 	for (i = 0; i < beio->num_segs; i++) {
1183 		size_t cur_size;
1184 		uint8_t *cur_ptr;
1185 
1186 		cur_size = beio->sg_segs[i].len;
1187 		cur_ptr = beio->sg_segs[i].addr;
1188 
1189 		while (cur_size > 0) {
1190 			/* This can't fail, it's a blocking allocation. */
1191 			bio = g_alloc_bio();
1192 
1193 			KASSERT(bio != NULL, ("g_alloc_bio() failed!\n"));
1194 
1195 			bio->bio_cmd = beio->bio_cmd;
1196 			bio->bio_dev = dev;
1197 			bio->bio_caller1 = beio;
1198 			bio->bio_length = min(cur_size, max_iosize);
1199 			bio->bio_offset = cur_offset;
1200 			bio->bio_data = cur_ptr;
1201 			bio->bio_done = ctl_be_block_biodone;
1202 			bio->bio_pblkno = cur_offset / be_lun->cbe_lun.blocksize;
1203 
1204 			cur_offset += bio->bio_length;
1205 			cur_ptr += bio->bio_length;
1206 			cur_size -= bio->bio_length;
1207 
1208 			TAILQ_INSERT_TAIL(&queue, bio, bio_queue);
1209 			beio->num_bios_sent++;
1210 		}
1211 	}
1212 	beio->send_complete = 1;
1213 	binuptime(&beio->ds_t0);
1214 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1215 
1216 	/*
1217 	 * Fire off all allocated requests!
1218 	 */
1219 	while ((bio = TAILQ_FIRST(&queue)) != NULL) {
1220 		TAILQ_REMOVE(&queue, bio, bio_queue);
1221 		if (csw)
1222 			csw->d_strategy(bio);
1223 		else {
1224 			bio->bio_error = ENXIO;
1225 			ctl_be_block_biodone(bio);
1226 		}
1227 	}
1228 	if (csw)
1229 		dev_relthread(dev, ref);
1230 }
1231 
1232 static uint64_t
1233 ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun, const char *attrname)
1234 {
1235 	struct diocgattr_arg	arg;
1236 	struct cdevsw *csw;
1237 	struct cdev *dev;
1238 	int error, ref;
1239 
1240 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1241 	if (csw == NULL)
1242 		return (UINT64_MAX);
1243 	strlcpy(arg.name, attrname, sizeof(arg.name));
1244 	arg.len = sizeof(arg.value.off);
1245 	if (csw->d_ioctl) {
1246 		error = csw->d_ioctl(dev, DIOCGATTR, (caddr_t)&arg, FREAD,
1247 		    curthread);
1248 	} else
1249 		error = ENODEV;
1250 	dev_relthread(dev, ref);
1251 	if (error != 0)
1252 		return (UINT64_MAX);
1253 	return (arg.value.off);
1254 }
1255 
1256 static void
1257 ctl_be_block_cw_dispatch_sync(struct ctl_be_block_lun *be_lun,
1258 			    union ctl_io *io)
1259 {
1260 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1261 	struct ctl_be_block_io *beio;
1262 	struct ctl_lba_len_flags *lbalen;
1263 
1264 	DPRINTF("entered\n");
1265 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1266 	lbalen = (struct ctl_lba_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1267 
1268 	beio->io_len = lbalen->len * cbe_lun->blocksize;
1269 	beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1270 	beio->io_arg = (lbalen->flags & SSC_IMMED) != 0;
1271 	beio->bio_cmd = BIO_FLUSH;
1272 	beio->ds_trans_type = DEVSTAT_NO_DATA;
1273 	DPRINTF("SYNC\n");
1274 	be_lun->lun_flush(be_lun, beio);
1275 }
1276 
1277 static void
1278 ctl_be_block_cw_done_ws(struct ctl_be_block_io *beio)
1279 {
1280 	union ctl_io *io;
1281 
1282 	io = beio->io;
1283 	ctl_free_beio(beio);
1284 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1285 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1286 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1287 		ctl_config_write_done(io);
1288 		return;
1289 	}
1290 
1291 	ctl_be_block_config_write(io);
1292 }
1293 
1294 static void
1295 ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
1296 			    union ctl_io *io)
1297 {
1298 	struct ctl_be_block_softc *softc = be_lun->softc;
1299 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1300 	struct ctl_be_block_io *beio;
1301 	struct ctl_lba_len_flags *lbalen;
1302 	uint64_t len_left, lba;
1303 	uint32_t pb, pbo, adj;
1304 	int i, seglen;
1305 	uint8_t *buf, *end;
1306 
1307 	DPRINTF("entered\n");
1308 
1309 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1310 	lbalen = ARGS(beio->io);
1311 
1312 	if (lbalen->flags & ~(SWS_LBDATA | SWS_UNMAP | SWS_ANCHOR | SWS_NDOB) ||
1313 	    (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR) && be_lun->unmap == NULL)) {
1314 		ctl_free_beio(beio);
1315 		ctl_set_invalid_field(&io->scsiio,
1316 				      /*sks_valid*/ 1,
1317 				      /*command*/ 1,
1318 				      /*field*/ 1,
1319 				      /*bit_valid*/ 0,
1320 				      /*bit*/ 0);
1321 		ctl_config_write_done(io);
1322 		return;
1323 	}
1324 
1325 	if (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR)) {
1326 		beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1327 		beio->io_len = (uint64_t)lbalen->len * cbe_lun->blocksize;
1328 		beio->bio_cmd = BIO_DELETE;
1329 		beio->ds_trans_type = DEVSTAT_FREE;
1330 
1331 		be_lun->unmap(be_lun, beio);
1332 		return;
1333 	}
1334 
1335 	beio->bio_cmd = BIO_WRITE;
1336 	beio->ds_trans_type = DEVSTAT_WRITE;
1337 
1338 	DPRINTF("WRITE SAME at LBA %jx len %u\n",
1339 	       (uintmax_t)lbalen->lba, lbalen->len);
1340 
1341 	pb = cbe_lun->blocksize << be_lun->cbe_lun.pblockexp;
1342 	if (be_lun->cbe_lun.pblockoff > 0)
1343 		pbo = pb - cbe_lun->blocksize * be_lun->cbe_lun.pblockoff;
1344 	else
1345 		pbo = 0;
1346 	len_left = (uint64_t)lbalen->len * cbe_lun->blocksize;
1347 	for (i = 0, lba = 0; i < CTLBLK_MAX_SEGS && len_left > 0; i++) {
1348 		/*
1349 		 * Setup the S/G entry for this chunk.
