1 /* 2 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) 3 * Licensed under the GPL 4 */ 5 6 /* 2001-09-28...2002-04-17 7 * Partition stuff by James_McMechan@hotmail.com 8 * old style ubd by setting UBD_SHIFT to 0 9 * 2002-09-27...2002-10-18 massive tinkering for 2.5 10 * partitions have changed in 2.5 11 * 2003-01-29 more tinkering for 2.5.59-1 12 * This should now address the sysfs problems and has 13 * the symlink for devfs to allow for booting with 14 * the common /dev/ubd/discX/... names rather than 15 * only /dev/ubdN/discN this version also has lots of 16 * clean ups preparing for ubd-many. 17 * James McMechan 18 */ 19 20 #define MAJOR_NR UBD_MAJOR 21 #define UBD_SHIFT 4 22 23 #include "linux/config.h" 24 #include "linux/module.h" 25 #include "linux/blkdev.h" 26 #include "linux/hdreg.h" 27 #include "linux/init.h" 28 #include "linux/devfs_fs_kernel.h" 29 #include "linux/cdrom.h" 30 #include "linux/proc_fs.h" 31 #include "linux/ctype.h" 32 #include "linux/capability.h" 33 #include "linux/mm.h" 34 #include "linux/vmalloc.h" 35 #include "linux/blkpg.h" 36 #include "linux/genhd.h" 37 #include "linux/spinlock.h" 38 #include "linux/platform_device.h" 39 #include "asm/segment.h" 40 #include "asm/uaccess.h" 41 #include "asm/irq.h" 42 #include "asm/types.h" 43 #include "asm/tlbflush.h" 44 #include "user_util.h" 45 #include "mem_user.h" 46 #include "kern_util.h" 47 #include "kern.h" 48 #include "mconsole_kern.h" 49 #include "init.h" 50 #include "irq_user.h" 51 #include "irq_kern.h" 52 #include "ubd_user.h" 53 #include "os.h" 54 #include "mem.h" 55 #include "mem_kern.h" 56 #include "cow.h" 57 58 enum ubd_req { UBD_READ, UBD_WRITE }; 59 60 struct io_thread_req { 61 enum ubd_req op; 62 int fds[2]; 63 unsigned long offsets[2]; 64 unsigned long long offset; 65 unsigned long length; 66 char *buffer; 67 int sectorsize; 68 unsigned long sector_mask; 69 unsigned long long cow_offset; 70 unsigned long bitmap_words[2]; 71 int error; 72 }; 73 74 extern int open_ubd_file(char *file, struct openflags *openflags, int shared, 75 char **backing_file_out, int *bitmap_offset_out, 76 unsigned long *bitmap_len_out, int *data_offset_out, 77 int *create_cow_out); 78 extern int create_cow_file(char *cow_file, char *backing_file, 79 struct openflags flags, int sectorsize, 80 int alignment, int *bitmap_offset_out, 81 unsigned long *bitmap_len_out, 82 int *data_offset_out); 83 extern int read_cow_bitmap(int fd, void *buf, int offset, int len); 84 extern void do_io(struct io_thread_req *req); 85 86 static inline int ubd_test_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 return((data[n] & (1 << off)) != 0); 95 } 96 97 static inline void ubd_set_bit(__u64 bit, unsigned char *data) 98 { 99 __u64 n; 100 int bits, off; 101 102 bits = sizeof(data[0]) * 8; 103 n = bit / bits; 104 off = bit % bits; 105 data[n] |= (1 << off); 106 } 107 /*End stuff from ubd_user.h*/ 108 109 #define DRIVER_NAME "uml-blkdev" 110 111 static DEFINE_SPINLOCK(ubd_io_lock); 112 static DEFINE_SPINLOCK(ubd_lock); 113 114 static void (*do_ubd)(void); 115 116 static int ubd_open(struct inode * inode, struct file * filp); 117 static int ubd_release(struct inode * inode, struct file * file); 118 static int ubd_ioctl(struct inode * inode, struct file * file, 119 unsigned int cmd, unsigned long arg); 120 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); 121 122 #define MAX_DEV (8) 123 124 static struct block_device_operations ubd_blops = { 125 .owner = THIS_MODULE, 126 .open = ubd_open, 127 .release = ubd_release, 128 .ioctl = ubd_ioctl, 129 .getgeo = ubd_getgeo, 130 }; 131 132 /* Protected by the queue_lock */ 133 static request_queue_t *ubd_queue; 134 135 /* Protected by ubd_lock */ 136 static int fake_major = MAJOR_NR; 137 138 static struct gendisk *ubd_gendisk[MAX_DEV]; 139 static struct gendisk *fake_gendisk[MAX_DEV]; 140 141 #ifdef CONFIG_BLK_DEV_UBD_SYNC 142 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 143 .cl = 1 }) 144 #else 145 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 146 .cl = 1 }) 147 #endif 148 149 /* Not protected - changed only in ubd_setup_common and then only to 150 * to enable O_SYNC. 151 */ 152 static struct openflags global_openflags = OPEN_FLAGS; 153 154 struct cow { 155 /* This is the backing file, actually */ 156 char *file; 157 int fd; 158 unsigned long *bitmap; 159 unsigned long bitmap_len; 160 int bitmap_offset; 161 int data_offset; 162 }; 163 164 struct ubd { 165 char *file; 166 