1 2/* 3 osdblk.c -- Export a single SCSI OSD object as a Linux block device 4 5 6 Copyright 2009 Red Hat, Inc. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; see the file COPYING. If not, write to 19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 20 21 22 Instructions for use 23 -------------------- 24 25 1) Map a Linux block device to an existing OSD object. 26 27 In this example, we will use partition id 1234, object id 5678, 28 OSD device /dev/osd1. 29 30 $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add 31 32 33 2) List all active blkdev<->object mappings. 34 35 In this example, we have performed step #1 twice, creating two blkdevs, 36 mapped to two separate OSD objects. 37 38 $ cat /sys/class/osdblk/list 39 0 174 1234 5678 /dev/osd1 40 1 179 1994 897123 /dev/osd0 41 42 The columns, in order, are: 43 - blkdev unique id 44 - blkdev assigned major 45 - OSD object partition id 46 - OSD object id 47 - OSD device 48 49 50 3) Remove an active blkdev<->object mapping. 51 52 In this example, we remove the mapping with blkdev unique id 1. 53 54 $ echo 1 > /sys/class/osdblk/remove 55 56 57 NOTE: The actual creation and deletion of OSD objects is outside the scope 58 of this driver. 59 60 */ 61 62#include <linux/kernel.h> 63#include <linux/device.h> 64#include <linux/module.h> 65#include <linux/fs.h> 66#include <linux/slab.h> 67#include <scsi/osd_initiator.h> 68#include <scsi/osd_attributes.h> 69#include <scsi/osd_sec.h> 70#include <scsi/scsi_device.h> 71 72#define DRV_NAME "osdblk" 73#define PFX DRV_NAME ": " 74 75/* #define _OSDBLK_DEBUG */ 76#ifdef _OSDBLK_DEBUG 77#define OSDBLK_DEBUG(fmt, a...) \ 78 printk(KERN_NOTICE "osdblk @%s:%d: " fmt, __func__, __LINE__, ##a) 79#else 80#define OSDBLK_DEBUG(fmt, a...) \ 81 do { if (0) printk(fmt, ##a); } while (0) 82#endif 83 84MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>"); 85MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko"); 86MODULE_LICENSE("GPL"); 87 88struct osdblk_device; 89 90enum { 91 OSDBLK_MINORS_PER_MAJOR = 256, /* max minors per blkdev */ 92 OSDBLK_MAX_REQ = 32, /* max parallel requests */ 93 OSDBLK_OP_TIMEOUT = 4 * 60, /* sync OSD req timeout */ 94}; 95 96struct osdblk_request { 97 struct request *rq; /* blk layer request */ 98 struct bio *bio; /* cloned bio */ 99 struct osdblk_device *osdev; /* associated blkdev */ 100}; 101 102struct osdblk_device { 103 int id; /* blkdev unique id */ 104 105 int major; /* blkdev assigned major */ 106 struct gendisk *disk; /* blkdev's gendisk and rq */ 107 struct request_queue *q; 108 109 struct osd_dev *osd; /* associated OSD */ 110 111 char name[32]; /* blkdev name, e.g. osdblk34 */ 112 113 spinlock_t lock; /* queue lock */ 114 115 struct osd_obj_id obj; /* OSD partition, obj id */ 116 uint8_t obj_cred[OSD_CAP_LEN]; /* OSD cred */ 117 118 struct osdblk_request req[OSDBLK_MAX_REQ]; /* request table */ 119 120 struct list_head node; 121 122 char osd_path[0]; /* OSD device path */ 123}; 124 125static struct class *class_osdblk; /* /sys/class/osdblk */ 126static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */ 127static LIST_HEAD(osdblkdev_list); 128 129static const struct block_device_operations osdblk_bd_ops = { 130 .owner = THIS_MODULE, 131}; 132 133static const struct osd_attr g_attr_logical_length = ATTR_DEF( 134 OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8); 135 136static void osdblk_make_credential(u8 cred_a[OSD_CAP_LEN], 137 const struct osd_obj_id *obj) 138{ 139 osd_sec_init_nosec_doall_caps(cred_a, obj, false, true); 140} 141 142/* copied from exofs; move to libosd? */ 143/* 144 * Perform a synchronous OSD operation. copied from exofs; move to libosd? 