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/cdrom.h> 31 #include <linux/proc_fs.h> 32 #include <linux/seq_file.h> 33 #include <linux/ctype.h> 34 #include <linux/slab.h> 35 #include <linux/vmalloc.h> 36 #include <linux/platform_device.h> 37 #include <linux/scatterlist.h> 38 #include <asm/tlbflush.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 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */ 109 110 static int ubd_open(struct block_device *bdev, fmode_t mode); 111 static void ubd_release(struct gendisk *disk, fmode_t mode); 112 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 113 unsigned int cmd, unsigned long arg); 114 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); 115 116 #define MAX_DEV (16) 117 118 static const struct block_device_operations ubd_blops = { 119 .owner = THIS_MODULE, 120 .open = ubd_open, 121 .release = ubd_release, 122 .ioctl = ubd_ioctl, 123 .compat_ioctl = blkdev_compat_ptr_ioctl, 124 .getgeo = ubd_getgeo, 125 }; 126 127 /* Protected by ubd_lock */ 128 static struct gendisk *ubd_gendisk[MAX_DEV]; 129 130 #ifdef CONFIG_BLK_DEV_UBD_SYNC 131 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 132 .cl = 1 }) 133 #else 134 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 135 .cl = 1 }) 136 #endif 137 static struct openflags global_openflags = OPEN_FLAGS; 138 139 struct cow { 140 /* backing file name */ 141 char *file; 142 /* backing file fd */ 143 int fd; 144 unsigned long *bitmap; 145 unsigned long bitmap_len; 146 int bitmap_offset; 147 int data_offset; 148 }; 149 150 #define MAX_SG 64 151 152 struct ubd { 153 /* name (and fd, below) of the file opened for writing, either the 154 * backing or the cow file. */ 155 char *file; 156 char *serial; 157 int count; 158 int fd; 159 __u64 size; 160 struct openflags boot_openflags; 161 struct openflags openflags; 162 unsigned shared:1; 163 unsigned no_cow:1; 164 unsigned no_trim:1; 165 struct cow cow; 166 struct platform_device pdev; 167 struct request_queue *queue; 168 struct blk_mq_tag_set tag_set; 169 spinlock_t lock; 170 }; 171 172 #define DEFAULT_COW { \ 173 .file = NULL, \ 174 .fd = -1, \ 175 .bitmap = NULL, \ 176 .bitmap_offset = 0, \ 177 .data_offset = 0, \ 178 } 179 180 #define DEFAULT_UBD { \ 181 .file = NULL, \ 182 .serial = NULL, \ 183 .count = 0, \ 184 .fd = -1, \ 185 .size = -1, \ 186 .boot_openflags = OPEN_FLAGS, \ 187 .openflags = OPEN_FLAGS, \ 188 .no_cow = 0, \ 189 .no_trim = 0, \ 190 .shared = 0, \ 191 .cow = DEFAULT_COW, \ 192 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \ 193 } 194 195 /* Protected by ubd_lock */ 196 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD }; 197 198 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 199 const struct blk_mq_queue_data *bd); 200 201 static int fake_ide_setup(char *str) 202 { 203 pr_warn("The fake_ide option has been removed\n"); 204 return 1; 205 } 206 __setup("fake_ide", fake_ide_setup); 207 208 __uml_help(fake_ide_setup, 209 "fake_ide\n" 210 " Obsolete stub.\n\n" 211 ); 212 213 static int parse_unit(char **ptr) 214 { 215 char *str = *ptr, *end; 216 int n = -1; 217 218 if(isdigit(*str)) { 219 n = simple_strtoul(str, &end, 0); 220 if(end == str) 221 return -1; 222 *ptr = end; 223 } 224 else if (('a' <= *str) && (*str <= 'z')) { 225 n = *str - 'a'; 226 str++; 227 *ptr = str; 228 } 229 return n; 230 } 231 232 /* If *index_out == -1 at exit, the passed option was a general one; 233 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it 234 * should not be freed on exit. 235 */ 236 static int ubd_setup_common(char *str, int *index_out, char **error_out) 237 { 238 struct ubd *ubd_dev; 239 struct openflags flags = global_openflags; 240 char *file, *backing_file, *serial; 241 int n, err = 0, i; 242 243 if(index_out) *index_out = -1; 244 n = *str; 245 if(n == '='){ 246 str++; 247 if(!strcmp(str, "sync")){ 248 global_openflags = of_sync(global_openflags); 249 return err; 250 } 251 252 pr_warn("fake major not supported any more\n"); 253 return 0; 254 } 255 256 n = parse_unit(&str); 257 if(n < 0){ 258 *error_out = "Couldn't parse device number"; 259 return -EINVAL; 260 } 261 if(n >= MAX_DEV){ 262 *error_out = "Device number out of range"; 263 return 1; 264 } 265 266 err = -EBUSY; 267 mutex_lock(&ubd_lock); 268 269 ubd_dev = &ubd_devs[n]; 270 if(ubd_dev->file != NULL){ 271 *error_out = "Device is already configured"; 272 goto out; 273 } 274 275 if (index_out) 276 *index_out = n; 277 278 err = -EINVAL; 279 for (i = 0; i < sizeof("rscdt="); i++) { 280 switch (*str) { 281 case 'r': 282 flags.w = 0; 283 break; 284 case 's': 285 flags.s = 1; 286 break; 287 case 'd': 288 ubd_dev->no_cow = 1; 289 break; 290 case 'c': 291 ubd_dev->shared = 1; 292 break; 293 case 't': 294 ubd_dev->no_trim = 1; 295 break; 296 case '=': 297 str++; 298 goto break_loop; 299 default: 300 *error_out = "Expected '=' or flag letter " 301 "(r, s, c, t or d)"; 302 goto out; 303 } 304 str++; 