1350 		 */
1351 		seglen = MIN(CTLBLK_MAX_SEG, len_left);
1352 		if (pb > cbe_lun->blocksize) {
1353 			adj = ((lbalen->lba + lba) * cbe_lun->blocksize +
1354 			    seglen - pbo) % pb;
1355 			if (seglen > adj)
1356 				seglen -= adj;
1357 			else
1358 				seglen -= seglen % cbe_lun->blocksize;
1359 		} else
1360 			seglen -= seglen % cbe_lun->blocksize;
1361 		ctl_alloc_seg(softc, &beio->sg_segs[i], seglen);
1362 
1363 		DPRINTF("segment %d addr %p len %zd\n", i,
1364 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1365 
1366 		beio->num_segs++;
1367 		len_left -= seglen;
1368 
1369 		buf = beio->sg_segs[i].addr;
1370 		end = buf + seglen;
1371 		for (; buf < end; buf += cbe_lun->blocksize) {
1372 			if (lbalen->flags & SWS_NDOB) {
1373 				memset(buf, 0, cbe_lun->blocksize);
1374 			} else {
1375 				memcpy(buf, io->scsiio.kern_data_ptr,
1376 				    cbe_lun->blocksize);
1377 			}
1378 			if (lbalen->flags & SWS_LBDATA)
1379 				scsi_ulto4b(lbalen->lba + lba, buf);
1380 			lba++;
1381 		}
1382 	}
1383 
1384 	beio->io_offset = lbalen->lba * cbe_lun->blocksize;
1385 	beio->io_len = lba * cbe_lun->blocksize;
1386 
1387 	/* We can not do all in one run. Correct and schedule rerun. */
1388 	if (len_left > 0) {
1389 		lbalen->lba += lba;
1390 		lbalen->len -= lba;
1391 		beio->beio_cont = ctl_be_block_cw_done_ws;
1392 	}
1393 
1394 	be_lun->dispatch(be_lun, beio);
1395 }
1396 
1397 static void
1398 ctl_be_block_cw_dispatch_unmap(struct ctl_be_block_lun *be_lun,
1399 			    union ctl_io *io)
1400 {
1401 	struct ctl_be_block_io *beio;
1402 	struct ctl_ptr_len_flags *ptrlen;
1403 
1404 	DPRINTF("entered\n");
1405 
1406 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1407 	ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1408 
1409 	if ((ptrlen->flags & ~SU_ANCHOR) != 0 || be_lun->unmap == NULL) {
1410 		ctl_free_beio(beio);
1411 		ctl_set_invalid_field(&io->scsiio,
1412 				      /*sks_valid*/ 0,
1413 				      /*command*/ 1,
1414 				      /*field*/ 0,
1415 				      /*bit_valid*/ 0,
1416 				      /*bit*/ 0);
1417 		ctl_config_write_done(io);
1418 		return;
1419 	}
1420 
1421 	beio->io_len = 0;
1422 	beio->io_offset = -1;
1423 	beio->bio_cmd = BIO_DELETE;
1424 	beio->ds_trans_type = DEVSTAT_FREE;
1425 	DPRINTF("UNMAP\n");
1426 	be_lun->unmap(be_lun, beio);
1427 }
1428 
1429 static void
1430 ctl_be_block_cr_done(struct ctl_be_block_io *beio)
1431 {
1432 	union ctl_io *io;
1433 
1434 	io = beio->io;
1435 	ctl_free_beio(beio);
1436 	ctl_config_read_done(io);
1437 }
1438 
1439 static void
1440 ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
1441 			 union ctl_io *io)
1442 {
1443 	struct ctl_be_block_io *beio;
1444 	struct ctl_be_block_softc *softc;
1445 
1446 	DPRINTF("entered\n");
1447 
1448 	softc = be_lun->softc;
1449 	beio = ctl_alloc_beio(softc);
1450 	beio->io = io;
1451 	beio->lun = be_lun;
1452 	beio->beio_cont = ctl_be_block_cr_done;
1453 	PRIV(io)->ptr = (void *)beio;
1454 
1455 	switch (io->scsiio.cdb[0]) {
1456 	case SERVICE_ACTION_IN:		/* GET LBA STATUS */
1457 		beio->bio_cmd = -1;
1458 		beio->ds_trans_type = DEVSTAT_NO_DATA;
1459 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1460 		beio->io_len = 0;
1461 		if (be_lun->get_lba_status)
1462 			be_lun->get_lba_status(be_lun, beio);
1463 		else
1464 			ctl_be_block_cr_done(beio);
1465 		break;
1466 	default:
1467 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1468 		break;
1469 	}
1470 }
1471 
1472 static void
1473 ctl_be_block_cw_done(struct ctl_be_block_io *beio)
1474 {
1475 	union ctl_io *io;
1476 
1477 	io = beio->io;
1478 	ctl_free_beio(beio);
1479 	ctl_config_write_done(io);
1480 }
1481 
1482 static void
1483 ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
1484 			 union ctl_io *io)
1485 {
1486 	struct ctl_be_block_io *beio;
1487 	struct ctl_be_block_softc *softc;
1488 
1489 	DPRINTF("entered\n");
1490 
1491 	softc = be_lun->softc;
1492 	beio = ctl_alloc_beio(softc);
1493 	beio->io = io;
1494 	beio->lun = be_lun;
1495 	beio->beio_cont = ctl_be_block_cw_done;
1496 	switch (io->scsiio.tag_type) {
1497 	case CTL_TAG_ORDERED:
1498 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1499 		break;
1500 	case CTL_TAG_HEAD_OF_QUEUE:
1501 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1502 		break;
1503 	case CTL_TAG_UNTAGGED:
1504 	case CTL_TAG_SIMPLE:
1505 	case CTL_TAG_ACA:
1506 	default:
1507 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1508 		break;
1509 	}
1510 	PRIV(io)->ptr = (void *)beio;
1511 
1512 	switch (io->scsiio.cdb[0]) {
1513 	case SYNCHRONIZE_CACHE:
1514 	case SYNCHRONIZE_CACHE_16:
1515 		ctl_be_block_cw_dispatch_sync(be_lun, io);
1516 		break;
1517 	case WRITE_SAME_10:
1518 	case WRITE_SAME_16:
1519 		ctl_be_block_cw_dispatch_ws(be_lun, io);
1520 		break;
1521 	case UNMAP:
1522 		ctl_be_block_cw_dispatch_unmap(be_lun, io);
1523 		break;
1524 	default:
1525 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1526 		break;
1527 	}
1528 }
1529 
1530 SDT_PROBE_DEFINE1(cbb, , read, start, "uint64_t");
1531 SDT_PROBE_DEFINE1(cbb, , write, start, "uint64_t");
1532 SDT_PROBE_DEFINE1(cbb, , read, alloc_done, "uint64_t");
1533 SDT_PROBE_DEFINE1(cbb, , write, alloc_done, "uint64_t");
1534 
1535 static void
1536 ctl_be_block_next(struct ctl_be_block_io *beio)
1537 {
1538 	struct ctl_be_block_lun *be_lun;
1539 	union ctl_io *io;
1540 
1541 	io = beio->io;
1542 	be_lun = beio->lun;
1543 	ctl_free_beio(beio);
1544 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1545 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1546 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1547 		ctl_data_submit_done(io);
1548 		return;
1549 	}
1550 
1551 	io->io_hdr.status &= ~CTL_STATUS_MASK;
1552 	io->io_hdr.status |= CTL_STATUS_NONE;
1553 
1554 	mtx_lock(&be_lun->queue_lock);
1555 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1556 	mtx_unlock(&be_lun->queue_lock);
1557 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1558 }
1559 
1560 static void
1561 ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
1562 			   union ctl_io *io)
1563 {
1564 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1565 	struct ctl_be_block_io *beio;
1566 	struct ctl_be_block_softc *softc;
1567 	struct ctl_lba_len_flags *lbalen;
1568 	struct ctl_ptr_len_flags *bptrlen;
1569 	uint64_t len_left, lbas;
1570 	int i;
1571 
1572 	softc = be_lun->softc;
1573 
1574 	DPRINTF("entered\n");
1575 
1576 	lbalen = ARGS(io);
1577 	if (lbalen->flags & CTL_LLF_WRITE) {
1578 		SDT_PROBE0(cbb, , write, start);
1579 	} else {
1580 		SDT_PROBE0(cbb, , read, start);
1581 	}
1582 
1583 	beio = ctl_alloc_beio(softc);
1584 	beio->io = io;
1585 	beio->lun = be_lun;
1586 	bptrlen = PRIV(io);
1587 	bptrlen->ptr = (void *)beio;
1588 
1589 	switch (io->scsiio.tag_type) {
1590 	case CTL_TAG_ORDERED:
1591 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1592 		break;
1593 	case CTL_TAG_HEAD_OF_QUEUE:
1594 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1595 		break;
1596 	case CTL_TAG_UNTAGGED:
1597 	case CTL_TAG_SIMPLE:
1598 	case CTL_TAG_ACA:
1599 	default:
1600 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1601 		break;
1602 	}
1603 
1604 	if (lbalen->flags & CTL_LLF_WRITE) {
1605 		beio->bio_cmd = BIO_WRITE;
1606 		beio->ds_trans_type = DEVSTAT_WRITE;
1607 	} else {
1608 		beio->bio_cmd = BIO_READ;
1609 		beio->ds_trans_type = DEVSTAT_READ;
1610 	}
1611 
1612 	DPRINTF("%s at LBA %jx len %u @%ju\n",
1613 	       (beio->bio_cmd == BIO_READ) ? "READ" : "WRITE",
1614 	       (uintmax_t)lbalen->lba, lbalen->len, bptrlen->len);
1615 	if (lbalen->flags & CTL_LLF_COMPARE) {
1616 		beio->two_sglists = 1;
1617 		lbas = CTLBLK_HALF_IO_SIZE;
1618 	} else {
1619 		lbas = CTLBLK_MAX_IO_SIZE;
1620 	}
1621 	lbas = MIN(lbalen->len - bptrlen->len, lbas / cbe_lun->blocksize);
1622 	beio->io_offset = (lbalen->lba + bptrlen->len) * cbe_lun->blocksize;
1623 	beio->io_len = lbas * cbe_lun->blocksize;
1624 	bptrlen->len += lbas;
1625 
1626 	for (i = 0, len_left = beio->io_len; len_left > 0; i++) {
1627 		KASSERT(i < CTLBLK_MAX_SEGS, ("Too many segs (%d >= %d)",
1628 		    i, CTLBLK_MAX_SEGS));
1629 
1630 		/*
1631 		 * Setup the S/G entry for this chunk.
