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 int fake_major = UBD_MAJOR; 129 static struct gendisk *ubd_gendisk[MAX_DEV]; 130 static struct gendisk *fake_gendisk[MAX_DEV]; 131 132 #ifdef CONFIG_BLK_DEV_UBD_SYNC 133 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 134 .cl = 1 }) 135 #else 136 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 137 .cl = 1 }) 138 #endif 139 static struct openflags global_openflags = OPEN_FLAGS; 140 141 struct cow { 142 /* backing file name */ 143 char *file; 144 /* backing file fd */ 145 int fd; 146 unsigned long *bitmap; 147 unsigned long bitmap_len; 148 int bitmap_offset; 149 int data_offset; 150 }; 151 152 #define MAX_SG 64 153 154 struct ubd { 155 /* name (and fd, below) of the file opened for writing, either the 156 * backing or the cow file. */ 157 char *file; 158 int count; 159 int fd; 160 __u64 size; 161 struct openflags boot_openflags; 162 struct openflags openflags; 163 unsigned shared:1; 164 unsigned no_cow:1; 165 unsigned no_trim:1; 166 struct cow cow; 167 struct platform_device pdev; 168 struct request_queue *queue; 169 struct blk_mq_tag_set tag_set; 170 spinlock_t lock; 171 }; 172 173 #define DEFAULT_COW { \ 174 .file = NULL, \ 175 .fd = -1, \ 176 .bitmap = NULL, \ 177 .bitmap_offset = 0, \ 178 .data_offset = 0, \ 179 } 180 181 #define DEFAULT_UBD { \ 182 .file = 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 /* Only changed by fake_ide_setup which is a setup */ 199 static int fake_ide = 0; 200 static struct proc_dir_entry *proc_ide_root = NULL; 201 static struct proc_dir_entry *proc_ide = NULL; 202 203 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 204 const struct blk_mq_queue_data *bd); 205 206 static void make_proc_ide(void) 207 { 208 proc_ide_root = proc_mkdir("ide", NULL); 209 proc_ide = proc_mkdir("ide0", proc_ide_root); 210 } 211 212 static int fake_ide_media_proc_show(struct seq_file *m, void *v) 213 { 214 seq_puts(m, "disk\n"); 215 return 0; 216 } 217 218 static void make_ide_entries(const char *dev_name) 219 { 220 struct proc_dir_entry *dir, *ent; 221 char name[64]; 222 223 if(proc_ide_root == NULL) make_proc_ide(); 224 225 dir = proc_mkdir(dev_name, proc_ide); 226 if(!dir) return; 227 228 ent = proc_create_single("media", S_IRUGO, dir, 229 fake_ide_media_proc_show); 230 if(!ent) return; 231 snprintf(name, sizeof(name), "ide0/%s", dev_name); 232 proc_symlink(dev_name, proc_ide_root, name); 233 } 234 235 static int fake_ide_setup(char *str) 236 { 237 fake_ide = 1; 238 return 1; 239 } 240 241 __setup("fake_ide", fake_ide_setup); 242 243 __uml_help(fake_ide_setup, 244 "fake_ide\n" 245 " Create ide0 entries that map onto ubd devices.\n\n" 246 ); 247 248 static int parse_unit(char **ptr) 249 { 250 char *str = *ptr, *end; 251 int n = -1; 252 253 if(isdigit(*str)) { 254 n = simple_strtoul(str, &end, 0); 255 if(end == str) 256 return -1; 257 *ptr = end; 258 } 259 else if (('a' <= *str) && (*str <= 'z')) { 260 n = *str - 'a'; 261 str++; 262 *ptr = str; 263 } 264 return n; 265 } 266 267 /* If *index_out == -1 at exit, the passed option was a general one; 268 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it 269 * should not be freed on exit. 270 */ 271 static int ubd_setup_common(char *str, int *index_out, char **error_out) 272 { 273 struct ubd *ubd_dev; 274 struct openflags flags = global_openflags; 275 char *backing_file; 276 int n, err = 0, i; 277 278 if(index_out) *index_out = -1; 279 n = *str; 280 if(n == '='){ 281 char *end; 282 int major; 283 284 str++; 285 if(!strcmp(str, "sync")){ 286 global_openflags = of_sync(global_openflags); 287 return err; 288 } 289 290 err = -EINVAL; 291 major = simple_strtoul(str, &end, 0); 292 if((*end != '\0') || (end == str)){ 293 *error_out = "Didn't parse major number"; 294 return err; 295 } 296 297 mutex_lock(&ubd_lock); 298 if (fake_major != UBD_MAJOR) { 299 *error_out = "Can't assign a fake major twice"; 300 goto out1; 301 } 302 303 fake_major = major; 304 305 printk(KERN_INFO "Setting extra ubd major number to %d\n", 306 major); 307 err = 0; 308 out1: 309 mutex_unlock(&ubd_lock); 310 return err; 311 } 312 313 n = parse_unit(&str); 314 if(n < 0){ 315 *error_out = "Couldn't parse device number"; 316 return -EINVAL; 317 } 318 if(n >= MAX_DEV){ 319 *error_out = "Device number out of range"; 320 return 1; 321 } 322 323 err = -EBUSY; 324 mutex_lock(&ubd_lock); 325 326 ubd_dev = &ubd_devs[n]; 327 if(ubd_dev->file != NULL){ 328 *error_out = "Device is already configured"; 329 goto out; 330 } 331 332 if (index_out) 333 *index_out = n; 334 335 err = -EINVAL; 336 for (i = 0; i < sizeof("rscdt="); i++) { 337 switch (*str) { 338 case 'r': 339 flags.w = 0; 340 break; 341 case 's': 342 flags.s = 1; 343 break; 344 case 'd': 345 ubd_dev->no_cow = 1; 346 break; 347 case 'c': 348 ubd_dev->shared = 1; 349 break; 350 case 't': 351 ubd_dev->no_trim = 1; 352 break; 353 case '=': 354 str++; 355 goto break_loop; 356 default: 357 *error_out = "Expected '=' or flag letter " 358 "(r, s, c, t or d)"; 359 goto out; 360 } 361 str++; 362 } 363 364 if (*str == '=') 365 *error_out = "Too many flags specified"; 366 else 367 *error_out = "Missing '='"; 368 goto out; 369 370 break_loop: 371 backing_file = strchr(str, ','); 372 373 if (backing_file == NULL) 374 backing_file = strchr(str, ':'); 375 376 if(backing_file != NULL){ 377 if(ubd_dev->no_cow){ 378 *error_out = "Can't specify both 'd' and a cow file"; 379 goto out; 380 } 381 else { 382 *backing_file = '\0'; 383 backing_file++; 384 } 385 } 386 err = 0; 387 ubd_dev->file = str; 388 ubd_dev->cow.file = backing_file; 389 ubd_dev->boot_openflags = flags; 390 out: 391 mutex_unlock(&ubd_lock); 392 return err; 393 } 394 395 static int ubd_setup(char *str) 396 { 397 char *error; 398 int err; 399 400 err = ubd_setup_common(str, NULL, &error); 401 if(err) 402 printk(KERN_ERR "Failed to initialize device with \"%s\" : " 403 "%s\n", str, error); 404 return 1; 405 } 406 407 __setup("ubd", ubd_setup); 408 __uml_help(ubd_setup, 409 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" 410 " This is used to associate a device with a file in the underlying\n" 411 " filesystem. When specifying two filenames, the first one is the\n" 412 " COW name and the second is the backing file name. As separator you can\n" 413 " use either a ':' or a ',': the first one allows writing things like;\n" 414 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 415 " while with a ',' the shell would not expand the 2nd '~'.\n" 416 " When using only one filename, UML will detect whether to treat it like\n" 417 " a COW file or a backing file. To override this detection, add the 'd'\n" 418 " flag:\n" 419 " ubd0d=BackingFile\n" 420 " Usually, there is a filesystem in the file, but \n" 421 " that's not required. Swap devices containing swap files can be\n" 422 " specified like this. Also, a file which doesn't contain a\n" 423 " filesystem can have its contents read in the virtual \n" 424 " machine by running 'dd' on the device. <n> must be in the range\n" 425 " 0 to 7. Appending an 'r' to the number will cause that device\n" 426 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 427 " an 's' will cause data to be written to disk on the host immediately.\n" 428 " 'c' will cause the device to be treated as being shared between multiple\n" 429 " UMLs and file locking will be turned off - this is appropriate for a\n" 430 " cluster filesystem and inappropriate at almost all other times.\n\n" 431 " 't' will disable trim/discard support on the device (enabled by default).\n\n" 432 ); 433 434 static int udb_setup(char *str) 435 { 436 printk("udb%s specified on command line is almost certainly a ubd -> " 437 "udb TYPO\n", str); 438 return 1; 439 } 440 441 __setup("udb", udb_setup); 442 __uml_help(udb_setup, 443 "udb\n" 444 " This option is here solely to catch ubd -> udb typos, which can be\n" 445 " to impossible to catch visually unless you specifically look for\n" 446 " them. The only result of any option starting with 'udb' is an error\n" 447 " in the boot output.\n\n" 448 ); 449 450 /* Only changed by ubd_init, which is an initcall. */ 451 static int thread_fd = -1; 452 453 /* Function to read several request pointers at a time 454 * handling fractional reads if (and as) needed 455 */ 456 457 static int bulk_req_safe_read( 458 int fd, 459 struct io_thread_req * (*request_buffer)[], 460 struct io_thread_req **remainder, 461 int *remainder_size, 462 int max_recs 463 ) 464 { 465 int n = 0; 466 int res = 0; 467 468 if (*remainder_size > 0) { 469 memmove( 470 (char *) request_buffer, 471 (char *) remainder, *remainder_size 472 ); 473 n = *remainder_size; 474 } 475 476 res = os_read_file( 477 fd, 478 ((char *) request_buffer) + *remainder_size, 479 sizeof(struct io_thread_req *)*max_recs 480 - *remainder_size 481 ); 482 if (res > 0) { 483 n += res; 484 if ((n % sizeof(struct io_thread_req *)) > 0) { 485 /* 486 * Read somehow returned not a multiple of dword 487 * theoretically possible, but never observed in the 488 * wild, so read routine must be able to handle it 489 */ 490 *remainder_size = n % sizeof(struct io_thread_req *); 491 WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); 492 memmove( 493 remainder, 494 ((char *) request_buffer) + 495 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), 496 *remainder_size 497 ); 498 n = n - *remainder_size; 499 } 500 } else { 501 n = res; 502 } 503 return n; 504 } 505 506 /* Called without dev->lock held, and only in interrupt context. */ 507 static void ubd_handler(void) 508 { 509 int n; 510 int count; 511 512 while(1){ 513 n = bulk_req_safe_read( 514 thread_fd, 515 irq_req_buffer, 516 &irq_remainder, 517 &irq_remainder_size, 518 UBD_REQ_BUFFER_SIZE 519 ); 520 if (n < 0) { 521 if(n == -EAGAIN) 522 break; 523 printk(KERN_ERR "spurious interrupt in ubd_handler, " 524 "err = %d\n", -n); 525 return; 526 } 527 