305 } 306 307 if (*str == '=') 308 *error_out = "Too many flags specified"; 309 else 310 *error_out = "Missing '='"; 311 goto out; 312 313 break_loop: 314 file = strsep(&str, ",:"); 315 if (*file == '\0') 316 file = NULL; 317 318 backing_file = strsep(&str, ",:"); 319 if (backing_file && *backing_file == '\0') 320 backing_file = NULL; 321 322 serial = strsep(&str, ",:"); 323 if (serial && *serial == '\0') 324 serial = NULL; 325 326 if (backing_file && ubd_dev->no_cow) { 327 *error_out = "Can't specify both 'd' and a cow file"; 328 goto out; 329 } 330 331 err = 0; 332 ubd_dev->file = file; 333 ubd_dev->cow.file = backing_file; 334 ubd_dev->serial = serial; 335 ubd_dev->boot_openflags = flags; 336 out: 337 mutex_unlock(&ubd_lock); 338 return err; 339 } 340 341 static int ubd_setup(char *str) 342 { 343 char *error; 344 int err; 345 346 err = ubd_setup_common(str, NULL, &error); 347 if(err) 348 printk(KERN_ERR "Failed to initialize device with \"%s\" : " 349 "%s\n", str, error); 350 return 1; 351 } 352 353 __setup("ubd", ubd_setup); 354 __uml_help(ubd_setup, 355 "ubd<n><flags>=<filename>[(:|,)<filename2>][(:|,)<serial>]\n" 356 " This is used to associate a device with a file in the underlying\n" 357 " filesystem. When specifying two filenames, the first one is the\n" 358 " COW name and the second is the backing file name. As separator you can\n" 359 " use either a ':' or a ',': the first one allows writing things like;\n" 360 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 361 " while with a ',' the shell would not expand the 2nd '~'.\n" 362 " When using only one filename, UML will detect whether to treat it like\n" 363 " a COW file or a backing file. To override this detection, add the 'd'\n" 364 " flag:\n" 365 " ubd0d=BackingFile\n" 366 " Usually, there is a filesystem in the file, but \n" 367 " that's not required. Swap devices containing swap files can be\n" 368 " specified like this. Also, a file which doesn't contain a\n" 369 " filesystem can have its contents read in the virtual \n" 370 " machine by running 'dd' on the device. <n> must be in the range\n" 371 " 0 to 7. Appending an 'r' to the number will cause that device\n" 372 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 373 " an 's' will cause data to be written to disk on the host immediately.\n" 374 " 'c' will cause the device to be treated as being shared between multiple\n" 375 " UMLs and file locking will be turned off - this is appropriate for a\n" 376 " cluster filesystem and inappropriate at almost all other times.\n\n" 377 " 't' will disable trim/discard support on the device (enabled by default).\n\n" 378 " An optional device serial number can be exposed using the serial parameter\n" 379 " on the cmdline which is exposed as a sysfs entry. This is particularly\n" 380 " useful when a unique number should be given to the device. Note when\n" 381 " specifying a label, the filename2 must be also presented. It can be\n" 382 " an empty string, in which case the backing file is not used:\n" 383 " ubd0=File,,Serial\n" 384 ); 385 386 static int udb_setup(char *str) 387 { 388 printk("udb%s specified on command line is almost certainly a ubd -> " 389 "udb TYPO\n", str); 390 return 1; 391 } 392 393 __setup("udb", udb_setup); 394 __uml_help(udb_setup, 395 "udb\n" 396 " This option is here solely to catch ubd -> udb typos, which can be\n" 397 " to impossible to catch visually unless you specifically look for\n" 398 " them. The only result of any option starting with 'udb' is an error\n" 399 " in the boot output.\n\n" 400 ); 401 402 /* Only changed by ubd_init, which is an initcall. */ 403 static int thread_fd = -1; 404 405 /* Function to read several request pointers at a time 406 * handling fractional reads if (and as) needed 407 */ 408 409 static int bulk_req_safe_read( 410 int fd, 411 struct io_thread_req * (*request_buffer)[], 412 struct io_thread_req **remainder, 413 int *remainder_size, 414 int max_recs 415 ) 416 { 417 int n = 0; 418 int res = 0; 419 420 if (*remainder_size > 0) { 421 memmove( 422 (char *) request_buffer, 423 (char *) remainder, *remainder_size 424 ); 425 n = *remainder_size; 426 } 427 428 res = os_read_file( 429 fd, 430 ((char *) request_buffer) + *remainder_size, 431 sizeof(struct io_thread_req *)*max_recs 432 - *remainder_size 433 ); 434 if (res > 0) { 435 n += res; 436 if ((n % sizeof(struct io_thread_req *)) > 0) { 437 /* 438 * Read somehow returned not a multiple of dword 439 * theoretically possible, but never observed in the 440 * wild, so read routine must be able to handle it 441 */ 442 *remainder_size = n % sizeof(struct io_thread_req *); 443 WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); 444 memmove( 445 remainder, 446 ((char *) request_buffer) + 447 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), 448 *remainder_size 449 ); 450 n = n - *remainder_size; 451 } 452 } else { 453 n = res; 454 } 455 return n; 456 } 