1632 		 */
1633 		ctl_alloc_seg(softc, &beio->sg_segs[i],
1634 		    min(CTLBLK_MAX_SEG, len_left));
1635 
1636 		DPRINTF("segment %d addr %p len %zd\n", i,
1637 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1638 
1639 		/* Set up second segment for compare operation. */
1640 		if (beio->two_sglists) {
1641 			ctl_alloc_seg(softc,
1642 			    &beio->sg_segs[i + CTLBLK_HALF_SEGS],
1643 			    beio->sg_segs[i].len);
1644 		}
1645 
1646 		beio->num_segs++;
1647 		len_left -= beio->sg_segs[i].len;
1648 	}
1649 	if (bptrlen->len < lbalen->len)
1650 		beio->beio_cont = ctl_be_block_next;
1651 	io->scsiio.be_move_done = ctl_be_block_move_done;
1652 	/* For compare we have separate S/G lists for read and datamove. */
1653 	if (beio->two_sglists)
1654 		io->scsiio.kern_data_ptr = (uint8_t *)&beio->sg_segs[CTLBLK_HALF_SEGS];
1655 	else
1656 		io->scsiio.kern_data_ptr = (uint8_t *)beio->sg_segs;
1657 	io->scsiio.kern_data_len = beio->io_len;
1658 	io->scsiio.kern_sg_entries = beio->num_segs;
1659 	io->scsiio.kern_data_ref = ctl_refcnt_beio;
1660 	io->scsiio.kern_data_arg = beio;
1661 	io->io_hdr.flags |= CTL_FLAG_ALLOCATED;
1662 
1663 	/*
1664 	 * For the read case, we need to read the data into our buffers and
1665 	 * then we can send it back to the user.  For the write case, we
1666 	 * need to get the data from the user first.
1667 	 */
1668 	if (beio->bio_cmd == BIO_READ) {
1669 		SDT_PROBE0(cbb, , read, alloc_done);
1670 		be_lun->dispatch(be_lun, beio);
1671 	} else {
1672 		SDT_PROBE0(cbb, , write, alloc_done);
1673 #ifdef CTL_TIME_IO
1674 		getbinuptime(&io->io_hdr.dma_start_bt);
1675 #endif
1676 		ctl_datamove(io);
1677 	}
1678 }
1679 
1680 static void
1681 ctl_be_block_worker(void *context, int pending)
1682 {
1683 	struct ctl_be_block_lun *be_lun = (struct ctl_be_block_lun *)context;
1684 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1685 	union ctl_io *io;
1686 	struct ctl_be_block_io *beio;
1687 
1688 	DPRINTF("entered\n");
1689 	/*
1690 	 * Fetch and process I/Os from all queues.  If we detect LUN
1691 	 * CTL_LUN_FLAG_NO_MEDIA status here -- it is result of a race,
1692 	 * so make response maximally opaque to not confuse initiator.
1693 	 */
1694 	for (;;) {
1695 		mtx_lock(&be_lun->queue_lock);
1696 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->datamove_queue);
1697 		if (io != NULL) {
1698 			DPRINTF("datamove queue\n");
1699 			STAILQ_REMOVE(&be_lun->datamove_queue, &io->io_hdr,
1700 				      ctl_io_hdr, links);
1701 			mtx_unlock(&be_lun->queue_lock);
1702 			beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1703 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1704 				ctl_set_busy(&io->scsiio);
1705 				ctl_complete_beio(beio);
1706 				return;
1707 			}
1708 			be_lun->dispatch(be_lun, beio);
1709 			continue;
1710 		}
1711 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_write_queue);
1712 		if (io != NULL) {
1713 			DPRINTF("config write queue\n");
1714 			STAILQ_REMOVE(&be_lun->config_write_queue, &io->io_hdr,
1715 				      ctl_io_hdr, links);
1716 			mtx_unlock(&be_lun->queue_lock);
1717 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1718 				ctl_set_busy(&io->scsiio);
1719 				ctl_config_write_done(io);
1720 				return;
1721 			}
1722 			ctl_be_block_cw_dispatch(be_lun, io);
1723 			continue;
1724 		}
1725 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_read_queue);
1726 		if (io != NULL) {
1727 			DPRINTF("config read queue\n");
1728 			STAILQ_REMOVE(&be_lun->config_read_queue, &io->io_hdr,
1729 				      ctl_io_hdr, links);
1730 			mtx_unlock(&be_lun->queue_lock);
1731 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1732 				ctl_set_busy(&io->scsiio);
1733 				ctl_config_read_done(io);
1734 				return;
1735 			}
1736 			ctl_be_block_cr_dispatch(be_lun, io);
1737 			continue;
1738 		}
1739 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->input_queue);
1740 		if (io != NULL) {
1741 			DPRINTF("input queue\n");
1742 			STAILQ_REMOVE(&be_lun->input_queue, &io->io_hdr,
1743 				      ctl_io_hdr, links);
1744 			mtx_unlock(&be_lun->queue_lock);
1745 			if (cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) {
1746 				ctl_set_busy(&io->scsiio);
1747 				ctl_data_submit_done(io);
1748 				return;
1749 			}
1750 			ctl_be_block_dispatch(be_lun, io);
1751 			continue;
1752 		}
1753 
1754 		/*
1755 		 * If we get here, there is no work left in the queues, so
1756 		 * just break out and let the task queue go to sleep.
1757 		 */
1758 		mtx_unlock(&be_lun->queue_lock);
1759 		break;
1760 	}
1761 }
1762 
1763 /*
1764  * Entry point from CTL to the backend for I/O.  We queue everything to a
1765  * work thread, so this just puts the I/O on a queue and wakes up the
1766  * thread.
1767  */
1768 static int
1769 ctl_be_block_submit(union ctl_io *io)
1770 {
1771 	struct ctl_be_block_lun *be_lun;
1772 
1773 	DPRINTF("entered\n");
1774 
1775 	be_lun = (struct ctl_be_block_lun *)CTL_BACKEND_LUN(io);
1776 
1777 	/*
1778 	 * Make sure we only get SCSI I/O.
1779 	 */
1780 	KASSERT(io->io_hdr.io_type == CTL_IO_SCSI, ("Non-SCSI I/O (type "
1781 		"%#x) encountered", io->io_hdr.io_type));
1782 
1783 	PRIV(io)->len = 0;
1784 
1785 	mtx_lock(&be_lun->queue_lock);
1786 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1787 	mtx_unlock(&be_lun->queue_lock);
1788 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1789 
1790 	return (CTL_RETVAL_COMPLETE);
1791 }
1792 
1793 static int
1794 ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
1795 			int flag, struct thread *td)
1796 {
1797 	struct ctl_be_block_softc *softc = &backend_block_softc;
1798 	int error;
1799 
1800 	error = 0;
1801 	switch (cmd) {
1802 	case CTL_LUN_REQ: {
1803 		struct ctl_lun_req *lun_req;
1804 
1805 		lun_req = (struct ctl_lun_req *)addr;
1806 
1807 		switch (lun_req->reqtype) {
1808 		case CTL_LUNREQ_CREATE:
1809 			error = ctl_be_block_create(softc, lun_req);
1810 			break;
1811 		case CTL_LUNREQ_RM:
1812 			error = ctl_be_block_rm(softc, lun_req);
1813 			break;
1814 		case CTL_LUNREQ_MODIFY:
1815 			error = ctl_be_block_modify(softc, lun_req);
1816 			break;
1817 		default:
1818 			lun_req->status = CTL_LUN_ERROR;
1819 			snprintf(lun_req->error_str, sizeof(lun_req->error_str),
1820 				 "invalid LUN request type %d",
1821 				 lun_req->reqtype);
1822 			break;
1823 		}
1824 		break;
1825 	}
1826 	default:
1827 		error = ENOTTY;
1828 		break;
1829 	}
1830 
1831 	return (error);
1832 }
1833 
1834 static int
1835 ctl_be_block_open_file(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1836 {
1837 	struct ctl_be_lun *cbe_lun;
1838 	struct ctl_be_block_filedata *file_data;
1839 	struct ctl_lun_create_params *params;
1840 	const char		     *value;
1841 	struct vattr		      vattr;
1842 	off_t			      ps, pss, po, pos, us, uss, uo, uos;
1843 	int			      error;
1844 
1845 	cbe_lun = &be_lun->cbe_lun;
1846 	file_data = &be_lun->backend.file;
1847 	params = &be_lun->params;
1848 
1849 	be_lun->dev_type = CTL_BE_BLOCK_FILE;
1850 	be_lun->dispatch = ctl_be_block_dispatch_file;
1851 	be_lun->lun_flush = ctl_be_block_flush_file;
1852 	be_lun->get_lba_status = ctl_be_block_gls_file;
1853 	be_lun->getattr = ctl_be_block_getattr_file;
1854 	be_lun->unmap = NULL;
1855 	cbe_lun->flags &= ~CTL_LUN_FLAG_UNMAP;
1856 
1857 	error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
1858 	if (error != 0) {
1859 		snprintf(req->error_str, sizeof(req->error_str),
1860 			 "error calling VOP_GETATTR() for file %s",
1861 			 be_lun->dev_path);
1862 		return (error);
1863 	}
1864 
1865 	file_data->cred = crhold(curthread->td_ucred);
1866 	if (params->lun_size_bytes != 0)
1867 		be_lun->size_bytes = params->lun_size_bytes;
1868 	else
1869 		be_lun->size_bytes = vattr.va_size;
1870 
1871 	/*
1872 	 * For files we can use any logical block size.  Prefer 512 bytes
1873 	 * for compatibility reasons.  If file's vattr.va_blocksize
1874 	 * (preferred I/O block size) is bigger and multiple to chosen
1875 	 * logical block size -- report it as physical block size.
