1 /* 2 * Copyright (C) 2018 Cambridge Greys Ltd 3 * Copyright (C) 2015-2016 Anton Ivanov (aivanov@brocade.com) 4 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) 5 * Licensed under the GPL 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_thread_req { 51 struct request *req; 52 int fds[2]; 53 unsigned long offsets[2]; 54 unsigned long long offset; 55 unsigned long length; 56 char *buffer; 57 int sectorsize; 58 unsigned long sector_mask; 59 unsigned long long cow_offset; 60 unsigned long bitmap_words[2]; 61 int error; 62 }; 63 64 65 static struct io_thread_req * (*irq_req_buffer)[]; 66 static struct io_thread_req *irq_remainder; 67 static int irq_remainder_size; 68 69 static struct io_thread_req * (*io_req_buffer)[]; 70 static struct io_thread_req *io_remainder; 71 static int io_remainder_size; 72 73 74 75 static inline int ubd_test_bit(__u64 bit, unsigned char *data) 76 { 77 __u64 n; 78 int bits, off; 79 80 bits = sizeof(data[0]) * 8; 81 n = bit / bits; 82 off = bit % bits; 83 return (data[n] & (1 << off)) != 0; 84 } 85 86 static inline void ubd_set_bit(__u64 bit, unsigned char *data) 87 { 88 __u64 n; 89 int bits, off; 90 91 bits = sizeof(data[0]) * 8; 92 n = bit / bits; 93 off = bit % bits; 94 data[n] |= (1 << off); 95 } 96 /*End stuff from ubd_user.h*/ 97 98 #define DRIVER_NAME "uml-blkdev" 99 100 static DEFINE_MUTEX(ubd_lock); 101 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */ 102 103 static int ubd_open(struct block_device *bdev, fmode_t mode); 104 static void ubd_release(struct gendisk *disk, fmode_t mode); 105 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 106 unsigned int cmd, unsigned long arg); 107 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); 108 109 #define MAX_DEV (16) 110 111 static const struct block_device_operations ubd_blops = { 112 .owner = THIS_MODULE, 113 .open = ubd_open, 114 .release = ubd_release, 115 .ioctl = ubd_ioctl, 116 .getgeo = ubd_getgeo, 117 }; 118 119 /* Protected by ubd_lock */ 120 static int fake_major = UBD_MAJOR; 121 static struct gendisk *ubd_gendisk[MAX_DEV]; 122 static struct gendisk *fake_gendisk[MAX_DEV]; 123 124 #ifdef CONFIG_BLK_DEV_UBD_SYNC 125 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 126 .cl = 1 }) 127 #else 128 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 129 .cl = 1 }) 130 #endif 131 static struct openflags global_openflags = OPEN_FLAGS; 132 133 struct cow { 134 /* backing file name */ 135 char *file; 136 /* backing file fd */ 137 int fd; 138 unsigned long *bitmap; 139 unsigned long bitmap_len; 140 int bitmap_offset; 141 int data_offset; 142 }; 143 144 #define MAX_SG 64 145 146 struct ubd { 147 /* name (and fd, below) of the file opened for writing, either the 148 * backing or the cow file. */ 149 char *file; 150 int count; 151 int fd; 152 __u64 size; 153 struct openflags boot_openflags; 154 struct openflags openflags; 155 unsigned shared:1; 156 unsigned no_cow:1; 157 unsigned no_trim:1; 158 struct cow cow; 159 struct platform_device pdev; 160 struct request_queue *queue; 161 struct blk_mq_tag_set tag_set; 162 spinlock_t lock; 163 }; 164 165 #define DEFAULT_COW { \ 166 .file = NULL, \ 167 .fd = -1, \ 168 .bitmap = NULL, \ 169 .bitmap_offset = 0, \ 170 .data_offset = 0, \ 171 } 172 173 #define DEFAULT_UBD { \ 174 .file = NULL, \ 175 .count = 0, \ 176 .fd = -1, \ 177 .size = -1, \ 178 .boot_openflags = OPEN_FLAGS, \ 179 .openflags = OPEN_FLAGS, \ 180 .no_cow = 0, \ 181 .no_trim = 0, \ 182 .shared = 0, \ 183 .cow = DEFAULT_COW, \ 184 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \ 185 } 186 187 /* Protected by ubd_lock */ 188 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD }; 189 190 /* Only changed by fake_ide_setup which is a setup */ 191 static int fake_ide = 0; 192 static struct proc_dir_entry *proc_ide_root = NULL; 193 static struct proc_dir_entry *proc_ide = NULL; 194 195 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 196 const struct blk_mq_queue_data *bd); 197 198 static void make_proc_ide(void) 199 { 200 proc_ide_root = proc_mkdir("ide", NULL); 201 proc_ide = proc_mkdir("ide0", proc_ide_root); 202 } 203 204 static int fake_ide_media_proc_show(struct seq_file *m, void *v) 205 { 206 seq_puts(m, "disk\n"); 207 return 0; 208 } 209 210 static void make_ide_entries(const char *dev_name) 211 { 212 struct proc_dir_entry *dir, *ent; 213 char name[64]; 214 215 if(proc_ide_root == NULL) make_proc_ide(); 216 217 dir = proc_mkdir(dev_name, proc_ide); 218 if(!dir) return; 219 220 ent = proc_create_single("media", S_IRUGO, dir, 221 fake_ide_media_proc_show); 222 if(!ent) return; 223 snprintf(name, sizeof(name), "ide0/%s", dev_name); 224 proc_symlink(dev_name, proc_ide_root, name); 225 } 226 227 static int fake_ide_setup(char *str) 228 { 229 fake_ide = 1; 230 return 1; 231 } 232 233 __setup("fake_ide", fake_ide_setup); 234 235 __uml_help(fake_ide_setup, 236 "fake_ide\n" 237 " Create ide0 entries that map onto ubd devices.