xref: /freebsd/sys/cam/ctl/ctl_backend_block.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
1 /*-
2  * Copyright (c) 2003 Silicon Graphics International Corp.
3  * Copyright (c) 2009-2011 Spectra Logic Corporation
4  * Copyright (c) 2012 The FreeBSD Foundation
5  * All rights reserved.
6  *
7  * Portions of this software were developed by Edward Tomasz Napierala
8  * under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions, and the following disclaimer,
15  *    without modification.
16  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
17  *    substantially similar to the "NO WARRANTY" disclaimer below
18  *    ("Disclaimer") and any redistribution must be conditioned upon
19  *    including a substantially similar Disclaimer requirement for further
20  *    binary redistribution.
21  *
22  * NO WARRANTY
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
32  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGES.
34  *
35  * $Id: //depot/users/kenm/FreeBSD-test2/sys/cam/ctl/ctl_backend_block.c#5 $
36  */
37 /*
38  * CAM Target Layer driver backend for block devices.
39  *
40  * Author: Ken Merry <ken@FreeBSD.org>
41  */
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/types.h>
49 #include <sys/kthread.h>
50 #include <sys/bio.h>
51 #include <sys/fcntl.h>
52 #include <sys/limits.h>
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <sys/condvar.h>
56 #include <sys/malloc.h>
57 #include <sys/conf.h>
58 #include <sys/ioccom.h>
59 #include <sys/queue.h>
60 #include <sys/sbuf.h>
61 #include <sys/endian.h>
62 #include <sys/uio.h>
63 #include <sys/buf.h>
64 #include <sys/taskqueue.h>
65 #include <sys/vnode.h>
66 #include <sys/namei.h>
67 #include <sys/mount.h>
68 #include <sys/disk.h>
69 #include <sys/fcntl.h>
70 #include <sys/filedesc.h>
71 #include <sys/filio.h>
72 #include <sys/proc.h>
73 #include <sys/pcpu.h>
74 #include <sys/module.h>
75 #include <sys/sdt.h>
76 #include <sys/devicestat.h>
77 #include <sys/sysctl.h>
78 
79 #include <geom/geom.h>
80 
81 #include <cam/cam.h>
82 #include <cam/scsi/scsi_all.h>
83 #include <cam/scsi/scsi_da.h>
84 #include <cam/ctl/ctl_io.h>
85 #include <cam/ctl/ctl.h>
86 #include <cam/ctl/ctl_backend.h>
87 #include <cam/ctl/ctl_frontend_internal.h>
88 #include <cam/ctl/ctl_ioctl.h>
89 #include <cam/ctl/ctl_scsi_all.h>
90 #include <cam/ctl/ctl_error.h>
91 
92 /*
93  * The idea here is that we'll allocate enough S/G space to hold a 1MB
94  * I/O.  If we get an I/O larger than that, we'll split it.
95  */
96 #define	CTLBLK_HALF_IO_SIZE	(512 * 1024)
97 #define	CTLBLK_MAX_IO_SIZE	(CTLBLK_HALF_IO_SIZE * 2)
98 #define	CTLBLK_MAX_SEG		MAXPHYS
99 #define	CTLBLK_HALF_SEGS	MAX(CTLBLK_HALF_IO_SIZE / CTLBLK_MAX_SEG, 1)
100 #define	CTLBLK_MAX_SEGS		(CTLBLK_HALF_SEGS * 2)
101 
102 #ifdef CTLBLK_DEBUG
103 #define DPRINTF(fmt, args...) \
104     printf("cbb(%s:%d): " fmt, __FUNCTION__, __LINE__, ##args)
105 #else
106 #define DPRINTF(fmt, args...) do {} while(0)
107 #endif
108 
109 #define PRIV(io)	\
110     ((struct ctl_ptr_len_flags *)&(io)->io_hdr.ctl_private[CTL_PRIV_BACKEND])
111 #define ARGS(io)	\
112     ((struct ctl_lba_len_flags *)&(io)->io_hdr.ctl_private[CTL_PRIV_LBA_LEN])
113 
114 SDT_PROVIDER_DEFINE(cbb);
115 
116 typedef enum {
117 	CTL_BE_BLOCK_LUN_UNCONFIGURED	= 0x01,
118 	CTL_BE_BLOCK_LUN_CONFIG_ERR	= 0x02,
119 	CTL_BE_BLOCK_LUN_WAITING	= 0x04,
120 	CTL_BE_BLOCK_LUN_MULTI_THREAD	= 0x08
121 } ctl_be_block_lun_flags;
122 
123 typedef enum {
124 	CTL_BE_BLOCK_NONE,
125 	CTL_BE_BLOCK_DEV,
126 	CTL_BE_BLOCK_FILE
127 } ctl_be_block_type;
128 
129 struct ctl_be_block_devdata {
130 	struct cdev *cdev;
131 	struct cdevsw *csw;
132 	int dev_ref;
133 };
134 
135 struct ctl_be_block_filedata {
136 	struct ucred *cred;
137 };
138 
139 union ctl_be_block_bedata {
140 	struct ctl_be_block_devdata dev;
141 	struct ctl_be_block_filedata file;
142 };
143 
144 struct ctl_be_block_io;
145 struct ctl_be_block_lun;
146 
147 typedef void (*cbb_dispatch_t)(struct ctl_be_block_lun *be_lun,
148 			       struct ctl_be_block_io *beio);
149 typedef uint64_t (*cbb_getattr_t)(struct ctl_be_block_lun *be_lun,
150 				  const char *attrname);
151 
152 /*
153  * Backend LUN structure.  There is a 1:1 mapping between a block device
154  * and a backend block LUN, and between a backend block LUN and a CTL LUN.
155  */
156 struct ctl_be_block_lun {
157 	struct ctl_lun_create_params params;
158 	struct ctl_block_disk *disk;
159 	char lunname[32];
160 	char *dev_path;
161 	ctl_be_block_type dev_type;
162 	struct vnode *vn;
163 	union ctl_be_block_bedata backend;
164 	cbb_dispatch_t dispatch;
165 	cbb_dispatch_t lun_flush;
166 	cbb_dispatch_t unmap;
167 	cbb_dispatch_t get_lba_status;
168 	cbb_getattr_t getattr;
169 	uma_zone_t lun_zone;
170 	uint64_t size_blocks;
171 	uint64_t size_bytes;
172 	uint32_t blocksize;
173 	int blocksize_shift;
174 	uint16_t pblockexp;
175 	uint16_t pblockoff;
176 	uint16_t ublockexp;
177 	uint16_t ublockoff;
178 	uint32_t atomicblock;
179 	uint32_t opttxferlen;
180 	struct ctl_be_block_softc *softc;
181 	struct devstat *disk_stats;
182 	ctl_be_block_lun_flags flags;
183 	STAILQ_ENTRY(ctl_be_block_lun) links;
184 	struct ctl_be_lun ctl_be_lun;
185 	struct taskqueue *io_taskqueue;
186 	struct task io_task;
187 	int num_threads;
188 	STAILQ_HEAD(, ctl_io_hdr) input_queue;
189 	STAILQ_HEAD(, ctl_io_hdr) config_read_queue;
190 	STAILQ_HEAD(, ctl_io_hdr) config_write_queue;
191 	STAILQ_HEAD(, ctl_io_hdr) datamove_queue;
192 	struct mtx_padalign io_lock;
193 	struct mtx_padalign queue_lock;
194 };
195 
196 /*
197  * Overall softc structure for the block backend module.
198  */
199 struct ctl_be_block_softc {
200 	struct mtx			 lock;
201 	int				 num_disks;
202 	STAILQ_HEAD(, ctl_block_disk)	 disk_list;
203 	int				 num_luns;
204 	STAILQ_HEAD(, ctl_be_block_lun)	 lun_list;
205 };
206 
207 static struct ctl_be_block_softc backend_block_softc;
208 
209 /*
210  * Per-I/O information.
211  */
212 struct ctl_be_block_io {
213 	union ctl_io			*io;
214 	struct ctl_sg_entry		sg_segs[CTLBLK_MAX_SEGS];
215 	struct iovec			xiovecs[CTLBLK_MAX_SEGS];
216 	int				bio_cmd;
217 	int				num_segs;
218 	int				num_bios_sent;
219 	int				num_bios_done;
220 	int				send_complete;
221 	int				num_errors;
222 	struct bintime			ds_t0;
223 	devstat_tag_type		ds_tag_type;
224 	devstat_trans_flags		ds_trans_type;
225 	uint64_t			io_len;
226 	uint64_t			io_offset;
227 	struct ctl_be_block_softc	*softc;
228 	struct ctl_be_block_lun		*lun;
229 	void (*beio_cont)(struct ctl_be_block_io *beio); /* to continue processing */
230 };
231 
232 static int cbb_num_threads = 14;
233 SYSCTL_NODE(_kern_cam_ctl, OID_AUTO, block, CTLFLAG_RD, 0,
234 	    "CAM Target Layer Block Backend");
235 SYSCTL_INT(_kern_cam_ctl_block, OID_AUTO, num_threads, CTLFLAG_RWTUN,
236            &cbb_num_threads, 0, "Number of threads per backing file");
237 
238 static struct ctl_be_block_io *ctl_alloc_beio(struct ctl_be_block_softc *softc);
239 static void ctl_free_beio(struct ctl_be_block_io *beio);
240 static void ctl_complete_beio(struct ctl_be_block_io *beio);
241 static int ctl_be_block_move_done(union ctl_io *io);
242 static void ctl_be_block_biodone(struct bio *bio);
243 static void ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
244 				    struct ctl_be_block_io *beio);
245 static void ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
246 				       struct ctl_be_block_io *beio);
247 static void ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
248 				  struct ctl_be_block_io *beio);
249 static uint64_t ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun,
250 					 const char *attrname);
251 static void ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
252 				   struct ctl_be_block_io *beio);
253 static void ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
254 				   struct ctl_be_block_io *beio);
255 static void ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
256 				      struct ctl_be_block_io *beio);
257 static uint64_t ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun,
258 					 const char *attrname);
259 static void ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
260 				    union ctl_io *io);
261 static void ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
262 				    union ctl_io *io);
263 static void ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
264 				  union ctl_io *io);
265 static void ctl_be_block_worker(void *context, int pending);
266 static int ctl_be_block_submit(union ctl_io *io);
267 static int ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
268 				   int flag, struct thread *td);
269 static int ctl_be_block_open_file(struct ctl_be_block_lun *be_lun,
270 				  struct ctl_lun_req *req);
271 static int ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun,
272 				 struct ctl_lun_req *req);
273 static int ctl_be_block_close(struct ctl_be_block_lun *be_lun);
274 static int ctl_be_block_open(struct ctl_be_block_softc *softc,
275 			     struct ctl_be_block_lun *be_lun,
276 			     struct ctl_lun_req *req);
277 static int ctl_be_block_create(struct ctl_be_block_softc *softc,
278 			       struct ctl_lun_req *req);
279 static int ctl_be_block_rm(struct ctl_be_block_softc *softc,
280 			   struct ctl_lun_req *req);
281 static int ctl_be_block_modify_file(struct ctl_be_block_lun *be_lun,
282 				  struct ctl_lun_req *req);
283 static int ctl_be_block_modify_dev(struct ctl_be_block_lun *be_lun,
284 				 struct ctl_lun_req *req);
285 static int ctl_be_block_modify(struct ctl_be_block_softc *softc,
286 			   struct ctl_lun_req *req);
287 static void ctl_be_block_lun_shutdown(void *be_lun);
288 static void ctl_be_block_lun_config_status(void *be_lun,
289 					   ctl_lun_config_status status);
290 static int ctl_be_block_config_write(union ctl_io *io);
291 static int ctl_be_block_config_read(union ctl_io *io);
292 static int ctl_be_block_lun_info(void *be_lun, struct sbuf *sb);
293 static uint64_t ctl_be_block_lun_attr(void *be_lun, const char *attrname);
294 int ctl_be_block_init(void);
295 
296 static struct ctl_backend_driver ctl_be_block_driver =
297 {
298 	.name = "block",
299 	.flags = CTL_BE_FLAG_HAS_CONFIG,
300 	.init = ctl_be_block_init,
301 	.data_submit = ctl_be_block_submit,
302 	.data_move_done = ctl_be_block_move_done,
303 	.config_read = ctl_be_block_config_read,
304 	.config_write = ctl_be_block_config_write,
305 	.ioctl = ctl_be_block_ioctl,
306 	.lun_info = ctl_be_block_lun_info,
307 	.lun_attr = ctl_be_block_lun_attr
308 };
309 
310 MALLOC_DEFINE(M_CTLBLK, "ctlblk", "Memory used for CTL block backend");
311 CTL_BACKEND_DECLARE(cbb, ctl_be_block_driver);
312 
313 static uma_zone_t beio_zone;
314 
315 static struct ctl_be_block_io *
316 ctl_alloc_beio(struct ctl_be_block_softc *softc)
317 {
318 	struct ctl_be_block_io *beio;
319 
320 	beio = uma_zalloc(beio_zone, M_WAITOK | M_ZERO);
321 	beio->softc = softc;
322 	return (beio);
323 }
324 
325 static void
326 ctl_free_beio(struct ctl_be_block_io *beio)
327 {
328 	int duplicate_free;
329 	int i;
330 
331 	duplicate_free = 0;
332 
333 	for (i = 0; i < beio->num_segs; i++) {
334 		if (beio->sg_segs[i].addr == NULL)
335 			duplicate_free++;
336 
337 		uma_zfree(beio->lun->lun_zone, beio->sg_segs[i].addr);
338 		beio->sg_segs[i].addr = NULL;
339 
340 		/* For compare we had two equal S/G lists. */
341 		if (ARGS(beio->io)->flags & CTL_LLF_COMPARE) {
342 			uma_zfree(beio->lun->lun_zone,
343 			    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr);
344 			beio->sg_segs[i + CTLBLK_HALF_SEGS].addr = NULL;
345 		}
346 	}
347 
348 	if (duplicate_free > 0) {
349 		printf("%s: %d duplicate frees out of %d segments\n", __func__,
350 		       duplicate_free, beio->num_segs);
351 	}
352 
353 	uma_zfree(beio_zone, beio);
354 }
355 
356 static void
357 ctl_complete_beio(struct ctl_be_block_io *beio)
358 {
359 	union ctl_io *io = beio->io;
360 
361 	if (beio->beio_cont != NULL) {
362 		beio->beio_cont(beio);
363 	} else {
364 		ctl_free_beio(beio);
365 		ctl_data_submit_done(io);
366 	}
367 }
368 
369 static int
370 ctl_be_block_move_done(union ctl_io *io)
371 {
372 	struct ctl_be_block_io *beio;
373 	struct ctl_be_block_lun *be_lun;
374 	struct ctl_lba_len_flags *lbalen;
375 #ifdef CTL_TIME_IO
376 	struct bintime cur_bt;
377 #endif
378 	int i;
379 
380 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
381 	be_lun = beio->lun;
382 
383 	DPRINTF("entered\n");
384 
385 #ifdef CTL_TIME_IO
386 	getbintime(&cur_bt);
387 	bintime_sub(&cur_bt, &io->io_hdr.dma_start_bt);
388 	bintime_add(&io->io_hdr.dma_bt, &cur_bt);
389 	io->io_hdr.num_dmas++;
390 #endif
391 	io->scsiio.kern_rel_offset += io->scsiio.kern_data_len;
392 
393 	/*
394 	 * We set status at this point for read commands, and write
395 	 * commands with errors.