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 528 struct io_thread_req *io_req = (*irq_req_buffer)[count]; 529 530 if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) { 531 blk_queue_max_discard_sectors(io_req->req->q, 0); 532 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0); 533 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q); 534 } 535 blk_mq_end_request(io_req->req, io_req->error); 536 kfree(io_req); 537 } 538 } 539 } 540 541 static irqreturn_t ubd_intr(int irq, void *dev) 542 { 543 ubd_handler(); 544 return IRQ_HANDLED; 545 } 546 547 /* Only changed by ubd_init, which is an initcall. */ 548 static int io_pid = -1; 549 550 static void kill_io_thread(void) 551 { 552 if(io_pid != -1) 553 os_kill_process(io_pid, 1); 554 } 555 556 __uml_exitcall(kill_io_thread); 557 558 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) 559 { 560 char *file; 561 int fd; 562 int err; 563 564 __u32 version; 565 __u32 align; 566 char *backing_file; 567 time64_t mtime; 568 unsigned long long size; 569 int sector_size; 570 int bitmap_offset; 571 572 if (ubd_dev->file && ubd_dev->cow.file) { 573 file = ubd_dev->cow.file; 574 575 goto out; 576 } 577 578 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); 579 if (fd < 0) 580 return fd; 581 582 err = read_cow_header(file_reader, &fd, &version, &backing_file, \ 583 &mtime, &size, §or_size, &align, &bitmap_offset); 584 os_close_file(fd); 585 586 if(err == -EINVAL) 587 file = ubd_dev->file; 588 else 589 file = backing_file; 590 591 out: 592 return os_file_size(file, size_out); 593 } 594 595 static int read_cow_bitmap(int fd, void *buf, int offset, int len) 596 { 597 int err; 598 599 err = os_pread_file(fd, buf, len, offset); 600 if (err < 0) 601 return err; 602 603 return 0; 604 } 605 606 static int backing_file_mismatch(char *file, __u64 size, time64_t mtime) 607 { 608 time64_t modtime; 609 unsigned long long actual; 610 int err; 611 612 err = os_file_modtime(file, &modtime); 613 if (err < 0) { 614 printk(KERN_ERR "Failed to get modification time of backing " 615 "file \"%s\", err = %d\n", file, -err); 616 return err; 617 } 618 619 err = os_file_size(file, &actual); 620 if (err < 0) { 621 printk(KERN_ERR "Failed to get size of backing file \"%s\", " 622 "err = %d\n", file, -err); 623 return err; 624 } 625 626 if (actual != size) { 627 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 628 * the typecast.*/ 629 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " 630 "vs backing file\n", (unsigned long long) size, actual); 631 return -EINVAL; 632 } 633 if (modtime != mtime) { 634 printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs " 635 "backing file\n", mtime, modtime); 636 return -EINVAL; 637 } 638 return 0; 639 } 640 641 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) 642 { 643 struct uml_stat buf1, buf2; 644 int err; 645 646 if (from_cmdline == NULL) 647 return 0; 648 if (!strcmp(from_cmdline, from_cow)) 649 return 0; 650 651 err = os_stat_file(from_cmdline, &buf1); 652 if (err < 0) { 653 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, 654 -err); 655 return 0; 656 } 657 err = os_stat_file(from_cow, &buf2); 658 if (err < 0) { 659 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow, 660 -err); 661 return 1; 662 } 663 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 664 return 0; 665 666 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, " 667 "\"%s\" specified in COW header of \"%s\"\n", 668 from_cmdline, from_cow, cow); 669 return 1; 670 } 671 672 static int open_ubd_file(char *file, struct openflags *openflags, int shared, 673 char **backing_file_out, int *bitmap_offset_out, 674 unsigned long *bitmap_len_out, int *data_offset_out, 675 int *create_cow_out) 676 { 677 time64_t mtime; 678 unsigned long long size; 679 __u32 version, align; 680 char *backing_file; 681 int fd, err, sectorsize, asked_switch, mode = 0644; 682 683 fd = os_open_file(file, *openflags, mode); 684 if (fd < 0) { 685 if ((fd == -ENOENT) && (create_cow_out != NULL)) 686 *create_cow_out = 1; 687 if (!openflags->w || 688 ((fd != -EROFS) && (fd != -EACCES))) 689 return fd; 690 openflags->w = 0; 691 fd = os_open_file(file, *openflags, mode); 692 if (fd < 0) 693 return fd; 694 } 695 696 if (shared) 697 printk(KERN_INFO "Not locking \"%s\" on the host\n", file); 698 else { 699 err = os_lock_file(fd, openflags->w); 700 if (err < 0) { 701 printk(KERN_ERR "Failed to lock '%s', err = %d\n", 702 file, -err); 703 goto out_close; 704 } 705 } 706 707 /* Successful return case! */ 708 if (backing_file_out == NULL) 709 return fd; 710 711 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 712 &size, §orsize, &align, bitmap_offset_out); 713 if (err && (*backing_file_out != NULL)) { 714 printk(KERN_ERR "Failed to read COW header from COW file " 715 "\"%s\", errno = %d\n", file, -err); 716 goto out_close; 717 } 718 if (err) 719 return fd; 720 721 asked_switch = path_requires_switch(*backing_file_out, backing_file, 722 file); 723 724 /* Allow switching only if no mismatch. */ 725 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, 726 mtime)) { 727 printk(KERN_ERR "Switching backing file to '%s'\n", 728 *backing_file_out); 729 err = write_cow_header(file, fd, *backing_file_out, 730 sectorsize, align, &size); 731 if (err) { 732 printk(KERN_ERR "Switch failed, errno = %d\n", -err); 733 goto out_close; 734 } 735 } else { 736 *backing_file_out = backing_file; 737 err = backing_file_mismatch(*backing_file_out, size, mtime); 738 if (err) 739 goto out_close; 740 } 741 742 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 743 bitmap_len_out, data_offset_out); 744 745 return fd; 746 out_close: 747 os_close_file(fd); 748 return err; 749 } 750 751 static int create_cow_file(char *cow_file, char *backing_file, 752 struct openflags flags, 753 int sectorsize, int alignment, int *bitmap_offset_out, 754 unsigned long *bitmap_len_out, int *data_offset_out) 755 { 756 int err, fd; 757 758 flags.c = 1; 759 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); 760 if (fd < 0) { 761 err = fd; 762 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n", 763 cow_file, -err); 764 goto out; 765 } 766 767 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 768 bitmap_offset_out, bitmap_len_out, 769 data_offset_out); 770 if (!err) 771 return fd; 772 os_close_file(fd); 773 out: 774 return err; 775 } 776 777 static void ubd_close_dev(struct ubd *ubd_dev) 778 { 779 os_close_file(ubd_dev->fd); 780 if(ubd_dev->cow.file == NULL) 781 return; 782 783 os_close_file(ubd_dev->cow.fd); 784 vfree(ubd_dev->cow.bitmap); 785 ubd_dev->cow.bitmap = NULL; 786 } 787 788 static int ubd_open_dev(struct ubd *ubd_dev) 789 { 790 struct openflags flags; 791 char **back_ptr; 792 int err, create_cow, *create_ptr; 793 int fd; 794 795 ubd_dev->openflags = ubd_dev->boot_openflags; 796 create_cow = 0; 797 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; 798 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; 799 800 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, 801 back_ptr, &ubd_dev->cow.bitmap_offset, 802 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, 803 create_ptr); 804 805 if((fd == -ENOENT) && create_cow){ 806 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, 807 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE, 808 &ubd_dev->cow.bitmap_offset, 809 &ubd_dev->cow.bitmap_len, 810 &ubd_dev->cow.data_offset); 811 if(fd >= 0){ 812 printk(KERN_INFO "Creating \"%s\" as COW file for " 813 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); 814 } 815 } 816 817 if(fd < 0){ 818 printk("Failed to open '%s', errno = %d\n", ubd_dev->file, 819 -fd); 820 return fd; 821 } 822 ubd_dev->fd = fd; 823 824 if(ubd_dev->cow.file != NULL){ 825 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long)); 826 827 err = -ENOMEM; 828 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len); 829 if(ubd_dev->cow.bitmap == NULL){ 830 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 831 goto error; 832 } 833 flush_tlb_kernel_vm(); 834 835 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, 836 ubd_dev->cow.bitmap_offset, 837 ubd_dev->cow.bitmap_len); 838 if(err < 0) 839 goto error; 840 841 flags = ubd_dev->openflags; 842 flags.w = 0; 843 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, 844 NULL, NULL, NULL, NULL); 845 if(err < 0) goto error; 846 ubd_dev->cow.fd = err; 847 } 848 if (ubd_dev->no_trim == 0) { 849 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE; 850 ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE; 851 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST); 852 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST); 853 blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue); 854 } 855 blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue); 856 return 0; 857 error: 858 os_close_file(ubd_dev->fd); 859 return err; 860 } 861 862 static void ubd_device_release(struct device *dev) 863 { 864 struct ubd *ubd_dev = dev_get_drvdata(dev); 865 866 blk_cleanup_queue(ubd_dev->queue); 867 blk_mq_free_tag_set(&ubd_dev->tag_set); 868 *ubd_dev = ((struct ubd) DEFAULT_UBD); 869 } 870 871 static int ubd_disk_register(int major, u64 size, int unit, 872 struct gendisk **disk_out) 873 { 874 struct device *parent = NULL; 875 struct gendisk *disk; 876 877 disk = alloc_disk(1 << UBD_SHIFT); 878 if(disk == NULL) 879 return -ENOMEM; 880 881 disk->major = major; 882 disk->first_minor = unit << UBD_SHIFT; 883 disk->fops = &ubd_blops; 884 set_capacity(disk, size / 512); 885 if (major == UBD_MAJOR) 886 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 887 else 888 sprintf(disk->disk_name, "ubd_fake%d", unit); 889 890 /* sysfs register (not for ide fake devices) */ 891 if (major == UBD_MAJOR) { 892 ubd_devs[unit].pdev.id = unit; 893 ubd_devs[unit].pdev.name = DRIVER_NAME; 894 ubd_devs[unit].pdev.dev.release = ubd_device_release; 895 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]); 896 platform_device_register(&ubd_devs[unit].pdev); 897 parent = &ubd_devs[unit].pdev.dev; 898 } 899 900 disk->private_data = &ubd_devs[unit]; 901 disk->queue = ubd_devs[unit].queue; 902 device_add_disk(parent, disk, NULL); 903 904 *disk_out = disk; 905 return 0; 906 } 907 908 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE)) 909 910 static const struct blk_mq_ops ubd_mq_ops = { 911 .queue_rq = ubd_queue_rq, 912 }; 913 914 static int ubd_add(int n, char **error_out) 915 { 916 struct ubd *ubd_dev = &ubd_devs[n]; 917 int err = 0; 918 919 if(ubd_dev->file == NULL) 920 goto out; 921 922 err = ubd_file_size(ubd_dev, &ubd_dev->size); 923 if(err < 0){ 924 *error_out = "Couldn't determine size of device's file"; 925 goto out; 926 } 927 928 ubd_dev->size = ROUND_BLOCK(ubd_dev->size); 929 930 ubd_dev->tag_set.ops = &ubd_mq_ops; 931 ubd_dev->tag_set.queue_depth = 64; 932 ubd_dev->tag_set.numa_node = NUMA_NO_NODE; 933 ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 934 ubd_dev->tag_set.driver_data = ubd_dev; 935 ubd_dev->tag_set.nr_hw_queues = 1; 936 937 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set); 938 if (err) 939 goto out; 940 941 ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set); 942 if (IS_ERR(ubd_dev->queue)) { 943 err = PTR_ERR(ubd_dev->queue); 944 goto out_cleanup_tags; 945 } 946 947 ubd_dev->queue->queuedata = ubd_dev; 948 blk_queue_write_cache(ubd_dev->queue, true, false); 949 950 blk_queue_max_segments(ubd_dev->queue, MAX_SG); 951 blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1); 952 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]); 953 if(err){ 954 *error_out = "Failed to register device"; 955 goto out_cleanup_tags; 956 } 957 958 if (fake_major != UBD_MAJOR) 959 ubd_disk_register(fake_major, ubd_dev->size, n, 960 &fake_gendisk[n]); 961 962 /* 963 * Perhaps this should also be under the "if (fake_major)" above 964 * using the fake_disk->disk_name 965 */ 966 if (fake_ide) 967 make_ide_entries(ubd_gendisk[n]->disk_name); 968 969 err = 0; 970 out: 971 return err; 972 973 out_cleanup_tags: 974 blk_mq_free_tag_set(&ubd_dev->tag_set); 975 if (!(IS_ERR(ubd_dev->queue))) 976 blk_cleanup_queue(ubd_dev->queue); 977 goto out; 978 } 979 980 static int ubd_config(char *str, char **error_out) 981 { 982 int n, ret; 983 984 /* This string is possibly broken up and stored, so it's only 985 * freed if ubd_setup_common fails, or if only general options 986 * were set. 987 */ 988 str = kstrdup(str, GFP_KERNEL); 989 if (str == NULL) { 990 *error_out = "Failed to allocate memory"; 991 return -ENOMEM; 992 } 993 994 ret = ubd_setup_common(str, &n, error_out); 995 if (ret) 996 goto err_free; 997 998 if (n == -1) { 999 ret = 0; 1000 goto err_free; 1001 } 1002 1003 mutex_lock(&ubd_lock); 1004 ret = ubd_add(n, error_out); 1005 if (ret) 1006 ubd_devs[n].file = NULL; 1007 mutex_unlock(&ubd_lock); 1008 1009 out: 1010 return ret; 1011 1012 err_free: 1013 kfree(str); 1014 goto out; 1015 } 1016 1017 static int ubd_get_config(char *name, char *str, int size, char **error_out) 1018 { 1019 struct ubd *ubd_dev; 1020 int n, len = 0; 1021 1022 n = parse_unit(&name); 1023 if((n >= MAX_DEV) || (n < 0)){ 1024 *error_out = "ubd_get_config : device number out of range"; 1025 return -1; 1026 } 1027 1028 ubd_dev = &ubd_devs[n]; 1029 mutex_lock(&ubd_lock); 1030 1031 if(ubd_dev->file == NULL){ 1032 CONFIG_CHUNK(str, size, len, "", 1); 1033 goto out; 1034 } 1035 1036 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); 1037 1038 if(ubd_dev->cow.file != NULL){ 1039 CONFIG_CHUNK(str, size, len, ",", 0); 1040 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); 1041 } 1042 else CONFIG_CHUNK(str, size, len, "", 1); 1043 1044 out: 1045 mutex_unlock(&ubd_lock); 1046 return len; 1047 } 1048 1049 static int ubd_id(char **str, int *start_out, int *end_out) 1050 { 1051 int n; 1052 1053 n = parse_unit(str); 1054 *start_out = 0; 1055 *end_out = MAX_DEV - 1; 1056 return n; 1057 } 1058 1059 static int ubd_remove(int n, char **error_out) 1060 { 1061 struct gendisk *disk = ubd_gendisk[n]; 1062 struct ubd *ubd_dev; 1063 int err = -ENODEV; 1064 1065 mutex_lock(&ubd_lock); 1066 1067 ubd_dev = &ubd_devs[n]; 1068 1069 if(ubd_dev->file == NULL) 1070 goto out; 1071 1072 /* you cannot remove a open disk */ 1073 err = -EBUSY; 1074 if(ubd_dev->count > 0) 1075 goto out; 1076 1077 ubd_gendisk[n] = NULL; 1078 if(disk != NULL){ 1079 del_gendisk(disk); 1080 put_disk(disk); 1081 } 1082 1083 if(fake_gendisk[n] != NULL){ 1084 del_gendisk(fake_gendisk[n]); 1085 put_disk(fake_gendisk[n]); 1086 fake_gendisk[n] = NULL; 1087 } 1088 1089 err = 0; 1090 platform_device_unregister(&ubd_dev->pdev); 1091 out: 1092 mutex_unlock(&ubd_lock); 1093 return err; 1094 } 1095 1096 /* All these are called by mconsole in process context and without 1097 * ubd-specific locks. The structure itself is const except