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 "asm/segment.h" 39 #include "asm/uaccess.h" 40 #include "asm/irq.h" 41 #include "asm/types.h" 42 #include "asm/tlbflush.h" 43 #include "user_util.h" 44 #include "mem_user.h" 45 #include "kern_util.h" 46 #include "kern.h" 47 #include "mconsole_kern.h" 48 #include "init.h" 49 #include "irq_user.h" 50 #include "irq_kern.h" 51 #include "ubd_user.h" 52 #include "2_5compat.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, UBD_MMAP }; 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 map_fd; 72 unsigned long long map_offset; 73 int error; 74 }; 75 76 extern int open_ubd_file(char *file, struct openflags *openflags, 77 char **backing_file_out, int *bitmap_offset_out, 78 unsigned long *bitmap_len_out, int *data_offset_out, 79 int *create_cow_out); 80 extern int create_cow_file(char *cow_file, char *backing_file, 81 struct openflags flags, int sectorsize, 82 int alignment, int *bitmap_offset_out, 83 unsigned long *bitmap_len_out, 84 int *data_offset_out); 85 extern int read_cow_bitmap(int fd, void *buf, int offset, int len); 86 extern void do_io(struct io_thread_req *req); 87 88 static inline int ubd_test_bit(__u64 bit, unsigned char *data) 89 { 90 __u64 n; 91 int bits, off; 92 93 bits = sizeof(data[0]) * 8; 94 n = bit / bits; 95 off = bit % bits; 96 return((data[n] & (1 << off)) != 0); 97 } 98 99 static inline void ubd_set_bit(__u64 bit, unsigned char *data) 100 { 101 __u64 n; 102 int bits, off; 103 104 bits = sizeof(data[0]) * 8; 105 n = bit / bits; 106 off = bit % bits; 107 data[n] |= (1 << off); 108 } 109 /*End stuff from ubd_user.h*/ 110 111 #define DRIVER_NAME "uml-blkdev" 112 113 static DEFINE_SPINLOCK(ubd_io_lock); 114 static DEFINE_SPINLOCK(ubd_lock); 115 116 static void (*do_ubd)(void); 117 118 static int ubd_open(struct inode * inode, struct file * filp); 119 static int ubd_release(struct inode * inode, struct file * file); 120 static int ubd_ioctl(struct inode * inode, struct file * file, 121 unsigned int cmd, unsigned long arg); 122 123 #define MAX_DEV (8) 124 125 /* Changed in early boot */ 126 static int ubd_do_mmap = 0; 127 #define UBD_MMAP_BLOCK_SIZE PAGE_SIZE 128 129 static struct block_device_operations ubd_blops = { 130 .owner = THIS_MODULE, 131 .open = ubd_open, 132 .release = ubd_release, 133 .ioctl = ubd_ioctl, 134 }; 135 136 /* Protected by the queue_lock */ 137 static request_queue_t *ubd_queue; 138 139 /* Protected by ubd_lock */ 140 static int fake_major = MAJOR_NR; 141 142 static struct gendisk *ubd_gendisk[MAX_DEV]; 143 static struct gendisk *fake_gendisk[MAX_DEV]; 144 145 #ifdef CONFIG_BLK_DEV_UBD_SYNC 146 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 147 .cl = 1 }) 148 #else 149 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 150 .cl = 1 }) 151 #endif 152 153 /* Not protected - changed only in ubd_setup_common and then only to 154 * to enable O_SYNC. 155 */ 156 static struct openflags global_openflags = OPEN_FLAGS; 157 158 struct cow { 159 char *file; 160 int fd; 161 unsigned long *bitmap; 162 unsigned long bitmap_len; 163 int bitmap_offset; 164 int data_offset; 165 }; 166 167 struct ubd { 168 char *file; 169 int count; 170 int fd; 171 __u64 size; 172 struct openflags boot_openflags; 173 struct openflags openflags; 174 int no_cow; 175 struct cow cow; 176 struct platform_device pdev; 177 178 int map_writes; 179 int map_reads; 180 int nomap_writes; 181 int nomap_reads; 182 int write_maps; 183 }; 184 185 #define DEFAULT_COW { \ 186 .file = NULL, \ 187 .fd = -1, \ 188 .bitmap = NULL, \ 189 .bitmap_offset = 0, \ 190 .data_offset = 0, \ 191 } 192 193 #define DEFAULT_UBD { \ 194 .file = NULL, \ 195 .count = 0, \ 196 .fd = -1, \ 197 .size = -1, \ 198 .boot_openflags = OPEN_FLAGS, \ 199 .openflags = OPEN_FLAGS, \ 200 .no_cow = 0, \ 201 .cow = DEFAULT_COW, \ 202 .map_writes = 0, \ 203 .map_reads = 0, \ 204 .nomap_writes = 0, \ 205 .nomap_reads = 0, \ 206 .write_maps = 0, \ 207 } 208 209 struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; 210 211 static int ubd0_init(void) 212 { 213 struct ubd *dev = &ubd_dev[0]; 214 215 if(dev->file == NULL) 216 dev->file = "root_fs"; 217 return(0); 218 } 219 220 __initcall(ubd0_init); 221 222 /* Only changed by fake_ide_setup which is a setup */ 223 static int fake_ide = 0; 224 static struct proc_dir_entry *proc_ide_root = NULL; 225 static struct proc_dir_entry *proc_ide = NULL; 226 227 static void make_proc_ide(void) 228 { 229 proc_ide_root = proc_mkdir("ide", NULL); 230 proc_ide = proc_mkdir("ide0", proc_ide_root); 231 } 232 233 static int proc_ide_read_media(char *page, char **start, off_t off, int count, 234 int *eof, void *data) 235 { 236 int len; 237 238 strcpy(page, "disk\n"); 239 len = strlen("disk\n"); 240 len -= off; 241 if (len < count){ 242 *eof = 1; 243 if (len <= 0) return 0; 244 } 245 else len = count; 246 *start = page + off; 247 return len; 248 } 249 250 static void make_ide_entries(char *dev_name) 251 { 252 struct proc_dir_entry *dir, *ent; 253 char name[64]; 254 255 if(proc_ide_root == NULL) make_proc_ide(); 256 257 dir = proc_mkdir(dev_name, proc_ide); 258 if(!dir) return; 259 260 ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir); 261 if(!ent) return; 262 ent->nlink = 1; 263 ent->data = NULL; 264 ent->read_proc = proc_ide_read_media; 265 ent->write_proc = NULL; 266 sprintf(name,"ide0/%s", dev_name); 267 proc_symlink(dev_name, proc_ide_root, name); 268 } 269 270 static int fake_ide_setup(char *str) 271 { 272 fake_ide = 1; 273 return(1); 274 } 275 276 __setup("fake_ide", fake_ide_setup); 277 278 __uml_help(fake_ide_setup, 279 "fake_ide\n" 280 " Create ide0 entries that map onto ubd devices.\n\n" 281 ); 282 283 static int parse_unit(char **ptr) 284 { 285 char *str = *ptr, *end; 286 int n = -1; 287 288 if(isdigit(*str)) { 289 n = simple_strtoul(str, &end, 0); 290 if(end == str) 291 return(-1); 292 *ptr = end; 293 } 294 else if (('a' <= *str) && (*str <= 'h')) { 295 n = *str - 'a'; 296 str++; 297 *ptr = str; 298 } 299 return(n); 300 } 301 302 static int ubd_setup_common(char *str, int *index_out) 303 { 304 struct ubd *dev; 305 struct openflags flags = global_openflags; 306 char *backing_file; 307 int n, err, i; 308 309 if(index_out) *index_out = -1; 310 n = *str; 311 if(n == '='){ 312 char *end; 313 int major; 314 315 str++; 316 if(!strcmp(str, "mmap")){ 317 CHOOSE_MODE(printk("mmap not supported by the ubd " 318 "driver in tt mode\n"), 319 ubd_do_mmap = 1); 320 return(0); 321 } 322 323 if(!strcmp(str, "sync")){ 324 global_openflags = of_sync(global_openflags); 325 return(0); 326 } 327 major = simple_strtoul(str, &end, 0); 328 if((*end != '\0') || (end == str)){ 329 printk(KERN_ERR 330 "ubd_setup : didn't parse major number\n"); 331 return(1); 332 } 333 334 err = 1; 335 spin_lock(&ubd_lock); 336 if(fake_major != MAJOR_NR){ 337 printk(KERN_ERR "Can't assign a fake major twice\n"); 338 goto out1; 339 } 340 341 fake_major = major; 342 343 printk(KERN_INFO "Setting extra ubd major number to %d\n", 344 major); 345 err = 0; 346 out1: 347 spin_unlock(&ubd_lock); 348 return(err); 349 } 350 351 n = parse_unit(&str); 352 if(n < 0){ 353 printk(KERN_ERR "ubd_setup : couldn't parse unit number " 354 "'%s'\n", str); 355 return(1); 356 } 357 if(n >= MAX_DEV){ 358 printk(KERN_ERR "ubd_setup : index %d out of range " 359 "(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1); 360 return(1); 361 } 362 363 err = 1; 364 spin_lock(&ubd_lock); 365 366 dev = &ubd_dev[n]; 367 if(dev->file != NULL){ 368 printk(KERN_ERR "ubd_setup : device already configured\n"); 369 goto out; 370 } 371 372 if (index_out) 373 *index_out = n; 374 375 for (i = 0; i < 4; i++) { 376 switch (*str) { 377 case 'r': 378 flags.w = 0; 379 break; 380 case 's': 381 flags.s = 1; 382 break; 383 case 'd': 384 dev->no_cow = 1; 385 break; 386 case '=': 387 str++; 388 goto break_loop; 389 default: 390 printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r,s or d)\n"); 391 goto out; 392 } 393 str++; 394 } 395 396 if (*str == '=') 397 printk(KERN_ERR "ubd_setup : Too many flags specified\n"); 398 else 399 printk(KERN_ERR "ubd_setup : Expected '='\n"); 400 goto out; 401 402 break_loop: 403 err = 0; 404 backing_file = strchr(str, ','); 405 406 if (!backing_file) { 407 backing_file = strchr(str, ':'); 408 } 409 410 if(backing_file){ 411 if(dev->no_cow) 412 printk(KERN_ERR "Can't specify both 'd' and a " 413 "cow file\n"); 414 else { 415 *backing_file = '\0'; 416 backing_file++; 417 } 418 } 419 dev->file = str; 420 dev->cow.file = backing_file; 421 dev->boot_openflags = flags; 422 out: 423 spin_unlock(&ubd_lock); 424 return(err); 425 } 426 427 static int ubd_setup(char *str) 428 { 429 ubd_setup_common(str, NULL); 430 return(1); 431 } 432 433 __setup("ubd", ubd_setup); 434 __uml_help(ubd_setup, 435 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" 436 " This is used to associate a device with a file in the underlying\n" 437 " filesystem. When specifying two filenames, the first one is the\n" 438 " COW name and the second is the backing file name. As separator you can\n" 439 " use either a ':' or a ',': the first one allows writing things like;\n" 440 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 441 " while with a ',' the shell would not expand the 2nd '~'.\n" 442 " When using only one filename, UML will detect whether to thread it like\n" 443 " a COW file or a backing file. To override this detection, add the 'd'\n" 444 " flag:\n" 445 " ubd0d=BackingFile\n" 446 " Usually, there is a filesystem in the file, but \n" 447 " that's not required. Swap devices containing swap files can be\n" 448 " specified like this. Also, a file which doesn't contain a\n" 449 " filesystem can have its contents read in the virtual \n" 450 " machine by running 'dd' on the device. <n> must be in the range\n" 451 " 0 to 7. Appending an 'r' to the number will cause that device\n" 452 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 453 " an 's' will cause data to be written to disk on the host immediately.\n\n" 454 ); 455 456 static int udb_setup(char *str) 457 { 458 printk("udb%s specified on command line is almost certainly a ubd -> " 459 "udb TYPO\n", str); 460 return(1); 461 } 462 463 __setup("udb", udb_setup); 464 __uml_help(udb_setup, 465 "udb\n" 466 " This option is here solely to catch ubd -> udb typos, which can be\n\n" 467 " to impossible to catch visually unless you specifically look for\n\n" 468 " them. The only result of any option starting with 'udb' is an error\n\n" 469 " in the boot output.\n\n" 470 ); 471 472 static int fakehd_set = 0; 473 static int fakehd(char *str) 474 { 475 printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n"); 476 fakehd_set = 1; 477 return 1; 478 } 479 480 __setup("fakehd", fakehd); 481 __uml_help(fakehd, 482 "fakehd\n" 483 " Change the ubd device name to \"hd\".\n\n" 484 ); 485 486 static void do_ubd_request(request_queue_t * q); 487 488 /* Only changed by ubd_init, which is an initcall. */ 489 int thread_fd = -1; 490 491 /* Changed by ubd_handler, which is serialized because interrupts only 492 * happen on CPU 0. 