\n\n" 238 ); 239 240 static int parse_unit(char **ptr) 241 { 242 char *str = *ptr, *end; 243 int n = -1; 244 245 if(isdigit(*str)) { 246 n = simple_strtoul(str, &end, 0); 247 if(end == str) 248 return -1; 249 *ptr = end; 250 } 251 else if (('a' <= *str) && (*str <= 'z')) { 252 n = *str - 'a'; 253 str++; 254 *ptr = str; 255 } 256 return n; 257 } 258 259 /* If *index_out == -1 at exit, the passed option was a general one; 260 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it 261 * should not be freed on exit. 262 */ 263 static int ubd_setup_common(char *str, int *index_out, char **error_out) 264 { 265 struct ubd *ubd_dev; 266 struct openflags flags = global_openflags; 267 char *backing_file; 268 int n, err = 0, i; 269 270 if(index_out) *index_out = -1; 271 n = *str; 272 if(n == '='){ 273 char *end; 274 int major; 275 276 str++; 277 if(!strcmp(str, "sync")){ 278 global_openflags = of_sync(global_openflags); 279 goto out1; 280 } 281 282 err = -EINVAL; 283 major = simple_strtoul(str, &end, 0); 284 if((*end != '\0') || (end == str)){ 285 *error_out = "Didn't parse major number"; 286 goto out1; 287 } 288 289 mutex_lock(&ubd_lock); 290 if (fake_major != UBD_MAJOR) { 291 *error_out = "Can't assign a fake major twice"; 292 goto out1; 293 } 294 295 fake_major = major; 296 297 printk(KERN_INFO "Setting extra ubd major number to %d\n", 298 major); 299 err = 0; 300 out1: 301 mutex_unlock(&ubd_lock); 302 return err; 303 } 304 305 n = parse_unit(&str); 306 if(n < 0){ 307 *error_out = "Couldn't parse device number"; 308 return -EINVAL; 309 } 310 if(n >= MAX_DEV){ 311 *error_out = "Device number out of range"; 312 return 1; 313 } 314 315 err = -EBUSY; 316 mutex_lock(&ubd_lock); 317 318 ubd_dev = &ubd_devs[n]; 319 if(ubd_dev->file != NULL){ 320 *error_out = "Device is already configured"; 321 goto out; 322 } 323 324 if (index_out) 325 *index_out = n; 326 327 err = -EINVAL; 328 for (i = 0; i < sizeof("rscdt="); i++) { 329 switch (*str) { 330 case 'r': 331 flags.w = 0; 332 break; 333 case 's': 334 flags.s = 1; 335 break; 336 case 'd': 337 ubd_dev->no_cow = 1; 338 break; 339 case 'c': 340 ubd_dev->shared = 1; 341 break; 342 case 't': 343 ubd_dev->no_trim = 1; 344 break; 345 case '=': 346 str++; 347 goto break_loop; 348 default: 349 *error_out = "Expected '=' or flag letter " 350 "(r, s, c, t or d)"; 351 goto out; 352 } 353 str++; 354 } 355 356 if (*str == '=') 357 *error_out = "Too many flags specified"; 358 else 359 *error_out = "Missing '='"; 360 goto out; 361 362 break_loop: 363 backing_file = strchr(str, ','); 364 365 if (backing_file == NULL) 366 backing_file = strchr(str, ':'); 367 368 if(backing_file != NULL){ 369 if(ubd_dev->no_cow){ 370 *error_out = "Can't specify both 'd' and a cow file"; 371 goto out; 372 } 373 else { 374 *backing_file = '\0'; 375 backing_file++; 376 } 377 } 378 err = 0; 379 ubd_dev->file = str; 380 ubd_dev->cow.file = backing_file; 381 ubd_dev->boot_openflags = flags; 382 out: 383 mutex_unlock(&ubd_lock); 384 return err; 385 } 386 387 static int ubd_setup(char *str) 388 { 389 char *error; 390 int err; 391 392 err = ubd_setup_common(str, NULL, &error); 393 if(err) 394 printk(KERN_ERR "Failed to initialize device with \"%s\" : " 395 "%s\n", str, error); 396 return 1; 397 } 398 399 __setup("ubd", ubd_setup); 400 __uml_help(ubd_setup, 401 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" 402 " This is used to associate a device with a file in the underlying\n" 403 " filesystem. When specifying two filenames, the first one is the\n" 404 " COW name and the second is the backing file name. As separator you can\n" 405 " use either a ':' or a ',': the first one allows writing things like;\n" 406 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 407 " while with a ',' the shell would not expand the 2nd '~'.\n" 408 " When using only one filename, UML will detect whether to treat it like\n" 409 " a COW file or a backing file. To override this detection, add the 'd'\n" 410 " flag:\n" 411 " ubd0d=BackingFile\n" 412 " Usually, there is a filesystem in the file, but \n" 413 " that's not required. Swap devices containing swap files can be\n" 414 " specified like this. Also, a file which doesn't contain a\n" 415 " filesystem can have its contents read in the virtual \n" 416 " machine by running 'dd' on the device. <n> must be in the range\n" 417 " 0 to 7. Appending an 'r' to the number will cause that device\n" 418 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 419 " an 's' will cause data to be written to disk on the host immediately.\n" 420 " 'c' will cause the device to be treated as being shared between multiple\n" 421 " UMLs and file locking will be turned off - this is appropriate for a\n" 422 " cluster filesystem and inappropriate at almost all other times.\n\n" 423 " 't' will disable trim/discard support on the device (enabled by default).\n\n" 424 ); 425 426 static int udb_setup(char *str) 427 { 428 printk("udb%s specified on command line is almost certainly a ubd -> " 429 "udb TYPO\n", str); 430 return 1; 431 } 432 433 __setup("udb", udb_setup); 434 __uml_help(udb_setup, 435 "udb\n" 436 " This option is here solely to catch ubd -> udb typos, which can be\n" 437 " to impossible to catch visually unless you specifically look for\n" 438 " them. The only result of any option starting with 'udb' is an error\n" 439 " in the boot output.