396 	 */
397 	if (io->io_hdr.flags & CTL_FLAG_ABORT) {
398 		;
399 	} else if ((io->io_hdr.port_status == 0) &&
400 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE)) {
401 		lbalen = ARGS(beio->io);
402 		if (lbalen->flags & CTL_LLF_READ) {
403 			ctl_set_success(&io->scsiio);
404 		} else if (lbalen->flags & CTL_LLF_COMPARE) {
405 			/* We have two data blocks ready for comparison. */
406 			for (i = 0; i < beio->num_segs; i++) {
407 				if (memcmp(beio->sg_segs[i].addr,
408 				    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr,
409 				    beio->sg_segs[i].len) != 0)
410 					break;
411 			}
412 			if (i < beio->num_segs)
413 				ctl_set_sense(&io->scsiio,
414 				    /*current_error*/ 1,
415 				    /*sense_key*/ SSD_KEY_MISCOMPARE,
416 				    /*asc*/ 0x1D,
417 				    /*ascq*/ 0x00,
418 				    SSD_ELEM_NONE);
419 			else
420 				ctl_set_success(&io->scsiio);
421 		}
422 	} else if ((io->io_hdr.port_status != 0) &&
423 	    ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE ||
424 	     (io->io_hdr.status & CTL_STATUS_MASK) == CTL_SUCCESS)) {
425 		/*
426 		 * For hardware error sense keys, the sense key
427 		 * specific value is defined to be a retry count,
428 		 * but we use it to pass back an internal FETD
429 		 * error code.  XXX KDM  Hopefully the FETD is only
430 		 * using 16 bits for an error code, since that's
431 		 * all the space we have in the sks field.
432 		 */
433 		ctl_set_internal_failure(&io->scsiio,
434 					 /*sks_valid*/ 1,
435 					 /*retry_count*/
436 					 io->io_hdr.port_status);
437 	}
438 
439 	/*
440 	 * If this is a read, or a write with errors, it is done.
441 	 */
442 	if ((beio->bio_cmd == BIO_READ)
443 	 || ((io->io_hdr.flags & CTL_FLAG_ABORT) != 0)
444 	 || ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE)) {
445 		ctl_complete_beio(beio);
446 		return (0);
447 	}
448 
449 	/*
450 	 * At this point, we have a write and the DMA completed
451 	 * successfully.  We now have to queue it to the task queue to
452 	 * execute the backend I/O.  That is because we do blocking
453 	 * memory allocations, and in the file backing case, blocking I/O.
454 	 * This move done routine is generally called in the SIM's
455 	 * interrupt context, and therefore we cannot block.
456 	 */
457 	mtx_lock(&be_lun->queue_lock);
458 	/*
459 	 * XXX KDM make sure that links is okay to use at this point.
460 	 * Otherwise, we either need to add another field to ctl_io_hdr,
461 	 * or deal with resource allocation here.
462 	 */
463 	STAILQ_INSERT_TAIL(&be_lun->datamove_queue, &io->io_hdr, links);
464 	mtx_unlock(&be_lun->queue_lock);
465 
466 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
467 
468 	return (0);
469 }
470 
471 static void
472 ctl_be_block_biodone(struct bio *bio)
473 {
474 	struct ctl_be_block_io *beio;
475 	struct ctl_be_block_lun *be_lun;
476 	union ctl_io *io;
477 	int error;
478 
479 	beio = bio->bio_caller1;
480 	be_lun = beio->lun;
481 	io = beio->io;
482 
483 	DPRINTF("entered\n");
484 
485 	error = bio->bio_error;
486 	mtx_lock(&be_lun->io_lock);
487 	if (error != 0)
488 		beio->num_errors++;
489 
490 	beio->num_bios_done++;
491 
492 	/*
493 	 * XXX KDM will this cause WITNESS to complain?  Holding a lock
494 	 * during the free might cause it to complain.
495 	 */
496 	g_destroy_bio(bio);
497 
498 	/*
499 	 * If the send complete bit isn't set, or we aren't the last I/O to
500 	 * complete, then we're done.
501 	 */
502 	if ((beio->send_complete == 0)
503 	 || (beio->num_bios_done < beio->num_bios_sent)) {
504 		mtx_unlock(&be_lun->io_lock);
505 		return;
506 	}
507 
508 	/*
509 	 * At this point, we've verified that we are the last I/O to
510 	 * complete, so it's safe to drop the lock.
511 	 */
512 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
513 	    beio->ds_tag_type, beio->ds_trans_type,
514 	    /*now*/ NULL, /*then*/&beio->ds_t0);
515 	mtx_unlock(&be_lun->io_lock);
516 
517 	/*
518 	 * If there are any errors from the backing device, we fail the
519 	 * entire I/O with a medium error.
520 	 */
521 	if (beio->num_errors > 0) {
522 		if (error == EOPNOTSUPP) {
523 			ctl_set_invalid_opcode(&io->scsiio);
524 		} else if (error == ENOSPC || error == EDQUOT) {
525 			ctl_set_space_alloc_fail(&io->scsiio);
526 		} else if (beio->bio_cmd == BIO_FLUSH) {
527 			/* XXX KDM is there is a better error here? */
528 			ctl_set_internal_failure(&io->scsiio,
529 						 /*sks_valid*/ 1,
530 						 /*retry_count*/ 0xbad2);
531 		} else
532 			ctl_set_medium_error(&io->scsiio);
533 		ctl_complete_beio(beio);
534 		return;
535 	}
536 
537 	/*
538 	 * If this is a write, a flush, a delete or verify, we're all done.
539 	 * If this is a read, we can now send the data to the user.
540 	 */
541 	if ((beio->bio_cmd == BIO_WRITE)
542 	 || (beio->bio_cmd == BIO_FLUSH)
543 	 || (beio->bio_cmd == BIO_DELETE)
544 	 || (ARGS(io)->flags & CTL_LLF_VERIFY)) {
545 		ctl_set_success(&io->scsiio);
546 		ctl_complete_beio(beio);
547 	} else {
548 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
549 		    beio->beio_cont == NULL)
550 			ctl_set_success(&io->scsiio);
551 #ifdef CTL_TIME_IO
552         	getbintime(&io->io_hdr.dma_start_bt);
553 #endif
554 		ctl_datamove(io);
555 	}
556 }
557 
558 static void
559 ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
560 			struct ctl_be_block_io *beio)
561 {
562 	union ctl_io *io = beio->io;
563 	struct mount *mountpoint;
564 	int error, lock_flags;
565 
566 	DPRINTF("entered\n");
567 
568 	binuptime(&beio->ds_t0);
569 	mtx_lock(&be_lun->io_lock);
570 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
571 	mtx_unlock(&be_lun->io_lock);
572 
573 	(void) vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
574 
575 	if (MNT_SHARED_WRITES(mountpoint)
576 	 || ((mountpoint == NULL)
577 	  && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
578 		lock_flags = LK_SHARED;
579 	else
580 		lock_flags = LK_EXCLUSIVE;
581 
582 	vn_lock(be_lun->vn, lock_flags | LK_RETRY);
583 
584 	error = VOP_FSYNC(be_lun->vn, MNT_WAIT, curthread);
585 	VOP_UNLOCK(be_lun->vn, 0);
586 
587 	vn_finished_write(mountpoint);
588 
589 	mtx_lock(&be_lun->io_lock);
590 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
591 	    beio->ds_tag_type, beio->ds_trans_type,
592 	    /*now*/ NULL, /*then*/&beio->ds_t0);
593 	mtx_unlock(&be_lun->io_lock);
594 
595 	if (error == 0)
596 		ctl_set_success(&io->scsiio);
597 	else {
598 		/* XXX KDM is there is a better error here? */
599 		ctl_set_internal_failure(&io->scsiio,
600 					 /*sks_valid*/ 1,
601 					 /*retry_count*/ 0xbad1);
602 	}
603 
604 	ctl_complete_beio(beio);
605 }
606 
607 SDT_PROBE_DEFINE1(cbb, kernel, read, file_start, "uint64_t");
608 SDT_PROBE_DEFINE1(cbb, kernel, write, file_start, "uint64_t");
609 SDT_PROBE_DEFINE1(cbb, kernel, read, file_done,"uint64_t");
610 SDT_PROBE_DEFINE1(cbb, kernel, write, file_done, "uint64_t");
611 
612 static void
613 ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
614 			   struct ctl_be_block_io *beio)
615 {
616 	struct ctl_be_block_filedata *file_data;
617 	union ctl_io *io;
618 	struct uio xuio;
619 	struct iovec *xiovec;
620 	int flags;
621 	int error, i;
622 
623 	DPRINTF("entered\n");
624 
625 	file_data = &be_lun->backend.file;
626 	io = beio->io;
627 	flags = 0;
628 	if (ARGS(io)->flags & CTL_LLF_DPO)
629 		flags |= IO_DIRECT;
630 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
631 		flags |= IO_SYNC;
632 
633 	bzero(&xuio, sizeof(xuio));
634 	if (beio->bio_cmd == BIO_READ) {
635 		SDT_PROBE(cbb, kernel, read, file_start, 0, 0, 0, 0, 0);
636 		xuio.uio_rw = UIO_READ;
637 	} else {
638 		SDT_PROBE(cbb, kernel, write, file_start, 0, 0, 0, 0, 0);
639 		xuio.uio_rw = UIO_WRITE;
640 	}
641 	xuio.uio_offset = beio->io_offset;
642 	xuio.uio_resid = beio->io_len;
643 	xuio.uio_segflg = UIO_SYSSPACE;
644 	xuio.uio_iov = beio->xiovecs;
645 	xuio.uio_iovcnt = beio->num_segs;
646 	xuio.uio_td = curthread;
647 
648 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
649 		xiovec->iov_base = beio->sg_segs[i].addr;
650 		xiovec->iov_len = beio->sg_segs[i].len;
651 	}
652 
653 	binuptime(&beio->ds_t0);
654 	mtx_lock(&be_lun->io_lock);
655 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
656 	mtx_unlock(&be_lun->io_lock);
657 
658 	if (beio->bio_cmd == BIO_READ) {
659 		vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
660 
661 		/*
662 		 * UFS pays attention to IO_DIRECT for reads.  If the
663 		 * DIRECTIO option is configured into the kernel, it calls
664 		 * ffs_rawread().  But that only works for single-segment
665 		 * uios with user space addresses.  In our case, with a
666 		 * kernel uio, it still reads into the buffer cache, but it
667 		 * will just try to release the buffer from the cache later
668 		 * on in ffs_read().
669 		 *
670 		 * ZFS does not pay attention to IO_DIRECT for reads.
671 		 *
672 		 * UFS does not pay attention to IO_SYNC for reads.
673 		 *
674 		 * ZFS pays attention to IO_SYNC (which translates into the
675 		 * Solaris define FRSYNC for zfs_read()) for reads.  It
676 		 * attempts to sync the file before reading.
677 		 *
678 		 * So, to attempt to provide some barrier semantics in the
679 		 * BIO_ORDERED case, set both IO_DIRECT and IO_SYNC.
680 		 */
681 		error = VOP_READ(be_lun->vn, &xuio, flags, file_data->cred);
682 
683 		VOP_UNLOCK(be_lun->vn, 0);
684 		SDT_PROBE(cbb, kernel, read, file_done, 0, 0, 0, 0, 0);
685 	} else {
686 		struct mount *mountpoint;
687 		int lock_flags;
688 
689 		(void)vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
690 
691 		if (MNT_SHARED_WRITES(mountpoint)
692 		 || ((mountpoint == NULL)
693 		  && MNT_SHARED_WRITES(be_lun->vn->v_mount)))
694 			lock_flags = LK_SHARED;
695 		else
696 			lock_flags = LK_EXCLUSIVE;
697 
698 		vn_lock(be_lun->vn, lock_flags | LK_RETRY);
699 
700 		/*
701 		 * UFS pays attention to IO_DIRECT for writes.  The write
702 		 * is done asynchronously.  (Normally the write would just
703 		 * get put into cache.
704 		 *
705 		 * UFS pays attention to IO_SYNC for writes.  It will
706 		 * attempt to write the buffer out synchronously if that
707 		 * flag is set.
708 		 *
709 		 * ZFS does not pay attention to IO_DIRECT for writes.
710 		 *
711 		 * ZFS pays attention to IO_SYNC (a.k.a. FSYNC or FRSYNC)
712 		 * for writes.  It will flush the transaction from the
713 		 * cache before returning.
714 		 *
715 		 * So if we've got the BIO_ORDERED flag set, we want
716 		 * IO_SYNC in either the UFS or ZFS case.
717 		 */
718 		error = VOP_WRITE(be_lun->vn, &xuio, flags, file_data->cred);
719 		VOP_UNLOCK(be_lun->vn, 0);
720 
721 		vn_finished_write(mountpoint);
722 		SDT_PROBE(cbb, kernel, write, file_done, 0, 0, 0, 0, 0);
723         }
724 
725 	mtx_lock(&be_lun->io_lock);
726 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
727 	    beio->ds_tag_type, beio->ds_trans_type,
728 	    /*now*/ NULL, /*then*/&beio->ds_t0);
729 	mtx_unlock(&be_lun->io_lock);
730 
731 	/*
732 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
733 	 * return the I/O to the user.
734 	 */
735 	if (error != 0) {
736 		char path_str[32];
737 
738 		ctl_scsi_path_string(io, path_str, sizeof(path_str));
739 		printf("%s%s command returned errno %d\n", path_str,
740 		       (beio->bio_cmd == BIO_READ) ? "READ" : "WRITE", error);
741 		if (error == ENOSPC || error == EDQUOT) {
742 			ctl_set_space_alloc_fail(&io->scsiio);
743 		} else
744 			ctl_set_medium_error(&io->scsiio);
745 		ctl_complete_beio(beio);
746 		return;
747 	}
748 
749 	/*
750 	 * If this is a write or a verify, we're all done.
751 	 * If this is a read, we can now send the data to the user.