145 */ 146static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential) 147{ 148 int ret; 149 150 or->timeout = timeout; 151 ret = osd_finalize_request(or, 0, credential, NULL); 152 if (ret) 153 return ret; 154 155 ret = osd_execute_request(or); 156 157 /* osd_req_decode_sense(or, ret); */ 158 return ret; 159} 160 161/* 162 * Perform an asynchronous OSD operation. copied from exofs; move to libosd? 163 */ 164static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done, 165 void *caller_context, u8 *cred) 166{ 167 int ret; 168 169 ret = osd_finalize_request(or, 0, cred, NULL); 170 if (ret) 171 return ret; 172 173 ret = osd_execute_request_async(or, async_done, caller_context); 174 175 return ret; 176} 177 178/* copied from exofs; move to libosd? */ 179static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr) 180{ 181 struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */ 182 void *iter = NULL; 183 int nelem; 184 185 do { 186 nelem = 1; 187 osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter); 188 if ((cur_attr.attr_page == attr->attr_page) && 189 (cur_attr.attr_id == attr->attr_id)) { 190 attr->len = cur_attr.len; 191 attr->val_ptr = cur_attr.val_ptr; 192 return 0; 193 } 194 } while (iter); 195 196 return -EIO; 197} 198 199static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out) 200{ 201 struct osd_request *or; 202 struct osd_attr attr; 203 int ret; 204 205 /* start request */ 206 or = osd_start_request(osdev->osd, GFP_KERNEL); 207 if (!or) 208 return -ENOMEM; 209 210 /* create a get-attributes(length) request */ 211 osd_req_get_attributes(or, &osdev->obj); 212 213 osd_req_add_get_attr_list(or, &g_attr_logical_length, 1); 214 215 /* execute op synchronously */ 216 ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred); 217 if (ret) 218 goto out; 219 220 /* extract length from returned attribute info */ 221 attr = g_attr_logical_length; 222 ret = extract_attr_from_req(or, &attr); 223 if (ret) 224 goto out; 225 226 *size_out = get_unaligned_be64(attr.val_ptr); 227 228out: 229 osd_end_request(or); 230 return ret; 231 232} 233 234static void osdblk_osd_complete(struct osd_request *or, void *private) 235{ 236 struct osdblk_request *orq = private; 237 struct osd_sense_info osi; 238 int ret = osd_req_decode_sense(or, &osi); 239 240 if (ret) { 241 ret = -EIO; 242 OSDBLK_DEBUG("osdblk_osd_complete with err=%d\n", ret); 243 } 244 245 /* complete OSD request */ 246 osd_end_request(or); 247 248 /* complete request passed to osdblk by block layer */ 249 __blk_end_request_all(orq->rq, ret); 250} 251 252static void bio_chain_put(struct bio *chain) 253{ 254 struct bio *tmp; 255 256 while (chain) { 257 tmp = chain; 258 chain = chain->bi_next; 259 260 bio_put(tmp); 261 } 262} 263 264static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask) 265{ 266 struct bio *tmp, *new_chain = NULL, *tail = NULL; 267 268 while (old_chain) { 269 tmp = bio_clone_kmalloc(old_chain, gfpmask); 270 if (!tmp) 271 goto err_out; 272 273 tmp->bi_bdev = NULL; 274 gfpmask &= ~__GFP_WAIT; 275 tmp->bi_next = NULL; 276 277 if (!new_chain) 278 new_chain = tail = tmp; 279 else { 280 tail->bi_next = tmp; 281 tail = tmp; 282 } 283 284 old_chain = old_chain->bi_next; 285 } 286 287 return new_chain; 288 289err_out: 290 OSDBLK_DEBUG("bio_chain_clone with err\n"); 291 bio_chain_put(new_chain); 292 return NULL; 293} 294 295static void osdblk_rq_fn(struct request_queue *q) 296{ 297 struct osdblk_device *osdev = q->queuedata; 298 299 while (1) { 300 struct request *rq; 301 struct osdblk_request *orq; 302 struct osd_request *or; 303 struct bio *bio; 304 bool do_write, do_flush; 305 306 /* peek at request from block layer */ 307 rq = blk_fetch_request(q); 308 if (!rq) 309 break; 310 311 /* filter out block requests we don't understand */ 312 if (rq->cmd_type != REQ_TYPE_FS) { 313 blk_end_request_all(rq, 0); 314 continue; 315 } 316 317 /* deduce our operation (read, write, flush) */ 318 /* I wish the block layer simplified cmd_type/cmd_flags/cmd[] 319 * into a clearly defined set of RPC commands: 320 * read, write, flush, scsi command, power mgmt req, 321 * driver-specific, etc. 322 */ 323 324 do_flush = rq->cmd_flags & REQ_FLUSH; 325 do_write = (rq_data_dir(rq) == WRITE); 326 327 if (!do_flush) { /* osd_flush does not use a bio */ 328 /* a bio clone to be passed down to OSD request */ 329 bio = bio_chain_clone(rq->bio, GFP_ATOMIC); 330 if (!bio) 331 break; 332 } else 333 bio = NULL; 334 335 /* alloc internal OSD request, for OSD command execution */ 336 or = osd_start_request(osdev->osd, GFP_ATOMIC); 337 if (!or) { 338 bio_chain_put(bio); 339 OSDBLK_DEBUG("osd_start_request with err\n"); 340 break; 341 } 342 343 orq = &osdev->req[rq->tag]; 344 orq->rq = rq; 345 orq->bio = bio; 346 orq->osdev = osdev; 347 348 /* init OSD command: flush, write or read */ 349 if (do_flush) 350 osd_req_flush_object(or, &osdev->obj, 351 OSD_CDB_FLUSH_ALL, 0, 0); 352 else if (do_write) 353 osd_req_write(or, &osdev->obj, blk_rq_pos(rq) * 512ULL, 354 bio, blk_rq_bytes(rq)); 355 else 356 osd_req_read(or, &osdev->obj, blk_rq_pos(rq) * 512ULL, 357 bio, blk_rq_bytes(rq)); 358 359 OSDBLK_DEBUG("%s 0x%x bytes at 0x%llx\n", 360 do_flush ? "flush" : do_write ? 361 "write" : "read", blk_rq_bytes(rq), 362 blk_rq_pos(rq) * 512ULL); 363 364 /* begin OSD command execution */ 365 if (osd_async_op(or, osdblk_osd_complete, orq, 366 osdev->obj_cred)) { 367 osd_end_request(or); 368 blk_requeue_request(q, rq); 369 bio_chain_put(bio); 370 OSDBLK_DEBUG("osd_execute_request_async with err\n"); 371 break; 372 } 373 374 /* remove the special 'flush' marker, now that the command 375 * is executing 376 */ 377 rq->special = NULL; 378 } 379} 380 381static void osdblk_free_disk(struct osdblk_device *osdev) 382{ 383 struct gendisk *disk = osdev->disk; 384 385 if (!disk) 386 return; 387 388 if (disk->flags & GENHD_FL_UP) 389 del_gendisk(disk); 390 if (disk->queue) 391 blk_cleanup_queue(disk->queue); 392 put_disk(disk); 393} 394 395static int osdblk_init_disk(struct osdblk_device *osdev) 396{ 397 struct gendisk *disk; 398 struct request_queue *q; 399 int rc; 400 u64 obj_size = 0; 401 402 /* contact OSD, request size info about the object being mapped */ 403 rc = osdblk_get_obj_size(osdev, &obj_size); 404 if (rc) 405 return rc; 406 407 /* create gendisk info */ 408 disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR); 409 if (!disk) 410 return -ENOMEM; 411 412 sprintf(disk->disk_name, DRV_NAME "%d", osdev->id); 413 disk->major = osdev->major; 