\n\n" 440 ); 441 442 /* Only changed by ubd_init, which is an initcall. */ 443 static int thread_fd = -1; 444 445 /* Function to read several request pointers at a time 446 * handling fractional reads if (and as) needed 447 */ 448 449 static int bulk_req_safe_read( 450 int fd, 451 struct io_thread_req * (*request_buffer)[], 452 struct io_thread_req **remainder, 453 int *remainder_size, 454 int max_recs 455 ) 456 { 457 int n = 0; 458 int res = 0; 459 460 if (*remainder_size > 0) { 461 memmove( 462 (char *) request_buffer, 463 (char *) remainder, *remainder_size 464 ); 465 n = *remainder_size; 466 } 467 468 res = os_read_file( 469 fd, 470 ((char *) request_buffer) + *remainder_size, 471 sizeof(struct io_thread_req *)*max_recs 472 - *remainder_size 473 ); 474 if (res > 0) { 475 n += res; 476 if ((n % sizeof(struct io_thread_req *)) > 0) { 477 /* 478 * Read somehow returned not a multiple of dword 479 * theoretically possible, but never observed in the 480 * wild, so read routine must be able to handle it 481 */ 482 *remainder_size = n % sizeof(struct io_thread_req *); 483 WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); 484 memmove( 485 remainder, 486 ((char *) request_buffer) + 487 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), 488 *remainder_size 489 ); 490 n = n - *remainder_size; 491 } 492 } else { 493 n = res; 494 } 495 return n; 496 } 497 498 /* Called without dev->lock held, and only in interrupt context. */ 499 static void ubd_handler(void) 500 { 501 int n; 502 int count; 503 504 while(1){ 505 n = bulk_req_safe_read( 506 thread_fd, 507 irq_req_buffer, 508 &irq_remainder, 509 &irq_remainder_size, 510 UBD_REQ_BUFFER_SIZE 511 ); 512 if (n < 0) { 513 if(n == -EAGAIN) 514 break; 515 printk(KERN_ERR "spurious interrupt in ubd_handler, " 516 "err = %d\n", -n); 517 return; 518 } 519 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 520 struct io_thread_req *io_req = (*irq_req_buffer)[count]; 521 522 if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) { 523 blk_queue_max_discard_sectors(io_req->req->q, 0); 524 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0); 525 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q); 526 } 527 if ((io_req->error) || (io_req->buffer == NULL)) 528 blk_mq_end_request(io_req->req, io_req->error); 529 else { 530 if (!blk_update_request(io_req->req, io_req->error, io_req->length)) 531 __blk_mq_end_request(io_req->req, io_req->error); 532 } 533 kfree(io_req); 534 } 535 } 536 } 537 538 static irqreturn_t ubd_intr(int irq, void *dev) 539 { 540 ubd_handler(); 541 return IRQ_HANDLED; 542 } 543 544 /* Only changed by ubd_init, which is an initcall. */ 545 static int io_pid = -1; 546 547 static void kill_io_thread(void) 548 { 549 if(io_pid != -1) 550 os_kill_process(io_pid, 1); 551 } 552 553 __uml_exitcall(kill_io_thread); 554 555 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) 556 { 557 char *file; 558 int fd; 559 int err; 560 561 __u32 version; 562 __u32 align; 563 char *backing_file; 564 time_t mtime; 565 unsigned long long size; 566 int sector_size; 567 int bitmap_offset; 568 569 if (ubd_dev->file && ubd_dev->cow.file) { 570 file = ubd_dev->cow.file; 571 572 goto out; 573 } 574 575 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); 576 if (fd < 0) 577 return fd; 578 579 err = read_cow_header(file_reader, &fd, &version, &backing_file, \ 580 &mtime, &size, §or_size, &align, &bitmap_offset); 581 os_close_file(fd); 582 583 if(err == -EINVAL) 584 file = ubd_dev->file; 585 else 586 file = backing_file; 587 588 out: 589 return os_file_size(file, size_out); 590 } 591 592 static int read_cow_bitmap(int fd, void *buf, int offset, int len) 593 { 594 int err; 595 596 err = os_pread_file(fd, buf, len, offset); 597 if (err < 0) 598 return err; 599 600 return 0; 601 } 602 603 static int backing_file_mismatch(char *file, __u64 size, time_t mtime) 604 { 605 unsigned long modtime; 606 unsigned long long actual; 607 int err; 608 609 err = os_file_modtime(file, &modtime); 610 if (err < 0) { 611 printk(KERN_ERR "Failed to get modification time of backing " 612 "file \"%s\", err = %d\n", file, -err); 613 return err; 614 } 615 616 err = os_file_size(file, &actual); 617 if (err < 0) { 618 printk(KERN_ERR "Failed to get size of backing file \"%s\", " 619 "err = %d\n", file, -err); 620 return err; 621 } 622 623 if (actual != size) { 624 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 625 * the typecast.