int count; 167 int fd; 168 __u64 size; 169 struct openflags boot_openflags; 170 struct openflags openflags; 171 int shared; 172 int no_cow; 173 struct cow cow; 174 struct platform_device pdev; 175 }; 176 177 #define DEFAULT_COW { \ 178 .file = NULL, \ 179 .fd = -1, \ 180 .bitmap = NULL, \ 181 .bitmap_offset = 0, \ 182 .data_offset = 0, \ 183 } 184 185 #define DEFAULT_UBD { \ 186 .file = NULL, \ 187 .count = 0, \ 188 .fd = -1, \ 189 .size = -1, \ 190 .boot_openflags = OPEN_FLAGS, \ 191 .openflags = OPEN_FLAGS, \ 192 .no_cow = 0, \ 193 .shared = 0, \ 194 .cow = DEFAULT_COW, \ 195 } 196 197 struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; 198 199 static int ubd0_init(void) 200 { 201 struct ubd *dev = &ubd_dev[0]; 202 203 if(dev->file == NULL) 204 dev->file = "root_fs"; 205 return(0); 206 } 207 208 __initcall(ubd0_init); 209 210 /* Only changed by fake_ide_setup which is a setup */ 211 static int fake_ide = 0; 212 static struct proc_dir_entry *proc_ide_root = NULL; 213 static struct proc_dir_entry *proc_ide = NULL; 214 215 static void make_proc_ide(void) 216 { 217 proc_ide_root = proc_mkdir("ide", NULL); 218 proc_ide = proc_mkdir("ide0", proc_ide_root); 219 } 220 221 static int proc_ide_read_media(char *page, char **start, off_t off, int count, 222 int *eof, void *data) 223 { 224 int len; 225 226 strcpy(page, "disk\n"); 227 len = strlen("disk\n"); 228 len -= off; 229 if (len < count){ 230 *eof = 1; 231 if (len <= 0) return 0; 232 } 233 else len = count; 234 *start = page + off; 235 return len; 236 } 237 238 static void make_ide_entries(char *dev_name) 239 { 240 struct proc_dir_entry *dir, *ent; 241 char name[64]; 242 243 if(proc_ide_root == NULL) make_proc_ide(); 244 245 dir = proc_mkdir(dev_name, proc_ide); 246 if(!dir) return; 247 248 ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir); 249 if(!ent) return; 250 ent->nlink = 1; 251 ent->data = NULL; 252 ent->read_proc = proc_ide_read_media; 253 ent->write_proc = NULL; 254 sprintf(name,"ide0/%s", dev_name); 255 proc_symlink(dev_name, proc_ide_root, name); 256 } 257 258 static int fake_ide_setup(char *str) 259 { 260 fake_ide = 1; 261 return(1); 262 } 263 264 __setup("fake_ide", fake_ide_setup); 265 266 __uml_help(fake_ide_setup, 267 "fake_ide\n" 268 " Create ide0 entries that map onto ubd devices.\n\n" 269 ); 270 271 static int parse_unit(char **ptr) 272 { 273 char *str = *ptr, *end; 274 int n = -1; 275 276 if(isdigit(*str)) { 277 n = simple_strtoul(str, &end, 0); 278 if(end == str) 279 return(-1); 280 *ptr = end; 281 } 282 else if (('a' <= *str) && (*str <= 'h')) { 283 n = *str - 'a'; 284 str++; 285 *ptr = str; 286 } 287 return(n); 288 } 289 290 static int ubd_setup_common(char *str, int *index_out) 291 { 292 struct ubd *dev; 293 struct openflags flags = global_openflags; 294 char *backing_file; 295 int n, err, i; 296 297 if(index_out) *index_out = -1; 298 n = *str; 299 if(n == '='){ 300 char *end; 301 int major; 302 303 str++; 304 if(!strcmp(str, "sync")){ 305 global_openflags = of_sync(global_openflags); 306 return(0); 307 } 308 major = simple_strtoul(str, &end, 0); 309 if((*end != '\0') || (end == str)){ 310 printk(KERN_ERR 311 "ubd_setup : didn't parse major number\n"); 312 return(1); 313 } 314 315 err = 1; 316 spin_lock(&ubd_lock); 317 if(fake_major != MAJOR_NR){ 318 printk(KERN_ERR "Can't assign a fake major twice\n"); 319 goto out1; 320 } 321 322 fake_major = major; 323 324 printk(KERN_INFO "Setting extra ubd major number to %d\n", 325 major); 326 err = 0; 327 out1: 328 spin_unlock(&ubd_lock); 329 return(err); 330 } 331 332 n = parse_unit(&str); 333 if(n < 0){ 334 printk(KERN_ERR "ubd_setup : couldn't parse unit number " 335 "'%s'\n", str); 336 return(1); 337 } 338 if(n >= MAX_DEV){ 339 printk(KERN_ERR "ubd_setup : index %d out of range " 340 "(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1); 341 return(1); 342 } 343 344 err = 1; 345 spin_lock(&ubd_lock); 346 347 dev = &ubd_dev[n]; 348 if(dev->file != NULL){ 349 printk(KERN_ERR "ubd_setup : device already configured\n"); 350 goto out; 351 } 352 353 if (index_out) 354 *index_out = n; 355 356 for (i = 0; i < sizeof("rscd="); i++) { 357 switch (*str) { 358 case 'r': 359 flags.w = 0; 360 break; 361 case 's': 362 flags.s = 1; 363 break; 364 case 'd': 365 dev->no_cow = 1; 366 break; 367 case 'c': 368 dev->shared = 1; 369 break; 370 case '=': 371 str++; 372 goto break_loop; 373 default: 374 printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r, s, c, or