752 	 */
753 	if ((beio->bio_cmd == BIO_WRITE) ||
754 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
755 		ctl_set_success(&io->scsiio);
756 		ctl_complete_beio(beio);
757 	} else {
758 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
759 		    beio->beio_cont == NULL)
760 			ctl_set_success(&io->scsiio);
761 #ifdef CTL_TIME_IO
762         	getbintime(&io->io_hdr.dma_start_bt);
763 #endif
764 		ctl_datamove(io);
765 	}
766 }
767 
768 static void
769 ctl_be_block_gls_file(struct ctl_be_block_lun *be_lun,
770 			struct ctl_be_block_io *beio)
771 {
772 	union ctl_io *io = beio->io;
773 	struct ctl_lba_len_flags *lbalen = ARGS(io);
774 	struct scsi_get_lba_status_data *data;
775 	off_t roff, off;
776 	int error, status;
777 
778 	DPRINTF("entered\n");
779 
780 	off = roff = ((off_t)lbalen->lba) << be_lun->blocksize_shift;
781 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
782 	error = VOP_IOCTL(be_lun->vn, FIOSEEKHOLE, &off,
783 	    0, curthread->td_ucred, curthread);
784 	if (error == 0 && off > roff)
785 		status = 0;	/* mapped up to off */
786 	else {
787 		error = VOP_IOCTL(be_lun->vn, FIOSEEKDATA, &off,
788 		    0, curthread->td_ucred, curthread);
789 		if (error == 0 && off > roff)
790 			status = 1;	/* deallocated up to off */
791 		else {
792 			status = 0;	/* unknown up to the end */
793 			off = be_lun->size_bytes;
794 		}
795 	}
796 	VOP_UNLOCK(be_lun->vn, 0);
797 
798 	off >>= be_lun->blocksize_shift;
799 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
800 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
801 	scsi_ulto4b(MIN(UINT32_MAX, off - lbalen->lba),
802 	    data->descr[0].length);
803 	data->descr[0].status = status;
804 
805 	ctl_complete_beio(beio);
806 }
807 
808 static uint64_t
809 ctl_be_block_getattr_file(struct ctl_be_block_lun *be_lun, const char *attrname)
810 {
811 	struct vattr		vattr;
812 	struct statfs		statfs;
813 	uint64_t		val;
814 	int			error;
815 
816 	val = UINT64_MAX;
817 	if (be_lun->vn == NULL)
818 		return (val);
819 	vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
820 	if (strcmp(attrname, "blocksused") == 0) {
821 		error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
822 		if (error == 0)
823 			val = vattr.va_bytes >> be_lun->blocksize_shift;
824 	}
825 	if (strcmp(attrname, "blocksavail") == 0 &&
826 	    (be_lun->vn->v_iflag & VI_DOOMED) == 0) {
827 		error = VFS_STATFS(be_lun->vn->v_mount, &statfs);
828 		if (error == 0)
829 			val = (statfs.f_bavail * statfs.f_bsize) >>
830 			    be_lun->blocksize_shift;
831 	}
832 	VOP_UNLOCK(be_lun->vn, 0);
833 	return (val);
834 }
835 
836 static void
837 ctl_be_block_dispatch_zvol(struct ctl_be_block_lun *be_lun,
838 			   struct ctl_be_block_io *beio)
839 {
840 	struct ctl_be_block_devdata *dev_data;
841 	union ctl_io *io;
842 	struct uio xuio;
843 	struct iovec *xiovec;
844 	int flags;
845 	int error, i;
846 
847 	DPRINTF("entered\n");
848 
849 	dev_data = &be_lun->backend.dev;
850 	io = beio->io;
851 	flags = 0;
852 	if (ARGS(io)->flags & CTL_LLF_DPO)
853 		flags |= IO_DIRECT;
854 	if (beio->bio_cmd == BIO_WRITE && ARGS(io)->flags & CTL_LLF_FUA)
855 		flags |= IO_SYNC;
856 
857 	bzero(&xuio, sizeof(xuio));
858 	if (beio->bio_cmd == BIO_READ) {
859 		SDT_PROBE(cbb, kernel, read, file_start, 0, 0, 0, 0, 0);
860 		xuio.uio_rw = UIO_READ;
861 	} else {
862 		SDT_PROBE(cbb, kernel, write, file_start, 0, 0, 0, 0, 0);
863 		xuio.uio_rw = UIO_WRITE;
864 	}
865 	xuio.uio_offset = beio->io_offset;
866 	xuio.uio_resid = beio->io_len;
867 	xuio.uio_segflg = UIO_SYSSPACE;
868 	xuio.uio_iov = beio->xiovecs;
869 	xuio.uio_iovcnt = beio->num_segs;
870 	xuio.uio_td = curthread;
871 
872 	for (i = 0, xiovec = xuio.uio_iov; i < xuio.uio_iovcnt; i++, xiovec++) {
873 		xiovec->iov_base = beio->sg_segs[i].addr;
874 		xiovec->iov_len = beio->sg_segs[i].len;
875 	}
876 
877 	binuptime(&beio->ds_t0);
878 	mtx_lock(&be_lun->io_lock);
879 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
880 	mtx_unlock(&be_lun->io_lock);
881 
882 	if (beio->bio_cmd == BIO_READ) {
883 		error = (*dev_data->csw->d_read)(dev_data->cdev, &xuio, flags);
884 		SDT_PROBE(cbb, kernel, read, file_done, 0, 0, 0, 0, 0);
885 	} else {
886 		error = (*dev_data->csw->d_write)(dev_data->cdev, &xuio, flags);
887 		SDT_PROBE(cbb, kernel, write, file_done, 0, 0, 0, 0, 0);
888 	}
889 
890 	mtx_lock(&be_lun->io_lock);
891 	devstat_end_transaction(beio->lun->disk_stats, beio->io_len,
892 	    beio->ds_tag_type, beio->ds_trans_type,
893 	    /*now*/ NULL, /*then*/&beio->ds_t0);
894 	mtx_unlock(&be_lun->io_lock);
895 
896 	/*
897 	 * If we got an error, set the sense data to "MEDIUM ERROR" and
898 	 * return the I/O to the user.
899 	 */
900 	if (error != 0) {
901 		if (error == ENOSPC || error == EDQUOT) {
902 			ctl_set_space_alloc_fail(&io->scsiio);
903 		} else
904 			ctl_set_medium_error(&io->scsiio);
905 		ctl_complete_beio(beio);
906 		return;
907 	}
908 
909 	/*
910 	 * If this is a write or a verify, we're all done.
911 	 * If this is a read, we can now send the data to the user.
912 	 */
913 	if ((beio->bio_cmd == BIO_WRITE) ||
914 	    (ARGS(io)->flags & CTL_LLF_VERIFY)) {
915 		ctl_set_success(&io->scsiio);
916 		ctl_complete_beio(beio);
917 	} else {
918 		if ((ARGS(io)->flags & CTL_LLF_READ) &&
919 		    beio->beio_cont == NULL)
920 			ctl_set_success(&io->scsiio);
921 #ifdef CTL_TIME_IO
922         	getbintime(&io->io_hdr.dma_start_bt);
923 #endif
924 		ctl_datamove(io);
925 	}
926 }
927 
928 static void
929 ctl_be_block_gls_zvol(struct ctl_be_block_lun *be_lun,
930 			struct ctl_be_block_io *beio)
931 {
932 	struct ctl_be_block_devdata *dev_data = &be_lun->backend.dev;
933 	union ctl_io *io = beio->io;
934 	struct ctl_lba_len_flags *lbalen = ARGS(io);
935 	struct scsi_get_lba_status_data *data;
936 	off_t roff, off;
937 	int error, status;
938 
939 	DPRINTF("entered\n");
940 
941 	off = roff = ((off_t)lbalen->lba) << be_lun->blocksize_shift;
942 	error = (*dev_data->csw->d_ioctl)(dev_data->cdev, FIOSEEKHOLE,
943 	    (caddr_t)&off, FREAD, curthread);
944 	if (error == 0 && off > roff)
945 		status = 0;	/* mapped up to off */
946 	else {
947 		error = (*dev_data->csw->d_ioctl)(dev_data->cdev, FIOSEEKDATA,
948 		    (caddr_t)&off, FREAD, curthread);
949 		if (error == 0 && off > roff)
950 			status = 1;	/* deallocated up to off */
951 		else {
952 			status = 0;	/* unknown up to the end */
953 			off = be_lun->size_bytes;
954 		}
955 	}
956 
957 	off >>= be_lun->blocksize_shift;
958 	data = (struct scsi_get_lba_status_data *)io->scsiio.kern_data_ptr;
959 	scsi_u64to8b(lbalen->lba, data->descr[0].addr);
960 	scsi_ulto4b(MIN(UINT32_MAX, off - lbalen->lba),
961 	    data->descr[0].length);
962 	data->descr[0].status = status;
963 
964 	ctl_complete_beio(beio);
965 }
966 
967 static void
968 ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
969 		       struct ctl_be_block_io *beio)
970 {
971 	struct bio *bio;
972 	union ctl_io *io;
973 	struct ctl_be_block_devdata *dev_data;
974 
975 	dev_data = &be_lun->backend.dev;
976 	io = beio->io;
977 
978 	DPRINTF("entered\n");
979 
980 	/* This can't fail, it's a blocking allocation. */
981 	bio = g_alloc_bio();
982 
983 	bio->bio_cmd	    = BIO_FLUSH;
984 	bio->bio_flags	   |= BIO_ORDERED;
985 	bio->bio_dev	    = dev_data->cdev;
986 	bio->bio_offset	    = 0;
987 	bio->bio_data	    = 0;
988 	bio->bio_done	    = ctl_be_block_biodone;
989 	bio->bio_caller1    = beio;
990 	bio->bio_pblkno	    = 0;
991 
992 	/*
993 	 * We don't need to acquire the LUN lock here, because we are only
994 	 * sending one bio, and so there is no other context to synchronize
995 	 * with.
996 	 */
997 	beio->num_bios_sent = 1;
998 	beio->send_complete = 1;
999 
1000 	binuptime(&beio->ds_t0);
1001 	mtx_lock(&be_lun->io_lock);
1002 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1003 	mtx_unlock(&be_lun->io_lock);
1004 
1005 	(*dev_data->csw->d_strategy)(bio);
1006 }
1007 
1008 static void
1009 ctl_be_block_unmap_dev_range(struct ctl_be_block_lun *be_lun,
1010 		       struct ctl_be_block_io *beio,
1011 		       uint64_t off, uint64_t len, int last)
1012 {
1013 	struct bio *bio;
1014 	struct ctl_be_block_devdata *dev_data;
1015 	uint64_t maxlen;
1016 
1017 	dev_data = &be_lun->backend.dev;
1018 	maxlen = LONG_MAX - (LONG_MAX % be_lun->blocksize);
1019 	while (len > 0) {
1020 		bio = g_alloc_bio();
1021 		bio->bio_cmd	    = BIO_DELETE;
1022 		bio->bio_dev	    = dev_data->cdev;
1023 		bio->bio_offset	    = off;
1024 		bio->bio_length	    = MIN(len, maxlen);
1025 		bio->bio_data	    = 0;
1026 		bio->bio_done	    = ctl_be_block_biodone;
1027 		bio->bio_caller1    = beio;
1028 		bio->bio_pblkno     = off / be_lun->blocksize;
1029 
1030 		off += bio->bio_length;
1031 		len -= bio->bio_length;
1032 
1033 		mtx_lock(&be_lun->io_lock);
1034 		beio->num_bios_sent++;
1035 		if (last && len == 0)
1036 			beio->send_complete = 1;
1037 		mtx_unlock(&be_lun->io_lock);
1038 
1039 		(*dev_data->csw->d_strategy)(bio);
1040 	}
1041 }
1042 
1043 static void
1044 ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
1045 		       struct ctl_be_block_io *beio)
1046 {
1047 	union ctl_io *io;
1048 	struct ctl_be_block_devdata *dev_data;
1049 	struct ctl_ptr_len_flags *ptrlen;
1050 	struct scsi_unmap_desc *buf, *end;
1051 	uint64_t len;
1052 
1053 	dev_data = &be_lun->backend.dev;
1054 	io = beio->io;
1055 
1056 	DPRINTF("entered\n");
1057 
1058 	binuptime(&beio->ds_t0);
1059 	mtx_lock(&be_lun->io_lock);
1060 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1061 	mtx_unlock(&be_lun->io_lock);
1062 
1063 	if (beio->io_offset == -1) {
1064 		beio->io_len = 0;
1065 		ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1066 		buf = (struct scsi_unmap_desc *)ptrlen->ptr;
1067 		end = buf + ptrlen->len / sizeof(*buf);
1068 		for (; buf < end; buf++) {
1069 			len = (uint64_t)scsi_4btoul(buf->length) *
1070 			    be_lun->blocksize;
1071 			beio->io_len += len;
1072 			ctl_be_block_unmap_dev_range(be_lun, beio,
1073 			    scsi_8btou64(buf->lba) * be_lun->blocksize, len,
1074 			    (end - buf < 2) ? TRUE : FALSE);
1075 		}
1076 	} else
1077 		ctl_be_block_unmap_dev_range(be_lun, beio,
1078 		    beio->io_offset, beio->io_len, TRUE);
1079 }
1080 
1081 static void
1082 ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
1083 			  struct ctl_be_block_io *beio)
1084 {
1085 	TAILQ_HEAD(, bio) queue = TAILQ_HEAD_INITIALIZER(queue);
1086 	int i;
1087 	struct bio *bio;
1088 	struct ctl_be_block_devdata *dev_data;
1089 	off_t cur_offset;
1090 	int max_iosize;
1091 
1092 	DPRINTF("entered\n");
1093 
1094 	dev_data = &be_lun->backend.dev;
1095 
1096 	/*
1097 	 * We have to limit our I/O size to the maximum supported by the
1098 	 * backend device.  Hopefully it is MAXPHYS.  If the driver doesn't
1099 	 * set it properly, use DFLTPHYS.
1100 	 */
1101 	max_iosize = dev_data->cdev->si_iosize_max;
1102 	if (max_iosize < PAGE_SIZE)
1103 		max_iosize = DFLTPHYS;
1104 
1105 	cur_offset = beio->io_offset;
1106 	for (i = 0; i < beio->num_segs; i++) {
1107 		size_t cur_size;
1108 		uint8_t *cur_ptr;
1109 
1110 		cur_size = beio->sg_segs[i].len;
1111 		cur_ptr = beio->sg_segs[i].addr;
1112 
1113 		while (cur_size > 0) {
1114 			/* This can't fail, it's a blocking allocation. */
1115 			bio = g_alloc_bio();
1116 
1117 			KASSERT(bio != NULL, ("g_alloc_bio() failed!\n"));
1118 
1119 			bio->bio_cmd = beio->bio_cmd;
1120 			bio->bio_dev = dev_data->cdev;
1121 			bio->bio_caller1 = beio;
1122 			bio->bio_length = min(cur_size, max_iosize);
1123 			bio->bio_offset = cur_offset;
1124 			bio->bio_data = cur_ptr;
1125 			bio->bio_done = ctl_be_block_biodone;
1126 			bio->bio_pblkno = cur_offset / be_lun->blocksize;
1127 
1128 			cur_offset += bio->bio_length;
1129 			cur_ptr += bio->bio_length;
1130 			cur_size -= bio->bio_length;
1131 
1132 			TAILQ_INSERT_TAIL(&queue, bio, bio_queue);
1133 			beio->num_bios_sent++;
1134 		}
1135 	}
1136 	binuptime(&beio->ds_t0);
1137 	mtx_lock(&be_lun->io_lock);
1138 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
1139 	beio->send_complete = 1;
1140 	mtx_unlock(&be_lun->io_lock);
1141 
1142 	/*
1143 	 * Fire off all allocated requests!
