1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2018 Cambridge Greys Ltd 4 * Copyright (C) 2015-2016 Anton Ivanov (aivanov@brocade.com) 5 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) 6 */ 7 8 /* 2001-09-28...2002-04-17 9 * Partition stuff by James_McMechan@hotmail.com 10 * old style ubd by setting UBD_SHIFT to 0 11 * 2002-09-27...2002-10-18 massive tinkering for 2.5 12 * partitions have changed in 2.5 13 * 2003-01-29 more tinkering for 2.5.59-1 14 * This should now address the sysfs problems and has 15 * the symlink for devfs to allow for booting with 16 * the common /dev/ubd/discX/... names rather than 17 * only /dev/ubdN/discN this version also has lots of 18 * clean ups preparing for ubd-many. 19 * James McMechan 20 */ 21 22 #define UBD_SHIFT 4 23 24 #include <linux/module.h> 25 #include <linux/init.h> 26 #include <linux/blkdev.h> 27 #include <linux/blk-mq.h> 28 #include <linux/ata.h> 29 #include <linux/hdreg.h> 30 #include <linux/major.h> 31 #include <linux/cdrom.h> 32 #include <linux/proc_fs.h> 33 #include <linux/seq_file.h> 34 #include <linux/ctype.h> 35 #include <linux/slab.h> 36 #include <linux/vmalloc.h> 37 #include <linux/platform_device.h> 38 #include <linux/scatterlist.h> 39 #include <kern_util.h> 40 #include "mconsole_kern.h" 41 #include <init.h> 42 #include <irq_kern.h> 43 #include "ubd.h" 44 #include <os.h> 45 #include "cow.h" 46 47 /* Max request size is determined by sector mask - 32K */ 48 #define UBD_MAX_REQUEST (8 * sizeof(long)) 49 50 struct io_desc { 51 char *buffer; 52 unsigned long length; 53 unsigned long sector_mask; 54 unsigned long long cow_offset; 55 unsigned long bitmap_words[2]; 56 }; 57 58 struct io_thread_req { 59 struct request *req; 60 int fds[2]; 61 unsigned long offsets[2]; 62 unsigned long long offset; 63 int sectorsize; 64 int error; 65 66 int desc_cnt; 67 /* io_desc has to be the last element of the struct */ 68 struct io_desc io_desc[]; 69 }; 70 71 72 static struct io_thread_req * (*irq_req_buffer)[]; 73 static struct io_thread_req *irq_remainder; 74 static int irq_remainder_size; 75 76 static struct io_thread_req * (*io_req_buffer)[]; 77 static struct io_thread_req *io_remainder; 78 static int io_remainder_size; 79 80 81 82 static inline int ubd_test_bit(__u64 bit, unsigned char *data) 83 { 84 __u64 n; 85 int bits, off; 86 87 bits = sizeof(data[0]) * 8; 88 n = bit / bits; 89 off = bit % bits; 90 return (data[n] & (1 << off)) != 0; 91 } 92 93 static inline void ubd_set_bit(__u64 bit, unsigned char *data) 94 { 95 __u64 n; 96 int bits, off; 97 98 bits = sizeof(data[0]) * 8; 99 n = bit / bits; 100 off = bit % bits; 101 data[n] |= (1 << off); 102 } 103 /*End stuff from ubd_user.h*/ 104 105 #define DRIVER_NAME "uml-blkdev" 106 107 static DEFINE_MUTEX(ubd_lock); 108 109 static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode, 110 unsigned int cmd, unsigned long arg); 111 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); 112 113 #define MAX_DEV (16) 114 115 static const struct block_device_operations ubd_blops = { 116 .owner = THIS_MODULE, 117 .ioctl = ubd_ioctl, 118 .compat_ioctl = blkdev_compat_ptr_ioctl, 119 .getgeo = ubd_getgeo, 120 }; 121 122 #ifdef CONFIG_BLK_DEV_UBD_SYNC 123 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 124 .cl = 1 }) 125 #else 126 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 127 .cl = 1 }) 128 #endif 129 static struct openflags global_openflags = OPEN_FLAGS; 130 131 struct cow { 132 /* backing file name */ 133 char *file; 134 /* backing file fd */ 135 int fd; 136 unsigned long *bitmap; 137 unsigned long bitmap_len; 138 int bitmap_offset; 139 int data_offset; 140 }; 141 142 #define MAX_SG 64 143 144 struct ubd { 145 /* name (and fd, below) of the file opened for writing, either the 146 * backing or the cow file. */ 147 char *file; 148 char *serial; 149 int fd; 150 __u64 size; 151 struct openflags boot_openflags; 152 struct openflags openflags; 153 unsigned shared:1; 154 unsigned no_cow:1; 155 unsigned no_trim:1; 156 struct cow cow; 157 struct platform_device pdev; 158 struct gendisk *disk; 159 struct blk_mq_tag_set tag_set; 160 spinlock_t lock; 161 }; 162 163 #define DEFAULT_COW { \ 164 .file = NULL, \ 165 .fd = -1, \ 166 .bitmap = NULL, \ 167 .bitmap_offset = 0, \ 168 .data_offset = 0, \ 169 } 170 171 #define DEFAULT_UBD { \ 172 .file = NULL, \ 173 .serial = NULL, \ 174 .fd = -1, \ 175 .size = -1, \ 176 .boot_openflags = OPEN_FLAGS, \ 177 .openflags = OPEN_FLAGS, \ 178 .no_cow = 0, \ 179 .no_trim = 0, \ 180 .shared = 0, \ 181 .cow = DEFAULT_COW, \ 182 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \ 183 } 184 185 /* Protected by ubd_lock */ 186 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD }; 187 188 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 189 const struct blk_mq_queue_data *bd); 190 191 static int fake_ide_setup(char *str) 192 { 193 pr_warn("The fake_ide option has been removed\n"); 194 return 1; 195 } 196 __setup("fake_ide", fake_ide_setup); 197 198 __uml_help(fake_ide_setup, 199 "fake_ide\n" 200 " Obsolete stub.