xref: /dragonfly/sys/kern/subr_diskiocom.c (revision ef3ac1d1)
1 /*
2  * Copyright (c) 2012 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/proc.h>
38 #include <sys/sysctl.h>
39 #include <sys/buf.h>
40 #include <sys/conf.h>
41 #include <sys/disklabel.h>
42 #include <sys/disklabel32.h>
43 #include <sys/disklabel64.h>
44 #include <sys/diskslice.h>
45 #include <sys/diskmbr.h>
46 #include <sys/disk.h>
47 #include <sys/malloc.h>
48 #include <sys/device.h>
49 #include <sys/devfs.h>
50 #include <sys/thread.h>
51 #include <sys/queue.h>
52 #include <sys/lock.h>
53 #include <sys/stat.h>
54 #include <sys/uuid.h>
55 #include <sys/dmsg.h>
56 
57 #include <sys/buf2.h>
58 #include <sys/mplock2.h>
59 #include <sys/msgport2.h>
60 #include <sys/thread2.h>
61 
62 struct dios_open {
63 	int	openrd;
64 	int	openwr;
65 };
66 
67 struct dios_io {
68 	int	count;
69 	int	eof;
70 };
71 
72 static MALLOC_DEFINE(M_DMSG_DISK, "dmsg_disk", "disk dmsg");
73 
74 static int disk_iocom_reconnect(struct disk *dp, struct file *fp);
75 static int disk_rcvdmsg(kdmsg_msg_t *msg);
76 
77 static void disk_blk_open(struct disk *dp, kdmsg_msg_t *msg);
78 static void disk_blk_read(struct disk *dp, kdmsg_msg_t *msg);
79 static void disk_blk_write(struct disk *dp, kdmsg_msg_t *msg);
80 static void disk_blk_flush(struct disk *dp, kdmsg_msg_t *msg);
81 static void disk_blk_freeblks(struct disk *dp, kdmsg_msg_t *msg);
82 static void diskiodone(struct bio *bio);
83 
84 void
85 disk_iocom_init(struct disk *dp)
86 {
87 	kdmsg_iocom_init(&dp->d_iocom, dp,
88 			 KDMSG_IOCOMF_AUTOCONN |
89 			 KDMSG_IOCOMF_AUTORXSPAN |
90 			 KDMSG_IOCOMF_AUTOTXSPAN,
91 			 M_DMSG_DISK, disk_rcvdmsg);
92 }
93 
94 void
95 disk_iocom_update(struct disk *dp)
96 {
97 }
98 
99 void
100 disk_iocom_uninit(struct disk *dp)
101 {
102 	kdmsg_iocom_uninit(&dp->d_iocom);
103 }
104 
105 int
106 disk_iocom_ioctl(struct disk *dp, int cmd, void *data)
107 {
108 	struct file *fp;
109 	struct disk_ioc_recluster *recl;
110 	int error;
111 
112 	switch(cmd) {
113 	case DIOCRECLUSTER:
114 		recl = data;
115 		fp = holdfp(curproc->p_fd, recl->fd, -1);
116 		if (fp) {
117 			error = disk_iocom_reconnect(dp, fp);
118 		} else {
119 			error = EINVAL;
120 		}
121 		break;
122 	default:
123 		error = EOPNOTSUPP;
124 		break;
125 	}
126 	return error;
127 }
128 
129 static
130 int
131 disk_iocom_reconnect(struct disk *dp, struct file *fp)
132 {
133 	char devname[64];
134 