1144 	 */
1145 	while ((bio = TAILQ_FIRST(&queue)) != NULL) {
1146 		TAILQ_REMOVE(&queue, bio, bio_queue);
1147 		(*dev_data->csw->d_strategy)(bio);
1148 	}
1149 }
1150 
1151 static uint64_t
1152 ctl_be_block_getattr_dev(struct ctl_be_block_lun *be_lun, const char *attrname)
1153 {
1154 	struct ctl_be_block_devdata	*dev_data = &be_lun->backend.dev;
1155 	struct diocgattr_arg	arg;
1156 	int			error;
1157 
1158 	if (dev_data->csw == NULL || dev_data->csw->d_ioctl == NULL)
1159 		return (UINT64_MAX);
1160 	strlcpy(arg.name, attrname, sizeof(arg.name));
1161 	arg.len = sizeof(arg.value.off);
1162 	error = dev_data->csw->d_ioctl(dev_data->cdev,
1163 	    DIOCGATTR, (caddr_t)&arg, FREAD, curthread);
1164 	if (error != 0)
1165 		return (UINT64_MAX);
1166 	return (arg.value.off);
1167 }
1168 
1169 static void
1170 ctl_be_block_cw_done_ws(struct ctl_be_block_io *beio)
1171 {
1172 	union ctl_io *io;
1173 
1174 	io = beio->io;
1175 	ctl_free_beio(beio);
1176 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1177 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1178 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1179 		ctl_config_write_done(io);
1180 		return;
1181 	}
1182 
1183 	ctl_be_block_config_write(io);
1184 }
1185 
1186 static void
1187 ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *be_lun,
1188 			    union ctl_io *io)
1189 {
1190 	struct ctl_be_block_io *beio;
1191 	struct ctl_be_block_softc *softc;
1192 	struct ctl_lba_len_flags *lbalen;
1193 	uint64_t len_left, lba;
1194 	uint32_t pb, pbo, adj;
1195 	int i, seglen;
1196 	uint8_t *buf, *end;
1197 
1198 	DPRINTF("entered\n");
1199 
1200 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1201 	softc = be_lun->softc;
1202 	lbalen = ARGS(beio->io);
1203 
1204 	if (lbalen->flags & ~(SWS_LBDATA | SWS_UNMAP | SWS_ANCHOR | SWS_NDOB) ||
1205 	    (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR) && be_lun->unmap == NULL)) {
1206 		ctl_free_beio(beio);
1207 		ctl_set_invalid_field(&io->scsiio,
1208 				      /*sks_valid*/ 1,
1209 				      /*command*/ 1,
1210 				      /*field*/ 1,
1211 				      /*bit_valid*/ 0,
1212 				      /*bit*/ 0);
1213 		ctl_config_write_done(io);
1214 		return;
1215 	}
1216 
1217 	switch (io->scsiio.tag_type) {
1218 	case CTL_TAG_ORDERED:
1219 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1220 		break;
1221 	case CTL_TAG_HEAD_OF_QUEUE:
1222 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1223 		break;
1224 	case CTL_TAG_UNTAGGED:
1225 	case CTL_TAG_SIMPLE:
1226 	case CTL_TAG_ACA:
1227 	default:
1228 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1229 		break;
1230 	}
1231 
1232 	if (lbalen->flags & (SWS_UNMAP | SWS_ANCHOR)) {
1233 		beio->io_offset = lbalen->lba * be_lun->blocksize;
1234 		beio->io_len = (uint64_t)lbalen->len * be_lun->blocksize;
1235 		beio->bio_cmd = BIO_DELETE;
1236 		beio->ds_trans_type = DEVSTAT_FREE;
1237 
1238 		be_lun->unmap(be_lun, beio);
1239 		return;
1240 	}
1241 
1242 	beio->bio_cmd = BIO_WRITE;
1243 	beio->ds_trans_type = DEVSTAT_WRITE;
1244 
1245 	DPRINTF("WRITE SAME at LBA %jx len %u\n",
1246 	       (uintmax_t)lbalen->lba, lbalen->len);
1247 
1248 	pb = be_lun->blocksize << be_lun->pblockexp;
1249 	if (be_lun->pblockoff > 0)
1250 		pbo = pb - be_lun->blocksize * be_lun->pblockoff;
1251 	else
1252 		pbo = 0;
1253 	len_left = (uint64_t)lbalen->len * be_lun->blocksize;
1254 	for (i = 0, lba = 0; i < CTLBLK_MAX_SEGS && len_left > 0; i++) {
1255 
1256 		/*
1257 		 * Setup the S/G entry for this chunk.
1258 		 */
1259 		seglen = MIN(CTLBLK_MAX_SEG, len_left);
1260 		if (pb > be_lun->blocksize) {
1261 			adj = ((lbalen->lba + lba) * be_lun->blocksize +
1262 			    seglen - pbo) % pb;
1263 			if (seglen > adj)
1264 				seglen -= adj;
1265 			else
1266 				seglen -= seglen % be_lun->blocksize;
1267 		} else
1268 			seglen -= seglen % be_lun->blocksize;
1269 		beio->sg_segs[i].len = seglen;
1270 		beio->sg_segs[i].addr = uma_zalloc(be_lun->lun_zone, M_WAITOK);
1271 
1272 		DPRINTF("segment %d addr %p len %zd\n", i,
1273 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1274 
1275 		beio->num_segs++;
1276 		len_left -= seglen;
1277 
1278 		buf = beio->sg_segs[i].addr;
1279 		end = buf + seglen;
1280 		for (; buf < end; buf += be_lun->blocksize) {
1281 			memcpy(buf, io->scsiio.kern_data_ptr, be_lun->blocksize);
1282 			if (lbalen->flags & SWS_LBDATA)
1283 				scsi_ulto4b(lbalen->lba + lba, buf);
1284 			lba++;
1285 		}
1286 	}
1287 
1288 	beio->io_offset = lbalen->lba * be_lun->blocksize;
1289 	beio->io_len = lba * be_lun->blocksize;
1290 
1291 	/* We can not do all in one run. Correct and schedule rerun. */
1292 	if (len_left > 0) {
1293 		lbalen->lba += lba;
1294 		lbalen->len -= lba;
1295 		beio->beio_cont = ctl_be_block_cw_done_ws;
1296 	}
1297 
1298 	be_lun->dispatch(be_lun, beio);
1299 }
1300 
1301 static void
1302 ctl_be_block_cw_dispatch_unmap(struct ctl_be_block_lun *be_lun,
1303 			    union ctl_io *io)
1304 {
1305 	struct ctl_be_block_io *beio;
1306 	struct ctl_be_block_softc *softc;
1307 	struct ctl_ptr_len_flags *ptrlen;
1308 
1309 	DPRINTF("entered\n");
1310 
1311 	beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1312 	softc = be_lun->softc;
1313 	ptrlen = (struct ctl_ptr_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
1314 
1315 	if ((ptrlen->flags & ~SU_ANCHOR) != 0 || be_lun->unmap == NULL) {
1316 		ctl_free_beio(beio);
1317 		ctl_set_invalid_field(&io->scsiio,
1318 				      /*sks_valid*/ 0,
1319 				      /*command*/ 1,
1320 				      /*field*/ 0,
1321 				      /*bit_valid*/ 0,
1322 				      /*bit*/ 0);
1323 		ctl_config_write_done(io);
1324 		return;
1325 	}
1326 
1327 	switch (io->scsiio.tag_type) {
1328 	case CTL_TAG_ORDERED:
1329 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1330 		break;
1331 	case CTL_TAG_HEAD_OF_QUEUE:
1332 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1333 		break;
1334 	case CTL_TAG_UNTAGGED:
1335 	case CTL_TAG_SIMPLE:
1336 	case CTL_TAG_ACA:
1337 	default:
1338 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1339 		break;
1340 	}
1341 
1342 	beio->io_len = 0;
1343 	beio->io_offset = -1;
1344 
1345 	beio->bio_cmd = BIO_DELETE;
1346 	beio->ds_trans_type = DEVSTAT_FREE;
1347 
1348 	DPRINTF("UNMAP\n");
1349 
1350 	be_lun->unmap(be_lun, beio);
1351 }
1352 
1353 static void
1354 ctl_be_block_cr_done(struct ctl_be_block_io *beio)
1355 {
1356 	union ctl_io *io;
1357 
1358 	io = beio->io;
1359 	ctl_free_beio(beio);
1360 	ctl_config_read_done(io);
1361 }
1362 
1363 static void
1364 ctl_be_block_cr_dispatch(struct ctl_be_block_lun *be_lun,
1365 			 union ctl_io *io)
1366 {
1367 	struct ctl_be_block_io *beio;
1368 	struct ctl_be_block_softc *softc;
1369 
1370 	DPRINTF("entered\n");
1371 
1372 	softc = be_lun->softc;
1373 	beio = ctl_alloc_beio(softc);
1374 	beio->io = io;
1375 	beio->lun = be_lun;
1376 	beio->beio_cont = ctl_be_block_cr_done;
1377 	PRIV(io)->ptr = (void *)beio;
1378 
1379 	switch (io->scsiio.cdb[0]) {
1380 	case SERVICE_ACTION_IN:		/* GET LBA STATUS */
1381 		beio->bio_cmd = -1;
1382 		beio->ds_trans_type = DEVSTAT_NO_DATA;
1383 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1384 		beio->io_len = 0;
1385 		if (be_lun->get_lba_status)
1386 			be_lun->get_lba_status(be_lun, beio);
1387 		else
1388 			ctl_be_block_cr_done(beio);
1389 		break;
1390 	default:
1391 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1392 		break;
1393 	}
1394 }
1395 
1396 static void
1397 ctl_be_block_cw_done(struct ctl_be_block_io *beio)
1398 {
1399 	union ctl_io *io;
1400 
1401 	io = beio->io;
1402 	ctl_free_beio(beio);
1403 	ctl_config_write_done(io);
1404 }
1405 
1406 static void
1407 ctl_be_block_cw_dispatch(struct ctl_be_block_lun *be_lun,
1408 			 union ctl_io *io)
1409 {
1410 	struct ctl_be_block_io *beio;
1411 	struct ctl_be_block_softc *softc;
1412 
1413 	DPRINTF("entered\n");
1414 
1415 	softc = be_lun->softc;
1416 	beio = ctl_alloc_beio(softc);
1417 	beio->io = io;
1418 	beio->lun = be_lun;
1419 	beio->beio_cont = ctl_be_block_cw_done;
1420 	PRIV(io)->ptr = (void *)beio;
1421 
1422 	switch (io->scsiio.cdb[0]) {
1423 	case SYNCHRONIZE_CACHE:
1424 	case SYNCHRONIZE_CACHE_16:
1425 		beio->bio_cmd = BIO_FLUSH;
1426 		beio->ds_trans_type = DEVSTAT_NO_DATA;
1427 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1428 		beio->io_len = 0;
1429 		be_lun->lun_flush(be_lun, beio);
1430 		break;
1431 	case WRITE_SAME_10:
1432 	case WRITE_SAME_16:
1433 		ctl_be_block_cw_dispatch_ws(be_lun, io);
1434 		break;
1435 	case UNMAP:
1436 		ctl_be_block_cw_dispatch_unmap(be_lun, io);
1437 		break;
1438 	default:
1439 		panic("Unhandled CDB type %#x", io->scsiio.cdb[0]);
1440 		break;
1441 	}
1442 }
1443 
1444 SDT_PROBE_DEFINE1(cbb, kernel, read, start, "uint64_t");
1445 SDT_PROBE_DEFINE1(cbb, kernel, write, start, "uint64_t");
1446 SDT_PROBE_DEFINE1(cbb, kernel, read, alloc_done, "uint64_t");
1447 SDT_PROBE_DEFINE1(cbb, kernel, write, alloc_done, "uint64_t");
1448 
1449 static void
1450 ctl_be_block_next(struct ctl_be_block_io *beio)
1451 {
1452 	struct ctl_be_block_lun *be_lun;
1453 	union ctl_io *io;
1454 
1455 	io = beio->io;
1456 	be_lun = beio->lun;
1457 	ctl_free_beio(beio);
1458 	if ((io->io_hdr.flags & CTL_FLAG_ABORT) ||
1459 	    ((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE &&
1460 	     (io->io_hdr.status & CTL_STATUS_MASK) != CTL_SUCCESS)) {
1461 		ctl_data_submit_done(io);
1462 		return;
1463 	}
1464 
1465 	io->io_hdr.status &= ~CTL_STATUS_MASK;
1466 	io->io_hdr.status |= CTL_STATUS_NONE;
1467 
1468 	mtx_lock(&be_lun->queue_lock);
1469 	/*
1470 	 * XXX KDM make sure that links is okay to use at this point.
1471 	 * Otherwise, we either need to add another field to ctl_io_hdr,
1472 	 * or deal with resource allocation here.
1473 	 */
1474 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1475 	mtx_unlock(&be_lun->queue_lock);
1476 
1477 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1478 }
1479 
1480 static void
1481 ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
1482 			   union ctl_io *io)
1483 {
1484 	struct ctl_be_block_io *beio;
1485 	struct ctl_be_block_softc *softc;
1486 	struct ctl_lba_len_flags *lbalen;
1487 	struct ctl_ptr_len_flags *bptrlen;
1488 	uint64_t len_left, lbas;
1489 	int i;
1490 
1491 	softc = be_lun->softc;
1492 
1493 	DPRINTF("entered\n");
1494 
1495 	lbalen = ARGS(io);
1496 	if (lbalen->flags & CTL_LLF_WRITE) {
1497 		SDT_PROBE(cbb, kernel, write, start, 0, 0, 0, 0, 0);
1498 	} else {
1499 		SDT_PROBE(cbb, kernel, read, start, 0, 0, 0, 0, 0);
1500 	}
1501 
1502 	beio = ctl_alloc_beio(softc);
1503 	beio->io = io;
1504 	beio->lun = be_lun;
1505 	bptrlen = PRIV(io);
1506 	bptrlen->ptr = (void *)beio;
1507 
1508 	switch (io->scsiio.tag_type) {
1509 	case CTL_TAG_ORDERED:
1510 		beio->ds_tag_type = DEVSTAT_TAG_ORDERED;
1511 		break;
1512 	case CTL_TAG_HEAD_OF_QUEUE:
1513 		beio->ds_tag_type = DEVSTAT_TAG_HEAD;
1514 		break;
1515 	case CTL_TAG_UNTAGGED:
1516 	case CTL_TAG_SIMPLE:
1517 	case CTL_TAG_ACA:
1518 	default:
1519 		beio->ds_tag_type = DEVSTAT_TAG_SIMPLE;
1520 		break;
1521 	}
1522 
1523 	if (lbalen->flags & CTL_LLF_WRITE) {
1524 		beio->bio_cmd = BIO_WRITE;
1525 		beio->ds_trans_type = DEVSTAT_WRITE;
1526 	} else {
1527 		beio->bio_cmd = BIO_READ;
1528 		beio->ds_trans_type = DEVSTAT_READ;
1529 	}
1530 
1531 	DPRINTF("%s at LBA %jx len %u @%ju\n",
1532 	       (beio->bio_cmd == BIO_READ) ? "READ" : "WRITE",
1533 	       (uintmax_t)lbalen->lba, lbalen->len, bptrlen->len);
1534 	if (lbalen->flags & CTL_LLF_COMPARE)
1535 		lbas = CTLBLK_HALF_IO_SIZE;
1536 	else
1537 		lbas = CTLBLK_MAX_IO_SIZE;
1538 	lbas = MIN(lbalen->len - bptrlen->len, lbas / be_lun->blocksize);
1539 	beio->io_offset = (lbalen->lba + bptrlen->len) * be_lun->blocksize;
1540 	beio->io_len = lbas * be_lun->blocksize;
1541 	bptrlen->len += lbas;
1542 
1543 	for (i = 0, len_left = beio->io_len; len_left > 0; i++) {
1544 		KASSERT(i < CTLBLK_MAX_SEGS, ("Too many segs (%d >= %d)",
1545 		    i, CTLBLK_MAX_SEGS));
1546 
1547 		/*
1548 		 * Setup the S/G entry for this chunk.