414 disk->first_minor = 0; 415 disk->fops = &osdblk_bd_ops; 416 disk->private_data = osdev; 417 418 /* init rq */ 419 q = blk_init_queue(osdblk_rq_fn, &osdev->lock); 420 if (!q) { 421 put_disk(disk); 422 return -ENOMEM; 423 } 424 425 /* switch queue to TCQ mode; allocate tag map */ 426 rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL); 427 if (rc) { 428 blk_cleanup_queue(q); 429 put_disk(disk); 430 return rc; 431 } 432 433 /* Set our limits to the lower device limits, because osdblk cannot 434 * sleep when allocating a lower-request and therefore cannot be 435 * bouncing. 436 */ 437 blk_queue_stack_limits(q, osd_request_queue(osdev->osd)); 438 439 blk_queue_prep_rq(q, blk_queue_start_tag); 440 blk_queue_flush(q, REQ_FLUSH); 441 442 disk->queue = q; 443 444 q->queuedata = osdev; 445 446 osdev->disk = disk; 447 osdev->q = q; 448 449 /* finally, announce the disk to the world */ 450 set_capacity(disk, obj_size / 512ULL); 451 add_disk(disk); 452 453 printk(KERN_INFO "%s: Added of size 0x%llx\n", 454 disk->disk_name, (unsigned long long)obj_size); 455 456 return 0; 457} 458 459/******************************************************************** 460 * /sys/class/osdblk/ 461 * add map OSD object to blkdev 462 * remove unmap OSD object 463 * list show mappings 464 *******************************************************************/ 465 466static void class_osdblk_release(struct class *cls) 467{ 468 kfree(cls); 469} 470 471static ssize_t class_osdblk_list(struct class *c, 472 struct class_attribute *attr, 473 char *data) 474{ 475 int n = 0; 476 struct list_head *tmp; 477 478 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); 479 480 list_for_each(tmp, &osdblkdev_list) { 481 struct osdblk_device *osdev; 482 483 osdev = list_entry(tmp, struct osdblk_device, node); 484 485 n += sprintf(data+n, "%d %d %llu %llu %s\n", 486 osdev->id, 487 osdev->major, 488 osdev->obj.partition, 489 osdev->obj.id, 490 osdev->osd_path); 491 } 492 493 mutex_unlock(&ctl_mutex); 494 return n; 495} 496 497static ssize_t class_osdblk_add(struct class *c, 498 struct class_attribute *attr, 499 const char *buf, size_t count) 500{ 501 struct osdblk_device *osdev; 502 ssize_t rc; 503 int irc, new_id = 0; 504 struct list_head *tmp; 505 506 if (!try_module_get(THIS_MODULE)) 507 return -ENODEV; 508 509 /* new osdblk_device object */ 510 osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL); 511 if (!osdev) { 512 rc = -ENOMEM; 513 goto err_out_mod; 514 } 515 516 /* static osdblk_device initialization */ 517 spin_lock_init(&osdev->lock); 518 INIT_LIST_HEAD(&osdev->node); 519 520 /* generate unique id: find highest unique id, add one */ 521 522 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); 523 524 list_for_each(tmp, &osdblkdev_list) { 525 struct osdblk_device *osdev; 526 527 osdev = list_entry(tmp, struct osdblk_device, node); 528 if (osdev->id > new_id) 529 new_id = osdev->id + 1; 530 } 531 532 osdev->id = new_id; 533 534 /* add to global list */ 535 list_add_tail(&osdev->node, &osdblkdev_list); 536 537 mutex_unlock(&ctl_mutex); 538 539 /* parse add command */ 540 if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id, 541 osdev->osd_path) != 3) { 542 rc = -EINVAL; 543 goto err_out_slot; 544 } 545 546 /* initialize rest of new object */ 547 sprintf(osdev->name, DRV_NAME "%d", osdev->id); 548 549 /* contact requested OSD */ 550 osdev->osd = osduld_path_lookup(osdev->osd_path); 551 if (IS_ERR(osdev->osd)) { 552 rc = PTR_ERR(osdev->osd); 553 goto err_out_slot; 554 } 555 556 /* build OSD credential */ 557 osdblk_make_credential(osdev->obj_cred, &osdev->obj); 558 559 /* register our block device */ 560 irc = register_blkdev(0, osdev->name); 561 if (irc < 0) { 562 rc = irc; 563 goto err_out_osd; 564 } 565 566 osdev->major = irc; 567 568 /* set up and announce blkdev mapping */ 569 rc = osdblk_init_disk(osdev); 570 if (rc) 571 goto err_out_blkdev; 572 573 return count; 574 575err_out_blkdev: 576 unregister_blkdev(osdev->major, osdev->name); 577err_out_osd: 578 osduld_put_device(osdev->osd); 579err_out_slot: 580 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); 581 list_del_init(&osdev->node); 582 mutex_unlock(&ctl_mutex); 583 584 kfree(osdev); 585err_out_mod: 586 OSDBLK_DEBUG("Error adding device %s\n", buf); 587 module_put(THIS_MODULE); 588 return rc; 589} 590 591static ssize_t class_osdblk_remove(struct class *c, 592 struct class_attribute *attr, 593 const char *buf, 594 size_t count) 595{ 596 struct osdblk_device *osdev = NULL; 597 int target_id, rc; 598 unsigned long ul; 599 struct list_head *tmp; 600 601 rc = kstrtoul(buf, 10, &ul); 602 if (rc) 603 return rc; 604 605 /* convert to int; abort if we lost anything in the conversion */ 606 target_id = (int) ul; 607 if (target_id != ul) 608 return -EINVAL; 609 610 /* remove object from list immediately */ 611 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); 612 613 list_for_each(tmp, &osdblkdev_list) { 614 osdev = list_entry(tmp, struct osdblk_device, node); 615 if (osdev->id == target_id) { 616 list_del_init(&osdev->node); 617 break; 618 } 619 osdev = NULL; 620 } 621 622 mutex_unlock(&ctl_mutex); 623 624 if (!osdev) 625 return -ENOENT; 626 627 /* clean up and free blkdev and associated OSD connection */ 628 osdblk_free_disk(osdev); 629 unregister_blkdev(osdev->major, osdev->name); 630 osduld_put_device(osdev->osd); 631 kfree(osdev); 632 633 /* release module ref */ 634 module_put(THIS_MODULE); 635 636 return count; 637} 638 639static struct class_attribute class_osdblk_attrs[] = { 640 __ATTR(add, 0200, NULL, class_osdblk_add), 641 __ATTR(remove, 0200, NULL, class_osdblk_remove), 642 __ATTR(list, 0444, class_osdblk_list, NULL), 643 __ATTR_NULL 644}; 645 646static int osdblk_sysfs_init(void) 647{ 648 int ret = 0; 649 650 /* 651 * create control files in sysfs 652 * /sys/class/osdblk/... 653 */ 654 class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL); 655 if (!class_osdblk) 656 return -ENOMEM; 657 658 class_osdblk->name = DRV_NAME; 659 class_osdblk->owner = THIS_MODULE; 660 class_osdblk->class_release = class_osdblk_release; 661 class_osdblk->class_attrs = class_osdblk_attrs; 662 663 ret = class_register(class_osdblk); 664 if (ret) { 665 kfree(class_osdblk); 666 class_osdblk = NULL; 667 printk(PFX "failed to create class osdblk\n"); 668 return ret; 669 } 670 671 return 0; 672} 673 674static void osdblk_sysfs_cleanup(void) 675{ 676 if (class_osdblk) 677 class_destroy(class_osdblk); 678 class_osdblk = NULL; 679} 680 681static int __init osdblk_init(void) 682{ 683 int rc; 684 685 rc = osdblk_sysfs_init(); 686 if (rc) 687 return rc; 688 689 return 0; 690} 691 692static void __exit osdblk_exit(void) 693{ 694 osdblk_sysfs_cleanup(); 695} 696 697module_init(osdblk_init); 698module_exit(osdblk_exit); 699 700