457 458 /* Called without dev->lock held, and only in interrupt context. */ 459 static void ubd_handler(void) 460 { 461 int n; 462 int count; 463 464 while(1){ 465 n = bulk_req_safe_read( 466 thread_fd, 467 irq_req_buffer, 468 &irq_remainder, 469 &irq_remainder_size, 470 UBD_REQ_BUFFER_SIZE 471 ); 472 if (n < 0) { 473 if(n == -EAGAIN) 474 break; 475 printk(KERN_ERR "spurious interrupt in ubd_handler, " 476 "err = %d\n", -n); 477 return; 478 } 479 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 480 struct io_thread_req *io_req = (*irq_req_buffer)[count]; 481 482 if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) { 483 blk_queue_max_discard_sectors(io_req->req->q, 0); 484 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0); 485 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q); 486 } 487 blk_mq_end_request(io_req->req, io_req->error); 488 kfree(io_req); 489 } 490 } 491 } 492 493 static irqreturn_t ubd_intr(int irq, void *dev) 494 { 495 ubd_handler(); 496 return IRQ_HANDLED; 497 } 498 499 /* Only changed by ubd_init, which is an initcall. */ 500 static int io_pid = -1; 501 502 static void kill_io_thread(void) 503 { 504 if(io_pid != -1) 505 os_kill_process(io_pid, 1); 506 } 507 508 __uml_exitcall(kill_io_thread); 509 510 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) 511 { 512 char *file; 513 int fd; 514 int err; 515 516 __u32 version; 517 __u32 align; 518 char *backing_file; 519 time64_t mtime; 520 unsigned long long size; 521 int sector_size; 522 int bitmap_offset; 523 524 if (ubd_dev->file && ubd_dev->cow.file) { 525 file = ubd_dev->cow.file; 526 527 goto out; 528 } 529 530 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); 531 if (fd < 0) 532 return fd; 533 534 err = read_cow_header(file_reader, &fd, &version, &backing_file, \ 535 &mtime, &size, §or_size, &align, &bitmap_offset); 536 os_close_file(fd); 537 538 if(err == -EINVAL) 539 file = ubd_dev->file; 540 else 541 file = backing_file; 542 543 out: 544 return os_file_size(file, size_out); 545 } 546 547 static int read_cow_bitmap(int fd, void *buf, int offset, int len) 548 { 549 int err; 550 551 err = os_pread_file(fd, buf, len, offset); 552 if (err < 0) 553 return err; 554 555 return 0; 556 } 557 558 static int backing_file_mismatch(char *file, __u64 size, time64_t mtime) 559 { 560 time64_t modtime; 561 unsigned long long actual; 562 int err; 563 564 err = os_file_modtime(file, &modtime); 565 if (err < 0) { 566 printk(KERN_ERR "Failed to get modification time of backing " 567 "file \"%s\", err = %d\n", file, -err); 568 return err; 569 } 570 571 err = os_file_size(file, &actual); 572 if (err < 0) { 573 printk(KERN_ERR "Failed to get size of backing file \"%s\", " 574 "err = %d\n", file, -err); 575 return err; 576 } 577 578 if (actual != size) { 579 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 580 * the typecast.*/ 581 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " 582 "vs backing file\n", (unsigned long long) size, actual); 583 return -EINVAL; 584 } 585 if (modtime != mtime) { 586 printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs " 587 "backing file\n", mtime, modtime); 588 return -EINVAL; 589 } 590 return 0; 591 } 592 593 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) 594 { 595 struct uml_stat buf1, buf2; 596 int err; 597 598 if (from_cmdline == NULL) 599 return 0; 600 if (!strcmp(from_cmdline, from_cow)) 601 return 0; 602 603 err = os_stat_file(from_cmdline, &buf1); 604 if (err < 0) { 605 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, 606 -err); 607 return 0; 608 } 609 err = os_stat_file(from_cow, &buf2); 610 if (err < 0) { 611 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow, 612 -err); 613 return 1; 614 } 615 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 616 return 0; 617 618 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, " 619 "\"%s\" specified in COW header of \"%s\"\n", 620 from_cmdline, from_cow, cow); 621 return 1; 622 } 623 624 static int open_ubd_file(char *file, struct openflags *openflags, int shared, 625 char **backing_file_out, int *bitmap_offset_out, 626 unsigned long *bitmap_len_out, int *data_offset_out, 627 int *create_cow_out) 628 { 629 time64_t mtime; 630 unsigned long long size; 631 __u32 version, align; 632 char *backing_file; 633 int fd, err, sectorsize, asked_switch, mode = 0644; 634 635 fd = os_open_file(file, *openflags, mode); 636 if (fd < 0) { 637 if ((fd == -ENOENT) && (create_cow_out != NULL)) 638 *create_cow_out = 1; 639 if (!openflags->w || 640 ((fd != -EROFS) && (fd != -EACCES))) 641 return fd; 642 openflags->w = 0; 643 fd = os_open_file(file, *openflags, mode); 644 if (fd < 0) 645 return fd; 646 } 647 648 if (shared) 649 printk(KERN_INFO "Not locking \"%s\" on the host\n", file); 650 else { 651 err = os_lock_file(fd, openflags->w); 652 if (err < 0) { 653 printk(KERN_ERR "Failed to lock '%s', err = %d\n", 654 file, -err); 655 goto out_close; 