*/ 626 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " 627 "vs backing file\n", (unsigned long long) size, actual); 628 return -EINVAL; 629 } 630 if (modtime != mtime) { 631 printk(KERN_ERR "mtime mismatch (%ld vs %ld) of COW header vs " 632 "backing file\n", mtime, modtime); 633 return -EINVAL; 634 } 635 return 0; 636 } 637 638 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) 639 { 640 struct uml_stat buf1, buf2; 641 int err; 642 643 if (from_cmdline == NULL) 644 return 0; 645 if (!strcmp(from_cmdline, from_cow)) 646 return 0; 647 648 err = os_stat_file(from_cmdline, &buf1); 649 if (err < 0) { 650 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, 651 -err); 652 return 0; 653 } 654 err = os_stat_file(from_cow, &buf2); 655 if (err < 0) { 656 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow, 657 -err); 658 return 1; 659 } 660 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 661 return 0; 662 663 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, " 664 "\"%s\" specified in COW header of \"%s\"\n", 665 from_cmdline, from_cow, cow); 666 return 1; 667 } 668 669 static int open_ubd_file(char *file, struct openflags *openflags, int shared, 670 char **backing_file_out, int *bitmap_offset_out, 671 unsigned long *bitmap_len_out, int *data_offset_out, 672 int *create_cow_out) 673 { 674 time_t mtime; 675 unsigned long long size; 676 __u32 version, align; 677 char *backing_file; 678 int fd, err, sectorsize, asked_switch, mode = 0644; 679 680 fd = os_open_file(file, *openflags, mode); 681 if (fd < 0) { 682 if ((fd == -ENOENT) && (create_cow_out != NULL)) 683 *create_cow_out = 1; 684 if (!openflags->w || 685 ((fd != -EROFS) && (fd != -EACCES))) 686 return fd; 687 openflags->w = 0; 688 fd = os_open_file(file, *openflags, mode); 689 if (fd < 0) 690 return fd; 691 } 692 693 if (shared) 694 printk(KERN_INFO "Not locking \"%s\" on the host\n", file); 695 else { 696 err = os_lock_file(fd, openflags->w); 697 if (err < 0) { 698 printk(KERN_ERR "Failed to lock '%s', err = %d\n", 699 file, -err); 700 goto out_close; 701 } 702 } 703 704 /* Successful return case! */ 705 if (backing_file_out == NULL) 706 return fd; 707 708 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 709 &size, §orsize, &align, bitmap_offset_out); 710 if (err && (*backing_file_out != NULL)) { 711 printk(KERN_ERR "Failed to read COW header from COW file " 712 "\"%s\", errno = %d\n", file, -err); 713 goto out_close; 714 } 715 if (err) 716 return fd; 717 718 asked_switch = path_requires_switch(*backing_file_out, backing_file, 719 file); 720 721 /* Allow switching only if no mismatch. */ 722 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, 723 mtime)) { 724 printk(KERN_ERR "Switching backing file to '%s'\n", 725 *backing_file_out); 726 err = write_cow_header(file, fd, *backing_file_out, 727 sectorsize, align, &size); 728 if (err) { 729 printk(KERN_ERR "Switch failed, errno = %d\n", -err); 730 goto out_close; 731 } 732 } else { 733 *backing_file_out = backing_file; 734 err = backing_file_mismatch(*backing_file_out, size, mtime); 735 if (err) 736 goto out_close; 737 } 738 739 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 740 bitmap_len_out, data_offset_out); 741 742 return fd; 743 out_close: 744 os_close_file(fd); 745 return err; 746 } 747 748 static int create_cow_file(char *cow_file, char *backing_file, 749 struct openflags flags, 750 int sectorsize, int alignment, int *bitmap_offset_out, 751 unsigned long *bitmap_len_out, int *data_offset_out) 752 { 753 int err, fd; 754 755 flags.c = 1; 756 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); 757 if (fd < 0) { 758 err = fd; 759 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n", 760 cow_file, -err); 761 goto out; 762 } 763 764 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 765 bitmap_offset_out, bitmap_len_out, 766 data_offset_out); 767 if (!err) 768 return fd; 769 os_close_file(fd); 770 out: 771 return err; 772 } 773 774 static void ubd_close_dev(struct ubd *ubd_dev) 775 { 776 os_close_file(ubd_dev->fd); 777 if(ubd_dev->cow.file == NULL) 778 return; 779 780 os_close_file(ubd_dev->cow.fd); 781 vfree(ubd_dev->cow.bitmap); 782 ubd_dev->cow.bitmap = NULL; 783 } 784 785 static int ubd_open_dev(struct ubd *ubd_dev) 786 { 787 struct openflags flags; 788 char **back_ptr; 789 int err, create_cow, *create_ptr; 790 int fd; 791 792 ubd_dev->openflags = ubd_dev->boot_openflags; 793 create_cow = 0; 794 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; 795 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; 796 797 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, 798 back_ptr, &ubd_dev->cow.bitmap_offset, 799 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, 800 create_ptr); 801 802 if((fd == -ENOENT) && create_cow){ 803 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, 804 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE, 805 &ubd_dev->cow.bitmap_offset, 806 &ubd_dev->cow.bitmap_len, 807 &ubd_dev->cow.data_offset); 808 if(fd >= 0){ 809 printk(KERN_INFO "Creating \"%s\" as COW file for " 810 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); 811 } 812 } 813 814 if(fd < 0){ 815 printk("Failed to open '%s', errno = %d\n", ubd_dev->file, 816 -fd); 817 return fd; 818 } 819 ubd_dev->fd = fd; 820 821 if(ubd_dev->cow.file != NULL){ 822 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long)); 823 824 err = -ENOMEM; 825 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len); 826 if(ubd_dev->cow.bitmap == NULL){ 827 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 828 goto error; 829 } 830 flush_tlb_kernel_vm(); 831 832 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, 