1876 	 */
1877 	if (params->blocksize_bytes != 0)
1878 		cbe_lun->blocksize = params->blocksize_bytes;
1879 	else if (cbe_lun->lun_type == T_CDROM)
1880 		cbe_lun->blocksize = 2048;
1881 	else
1882 		cbe_lun->blocksize = 512;
1883 	be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
1884 	cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
1885 	    0 : (be_lun->size_blocks - 1);
1886 
1887 	us = ps = vattr.va_blocksize;
1888 	uo = po = 0;
1889 
1890 	value = dnvlist_get_string(cbe_lun->options, "pblocksize", NULL);
1891 	if (value != NULL)
1892 		ctl_expand_number(value, &ps);
1893 	value = dnvlist_get_string(cbe_lun->options, "pblockoffset", NULL);
1894 	if (value != NULL)
1895 		ctl_expand_number(value, &po);
1896 	pss = ps / cbe_lun->blocksize;
1897 	pos = po / cbe_lun->blocksize;
1898 	if ((pss > 0) && (pss * cbe_lun->blocksize == ps) && (pss >= pos) &&
1899 	    ((pss & (pss - 1)) == 0) && (pos * cbe_lun->blocksize == po)) {
1900 		cbe_lun->pblockexp = fls(pss) - 1;
1901 		cbe_lun->pblockoff = (pss - pos) % pss;
1902 	}
1903 
1904 	value = dnvlist_get_string(cbe_lun->options, "ublocksize", NULL);
1905 	if (value != NULL)
1906 		ctl_expand_number(value, &us);
1907 	value = dnvlist_get_string(cbe_lun->options, "ublockoffset", NULL);
1908 	if (value != NULL)
1909 		ctl_expand_number(value, &uo);
1910 	uss = us / cbe_lun->blocksize;
1911 	uos = uo / cbe_lun->blocksize;
1912 	if ((uss > 0) && (uss * cbe_lun->blocksize == us) && (uss >= uos) &&
1913 	    ((uss & (uss - 1)) == 0) && (uos * cbe_lun->blocksize == uo)) {
1914 		cbe_lun->ublockexp = fls(uss) - 1;
1915 		cbe_lun->ublockoff = (uss - uos) % uss;
1916 	}
1917 
1918 	/*
1919 	 * Sanity check.  The media size has to be at least one
1920 	 * sector long.
1921 	 */
1922 	if (be_lun->size_bytes < cbe_lun->blocksize) {
1923 		error = EINVAL;
1924 		snprintf(req->error_str, sizeof(req->error_str),
1925 			 "file %s size %ju < block size %u", be_lun->dev_path,
1926 			 (uintmax_t)be_lun->size_bytes, cbe_lun->blocksize);
1927 	}
1928 
1929 	cbe_lun->opttxferlen = CTLBLK_MAX_IO_SIZE / cbe_lun->blocksize;
1930 	return (error);
1931 }
1932 
1933 static int
1934 ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1935 {
1936 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
1937 	struct ctl_lun_create_params *params;
1938 	struct cdevsw		     *csw;
1939 	struct cdev		     *dev;
1940 	const char		     *value;
1941 	int			      error, atomic, maxio, ref, unmap, tmp;
1942 	off_t			      ps, pss, po, pos, us, uss, uo, uos, otmp;
1943 
1944 	params = &be_lun->params;
1945 
1946 	be_lun->dev_type = CTL_BE_BLOCK_DEV;
1947 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
1948 	if (csw == NULL)
1949 		return (ENXIO);
1950 	if (strcmp(csw->d_name, "zvol") == 0) {
1951 		be_lun->dispatch = ctl_be_block_dispatch_zvol;
1952 		be_lun->get_lba_status = ctl_be_block_gls_zvol;
1953 		atomic = maxio = CTLBLK_MAX_IO_SIZE;
1954 	} else {
1955 		be_lun->dispatch = ctl_be_block_dispatch_dev;
1956 		be_lun->get_lba_status = NULL;
1957 		atomic = 0;
1958 		maxio = dev->si_iosize_max;
1959 		if (maxio <= 0)
1960 			maxio = DFLTPHYS;
1961 		if (maxio > CTLBLK_MAX_SEG)
1962 			maxio = CTLBLK_MAX_SEG;
1963 	}
1964 	be_lun->lun_flush = ctl_be_block_flush_dev;
1965 	be_lun->getattr = ctl_be_block_getattr_dev;
1966 	be_lun->unmap = ctl_be_block_unmap_dev;
1967 
1968 	if (!csw->d_ioctl) {
1969 		dev_relthread(dev, ref);
1970 		snprintf(req->error_str, sizeof(req->error_str),
1971 			 "no d_ioctl for device %s!", be_lun->dev_path);
1972 		return (ENODEV);
1973 	}
1974 
1975 	error = csw->d_ioctl(dev, DIOCGSECTORSIZE, (caddr_t)&tmp, FREAD,
1976 			       curthread);
1977 	if (error) {
1978 		dev_relthread(dev, ref);
1979 		snprintf(req->error_str, sizeof(req->error_str),
1980 			 "error %d returned for DIOCGSECTORSIZE ioctl "
1981 			 "on %s!", error, be_lun->dev_path);
1982 		return (error);
1983 	}
1984 
1985 	/*
1986 	 * If the user has asked for a blocksize that is greater than the
1987 	 * backing device's blocksize, we can do it only if the blocksize
1988 	 * the user is asking for is an even multiple of the underlying
1989 	 * device's blocksize.
1990 	 */
1991 	if ((params->blocksize_bytes != 0) &&
1992 	    (params->blocksize_bytes >= tmp)) {
1993 		if (params->blocksize_bytes % tmp == 0) {
1994 			cbe_lun->blocksize = params->blocksize_bytes;
1995 		} else {
1996 			dev_relthread(dev, ref);
1997 			snprintf(req->error_str, sizeof(req->error_str),
1998 				 "requested blocksize %u is not an even "
1999 				 "multiple of backing device blocksize %u",
2000 				 params->blocksize_bytes, tmp);
2001 			return (EINVAL);
2002 		}
2003 	} else if (params->blocksize_bytes != 0) {
2004 		dev_relthread(dev, ref);
2005 		snprintf(req->error_str, sizeof(req->error_str),
2006 			 "requested blocksize %u < backing device "
2007 			 "blocksize %u", params->blocksize_bytes, tmp);
2008 		return (EINVAL);
2009 	} else if (cbe_lun->lun_type == T_CDROM)
2010 		cbe_lun->blocksize = MAX(tmp, 2048);
2011 	else
2012 		cbe_lun->blocksize = tmp;
2013 
2014 	error = csw->d_ioctl(dev, DIOCGMEDIASIZE, (caddr_t)&otmp, FREAD,
2015 			     curthread);
2016 	if (error) {
2017 		dev_relthread(dev, ref);
2018 		snprintf(req->error_str, sizeof(req->error_str),
2019 			 "error %d returned for DIOCGMEDIASIZE "
2020 			 " ioctl on %s!", error,
2021 			 be_lun->dev_path);
2022 		return (error);
2023 	}
2024 
2025 	if (params->lun_size_bytes != 0) {
2026 		if (params->lun_size_bytes > otmp) {
2027 			dev_relthread(dev, ref);
2028 			snprintf(req->error_str, sizeof(req->error_str),
2029 				 "requested LUN size %ju > backing device "
2030 				 "size %ju",
2031 				 (uintmax_t)params->lun_size_bytes,
2032 				 (uintmax_t)otmp);
2033 			return (EINVAL);
2034 		}
2035 
2036 		be_lun->size_bytes = params->lun_size_bytes;
2037 	} else
2038 		be_lun->size_bytes = otmp;
2039 	be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
2040 	cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
2041 	    0 : (be_lun->size_blocks - 1);
2042 
2043 	error = csw->d_ioctl(dev, DIOCGSTRIPESIZE, (caddr_t)&ps, FREAD,
2044 	    curthread);
2045 	if (error)
2046 		ps = po = 0;
2047 	else {
2048 		error = csw->d_ioctl(dev, DIOCGSTRIPEOFFSET, (caddr_t)&po,
2049 		    FREAD, curthread);
2050 		if (error)
2051 			po = 0;
2052 	}
2053 	us = ps;
2054 	uo = po;
2055 
2056 	value = dnvlist_get_string(cbe_lun->options, "pblocksize", NULL);
2057 	if (value != NULL)
2058 		ctl_expand_number(value, &ps);
2059 	value = dnvlist_get_string(cbe_lun->options, "pblockoffset", NULL);
2060 	if (value != NULL)
2061 		ctl_expand_number(value, &po);
2062 	pss = ps / cbe_lun->blocksize;
2063 	pos = po / cbe_lun->blocksize;
2064 	if ((pss > 0) && (pss * cbe_lun->blocksize == ps) && (pss >= pos) &&
2065 	    ((pss & (pss - 1)) == 0) && (pos * cbe_lun->blocksize == po)) {
2066 		cbe_lun->pblockexp = fls(pss) - 1;
2067 		cbe_lun->pblockoff = (pss - pos) % pss;
2068 	}
2069 
2070 	value = dnvlist_get_string(cbe_lun->options, "ublocksize", NULL);
2071 	if (value != NULL)
2072 		ctl_expand_number(value, &us);
2073 	value = dnvlist_get_string(cbe_lun->options, "ublockoffset", NULL);
2074 	if (value != NULL)
2075 		ctl_expand_number(value, &uo);