for .list. 1098 */ 1099 static struct mc_device ubd_mc = { 1100 .list = LIST_HEAD_INIT(ubd_mc.list), 1101 .name = "ubd", 1102 .config = ubd_config, 1103 .get_config = ubd_get_config, 1104 .id = ubd_id, 1105 .remove = ubd_remove, 1106 }; 1107 1108 static int __init ubd_mc_init(void) 1109 { 1110 mconsole_register_dev(&ubd_mc); 1111 return 0; 1112 } 1113 1114 __initcall(ubd_mc_init); 1115 1116 static int __init ubd0_init(void) 1117 { 1118 struct ubd *ubd_dev = &ubd_devs[0]; 1119 1120 mutex_lock(&ubd_lock); 1121 if(ubd_dev->file == NULL) 1122 ubd_dev->file = "root_fs"; 1123 mutex_unlock(&ubd_lock); 1124 1125 return 0; 1126 } 1127 1128 __initcall(ubd0_init); 1129 1130 /* Used in ubd_init, which is an initcall */ 1131 static struct platform_driver ubd_driver = { 1132 .driver = { 1133 .name = DRIVER_NAME, 1134 }, 1135 }; 1136 1137 static int __init ubd_init(void) 1138 { 1139 char *error; 1140 int i, err; 1141 1142 if (register_blkdev(UBD_MAJOR, "ubd")) 1143 return -1; 1144 1145 if (fake_major != UBD_MAJOR) { 1146 char name[sizeof("ubd_nnn\0")]; 1147 1148 snprintf(name, sizeof(name), "ubd_%d", fake_major); 1149 if (register_blkdev(fake_major, "ubd")) 1150 return -1; 1151 } 1152 1153 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1154 sizeof(struct io_thread_req *), 1155 GFP_KERNEL 1156 ); 1157 irq_remainder = 0; 1158 1159 if (irq_req_buffer == NULL) { 1160 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1161 return -1; 1162 } 1163 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1164 sizeof(struct io_thread_req *), 1165 GFP_KERNEL 1166 ); 1167 1168 io_remainder = 0; 1169 1170 if (io_req_buffer == NULL) { 1171 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1172 return -1; 1173 } 1174 platform_driver_register(&ubd_driver); 1175 mutex_lock(&ubd_lock); 1176 for (i = 0; i < MAX_DEV; i++){ 1177 err = ubd_add(i, &error); 1178 if(err) 1179 printk(KERN_ERR "Failed to initialize ubd device %d :" 1180 "%s\n", i, error); 1181 } 1182 mutex_unlock(&ubd_lock); 1183 return 0; 1184 } 1185 1186 late_initcall(ubd_init); 1187 1188 static int __init ubd_driver_init(void){ 1189 unsigned long stack; 1190 int err; 1191 1192 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 1193 if(global_openflags.s){ 1194 printk(KERN_INFO "ubd: Synchronous mode\n"); 1195 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 1196 * enough. So use anyway the io thread. */ 1197 } 1198 stack = alloc_stack(0, 0); 1199 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), 1200 &thread_fd); 1201 if(io_pid < 0){ 1202 printk(KERN_ERR 1203 "ubd : Failed to start I/O thread (errno = %d) - " 1204 "falling back to synchronous I/O\n", -io_pid); 1205 io_pid = -1; 1206 return 0; 1207 } 1208 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 1209 0, "ubd", ubd_devs); 1210 if(err != 0) 1211 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 1212 return 0; 1213 } 1214 1215 device_initcall(ubd_driver_init); 1216 1217 static int ubd_open(struct block_device *bdev, fmode_t mode) 1218 { 1219 struct gendisk *disk = bdev->bd_disk; 1220 struct ubd *ubd_dev = disk->private_data; 1221 int err = 0; 1222 1223 mutex_lock(&ubd_mutex); 1224 if(ubd_dev->count == 0){ 1225 err = ubd_open_dev(ubd_dev); 1226 if(err){ 1227 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 1228 disk->disk_name, ubd_dev->file, -err); 1229 goto out; 1230 } 1231 } 1232 ubd_dev->count++; 1233 set_disk_ro(disk, !ubd_dev->openflags.w); 1234 1235 /* This should no more be needed. And it didn't work anyway to exclude 1236 * read-write remounting of filesystems.*/ 1237 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){ 1238 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); 1239 err = -EROFS; 1240 }*/ 1241 out: 1242 mutex_unlock(&ubd_mutex); 1243 return err; 1244 } 1245 1246 static void ubd_release(struct gendisk *disk, fmode_t mode) 1247 { 1248 struct ubd *ubd_dev = disk->private_data; 1249 1250 mutex_lock(&ubd_mutex); 1251 if(--ubd_dev->count == 0) 1252 ubd_close_dev(ubd_dev); 1253 mutex_unlock(&ubd_mutex); 1254 } 1255 1256 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 1257 __u64 *cow_offset, unsigned long *bitmap, 1258 __u64 bitmap_offset, unsigned long *bitmap_words, 1259 __u64 bitmap_len) 1260 { 1261 __u64 sector = io_offset >> SECTOR_SHIFT; 1262 int i, update_bitmap = 0; 1263 1264 for (i = 0; i < length >> SECTOR_SHIFT; i++) { 1265 if(cow_mask != NULL) 1266 ubd_set_bit(i, (unsigned char *) cow_mask); 1267 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1268 continue; 1269 1270 update_bitmap = 1; 1271 ubd_set_bit(sector + i, (unsigned char *) bitmap); 1272 } 1273 1274 if(!update_bitmap) 1275 return; 1276 1277 *cow_offset = sector / (sizeof(unsigned long) * 8); 1278 1279 /* This takes care of the case where we're exactly at the end of the 1280 * device, and *cow_offset + 1 is off the end. So, just back it up 1281 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 1282 * for the original diagnosis. 