833 ubd_dev->cow.bitmap_offset, 834 ubd_dev->cow.bitmap_len); 835 if(err < 0) 836 goto error; 837 838 flags = ubd_dev->openflags; 839 flags.w = 0; 840 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, 841 NULL, NULL, NULL, NULL); 842 if(err < 0) goto error; 843 ubd_dev->cow.fd = err; 844 } 845 if (ubd_dev->no_trim == 0) { 846 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE; 847 ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE; 848 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST); 849 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST); 850 blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue); 851 } 852 blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue); 853 return 0; 854 error: 855 os_close_file(ubd_dev->fd); 856 return err; 857 } 858 859 static void ubd_device_release(struct device *dev) 860 { 861 struct ubd *ubd_dev = dev_get_drvdata(dev); 862 863 blk_cleanup_queue(ubd_dev->queue); 864 blk_mq_free_tag_set(&ubd_dev->tag_set); 865 *ubd_dev = ((struct ubd) DEFAULT_UBD); 866 } 867 868 static int ubd_disk_register(int major, u64 size, int unit, 869 struct gendisk **disk_out) 870 { 871 struct device *parent = NULL; 872 struct gendisk *disk; 873 874 disk = alloc_disk(1 << UBD_SHIFT); 875 if(disk == NULL) 876 return -ENOMEM; 877 878 disk->major = major; 879 disk->first_minor = unit << UBD_SHIFT; 880 disk->fops = &ubd_blops; 881 set_capacity(disk, size / 512); 882 if (major == UBD_MAJOR) 883 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 884 else 885 sprintf(disk->disk_name, "ubd_fake%d", unit); 886 887 /* sysfs register (not for ide fake devices) */ 888 if (major == UBD_MAJOR) { 889 ubd_devs[unit].pdev.id = unit; 890 ubd_devs[unit].pdev.name = DRIVER_NAME; 891 ubd_devs[unit].pdev.dev.release = ubd_device_release; 892 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]); 893 platform_device_register(&ubd_devs[unit].pdev); 894 parent = &ubd_devs[unit].pdev.dev; 895 } 896 897 disk->private_data = &ubd_devs[unit]; 898 disk->queue = ubd_devs[unit].queue; 899 device_add_disk(parent, disk, NULL); 900 901 *disk_out = disk; 902 return 0; 903 } 904 905 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE)) 906 907 static const struct blk_mq_ops ubd_mq_ops = { 908 .queue_rq = ubd_queue_rq, 909 }; 910 911 static int ubd_add(int n, char **error_out) 912 { 913 struct ubd *ubd_dev = &ubd_devs[n]; 914 int err = 0; 915 916 if(ubd_dev->file == NULL) 917 goto out; 918 919 err = ubd_file_size(ubd_dev, &ubd_dev->size); 920 if(err < 0){ 921 *error_out = "Couldn't determine size of device's file"; 922 goto out; 923 } 924 925 ubd_dev->size = ROUND_BLOCK(ubd_dev->size); 926 927 ubd_dev->tag_set.ops = &ubd_mq_ops; 928 ubd_dev->tag_set.queue_depth = 64; 929 ubd_dev->tag_set.numa_node = NUMA_NO_NODE; 930 ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 931 ubd_dev->tag_set.driver_data = ubd_dev; 932 ubd_dev->tag_set.nr_hw_queues = 1; 933 934 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set); 935 if (err) 936 goto out; 937 938 ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set); 939 if (IS_ERR(ubd_dev->queue)) { 940 err = PTR_ERR(ubd_dev->queue); 941 goto out_cleanup_tags; 942 } 943 944 ubd_dev->queue->queuedata = ubd_dev; 945 blk_queue_write_cache(ubd_dev->queue, true, false); 946 947 blk_queue_max_segments(ubd_dev->queue, MAX_SG); 948 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]); 949 if(err){ 950 *error_out = "Failed to register device"; 951 goto out_cleanup_tags; 952 } 953 954 if (fake_major != UBD_MAJOR) 955 ubd_disk_register(fake_major, ubd_dev->size, n, 956 &fake_gendisk[n]); 957 958 /* 959 * Perhaps this should also be under the "if (fake_major)" above 960 * using the fake_disk->disk_name 961 */ 962 if (fake_ide) 963 make_ide_entries(ubd_gendisk[n]->disk_name); 964 965 err = 0; 966 out: 967 return err; 968 969 out_cleanup_tags: 970 blk_mq_free_tag_set(&ubd_dev->tag_set); 971 if (!(IS_ERR(ubd_dev->queue))) 972 blk_cleanup_queue(ubd_dev->queue); 973 goto out; 974 } 975 976 static int ubd_config(char *str, char **error_out) 977 { 978 int n, ret; 979 980 /* This string is possibly broken up and stored, so it's only 981 * freed if ubd_setup_common fails, or if only general options 982 * were set. 983 */ 984 str = kstrdup(str, GFP_KERNEL); 985 if (str == NULL) { 986 *error_out = "Failed to allocate memory"; 987 return -ENOMEM; 988 } 989 990 ret = ubd_setup_common(str, &n, error_out); 991 if (ret) 992 goto err_free; 993 994 if (n == -1) { 995 ret = 0; 996 goto err_free; 997 } 998 999 mutex_lock(&ubd_lock); 1000 ret = ubd_add(n, error_out); 1001 if (ret) 1002 ubd_devs[n].file = NULL; 1003 mutex_unlock(&ubd_lock); 1004 1005 out: 1006 return ret; 1007 1008 err_free: 1009 kfree(str); 1010 goto out; 1011 } 1012 1013 static int ubd_get_config(char *name, char *str, int size, char **error_out) 1014 { 1015 struct ubd *ubd_dev; 1016 int n, len = 0; 1017 1018 n = parse_unit(&name); 1019 if((n >= MAX_DEV) || (n < 0)){ 1020 *error_out = "ubd_get_config : device number out of range"; 1021 return -1; 1022 } 1023 1024 ubd_dev = &ubd_devs[n]; 1025 mutex_lock(&ubd_lock); 