135 	ksnprintf(devname, sizeof(devname), "%s%d",
136 		  dev_dname(dp->d_rawdev), dkunit(dp->d_rawdev));
137 
138 	kdmsg_iocom_reconnect(&dp->d_iocom, fp, devname);
139 
140 	dp->d_iocom.auto_lnk_conn.pfs_type = DMSG_PFSTYPE_SERVER;
141 	dp->d_iocom.auto_lnk_conn.proto_version = DMSG_SPAN_PROTO_1;
142 	dp->d_iocom.auto_lnk_conn.peer_type = DMSG_PEER_BLOCK;
143 	dp->d_iocom.auto_lnk_conn.peer_mask = 1LLU << DMSG_PEER_BLOCK;
144 	dp->d_iocom.auto_lnk_conn.pfs_mask = (uint64_t)-1;
145 	ksnprintf(dp->d_iocom.auto_lnk_conn.cl_label,
146 		  sizeof(dp->d_iocom.auto_lnk_conn.cl_label),
147 		  "%s/%s", hostname, devname);
148 	if (dp->d_info.d_serialno) {
149 		ksnprintf(dp->d_iocom.auto_lnk_conn.fs_label,
150 			  sizeof(dp->d_iocom.auto_lnk_conn.fs_label),
151 			  "%s", dp->d_info.d_serialno);
152 	}
153 
154 	dp->d_iocom.auto_lnk_span.pfs_type = DMSG_PFSTYPE_SERVER;
155 	dp->d_iocom.auto_lnk_span.proto_version = DMSG_SPAN_PROTO_1;
156 	dp->d_iocom.auto_lnk_span.peer_type = DMSG_PEER_BLOCK;
157 	dp->d_iocom.auto_lnk_span.media.block.bytes =
158 						dp->d_info.d_media_size;
159 	dp->d_iocom.auto_lnk_span.media.block.blksize =
160 						dp->d_info.d_media_blksize;
161 	ksnprintf(dp->d_iocom.auto_lnk_span.cl_label,
162 		  sizeof(dp->d_iocom.auto_lnk_span.cl_label),
163 		  "%s/%s", hostname, devname);
164 	if (dp->d_info.d_serialno) {
165 		ksnprintf(dp->d_iocom.auto_lnk_span.fs_label,
166 			  sizeof(dp->d_iocom.auto_lnk_span.fs_label),
167 			  "%s", dp->d_info.d_serialno);
168 	}
169 
170 	kdmsg_iocom_autoinitiate(&dp->d_iocom, NULL);
171 
172 	return (0);
173 }
174 
175 int
176 disk_rcvdmsg(kdmsg_msg_t *msg)
177 {
178 	struct disk *dp = msg->state->iocom->handle;
179 
180 	/*
181 	 * Handle debug messages (these might not be in transactions)
182 	 */
183 	switch(msg->any.head.cmd & DMSGF_CMDSWMASK) {
184 	case DMSG_DBG_SHELL:
185 		/*
186 		 * Execute shell command (not supported atm)
187 		 */
188 		kdmsg_msg_reply(msg, DMSG_ERR_NOSUPP);
189 		return(0);
190 	case DMSG_DBG_SHELL | DMSGF_REPLY:
191 		if (msg->aux_data) {
192 			msg->aux_data[msg->aux_size - 1] = 0;
193 			kprintf("diskiocom: DEBUGMSG: %s\n", msg->aux_data);
194 		}
195 		return(0);
196 	}
197 
198 	/*
199 	 * All remaining messages must be in a transaction
200 	 *
201 	 * NOTE!  We are switching on the first message's command.  The
202 	 *	  actual message command within the transaction may be
203 	 *	  different (if streaming within a transaction).