d)\n"); 375 goto out; 376 } 377 str++; 378 } 379 380 if (*str == '=') 381 printk(KERN_ERR "ubd_setup : Too many flags specified\n"); 382 else 383 printk(KERN_ERR "ubd_setup : Expected '='\n"); 384 goto out; 385 386 break_loop: 387 err = 0; 388 backing_file = strchr(str, ','); 389 390 if (!backing_file) { 391 backing_file = strchr(str, ':'); 392 } 393 394 if(backing_file){ 395 if(dev->no_cow) 396 printk(KERN_ERR "Can't specify both 'd' and a " 397 "cow file\n"); 398 else { 399 *backing_file = '\0'; 400 backing_file++; 401 } 402 } 403 dev->file = str; 404 dev->cow.file = backing_file; 405 dev->boot_openflags = flags; 406 out: 407 spin_unlock(&ubd_lock); 408 return(err); 409 } 410 411 static int ubd_setup(char *str) 412 { 413 ubd_setup_common(str, NULL); 414 return(1); 415 } 416 417 __setup("ubd", ubd_setup); 418 __uml_help(ubd_setup, 419 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" 420 " This is used to associate a device with a file in the underlying\n" 421 " filesystem. When specifying two filenames, the first one is the\n" 422 " COW name and the second is the backing file name. As separator you can\n" 423 " use either a ':' or a ',': the first one allows writing things like;\n" 424 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 425 " while with a ',' the shell would not expand the 2nd '~'.\n" 426 " When using only one filename, UML will detect whether to thread it like\n" 427 " a COW file or a backing file. To override this detection, add the 'd'\n" 428 " flag:\n" 429 " ubd0d=BackingFile\n" 430 " Usually, there is a filesystem in the file, but \n" 431 " that's not required. Swap devices containing swap files can be\n" 432 " specified like this. Also, a file which doesn't contain a\n" 433 " filesystem can have its contents read in the virtual \n" 434 " machine by running 'dd' on the device. <n> must be in the range\n" 435 " 0 to 7. Appending an 'r' to the number will cause that device\n" 436 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 437 " an 's' will cause data to be written to disk on the host immediately.\n\n" 438 ); 439 440 static int udb_setup(char *str) 441 { 442 printk("udb%s specified on command line is almost certainly a ubd -> " 443 "udb TYPO\n", str); 444 return(1); 445 } 446 447 __setup("udb", udb_setup); 448 __uml_help(udb_setup, 449 "udb\n" 450 " This option is here solely to catch ubd -> udb typos, which can be\n" 451 " to impossible to catch visually unless you specifically look for\n" 452 " them. The only result of any option starting with 'udb' is an error\n" 453 " in the boot output.\n\n" 454 ); 455 456 static int fakehd_set = 0; 457 static int fakehd(char *str) 458 { 459 printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n"); 460 fakehd_set = 1; 461 return 1; 462 } 463 464 __setup("fakehd", fakehd); 465 __uml_help(fakehd, 466 "fakehd\n" 467 " Change the ubd device name to \"hd\".\n\n" 468 ); 469 470 static void do_ubd_request(request_queue_t * q); 471 472 /* Only changed by ubd_init, which is an initcall. */ 473 int thread_fd = -1; 474 475 /* Changed by ubd_handler, which is serialized because interrupts only 476 * happen on CPU 0. 477 */ 478 int intr_count = 0; 479 480 /* call ubd_finish if you need to serialize */ 481 static void __ubd_finish(struct request *req, int error) 482 { 483 int nsect; 484 485 if(error){ 486 end_request(req, 0); 487 return; 488 } 489 nsect = req->current_nr_sectors; 490 req->sector += nsect; 491 req->buffer += nsect << 9; 492 req->errors = 0; 493 req->nr_sectors -= nsect; 494 req->current_nr_sectors = 0; 495 end_request(req, 1); 496 } 497 498 static inline void ubd_finish(struct request *req, int error) 499 { 500 spin_lock(&ubd_io_lock); 501 __ubd_finish(req, error); 502 spin_unlock(&ubd_io_lock); 503 } 504 505 /* Called without ubd_io_lock held */ 506 static void ubd_handler(void) 507 { 508 struct io_thread_req req; 509 struct request *rq = elv_next_request(ubd_queue); 510 int n; 511 512 do_ubd = NULL; 513 intr_count++; 514 n = os_read_file(thread_fd, &req, sizeof(req)); 515 if(n != sizeof(req)){ 516 printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, " 517 "err = %d\n", os_getpid(), -n); 518 spin_lock(&ubd_io_lock); 519 end_request(rq, 0); 520 spin_unlock(&ubd_io_lock); 521 return; 522 } 523 524 ubd_finish(rq, req.error); 525 reactivate_fd(thread_fd, UBD_IRQ); 526 do_ubd_request(ubd_queue); 527 } 528 529 static irqreturn_t ubd_intr(int irq, void *dev, struct pt_regs *unused) 