656 } 657 } 658 659 /* Successful return case! */ 660 if (backing_file_out == NULL) 661 return fd; 662 663 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 664 &size, §orsize, &align, bitmap_offset_out); 665 if (err && (*backing_file_out != NULL)) { 666 printk(KERN_ERR "Failed to read COW header from COW file " 667 "\"%s\", errno = %d\n", file, -err); 668 goto out_close; 669 } 670 if (err) 671 return fd; 672 673 asked_switch = path_requires_switch(*backing_file_out, backing_file, 674 file); 675 676 /* Allow switching only if no mismatch. */ 677 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, 678 mtime)) { 679 printk(KERN_ERR "Switching backing file to '%s'\n", 680 *backing_file_out); 681 err = write_cow_header(file, fd, *backing_file_out, 682 sectorsize, align, &size); 683 if (err) { 684 printk(KERN_ERR "Switch failed, errno = %d\n", -err); 685 goto out_close; 686 } 687 } else { 688 *backing_file_out = backing_file; 689 err = backing_file_mismatch(*backing_file_out, size, mtime); 690 if (err) 691 goto out_close; 692 } 693 694 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 695 bitmap_len_out, data_offset_out); 696 697 return fd; 698 out_close: 699 os_close_file(fd); 700 return err; 701 } 702 703 static int create_cow_file(char *cow_file, char *backing_file, 704 struct openflags flags, 705 int sectorsize, int alignment, int *bitmap_offset_out, 706 unsigned long *bitmap_len_out, int *data_offset_out) 707 { 708 int err, fd; 709 710 flags.c = 1; 711 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); 712 if (fd < 0) { 713 err = fd; 714 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n", 715 cow_file, -err); 716 goto out; 717 } 718 719 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 720 bitmap_offset_out, bitmap_len_out, 721 data_offset_out); 722 if (!err) 723 return fd; 724 os_close_file(fd); 725 out: 726 return err; 727 } 728 729 static void ubd_close_dev(struct ubd *ubd_dev) 730 { 731 os_close_file(ubd_dev->fd); 732 if(ubd_dev->cow.file == NULL) 733 return; 734 735 os_close_file(ubd_dev->cow.fd); 736 vfree(ubd_dev->cow.bitmap); 737 ubd_dev->cow.bitmap = NULL; 738 } 739 740 static int ubd_open_dev(struct ubd *ubd_dev) 741 { 742 struct openflags flags; 743 char **back_ptr; 744 int err, create_cow, *create_ptr; 745 int fd; 746 747 ubd_dev->openflags = ubd_dev->boot_openflags; 748 create_cow = 0; 749 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; 750 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; 751 752 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, 753 back_ptr, &ubd_dev->cow.bitmap_offset, 754 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, 755 create_ptr); 756 757 if((fd == -ENOENT) && create_cow){ 758 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, 759 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE, 760 &ubd_dev->cow.bitmap_offset, 761 &ubd_dev->cow.bitmap_len, 762 &ubd_dev->cow.data_offset); 763 if(fd >= 0){ 764 printk(KERN_INFO "Creating \"%s\" as COW file for " 765 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); 766 } 767 } 768 769 if(fd < 0){ 770 printk("Failed to open '%s', errno = %d\n", ubd_dev->file, 771 -fd); 772 return fd; 773 } 774 ubd_dev->fd = fd; 775 776 if(ubd_dev->cow.file != NULL){ 777 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long)); 778 779 err = -ENOMEM; 780 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len); 781 if(ubd_dev->cow.bitmap == NULL){ 782 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 783 goto error; 784 } 785 flush_tlb_kernel_vm(); 786 787 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, 788 ubd_dev->cow.bitmap_offset, 789 ubd_dev->cow.bitmap_len); 790 if(err < 0) 791 goto error; 792 793 flags = ubd_dev->openflags; 794 flags.w = 0; 795 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, 796 NULL, NULL, NULL, NULL); 797 if(err < 0) goto error; 798 ubd_dev->cow.fd = err; 799 } 800 if (ubd_dev->no_trim == 0) { 801 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE; 802 ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE; 803 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST); 804 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST); 805 blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue); 806 } 807 blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue); 808 return 0; 809 error: 810 os_close_file(ubd_dev->fd); 811 return err; 812 } 813 814 static void ubd_device_release(struct device *dev) 815 { 816 struct ubd *ubd_dev = dev_get_drvdata(dev); 817 818 blk_mq_free_tag_set(&ubd_dev->tag_set); 819 *ubd_dev = ((struct ubd) DEFAULT_UBD); 820 } 821 822 static ssize_t serial_show(struct device *dev, 823 struct device_attribute *attr, char *buf) 824 { 825 struct gendisk *disk = dev_to_disk(dev); 826 struct ubd *ubd_dev = disk->private_data; 827 828 if (!ubd_dev) 829 return 0; 830 831 return sprintf(buf, "%s", ubd_dev->serial); 832 } 833 834 static