204 	 */
205 	if (msg->state == &msg->state->iocom->state0) {
206 		kdmsg_msg_reply(msg, DMSG_ERR_NOSUPP);
207 		return(0);
208 	}
209 
210 	switch(msg->state->rxcmd & DMSGF_CMDSWMASK) {
211 	case DMSG_BLK_OPEN:
212 		disk_blk_open(dp, msg);
213 		break;
214 	case DMSG_BLK_READ:
215 		disk_blk_read(dp, msg);
216 		break;
217 	case DMSG_BLK_WRITE:
218 		disk_blk_write(dp, msg);
219 		break;
220 	case DMSG_BLK_FLUSH:
221 		disk_blk_flush(dp, msg);
222 		break;
223 	case DMSG_BLK_FREEBLKS:
224 		disk_blk_freeblks(dp, msg);
225 		break;
226 	default:
227 		if ((msg->any.head.cmd & DMSGF_REPLY) == 0) {
228 			if (msg->any.head.cmd & DMSGF_DELETE)
229 				kdmsg_msg_reply(msg, DMSG_ERR_NOSUPP);
230 			else
231 				kdmsg_msg_result(msg, DMSG_ERR_NOSUPP);
232 		}
233 		break;
234 	}
235 	return (0);
236 }
237 
238 static
239 void
240 disk_blk_open(struct disk *dp, kdmsg_msg_t *msg)
241 {
242 	struct dios_open *openst;
243 	int error = DMSG_ERR_NOSUPP;
244 	int fflags;
245 
246 	openst = msg->state->any.any;
247 	if ((msg->any.head.cmd & DMSGF_CMDSWMASK) == DMSG_BLK_OPEN) {
248 		if (openst == NULL) {
249 			openst = kmalloc(sizeof(*openst), M_DEVBUF,
250 						M_WAITOK | M_ZERO);
251 			msg->state->any.any = openst;
252 		}
253 		fflags = 0;
254 		if (msg->any.blk_open.modes & DMSG_BLKOPEN_RD)
255 			fflags = FREAD;
256 		if (msg->any.blk_open.modes & DMSG_BLKOPEN_WR)
257 			fflags |= FWRITE;
258 		error = dev_dopen(dp->d_rawdev, fflags, S_IFCHR, proc0.p_ucred, NULL);
259 		if (error) {
260 			error = DMSG_ERR_IO;
261 		} else {
262 			if (msg->any.blk_open.modes & DMSG_BLKOPEN_RD)
263 				++openst->openrd;
264 			if (msg->any.blk_open.modes & DMSG_BLKOPEN_WR)
265 				++openst->openwr;
266 		}
267 	}
268 #if 0
269 	if ((msg->any.head.cmd & DMSGF_CMDSWMASK) == DMSG_BLK_CLOSE &&
270 	    openst) {
271 		fflags = 0;
272 		if ((msg->any.blk_open.modes & DMSG_BLKOPEN_RD) &&
273 		    openst->openrd) {
274 			fflags = FREAD;
275 		}
276 		if ((msg->any.blk_open.modes & DMSG_BLKOPEN_WR) &&
277 		    openst->openwr) {
278 			fflags |= FWRITE;
279 		}
280 		error = dev_dclose(dp->d_rawdev, fflags, S_IFCHR, NULL);
281 		if (error) {
282 			error = DMSG_ERR_IO;
283 		} else {
284 			if (msg->any.blk_open.modes & DMSG_BLKOPEN_RD)
285 				--openst->openrd;
286 			if (msg->any.blk_open.modes & DMSG_BLKOPEN_WR)
287 				--openst->openwr;
288 		}
289 	}
290 #endif
291 	if (msg->any.head.cmd & DMSGF_DELETE) {
292 		if (openst) {
293 			while (openst->openrd && openst->openwr) {
294 				--openst->openrd;
295 				--openst->openwr;
296 				dev_dclose(dp->d_rawdev, FREAD|FWRITE, S_IFCHR, NULL);
297 			}
298 			while (openst->openrd) {
299 				--openst->openrd;
300 				dev_dclose(dp->d_rawdev, FREAD, S_IFCHR, NULL);
301 			}
302 			while (openst->openwr) {
303 				--openst->openwr;
304 				dev_dclose(dp->d_rawdev, FWRITE, S_IFCHR, NULL);
305 			}
306 			kfree(openst, M_DEVBUF);
307 			msg->state->any.any = NULL;
308 		}
309 		kdmsg_msg_reply(msg, error);
310 	} else {
311 		kdmsg_msg_result(msg, error);
312 	}
313 }
314 
315 static
316 void
317 disk_blk_read(struct disk *dp, kdmsg_msg_t *msg)
318 {
319 	struct dios_io *iost;
320 	struct buf *bp;
321 	struct bio *bio;
322 	int error = DMSG_ERR_NOSUPP;
323 	int reterr = 1;
324 
325 	/*
326 	 * Only DMSG_BLK_READ commands imply read ops.