1549 		 */
1550 		beio->sg_segs[i].len = min(CTLBLK_MAX_SEG, len_left);
1551 		beio->sg_segs[i].addr = uma_zalloc(be_lun->lun_zone, M_WAITOK);
1552 
1553 		DPRINTF("segment %d addr %p len %zd\n", i,
1554 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
1555 
1556 		/* Set up second segment for compare operation. */
1557 		if (lbalen->flags & CTL_LLF_COMPARE) {
1558 			beio->sg_segs[i + CTLBLK_HALF_SEGS].len =
1559 			    beio->sg_segs[i].len;
1560 			beio->sg_segs[i + CTLBLK_HALF_SEGS].addr =
1561 			    uma_zalloc(be_lun->lun_zone, M_WAITOK);
1562 		}
1563 
1564 		beio->num_segs++;
1565 		len_left -= beio->sg_segs[i].len;
1566 	}
1567 	if (bptrlen->len < lbalen->len)
1568 		beio->beio_cont = ctl_be_block_next;
1569 	io->scsiio.be_move_done = ctl_be_block_move_done;
1570 	/* For compare we have separate S/G lists for read and datamove. */
1571 	if (lbalen->flags & CTL_LLF_COMPARE)
1572 		io->scsiio.kern_data_ptr = (uint8_t *)&beio->sg_segs[CTLBLK_HALF_SEGS];
1573 	else
1574 		io->scsiio.kern_data_ptr = (uint8_t *)beio->sg_segs;
1575 	io->scsiio.kern_data_len = beio->io_len;
1576 	io->scsiio.kern_data_resid = 0;
1577 	io->scsiio.kern_sg_entries = beio->num_segs;
1578 	io->io_hdr.flags |= CTL_FLAG_ALLOCATED | CTL_FLAG_KDPTR_SGLIST;
1579 
1580 	/*
1581 	 * For the read case, we need to read the data into our buffers and
1582 	 * then we can send it back to the user.  For the write case, we
1583 	 * need to get the data from the user first.
1584 	 */
1585 	if (beio->bio_cmd == BIO_READ) {
1586 		SDT_PROBE(cbb, kernel, read, alloc_done, 0, 0, 0, 0, 0);
1587 		be_lun->dispatch(be_lun, beio);
1588 	} else {
1589 		SDT_PROBE(cbb, kernel, write, alloc_done, 0, 0, 0, 0, 0);
1590 #ifdef CTL_TIME_IO
1591         	getbintime(&io->io_hdr.dma_start_bt);
1592 #endif
1593 		ctl_datamove(io);
1594 	}
1595 }
1596 
1597 static void
1598 ctl_be_block_worker(void *context, int pending)
1599 {
1600 	struct ctl_be_block_lun *be_lun;
1601 	struct ctl_be_block_softc *softc;
1602 	union ctl_io *io;
1603 
1604 	be_lun = (struct ctl_be_block_lun *)context;
1605 	softc = be_lun->softc;
1606 
1607 	DPRINTF("entered\n");
1608 
1609 	mtx_lock(&be_lun->queue_lock);
1610 	for (;;) {
1611 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->datamove_queue);
1612 		if (io != NULL) {
1613 			struct ctl_be_block_io *beio;
1614 
1615 			DPRINTF("datamove queue\n");
1616 
1617 			STAILQ_REMOVE(&be_lun->datamove_queue, &io->io_hdr,
1618 				      ctl_io_hdr, links);
1619 
1620 			mtx_unlock(&be_lun->queue_lock);
1621 
1622 			beio = (struct ctl_be_block_io *)PRIV(io)->ptr;
1623 
1624 			be_lun->dispatch(be_lun, beio);
1625 
1626 			mtx_lock(&be_lun->queue_lock);
1627 			continue;
1628 		}
1629 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_write_queue);
1630 		if (io != NULL) {
1631 			DPRINTF("config write queue\n");
1632 			STAILQ_REMOVE(&be_lun->config_write_queue, &io->io_hdr,
1633 				      ctl_io_hdr, links);
1634 			mtx_unlock(&be_lun->queue_lock);
1635 			ctl_be_block_cw_dispatch(be_lun, io);
1636 			mtx_lock(&be_lun->queue_lock);
1637 			continue;
1638 		}
1639 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->config_read_queue);
1640 		if (io != NULL) {
1641 			DPRINTF("config read queue\n");
1642 			STAILQ_REMOVE(&be_lun->config_read_queue, &io->io_hdr,
1643 				      ctl_io_hdr, links);
1644 			mtx_unlock(&be_lun->queue_lock);
1645 			ctl_be_block_cr_dispatch(be_lun, io);
1646 			mtx_lock(&be_lun->queue_lock);
1647 			continue;
1648 		}
1649 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->input_queue);
1650 		if (io != NULL) {
1651 			DPRINTF("input queue\n");
1652 
1653 			STAILQ_REMOVE(&be_lun->input_queue, &io->io_hdr,
1654 				      ctl_io_hdr, links);
1655 			mtx_unlock(&be_lun->queue_lock);
1656 
1657 			/*
1658 			 * We must drop the lock, since this routine and
1659 			 * its children may sleep.
1660 			 */
1661 			ctl_be_block_dispatch(be_lun, io);
1662 
1663 			mtx_lock(&be_lun->queue_lock);
1664 			continue;
1665 		}
1666 
1667 		/*
1668 		 * If we get here, there is no work left in the queues, so
1669 		 * just break out and let the task queue go to sleep.
1670 		 */
1671 		break;
1672 	}
1673 	mtx_unlock(&be_lun->queue_lock);
1674 }
1675 
1676 /*
1677  * Entry point from CTL to the backend for I/O.  We queue everything to a
1678  * work thread, so this just puts the I/O on a queue and wakes up the
1679  * thread.
1680  */
1681 static int
1682 ctl_be_block_submit(union ctl_io *io)
1683 {
1684 	struct ctl_be_block_lun *be_lun;
1685 	struct ctl_be_lun *ctl_be_lun;
1686 
1687 	DPRINTF("entered\n");
1688 
1689 	ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
1690 		CTL_PRIV_BACKEND_LUN].ptr;
1691 	be_lun = (struct ctl_be_block_lun *)ctl_be_lun->be_lun;
1692 
1693 	/*
1694 	 * Make sure we only get SCSI I/O.
1695 	 */
1696 	KASSERT(io->io_hdr.io_type == CTL_IO_SCSI, ("Non-SCSI I/O (type "
1697 		"%#x) encountered", io->io_hdr.io_type));
1698 
1699 	PRIV(io)->len = 0;
1700 
1701 	mtx_lock(&be_lun->queue_lock);
1702 	/*
1703 	 * XXX KDM make sure that links is okay to use at this point.
1704 	 * Otherwise, we either need to add another field to ctl_io_hdr,
1705 	 * or deal with resource allocation here.
1706 	 */
1707 	STAILQ_INSERT_TAIL(&be_lun->input_queue, &io->io_hdr, links);
1708 	mtx_unlock(&be_lun->queue_lock);
1709 	taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
1710 
1711 	return (CTL_RETVAL_COMPLETE);
1712 }
1713 
1714 static int
1715 ctl_be_block_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
1716 			int flag, struct thread *td)
1717 {
1718 	struct ctl_be_block_softc *softc;
1719 	int error;
1720 
1721 	softc = &backend_block_softc;
1722 
1723 	error = 0;
1724 
1725 	switch (cmd) {
1726 	case CTL_LUN_REQ: {
1727 		struct ctl_lun_req *lun_req;
1728 
1729 		lun_req = (struct ctl_lun_req *)addr;
1730 
1731 		switch (lun_req->reqtype) {
1732 		case CTL_LUNREQ_CREATE:
1733 			error = ctl_be_block_create(softc, lun_req);
1734 			break;
1735 		case CTL_LUNREQ_RM:
1736 			error = ctl_be_block_rm(softc, lun_req);
1737 			break;
1738 		case CTL_LUNREQ_MODIFY:
1739 			error = ctl_be_block_modify(softc, lun_req);
1740 			break;
1741 		default:
1742 			lun_req->status = CTL_LUN_ERROR;
1743 			snprintf(lun_req->error_str, sizeof(lun_req->error_str),
1744 				 "invalid LUN request type %d",
1745 				 lun_req->reqtype);
1746 			break;
1747 		}
1748 		break;
1749 	}
1750 	default:
1751 		error = ENOTTY;
1752 		break;
1753 	}
1754 
1755 	return (error);
1756 }
1757 
1758 static int
1759 ctl_be_block_open_file(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1760 {
1761 	struct ctl_be_block_filedata *file_data;
1762 	struct ctl_lun_create_params *params;
1763 	char			     *value;
1764 	struct vattr		      vattr;
1765 	off_t			      ps, pss, po, pos, us, uss, uo, uos;
1766 	int			      error;
1767 
1768 	error = 0;
1769 	file_data = &be_lun->backend.file;
1770 	params = &be_lun->params;
1771 
1772 	be_lun->dev_type = CTL_BE_BLOCK_FILE;
1773 	be_lun->dispatch = ctl_be_block_dispatch_file;
1774 	be_lun->lun_flush = ctl_be_block_flush_file;
1775 	be_lun->get_lba_status = ctl_be_block_gls_file;
1776 	be_lun->getattr = ctl_be_block_getattr_file;
1777 
1778 	error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
1779 	if (error != 0) {
1780 		snprintf(req->error_str, sizeof(req->error_str),
1781 			 "error calling VOP_GETATTR() for file %s",
1782 			 be_lun->dev_path);
1783 		return (error);
1784 	}
1785 
1786 	/*
1787 	 * Verify that we have the ability to upgrade to exclusive
1788 	 * access on this file so we can trap errors at open instead
1789 	 * of reporting them during first access.
1790 	 */
1791 	if (VOP_ISLOCKED(be_lun->vn) != LK_EXCLUSIVE) {
1792 		vn_lock(be_lun->vn, LK_UPGRADE | LK_RETRY);
1793 		if (be_lun->vn->v_iflag & VI_DOOMED) {
1794 			error = EBADF;
1795 			snprintf(req->error_str, sizeof(req->error_str),
1796 				 "error locking file %s", be_lun->dev_path);
1797 			return (error);
1798 		}
1799 	}
1800 
1801 
1802 	file_data->cred = crhold(curthread->td_ucred);
1803 	if (params->lun_size_bytes != 0)
1804 		be_lun->size_bytes = params->lun_size_bytes;
1805 	else
1806 		be_lun->size_bytes = vattr.va_size;
1807 	/*
1808 	 * We set the multi thread flag for file operations because all
1809 	 * filesystems (in theory) are capable of allowing multiple readers
1810 	 * of a file at once.  So we want to get the maximum possible
1811 	 * concurrency.
1812 	 */
1813 	be_lun->flags |= CTL_BE_BLOCK_LUN_MULTI_THREAD;
1814 
1815 	/*
1816 	 * For files we can use any logical block size.  Prefer 512 bytes
1817 	 * for compatibility reasons.  If file's vattr.va_blocksize
1818 	 * (preferred I/O block size) is bigger and multiple to chosen
1819 	 * logical block size -- report it as physical block size.
1820 	 */
1821 	if (params->blocksize_bytes != 0)
1822 		be_lun->blocksize = params->blocksize_bytes;
1823 	else
1824 		be_lun->blocksize = 512;
1825 
1826 	us = ps = vattr.va_blocksize;
1827 	uo = po = 0;
1828 
1829 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "pblocksize");
1830 	if (value != NULL)
1831 		ctl_expand_number(value, &ps);
1832 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "pblockoffset");
1833 	if (value != NULL)
1834 		ctl_expand_number(value, &po);
1835 	pss = ps / be_lun->blocksize;
1836 	pos = po / be_lun->blocksize;
1837 	if ((pss > 0) && (pss * be_lun->blocksize == ps) && (pss >= pos) &&
1838 	    ((pss & (pss - 1)) == 0) && (pos * be_lun->blocksize == po)) {
1839 		be_lun->pblockexp = fls(pss) - 1;
1840 		be_lun->pblockoff = (pss - pos) % pss;
1841 	}
1842 
1843 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "ublocksize");
1844 	if (value != NULL)
1845 		ctl_expand_number(value, &us);
1846 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "ublockoffset");
1847 	if (value != NULL)
1848 		ctl_expand_number(value, &uo);
1849 	uss = us / be_lun->blocksize;
1850 	uos = uo / be_lun->blocksize;
1851 	if ((uss > 0) && (uss * be_lun->blocksize == us) && (uss >= uos) &&
1852 	    ((uss & (uss - 1)) == 0) && (uos * be_lun->blocksize == uo)) {
1853 		be_lun->ublockexp = fls(uss) - 1;
1854 		be_lun->ublockoff = (uss - uos) % uss;
1855 	}
1856 
1857 	/*
1858 	 * Sanity check.  The media size has to be at least one
1859 	 * sector long.