\n\n" 201 ); 202 203 static int parse_unit(char **ptr) 204 { 205 char *str = *ptr, *end; 206 int n = -1; 207 208 if(isdigit(*str)) { 209 n = simple_strtoul(str, &end, 0); 210 if(end == str) 211 return -1; 212 *ptr = end; 213 } 214 else if (('a' <= *str) && (*str <= 'z')) { 215 n = *str - 'a'; 216 str++; 217 *ptr = str; 218 } 219 return n; 220 } 221 222 /* If *index_out == -1 at exit, the passed option was a general one; 223 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it 224 * should not be freed on exit. 225 */ 226 static int ubd_setup_common(char *str, int *index_out, char **error_out) 227 { 228 struct ubd *ubd_dev; 229 struct openflags flags = global_openflags; 230 char *file, *backing_file, *serial; 231 int n, err = 0, i; 232 233 if(index_out) *index_out = -1; 234 n = *str; 235 if(n == '='){ 236 str++; 237 if(!strcmp(str, "sync")){ 238 global_openflags = of_sync(global_openflags); 239 return err; 240 } 241 242 pr_warn("fake major not supported any more\n"); 243 return 0; 244 } 245 246 n = parse_unit(&str); 247 if(n < 0){ 248 *error_out = "Couldn't parse device number"; 249 return -EINVAL; 250 } 251 if(n >= MAX_DEV){ 252 *error_out = "Device number out of range"; 253 return 1; 254 } 255 256 err = -EBUSY; 257 mutex_lock(&ubd_lock); 258 259 ubd_dev = &ubd_devs[n]; 260 if(ubd_dev->file != NULL){ 261 *error_out = "Device is already configured"; 262 goto out; 263 } 264 265 if (index_out) 266 *index_out = n; 267 268 err = -EINVAL; 269 for (i = 0; i < sizeof("rscdt="); i++) { 270 switch (*str) { 271 case 'r': 272 flags.w = 0; 273 break; 274 case 's': 275 flags.s = 1; 276 break; 277 case 'd': 278 ubd_dev->no_cow = 1; 279 break; 280 case 'c': 281 ubd_dev->shared = 1; 282 break; 283 case 't': 284 ubd_dev->no_trim = 1; 285 break; 286 case '=': 287 str++; 288 goto break_loop; 289 default: 290 *error_out = "Expected '=' or flag letter " 291 "(r, s, c, t or d)"; 292 goto out; 293 } 294 str++; 295 } 296 297 if (*str == '=') 298 *error_out = "Too many flags specified"; 299 else 300 *error_out = "Missing '='"; 301 goto out; 302 303 break_loop: 304 file = strsep(&str, ",:"); 305 if (*file == '\0') 306 file = NULL; 307 308 backing_file = strsep(&str, ",:"); 309 if (backing_file && *backing_file == '\0') 310 backing_file = NULL; 311 312 serial = strsep(&str, ",:"); 313 if (serial && *serial == '\0') 314 serial = NULL; 315 316 if (backing_file && ubd_dev->no_cow) { 317 *error_out = "Can't specify both 'd' and a cow file"; 318 goto out; 319 } 320 321 err = 0; 322 ubd_dev->file = file; 323 ubd_dev->cow.file = backing_file; 324 ubd_dev->serial = serial; 325 ubd_dev->boot_openflags = flags; 326 out: 327 mutex_unlock(&ubd_lock); 328 return err; 329 } 330 331 static int ubd_setup(char *str) 332 { 333 char *error; 334 int err; 335 336 err = ubd_setup_common(str, NULL, &error); 337 if(err) 338 printk(KERN_ERR "Failed to initialize device with \"%s\" : " 339 "%s\n", str, error); 340 return 1; 341 } 342 343 __setup("ubd", ubd_setup); 344 __uml_help(ubd_setup, 345 "ubd<n><flags>=<filename>[(:|,)<filename2>][(:|,)<serial>]\n" 346 " This is used to associate a device with a file in the underlying\n" 347 " filesystem. When specifying two filenames, the first one is the\n" 348 " COW name and the second is the backing file name. As separator you can\n" 349 " use either a ':' or a ',': the first one allows writing things like;\n" 350 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 351 " while with a ',' the shell would not expand the 2nd '~'.\n" 352 " When using only one filename, UML will detect whether to treat it like\n" 353 " a COW file or a backing file. To override this detection, add the 'd'\n" 354 " flag:\n" 355 " ubd0d=BackingFile\n" 356 " Usually, there is a filesystem in the file, but \n" 357 " that's not required. Swap devices containing swap files can be\n" 358 " specified like this. Also, a file which doesn't contain a\n" 359 " filesystem can have its contents read in the virtual \n" 360 " machine by running 'dd' on the device. <n> must be in the range\n" 361 " 0 to 7. Appending an 'r' to the number will cause that device\n" 362 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 363 " an 's' will cause data to be written to disk on the host immediately.\n" 364 " 'c' will cause the device to be treated as being shared between multiple\n" 365 " UMLs and file locking will be turned off - this is appropriate for a\n" 366 " cluster filesystem and inappropriate at almost all other times.\n\n" 367 " 't' will disable trim/discard support on the device (enabled by default).