327 	 */
328 	iost = msg->state->any.any;
329 	if ((msg->any.head.cmd & DMSGF_CMDSWMASK) == DMSG_BLK_READ) {
330 		if (msg->any.blk_read.bytes < DEV_BSIZE ||
331 		    msg->any.blk_read.bytes > MAXPHYS) {
332 			error = DMSG_ERR_PARAM;
333 			goto done;
334 		}
335 		if (iost == NULL) {
336 			iost = kmalloc(sizeof(*iost), M_DEVBUF,
337 				       M_WAITOK | M_ZERO);
338 			msg->state->any.any = iost;
339 		}
340 		reterr = 0;
341 		bp = geteblk(msg->any.blk_read.bytes);
342 		bio = &bp->b_bio1;
343 		bp->b_cmd = BUF_CMD_READ;
344 		bp->b_bcount = msg->any.blk_read.bytes;
345 		bp->b_resid = bp->b_bcount;
346 		bio->bio_offset = msg->any.blk_read.offset;
347 		bio->bio_caller_info1.ptr = msg->state;
348 		bio->bio_done = diskiodone;
349 		/* kdmsg_state_hold(msg->state); */
350 
351 		atomic_add_int(&iost->count, 1);
352 		if (msg->any.head.cmd & DMSGF_DELETE)
353 			iost->eof = 1;
354 		BUF_KERNPROC(bp);
355 		dev_dstrategy(dp->d_rawdev, bio);
356 	}
357 done:
358 	if (reterr) {
359 		if (msg->any.head.cmd & DMSGF_DELETE) {
360 			if (iost && iost->count == 0) {
361 				kfree(iost, M_DEVBUF);
362 				msg->state->any.any = NULL;
363 			}
364 			kdmsg_msg_reply(msg, error);
365 		} else {
366 			kdmsg_msg_result(msg, error);
367 		}
368 	}
369 }
370 
371 static
372 void
373 disk_blk_write(struct disk *dp, kdmsg_msg_t *msg)
374 {
375 	struct dios_io *iost;
376 	struct buf *bp;
377 	struct bio *bio;
378 	int error = DMSG_ERR_NOSUPP;
379 	int reterr = 1;
380 
381 	/*
382 	 * Only DMSG_BLK_WRITE commands imply read ops.
383 	 */
384 	iost = msg->state->any.any;
385 	if ((msg->any.head.cmd & DMSGF_CMDSWMASK) == DMSG_BLK_WRITE) {
386 		if (msg->any.blk_write.bytes < DEV_BSIZE ||
387 		    msg->any.blk_write.bytes > MAXPHYS) {
388 			error = DMSG_ERR_PARAM;
389 			goto done;
390 		}
391 		if (iost == NULL) {
392 			iost = kmalloc(sizeof(*iost), M_DEVBUF,
393 				       M_WAITOK | M_ZERO);
394 			msg->state->any.any = iost;
395 		}
396 
397 		/*
398 		 * Issue WRITE.  Short data implies zeros.  Try to optimize
399 		 * the buffer cache buffer for the case where we can just
400 		 * use the message's data pointer.
401 		 */
402 		reterr = 0;
403 		if (msg->aux_size >= msg->any.blk_write.bytes)
404 			bp = getpbuf(NULL);
405 		else
406 			bp = geteblk(msg->any.blk_write.bytes);
407 		bio = &bp->b_bio1;
408 		bp->b_cmd = BUF_CMD_WRITE;
409 		bp->b_bcount = msg->any.blk_write.bytes;
410 		bp->b_resid = bp->b_bcount;
411 		if (msg->aux_size >= msg->any.blk_write.bytes) {
412 			bp->b_data = msg->aux_data;
413 		} else {
414 			bcopy(msg->aux_data, bp->b_data, msg->aux_size);
415 			bzero(bp->b_data + msg->aux_size,
416 			      msg->any.blk_write.bytes - msg->aux_size);
417 		}
418 		bio->bio_offset = msg->any.blk_write.offset;
419 		bio->bio_caller_info1.ptr = msg->state;
420 		bio->bio_done = diskiodone;
421 		/* kdmsg_state_hold(msg->state); */
422 
423 		atomic_add_int(&iost->count, 1);
424 		if (msg->any.head.cmd & DMSGF_DELETE)
425 			iost->eof = 1;
426 		BUF_KERNPROC(bp);
427 		dev_dstrategy(dp->d_rawdev, bio);
428 	}
429 done:
430 	if (reterr) {
431 		if (msg->any.head.cmd & DMSGF_DELETE) {
432 			if (iost && iost->count == 0) {
433 				kfree(iost, M_DEVBUF);
434 				msg->state->any.any = NULL;
435 			}
436 			kdmsg_msg_reply(msg, error);
437 		} else {
438 			kdmsg_msg_result(msg, error);
439 		}
440 	}
441 }
442 
443 static
444 void
445 disk_blk_flush(struct disk *dp, kdmsg_msg_t *msg)
446 {
447 	struct dios_io *iost;
448 	struct buf *bp;
449 	struct bio *bio;
450 	int error = DMSG_ERR_NOSUPP;
451 	int reterr = 1;
452 
453 	/*
454 	 * Only DMSG_BLK_FLUSH commands imply read ops.