1283 */ 1284 if (*cow_offset == (DIV_ROUND_UP(bitmap_len, 1285 sizeof(unsigned long)) - 1)) 1286 (*cow_offset)--; 1287 1288 bitmap_words[0] = bitmap[*cow_offset]; 1289 bitmap_words[1] = bitmap[*cow_offset + 1]; 1290 1291 *cow_offset *= sizeof(unsigned long); 1292 *cow_offset += bitmap_offset; 1293 } 1294 1295 static void cowify_req(struct io_thread_req *req, struct io_desc *segment, 1296 unsigned long offset, unsigned long *bitmap, 1297 __u64 bitmap_offset, __u64 bitmap_len) 1298 { 1299 __u64 sector = offset >> SECTOR_SHIFT; 1300 int i; 1301 1302 if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT) 1303 panic("Operation too long"); 1304 1305 if (req_op(req->req) == REQ_OP_READ) { 1306 for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) { 1307 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1308 ubd_set_bit(i, (unsigned char *) 1309 &segment->sector_mask); 1310 } 1311 } else { 1312 cowify_bitmap(offset, segment->length, &segment->sector_mask, 1313 &segment->cow_offset, bitmap, bitmap_offset, 1314 segment->bitmap_words, bitmap_len); 1315 } 1316 } 1317 1318 static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req, 1319 struct request *req) 1320 { 1321 struct bio_vec bvec; 1322 struct req_iterator iter; 1323 int i = 0; 1324 unsigned long byte_offset = io_req->offset; 1325 int op = req_op(req); 1326 1327 if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) { 1328 io_req->io_desc[0].buffer = NULL; 1329 io_req->io_desc[0].length = blk_rq_bytes(req); 1330 } else { 1331 rq_for_each_segment(bvec, req, iter) { 1332 BUG_ON(i >= io_req->desc_cnt); 1333 1334 io_req->io_desc[i].buffer = 1335 page_address(bvec.bv_page) + bvec.bv_offset; 1336 io_req->io_desc[i].length = bvec.bv_len; 1337 i++; 1338 } 1339 } 1340 1341 if (dev->cow.file) { 1342 for (i = 0; i < io_req->desc_cnt; i++) { 1343 cowify_req(io_req, &io_req->io_desc[i], byte_offset, 1344 dev->cow.bitmap, dev->cow.bitmap_offset, 1345 dev->cow.bitmap_len); 1346 byte_offset += io_req->io_desc[i].length; 1347 } 1348 1349 } 1350 } 1351 1352 static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req, 1353 int desc_cnt) 1354 { 1355 struct io_thread_req *io_req; 1356 int i; 1357 1358 io_req = kmalloc(sizeof(*io_req) + 1359 (desc_cnt * sizeof(struct io_desc)), 1360 GFP_ATOMIC); 1361 if (!io_req) 1362 return NULL; 1363 1364 io_req->req = req; 1365 if (dev->cow.file) 1366 io_req->fds[0] = dev->cow.fd; 1367 else 1368 io_req->fds[0] = dev->fd; 1369 io_req->error = 0; 1370 io_req->sectorsize = SECTOR_SIZE; 1371 io_req->fds[1] = dev->fd; 1372 io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT; 1373 io_req->offsets[0] = 0; 1374 io_req->offsets[1] = dev->cow.data_offset; 1375 1376 for (i = 0 ; i < desc_cnt; i++) { 1377 io_req->io_desc[i].sector_mask = 0; 1378 io_req->io_desc[i].cow_offset = -1; 1379 } 1380 1381 return io_req; 1382 } 1383 1384 static int ubd_submit_request(struct ubd *dev, struct request *req) 1385 { 1386 int segs = 0; 1387 struct io_thread_req *io_req; 1388 int ret; 1389 int op = req_op(req); 1390 1391 if (op == REQ_OP_FLUSH) 1392 segs = 0; 1393 else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) 1394 segs = 1; 1395 else 1396 segs = blk_rq_nr_phys_segments(req); 1397 1398 io_req = ubd_alloc_req(dev, req, segs); 1399 if (!io_req) 1400 return -ENOMEM; 1401 1402 io_req->desc_cnt = segs; 1403 if (segs) 1404 ubd_map_req(dev, io_req, req); 1405 1406 ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); 1407 if (ret != sizeof(io_req)) { 1408 if (ret != -EAGAIN) 1409 pr_err("write to io thread failed: %d\n", -ret); 1410 kfree(io_req); 1411 } 1412 return ret; 1413 } 1414 1415 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 1416 const struct blk_mq_queue_data *bd) 1417 { 1418 struct ubd *ubd_dev = hctx->queue->queuedata; 1419 struct request *req = bd->rq; 1420 int ret = 0, res = BLK_STS_OK; 1421 1422 blk_mq_start_request(req); 1423 1424 spin_lock_irq(&ubd_dev->lock); 1425 1426 switch (req_op(req)) { 1427 case REQ_OP_FLUSH: 1428 case REQ_OP_READ: 1429 case REQ_OP_WRITE: 1430 case REQ_OP_DISCARD: 1431 case REQ_OP_WRITE_ZEROES: 1432 ret = ubd_submit_request(ubd_dev, req); 1433 break; 1434 default: 1435 WARN_ON_ONCE(1); 1436 res = BLK_STS_NOTSUPP; 1437 } 1438 1439 spin_unlock_irq(&ubd_dev->lock); 1440 1441 if (ret < 0) { 1442 if (ret == -ENOMEM) 1443 res = BLK_STS_RESOURCE; 1444 else 1445 res = BLK_STS_DEV_RESOURCE; 1446 } 1447 1448 return res; 1449 } 1450 1451 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) 1452 { 1453 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1454 1455 geo->heads = 128; 1456 geo->sectors = 32; 1457 geo->cylinders = ubd_dev->size / (128 * 32 * 512); 1458 return 0; 1459 } 1460 1461 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 1462 unsigned int cmd, unsigned long arg) 1463 { 1464 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1465 u16 ubd_id[ATA_ID_WORDS]; 1466 1467 switch (cmd) { 