530 { 531 ubd_handler(); 532 return(IRQ_HANDLED); 533 } 534 535 /* Only changed by ubd_init, which is an initcall. */ 536 static int io_pid = -1; 537 538 void kill_io_thread(void) 539 { 540 if(io_pid != -1) 541 os_kill_process(io_pid, 1); 542 } 543 544 __uml_exitcall(kill_io_thread); 545 546 static int ubd_file_size(struct ubd *dev, __u64 *size_out) 547 { 548 char *file; 549 550 file = dev->cow.file ? dev->cow.file : dev->file; 551 return(os_file_size(file, size_out)); 552 } 553 554 static void ubd_close(struct ubd *dev) 555 { 556 os_close_file(dev->fd); 557 if(dev->cow.file == NULL) 558 return; 559 560 os_close_file(dev->cow.fd); 561 vfree(dev->cow.bitmap); 562 dev->cow.bitmap = NULL; 563 } 564 565 static int ubd_open_dev(struct ubd *dev) 566 { 567 struct openflags flags; 568 char **back_ptr; 569 int err, create_cow, *create_ptr; 570 571 dev->openflags = dev->boot_openflags; 572 create_cow = 0; 573 create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL; 574 back_ptr = dev->no_cow ? NULL : &dev->cow.file; 575 dev->fd = open_ubd_file(dev->file, &dev->openflags, dev->shared, 576 back_ptr, &dev->cow.bitmap_offset, 577 &dev->cow.bitmap_len, &dev->cow.data_offset, 578 create_ptr); 579 580 if((dev->fd == -ENOENT) && create_cow){ 581 dev->fd = create_cow_file(dev->file, dev->cow.file, 582 dev->openflags, 1 << 9, PAGE_SIZE, 583 &dev->cow.bitmap_offset, 584 &dev->cow.bitmap_len, 585 &dev->cow.data_offset); 586 if(dev->fd >= 0){ 587 printk(KERN_INFO "Creating \"%s\" as COW file for " 588 "\"%s\"\n", dev->file, dev->cow.file); 589 } 590 } 591 592 if(dev->fd < 0){ 593 printk("Failed to open '%s', errno = %d\n", dev->file, 594 -dev->fd); 595 return(dev->fd); 596 } 597 598 if(dev->cow.file != NULL){ 599 err = -ENOMEM; 600 dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len); 601 if(dev->cow.bitmap == NULL){ 602 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 603 goto error; 604 } 605 flush_tlb_kernel_vm(); 606 607 err = read_cow_bitmap(dev->fd, dev->cow.bitmap, 608 dev->cow.bitmap_offset, 609 dev->cow.bitmap_len); 610 if(err < 0) 611 goto error; 612 613 flags = dev->openflags; 614 flags.w = 0; 615 err = open_ubd_file(dev->cow.file, &flags, dev->shared, NULL, 616 NULL, NULL, NULL, NULL); 617 if(err < 0) goto error; 618 dev->cow.fd = err; 619 } 620 return(0); 621 error: 622 os_close_file(dev->fd); 623 return(err); 624 } 625 626 static int ubd_new_disk(int major, u64 size, int unit, 627 struct gendisk **disk_out) 628 629 { 630 struct gendisk *disk; 631 char from[sizeof("ubd/nnnnn\0")], to[sizeof("discnnnnn/disc\0")]; 632 int err; 633 634 disk = alloc_disk(1 << UBD_SHIFT); 635 if(disk == NULL) 636 return(-ENOMEM); 637 638 disk->major = major; 639 disk->first_minor = unit << UBD_SHIFT; 640 disk->fops = &ubd_blops; 641 set_capacity(disk, size / 512); 642 if(major == MAJOR_NR){ 643 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 644 sprintf(disk->devfs_name, "ubd/disc%d", unit); 645 sprintf(from, "ubd/%d", unit); 646 sprintf(to, "disc%d/disc", unit); 647 err = devfs_mk_symlink(from, to); 648 if(err) 649 printk("ubd_new_disk failed to make link from %s to " 650 "%s, error = %d\n", from, to, err); 651 } 652 else { 653 sprintf(disk->disk_name, "ubd_fake%d", unit); 654 sprintf(disk->devfs_name, "ubd_fake/disc%d", unit); 655 } 656 657 /* sysfs register (not for ide fake devices) */ 658 if (major == MAJOR_NR) { 659 ubd_dev[unit].pdev.id = unit; 660 ubd_dev[unit].pdev.name = DRIVER_NAME; 661 platform_device_register(&ubd_dev[unit].pdev); 662 disk->driverfs_dev = &ubd_dev[unit].pdev.dev; 663 } 664 665 disk->private_data = &ubd_dev[unit]; 666 disk->queue = ubd_queue; 667 add_disk(disk); 668 669 *disk_out = disk; 670 return 0; 671 } 672 673 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9)) 674 675 static int ubd_add(int n) 676 { 677 struct ubd *dev = &ubd_dev[n]; 678 int err; 679 680 err = -ENODEV; 681 if(dev->file == NULL) 682 goto out; 683 684 if (ubd_open_dev(dev)) 685 goto out; 686 687 err = ubd_file_size(dev, &dev->size); 688 if(err < 0) 689 goto out_close; 690 691 dev->size = ROUND_BLOCK(dev->size); 692 693 err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]); 694 if(err) 695 goto out_close; 696 697 if(fake_major != MAJOR_NR) 698 ubd_new_disk(fake_major, dev->size, n, 699 &fake_gendisk[n]); 700 701 /* perhaps this should also be under the "if (fake_major)" above */ 702 /* using the fake_disk->disk_name and also the fakehd_set name */ 703 if (fake_ide) 704 