2076 	uss = us / cbe_lun->blocksize;
2077 	uos = uo / cbe_lun->blocksize;
2078 	if ((uss > 0) && (uss * cbe_lun->blocksize == us) && (uss >= uos) &&
2079 	    ((uss & (uss - 1)) == 0) && (uos * cbe_lun->blocksize == uo)) {
2080 		cbe_lun->ublockexp = fls(uss) - 1;
2081 		cbe_lun->ublockoff = (uss - uos) % uss;
2082 	}
2083 
2084 	cbe_lun->atomicblock = atomic / cbe_lun->blocksize;
2085 	cbe_lun->opttxferlen = maxio / cbe_lun->blocksize;
2086 
2087 	if (be_lun->dispatch == ctl_be_block_dispatch_zvol) {
2088 		unmap = 1;
2089 	} else {
2090 		struct diocgattr_arg	arg;
2091 
2092 		strlcpy(arg.name, "GEOM::candelete", sizeof(arg.name));
2093 		arg.len = sizeof(arg.value.i);
2094 		error = csw->d_ioctl(dev, DIOCGATTR, (caddr_t)&arg, FREAD,
2095 		    curthread);
2096 		unmap = (error == 0) ? arg.value.i : 0;
2097 	}
2098 	value = dnvlist_get_string(cbe_lun->options, "unmap", NULL);
2099 	if (value != NULL)
2100 		unmap = (strcmp(value, "on") == 0);
2101 	if (unmap)
2102 		cbe_lun->flags |= CTL_LUN_FLAG_UNMAP;
2103 	else
2104 		cbe_lun->flags &= ~CTL_LUN_FLAG_UNMAP;
2105 
2106 	dev_relthread(dev, ref);
2107 	return (0);
2108 }
2109 
2110 static int
2111 ctl_be_block_close(struct ctl_be_block_lun *be_lun)
2112 {
2113 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
2114 	int flags;
2115 
2116 	if (be_lun->vn) {
2117 		flags = FREAD;
2118 		if ((cbe_lun->flags & CTL_LUN_FLAG_READONLY) == 0)
2119 			flags |= FWRITE;
2120 		(void)vn_close(be_lun->vn, flags, NOCRED, curthread);
2121 		be_lun->vn = NULL;
2122 
2123 		switch (be_lun->dev_type) {
2124 		case CTL_BE_BLOCK_DEV:
2125 			break;
2126 		case CTL_BE_BLOCK_FILE:
2127 			if (be_lun->backend.file.cred != NULL) {
2128 				crfree(be_lun->backend.file.cred);
2129 				be_lun->backend.file.cred = NULL;
2130 			}
2131 			break;
2132 		case CTL_BE_BLOCK_NONE:
2133 			break;
2134 		default:
2135 			panic("Unexpected backend type %d", be_lun->dev_type);
2136 			break;
2137 		}
2138 		be_lun->dev_type = CTL_BE_BLOCK_NONE;
2139 	}
2140 	return (0);
2141 }
2142 
2143 static int
2144 ctl_be_block_open(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
2145 {
2146 	struct ctl_be_lun *cbe_lun = &be_lun->cbe_lun;
2147 	struct nameidata nd;
2148 	const char	*value;
2149 	int		 error, flags;
2150 
2151 	error = 0;
2152 	if (rootvnode == NULL) {
2153 		snprintf(req->error_str, sizeof(req->error_str),
2154 			 "Root filesystem is not mounted");
2155 		return (1);
2156 	}
2157 	pwd_ensure_dirs();
2158 
2159 	value = dnvlist_get_string(cbe_lun->options, "file", NULL);
2160 	if (value == NULL) {
2161 		snprintf(req->error_str, sizeof(req->error_str),
2162 			 "no file argument specified");
2163 		return (1);
2164 	}
2165 	free(be_lun->dev_path, M_CTLBLK);
2166 	be_lun->dev_path = strdup(value, M_CTLBLK);
2167 
2168 	flags = FREAD;
2169 	value = dnvlist_get_string(cbe_lun->options, "readonly", NULL);
2170 	if (value != NULL) {
2171 		if (strcmp(value, "on") != 0)
2172 			flags |= FWRITE;
2173 	} else if (cbe_lun->lun_type == T_DIRECT)
2174 		flags |= FWRITE;
2175 
2176 again:
2177 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, be_lun->dev_path, curthread);
2178 	error = vn_open(&nd, &flags, 0, NULL);
2179 	if ((error == EROFS || error == EACCES) && (flags & FWRITE)) {
2180 		flags &= ~FWRITE;
2181 		goto again;
2182 	}
2183 	if (error) {
2184 		/*
2185 		 * This is the only reasonable guess we can make as far as
2186 		 * path if the user doesn't give us a fully qualified path.
2187 		 * If they want to specify a file, they need to specify the
2188 		 * full path.
2189 		 */
2190 		if (be_lun->dev_path[0] != '/') {
2191 			char *dev_name;
2192 
2193 			asprintf(&dev_name, M_CTLBLK, "/dev/%s",
2194 				be_lun->dev_path);
2195 			free(be_lun->dev_path, M_CTLBLK);
2196 			be_lun->dev_path = dev_name;
2197 			goto again;
2198 		}
2199 		snprintf(req->error_str, sizeof(req->error_str),
2200 		    "error opening %s: %d", be_lun->dev_path, error);
2201 		return (error);
2202 	}
2203 	if (flags & FWRITE)
2204 		cbe_lun->flags &= ~CTL_LUN_FLAG_READONLY;
2205 	else
2206 		cbe_lun->flags |= CTL_LUN_FLAG_READONLY;
2207 
2208 	NDFREE(&nd, NDF_ONLY_PNBUF);
2209 	be_lun->vn = nd.ni_vp;
2210 
2211 	/* We only support disks and files. */
2212 	if (vn_isdisk_error(be_lun->vn, &error)) {
2213 		error = ctl_be_block_open_dev(be_lun, req);
2214 	} else if (be_lun->vn->v_type == VREG) {
2215 		error = ctl_be_block_open_file(be_lun, req);
2216 	} else {
2217 		error = EINVAL;
2218 		snprintf(req->error_str, sizeof(req->error_str),
2219 			 "%s is not a disk or plain file", be_lun->dev_path);
2220 	}
2221 	VOP_UNLOCK(be_lun->vn);
2222 
2223 	if (error != 0)
2224 		ctl_be_block_close(be_lun);
2225 	cbe_lun->serseq = CTL_LUN_SERSEQ_OFF;
2226 	if (be_lun->dispatch != ctl_be_block_dispatch_dev)
2227 		cbe_lun->serseq = CTL_LUN_SERSEQ_READ;
2228 	value = dnvlist_get_string(cbe_lun->options, "serseq", NULL);
2229 	if (value != NULL && strcmp(value, "on") == 0)
2230 		cbe_lun->serseq = CTL_LUN_SERSEQ_ON;
2231 	else if (value != NULL && strcmp(value, "read") == 0)
2232 		cbe_lun->serseq = CTL_LUN_SERSEQ_READ;
2233 	else if (value != NULL && strcmp(value, "off") == 0)
2234 		cbe_lun->serseq = CTL_LUN_SERSEQ_OFF;
2235 	return (0);
2236 }
2237 
2238 static int
2239 ctl_be_block_create(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2240 {
2241 	struct ctl_be_lun *cbe_lun;
2242 	struct ctl_be_block_lun *be_lun;
2243 	struct ctl_lun_create_params *params;
2244 	char num_thread_str[16];
2245 	char tmpstr[32];
2246 	const char *value;
2247 	int retval, num_threads;
2248 	int tmp_num_threads;
2249 
2250 	params = &req->reqdata.create;
2251 	retval = 0;
2252 	req->status = CTL_LUN_OK;
2253 
2254 	be_lun = malloc(sizeof(*be_lun), M_CTLBLK, M_ZERO | M_WAITOK);
2255 	cbe_lun = &be_lun->cbe_lun;
2256 	be_lun->params = req->reqdata.create;
2257 	be_lun->softc = softc;
2258 	STAILQ_INIT(&be_lun->input_queue);
2259 	STAILQ_INIT(&be_lun->config_read_queue);
2260 	STAILQ_INIT(&be_lun->config_write_queue);
2261 	STAILQ_INIT(&be_lun->datamove_queue);
2262 	mtx_init(&be_lun->io_lock, "ctlblock io", NULL, MTX_DEF);
2263 	mtx_init(&be_lun->queue_lock, "ctlblock queue", NULL, MTX_DEF);
2264 	cbe_lun->options = nvlist_clone(req->args_nvl);
2265 
2266 	if (params->flags & CTL_LUN_FLAG_DEV_TYPE)
2267 		cbe_lun->lun_type = params->device_type;
2268 	else
2269 		cbe_lun->lun_type = T_DIRECT;
2270 	be_lun->flags = 0;
2271 	cbe_lun->flags = 0;
2272 	value = dnvlist_get_string(cbe_lun->options, "ha_role", NULL);
2273 	if (value != NULL) {
2274 		if (strcmp(value, "primary") == 0)
2275 			cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2276 	} else if (control_softc->flags & CTL_FLAG_ACTIVE_SHELF)
2277 		cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2278 
2279 	if (cbe_lun->lun_type == T_DIRECT ||
2280 	    cbe_lun->lun_type == T_CDROM) {
2281 		be_lun->size_bytes = params->lun_size_bytes;
2282 		if (params->blocksize_bytes != 0)
2283 			cbe_lun->blocksize = params->blocksize_bytes;
2284 		else if (cbe_lun->lun_type == T_CDROM)
2285 			cbe_lun->blocksize = 2048;
2286 		else
2287 			cbe_lun->blocksize = 512;
2288 		be_lun->size_blocks = be_lun->size_bytes / cbe_lun->blocksize;
2289 		cbe_lun->maxlba = (be_lun->size_blocks == 0) ?