\n\n" 368 " An optional device serial number can be exposed using the serial parameter\n" 369 " on the cmdline which is exposed as a sysfs entry. This is particularly\n" 370 " useful when a unique number should be given to the device. Note when\n" 371 " specifying a label, the filename2 must be also presented. It can be\n" 372 " an empty string, in which case the backing file is not used:\n" 373 " ubd0=File,,Serial\n" 374 ); 375 376 static int udb_setup(char *str) 377 { 378 printk("udb%s specified on command line is almost certainly a ubd -> " 379 "udb TYPO\n", str); 380 return 1; 381 } 382 383 __setup("udb", udb_setup); 384 __uml_help(udb_setup, 385 "udb\n" 386 " This option is here solely to catch ubd -> udb typos, which can be\n" 387 " to impossible to catch visually unless you specifically look for\n" 388 " them. The only result of any option starting with 'udb' is an error\n" 389 " in the boot output.\n\n" 390 ); 391 392 /* Only changed by ubd_init, which is an initcall. */ 393 static int thread_fd = -1; 394 395 /* Function to read several request pointers at a time 396 * handling fractional reads if (and as) needed 397 */ 398 399 static int bulk_req_safe_read( 400 int fd, 401 struct io_thread_req * (*request_buffer)[], 402 struct io_thread_req **remainder, 403 int *remainder_size, 404 int max_recs 405 ) 406 { 407 int n = 0; 408 int res = 0; 409 410 if (*remainder_size > 0) { 411 memmove( 412 (char *) request_buffer, 413 (char *) remainder, *remainder_size 414 ); 415 n = *remainder_size; 416 } 417 418 res = os_read_file( 419 fd, 420 ((char *) request_buffer) + *remainder_size, 421 sizeof(struct io_thread_req *)*max_recs 422 - *remainder_size 423 ); 424 if (res > 0) { 425 n += res; 426 if ((n % sizeof(struct io_thread_req *)) > 0) { 427 /* 428 * Read somehow returned not a multiple of dword 429 * theoretically possible, but never observed in the 430 * wild, so read routine must be able to handle it 431 */ 432 *remainder_size = n % sizeof(struct io_thread_req *); 433 WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); 434 memmove( 435 remainder, 436 ((char *) request_buffer) + 437 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), 438 *remainder_size 439 ); 440 n = n - *remainder_size; 441 } 442 } else { 443 n = res; 444 } 445 return n; 446 } 447 448 static void ubd_end_request(struct io_thread_req *io_req) 449 { 450 if (io_req->error == BLK_STS_NOTSUPP) { 451 if (req_op(io_req->req) == REQ_OP_DISCARD) 452 blk_queue_disable_discard(io_req->req->q); 453 else if (req_op(io_req->req) == REQ_OP_WRITE_ZEROES) 454 blk_queue_disable_write_zeroes(io_req->req->q); 455 } 456 blk_mq_end_request(io_req->req, io_req->error); 457 kfree(io_req); 458 } 459 460 static irqreturn_t ubd_intr(int irq, void *dev) 461 { 462 int len, i; 463 464 while ((len = bulk_req_safe_read(thread_fd, irq_req_buffer, 465 &irq_remainder, &irq_remainder_size, 466 UBD_REQ_BUFFER_SIZE)) >= 0) { 467 for (i = 0; i < len / sizeof(struct io_thread_req *); i++) 468 ubd_end_request((*irq_req_buffer)[i]); 469 } 470 471 if (len < 0 && len != -EAGAIN) 472 pr_err("spurious interrupt in %s, err = %d\n", __func__, len); 473 return IRQ_HANDLED; 474 } 475 476 /* Only changed by ubd_init, which is an initcall. */ 477 static int io_pid = -1; 478 479 static void kill_io_thread(void) 480 { 481 if(io_pid != -1) 482 os_kill_process(io_pid, 1); 483 } 484 485 __uml_exitcall(kill_io_thread); 486 487 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) 488 { 489 char *file; 490 int fd; 491 int err; 492 493 __u32 version; 494 __u32 align; 495 char *backing_file; 496 time64_t mtime; 497 unsigned long long size; 498 int sector_size; 499 int bitmap_offset; 500 501 if (ubd_dev->file && ubd_dev->cow.file) { 502 file = ubd_dev->cow.file; 503 504 goto out; 505 } 506 507 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); 508 if (fd < 0) 509 return fd; 510 511 err = read_cow_header(file_reader, &fd, &version, &backing_file, \ 512 &mtime, &size, §or_size, &align, &bitmap_offset); 513 os_close_file(fd); 514 515 if(err == -EINVAL) 516 file = ubd_dev->file; 517 else 518 file = backing_file; 519 520 out: 521 return os_file_size(file, size_out); 522 } 523 524 static int read_cow_bitmap(int fd, void *buf, int offset, int len) 525 { 526 int err; 527 528 err = os_pread_file(fd, buf, len, offset); 529 if (err < 0) 530 return err; 531 532 return 0; 533 } 534 535 static int backing_file_mismatch(char *file, __u64 size, time64_t mtime) 536 { 537 time64_t modtime; 538 unsigned long long actual; 539 int err; 540 541 err = os_file_modtime(file, &modtime); 542 if (err < 0) { 543 printk(KERN_ERR "Failed to get modification time of backing " 544 "file \"%s\", err = %d\n", file, -err); 545 return err; 546 } 547 548 err = os_file_size(file, &actual); 549 if (err < 0) { 550 printk(KERN_ERR "Failed to get size of backing file \"%s\", " 551 "err = %d\n", file, -err); 552 return err; 553 } 554 555 if (actual != size) { 556 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 557 * the typecast.