make_ide_entries(ubd_gendisk[n]->disk_name); 705 706 err = 0; 707 out_close: 708 ubd_close(dev); 709 out: 710 return err; 711 } 712 713 static int ubd_config(char *str) 714 { 715 int n, err; 716 717 str = kstrdup(str, GFP_KERNEL); 718 if(str == NULL){ 719 printk(KERN_ERR "ubd_config failed to strdup string\n"); 720 return(1); 721 } 722 err = ubd_setup_common(str, &n); 723 if(err){ 724 kfree(str); 725 return(-1); 726 } 727 if(n == -1) return(0); 728 729 spin_lock(&ubd_lock); 730 err = ubd_add(n); 731 if(err) 732 ubd_dev[n].file = NULL; 733 spin_unlock(&ubd_lock); 734 735 return(err); 736 } 737 738 static int ubd_get_config(char *name, char *str, int size, char **error_out) 739 { 740 struct ubd *dev; 741 int n, len = 0; 742 743 n = parse_unit(&name); 744 if((n >= MAX_DEV) || (n < 0)){ 745 *error_out = "ubd_get_config : device number out of range"; 746 return(-1); 747 } 748 749 dev = &ubd_dev[n]; 750 spin_lock(&ubd_lock); 751 752 if(dev->file == NULL){ 753 CONFIG_CHUNK(str, size, len, "", 1); 754 goto out; 755 } 756 757 CONFIG_CHUNK(str, size, len, dev->file, 0); 758 759 if(dev->cow.file != NULL){ 760 CONFIG_CHUNK(str, size, len, ",", 0); 761 CONFIG_CHUNK(str, size, len, dev->cow.file, 1); 762 } 763 else CONFIG_CHUNK(str, size, len, "", 1); 764 765 out: 766 spin_unlock(&ubd_lock); 767 return(len); 768 } 769 770 static int ubd_id(char **str, int *start_out, int *end_out) 771 { 772 int n; 773 774 n = parse_unit(str); 775 *start_out = 0; 776 *end_out = MAX_DEV - 1; 777 return n; 778 } 779 780 static int ubd_remove(int n) 781 { 782 struct ubd *dev; 783 int err = -ENODEV; 784 785 spin_lock(&ubd_lock); 786 787 if(ubd_gendisk[n] == NULL) 788 goto out; 789 790 dev = &ubd_dev[n]; 791 792 if(dev->file == NULL) 793 goto out; 794 795 /* you cannot remove a open disk */ 796 err = -EBUSY; 797 if(dev->count > 0) 798 goto out; 799 800 del_gendisk(ubd_gendisk[n]); 801 put_disk(ubd_gendisk[n]); 802 ubd_gendisk[n] = NULL; 803 804 if(fake_gendisk[n] != NULL){ 805 del_gendisk(fake_gendisk[n]); 806 put_disk(fake_gendisk[n]); 807 fake_gendisk[n] = NULL; 808 } 809 810 platform_device_unregister(&dev->pdev); 811 *dev = ((struct ubd) DEFAULT_UBD); 812 err = 0; 813 out: 814 spin_unlock(&ubd_lock); 815 return err; 816 } 817 818 static struct mc_device ubd_mc = { 819 .name = "ubd", 820 .config = ubd_config, 821 .get_config = ubd_get_config, 822 .id = ubd_id, 823 .remove = ubd_remove, 824 }; 825 826 static int ubd_mc_init(void) 827 { 828 mconsole_register_dev(&ubd_mc); 829 return 0; 830 } 831 832 __initcall(ubd_mc_init); 833 834 static struct platform_driver ubd_driver = { 835 .driver = { 836 .name = DRIVER_NAME, 837 }, 838 }; 839 840 int ubd_init(void) 841 { 842 int i; 843 844 devfs_mk_dir("ubd"); 845 if (register_blkdev(MAJOR_NR, "ubd")) 846 return -1; 847 848 ubd_queue = blk_init_queue(do_ubd_request, &ubd_io_lock); 849 if (!ubd_queue) { 850 unregister_blkdev(MAJOR_NR, "ubd"); 851 return -1; 852 } 853 854 if (fake_major != MAJOR_NR) { 855 char name[sizeof("ubd_nnn\0")]; 856 857 snprintf(name, sizeof(name), "ubd_%d", fake_major); 858 devfs_mk_dir(name); 859 if (register_blkdev(fake_major, "ubd")) 860 return -1; 861 } 862 platform_driver_register(&ubd_driver); 863 for (i = 0; i < MAX_DEV; i++) 864 ubd_add(i); 865 return 0; 866 } 867 868 late_initcall(ubd_init); 869 870 int ubd_driver_init(void){ 871 unsigned long stack; 872 int err; 873 874 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 875 if(global_openflags.s){ 876 printk(KERN_INFO "ubd: Synchronous mode\n"); 877 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 878 * enough. So use anyway the io thread. */ 879 } 880 stack = alloc_stack(0, 0); 881 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), 882 &thread_fd); 883 if(io_pid < 0){ 884 printk(KERN_ERR 885 "ubd : Failed to start I/O thread (errno = %d) - " 886 "falling back to synchronous I/O\n", -io_pid); 887 io_pid = -1; 888 return(0); 889 } 890 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 891 SA_INTERRUPT, "ubd", ubd_dev); 892 if(err != 0) 893 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 894 return 0; 895 } 896 897 device_initcall(ubd_driver_init); 898 899 static int ubd_open(struct inode *inode, struct file *filp) 900 { 901 struct gendisk *disk = inode->i_bdev->bd_disk; 902 struct ubd *dev = disk->private_data; 903 int err = 0; 904 905 if(dev->count == 0){ 906 err = ubd_open_dev(dev); 907 if(err){ 908 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 909 disk->disk_name, dev->file, -err); 910 goto out; 911 } 912 } 913 dev->count++; 914 set_disk_ro(disk, !dev->openflags.w); 915 916 /* This should no more be needed. And it didn't work anyway to exclude 917 * read-write remounting of filesystems.