1860 	 */
1861 	if (be_lun->size_bytes < be_lun->blocksize) {
1862 		error = EINVAL;
1863 		snprintf(req->error_str, sizeof(req->error_str),
1864 			 "file %s size %ju < block size %u", be_lun->dev_path,
1865 			 (uintmax_t)be_lun->size_bytes, be_lun->blocksize);
1866 	}
1867 
1868 	be_lun->opttxferlen = CTLBLK_MAX_IO_SIZE / be_lun->blocksize;
1869 	return (error);
1870 }
1871 
1872 static int
1873 ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
1874 {
1875 	struct ctl_lun_create_params *params;
1876 	struct vattr		      vattr;
1877 	struct cdev		     *dev;
1878 	struct cdevsw		     *devsw;
1879 	char			     *value;
1880 	int			      error, atomic, maxio, unmap;
1881 	off_t			      ps, pss, po, pos, us, uss, uo, uos;
1882 
1883 	params = &be_lun->params;
1884 
1885 	be_lun->dev_type = CTL_BE_BLOCK_DEV;
1886 	be_lun->backend.dev.cdev = be_lun->vn->v_rdev;
1887 	be_lun->backend.dev.csw = dev_refthread(be_lun->backend.dev.cdev,
1888 					     &be_lun->backend.dev.dev_ref);
1889 	if (be_lun->backend.dev.csw == NULL)
1890 		panic("Unable to retrieve device switch");
1891 	if (strcmp(be_lun->backend.dev.csw->d_name, "zvol") == 0) {
1892 		be_lun->dispatch = ctl_be_block_dispatch_zvol;
1893 		be_lun->get_lba_status = ctl_be_block_gls_zvol;
1894 		atomic = maxio = CTLBLK_MAX_IO_SIZE;
1895 	} else {
1896 		be_lun->dispatch = ctl_be_block_dispatch_dev;
1897 		atomic = 0;
1898 		maxio = be_lun->backend.dev.cdev->si_iosize_max;
1899 		if (maxio <= 0)
1900 			maxio = DFLTPHYS;
1901 		if (maxio > CTLBLK_MAX_IO_SIZE)
1902 			maxio = CTLBLK_MAX_IO_SIZE;
1903 	}
1904 	be_lun->lun_flush = ctl_be_block_flush_dev;
1905 	be_lun->getattr = ctl_be_block_getattr_dev;
1906 
1907 	error = VOP_GETATTR(be_lun->vn, &vattr, NOCRED);
1908 	if (error) {
1909 		snprintf(req->error_str, sizeof(req->error_str),
1910 			 "error getting vnode attributes for device %s",
1911 			 be_lun->dev_path);
1912 		return (error);
1913 	}
1914 
1915 	dev = be_lun->vn->v_rdev;
1916 	devsw = dev->si_devsw;
1917 	if (!devsw->d_ioctl) {
1918 		snprintf(req->error_str, sizeof(req->error_str),
1919 			 "no d_ioctl for device %s!",
1920 			 be_lun->dev_path);
1921 		return (ENODEV);
1922 	}
1923 
1924 	error = devsw->d_ioctl(dev, DIOCGSECTORSIZE,
1925 			       (caddr_t)&be_lun->blocksize, FREAD,
1926 			       curthread);
1927 	if (error) {
1928 		snprintf(req->error_str, sizeof(req->error_str),
1929 			 "error %d returned for DIOCGSECTORSIZE ioctl "
1930 			 "on %s!", error, be_lun->dev_path);
1931 		return (error);
1932 	}
1933 
1934 	/*
1935 	 * If the user has asked for a blocksize that is greater than the
1936 	 * backing device's blocksize, we can do it only if the blocksize
1937 	 * the user is asking for is an even multiple of the underlying
1938 	 * device's blocksize.
1939 	 */
1940 	if ((params->blocksize_bytes != 0)
1941 	 && (params->blocksize_bytes > be_lun->blocksize)) {
1942 		uint32_t bs_multiple, tmp_blocksize;
1943 
1944 		bs_multiple = params->blocksize_bytes / be_lun->blocksize;
1945 
1946 		tmp_blocksize = bs_multiple * be_lun->blocksize;
1947 
1948 		if (tmp_blocksize == params->blocksize_bytes) {
1949 			be_lun->blocksize = params->blocksize_bytes;
1950 		} else {
1951 			snprintf(req->error_str, sizeof(req->error_str),
1952 				 "requested blocksize %u is not an even "
1953 				 "multiple of backing device blocksize %u",
1954 				 params->blocksize_bytes,
1955 				 be_lun->blocksize);
1956 			return (EINVAL);
1957 
1958 		}
1959 	} else if ((params->blocksize_bytes != 0)
1960 		&& (params->blocksize_bytes != be_lun->blocksize)) {
1961 		snprintf(req->error_str, sizeof(req->error_str),
1962 			 "requested blocksize %u < backing device "
1963 			 "blocksize %u", params->blocksize_bytes,
1964 			 be_lun->blocksize);
1965 		return (EINVAL);
1966 	}
1967 
1968 	error = devsw->d_ioctl(dev, DIOCGMEDIASIZE,
1969 			       (caddr_t)&be_lun->size_bytes, FREAD,
1970 			       curthread);
1971 	if (error) {
1972 		snprintf(req->error_str, sizeof(req->error_str),
1973 			 "error %d returned for DIOCGMEDIASIZE "
1974 			 " ioctl on %s!", error,
1975 			 be_lun->dev_path);
1976 		return (error);
1977 	}
1978 
1979 	if (params->lun_size_bytes != 0) {
1980 		if (params->lun_size_bytes > be_lun->size_bytes) {
1981 			snprintf(req->error_str, sizeof(req->error_str),
1982 				 "requested LUN size %ju > backing device "
1983 				 "size %ju",
1984 				 (uintmax_t)params->lun_size_bytes,
1985 				 (uintmax_t)be_lun->size_bytes);
1986 			return (EINVAL);
1987 		}
1988 
1989 		be_lun->size_bytes = params->lun_size_bytes;
1990 	}
1991 
1992 	error = devsw->d_ioctl(dev, DIOCGSTRIPESIZE,
1993 			       (caddr_t)&ps, FREAD, curthread);
1994 	if (error)
1995 		ps = po = 0;
1996 	else {
1997 		error = devsw->d_ioctl(dev, DIOCGSTRIPEOFFSET,
1998 				       (caddr_t)&po, FREAD, curthread);
1999 		if (error)
2000 			po = 0;
2001 	}
2002 	us = ps;
2003 	uo = po;
2004 
2005 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "pblocksize");
2006 	if (value != NULL)
2007 		ctl_expand_number(value, &ps);
2008 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "pblockoffset");
2009 	if (value != NULL)
2010 		ctl_expand_number(value, &po);
2011 	pss = ps / be_lun->blocksize;
2012 	pos = po / be_lun->blocksize;
2013 	if ((pss > 0) && (pss * be_lun->blocksize == ps) && (pss >= pos) &&
2014 	    ((pss & (pss - 1)) == 0) && (pos * be_lun->blocksize == po)) {
2015 		be_lun->pblockexp = fls(pss) - 1;
2016 		be_lun->pblockoff = (pss - pos) % pss;
2017 	}
2018 
2019 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "ublocksize");
2020 	if (value != NULL)
2021 		ctl_expand_number(value, &us);
2022 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "ublockoffset");
2023 	if (value != NULL)
2024 		ctl_expand_number(value, &uo);
2025 	uss = us / be_lun->blocksize;
2026 	uos = uo / be_lun->blocksize;
2027 	if ((uss > 0) && (uss * be_lun->blocksize == us) && (uss >= uos) &&
2028 	    ((uss & (uss - 1)) == 0) && (uos * be_lun->blocksize == uo)) {
2029 		be_lun->ublockexp = fls(uss) - 1;
2030 		be_lun->ublockoff = (uss - uos) % uss;
2031 	}
2032 
2033 	be_lun->atomicblock = atomic / be_lun->blocksize;
2034 	be_lun->opttxferlen = maxio / be_lun->blocksize;
2035 
2036 	if (be_lun->dispatch == ctl_be_block_dispatch_zvol) {
2037 		unmap = 1;
2038 	} else {
2039 		struct diocgattr_arg	arg;
2040 
2041 		strlcpy(arg.name, "GEOM::candelete", sizeof(arg.name));
2042 		arg.len = sizeof(arg.value.i);
2043 		error = devsw->d_ioctl(dev, DIOCGATTR,
2044 		    (caddr_t)&arg, FREAD, curthread);
2045 		unmap = (error == 0) ? arg.value.i : 0;
2046 	}
2047 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "unmap");
2048 	if (value != NULL)
2049 		unmap = (strcmp(value, "on") == 0);
2050 	if (unmap)
2051 		be_lun->unmap = ctl_be_block_unmap_dev;
2052 
2053 	return (0);
2054 }
2055 
2056 static int
2057 ctl_be_block_close(struct ctl_be_block_lun *be_lun)
2058 {
2059 	DROP_GIANT();
2060 	if (be_lun->vn) {
2061 		int flags = FREAD | FWRITE;
2062 
2063 		switch (be_lun->dev_type) {
2064 		case CTL_BE_BLOCK_DEV:
2065 			if (be_lun->backend.dev.csw) {
2066 				dev_relthread(be_lun->backend.dev.cdev,
2067 					      be_lun->backend.dev.dev_ref);
2068 				be_lun->backend.dev.csw  = NULL;
2069 				be_lun->backend.dev.cdev = NULL;
2070 			}
2071 			break;
2072 		case CTL_BE_BLOCK_FILE:
2073 			break;
2074 		case CTL_BE_BLOCK_NONE:
2075 			break;
2076 		default:
2077 			panic("Unexpected backend type.");
2078 			break;
2079 		}
2080 
2081 		(void)vn_close(be_lun->vn, flags, NOCRED, curthread);
2082 		be_lun->vn = NULL;
2083 
2084 		switch (be_lun->dev_type) {
2085 		case CTL_BE_BLOCK_DEV:
2086 			break;
2087 		case CTL_BE_BLOCK_FILE:
2088 			if (be_lun->backend.file.cred != NULL) {
2089 				crfree(be_lun->backend.file.cred);
2090 				be_lun->backend.file.cred = NULL;
2091 			}
2092 			break;
2093 		case CTL_BE_BLOCK_NONE:
2094 			break;
2095 		default:
2096 			panic("Unexpected backend type.");
2097 			break;
2098 		}
2099 		be_lun->dev_type = CTL_BE_BLOCK_NONE;
2100 	}
2101 	PICKUP_GIANT();
2102 
2103 	return (0);
2104 }
2105 
2106 static int
2107 ctl_be_block_open(struct ctl_be_block_softc *softc,
2108 		       struct ctl_be_block_lun *be_lun, struct ctl_lun_req *req)
2109 {
2110 	struct nameidata nd;
2111 	int		 flags;
2112 	int		 error;
2113 
2114 	/*
2115 	 * XXX KDM allow a read-only option?
2116 	 */
2117 	flags = FREAD | FWRITE;
2118 	error = 0;
2119 
2120 	if (rootvnode == NULL) {
2121 		snprintf(req->error_str, sizeof(req->error_str),
2122 			 "Root filesystem is not mounted");
2123 		return (1);
2124 	}
2125 
2126 	pwd_ensure_dirs();
2127 
2128  again:
2129 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, be_lun->dev_path, curthread);
2130 	error = vn_open(&nd, &flags, 0, NULL);
2131 	if (error) {
2132 		/*
2133 		 * This is the only reasonable guess we can make as far as
2134 		 * path if the user doesn't give us a fully qualified path.
2135 		 * If they want to specify a file, they need to specify the
2136 		 * full path.
2137 		 */
2138 		if (be_lun->dev_path[0] != '/') {
2139 			char *dev_path = "/dev/";
2140 			char *dev_name;
2141 
2142 			/* Try adding device path at beginning of name */
2143 			dev_name = malloc(strlen(be_lun->dev_path)
2144 					+ strlen(dev_path) + 1,
2145 					  M_CTLBLK, M_WAITOK);
2146 			if (dev_name) {
2147 				sprintf(dev_name, "%s%s", dev_path,
2148 					be_lun->dev_path);
2149 				free(be_lun->dev_path, M_CTLBLK);
2150 				be_lun->dev_path = dev_name;
2151 				goto again;
2152 			}
2153 		}
2154 		snprintf(req->error_str, sizeof(req->error_str),
2155 		    "error opening %s: %d", be_lun->dev_path, error);
2156 		return (error);
2157 	}
2158 
2159 	NDFREE(&nd, NDF_ONLY_PNBUF);
2160 
2161 	be_lun->vn = nd.ni_vp;
2162 
2163 	/* We only support disks and files. */
2164 	if (vn_isdisk(be_lun->vn, &error)) {
2165 		error = ctl_be_block_open_dev(be_lun, req);
2166 	} else if (be_lun->vn->v_type == VREG) {
2167 		error = ctl_be_block_open_file(be_lun, req);
2168 	} else {
2169 		error = EINVAL;
2170 		snprintf(req->error_str, sizeof(req->error_str),
2171 			 "%s is not a disk or plain file", be_lun->dev_path);
2172 	}
2173 	VOP_UNLOCK(be_lun->vn, 0);
2174 
2175 	if (error != 0) {
2176 		ctl_be_block_close(be_lun);
2177 		return (error);
2178 	}
2179 
2180 	be_lun->blocksize_shift = fls(be_lun->blocksize) - 1;
2181 	be_lun->size_blocks = be_lun->size_bytes >> be_lun->blocksize_shift;
2182 
2183 	return (0);
2184 }
2185 
2186 static int
2187 ctl_be_block_create(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2188 {
2189 	struct ctl_be_block_lun *be_lun;
2190 	struct ctl_lun_create_params *params;
2191 	char num_thread_str[16];
2192 	char tmpstr[32];
2193 	char *value;
2194 	int retval, num_threads;
2195 	int tmp_num_threads;
2196 
2197 	params = &req->reqdata.create;
2198 	retval = 0;
2199 	req->status = CTL_LUN_OK;
2200 
2201 	num_threads = cbb_num_threads;
2202 
2203 	be_lun = malloc(sizeof(*be_lun), M_CTLBLK, M_ZERO | M_WAITOK);
2204 
2205 	be_lun->params = req->reqdata.create;
2206 	be_lun->softc = softc;
2207 	STAILQ_INIT(&be_lun->input_queue);
2208 	STAILQ_INIT(&be_lun->config_read_queue);
2209 	STAILQ_INIT(&be_lun->config_write_queue);
2210 	STAILQ_INIT(&be_lun->datamove_queue);
2211 	sprintf(be_lun->lunname, "cblk%d", softc->num_luns);
2212 	mtx_init(&be_lun->io_lock, "cblk io lock", NULL, MTX_DEF);
2213 	mtx_init(&be_lun->queue_lock, "cblk queue lock", NULL, MTX_DEF);
2214 	ctl_init_opts(&be_lun->ctl_be_lun.options,
2215 	    req->num_be_args, req->kern_be_args);
2216 
2217 	be_lun->lun_zone = uma_zcreate(be_lun->lunname, CTLBLK_MAX_SEG,
2218 	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
2219 
2220 	if (be_lun->lun_zone == NULL) {
2221 		snprintf(req->error_str, sizeof(req->error_str),
2222 			 "error allocating UMA zone");
2223 		goto bailout_error;
2224 	}
2225 
2226 	if (params->flags & CTL_LUN_FLAG_DEV_TYPE)
2227 		be_lun->ctl_be_lun.lun_type = params->device_type;
2228 	else
2229 		be_lun->ctl_be_lun.lun_type = T_DIRECT;
2230 
2231 	if (be_lun->ctl_be_lun.lun_type == T_DIRECT) {
2232 		value = ctl_get_opt(&be_lun->ctl_be_lun.options, "file");
2233 		if (value == NULL) {
2234 			snprintf(req->error_str, sizeof(req->error_str),
2235 				 "no file argument specified");
2236 			goto bailout_error;
2237 		}
2238 		be_lun->dev_path = strdup(value, M_CTLBLK);
2239 		be_lun->blocksize = 512;
2240 		be_lun->blocksize_shift = fls(be_lun->blocksize) - 1;
2241 
2242 		retval = ctl_be_block_open(softc, be_lun, req);
2243 		if (retval != 0) {
2244 			retval = 0;
2245 			req->status = CTL_LUN_WARNING;
2246 		}
2247 	} else {
2248 		/*
2249 		 * For processor devices, we don't have any size.