*/ 558 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " 559 "vs backing file\n", (unsigned long long) size, actual); 560 return -EINVAL; 561 } 562 if (modtime != mtime) { 563 printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs " 564 "backing file\n", mtime, modtime); 565 return -EINVAL; 566 } 567 return 0; 568 } 569 570 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) 571 { 572 struct uml_stat buf1, buf2; 573 int err; 574 575 if (from_cmdline == NULL) 576 return 0; 577 if (!strcmp(from_cmdline, from_cow)) 578 return 0; 579 580 err = os_stat_file(from_cmdline, &buf1); 581 if (err < 0) { 582 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, 583 -err); 584 return 0; 585 } 586 err = os_stat_file(from_cow, &buf2); 587 if (err < 0) { 588 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow, 589 -err); 590 return 1; 591 } 592 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 593 return 0; 594 595 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, " 596 "\"%s\" specified in COW header of \"%s\"\n", 597 from_cmdline, from_cow, cow); 598 return 1; 599 } 600 601 static int open_ubd_file(char *file, struct openflags *openflags, int shared, 602 char **backing_file_out, int *bitmap_offset_out, 603 unsigned long *bitmap_len_out, int *data_offset_out, 604 int *create_cow_out) 605 { 606 time64_t mtime; 607 unsigned long long size; 608 __u32 version, align; 609 char *backing_file; 610 int fd, err, sectorsize, asked_switch, mode = 0644; 611 612 fd = os_open_file(file, *openflags, mode); 613 if (fd < 0) { 614 if ((fd == -ENOENT) && (create_cow_out != NULL)) 615 *create_cow_out = 1; 616 if (!openflags->w || 617 ((fd != -EROFS) && (fd != -EACCES))) 618 return fd; 619 openflags->w = 0; 620 fd = os_open_file(file, *openflags, mode); 621 if (fd < 0) 622 return fd; 623 } 624 625 if (shared) 626 printk(KERN_INFO "Not locking \"%s\" on the host\n", file); 627 else { 628 err = os_lock_file(fd, openflags->w); 629 if (err < 0) { 630 printk(KERN_ERR "Failed to lock '%s', err = %d\n", 631 file, -err); 632 goto out_close; 633 } 634 } 635 636 /* Successful return case! */ 637 if (backing_file_out == NULL) 638 return fd; 639 640 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 641 &size, §orsize, &align, bitmap_offset_out); 642 if (err && (*backing_file_out != NULL)) { 643 printk(KERN_ERR "Failed to read COW header from COW file " 644 "\"%s\", errno = %d\n", file, -err); 645 goto out_close; 646 } 647 if (err) 648 return fd; 649 650 asked_switch = path_requires_switch(*backing_file_out, backing_file, 651 file); 652 653 /* Allow switching only if no mismatch. */ 654 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, 655 mtime)) { 656 printk(KERN_ERR "Switching backing file to '%s'\n", 657 *backing_file_out); 658 err = write_cow_header(file, fd, *backing_file_out, 659 sectorsize, align, &size); 660 if (err) { 661 printk(KERN_ERR "Switch failed, errno = %d\n", -err); 662 goto out_close; 663 } 664 } else { 665 *backing_file_out = backing_file; 666 err = backing_file_mismatch(*backing_file_out, size, mtime); 667 if (err) 668 goto out_close; 669 } 670 671 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 672 bitmap_len_out, data_offset_out); 673 674 return fd; 675 out_close: 676 os_close_file(fd); 677 return err; 678 } 679 680 static int create_cow_file(char *cow_file, char *backing_file, 681 struct openflags flags, 682 int sectorsize, int alignment, int *bitmap_offset_out, 683 unsigned long *bitmap_len_out, int *data_offset_out) 684 { 685 int err, fd; 686 687 flags.c = 1; 688 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); 689 if (fd < 0) { 690 err = fd; 691 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n", 692 cow_file, -err); 693 goto out; 694 } 695 696 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 697 bitmap_offset_out, bitmap_len_out, 698 data_offset_out); 699 if (!err) 700 return fd; 701 os_close_file(fd); 702 out: 703 return err; 704 } 705 706 static void ubd_close_dev(struct ubd *ubd_dev) 707 { 708 os_close_file(ubd_dev->fd); 709 if(ubd_dev->cow.file == NULL) 710 return; 711 712 os_close_file(ubd_dev->cow.fd); 713 vfree(ubd_dev->cow.bitmap); 714 ubd_dev->cow.bitmap = NULL; 715 } 716 717 static int ubd_open_dev(struct ubd *ubd_dev) 718 { 719 struct openflags flags; 720 char **back_ptr; 721 int err, create_cow, *create_ptr; 722 int fd; 723 724 ubd_dev->openflags = ubd_dev->boot_openflags; 725 create_cow = 0; 726 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; 727 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; 728 729 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, 730 back_ptr, &ubd_dev->cow.bitmap_offset, 731 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, 732 create_ptr); 733 734 if((fd == -ENOENT) && create_cow){ 735 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, 736 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE, 737 &ubd_dev->cow.bitmap_offset, 738 &ubd_dev->cow.bitmap_len, 739 &ubd_dev->cow.data_offset); 740 if(fd >= 0){ 741 printk(KERN_INFO "Creating \"%s\" as COW file for " 742 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); 743 } 744 } 745 746 if(fd < 0){ 747 printk("Failed to open '%s', errno = %d\n", ubd_dev->file, 748 -fd); 749 return fd; 750 } 751 ubd_dev->fd = fd; 752 753 if(ubd_dev->cow.file != NULL){ 754 err = -ENOMEM; 755 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len); 756 