*/ 918 /*if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){ 919 if(--dev->count == 0) ubd_close(dev); 920 err = -EROFS; 921 }*/ 922 out: 923 return(err); 924 } 925 926 static int ubd_release(struct inode * inode, struct file * file) 927 { 928 struct gendisk *disk = inode->i_bdev->bd_disk; 929 struct ubd *dev = disk->private_data; 930 931 if(--dev->count == 0) 932 ubd_close(dev); 933 return(0); 934 } 935 936 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 937 __u64 *cow_offset, unsigned long *bitmap, 938 __u64 bitmap_offset, unsigned long *bitmap_words, 939 __u64 bitmap_len) 940 { 941 __u64 sector = io_offset >> 9; 942 int i, update_bitmap = 0; 943 944 for(i = 0; i < length >> 9; i++){ 945 if(cow_mask != NULL) 946 ubd_set_bit(i, (unsigned char *) cow_mask); 947 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 948 continue; 949 950 update_bitmap = 1; 951 ubd_set_bit(sector + i, (unsigned char *) bitmap); 952 } 953 954 if(!update_bitmap) 955 return; 956 957 *cow_offset = sector / (sizeof(unsigned long) * 8); 958 959 /* This takes care of the case where we're exactly at the end of the 960 * device, and *cow_offset + 1 is off the end. So, just back it up 961 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 962 * for the original diagnosis. 963 */ 964 if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) / 965 sizeof(unsigned long) - 1)) 966 (*cow_offset)--; 967 968 bitmap_words[0] = bitmap[*cow_offset]; 969 bitmap_words[1] = bitmap[*cow_offset + 1]; 970 971 *cow_offset *= sizeof(unsigned long); 972 *cow_offset += bitmap_offset; 973 } 974 975 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, 976 __u64 bitmap_offset, __u64 bitmap_len) 977 { 978 __u64 sector = req->offset >> 9; 979 int i; 980 981 if(req->length > (sizeof(req->sector_mask) * 8) << 9) 982 panic("Operation too long"); 983 984 if(req->op == UBD_READ) { 985 for(i = 0; i < req->length >> 9; i++){ 986 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 987 ubd_set_bit(i, (unsigned char *) 988 &req->sector_mask); 989 } 990 } 991 else cowify_bitmap(req->offset, req->length, &req->sector_mask, 992 &req->cow_offset, bitmap, bitmap_offset, 993 req->bitmap_words, bitmap_len); 994 } 995 996 /* Called with ubd_io_lock held */ 997 static int prepare_request(struct request *req, struct io_thread_req *io_req) 998 { 999 struct gendisk *disk = req->rq_disk; 1000 struct ubd *dev = disk->private_data; 1001 __u64 offset; 1002 int len; 1003 1004 if(req->rq_status == RQ_INACTIVE) return(1); 1005 1006 /* This should be impossible now */ 1007 if((rq_data_dir(req) == WRITE) && !dev->openflags.w){ 1008 printk("Write attempted on readonly ubd device %s\n", 1009 disk->disk_name); 1010 end_request(req, 0); 1011 return(1); 1012 } 1013 1014 offset = ((__u64) req->sector) << 9; 1015 len = req->current_nr_sectors << 9; 1016 1017 io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd; 1018 io_req->fds[1] = dev->fd; 1019 io_req->cow_offset = -1; 1020 io_req->offset = offset; 1021 io_req->length = len; 1022 io_req->error = 0; 1023 io_req->sector_mask = 0; 1024 1025 io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; 1026 io_req->offsets[0] = 0; 1027 io_req->offsets[1] = dev->cow.data_offset; 1028 io_req->buffer = req->buffer; 1029 io_req->sectorsize = 1 << 9; 1030 1031 if(dev->cow.file != NULL) 1032 cowify_req(io_req, dev->cow.bitmap, dev->cow.bitmap_offset, 1033 dev->cow.bitmap_len); 1034 1035 return(0); 1036 } 1037 1038 /* Called with ubd_io_lock held */ 1039 static void do_ubd_request(request_queue_t *q) 1040 { 1041 struct io_thread_req io_req; 1042 struct request *req; 1043 int err, n; 1044 1045 if(thread_fd == -1){ 1046 while((req = elv_next_request(q)) != NULL){ 1047 err = prepare_request(req, &io_req); 1048 if(!err){ 1049 do_io(&io_req); 1050 __ubd_finish(req, io_req.error); 1051 } 1052 } 1053 } 1054 else { 1055 if(do_ubd || (req = elv_next_request(q)) == NULL) 1056 return; 1057 err = prepare_request(req, &io_req); 1058 if(!err){ 1059 do_ubd = ubd_handler; 1060 n = os_write_file(thread_fd, (char *) &io_req, 1061 sizeof(io_req)); 1062 if(n != sizeof(io_req)) 1063 printk("write to io thread failed, " 1064 "errno = %d\n", -n); 1065 } 1066 } 1067 } 1068 1069 