1026 1027 if(ubd_dev->file == NULL){ 1028 CONFIG_CHUNK(str, size, len, "", 1); 1029 goto out; 1030 } 1031 1032 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); 1033 1034 if(ubd_dev->cow.file != NULL){ 1035 CONFIG_CHUNK(str, size, len, ",", 0); 1036 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); 1037 } 1038 else CONFIG_CHUNK(str, size, len, "", 1); 1039 1040 out: 1041 mutex_unlock(&ubd_lock); 1042 return len; 1043 } 1044 1045 static int ubd_id(char **str, int *start_out, int *end_out) 1046 { 1047 int n; 1048 1049 n = parse_unit(str); 1050 *start_out = 0; 1051 *end_out = MAX_DEV - 1; 1052 return n; 1053 } 1054 1055 static int ubd_remove(int n, char **error_out) 1056 { 1057 struct gendisk *disk = ubd_gendisk[n]; 1058 struct ubd *ubd_dev; 1059 int err = -ENODEV; 1060 1061 mutex_lock(&ubd_lock); 1062 1063 ubd_dev = &ubd_devs[n]; 1064 1065 if(ubd_dev->file == NULL) 1066 goto out; 1067 1068 /* you cannot remove a open disk */ 1069 err = -EBUSY; 1070 if(ubd_dev->count > 0) 1071 goto out; 1072 1073 ubd_gendisk[n] = NULL; 1074 if(disk != NULL){ 1075 del_gendisk(disk); 1076 put_disk(disk); 1077 } 1078 1079 if(fake_gendisk[n] != NULL){ 1080 del_gendisk(fake_gendisk[n]); 1081 put_disk(fake_gendisk[n]); 1082 fake_gendisk[n] = NULL; 1083 } 1084 1085 err = 0; 1086 platform_device_unregister(&ubd_dev->pdev); 1087 out: 1088 mutex_unlock(&ubd_lock); 1089 return err; 1090 } 1091 1092 /* All these are called by mconsole in process context and without 1093 * ubd-specific locks. The structure itself is const except for .list. 1094 */ 1095 static struct mc_device ubd_mc = { 1096 .list = LIST_HEAD_INIT(ubd_mc.list), 1097 .name = "ubd", 1098 .config = ubd_config, 1099 .get_config = ubd_get_config, 1100 .id = ubd_id, 1101 .remove = ubd_remove, 1102 }; 1103 1104 static int __init ubd_mc_init(void) 1105 { 1106 mconsole_register_dev(&ubd_mc); 1107 return 0; 1108 } 1109 1110 __initcall(ubd_mc_init); 1111 1112 static int __init ubd0_init(void) 1113 { 1114 struct ubd *ubd_dev = &ubd_devs[0]; 1115 1116 mutex_lock(&ubd_lock); 1117 if(ubd_dev->file == NULL) 1118 ubd_dev->file = "root_fs"; 1119 mutex_unlock(&ubd_lock); 1120 1121 return 0; 1122 } 1123 1124 __initcall(ubd0_init); 1125 1126 /* Used in ubd_init, which is an initcall */ 1127 static struct platform_driver ubd_driver = { 1128 .driver = { 1129 .name = DRIVER_NAME, 1130 }, 1131 }; 1132 1133 static int __init ubd_init(void) 1134 { 1135 char *error; 1136 int i, err; 1137 1138 if (register_blkdev(UBD_MAJOR, "ubd")) 1139 return -1; 1140 1141 if (fake_major != UBD_MAJOR) { 1142 char name[sizeof("ubd_nnn\0")]; 1143 1144 snprintf(name, sizeof(name), "ubd_%d", fake_major); 1145 if (register_blkdev(fake_major, "ubd")) 1146 return -1; 1147 } 1148 1149 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1150 sizeof(struct io_thread_req *), 1151 GFP_KERNEL 1152 ); 1153 irq_remainder = 0; 1154 1155 if (irq_req_buffer == NULL) { 1156 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1157 return -1; 1158 } 1159 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, 1160 sizeof(struct io_thread_req *), 1161 GFP_KERNEL 1162 ); 1163 1164 io_remainder = 0; 1165 1166 if (io_req_buffer == NULL) { 1167 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1168 return -1; 1169 } 1170 platform_driver_register(&ubd_driver); 1171 mutex_lock(&ubd_lock); 1172 for (i = 0; i < MAX_DEV; i++){ 1173 err = ubd_add(i, &error); 1174 if(err) 1175 printk(KERN_ERR "Failed to initialize ubd device %d :" 1176 "%s\n", i, error); 1177 } 1178 mutex_unlock(&ubd_lock); 1179 return 0; 1180 } 1181 1182 late_initcall(ubd_init); 1183 1184 static int __init ubd_driver_init(void){ 1185 unsigned long stack; 1186 int err; 1187 1188 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 1189 if(global_openflags.s){ 1190 printk(KERN_INFO "ubd: Synchronous mode\n"); 1191 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 1192 * enough. So use anyway the io thread. */ 1193 } 1194 stack = alloc_stack(0, 0); 1195 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), 1196 &thread_fd); 1197 if(io_pid < 0){ 1198 printk(KERN_ERR 1199 "ubd : Failed to start I/O thread (errno = %d) - " 1200 "falling back to synchronous I/O\n", -io_pid); 1201 io_pid = -1; 1202 return 0; 1203 } 1204 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 1205 0, "ubd", ubd_devs); 1206 if(err != 0) 1207 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 1208 return 0; 1209 } 1210 1211 device_initcall(ubd_driver_init); 1212 1213 static int ubd_open(struct block_device *bdev, fmode_t mode) 1214 { 1215 struct gendisk *disk = bdev->bd_disk; 1216 struct ubd *ubd_dev = disk->private_data; 1217 int err = 0; 1218 1219 mutex_lock(&ubd_mutex); 1220 if(ubd_dev->count == 0){ 1221 err = ubd_open_dev(ubd_dev); 1222 if(err){ 1223 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 1224 disk->disk_name, ubd_dev->file, -err); 1225 goto out; 1226 } 1227 } 1228 ubd_dev->count++; 1229 set_disk_ro(disk, !ubd_dev->openflags.w); 1230 1231 /* This should no more be needed. And it didn't work anyway to exclude 1232 * read-write remounting of filesystems.