if(ubd_dev->cow.bitmap == NULL){ 757 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 758 goto error; 759 } 760 761 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, 762 ubd_dev->cow.bitmap_offset, 763 ubd_dev->cow.bitmap_len); 764 if(err < 0) 765 goto error; 766 767 flags = ubd_dev->openflags; 768 flags.w = 0; 769 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, 770 NULL, NULL, NULL, NULL); 771 if(err < 0) goto error; 772 ubd_dev->cow.fd = err; 773 } 774 return 0; 775 error: 776 os_close_file(ubd_dev->fd); 777 return err; 778 } 779 780 static void ubd_device_release(struct device *dev) 781 { 782 struct ubd *ubd_dev = container_of(dev, struct ubd, pdev.dev); 783 784 blk_mq_free_tag_set(&ubd_dev->tag_set); 785 *ubd_dev = ((struct ubd) DEFAULT_UBD); 786 } 787 788 static ssize_t serial_show(struct device *dev, 789 struct device_attribute *attr, char *buf) 790 { 791 struct gendisk *disk = dev_to_disk(dev); 792 struct ubd *ubd_dev = disk->private_data; 793 794 if (!ubd_dev) 795 return 0; 796 797 return sprintf(buf, "%s", ubd_dev->serial); 798 } 799 800 static DEVICE_ATTR_RO(serial); 801 802 static struct attribute *ubd_attrs[] = { 803 &dev_attr_serial.attr, 804 NULL, 805 }; 806 807 static umode_t ubd_attrs_are_visible(struct kobject *kobj, 808 struct attribute *a, int n) 809 { 810 return a->mode; 811 } 812 813 static const struct attribute_group ubd_attr_group = { 814 .attrs = ubd_attrs, 815 .is_visible = ubd_attrs_are_visible, 816 }; 817 818 static const struct attribute_group *ubd_attr_groups[] = { 819 &ubd_attr_group, 820 NULL, 821 }; 822 823 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE)) 824 825 static const struct blk_mq_ops ubd_mq_ops = { 826 .queue_rq = ubd_queue_rq, 827 }; 828 829 static int ubd_add(int n, char **error_out) 830 { 831 struct ubd *ubd_dev = &ubd_devs[n]; 832 struct queue_limits lim = { 833 .max_segments = MAX_SG, 834 .seg_boundary_mask = PAGE_SIZE - 1, 835 .features = BLK_FEAT_WRITE_CACHE, 836 }; 837 struct gendisk *disk; 838 int err = 0; 839 840 if(ubd_dev->file == NULL) 841 goto out; 842 843 if (ubd_dev->cow.file) 844 lim.max_hw_sectors = 8 * sizeof(long); 845 if (!ubd_dev->no_trim) { 846 lim.max_hw_discard_sectors = UBD_MAX_REQUEST; 847 lim.max_write_zeroes_sectors = UBD_MAX_REQUEST; 848 } 849 850 err = ubd_file_size(ubd_dev, &ubd_dev->size); 851 if(err < 0){ 852 *error_out = "Couldn't determine size of device's file"; 853 goto out; 854 } 855 856 err = ubd_open_dev(ubd_dev); 857 if (err) { 858 pr_err("ubd%c: Can't open \"%s\": errno = %d\n", 859 'a' + n, ubd_dev->file, -err); 860 goto out; 861 } 862 863 ubd_dev->size = ROUND_BLOCK(ubd_dev->size); 864 865 ubd_dev->tag_set.ops = &ubd_mq_ops; 866 ubd_dev->tag_set.queue_depth = 64; 867 ubd_dev->tag_set.numa_node = NUMA_NO_NODE; 868 ubd_dev->tag_set.driver_data = ubd_dev; 869 ubd_dev->tag_set.nr_hw_queues = 1; 870 871 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set); 872 if (err) 873 goto out_close; 874 875 disk = blk_mq_alloc_disk(&ubd_dev->tag_set, &lim, ubd_dev); 876 if (IS_ERR(disk)) { 877 err = PTR_ERR(disk); 878 goto out_cleanup_tags; 879 } 880 881 disk->major = UBD_MAJOR; 882 disk->first_minor = n << UBD_SHIFT; 883 disk->minors = 1 << UBD_SHIFT; 884 disk->fops = &ubd_blops; 885 set_capacity(disk, ubd_dev->size / 512); 886 sprintf(disk->disk_name, "ubd%c", 'a' + n); 887 disk->private_data = ubd_dev; 888 set_disk_ro(disk, !ubd_dev->openflags.w); 889 890 ubd_dev->pdev.id = n; 891 ubd_dev->pdev.name = DRIVER_NAME; 892 ubd_dev->pdev.dev.release = ubd_device_release; 893 dev_set_drvdata(&ubd_dev->pdev.dev, ubd_dev); 894 platform_device_register(&ubd_dev->pdev); 895 896 err = device_add_disk(&ubd_dev->pdev.dev, disk, ubd_attr_groups); 897 if (err) 898 goto out_cleanup_disk; 899 900 ubd_dev->disk = disk; 901 902 return 0; 903 904 out_cleanup_disk: 905 put_disk(disk); 906 out_cleanup_tags: 907 blk_mq_free_tag_set(&ubd_dev->tag_set); 908 out_close: 909 ubd_close_dev(ubd_dev); 910 out: 911 return err; 912 } 913 914 static int ubd_config(char *str, char **error_out) 915 { 916 int n, ret; 917 918 /* This string is possibly broken up and stored, so it's only 919 * freed if ubd_setup_common fails, or if only general options 920 * were set. 921 */ 922 str = kstrdup(str, GFP_KERNEL); 923 if (str == NULL) { 924 *error_out = "Failed to allocate memory"; 925 return -ENOMEM; 926 } 927 928 ret = ubd_setup_common(str, &n, error_out); 929 if (ret) 930 goto err_free; 931 932 if (n == -1) { 933 ret = 0; 934 goto err_free; 935 } 936 937 mutex_lock(&ubd_lock); 938 ret = ubd_add(n, error_out); 939 if (ret) 940 ubd_devs[n].file = NULL; 941 mutex_unlock(&ubd_lock); 942 943 out: 944 return ret; 945 946 err_free: 947 kfree(str); 948 goto out; 949 } 950 951 static int ubd_get_config(char *name, char *str, int size, char **error_out) 952 { 953 struct ubd *ubd_dev; 954 int n, len = 0; 955 956 n = parse_unit(&name); 957 if((n >= MAX_DEV) || (n < 0)){ 958 *error_out = "ubd_get_config : device number out of range"; 959 return -1; 960 } 961 962 