DEVICE_ATTR_RO(serial); 835 836 static struct attribute *ubd_attrs[] = { 837 &dev_attr_serial.attr, 838 NULL, 839 }; 840 841 static umode_t ubd_attrs_are_visible(struct kobject *kobj, 842 struct attribute *a, int n) 843 { 844 return a->mode; 845 } 846 847 static const struct attribute_group ubd_attr_group = { 848 .attrs = ubd_attrs, 849 .is_visible = ubd_attrs_are_visible, 850 }; 851 852 static const struct attribute_group *ubd_attr_groups[] = { 853 &ubd_attr_group, 854 NULL, 855 }; 856 857 static void ubd_disk_register(int major, u64 size, int unit, 858 struct gendisk *disk) 859 { 860 disk->major = major; 861 disk->first_minor = unit << UBD_SHIFT; 862 disk->minors = 1 << UBD_SHIFT; 863 disk->fops = &ubd_blops; 864 set_capacity(disk, size / 512); 865 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 866 867 ubd_devs[unit].pdev.id = unit; 868 ubd_devs[unit].pdev.name = DRIVER_NAME; 869 ubd_devs[unit].pdev.dev.release = ubd_device_release; 870 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]); 871 platform_device_register(&ubd_devs[unit].pdev); 872 873 disk->private_data = &ubd_devs[unit]; 874 disk->queue = ubd_devs[unit].queue; 875 device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups); 876 } 877 878 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE)) 879 880 static const struct blk_mq_ops ubd_mq_ops = { 881 .queue_rq = ubd_queue_rq, 882 }; 883 884 static int ubd_add(int n, char **error_out) 885 { 886 struct ubd *ubd_dev = &ubd_devs[n]; 887 struct gendisk *disk; 888 int err = 0; 889 890 if(ubd_dev->file == NULL) 891 goto out; 892 893 err = ubd_file_size(ubd_dev, &ubd_dev->size); 894 if(err < 0){ 895 *error_out = "Couldn't determine size of device's file"; 896 goto out; 897 } 898 899 ubd_dev->size = ROUND_BLOCK(ubd_dev->size); 900 901 ubd_dev->tag_set.ops = &ubd_mq_ops; 902 ubd_dev->tag_set.queue_depth = 64; 903 ubd_dev->tag_set.numa_node = NUMA_NO_NODE; 904 ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 905 ubd_dev->tag_set.driver_data = ubd_dev; 906 ubd_dev->tag_set.nr_hw_queues = 1; 907 908 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set); 909 if (err) 910 goto out; 911 912 disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev); 913 if (IS_ERR(disk)) { 914 err = PTR_ERR(disk); 915 goto out_cleanup_tags; 916 } 917 ubd_dev->queue = disk->queue; 918 919 blk_queue_write_cache(ubd_dev->queue, true, false); 920 blk_queue_max_segments(ubd_dev->queue, MAX_SG); 921 blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1); 922 ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk); 923 ubd_gendisk[n] = disk; 924 return 0; 925 926 out_cleanup_tags: 927 blk_mq_free_tag_set(&ubd_dev->tag_set); 928 out: 929 return err; 930 } 931 932 static int ubd_config(char *str, char **error_out) 933 { 934 int n, ret; 935 936 /* This string is possibly broken up and stored, so it's only 937 * freed if ubd_setup_common fails, or if only general options 938 * were set. 939 */ 940 str = kstrdup(str, GFP_KERNEL); 941 if (str == NULL) { 942 *error_out = "Failed to allocate memory"; 943 return -ENOMEM; 944 } 945 946 ret = ubd_setup_common(str, &n, error_out); 947 if (ret) 948 goto err_free; 949 950 if (n == -1) { 951 ret = 0; 952 goto err_free; 953 } 954 955 mutex_lock(&ubd_lock); 956 ret = ubd_add(n, error_out); 957 if (ret) 958 ubd_devs[n].file = NULL; 959 mutex_unlock(&ubd_lock); 960 961 out: 962 return ret; 963 964 err_free: 965 kfree(str); 966 goto out; 967 } 968 969 static int ubd_get_config(char *name, char *str, int size, char **error_out) 970 { 971 struct ubd *ubd_dev; 972 int n, len = 0; 973 974 n = parse_unit(&name); 975 if((n >= MAX_DEV) || (n < 0)){ 976 *error_out = "ubd_get_config : device number out of range"; 977 return -1; 978 } 979 980 ubd_dev = &ubd_devs[n]; 981 mutex_lock(&ubd_lock); 982 983 if(ubd_dev->file == NULL){ 984 CONFIG_CHUNK(str, size, len, "", 1); 985 goto out; 986 } 987 988 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); 989 990 if(ubd_dev->cow.file != NULL){ 991 CONFIG_CHUNK(str, size, len, ",", 0); 992 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); 993 } 994 else CONFIG_CHUNK(str, size, len, "", 1); 995 996 out: 997 mutex_unlock(&ubd_lock); 998 return len; 999 } 1000 1001 static int ubd_id(char **str, int *start_out, int *end_out) 1002 { 1003 int n; 1004 1005 n = parse_unit(str); 1006 *start_out = 0; 1007 *end_out = MAX_DEV - 1; 1008 return n; 1009 } 1010 1011 static int ubd_remove(int n, char **error_out) 1012 { 1013 struct gendisk *disk = ubd_gendisk[n]; 1014 struct ubd *ubd_dev; 1015 int err = -ENODEV; 1016 1017 mutex_lock(&ubd_lock); 1018 1019 ubd_dev = &ubd_devs[n]; 1020 1021 if(ubd_dev->file == NULL) 1022 goto out; 1023 1024 /* you cannot remove a open disk */ 1025 err = -EBUSY; 1026 if(ubd_dev->count > 0) 1027 goto out; 1028 1029 ubd_gendisk[n] = NULL; 1030 if(disk != NULL){ 1031 del_gendisk(disk); 1032 blk_cleanup_disk(disk); 1033 } 1034 1035 err = 0; 1036 