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) 1070 { 1071 struct ubd *dev = bdev->bd_disk->private_data; 1072 1073 geo->heads = 128; 1074 geo->sectors = 32; 1075 geo->cylinders = dev->size / (128 * 32 * 512); 1076 return 0; 1077 } 1078 1079 static int ubd_ioctl(struct inode * inode, struct file * file, 1080 unsigned int cmd, unsigned long arg) 1081 { 1082 struct ubd *dev = inode->i_bdev->bd_disk->private_data; 1083 struct hd_driveid ubd_id = { 1084 .cyls = 0, 1085 .heads = 128, 1086 .sectors = 32, 1087 }; 1088 1089 switch (cmd) { 1090 struct cdrom_volctrl volume; 1091 case HDIO_GET_IDENTITY: 1092 ubd_id.cyls = dev->size / (128 * 32 * 512); 1093 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1094 sizeof(ubd_id))) 1095 return(-EFAULT); 1096 return(0); 1097 1098 case CDROMVOLREAD: 1099 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1100 return(-EFAULT); 1101 volume.channel0 = 255; 1102 volume.channel1 = 255; 1103 volume.channel2 = 255; 1104 volume.channel3 = 255; 1105 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1106 return(-EFAULT); 1107 return(0); 1108 } 1109 return(-EINVAL); 1110 } 1111 1112 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) 1113 { 1114 struct uml_stat buf1, buf2; 1115 int err; 1116 1117 if(from_cmdline == NULL) 1118 return 0; 1119 if(!strcmp(from_cmdline, from_cow)) 1120 return 0; 1121 1122 err = os_stat_file(from_cmdline, &buf1); 1123 if(err < 0){ 1124 printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err); 1125 return 0; 1126 } 1127 err = os_stat_file(from_cow, &buf2); 1128 if(err < 0){ 1129 printk("Couldn't stat '%s', err = %d\n", from_cow, -err); 1130 return 1; 1131 } 1132 if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 1133 return 0; 1134 1135 printk("Backing file mismatch - \"%s\" requested,\n" 1136 "\"%s\" specified in COW header of \"%s\"\n", 1137 from_cmdline, from_cow, cow); 1138 return 1; 1139 } 1140 1141 static int backing_file_mismatch(char *file, __u64 size, time_t mtime) 1142 { 1143 unsigned long modtime; 1144 unsigned long long actual; 1145 int err; 1146 1147 err = os_file_modtime(file, &modtime); 1148 if(err < 0){ 1149 printk("Failed to get modification time of backing file " 1150 "\"%s\", err = %d\n", file, -err); 1151 return(err); 1152 } 1153 1154 err = os_file_size(file, &actual); 1155 if(err < 0){ 1156 printk("Failed to get size of backing file \"%s\", " 1157 "err = %d\n", file, -err); 1158 return(err); 1159 } 1160 1161 if(actual != size){ 1162 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 1163 * the typecast.*/ 1164 printk("Size mismatch (%llu vs %llu) of COW header vs backing " 1165 "file\n", (unsigned long long) size, actual); 1166 return(-EINVAL); 1167 } 1168 if(modtime != mtime){ 1169 printk("mtime mismatch (%ld vs %ld) of COW header vs backing " 1170 "file\n", mtime, modtime); 1171 return(-EINVAL); 1172 } 1173 return(0); 1174 } 1175 1176 int read_cow_bitmap(int fd, void *buf, int offset, int len) 1177 { 1178 int err; 1179 1180 err = os_seek_file(fd, offset); 1181 if(err < 0) 1182 return(err); 1183 1184 err = os_read_file(fd, buf, len); 1185 if(err < 0) 1186 return(err); 1187 1188 return(0); 1189 } 1190 1191 int open_ubd_file(char *file, struct openflags *openflags, int shared, 1192 char **backing_file_out, int *bitmap_offset_out, 1193 unsigned long *bitmap_len_out, int *data_offset_out, 1194 int *create_cow_out) 1195 { 1196 time_t mtime; 1197 unsigned long long size; 1198 __u32 version, align; 1199 char *backing_file; 1200 int fd, err, sectorsize, asked_switch, mode = 0644; 1201 1202 fd = os_open_file(file, *openflags, mode); 1203 if (fd < 0) { 1204 if ((fd == -ENOENT) && (create_cow_out != NULL)) 1205 *create_cow_out = 1; 1206 if (!openflags->w || 1207 ((fd != -EROFS) && (fd != -EACCES))) 1208 return fd; 1209 openflags->w = 0; 1210 fd = os_open_file(file, *openflags, mode); 1211 if (fd < 0) 1212 return fd; 1213 } 1214 1215 if(shared) 1216 printk("Not locking \"%s\" on the host\n", file); 1217 else { 1218 err = os_lock_file(fd, openflags->w); 1219 if(err < 0){ 1220 printk("Failed to lock '%s', err = %d\n", file, -err); 1221 goto out_close; 1222 } 1223 } 1224 1225 /* Succesful return case! */ 1226 if(backing_file_out == NULL) 1227 return(fd); 1228 1229 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 1230 &size, §orsize, &align, bitmap_offset_out); 1231 if(err && (*backing_file_out != NULL)){ 1232 printk("Failed to read COW header from COW file \"%s\", " 1233 "errno = %d\n", file, -err); 