ubd_dev = &ubd_devs[n]; 963 mutex_lock(&ubd_lock); 964 965 if(ubd_dev->file == NULL){ 966 CONFIG_CHUNK(str, size, len, "", 1); 967 goto out; 968 } 969 970 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); 971 972 if(ubd_dev->cow.file != NULL){ 973 CONFIG_CHUNK(str, size, len, ",", 0); 974 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); 975 } 976 else CONFIG_CHUNK(str, size, len, "", 1); 977 978 out: 979 mutex_unlock(&ubd_lock); 980 return len; 981 } 982 983 static int ubd_id(char **str, int *start_out, int *end_out) 984 { 985 int n; 986 987 n = parse_unit(str); 988 *start_out = 0; 989 *end_out = MAX_DEV - 1; 990 return n; 991 } 992 993 static int ubd_remove(int n, char **error_out) 994 { 995 struct ubd *ubd_dev; 996 int err = -ENODEV; 997 998 mutex_lock(&ubd_lock); 999 1000 ubd_dev = &ubd_devs[n]; 1001 1002 if(ubd_dev->file == NULL) 1003 goto out; 1004 1005 if (ubd_dev->disk) { 1006 /* you cannot remove a open disk */ 1007 err = -EBUSY; 1008 if (disk_openers(ubd_dev->disk)) 1009 goto out; 1010 1011 del_gendisk(ubd_dev->disk); 1012 ubd_close_dev(ubd_dev); 1013 put_disk(ubd_dev->disk); 1014 } 1015 1016 err = 0; 1017 platform_device_unregister(&ubd_dev->pdev); 1018 out: 1019 mutex_unlock(&ubd_lock); 1020 return err; 1021 } 1022 1023 /* All these are called by mconsole in process context and without 1024 * ubd-specific locks. The structure itself is const except for .list. 1025 */ 1026 static struct mc_device ubd_mc = { 1027 .list = LIST_HEAD_INIT(ubd_mc.list), 1028 .name = "ubd", 1029 .config = ubd_config, 1030 .get_config = ubd_get_config, 1031 .id = ubd_id, 1032 .remove = ubd_remove, 1033 }; 1034 1035 static int __init ubd_mc_init(void) 1036 { 1037 mconsole_register_dev(&ubd_mc); 1038 return 0; 1039 } 1040 1041 __initcall(ubd_mc_init); 1042 1043 static int __init ubd0_init(void) 1044 { 1045 struct ubd *ubd_dev = &ubd_devs[0]; 1046 1047 mutex_lock(&ubd_lock); 1048 if(ubd_dev->file == NULL) 1049 ubd_dev->file = "root_fs"; 1050 mutex_unlock(&ubd_lock); 1051 1052 return 0; 1053 } 1054 1055 __initcall(ubd0_init); 1056 1057 /* Used in ubd_init, which is an initcall */ 1058 static struct platform_driver ubd_driver = { 1059 .driver = { 1060 .name = DRIVER_NAME, 1061 }, 1062 }; 1063 1064 static int __init ubd_init(void) 1065 { 1066 char *error; 1067 int i, err; 1068 1069 if (register_blkdev(UBD_MAJOR, "ubd")) 1070 return -1; 1071 1072 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1073 sizeof(struct io_thread_req *), 1074 GFP_KERNEL 1075 ); 1076 irq_remainder = 0; 1077 1078 if (irq_req_buffer == NULL) { 1079 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1080 return -ENOMEM; 1081 } 1082 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1083 sizeof(struct io_thread_req *), 1084 GFP_KERNEL 1085 ); 1086 1087 io_remainder = 0; 1088 1089 if (io_req_buffer == NULL) { 1090 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1091 return -ENOMEM; 1092 } 1093 platform_driver_register(&ubd_driver); 1094 mutex_lock(&ubd_lock); 1095 for (i = 0; i < MAX_DEV; i++){ 1096 err = ubd_add(i, &error); 1097 if(err) 1098 printk(KERN_ERR "Failed to initialize ubd device %d :" 1099 "%s\n", i, error); 1100 } 1101 mutex_unlock(&ubd_lock); 1102 return 0; 1103 } 1104 1105 late_initcall(ubd_init); 1106 1107 static int __init ubd_driver_init(void){ 1108 unsigned long stack; 1109 int err; 1110 1111 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 1112 if(global_openflags.s){ 1113 printk(KERN_INFO "ubd: Synchronous mode\n"); 1114 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 1115 * enough. So use anyway the io thread. */ 1116 } 1117 stack = alloc_stack(0, 0); 1118 io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd); 1119 if(io_pid < 0){ 1120 printk(KERN_ERR 1121 "ubd : Failed to start I/O thread (errno = %d) - " 1122 "falling back to synchronous I/O\n", -io_pid); 1123 io_pid = -1; 1124 return 0; 1125 } 1126 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 1127 0, "ubd", ubd_devs); 1128 if(err < 0) 1129 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 1130 return 0; 1131 } 1132 1133 device_initcall(ubd_driver_init); 1134 1135 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 1136 __u64 *cow_offset, unsigned long *bitmap, 1137 __u64 bitmap_offset, unsigned long *bitmap_words, 1138 __u64 bitmap_len) 1139 { 1140 __u64 sector = io_offset >> SECTOR_SHIFT; 1141 int i, update_bitmap = 0; 1142 1143 for (i = 0; i < length >> SECTOR_SHIFT; i++) { 1144 if(cow_mask != NULL) 1145 ubd_set_bit(i, (unsigned char *) cow_mask); 1146 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1147 continue; 1148 1149 update_bitmap = 1; 1150 ubd_set_bit(sector + i, (unsigned char *) bitmap); 1151 } 1152 1153 if(!update_bitmap) 1154 return; 1155 1156 *cow_offset = sector / (sizeof(unsigned long) * 8); 1157 1158 /* This takes care of the case where we're exactly at the end of the 1159 * device, and *cow_offset + 1 is off the end. So, just back it up 1160 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 1161 * for the original diagnosis. 