platform_device_unregister(&ubd_dev->pdev); 1037 out: 1038 mutex_unlock(&ubd_lock); 1039 return err; 1040 } 1041 1042 /* All these are called by mconsole in process context and without 1043 * ubd-specific locks. The structure itself is const except for .list. 1044 */ 1045 static struct mc_device ubd_mc = { 1046 .list = LIST_HEAD_INIT(ubd_mc.list), 1047 .name = "ubd", 1048 .config = ubd_config, 1049 .get_config = ubd_get_config, 1050 .id = ubd_id, 1051 .remove = ubd_remove, 1052 }; 1053 1054 static int __init ubd_mc_init(void) 1055 { 1056 mconsole_register_dev(&ubd_mc); 1057 return 0; 1058 } 1059 1060 __initcall(ubd_mc_init); 1061 1062 static int __init ubd0_init(void) 1063 { 1064 struct ubd *ubd_dev = &ubd_devs[0]; 1065 1066 mutex_lock(&ubd_lock); 1067 if(ubd_dev->file == NULL) 1068 ubd_dev->file = "root_fs"; 1069 mutex_unlock(&ubd_lock); 1070 1071 return 0; 1072 } 1073 1074 __initcall(ubd0_init); 1075 1076 /* Used in ubd_init, which is an initcall */ 1077 static struct platform_driver ubd_driver = { 1078 .driver = { 1079 .name = DRIVER_NAME, 1080 }, 1081 }; 1082 1083 static int __init ubd_init(void) 1084 { 1085 char *error; 1086 int i, err; 1087 1088 if (register_blkdev(UBD_MAJOR, "ubd")) 1089 return -1; 1090 1091 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1092 sizeof(struct io_thread_req *), 1093 GFP_KERNEL 1094 ); 1095 irq_remainder = 0; 1096 1097 if (irq_req_buffer == NULL) { 1098 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1099 return -1; 1100 } 1101 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1102 sizeof(struct io_thread_req *), 1103 GFP_KERNEL 1104 ); 1105 1106 io_remainder = 0; 1107 1108 if (io_req_buffer == NULL) { 1109 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1110 return -1; 1111 } 1112 platform_driver_register(&ubd_driver); 1113 mutex_lock(&ubd_lock); 1114 for (i = 0; i < MAX_DEV; i++){ 1115 err = ubd_add(i, &error); 1116 if(err) 1117 printk(KERN_ERR "Failed to initialize ubd device %d :" 1118 "%s\n", i, error); 1119 } 1120 mutex_unlock(&ubd_lock); 1121 return 0; 1122 } 1123 1124 late_initcall(ubd_init); 1125 1126 static int __init ubd_driver_init(void){ 1127 unsigned long stack; 1128 int err; 1129 1130 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 1131 if(global_openflags.s){ 1132 printk(KERN_INFO "ubd: Synchronous mode\n"); 1133 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 1134 * enough. So use anyway the io thread. */ 1135 } 1136 stack = alloc_stack(0, 0); 1137 io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd); 1138 if(io_pid < 0){ 1139 printk(KERN_ERR 1140 "ubd : Failed to start I/O thread (errno = %d) - " 1141 "falling back to synchronous I/O\n", -io_pid); 1142 io_pid = -1; 1143 return 0; 1144 } 1145 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 1146 0, "ubd", ubd_devs); 1147 if(err < 0) 1148 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 1149 return 0; 1150 } 1151 1152 device_initcall(ubd_driver_init); 1153 1154 static int ubd_open(struct block_device *bdev, fmode_t mode) 1155 { 1156 struct gendisk *disk = bdev->bd_disk; 1157 struct ubd *ubd_dev = disk->private_data; 1158 int err = 0; 1159 1160 mutex_lock(&ubd_mutex); 1161 if(ubd_dev->count == 0){ 1162 err = ubd_open_dev(ubd_dev); 1163 if(err){ 1164 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 1165 disk->disk_name, ubd_dev->file, -err); 1166 goto out; 1167 } 1168 } 1169 ubd_dev->count++; 1170 set_disk_ro(disk, !ubd_dev->openflags.w); 1171 1172 /* This should no more be needed. And it didn't work anyway to exclude 1173 * read-write remounting of filesystems.*/ 1174 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){ 1175 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); 1176 err = -EROFS; 1177 }*/ 1178 out: 1179 mutex_unlock(&ubd_mutex); 1180 return err; 1181 } 1182 1183 static void ubd_release(struct gendisk *disk, fmode_t mode) 1184 { 1185 struct ubd *ubd_dev = disk->private_data; 1186 1187 mutex_lock(&ubd_mutex); 1188 if(--ubd_dev->count == 0) 1189 ubd_close_dev(ubd_dev); 1190 mutex_unlock(&ubd_mutex); 1191 } 1192 1193 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 1194 __u64 *cow_offset, unsigned long *bitmap, 1195 __u64 bitmap_offset, unsigned long *bitmap_words, 1196 __u64 bitmap_len) 1197 { 1198 __u64 sector = io_offset >> SECTOR_SHIFT; 1199 int i, update_bitmap = 0; 1200 1201 for (i = 0; i < length >> SECTOR_SHIFT; i++) { 1202 if(cow_mask != NULL) 1203 ubd_set_bit(i, (unsigned char *) cow_mask); 1204 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1205 continue; 1206 1207 update_bitmap = 1; 1208 ubd_set_bit(sector + i, (unsigned char *) bitmap); 1209 } 1210 1211 if(!update_bitmap) 1212 return; 1213 1214 *cow_offset = sector / (sizeof(unsigned long) * 8); 1215 1216 /* This takes care of the case where we're exactly at the end of the 1217 * device, and *cow_offset + 1 is off the end. So, just back it up 1218 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 1219 * for the original diagnosis. 