1234 goto out_close; 1235 } 1236 if(err) 1237 return(fd); 1238 1239 asked_switch = path_requires_switch(*backing_file_out, backing_file, file); 1240 1241 /* Allow switching only if no mismatch. */ 1242 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, mtime)) { 1243 printk("Switching backing file to '%s'\n", *backing_file_out); 1244 err = write_cow_header(file, fd, *backing_file_out, 1245 sectorsize, align, &size); 1246 if (err) { 1247 printk("Switch failed, errno = %d\n", -err); 1248 goto out_close; 1249 } 1250 } else { 1251 *backing_file_out = backing_file; 1252 err = backing_file_mismatch(*backing_file_out, size, mtime); 1253 if (err) 1254 goto out_close; 1255 } 1256 1257 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 1258 bitmap_len_out, data_offset_out); 1259 1260 return fd; 1261 out_close: 1262 os_close_file(fd); 1263 return err; 1264 } 1265 1266 int create_cow_file(char *cow_file, char *backing_file, struct openflags flags, 1267 int sectorsize, int alignment, int *bitmap_offset_out, 1268 unsigned long *bitmap_len_out, int *data_offset_out) 1269 { 1270 int err, fd; 1271 1272 flags.c = 1; 1273 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); 1274 if(fd < 0){ 1275 err = fd; 1276 printk("Open of COW file '%s' failed, errno = %d\n", cow_file, 1277 -err); 1278 goto out; 1279 } 1280 1281 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 1282 bitmap_offset_out, bitmap_len_out, 1283 data_offset_out); 1284 if(!err) 1285 return(fd); 1286 os_close_file(fd); 1287 out: 1288 return(err); 1289 } 1290 1291 static int update_bitmap(struct io_thread_req *req) 1292 { 1293 int n; 1294 1295 if(req->cow_offset == -1) 1296 return(0); 1297 1298 n = os_seek_file(req->fds[1], req->cow_offset); 1299 if(n < 0){ 1300 printk("do_io - bitmap lseek failed : err = %d\n", -n); 1301 return(1); 1302 } 1303 1304 n = os_write_file(req->fds[1], &req->bitmap_words, 1305 sizeof(req->bitmap_words)); 1306 if(n != sizeof(req->bitmap_words)){ 1307 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, 1308 req->fds[1]); 1309 return(1); 1310 } 1311 1312 return(0); 1313 } 1314 1315 void do_io(struct io_thread_req *req) 1316 { 1317 char *buf; 1318 unsigned long len; 1319 int n, nsectors, start, end, bit; 1320 int err; 1321 __u64 off; 1322 1323 nsectors = req->length / req->sectorsize; 1324 start = 0; 1325 do { 1326 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); 1327 end = start; 1328 while((end < nsectors) && 1329 (ubd_test_bit(end, (unsigned char *) 1330 &req->sector_mask) == bit)) 1331 end++; 1332 1333 off = req->offset + req->offsets[bit] + 1334 start * req->sectorsize; 1335 len = (end - start) * req->sectorsize; 1336 buf = &req->buffer[start * req->sectorsize]; 1337 1338 err = os_seek_file(req->fds[bit], off); 1339 if(err < 0){ 1340 printk("do_io - lseek failed : err = %d\n", -err); 1341 req->error = 1; 1342 return; 1343 } 1344 if(req->op == UBD_READ){ 1345 n = 0; 1346 do { 1347 buf = &buf[n]; 1348 len -= n; 1349 n = os_read_file(req->fds[bit], buf, len); 1350 if (n < 0) { 1351 printk("do_io - read failed, err = %d " 1352 "fd = %d\n", -n, req->fds[bit]); 1353 req->error = 1; 1354 return; 1355 } 1356 } while((n < len) && (n != 0)); 1357 if (n < len) memset(&buf[n], 0, len - n); 1358 } else { 1359 n = os_write_file(req->fds[bit], buf, len); 1360 if(n != len){ 1361 printk("do_io - write failed err = %d " 1362 "fd = %d\n", -n, req->fds[bit]); 1363 req->error = 1; 1364 return; 1365 } 1366 } 1367 1368 start = end; 1369 } while(start < nsectors); 1370 1371 req->error = update_bitmap(req); 1372 } 1373 1374 /* Changed in start_io_thread, which is serialized by being called only 1375 * from ubd_init, which is an initcall. 1376 */ 1377 int kernel_fd = -1; 1378 1379 /* Only changed by the io thread */ 1380 int io_count = 0; 1381 1382 int io_thread(void *arg) 1383 { 1384 struct io_thread_req req; 1385 int n; 1386 1387 ignore_sigwinch_sig(); 1388 while(1){ 1389 n = os_read_file(kernel_fd, &req, sizeof(req)); 1390 if(n != sizeof(req)){ 1391 if(n < 0) 1392 printk("io_thread - read failed, fd = %d, " 1393 "err = %d\n", kernel_fd, -n); 1394 else { 1395 printk("io_thread - short read, fd = %d, " 1396 "length = %d\n", kernel_fd, n); 1397 } 1398 continue; 1399 } 1400 io_count++; 1401 do_io(&req); 1402 n = os_write_file(kernel_fd, &req, sizeof(req)); 1403 if(n != sizeof(req)) 1404 printk("io_thread - write failed, fd = %d, err = %d\n", 1405 kernel_fd, -n); 1406 } 1407 1408 return 0; 1409 } 1410