2250 		 */
2251 		be_lun->blocksize = 0;
2252 		be_lun->pblockexp = 0;
2253 		be_lun->pblockoff = 0;
2254 		be_lun->ublockexp = 0;
2255 		be_lun->ublockoff = 0;
2256 		be_lun->size_blocks = 0;
2257 		be_lun->size_bytes = 0;
2258 		be_lun->ctl_be_lun.maxlba = 0;
2259 
2260 		/*
2261 		 * Default to just 1 thread for processor devices.
2262 		 */
2263 		num_threads = 1;
2264 	}
2265 
2266 	/*
2267 	 * XXX This searching loop might be refactored to be combined with
2268 	 * the loop above,
2269 	 */
2270 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "num_threads");
2271 	if (value != NULL) {
2272 		tmp_num_threads = strtol(value, NULL, 0);
2273 
2274 		/*
2275 		 * We don't let the user specify less than one
2276 		 * thread, but hope he's clueful enough not to
2277 		 * specify 1000 threads.
2278 		 */
2279 		if (tmp_num_threads < 1) {
2280 			snprintf(req->error_str, sizeof(req->error_str),
2281 				 "invalid number of threads %s",
2282 				 num_thread_str);
2283 			goto bailout_error;
2284 		}
2285 		num_threads = tmp_num_threads;
2286 	}
2287 
2288 	be_lun->flags = CTL_BE_BLOCK_LUN_UNCONFIGURED;
2289 	be_lun->ctl_be_lun.flags = CTL_LUN_FLAG_PRIMARY;
2290 	if (be_lun->vn == NULL)
2291 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_OFFLINE;
2292 	if (be_lun->unmap != NULL)
2293 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_UNMAP;
2294 	if (be_lun->dispatch != ctl_be_block_dispatch_dev)
2295 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_SERSEQ_READ;
2296 	be_lun->ctl_be_lun.be_lun = be_lun;
2297 	be_lun->ctl_be_lun.maxlba = (be_lun->size_blocks == 0) ?
2298 	    0 : (be_lun->size_blocks - 1);
2299 	be_lun->ctl_be_lun.blocksize = be_lun->blocksize;
2300 	be_lun->ctl_be_lun.pblockexp = be_lun->pblockexp;
2301 	be_lun->ctl_be_lun.pblockoff = be_lun->pblockoff;
2302 	be_lun->ctl_be_lun.ublockexp = be_lun->ublockexp;
2303 	be_lun->ctl_be_lun.ublockoff = be_lun->ublockoff;
2304 	be_lun->ctl_be_lun.atomicblock = be_lun->atomicblock;
2305 	be_lun->ctl_be_lun.opttxferlen = be_lun->opttxferlen;
2306 	/* Tell the user the blocksize we ended up using */
2307 	params->lun_size_bytes = be_lun->size_bytes;
2308 	params->blocksize_bytes = be_lun->blocksize;
2309 	if (params->flags & CTL_LUN_FLAG_ID_REQ) {
2310 		be_lun->ctl_be_lun.req_lun_id = params->req_lun_id;
2311 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_ID_REQ;
2312 	} else
2313 		be_lun->ctl_be_lun.req_lun_id = 0;
2314 
2315 	be_lun->ctl_be_lun.lun_shutdown = ctl_be_block_lun_shutdown;
2316 	be_lun->ctl_be_lun.lun_config_status =
2317 		ctl_be_block_lun_config_status;
2318 	be_lun->ctl_be_lun.be = &ctl_be_block_driver;
2319 
2320 	if ((params->flags & CTL_LUN_FLAG_SERIAL_NUM) == 0) {
2321 		snprintf(tmpstr, sizeof(tmpstr), "MYSERIAL%4d",
2322 			 softc->num_luns);
2323 		strncpy((char *)be_lun->ctl_be_lun.serial_num, tmpstr,
2324 			MIN(sizeof(be_lun->ctl_be_lun.serial_num),
2325 			sizeof(tmpstr)));
2326 
2327 		/* Tell the user what we used for a serial number */
2328 		strncpy((char *)params->serial_num, tmpstr,
2329 			MIN(sizeof(params->serial_num), sizeof(tmpstr)));
2330 	} else {
2331 		strncpy((char *)be_lun->ctl_be_lun.serial_num,
2332 			params->serial_num,
2333 			MIN(sizeof(be_lun->ctl_be_lun.serial_num),
2334 			sizeof(params->serial_num)));
2335 	}
2336 	if ((params->flags & CTL_LUN_FLAG_DEVID) == 0) {
2337 		snprintf(tmpstr, sizeof(tmpstr), "MYDEVID%4d", softc->num_luns);
2338 		strncpy((char *)be_lun->ctl_be_lun.device_id, tmpstr,
2339 			MIN(sizeof(be_lun->ctl_be_lun.device_id),
2340 			sizeof(tmpstr)));
2341 
2342 		/* Tell the user what we used for a device ID */
2343 		strncpy((char *)params->device_id, tmpstr,
2344 			MIN(sizeof(params->device_id), sizeof(tmpstr)));
2345 	} else {
2346 		strncpy((char *)be_lun->ctl_be_lun.device_id,
2347 			params->device_id,
2348 			MIN(sizeof(be_lun->ctl_be_lun.device_id),
2349 			    sizeof(params->device_id)));
2350 	}
2351 
2352 	TASK_INIT(&be_lun->io_task, /*priority*/0, ctl_be_block_worker, be_lun);
2353 
2354 	be_lun->io_taskqueue = taskqueue_create(be_lun->lunname, M_WAITOK,
2355 	    taskqueue_thread_enqueue, /*context*/&be_lun->io_taskqueue);
2356 
2357 	if (be_lun->io_taskqueue == NULL) {
2358 		snprintf(req->error_str, sizeof(req->error_str),
2359 			 "unable to create taskqueue");
2360 		goto bailout_error;
2361 	}
2362 
2363 	/*
2364 	 * Note that we start the same number of threads by default for
2365 	 * both the file case and the block device case.  For the file
2366 	 * case, we need multiple threads to allow concurrency, because the
2367 	 * vnode interface is designed to be a blocking interface.  For the
2368 	 * block device case, ZFS zvols at least will block the caller's
2369 	 * context in many instances, and so we need multiple threads to
2370 	 * overcome that problem.  Other block devices don't need as many
2371 	 * threads, but they shouldn't cause too many problems.
2372 	 *
2373 	 * If the user wants to just have a single thread for a block
2374 	 * device, he can specify that when the LUN is created, or change
2375 	 * the tunable/sysctl to alter the default number of threads.
2376 	 */
2377 	retval = taskqueue_start_threads(&be_lun->io_taskqueue,
2378 					 /*num threads*/num_threads,
2379 					 /*priority*/PWAIT,
2380 					 /*thread name*/
2381 					 "%s taskq", be_lun->lunname);
2382 
2383 	if (retval != 0)
2384 		goto bailout_error;
2385 
2386 	be_lun->num_threads = num_threads;
2387 
2388 	mtx_lock(&softc->lock);
2389 	softc->num_luns++;
2390 	STAILQ_INSERT_TAIL(&softc->lun_list, be_lun, links);
2391 
2392 	mtx_unlock(&softc->lock);
2393 
2394 	retval = ctl_add_lun(&be_lun->ctl_be_lun);
2395 	if (retval != 0) {
2396 		mtx_lock(&softc->lock);
2397 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_block_lun,
2398 			      links);
2399 		softc->num_luns--;
2400 		mtx_unlock(&softc->lock);
2401 		snprintf(req->error_str, sizeof(req->error_str),
2402 			 "ctl_add_lun() returned error %d, see dmesg for "
2403 			 "details", retval);
2404 		retval = 0;
2405 		goto bailout_error;
2406 	}
2407 
2408 	mtx_lock(&softc->lock);
2409 
2410 	/*
2411 	 * Tell the config_status routine that we're waiting so it won't
2412 	 * clean up the LUN in the event of an error.
2413 	 */
2414 	be_lun->flags |= CTL_BE_BLOCK_LUN_WAITING;
2415 
2416 	while (be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) {
2417 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlblk", 0);
2418 		if (retval == EINTR)
2419 			break;
2420 	}
2421 	be_lun->flags &= ~CTL_BE_BLOCK_LUN_WAITING;
2422 
2423 	if (be_lun->flags & CTL_BE_BLOCK_LUN_CONFIG_ERR) {
2424 		snprintf(req->error_str, sizeof(req->error_str),
2425 			 "LUN configuration error, see dmesg for details");
2426 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_block_lun,
2427 			      links);
2428 		softc->num_luns--;
2429 		mtx_unlock(&softc->lock);
2430 		goto bailout_error;
2431 	} else {
2432 		params->req_lun_id = be_lun->ctl_be_lun.lun_id;
2433 	}
2434 
2435 	mtx_unlock(&softc->lock);
2436 
2437 	be_lun->disk_stats = devstat_new_entry("cbb", params->req_lun_id,
2438 					       be_lun->blocksize,
2439 					       DEVSTAT_ALL_SUPPORTED,
2440 					       be_lun->ctl_be_lun.lun_type
2441 					       | DEVSTAT_TYPE_IF_OTHER,
2442 					       DEVSTAT_PRIORITY_OTHER);
2443 
2444 	return (retval);
2445 
2446 bailout_error:
2447 	req->status = CTL_LUN_ERROR;
2448 
2449 	if (be_lun->io_taskqueue != NULL)
2450 		taskqueue_free(be_lun->io_taskqueue);
2451 	ctl_be_block_close(be_lun);
2452 	if (be_lun->dev_path != NULL)
2453 		free(be_lun->dev_path, M_CTLBLK);
2454 	if (be_lun->lun_zone != NULL)
2455 		uma_zdestroy(be_lun->lun_zone);
2456 	ctl_free_opts(&be_lun->ctl_be_lun.options);
2457 	mtx_destroy(&be_lun->queue_lock);
2458 	mtx_destroy(&be_lun->io_lock);
2459 	free(be_lun, M_CTLBLK);
2460 
2461 	return (retval);
2462 }
2463 
2464 static int
2465 ctl_be_block_rm(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2466 {
2467 	struct ctl_lun_rm_params *params;
2468 	struct ctl_be_block_lun *be_lun;
2469 	int retval;
2470 
2471 	params = &req->reqdata.rm;
2472 
2473 	mtx_lock(&softc->lock);
2474 
2475 	be_lun = NULL;
2476 
2477 	STAILQ_FOREACH(be_lun, &softc->lun_list, links) {
2478 		if (be_lun->ctl_be_lun.lun_id == params->lun_id)
2479 			break;
2480 	}
2481 	mtx_unlock(&softc->lock);
2482 
2483 	if (be_lun == NULL) {
2484 		snprintf(req->error_str, sizeof(req->error_str),
2485 			 "LUN %u is not managed by the block backend",
2486 			 params->lun_id);
2487 		goto bailout_error;
2488 	}
2489 
2490 	retval = ctl_disable_lun(&be_lun->ctl_be_lun);
2491 
2492 	if (retval != 0) {
2493 		snprintf(req->error_str, sizeof(req->error_str),
2494 			 "error %d returned from ctl_disable_lun() for "
2495 			 "LUN %d", retval, params->lun_id);
2496 		goto bailout_error;
2497 
2498 	}
2499 
2500 	retval = ctl_invalidate_lun(&be_lun->ctl_be_lun);
2501 	if (retval != 0) {
2502 		snprintf(req->error_str, sizeof(req->error_str),
2503 			 "error %d returned from ctl_invalidate_lun() for "
2504 			 "LUN %d", retval, params->lun_id);
2505 		goto bailout_error;
2506 	}
2507 
2508 	mtx_lock(&softc->lock);
2509 
2510 	be_lun->flags |= CTL_BE_BLOCK_LUN_WAITING;
2511 
2512 	while ((be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) == 0) {
2513                 retval = msleep(be_lun, &softc->lock, PCATCH, "ctlblk", 0);
2514                 if (retval == EINTR)
2515                         break;
2516         }
2517 
2518 	be_lun->flags &= ~CTL_BE_BLOCK_LUN_WAITING;
2519 
2520 	if ((be_lun->flags & CTL_BE_BLOCK_LUN_UNCONFIGURED) == 0) {
2521 		snprintf(req->error_str, sizeof(req->error_str),
2522 			 "interrupted waiting for LUN to be freed");
2523 		mtx_unlock(&softc->lock);
2524 		goto bailout_error;
2525 	}
2526 
2527 	STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_block_lun, links);
2528 
2529 	softc->num_luns--;
2530 	mtx_unlock(&softc->lock);
2531 
2532 	taskqueue_drain(be_lun->io_taskqueue, &be_lun->io_task);
2533 
2534 	taskqueue_free(be_lun->io_taskqueue);
2535 
2536 	ctl_be_block_close(be_lun);
2537 
2538 	if (be_lun->disk_stats != NULL)
2539 		devstat_remove_entry(be_lun->disk_stats);
2540 
2541 	uma_zdestroy(be_lun->lun_zone);
2542 
2543 	ctl_free_opts(&be_lun->ctl_be_lun.options);
2544 	free(be_lun->dev_path, M_CTLBLK);
2545 	mtx_destroy(&be_lun->queue_lock);
2546 	mtx_destroy(&be_lun->io_lock);
2547 	free(be_lun, M_CTLBLK);
2548 
2549 	req->status = CTL_LUN_OK;
2550 
2551 	return (0);
2552 
2553 bailout_error:
2554 
2555 	req->status = CTL_LUN_ERROR;
2556 
2557 	return (0);
2558 }
2559 
2560 static int
2561 ctl_be_block_modify_file(struct ctl_be_block_lun *be_lun,
2562 			 struct ctl_lun_req *req)
2563 {
2564 	struct vattr vattr;
2565 	int error;
2566 	struct ctl_lun_create_params *params = &be_lun->params;
2567 
2568 	if (params->lun_size_bytes != 0) {
2569 		be_lun->size_bytes = params->lun_size_bytes;
2570 	} else  {
2571 		vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
2572 		error = VOP_GETATTR(be_lun->vn, &vattr, curthread->td_ucred);
2573 		VOP_UNLOCK(be_lun->vn, 0);
2574 		if (error != 0) {
2575 			snprintf(req->error_str, sizeof(req->error_str),
2576 				 "error calling VOP_GETATTR() for file %s",
2577 				 be_lun->dev_path);
2578 			return (error);
2579 		}
2580 
2581 		be_lun->size_bytes = vattr.va_size;
2582 	}
2583 
2584 	return (0);
2585 }
2586 
2587 static int
2588 ctl_be_block_modify_dev(struct ctl_be_block_lun *be_lun,
2589 			struct ctl_lun_req *req)
2590 {
2591 	struct ctl_be_block_devdata *dev_data;
2592 	int error;
2593 	struct ctl_lun_create_params *params = &be_lun->params;
2594 	uint64_t size_bytes;
2595 
2596 	dev_data = &be_lun->backend.dev;
2597 	if (!dev_data->csw->d_ioctl) {
2598 		snprintf(req->error_str, sizeof(req->error_str),
2599 			 "no d_ioctl for device %s!", be_lun->dev_path);
2600 		return (ENODEV);
2601 	}
2602 
2603 	error = dev_data->csw->d_ioctl(dev_data->cdev, DIOCGMEDIASIZE,
2604 			       (caddr_t)&size_bytes, FREAD,
2605 			       curthread);
2606 	if (error) {
2607 		snprintf(req->error_str, sizeof(req->error_str),
2608 			 "error %d returned for DIOCGMEDIASIZE ioctl "
2609 			 "on %s!", error, be_lun->dev_path);
2610 		return (error);
2611 	}
2612 
2613 	if (params->lun_size_bytes != 0) {
2614 		if (params->lun_size_bytes > size_bytes) {
2615 			snprintf(req->error_str, sizeof(req->error_str),
2616 				 "requested LUN size %ju > backing device "
2617 				 "size %ju",
2618 				 (uintmax_t)params->lun_size_bytes,
2619 				 (uintmax_t)size_bytes);
2620 			return (EINVAL);
2621 		}
2622 
2623 		be_lun->size_bytes = params->lun_size_bytes;
2624 	} else {
2625 		be_lun->size_bytes = size_bytes;
2626 	}
2627 
2628 	return (0);
2629 }
2630 
2631 static int
2632 ctl_be_block_modify(struct ctl_be_block_softc *softc, struct ctl_lun_req *req)
2633 {
2634 	struct ctl_lun_modify_params *params;
2635 	struct ctl_be_block_lun *be_lun;
2636 	uint64_t oldsize;
2637 	int error;
2638 
2639 	params = &req->reqdata.modify;
2640 
2641 	mtx_lock(&softc->lock);
2642 	be_lun = NULL;
2643 	STAILQ_FOREACH(be_lun, &softc->lun_list, links) {
2644 		if (be_lun->ctl_be_lun.lun_id == params->lun_id)
2645 			break;
2646 	}
2647 	mtx_unlock(&softc->lock);
2648 
2649 	if (be_lun == NULL) {
2650 		snprintf(req->error_str, sizeof(req->error_str),
2651 			 "LUN %u is not managed by the block backend",
2652 			 params->lun_id);
2653 		goto bailout_error;
2654 	}
2655 
2656 	be_lun->params.lun_size_bytes = params->lun_size_bytes;
2657 
2658 	oldsize = be_lun->size_bytes;
2659 	if (be_lun->vn == NULL)
2660 		error = ctl_be_block_open(softc, be_lun, req);
2661 	else if (vn_isdisk(be_lun->vn, &error))
2662 		error = ctl_be_block_modify_dev(be_lun, req);
2663 	else if (be_lun->vn->v_type == VREG)
2664 		error = ctl_be_block_modify_file(be_lun, req);
2665 	else
2666 		error = EINVAL;
2667 
2668 	if (error == 0 && be_lun->size_bytes != oldsize) {
2669 		be_lun->size_blocks = be_lun->size_bytes >>
2670 		    be_lun->blocksize_shift;
2671 
2672 		/*
2673 		 * The maximum LBA is the size - 1.