2290 		    0 : (be_lun->size_blocks - 1);
2291 
2292 		if ((cbe_lun->flags & CTL_LUN_FLAG_PRIMARY) ||
2293 		    control_softc->ha_mode == CTL_HA_MODE_SER_ONLY) {
2294 			retval = ctl_be_block_open(be_lun, req);
2295 			if (retval != 0) {
2296 				retval = 0;
2297 				req->status = CTL_LUN_WARNING;
2298 			}
2299 		}
2300 		num_threads = cbb_num_threads;
2301 	} else {
2302 		num_threads = 1;
2303 	}
2304 
2305 	value = dnvlist_get_string(cbe_lun->options, "num_threads", NULL);
2306 	if (value != NULL) {
2307 		tmp_num_threads = strtol(value, NULL, 0);
2308 
2309 		/*
2310 		 * We don't let the user specify less than one
2311 		 * thread, but hope he's clueful enough not to
2312 		 * specify 1000 threads.
2313 		 */
2314 		if (tmp_num_threads < 1) {
2315 			snprintf(req->error_str, sizeof(req->error_str),
2316 				 "invalid number of threads %s",
2317 				 num_thread_str);
2318 			goto bailout_error;
2319 		}
2320 		num_threads = tmp_num_threads;
2321 	}
2322 
2323 	if (be_lun->vn == NULL)
2324 		cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2325 	/* Tell the user the blocksize we ended up using */
2326 	params->lun_size_bytes = be_lun->size_bytes;
2327 	params->blocksize_bytes = cbe_lun->blocksize;
2328 	if (params->flags & CTL_LUN_FLAG_ID_REQ) {
2329 		cbe_lun->req_lun_id = params->req_lun_id;
2330 		cbe_lun->flags |= CTL_LUN_FLAG_ID_REQ;
2331 	} else
2332 		cbe_lun->req_lun_id = 0;
2333 
2334 	cbe_lun->lun_shutdown = ctl_be_block_lun_shutdown;
2335 	cbe_lun->be = &ctl_be_block_driver;
2336 
2337 	if ((params->flags & CTL_LUN_FLAG_SERIAL_NUM) == 0) {
2338 		snprintf(tmpstr, sizeof(tmpstr), "MYSERIAL%04d",
2339 			 softc->num_luns);
2340 		strncpy((char *)cbe_lun->serial_num, tmpstr,
2341 			MIN(sizeof(cbe_lun->serial_num), sizeof(tmpstr)));
2342 
2343 		/* Tell the user what we used for a serial number */
2344 		strncpy((char *)params->serial_num, tmpstr,
2345 			MIN(sizeof(params->serial_num), sizeof(tmpstr)));
2346 	} else {
2347 		strncpy((char *)cbe_lun->serial_num, params->serial_num,
2348 			MIN(sizeof(cbe_lun->serial_num),
2349 			sizeof(params->serial_num)));
2350 	}
2351 	if ((params->flags & CTL_LUN_FLAG_DEVID) == 0) {
2352 		snprintf(tmpstr, sizeof(tmpstr), "MYDEVID%04d", softc->num_luns);
2353 		strncpy((char *)cbe_lun->device_id, tmpstr,
2354 			MIN(sizeof(cbe_lun->device_id), sizeof(tmpstr)));
2355 
2356 		/* Tell the user what we used for a device ID */
2357 		strncpy((char *)params->device_id, tmpstr,
2358 			MIN(sizeof(params->device_id), sizeof(tmpstr)));
2359 	} else {
2360 		strncpy((char *)cbe_lun->device_id, params->device_id,
2361 			MIN(sizeof(cbe_lun->device_id),
2362 			    sizeof(params->device_id)));
2363 	}
2364 
2365 	TASK_INIT(&be_lun->io_task, /*priority*/0, ctl_be_block_worker, be_lun);
2366 
2367 	be_lun->io_taskqueue = taskqueue_create("ctlblocktq", M_WAITOK,
2368 	    taskqueue_thread_enqueue, /*context*/&be_lun->io_taskqueue);
2369 
2370 	if (be_lun->io_taskqueue == NULL) {
2371 		snprintf(req->error_str, sizeof(req->error_str),
2372 			 "unable to create taskqueue");
2373 		goto bailout_error;
2374 	}
2375 
2376 	/*
2377 	 * Note that we start the same number of threads by default for
2378 	 * both the file case and the block device case.  For the file
2379 	 * case, we need multiple threads to allow concurrency, because the
2380 	 * vnode interface is designed to be a blocking interface.  For the
2381 	 * block device case, ZFS zvols at least will block the caller's
2382 	 * context in many instances, and so we need multiple threads to
2383 	 * overcome that problem.  Other block devices don't need as many
2384 	 * threads, but they shouldn't cause too many problems.
2385 	 *
2386 	 * If the user wants to just have a single thread for a block
2387 	 * device, he can specify that when the LUN is created, or change
2388 	 * the tunable/sysctl to alter the default number of threads.