*/ 1233 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){ 1234 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); 1235 err = -EROFS; 1236 }*/ 1237 out: 1238 mutex_unlock(&ubd_mutex); 1239 return err; 1240 } 1241 1242 static void ubd_release(struct gendisk *disk, fmode_t mode) 1243 { 1244 struct ubd *ubd_dev = disk->private_data; 1245 1246 mutex_lock(&ubd_mutex); 1247 if(--ubd_dev->count == 0) 1248 ubd_close_dev(ubd_dev); 1249 mutex_unlock(&ubd_mutex); 1250 } 1251 1252 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 1253 __u64 *cow_offset, unsigned long *bitmap, 1254 __u64 bitmap_offset, unsigned long *bitmap_words, 1255 __u64 bitmap_len) 1256 { 1257 __u64 sector = io_offset >> SECTOR_SHIFT; 1258 int i, update_bitmap = 0; 1259 1260 for (i = 0; i < length >> SECTOR_SHIFT; i++) { 1261 if(cow_mask != NULL) 1262 ubd_set_bit(i, (unsigned char *) cow_mask); 1263 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1264 continue; 1265 1266 update_bitmap = 1; 1267 ubd_set_bit(sector + i, (unsigned char *) bitmap); 1268 } 1269 1270 if(!update_bitmap) 1271 return; 1272 1273 *cow_offset = sector / (sizeof(unsigned long) * 8); 1274 1275 /* This takes care of the case where we're exactly at the end of the 1276 * device, and *cow_offset + 1 is off the end. So, just back it up 1277 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 1278 * for the original diagnosis. 1279 */ 1280 if (*cow_offset == (DIV_ROUND_UP(bitmap_len, 1281 sizeof(unsigned long)) - 1)) 1282 (*cow_offset)--; 1283 1284 bitmap_words[0] = bitmap[*cow_offset]; 1285 bitmap_words[1] = bitmap[*cow_offset + 1]; 1286 1287 *cow_offset *= sizeof(unsigned long); 1288 *cow_offset += bitmap_offset; 1289 } 1290 1291 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, 1292 __u64 bitmap_offset, __u64 bitmap_len) 1293 { 1294 __u64 sector = req->offset >> SECTOR_SHIFT; 1295 int i; 1296 1297 if (req->length > (sizeof(req->sector_mask) * 8) << SECTOR_SHIFT) 1298 panic("Operation too long"); 1299 1300 if (req_op(req->req) == REQ_OP_READ) { 1301 for (i = 0; i < req->length >> SECTOR_SHIFT; i++) { 1302 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1303 ubd_set_bit(i, (unsigned char *) 1304 &req->sector_mask); 1305 } 1306 } 1307 else cowify_bitmap(req->offset, req->length, &req->sector_mask, 1308 &req->cow_offset, bitmap, bitmap_offset, 1309 req->bitmap_words, bitmap_len); 1310 } 1311 1312 static int ubd_queue_one_vec(struct blk_mq_hw_ctx *hctx, struct request *req, 1313 u64 off, struct bio_vec *bvec) 1314 { 1315 struct ubd *dev = hctx->queue->queuedata; 1316 struct io_thread_req *io_req; 1317 int ret; 1318 1319 io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC); 1320 if (!io_req) 1321 return -ENOMEM; 1322 1323 io_req->req = req; 1324 if (dev->cow.file) 1325 io_req->fds[0] = dev->cow.fd; 1326 else 1327 io_req->fds[0] = dev->fd; 1328 io_req->error = 0; 1329 1330 if (bvec != NULL) { 1331 io_req->buffer = page_address(bvec->bv_page) + bvec->bv_offset; 1332 io_req->length = bvec->bv_len; 1333 } else { 1334 io_req->buffer = NULL; 1335 io_req->length = blk_rq_bytes(req); 1336 } 1337 1338 io_req->sectorsize = SECTOR_SIZE; 1339 io_req->fds[1] = dev->fd; 1340 io_req->cow_offset = -1; 1341 io_req->offset = off; 1342 io_req->sector_mask = 0; 1343 io_req->offsets[0] = 0; 1344 io_req->offsets[1] = dev->cow.data_offset; 1345 1346 if (dev->cow.file) 1347 cowify_req(io_req, dev->cow.bitmap, 1348 dev->cow.bitmap_offset, dev->cow.bitmap_len); 1349 1350 ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); 1351 if (ret != sizeof(io_req)) { 1352 if (ret != -EAGAIN) 1353 pr_err("write to io thread failed: %d\n", -ret); 1354 kfree(io_req); 1355 } 1356 return ret; 1357 } 1358 1359 static int queue_rw_req(struct blk_mq_hw_ctx *hctx, struct request *req) 1360 { 1361 struct req_iterator iter; 1362 struct bio_vec bvec; 1363 int ret; 1364 u64 off = (u64)blk_rq_pos(req) << SECTOR_SHIFT; 1365 1366 rq_for_each_segment(bvec, req, iter) { 1367 ret = ubd_queue_one_vec(hctx, req, off, &bvec); 1368 if (ret < 0) 1369 return ret; 1370 off += bvec.bv_len; 1371 } 1372 return 0; 1373 } 1374 1375 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, 1376 const struct blk_mq_queue_data *bd) 1377 { 1378 struct ubd *ubd_dev = hctx->queue->queuedata; 1379 struct request *req = bd->rq; 1380 int ret = 0, res = BLK_STS_OK; 1381 1382 blk_mq_start_request(req); 1383 1384 spin_lock_irq(&ubd_dev->lock); 1385 1386 switch (req_op(req)) { 1387 /* operations with no lentgth/offset arguments */ 1388 case REQ_OP_FLUSH: 1389 ret = ubd_queue_one_vec(hctx, req, 0, NULL); 1390 break; 1391 case REQ_OP_READ: 1392 case REQ_OP_WRITE: 1393 ret = queue_rw_req(hctx, req); 1394 break; 1395 case REQ_OP_DISCARD: 1396 case REQ_OP_WRITE_ZEROES: 1397 ret = ubd_queue_one_vec(hctx, req, (u64)blk_rq_pos(req) << 9, NULL); 1398 break; 1399 default: 1400 WARN_ON_ONCE(1); 1401 res = BLK_STS_NOTSUPP; 1402 } 1403 1404 spin_unlock_irq(&ubd_dev->lock); 1405 1406 if (ret < 0) 1407 blk_mq_requeue_request(req, true); 1408 1409 return res; 1410 } 1411 1412 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) 1413 { 1414 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1415 1416 geo->heads = 128; 1417 geo->sectors = 32; 1418 geo->cylinders = ubd_dev->size / (128 * 32 * 512); 1419 return 0; 1420 } 1421 1422 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 1423 unsigned int cmd, unsigned long arg) 1424 { 1425 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1426 u16 ubd_id[ATA_ID_WORDS]; 1427 1428 switch (cmd) { 1429 struct cdrom_volctrl volume; 1430 case HDIO_GET_IDENTITY: 1431 memset(&ubd_id, 0, ATA_ID_WORDS * 2); 1432 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); 1433 ubd_id[ATA_ID_HEADS] = 128; 1434 ubd_id[ATA_ID_SECTORS] = 32; 1435 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1436 sizeof(ubd_id))) 1437 return -EFAULT; 1438 return 0; 1439 1440 case CDROMVOLREAD: 1441 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1442 return -EFAULT; 1443 volume.channel0 = 255; 1444 volume.channel1 = 255; 1445 volume.channel2 = 255; 1446 volume.channel3 = 255; 1447 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1448 return -EFAULT; 1449 return 0; 1450 } 1451 return -EINVAL; 1452 } 1453 1454 static int map_error(int error_code) 1455 { 1456 switch (error_code) { 1457 case 0: 1458 return BLK_STS_OK; 1459 case ENOSYS: 1460 case EOPNOTSUPP: 1461 return BLK_STS_NOTSUPP; 1462 case ENOSPC: 1463 return BLK_STS_NOSPC; 1464 } 1465 return BLK_STS_IOERR; 1466 } 1467 1468 /* 1469 * Everything from here onwards *IS NOT PART OF THE KERNEL* 1470 * 1471 * The following functions are part of UML hypervisor code. 1472 * All functions from here onwards are executed as a helper 1473 * thread and are not allowed to execute any kernel functions. 1474 * 1475 * Any communication must occur strictly via shared memory and IPC. 1476 * 1477 * Do not add printks, locks, kernel memory operations, etc - it 1478 * will result in unpredictable behaviour and/or crashes. 1479 */ 1480 1481 static int update_bitmap(struct io_thread_req *req) 1482 { 1483 int n; 1484 1485 if(req->cow_offset == -1) 1486 return map_error(0); 1487 1488 n = os_pwrite_file(req->fds[1], &req->bitmap_words, 1489 sizeof(req->bitmap_words), req->cow_offset); 1490 if (n != sizeof(req->bitmap_words)) 1491 return map_error(-n); 1492 1493 return map_error(0); 1494 } 1495 1496 static void do_io(struct io_thread_req *req) 1497 { 1498 char *buf = NULL; 1499 unsigned long len; 1500 int n, nsectors, start, end, bit; 1501 __u64 off; 1502 1503 /* FLUSH is really a special case, we cannot "case" it with others */ 1504 1505 if (req_op(req->req) == REQ_OP_FLUSH) { 1506 /* fds[0] is always either the rw image or our cow file */ 1507 req->error = map_error(-os_sync_file(req->fds[0])); 1508 return; 1509 } 1510 1511 nsectors = req->length / req->sectorsize; 1512 start = 0; 1513 do { 1514 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); 1515 end = start; 1516 while((end < nsectors) && 1517 (ubd_test_bit(end, (unsigned char *) 1518 &req->sector_mask) == bit)) 1519 end++; 1520 1521 off = req->offset + req->offsets[bit] + 1522 start * req->sectorsize; 1523 len = (end - start) * req->sectorsize; 1524 if (req->buffer != NULL) 1525 buf = &req->buffer[start * req->sectorsize]; 1526 1527 switch (req_op(req->req)) { 1528 case REQ_OP_READ: 1529 n = 0; 1530 do { 1531 buf = &buf[n]; 1532 len -= n; 1533 n = os_pread_file(req->fds[bit], buf, len, off); 1534 if (n < 0) { 1535 req->error = map_error(-n); 1536 return; 1537 } 1538 } while((n < len) && (n != 0)); 1539 if (n < len) memset(&buf[n], 0, len - n); 1540 break; 1541 case REQ_OP_WRITE: 1542 n = os_pwrite_file(req->fds[bit], buf, len, off); 1543 if(n != len){ 1544 req->error = map_error(-n); 1545 return; 1546 } 1547 break; 1548 case REQ_OP_DISCARD: 1549 case REQ_OP_WRITE_ZEROES: 1550 n = os_falloc_punch(req->fds[bit], off, len); 1551 if (n) { 1552 req->error = map_error(-n); 1553 return; 1554 } 1555 break; 1556 default: 1557 WARN_ON_ONCE(1); 1558 req->error = BLK_STS_NOTSUPP; 1559 return; 1560 } 1561 1562 start = end; 1563 } while(start < nsectors); 1564 1565 req->error = update_bitmap(req); 1566 } 1567 1568 /* Changed in start_io_thread, which is serialized by being called only 1569 * from ubd_init, which is an initcall. 1570 */ 1571 int kernel_fd = -1; 1572 1573 /* Only changed by the io thread. XXX: currently unused. */ 1574 static int io_count = 0; 1575 1576 int io_thread(void *arg) 1577 { 1578 int n, count, written, res; 1579 1580 os_fix_helper_signals(); 1581 1582 while(1){ 1583 n = bulk_req_safe_read( 1584 kernel_fd, 1585 io_req_buffer, 1586 &io_remainder, 1587 &io_remainder_size, 1588 UBD_REQ_BUFFER_SIZE 1589 ); 1590 if (n < 0) { 1591 if (n == -EAGAIN) { 1592 ubd_read_poll(-1); 1593 continue; 1594 } 1595 } 1596 1597 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 1598 io_count++; 1599 do_io((*io_req_buffer)[count]); 1600 } 1601 1602 written = 0; 1603 1604 do { 1605 res = os_write_file(kernel_fd, ((char *) io_req_buffer) + written, n); 1606 if (res >= 0) { 1607 written += res; 1608 } 1609 if (written < n) { 1610 ubd_write_poll(-1); 1611 } 1612 } while (written < n); 1613 } 1614 1615 return 0; 1616 } 1617