455 	 */
456 	iost = msg->state->any.any;
457 	if ((msg->any.head.cmd & DMSGF_CMDSWMASK) == DMSG_BLK_FLUSH) {
458 		if (iost == NULL) {
459 			iost = kmalloc(sizeof(*iost), M_DEVBUF,
460 				       M_WAITOK | M_ZERO);
461 			msg->state->any.any = iost;
462 		}
463 		reterr = 0;
464 		bp = getpbuf(NULL);
465 		bio = &bp->b_bio1;
466 		bp->b_cmd = BUF_CMD_FLUSH;
467 		bp->b_bcount = msg->any.blk_flush.bytes;
468 		bp->b_resid = 0;
469 		bio->bio_offset = msg->any.blk_flush.offset;
470 		bio->bio_caller_info1.ptr = msg->state;
471 		bio->bio_done = diskiodone;
472 		/* kdmsg_state_hold(msg->state); */
473 
474 		atomic_add_int(&iost->count, 1);
475 		if (msg->any.head.cmd & DMSGF_DELETE)
476 			iost->eof = 1;
477 		BUF_KERNPROC(bp);
478 		dev_dstrategy(dp->d_rawdev, bio);
479 	}
480 	if (reterr) {
481 		if (msg->any.head.cmd & DMSGF_DELETE) {
482 			if (iost && iost->count == 0) {
483 				kfree(iost, M_DEVBUF);
484 				msg->state->any.any = NULL;
485 			}
486 			kdmsg_msg_reply(msg, error);
487 		} else {
488 			kdmsg_msg_result(msg, error);
489 		}
490 	}
491 }
492 
493 static
494 void
495 disk_blk_freeblks(struct disk *dp, kdmsg_msg_t *msg)
496 {
497 	struct dios_io *iost;
498 	struct buf *bp;
499 	struct bio *bio;
500 	int error = DMSG_ERR_NOSUPP;
501 	int reterr = 1;
502 
503 	/*
504 	 * Only DMSG_BLK_FREEBLKS commands imply read ops.