1468 struct cdrom_volctrl volume; 1469 case HDIO_GET_IDENTITY: 1470 memset(&ubd_id, 0, ATA_ID_WORDS * 2); 1471 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); 1472 ubd_id[ATA_ID_HEADS] = 128; 1473 ubd_id[ATA_ID_SECTORS] = 32; 1474 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1475 sizeof(ubd_id))) 1476 return -EFAULT; 1477 return 0; 1478 1479 case CDROMVOLREAD: 1480 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1481 return -EFAULT; 1482 volume.channel0 = 255; 1483 volume.channel1 = 255; 1484 volume.channel2 = 255; 1485 volume.channel3 = 255; 1486 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1487 return -EFAULT; 1488 return 0; 1489 } 1490 return -EINVAL; 1491 } 1492 1493 static int map_error(int error_code) 1494 { 1495 switch (error_code) { 1496 case 0: 1497 return BLK_STS_OK; 1498 case ENOSYS: 1499 case EOPNOTSUPP: 1500 return BLK_STS_NOTSUPP; 1501 case ENOSPC: 1502 return BLK_STS_NOSPC; 1503 } 1504 return BLK_STS_IOERR; 1505 } 1506 1507 /* 1508 * Everything from here onwards *IS NOT PART OF THE KERNEL* 1509 * 1510 * The following functions are part of UML hypervisor code. 1511 * All functions from here onwards are executed as a helper 1512 * thread and are not allowed to execute any kernel functions. 1513 * 1514 * Any communication must occur strictly via shared memory and IPC. 1515 * 1516 * Do not add printks, locks, kernel memory operations, etc - it 1517 * will result in unpredictable behaviour and/or crashes. 1518 */ 1519 1520 static int update_bitmap(struct io_thread_req *req, struct io_desc *segment) 1521 { 1522 int n; 1523 1524 if (segment->cow_offset == -1) 1525 return map_error(0); 1526 1527 n = os_pwrite_file(req->fds[1], &segment->bitmap_words, 1528 sizeof(segment->bitmap_words), segment->cow_offset); 1529 if (n != sizeof(segment->bitmap_words)) 1530 return map_error(-n); 1531 1532 return map_error(0); 1533 } 1534 1535 static void do_io(struct io_thread_req *req, struct io_desc *desc) 1536 { 1537 char *buf = NULL; 1538 unsigned long len; 1539 int n, nsectors, start, end, bit; 1540 __u64 off; 1541 1542 /* FLUSH is really a special case, we cannot "case" it with others */ 1543 1544 if (req_op(req->req) == REQ_OP_FLUSH) { 1545 /* fds[0] is always either the rw image or our cow file */ 1546 req->error = map_error(-os_sync_file(req->fds[0])); 1547 return; 1548 } 1549 1550 nsectors = desc->length / req->sectorsize; 1551 start = 0; 1552 do { 1553 bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask); 1554 end = start; 1555 while((end < nsectors) && 1556 (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit)) 1557 end++; 1558 1559 off = req->offset + req->offsets[bit] + 1560 start * req->sectorsize; 1561 len = (end - start) * req->sectorsize; 1562 if (desc->buffer != NULL) 1563 buf = &desc->buffer[start * req->sectorsize]; 1564 1565 switch (req_op(req->req)) { 1566 case REQ_OP_READ: 1567 n = 0; 1568 do { 1569 buf = &buf[n]; 1570 len -= n; 1571 n = os_pread_file(req->fds[bit], buf, len, off); 1572 if (n < 0) { 1573 req->error = map_error(-n); 1574 return; 1575 } 1576 } while((n < len) && (n != 0)); 1577 if (n < len) memset(&buf[n], 0, len - n); 1578 break; 1579 case REQ_OP_WRITE: 1580 n = os_pwrite_file(req->fds[bit], buf, len, off); 1581 if(n != len){ 1582 req->error = map_error(-n); 1583 return; 1584 } 1585 break; 1586 case REQ_OP_DISCARD: 1587 case REQ_OP_WRITE_ZEROES: 1588 n = os_falloc_punch(req->fds[bit], off, len); 1589 if (n) { 1590 req->error = map_error(-n); 1591 return; 1592 } 1593 break; 1594 default: 1595 WARN_ON_ONCE(1); 1596 req->error = BLK_STS_NOTSUPP; 1597 return; 1598 } 1599 1600 start = end; 1601 } while(start < nsectors); 1602 1603 req->offset += len; 1604 req->error = update_bitmap(req, desc); 1605 } 1606 1607 /* Changed in start_io_thread, which is serialized by being called only 1608 * from ubd_init, which is an initcall. 1609 */ 1610 int kernel_fd = -1; 1611 1612 /* Only changed by the io thread. XXX: currently unused. */ 1613 static int io_count = 0; 1614 1615 int io_thread(void *arg) 1616 { 1617 int n, count, written, res; 1618 1619 os_fix_helper_signals(); 1620 1621 while(1){ 1622 n = bulk_req_safe_read( 1623 kernel_fd, 1624 io_req_buffer, 1625 &io_remainder, 1626 &io_remainder_size, 1627 UBD_REQ_BUFFER_SIZE 1628 ); 1629 if (n <= 0) { 1630 if (n == -EAGAIN) 1631 ubd_read_poll(-1); 1632 1633 continue; 1634 } 1635 1636 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 1637 struct io_thread_req *req = (*io_req_buffer)[count]; 1638 int i; 1639 1640 io_count++; 1641 for (i = 0; !req->error && i < req->desc_cnt; i++) 1642 do_io(req, &(req->io_desc[i])); 1643 1644 } 1645 1646 written = 0; 1647 1648 do { 1649 res = os_write_file(kernel_fd, 1650 ((char *) io_req_buffer) + written, 1651 n - written); 1652 if (res >= 0) { 1653 written += res; 1654 } 1655 if (written < n) { 1656 ubd_write_poll(-1); 1657 } 1658 } while (written < n); 1659 } 1660 1661 return 0; 1662 } 1663