2674 		 *
2675 		 * XXX: Note that this field is being updated without locking,
2676 		 * 	which might cause problems on 32-bit architectures.
2677 		 */
2678 		if (be_lun->unmap != NULL)
2679 			be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_UNMAP;
2680 		be_lun->ctl_be_lun.maxlba = (be_lun->size_blocks == 0) ?
2681 		    0 : (be_lun->size_blocks - 1);
2682 		be_lun->ctl_be_lun.blocksize = be_lun->blocksize;
2683 		be_lun->ctl_be_lun.pblockexp = be_lun->pblockexp;
2684 		be_lun->ctl_be_lun.pblockoff = be_lun->pblockoff;
2685 		be_lun->ctl_be_lun.ublockexp = be_lun->ublockexp;
2686 		be_lun->ctl_be_lun.ublockoff = be_lun->ublockoff;
2687 		be_lun->ctl_be_lun.atomicblock = be_lun->atomicblock;
2688 		be_lun->ctl_be_lun.opttxferlen = be_lun->opttxferlen;
2689 		ctl_lun_capacity_changed(&be_lun->ctl_be_lun);
2690 		if (oldsize == 0 && be_lun->size_blocks != 0)
2691 			ctl_lun_online(&be_lun->ctl_be_lun);
2692 	}
2693 
2694 	/* Tell the user the exact size we ended up using */
2695 	params->lun_size_bytes = be_lun->size_bytes;
2696 
2697 	req->status = error ? CTL_LUN_WARNING : CTL_LUN_OK;
2698 
2699 	return (0);
2700 
2701 bailout_error:
2702 	req->status = CTL_LUN_ERROR;
2703 
2704 	return (0);
2705 }
2706 
2707 static void
2708 ctl_be_block_lun_shutdown(void *be_lun)
2709 {
2710 	struct ctl_be_block_lun *lun;
2711 	struct ctl_be_block_softc *softc;
2712 
2713 	lun = (struct ctl_be_block_lun *)be_lun;
2714 
2715 	softc = lun->softc;
2716 
2717 	mtx_lock(&softc->lock);
2718 	lun->flags |= CTL_BE_BLOCK_LUN_UNCONFIGURED;
2719 	if (lun->flags & CTL_BE_BLOCK_LUN_WAITING)
2720 		wakeup(lun);
2721 	mtx_unlock(&softc->lock);
2722 
2723 }
2724 
2725 static void
2726 ctl_be_block_lun_config_status(void *be_lun, ctl_lun_config_status status)
2727 {
2728 	struct ctl_be_block_lun *lun;
2729 	struct ctl_be_block_softc *softc;
2730 
2731 	lun = (struct ctl_be_block_lun *)be_lun;
2732 	softc = lun->softc;
2733 
2734 	if (status == CTL_LUN_CONFIG_OK) {
2735 		mtx_lock(&softc->lock);
2736 		lun->flags &= ~CTL_BE_BLOCK_LUN_UNCONFIGURED;
2737 		if (lun->flags & CTL_BE_BLOCK_LUN_WAITING)
2738 			wakeup(lun);
2739 		mtx_unlock(&softc->lock);
2740 
2741 		/*
2742 		 * We successfully added the LUN, attempt to enable it.
2743 		 */
2744 		if (ctl_enable_lun(&lun->ctl_be_lun) != 0) {
2745 			printf("%s: ctl_enable_lun() failed!\n", __func__);
2746 			if (ctl_invalidate_lun(&lun->ctl_be_lun) != 0) {
2747 				printf("%s: ctl_invalidate_lun() failed!\n",
2748 				       __func__);
2749 			}
2750 		}
2751 
2752 		return;
2753 	}
2754 
2755 
2756 	mtx_lock(&softc->lock);
2757 	lun->flags &= ~CTL_BE_BLOCK_LUN_UNCONFIGURED;
2758 	lun->flags |= CTL_BE_BLOCK_LUN_CONFIG_ERR;
2759 	wakeup(lun);
2760 	mtx_unlock(&softc->lock);
2761 }
2762 
2763 
2764 static int
2765 ctl_be_block_config_write(union ctl_io *io)
2766 {
2767 	struct ctl_be_block_lun *be_lun;
2768 	struct ctl_be_lun *ctl_be_lun;
2769 	int retval;
2770 
2771 	retval = 0;
2772 
2773 	DPRINTF("entered\n");
2774 
2775 	ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
2776 		CTL_PRIV_BACKEND_LUN].ptr;
2777 	be_lun = (struct ctl_be_block_lun *)ctl_be_lun->be_lun;
2778 
2779 	switch (io->scsiio.cdb[0]) {
2780 	case SYNCHRONIZE_CACHE:
2781 	case SYNCHRONIZE_CACHE_16:
2782 	case WRITE_SAME_10:
2783 	case WRITE_SAME_16:
2784 	case UNMAP:
2785 		/*
2786 		 * The upper level CTL code will filter out any CDBs with
2787 		 * the immediate bit set and return the proper error.
2788 		 *
2789 		 * We don't really need to worry about what LBA range the
2790 		 * user asked to be synced out.  When they issue a sync
2791 		 * cache command, we'll sync out the whole thing.
2792 		 */
2793 		mtx_lock(&be_lun->queue_lock);
2794 		STAILQ_INSERT_TAIL(&be_lun->config_write_queue, &io->io_hdr,
2795 				   links);
2796 		mtx_unlock(&be_lun->queue_lock);
2797 		taskqueue_enqueue(be_lun->io_taskqueue, &be_lun->io_task);
2798 		break;
2799 	case START_STOP_UNIT: {
2800 		struct scsi_start_stop_unit *cdb;
2801 
2802 		cdb = (struct scsi_start_stop_unit *)io->scsiio.cdb;
2803 
2804 		if (cdb->how & SSS_START)
2805 			retval = ctl_start_lun(ctl_be_lun);
2806 		else {
2807 			retval = ctl_stop_lun(ctl_be_lun);
2808 			/*
2809 			 * XXX KDM Copan-specific offline behavior.
2810 			 * Figure out a reasonable way to port this?
2811 			 */
2812 #ifdef NEEDTOPORT
2813 			if ((retval == 0)
2814 			 && (cdb->byte2 & SSS_ONOFFLINE))
2815 				retval = ctl_lun_offline(ctl_be_lun);
2816 #endif
2817 		}
2818 
2819 		/*
2820 		 * In general, the above routines should not fail.  They
2821 		 * just set state for the LUN.  So we've got something
2822 		 * pretty wrong here if we can't start or stop the LUN.
2823 		 */
2824 		if (retval != 0) {
2825 			ctl_set_internal_failure(&io->scsiio,
2826 						 /*sks_valid*/ 1,
2827 						 /*retry_count*/ 0xf051);
2828 			retval = CTL_RETVAL_COMPLETE;
2829 		} else {
2830 			ctl_set_success(&io->scsiio);
2831 		}
2832 		ctl_config_write_done(io);
2833 		break;
2834 	}
2835 	default:
2836 		ctl_set_invalid_opcode(&io->scsiio);
2837 		ctl_config_write_done(io);
2838 		retval = CTL_RETVAL_COMPLETE;
2839 		break;
2840 	}
2841 
2842 	return (retval);
2843 }
2844 
2845 static int
2846 ctl_be_block_config_read(union ctl_io *io)
2847 {
2848 	struct ctl_be_block_lun *be_lun;
2849 	struct ctl_be_lun *ctl_be_lun;
2850 	int retval = 0;
2851 
2852 	DPRINTF("entered\n");
2853 
2854 	ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
2855 		CTL_PRIV_BACKEND_LUN].ptr;
2856 	be_lun = (struct ctl_be_block_lun *)ctl_be_lun->be_lun;
2857 
2858 	switch (io->scsiio.cdb[0]) {
2859 	case SERVICE_ACTION_IN:
2860 		if (io->scsiio.cdb[1] == SGLS_SERVICE_ACTION) {
2861 			mtx_lock(&be_lun->queue_lock);
2862 			STAILQ_INSERT_TAIL(&be_lun->config_read_queue,
2863 			    &io->io_hdr, links);
2864 			mtx_unlock(&be_lun->queue_lock);
2865 			taskqueue_enqueue(be_lun->io_taskqueue,
2866 			    &be_lun->io_task);
2867 			retval = CTL_RETVAL_QUEUED;
2868 			break;
2869 		}
2870 		ctl_set_invalid_field(&io->scsiio,
2871 				      /*sks_valid*/ 1,
2872 				      /*command*/ 1,
2873 				      /*field*/ 1,
2874 				      /*bit_valid*/ 1,
2875 				      /*bit*/ 4);
2876 		ctl_config_read_done(io);
2877 		retval = CTL_RETVAL_COMPLETE;
2878 		break;
2879 	default:
2880 		ctl_set_invalid_opcode(&io->scsiio);
2881 		ctl_config_read_done(io);
2882 		retval = CTL_RETVAL_COMPLETE;
2883 		break;
2884 	}
2885 
2886 	return (retval);
2887 }
2888 
2889 static int
2890 ctl_be_block_lun_info(void *be_lun, struct sbuf *sb)
2891 {
2892 	struct ctl_be_block_lun *lun;
2893 	int retval;
2894 
2895 	lun = (struct ctl_be_block_lun *)be_lun;
2896 	retval = 0;
2897 
2898 	retval = sbuf_printf(sb, "\t<num_threads>");
2899 
2900 	if (retval != 0)
2901 		goto bailout;
2902 
2903 	retval = sbuf_printf(sb, "%d", lun->num_threads);
2904 
2905 	if (retval != 0)
2906 		goto bailout;
2907 
2908 	retval = sbuf_printf(sb, "</num_threads>\n");
2909 
2910 bailout:
2911 
2912 	return (retval);
2913 }
2914 
2915 static uint64_t
2916 ctl_be_block_lun_attr(void *be_lun, const char *attrname)
2917 {
2918 	struct ctl_be_block_lun *lun = (struct ctl_be_block_lun *)be_lun;
2919 
2920 	if (lun->getattr == NULL)
2921 		return (UINT64_MAX);
2922 	return (lun->getattr(lun, attrname));
2923 }
2924 
2925 int
2926 ctl_be_block_init(void)
2927 {
2928 	struct ctl_be_block_softc *softc;
2929 	int retval;
2930 
2931 	softc = &backend_block_softc;
2932 	retval = 0;
2933 
2934 	mtx_init(&softc->lock, "ctlblock", NULL, MTX_DEF);
2935 	beio_zone = uma_zcreate("beio", sizeof(struct ctl_be_block_io),
2936 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
2937 	STAILQ_INIT(&softc->disk_list);
2938 	STAILQ_INIT(&softc->lun_list);
2939 
2940 	return (retval);
2941 }
2942