505 	 */
506 	iost = msg->state->any.any;
507 	if ((msg->any.head.cmd & DMSGF_CMDSWMASK) == DMSG_BLK_FREEBLKS) {
508 		if (iost == NULL) {
509 			iost = kmalloc(sizeof(*iost), M_DEVBUF,
510 				       M_WAITOK | M_ZERO);
511 			msg->state->any.any = iost;
512 		}
513 		reterr = 0;
514 		bp = getpbuf(NULL);
515 		bio = &bp->b_bio1;
516 		bp->b_cmd = BUF_CMD_FREEBLKS;
517 		bp->b_bcount = msg->any.blk_freeblks.bytes;
518 		bp->b_resid = 0;
519 		bio->bio_offset = msg->any.blk_freeblks.offset;
520 		bio->bio_caller_info1.ptr = msg->state;
521 		bio->bio_done = diskiodone;
522 		/* kdmsg_state_hold(msg->state); */
523 
524 		atomic_add_int(&iost->count, 1);
525 		if (msg->any.head.cmd & DMSGF_DELETE)
526 			iost->eof = 1;
527 		BUF_KERNPROC(bp);
528 		dev_dstrategy(dp->d_rawdev, bio);
529 	}
530 	if (reterr) {
531 		if (msg->any.head.cmd & DMSGF_DELETE) {
532 			if (iost && iost->count == 0) {
533 				kfree(iost, M_DEVBUF);
534 				msg->state->any.any = NULL;
535 			}
536 			kdmsg_msg_reply(msg, error);
537 		} else {
538 			kdmsg_msg_result(msg, error);
539 		}
540 	}
541 }
542 
543 static
544 void
545 diskiodone(struct bio *bio)
546 {
547 	struct buf *bp = bio->bio_buf;
548 	kdmsg_state_t *state = bio->bio_caller_info1.ptr;
549 	kdmsg_msg_t *rmsg;
550 	struct dios_io *iost = state->any.any;
551 	int error;
552 	int resid = 0;
553 	int bytes;
554 	uint32_t cmd;
555 	void *data;
556 
557 	cmd = DMSG_LNK_ERROR;
558 	data = NULL;
559 	bytes = 0;
560 
561 	switch(bp->b_cmd) {
562 	case BUF_CMD_READ:
563 		cmd = DMSG_LNK_ERROR;
564 		data = bp->b_data;
565 		bytes = bp->b_bcount;
566 		/* fall through */
567 	case BUF_CMD_WRITE:
568 		if (bp->b_flags & B_ERROR) {
569 			error = bp->b_error;
570 		} else {
571 			error = 0;
572 			resid = bp->b_resid;
573 		}
574 		break;
575 	case BUF_CMD_FLUSH:
576 	case BUF_CMD_FREEBLKS:
577 		if (bp->b_flags & B_ERROR)
578 			error = bp->b_error;
579 		else
580 			error = 0;
581 		break;
582 	default:
583 		panic("diskiodone: Unknown bio cmd = %d\n",
584 		      bio->bio_buf->b_cmd);
585 		error = 0;	/* avoid compiler warning */
586 		break;		/* NOT REACHED */
587 	}
588 
589 	/*
590 	 * Convert error to DMSG_ERR_* code.
591 	 */
592 	if (error)
593 		error = DMSG_ERR_IO;
594 
595 	/*
596 	 * Convert LNK_ERROR or BLK_ERROR if non-zero resid.  READS will
597 	 * have already converted cmd to BLK_ERROR and set up data to return.
598 	 */
599 	if (resid && cmd == DMSG_LNK_ERROR)
600 		cmd = DMSG_BLK_ERROR;
601 	/* XXX txcmd is delayed so this won't work for streaming */
602 	if ((state->txcmd & DMSGF_CREATE) == 0)	/* assume serialized */
603 		cmd |= DMSGF_CREATE;
604 	if (iost->eof) {
605 		if (atomic_fetchadd_int(&iost->count, -1) == 1)
606 			cmd |= DMSGF_DELETE;
607 	} else {
608 		atomic_add_int(&iost->count, -1);
609 	}
610 	cmd |= DMSGF_REPLY;
611 
612 	/*
613 	 * Allocate a basic or extended reply.  Be careful not to populate
614 	 * extended header fields unless we allocated an extended reply.
615 	 */
616 	rmsg = kdmsg_msg_alloc(state, cmd, NULL, 0);
617 	if (data) {
618 		rmsg->aux_data = kmalloc(bytes, state->iocom->mmsg, M_INTWAIT);
619 		rmsg->aux_size = bytes;
620 		rmsg->flags |= KDMSG_FLAG_AUXALLOC;
621 		bcopy(data, rmsg->aux_data, bytes);
622 	}
623 	rmsg->any.blk_error.head.error = error;
624 	if ((cmd & DMSGF_BASECMDMASK) == DMSG_BLK_ERROR)
625 		rmsg->any.blk_error.resid = resid;
626 	bio->bio_caller_info1.ptr = NULL;
627 	/* kdmsg_state_drop(state); */
628 	kdmsg_msg_write(rmsg);
629 	if (bp->b_flags & B_PAGING) {
630 		relpbuf(bio->bio_buf, NULL);
631 	} else {
632 		bp->b_flags |= B_INVAL | B_AGE;
633 		brelse(bp);
634 	}
635 }
636