1220 */ 1221 if (*cow_offset == (DIV_ROUND_UP(bitmap_len, 1222 sizeof(unsigned long)) - 1)) 1223 (*cow_offset)--; 1224 1225 bitmap_words[0] = bitmap[*cow_offset]; 1226 bitmap_words[1] = bitmap[*cow_offset + 1]; 1227 1228 *cow_offset *= sizeof(unsigned long); 1229 *cow_offset += bitmap_offset; 1230 } 1231 1232 static void cowify_req(struct io_thread_req *req, struct io_desc *segment, 1233 unsigned long offset, unsigned long *bitmap, 1234 __u64 bitmap_offset, __u64 bitmap_len) 1235 { 1236 __u64 sector = offset >> SECTOR_SHIFT; 1237 int i; 1238 1239 if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT) 1240 panic("Operation too long"); 1241 1242 if (req_op(req->req) == REQ_OP_READ) { 1243 for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) { 1244 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1245 ubd_set_bit(i, (unsigned char *) 1246 &segment->sector_mask); 1247 } 1248 } else { 1249 cowify_bitmap(offset, segment->length, &segment->sector_mask, 1250 &segment->cow_offset, bitmap, bitmap_offset, 1251 segment->bitmap_words, bitmap_len); 1252 } 1253 } 1254 1255 static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req, 1256 struct request *req) 1257 { 1258 struct bio_vec bvec; 1259 struct req_iterator iter; 1260 int i = 0; 1261 unsigned long byte_offset = io_req->offset; 1262 int op = req_op(req); 1263 1264 if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) { 1265 io_req->io_desc[0].buffer = NULL; 1266 io_req->io_desc[0].length = blk_rq_bytes(req); 1267 } else { 1268 rq_for_each_segment(bvec, req, iter) { 1269 BUG_ON(i >= io_req->desc_cnt); 1270 1271 io_req->io_desc[i].buffer = bvec_virt(&bvec); 1272 io_req->io_desc[i].length = bvec.bv_len; 1273 i++; 1274 } 1275 } 1276 1277 if (dev->cow.file) { 1278 for (i = 0; i < io_req->desc_cnt; i++) { 1279 cowify_req(io_req, &io_req->io_desc[i], byte_offset, 1280 dev->cow.bitmap, dev->cow.bitmap_offset, 1281 dev->cow.bitmap_len); 1282 byte_offset += io_req->io_desc[i].length; 1283 } 1284 1285 } 1286 } 1287 1288 static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req, 1289 int desc_cnt) 1290 { 1291 struct io_thread_req *io_req; 1292 int i; 1293 1294 io_req = kmalloc(sizeof(*io_req) + 1295 (desc_cnt * sizeof(struct io_desc)), 1296 GFP_ATOMIC); 1297 if (!io_req) 1298 return NULL; 1299 1300 io_req->req = req; 1301 if (dev->cow.file) 1302 io_req->fds[0] = dev->cow.fd; 1303 else 1304 io_req->fds[0] = dev->fd; 1305 io_req->error = 0; 1306 io_req->sectorsize = SECTOR_SIZE; 1307 io_req->fds[1] = dev->fd; 1308 io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT; 1309 io_req->offsets[0] = 0; 1310 io_req->offsets[1] = dev->cow.data_offset; 1311 1312 for (i = 0 ; i < desc_cnt; i++) { 1313 io_req->io_desc[i].sector_mask = 0; 1314 io_req->io_desc[i].cow_offset = -1; 1315 } 1316 1317 return io_req; 1318 } 1319 1320 static int ubd_submit_request(struct ubd *dev, struct request *req) 1321 { 1322 int segs = 0; 1323 struct io_thread_req *io_req; 1324 int ret; 1325 int op = req_op(req); 1326 1327 if (op == REQ_OP_FLUSH) 1328 segs = 0; 1329 else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) 1330 segs = 1; 1331 else 1332 segs = blk_rq_nr_phys_segments(req); 1333 1334 io_req = ubd_alloc_req(dev, req, segs); 1335 if (!io_req) 1336 return -ENOMEM; 1337 1338 io_req->desc_cnt = segs; 1339 if (segs) 1340 ubd_map_req(dev, io_req, req); 1341 1342 ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); 1343 if (ret != sizeof(io_req)) { 1344 if (ret != -EAGAIN) 1345 pr_err("write to io thread failed: %d\n", -ret); 1346 kfree(io_req); 1347 } 1348 return ret; 1349 } 1350 1351 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 1352 const struct blk_mq_queue_data *bd) 1353 { 1354 struct ubd *ubd_dev = hctx->queue->queuedata; 1355 struct request *req = bd->rq; 1356 int ret = 0, res = BLK_STS_OK; 1357 1358 blk_mq_start_request(req); 1359 1360 spin_lock_irq(&ubd_dev->lock); 1361 1362 switch (req_op(req)) { 1363 case REQ_OP_FLUSH: 1364 case REQ_OP_READ: 1365 case REQ_OP_WRITE: 1366 case REQ_OP_DISCARD: 1367 case REQ_OP_WRITE_ZEROES: 1368 ret = ubd_submit_request(ubd_dev, req); 1369 break; 1370 default: 1371 WARN_ON_ONCE(1); 1372 res = BLK_STS_NOTSUPP; 1373 } 1374 1375 spin_unlock_irq(&ubd_dev->lock); 1376 1377 if (ret < 0) { 1378 if (ret == -ENOMEM) 1379 res = BLK_STS_RESOURCE; 1380 else 1381 res = BLK_STS_DEV_RESOURCE; 1382 } 1383 1384 return res; 1385 } 1386 1387 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) 1388 { 1389 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1390 1391 geo->heads = 128; 1392 geo->sectors = 32; 1393 geo->cylinders = ubd_dev->size / (128 * 32 * 512); 1394 return 0; 1395 } 1396 1397 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 1398 unsigned int cmd, unsigned long arg) 1399 { 1400 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1401 u16 ubd_id[ATA_ID_WORDS]; 1402 1403 switch (cmd) { 1404 