1162 */ 1163 if (*cow_offset == (DIV_ROUND_UP(bitmap_len, 1164 sizeof(unsigned long)) - 1)) 1165 (*cow_offset)--; 1166 1167 bitmap_words[0] = bitmap[*cow_offset]; 1168 bitmap_words[1] = bitmap[*cow_offset + 1]; 1169 1170 *cow_offset *= sizeof(unsigned long); 1171 *cow_offset += bitmap_offset; 1172 } 1173 1174 static void cowify_req(struct io_thread_req *req, struct io_desc *segment, 1175 unsigned long offset, unsigned long *bitmap, 1176 __u64 bitmap_offset, __u64 bitmap_len) 1177 { 1178 __u64 sector = offset >> SECTOR_SHIFT; 1179 int i; 1180 1181 if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT) 1182 panic("Operation too long"); 1183 1184 if (req_op(req->req) == REQ_OP_READ) { 1185 for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) { 1186 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1187 ubd_set_bit(i, (unsigned char *) 1188 &segment->sector_mask); 1189 } 1190 } else { 1191 cowify_bitmap(offset, segment->length, &segment->sector_mask, 1192 &segment->cow_offset, bitmap, bitmap_offset, 1193 segment->bitmap_words, bitmap_len); 1194 } 1195 } 1196 1197 static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req, 1198 struct request *req) 1199 { 1200 struct bio_vec bvec; 1201 struct req_iterator iter; 1202 int i = 0; 1203 unsigned long byte_offset = io_req->offset; 1204 enum req_op op = req_op(req); 1205 1206 if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) { 1207 io_req->io_desc[0].buffer = NULL; 1208 io_req->io_desc[0].length = blk_rq_bytes(req); 1209 } else { 1210 rq_for_each_segment(bvec, req, iter) { 1211 BUG_ON(i >= io_req->desc_cnt); 1212 1213 io_req->io_desc[i].buffer = bvec_virt(&bvec); 1214 io_req->io_desc[i].length = bvec.bv_len; 1215 i++; 1216 } 1217 } 1218 1219 if (dev->cow.file) { 1220 for (i = 0; i < io_req->desc_cnt; i++) { 1221 cowify_req(io_req, &io_req->io_desc[i], byte_offset, 1222 dev->cow.bitmap, dev->cow.bitmap_offset, 1223 dev->cow.bitmap_len); 1224 byte_offset += io_req->io_desc[i].length; 1225 } 1226 1227 } 1228 } 1229 1230 static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req, 1231 int desc_cnt) 1232 { 1233 struct io_thread_req *io_req; 1234 int i; 1235 1236 io_req = kmalloc(sizeof(*io_req) + 1237 (desc_cnt * sizeof(struct io_desc)), 1238 GFP_ATOMIC); 1239 if (!io_req) 1240 return NULL; 1241 1242 io_req->req = req; 1243 if (dev->cow.file) 1244 io_req->fds[0] = dev->cow.fd; 1245 else 1246 io_req->fds[0] = dev->fd; 1247 io_req->error = 0; 1248 io_req->sectorsize = SECTOR_SIZE; 1249 io_req->fds[1] = dev->fd; 1250 io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT; 1251 io_req->offsets[0] = 0; 1252 io_req->offsets[1] = dev->cow.data_offset; 1253 1254 for (i = 0 ; i < desc_cnt; i++) { 1255 io_req->io_desc[i].sector_mask = 0; 1256 io_req->io_desc[i].cow_offset = -1; 1257 } 1258 1259 return io_req; 1260 } 1261 1262 static int ubd_submit_request(struct ubd *dev, struct request *req) 1263 { 1264 int segs = 0; 1265 struct io_thread_req *io_req; 1266 int ret; 1267 enum req_op op = req_op(req); 1268 1269 if (op == REQ_OP_FLUSH) 1270 segs = 0; 1271 else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) 1272 segs = 1; 1273 else 1274 segs = blk_rq_nr_phys_segments(req); 1275 1276 io_req = ubd_alloc_req(dev, req, segs); 1277 if (!io_req) 1278 return -ENOMEM; 1279 1280 io_req->desc_cnt = segs; 1281 if (segs) 1282 ubd_map_req(dev, io_req, req); 1283 1284 ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); 1285 if (ret != sizeof(io_req)) { 1286 if (ret != -EAGAIN) 1287 pr_err("write to io thread failed: %d\n", -ret); 1288 kfree(io_req); 1289 } 1290 return ret; 1291 } 1292 1293 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 1294 const struct blk_mq_queue_data *bd) 1295 { 1296 struct ubd *ubd_dev = hctx->queue->queuedata; 1297 struct request *req = bd->rq; 1298 int ret = 0, res = BLK_STS_OK; 1299 1300 blk_mq_start_request(req); 1301 1302 spin_lock_irq(&ubd_dev->lock); 1303 1304 switch (req_op(req)) { 1305 case REQ_OP_FLUSH: 1306 case REQ_OP_READ: 1307 case REQ_OP_WRITE: 1308 case REQ_OP_DISCARD: 1309 case REQ_OP_WRITE_ZEROES: 1310 ret = ubd_submit_request(ubd_dev, req); 1311 break; 1312 default: 1313 WARN_ON_ONCE(1); 1314 res = BLK_STS_NOTSUPP; 1315 } 1316 1317 spin_unlock_irq(&ubd_dev->lock); 1318 1319 if (ret < 0) { 1320 if (ret == -ENOMEM) 1321 res = BLK_STS_RESOURCE; 1322 else 1323 res = BLK_STS_DEV_RESOURCE; 1324 } 1325 1326 return res; 1327 } 1328 1329 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) 1330 { 1331 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1332 1333 geo->heads = 128; 1334 geo->sectors = 32; 1335 geo->cylinders = ubd_dev->size / (128 * 32 * 512); 1336 return 0; 1337 } 1338 1339 static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode, 1340 unsigned int cmd, unsigned long arg) 1341 { 1342 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1343 u16 ubd_id[ATA_ID_WORDS]; 1344 1345 switch (cmd) { 1346 struct cdrom_volctrl volume; 1347 case HDIO_GET_IDENTITY: 1348 memset(&ubd_id, 