2389 	 */
2390 	retval = taskqueue_start_threads_in_proc(&be_lun->io_taskqueue,
2391 					 /*num threads*/num_threads,
2392 					 /*priority*/PUSER,
2393 					 /*proc*/control_softc->ctl_proc,
2394 					 /*thread name*/"block");
2395 
2396 	if (retval != 0)
2397 		goto bailout_error;
2398 
2399 	be_lun->num_threads = num_threads;
2400 
2401 	retval = ctl_add_lun(&be_lun->cbe_lun);
2402 	if (retval != 0) {
2403 		snprintf(req->error_str, sizeof(req->error_str),
2404 			 "ctl_add_lun() returned error %d, see dmesg for "
2405 			 "details", retval);
2406 		retval = 0;
2407 		goto bailout_error;
2408 	}
2409 
2410 	be_lun->disk_stats = devstat_new_entry("cbb", cbe_lun->lun_id,
2411 					       cbe_lun->blocksize,
2412 					       DEVSTAT_ALL_SUPPORTED,
2413 					       cbe_lun->lun_type
2414 					       | DEVSTAT_TYPE_IF_OTHER,
2415 					       DEVSTAT_PRIORITY_OTHER);
2416 
2417 	mtx_lock(&softc->lock);
2418 	softc->num_luns++;
2419 	SLIST_INSERT_HEAD(&softc->lun_list, be_lun, links);
2420 	mtx_unlock(&softc->lock);
2421 
2422 	params->req_lun_id = cbe_lun->lun_id;
2423 
2424 	return (retval);
2425 
2426 bailout_error:
2427 	req->status = CTL_LUN_ERROR;
2428 
2429 	if (be_lun->io_taskqueue != NULL)
2430 		taskqueue_free(be_lun->io_taskqueue);
2431 	ctl_be_block_close(be_lun);
2432 	if (be_lun->dev_path != NULL)
2433 		free(be_lun->dev_path, M_CTLBLK);
2434 	nvlist_destroy(cbe_lun->options);
2435 	mtx_destroy(&be_lun->queue_lock);
2436 	mtx_destroy(&be_lun->io_lock);
2437 	free(be_lun, M_CTLBLK);
2438 
2439 	return (retval);
2440 }
2441 
2442 static int
2443 ctl_be_block_rm(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2444 {
2445 	struct ctl_lun_rm_params *params;
2446 	struct ctl_be_block_lun *be_lun;
2447 	struct ctl_be_lun *cbe_lun;
2448 	int retval;
2449 
2450 	params = &req->reqdata.rm;
2451 
2452 	sx_xlock(&softc->modify_lock);
2453 	mtx_lock(&softc->lock);
2454 	SLIST_FOREACH(be_lun, &softc->lun_list, links) {
2455 		if (be_lun->cbe_lun.lun_id == params->lun_id) {
2456 			SLIST_REMOVE(&softc->lun_list, be_lun,
2457 			    ctl_be_block_lun, links);
2458 			softc->num_luns--;
2459 			break;
2460 		}
2461 	}
2462 	mtx_unlock(&softc->lock);
2463 	sx_xunlock(&softc->modify_lock);
2464 	if (be_lun == NULL) {
2465 		snprintf(req->error_str, sizeof(req->error_str),
2466 			 "LUN %u is not managed by the block backend",
2467 			 params->lun_id);
2468 		goto bailout_error;
2469 	}
2470 	cbe_lun = &be_lun->cbe_lun;
2471 
2472 	if (be_lun->vn != NULL) {
2473 		cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2474 		ctl_lun_no_media(cbe_lun);
2475 		taskqueue_drain_all(be_lun->io_taskqueue);
2476 		ctl_be_block_close(be_lun);
2477 	}
2478 
2479 	mtx_lock(&softc->lock);
2480 	be_lun->flags |= CTL_BE_BLOCK_LUN_WAITING;
2481 	mtx_unlock(&softc->lock);
2482 
2483 	retval = ctl_remove_lun(cbe_lun);
2484 	if (retval != 0) {
2485 		snprintf(req->error_str, sizeof(req->error_str),
2486 			 "error %d returned from ctl_remove_lun() for "
2487 			 "LUN %d", retval, params->lun_id);
2488 		mtx_lock(&softc->lock);
2489 		be_lun->flags &= ~CTL_BE_BLOCK_LUN_WAITING;
2490 		mtx_unlock(&softc->lock);
2491 		goto bailout_error;
2492 	}
2493 
2494 	mtx_lock(&softc->lock);
2495 	while ((be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) == 0) {
2496 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlblockrm", 0);
2497 		if (retval == EINTR)
2498 			break;
2499 	}
2500 	be_lun->flags &= ~CTL_BE_BLOCK_LUN_WAITING;
2501 	if (be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) {
2502 		mtx_unlock(&softc->lock);
2503 		free(be_lun, M_CTLBLK);
2504 	} else {
2505 		mtx_unlock(&softc->lock);
2506 		return (EINTR);
2507 	}
2508 
2509 	req->status = CTL_LUN_OK;
2510 	return (0);
2511 
2512 bailout_error:
2513 	req->status = CTL_LUN_ERROR;
2514 	return (0);
2515 }
2516 
2517 static int
2518 ctl_be_block_modify(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2519 {
2520 	struct ctl_lun_modify_params *params;
2521 	struct ctl_be_block_lun *be_lun;
2522 	struct ctl_be_lun *cbe_lun;
2523 	const char *value;
2524 	uint64_t oldsize;
2525 	int error, wasprim;
2526 
2527 	params = &req->reqdata.modify;
2528 
2529 	sx_xlock(&softc->modify_lock);
2530 	mtx_lock(&softc->lock);
2531 	SLIST_FOREACH(be_lun, &softc->lun_list, links) {
2532 		if (be_lun->cbe_lun.lun_id == params->lun_id)
2533 			break;
2534 	}
2535 	mtx_unlock(&softc->lock);
2536 	if (be_lun == NULL) {
2537 		snprintf(req->error_str, sizeof(req->error_str),
2538 			 "LUN %u is not managed by the block backend",
2539 			 params->lun_id);
2540 		goto bailout_error;
2541 	}
2542 	cbe_lun = &be_lun->cbe_lun;
2543 
2544 	if (params->lun_size_bytes != 0)
2545 		be_lun->params.lun_size_bytes = params->lun_size_bytes;
2546 
2547 	if (req->args_nvl != NULL) {
2548 		nvlist_destroy(cbe_lun->options);
2549 		cbe_lun->options = nvlist_clone(req->args_nvl);
2550 	}
2551 
2552 	wasprim = (cbe_lun->flags & CTL_LUN_FLAG_PRIMARY);
2553 	value = dnvlist_get_string(cbe_lun->options, "ha_role", NULL);
2554 	if (value != NULL) {
2555 		if (strcmp(value, "primary") == 0)
2556 			cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2557 		else
2558 			cbe_lun->flags &= ~CTL_LUN_FLAG_PRIMARY;
2559 	} else if (control_softc->flags & CTL_FLAG_ACTIVE_SHELF)
2560 		cbe_lun->flags |= CTL_LUN_FLAG_PRIMARY;
2561 	else
2562 		cbe_lun->flags &= ~CTL_LUN_FLAG_PRIMARY;
2563 	if (wasprim != (cbe_lun->flags & CTL_LUN_FLAG_PRIMARY)) {
2564 		if (cbe_lun->flags & CTL_LUN_FLAG_PRIMARY)
2565 			ctl_lun_primary(cbe_lun);
2566 		else
2567 			ctl_lun_secondary(cbe_lun);
2568 	}
2569 
2570 	oldsize = be_lun->size_blocks;
2571 	if ((cbe_lun->flags & CTL_LUN_FLAG_PRIMARY) ||
2572 	    control_softc->ha_mode == CTL_HA_MODE_SER_ONLY) {
2573 		if (be_lun->vn == NULL)
2574 			error = ctl_be_block_open(be_lun, req);
2575 		else if (vn_isdisk_error(be_lun->vn, &error))
2576 			error = ctl_be_block_open_dev(be_lun, req);
2577 		else if (be_lun->vn->v_type == VREG) {
2578 			vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
2579 			error = ctl_be_block_open_file(be_lun, req);
2580 			VOP_UNLOCK(be_lun->vn);
2581 		} else
2582 			error = EINVAL;
2583 		if ((cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) &&
2584 		    be_lun->vn != NULL) {
2585 			cbe_lun->flags &= ~CTL_LUN_FLAG_NO_MEDIA;
2586 			ctl_lun_has_media(cbe_lun);
2587 		} else if ((cbe_lun->flags & CTL_LUN_FLAG_NO_MEDIA) == 0 &&
2588 		    be_lun->vn == NULL) {
2589 			cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2590 			ctl_lun_no_media(cbe_lun);
2591 		}
2592 		cbe_lun->flags &= ~CTL_LUN_FLAG_EJECTED;
2593 	} else {
2594 		if (be_lun->vn != NULL) {
2595 			cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2596 			ctl_lun_no_media(cbe_lun);
2597 			taskqueue_drain_all(be_lun->io_taskqueue);
2598 			error = ctl_be_block_close(be_lun);
2599 		} else
2600 			error = 0;
2601 	}
2602 	if (be_lun->size_blocks != oldsize)
2603 		ctl_lun_capacity_changed(cbe_lun);
2604 
2605 	/* Tell the user the exact size we ended up using */
2606 	params->lun_size_bytes = be_lun->size_bytes;
2607 
2608 	sx_xunlock(&softc->modify_lock);
2609 	req->status = error ? CTL_LUN_WARNING : CTL_LUN_OK;
2610 	return (0);
2611 
2612 bailout_error:
2613 	sx_xunlock(&softc->modify_lock);
2614 	req->status = CTL_LUN_ERROR;
2615 	return (0);
2616 }
2617 
2618 static void
2619 ctl_be_block_lun_shutdown(struct ctl_be_lun *cbe_lun)
2620 {
2621 	struct ctl_be_block_lun *be_lun = (struct ctl_be_block_lun *)cbe_lun;
2622 	struct ctl_be_block_softc *softc = be_lun->softc;
2623 
2624 	taskqueue_drain_all(be_lun->io_taskqueue);
2625 	taskqueue_free(be_lun->io_taskqueue);
2626 	if (be_lun->disk_stats != NULL)
2627 		devstat_remove_entry(be_lun->disk_stats);
2628 	nvlist_destroy(be_lun->cbe_lun.options);
2629 	free(be_lun->dev_path, M_CTLBLK);
2630 	mtx_destroy(&be_lun->queue_lock);
2631 	mtx_destroy(&be_lun->io_lock);
2632 
2633 	mtx_lock(&softc->lock);
2634 	be_lun->flags |= CTL_BE_BLOCK_LUN_UNCONFIGURED;
2635 	if (be_lun->flags & CTL_BE_BLOCK_LUN_WAITING)
2636 		wakeup(be_lun);
2637 	else
2638 		free(be_lun, M_CTLBLK);
2639 	mtx_unlock(&softc->lock);
2640 }
2641 
2642 static int
2643 ctl_be_block_config_write(union ctl_io *io)
2644 {
2645 	struct ctl_be_block_lun *be_lun;
2646 	struct ctl_be_lun *cbe_lun;
2647 	int retval;
2648 
2649 	DPRINTF("entered\n");
2650 
2651 	cbe_lun = CTL_BACKEND_LUN(io);
2652 	be_lun = (struct ctl_be_block_lun *)cbe_lun;
2653 
2654 	retval = 0;
2655 	switch (io->scsiio.cdb[0]) {
2656 	case SYNCHRONIZE_CACHE:
2657 	case SYNCHRONIZE_CACHE_16:
2658 	case WRITE_SAME_10:
2659 	case WRITE_SAME_16:
2660 	case UNMAP:
2661 		/*
2662 		 * The upper level CTL code will filter out any CDBs with
2663 		 * the immediate bit set and return the proper error.