struct cdrom_volctrl volume; 1405 case HDIO_GET_IDENTITY: 1406 memset(&ubd_id, 0, ATA_ID_WORDS * 2); 1407 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); 1408 ubd_id[ATA_ID_HEADS] = 128; 1409 ubd_id[ATA_ID_SECTORS] = 32; 1410 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1411 sizeof(ubd_id))) 1412 return -EFAULT; 1413 return 0; 1414 1415 case CDROMVOLREAD: 1416 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1417 return -EFAULT; 1418 volume.channel0 = 255; 1419 volume.channel1 = 255; 1420 volume.channel2 = 255; 1421 volume.channel3 = 255; 1422 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1423 return -EFAULT; 1424 return 0; 1425 } 1426 return -EINVAL; 1427 } 1428 1429 static int map_error(int error_code) 1430 { 1431 switch (error_code) { 1432 case 0: 1433 return BLK_STS_OK; 1434 case ENOSYS: 1435 case EOPNOTSUPP: 1436 return BLK_STS_NOTSUPP; 1437 case ENOSPC: 1438 return BLK_STS_NOSPC; 1439 } 1440 return BLK_STS_IOERR; 1441 } 1442 1443 /* 1444 * Everything from here onwards *IS NOT PART OF THE KERNEL* 1445 * 1446 * The following functions are part of UML hypervisor code. 1447 * All functions from here onwards are executed as a helper 1448 * thread and are not allowed to execute any kernel functions. 1449 * 1450 * Any communication must occur strictly via shared memory and IPC. 1451 * 1452 * Do not add printks, locks, kernel memory operations, etc - it 1453 * will result in unpredictable behaviour and/or crashes. 1454 */ 1455 1456 static int update_bitmap(struct io_thread_req *req, struct io_desc *segment) 1457 { 1458 int n; 1459 1460 if (segment->cow_offset == -1) 1461 return map_error(0); 1462 1463 n = os_pwrite_file(req->fds[1], &segment->bitmap_words, 1464 sizeof(segment->bitmap_words), segment->cow_offset); 1465 if (n != sizeof(segment->bitmap_words)) 1466 return map_error(-n); 1467 1468 return map_error(0); 1469 } 1470 1471 static void do_io(struct io_thread_req *req, struct io_desc *desc) 1472 { 1473 char *buf = NULL; 1474 unsigned long len; 1475 int n, nsectors, start, end, bit; 1476 __u64 off; 1477 1478 /* FLUSH is really a special case, we cannot "case" it with others */ 1479 1480 if (req_op(req->req) == REQ_OP_FLUSH) { 1481 /* fds[0] is always either the rw image or our cow file */ 1482 req->error = map_error(-os_sync_file(req->fds[0])); 1483 return; 1484 } 1485 1486 nsectors = desc->length / req->sectorsize; 1487 start = 0; 1488 do { 1489 bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask); 1490 end = start; 1491 while((end < nsectors) && 1492 (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit)) 1493 end++; 1494 1495 off = req->offset + req->offsets[bit] + 1496 start * req->sectorsize; 1497 len = (end - start) * req->sectorsize; 1498 if (desc->buffer != NULL) 1499 buf = &desc->buffer[start * req->sectorsize]; 1500 1501 switch (req_op(req->req)) { 1502 case REQ_OP_READ: 1503 n = 0; 1504 do { 1505 buf = &buf[n]; 1506 len -= n; 1507 n = os_pread_file(req->fds[bit], buf, len, off); 1508 if (n < 0) { 1509 req->error = map_error(-n); 1510 return; 1511 } 1512 } while((n < len) && (n != 0)); 1513 if (n < len) memset(&buf[n], 0, len - n); 1514 break; 1515 case REQ_OP_WRITE: 1516 n = os_pwrite_file(req->fds[bit], buf, len, off); 1517 if(n != len){ 1518 req->error = map_error(-n); 1519 return; 1520 } 1521 break; 1522 case REQ_OP_DISCARD: 1523 case REQ_OP_WRITE_ZEROES: 1524 n = os_falloc_punch(req->fds[bit], off, len); 1525 if (n) { 1526 req->error = map_error(-n); 1527 return; 1528 } 1529 break; 1530 default: 1531 WARN_ON_ONCE(1); 1532 req->error = BLK_STS_NOTSUPP; 1533 return; 1534 } 1535 1536 start = end; 1537 } while(start < nsectors); 1538 1539 req->offset += len; 1540 req->error = update_bitmap(req, desc); 1541 } 1542 1543 /* Changed in start_io_thread, which is serialized by being called only 1544 * from ubd_init, which is an initcall. 1545 */ 1546 int kernel_fd = -1; 1547 1548 /* Only changed by the io thread. XXX: currently unused. */ 1549 static int io_count = 0; 1550 1551 int io_thread(void *arg) 1552 { 1553 int n, count, written, res; 1554 1555 os_fix_helper_signals(); 1556 1557 while(1){ 1558 n = bulk_req_safe_read( 1559 kernel_fd, 1560 io_req_buffer, 1561 &io_remainder, 1562 &io_remainder_size, 1563 UBD_REQ_BUFFER_SIZE 1564 ); 1565 if (n <= 0) { 1566 if (n == -EAGAIN) 1567 ubd_read_poll(-1); 1568 1569 continue; 1570 } 1571 1572 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 1573 struct io_thread_req *req = (*io_req_buffer)[count]; 1574 int i; 1575 1576 io_count++; 1577 for (i = 0; !req->error && i < req->desc_cnt; i++) 1578 do_io(req, &(req->io_desc[i])); 1579 1580 } 1581 1582 written = 0; 1583 1584 do { 1585 res = os_write_file(kernel_fd, 1586 ((char *) io_req_buffer) + written, 1587 n - written); 1588 if (res >= 0) { 1589 written += res; 1590 } 1591 if (written < n) { 1592 ubd_write_poll(-1); 1593 } 1594 } while (written < n); 1595 } 1596 1597 return 0; 1598 } 1599