0, ATA_ID_WORDS * 2); 1349 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); 1350 ubd_id[ATA_ID_HEADS] = 128; 1351 ubd_id[ATA_ID_SECTORS] = 32; 1352 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1353 sizeof(ubd_id))) 1354 return -EFAULT; 1355 return 0; 1356 1357 case CDROMVOLREAD: 1358 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1359 return -EFAULT; 1360 volume.channel0 = 255; 1361 volume.channel1 = 255; 1362 volume.channel2 = 255; 1363 volume.channel3 = 255; 1364 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1365 return -EFAULT; 1366 return 0; 1367 } 1368 return -EINVAL; 1369 } 1370 1371 static int map_error(int error_code) 1372 { 1373 switch (error_code) { 1374 case 0: 1375 return BLK_STS_OK; 1376 case ENOSYS: 1377 case EOPNOTSUPP: 1378 return BLK_STS_NOTSUPP; 1379 case ENOSPC: 1380 return BLK_STS_NOSPC; 1381 } 1382 return BLK_STS_IOERR; 1383 } 1384 1385 /* 1386 * Everything from here onwards *IS NOT PART OF THE KERNEL* 1387 * 1388 * The following functions are part of UML hypervisor code. 1389 * All functions from here onwards are executed as a helper 1390 * thread and are not allowed to execute any kernel functions. 1391 * 1392 * Any communication must occur strictly via shared memory and IPC. 1393 * 1394 * Do not add printks, locks, kernel memory operations, etc - it 1395 * will result in unpredictable behaviour and/or crashes. 1396 */ 1397 1398 static int update_bitmap(struct io_thread_req *req, struct io_desc *segment) 1399 { 1400 int n; 1401 1402 if (segment->cow_offset == -1) 1403 return map_error(0); 1404 1405 n = os_pwrite_file(req->fds[1], &segment->bitmap_words, 1406 sizeof(segment->bitmap_words), segment->cow_offset); 1407 if (n != sizeof(segment->bitmap_words)) 1408 return map_error(-n); 1409 1410 return map_error(0); 1411 } 1412 1413 static void do_io(struct io_thread_req *req, struct io_desc *desc) 1414 { 1415 char *buf = NULL; 1416 unsigned long len; 1417 int n, nsectors, start, end, bit; 1418 __u64 off; 1419 1420 /* FLUSH is really a special case, we cannot "case" it with others */ 1421 1422 if (req_op(req->req) == REQ_OP_FLUSH) { 1423 /* fds[0] is always either the rw image or our cow file */ 1424 req->error = map_error(-os_sync_file(req->fds[0])); 1425 return; 1426 } 1427 1428 nsectors = desc->length / req->sectorsize; 1429 start = 0; 1430 do { 1431 bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask); 1432 end = start; 1433 while((end < nsectors) && 1434 (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit)) 1435 end++; 1436 1437 off = req->offset + req->offsets[bit] + 1438 start * req->sectorsize; 1439 len = (end - start) * req->sectorsize; 1440 if (desc->buffer != NULL) 1441 buf = &desc->buffer[start * req->sectorsize]; 1442 1443 switch (req_op(req->req)) { 1444 case REQ_OP_READ: 1445 n = 0; 1446 do { 1447 buf = &buf[n]; 1448 len -= n; 1449 n = os_pread_file(req->fds[bit], buf, len, off); 1450 if (n < 0) { 1451 req->error = map_error(-n); 1452 return; 1453 } 1454 } while((n < len) && (n != 0)); 1455 if (n < len) memset(&buf[n], 0, len - n); 1456 break; 1457 case REQ_OP_WRITE: 1458 n = os_pwrite_file(req->fds[bit], buf, len, off); 1459 if(n != len){ 1460 req->error = map_error(-n); 1461 return; 1462 } 1463 break; 1464 case REQ_OP_DISCARD: 1465 n = os_falloc_punch(req->fds[bit], off, len); 1466 if (n) { 1467 req->error = map_error(-n); 1468 return; 1469 } 1470 break; 1471 case REQ_OP_WRITE_ZEROES: 1472 n = os_falloc_zeroes(req->fds[bit], off, len); 1473 if (n) { 1474 req->error = map_error(-n); 1475 return; 1476 } 1477 break; 1478 default: 1479 WARN_ON_ONCE(1); 1480 req->error = BLK_STS_NOTSUPP; 1481 return; 1482 } 1483 1484 start = end; 1485 } while(start < nsectors); 1486 1487 req->offset += len; 1488 req->error = update_bitmap(req, desc); 1489 } 1490 1491 /* Changed in start_io_thread, which is serialized by being called only 1492 * from ubd_init, which is an initcall. 1493 */ 1494 int kernel_fd = -1; 1495 1496 /* Only changed by the io thread. XXX: currently unused. */ 1497 static int io_count; 1498 1499 int io_thread(void *arg) 1500 { 1501 int n, count, written, res; 1502 1503 os_set_pdeathsig(); 1504 os_fix_helper_signals(); 1505 1506 while(1){ 1507 n = bulk_req_safe_read( 1508 kernel_fd, 1509 io_req_buffer, 1510 &io_remainder, 1511 &io_remainder_size, 1512 UBD_REQ_BUFFER_SIZE 1513 ); 1514 if (n <= 0) { 1515 if (n == -EAGAIN) 1516 ubd_read_poll(-1); 1517 1518 continue; 1519 } 1520 1521 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 1522 struct io_thread_req *req = (*io_req_buffer)[count]; 1523 int i; 1524 1525 io_count++; 1526 for (i = 0; !req->error && i < req->desc_cnt; i++) 1527 do_io(req, &(req->io_desc[i])); 1528 1529 } 1530 1531 written = 0; 1532 1533 do { 1534 res = os_write_file(kernel_fd, 1535 ((char *) io_req_buffer) + written, 1536 n - written); 1537 if (res >= 0) { 1538 written += res; 1539 } 1540 if (written < n) { 1541 ubd_write_poll(-1); 1542 } 1543 } while (written < n); 1544 } 1545 1546 return 0; 1547 } 1548