2664 		 *
2665 		 * We don't really need to worry about what LBA range the
2666 		 * user asked to be synced out.  When they issue a sync
2667 		 * cache command, we'll sync out the whole thing.
2668 		 */
2669 		mtx_lock(&be_lun->queue_lock);
2670 		STAILQ_INSERT_TAIL(&be_lun->config_write_queue, &io->io_hdr,
2671 				   links);
2672 		mtx_unlock(&be_lun->queue_lock);
2673 		taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
2674 		break;
2675 	case START_STOP_UNIT: {
2676 		struct scsi_start_stop_unit *cdb;
2677 		struct ctl_lun_req req;
2678 
2679 		cdb = (struct scsi_start_stop_unit *)io->scsiio.cdb;
2680 		if ((cdb->how & SSS_PC_MASK) != 0) {
2681 			ctl_set_success(&io->scsiio);
2682 			ctl_config_write_done(io);
2683 			break;
2684 		}
2685 		if (cdb->how & SSS_START) {
2686 			if ((cdb->how & SSS_LOEJ) && be_lun->vn == NULL) {
2687 				retval = ctl_be_block_open(be_lun, &req);
2688 				cbe_lun->flags &= ~CTL_LUN_FLAG_EJECTED;
2689 				if (retval == 0) {
2690 					cbe_lun->flags &= ~CTL_LUN_FLAG_NO_MEDIA;
2691 					ctl_lun_has_media(cbe_lun);
2692 				} else {
2693 					cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2694 					ctl_lun_no_media(cbe_lun);
2695 				}
2696 			}
2697 			ctl_start_lun(cbe_lun);
2698 		} else {
2699 			ctl_stop_lun(cbe_lun);
2700 			if (cdb->how & SSS_LOEJ) {
2701 				cbe_lun->flags |= CTL_LUN_FLAG_NO_MEDIA;
2702 				cbe_lun->flags |= CTL_LUN_FLAG_EJECTED;
2703 				ctl_lun_ejected(cbe_lun);
2704 				if (be_lun->vn != NULL)
2705 					ctl_be_block_close(be_lun);
2706 			}
2707 		}
2708 
2709 		ctl_set_success(&io->scsiio);
2710 		ctl_config_write_done(io);
2711 		break;
2712 	}
2713 	case PREVENT_ALLOW:
2714 		ctl_set_success(&io->scsiio);
2715 		ctl_config_write_done(io);
2716 		break;
2717 	default:
2718 		ctl_set_invalid_opcode(&io->scsiio);
2719 		ctl_config_write_done(io);
2720 		retval = CTL_RETVAL_COMPLETE;
2721 		break;
2722 	}
2723 
2724 	return (retval);
2725 }
2726 
2727 static int
2728 ctl_be_block_config_read(union ctl_io *io)
2729 {
2730 	struct ctl_be_block_lun *be_lun;
2731 	int retval = 0;
2732 
2733 	DPRINTF("entered\n");
2734 
2735 	be_lun = (struct ctl_be_block_lun *)CTL_BACKEND_LUN(io);
2736 
2737 	switch (io->scsiio.cdb[0]) {
2738 	case SERVICE_ACTION_IN:
2739 		if (io->scsiio.cdb[1] == SGLS_SERVICE_ACTION) {
2740 			mtx_lock(&be_lun->queue_lock);
2741 			STAILQ_INSERT_TAIL(&be_lun->config_read_queue,
2742 			    &io->io_hdr, links);
2743 			mtx_unlock(&be_lun->queue_lock);
2744 			taskqueue_enqueue(be_lun->io_taskqueue,
2745 			    &be_lun->io_task);
2746 			retval = CTL_RETVAL_QUEUED;
2747 			break;
2748 		}
2749 		ctl_set_invalid_field(&io->scsiio,
2750 				      /*sks_valid*/ 1,
2751 				      /*command*/ 1,
2752 				      /*field*/ 1,
2753 				      /*bit_valid*/ 1,
2754 				      /*bit*/ 4);
2755 		ctl_config_read_done(io);
2756 		retval = CTL_RETVAL_COMPLETE;
2757 		break;
2758 	default:
2759 		ctl_set_invalid_opcode(&io->scsiio);
2760 		ctl_config_read_done(io);
2761 		retval = CTL_RETVAL_COMPLETE;
2762 		break;
2763 	}
2764 
2765 	return (retval);
2766 }
2767 
2768 static int
2769 ctl_be_block_lun_info(struct ctl_be_lun *cbe_lun, struct sbuf *sb)
2770 {
2771 	struct ctl_be_block_lun *lun = (struct ctl_be_block_lun *)cbe_lun;
2772 	int retval;
2773 
2774 	retval = sbuf_printf(sb, "\t<num_threads>");
2775 	if (retval != 0)
2776 		goto bailout;
2777 	retval = sbuf_printf(sb, "%d", lun->num_threads);
2778 	if (retval != 0)
2779 		goto bailout;
2780 	retval = sbuf_printf(sb, "</num_threads>\n");
2781 
2782 bailout:
2783 	return (retval);
2784 }
2785 
2786 static uint64_t
2787 ctl_be_block_lun_attr(struct ctl_be_lun *cbe_lun, const char *attrname)
2788 {
2789 	struct ctl_be_block_lun *lun = (struct ctl_be_block_lun *)cbe_lun;
2790 
2791 	if (lun->getattr == NULL)
2792 		return (UINT64_MAX);
2793 	return (lun->getattr(lun, attrname));
2794 }
2795 
2796 static int
2797 ctl_be_block_init(void)
2798 {
2799 	struct ctl_be_block_softc *softc = &backend_block_softc;
2800 
2801 	sx_init(&softc->modify_lock, "ctlblock modify");
2802 	mtx_init(&softc->lock, "ctlblock", NULL, MTX_DEF);
2803 	softc->beio_zone = uma_zcreate("beio", sizeof(struct ctl_be_block_io),
2804 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
2805 	softc->buf_zone = uma_zcreate("ctlblock", CTLBLK_MAX_SEG,
2806 	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
2807 #if (CTLBLK_MAX_SEG > 131072)
2808 	softc->buf128_zone = uma_zcreate("ctlblock128", 131072,
2809 	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
2810 #endif
2811 	SLIST_INIT(&softc->lun_list);
2812 	return (0);
2813 }
2814 
2815 static int
2816 ctl_be_block_shutdown(void)
2817 {
2818 	struct ctl_be_block_softc *softc = &backend_block_softc;
2819 	struct ctl_be_block_lun *lun;
2820 
2821 	mtx_lock(&softc->lock);
2822 	while ((lun = SLIST_FIRST(&softc->lun_list)) != NULL) {
2823 		SLIST_REMOVE_HEAD(&softc->lun_list, links);
2824 		softc->num_luns--;
2825 		/*
2826 		 * Drop our lock here.  Since ctl_remove_lun() can call
2827 		 * back into us, this could potentially lead to a recursive
2828 		 * lock of the same mutex, which would cause a hang.
2829 		 */
2830 		mtx_unlock(&softc->lock);
2831 		ctl_remove_lun(&lun->cbe_lun);
2832 		mtx_lock(&softc->lock);
2833 	}
2834 	mtx_unlock(&softc->lock);
2835 	uma_zdestroy(softc->buf_zone);
2836 #if (CTLBLK_MAX_SEG > 131072)
2837 	uma_zdestroy(softc->buf128_zone);
2838 #endif
2839 	uma_zdestroy(softc->beio_zone);
2840 	mtx_destroy(&softc->lock);
2841 	sx_destroy(&softc->modify_lock);
2842 	return (0);
2843 }
2844