493 */ 494 int intr_count = 0; 495 496 /* call ubd_finish if you need to serialize */ 497 static void __ubd_finish(struct request *req, int error) 498 { 499 int nsect; 500 501 if(error){ 502 end_request(req, 0); 503 return; 504 } 505 nsect = req->current_nr_sectors; 506 req->sector += nsect; 507 req->buffer += nsect << 9; 508 req->errors = 0; 509 req->nr_sectors -= nsect; 510 req->current_nr_sectors = 0; 511 end_request(req, 1); 512 } 513 514 static inline void ubd_finish(struct request *req, int error) 515 { 516 spin_lock(&ubd_io_lock); 517 __ubd_finish(req, error); 518 spin_unlock(&ubd_io_lock); 519 } 520 521 /* Called without ubd_io_lock held */ 522 static void ubd_handler(void) 523 { 524 struct io_thread_req req; 525 struct request *rq = elv_next_request(ubd_queue); 526 int n, err; 527 528 do_ubd = NULL; 529 intr_count++; 530 n = os_read_file(thread_fd, &req, sizeof(req)); 531 if(n != sizeof(req)){ 532 printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, " 533 "err = %d\n", os_getpid(), -n); 534 spin_lock(&ubd_io_lock); 535 end_request(rq, 0); 536 spin_unlock(&ubd_io_lock); 537 return; 538 } 539 540 if((req.op != UBD_MMAP) && 541 ((req.offset != ((__u64) (rq->sector)) << 9) || 542 (req.length != (rq->current_nr_sectors) << 9))) 543 panic("I/O op mismatch"); 544 545 if(req.map_fd != -1){ 546 err = physmem_subst_mapping(req.buffer, req.map_fd, 547 req.map_offset, 1); 548 if(err) 549 printk("ubd_handler - physmem_subst_mapping failed, " 550 "err = %d\n", -err); 551 } 552 553 ubd_finish(rq, req.error); 554 reactivate_fd(thread_fd, UBD_IRQ); 555 do_ubd_request(ubd_queue); 556 } 557 558 static irqreturn_t ubd_intr(int irq, void *dev, struct pt_regs *unused) 559 { 560 ubd_handler(); 561 return(IRQ_HANDLED); 562 } 563 564 /* Only changed by ubd_init, which is an initcall. */ 565 static int io_pid = -1; 566 567 void kill_io_thread(void) 568 { 569 if(io_pid != -1) 570 os_kill_process(io_pid, 1); 571 } 572 573 __uml_exitcall(kill_io_thread); 574 575 static int ubd_file_size(struct ubd *dev, __u64 *size_out) 576 { 577 char *file; 578 579 file = dev->cow.file ? dev->cow.file : dev->file; 580 return(os_file_size(file, size_out)); 581 } 582 583 static void ubd_close(struct ubd *dev) 584 { 585 if(ubd_do_mmap) 586 physmem_forget_descriptor(dev->fd); 587 os_close_file(dev->fd); 588 if(dev->cow.file == NULL) 589 return; 590 591 if(ubd_do_mmap) 592 physmem_forget_descriptor(dev->cow.fd); 593 os_close_file(dev->cow.fd); 594 vfree(dev->cow.bitmap); 595 dev->cow.bitmap = NULL; 596 } 597 598 static int ubd_open_dev(struct ubd *dev) 599 { 600 struct openflags flags; 601 char **back_ptr; 602 int err, create_cow, *create_ptr; 603 604 dev->openflags = dev->boot_openflags; 605 create_cow = 0; 606 create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL; 607 back_ptr = dev->no_cow ? NULL : &dev->cow.file; 608 dev->fd = open_ubd_file(dev->file, &dev->openflags, back_ptr, 609 &dev->cow.bitmap_offset, &dev->cow.bitmap_len, 610 &dev->cow.data_offset, create_ptr); 611 612 if((dev->fd == -ENOENT) && create_cow){ 613 dev->fd = create_cow_file(dev->file, dev->cow.file, 614 dev->openflags, 1 << 9, PAGE_SIZE, 615 &dev->cow.bitmap_offset, 616 &dev->cow.bitmap_len, 617 &dev->cow.data_offset); 618 if(dev->fd >= 0){ 619 printk(KERN_INFO "Creating \"%s\" as COW file for " 620 "\"%s\"\n", dev->file, dev->cow.file); 621 } 622 } 623 624 if(dev->fd < 0){ 625 printk("Failed to open '%s', errno = %d\n", dev->file, 626 -dev->fd); 627 return(dev->fd); 628 } 629 630 if(dev->cow.file != NULL){ 631 err = -ENOMEM; 632 dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len); 633 if(dev->cow.bitmap == NULL){ 634 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 635 goto error; 636 } 637 flush_tlb_kernel_vm(); 638 639 err = read_cow_bitmap(dev->fd, dev->cow.bitmap, 640 dev->cow.bitmap_offset, 641 dev->cow.bitmap_len); 642 if(err < 0) 643 goto error; 644 645 flags = dev->openflags; 646 flags.w = 0; 647 err = open_ubd_file(dev->cow.file, &flags, NULL, NULL, NULL, 648 NULL, NULL); 649 if(err < 0) goto error; 650 dev->cow.fd = err; 651 } 652 return(0); 653 error: 654 os_close_file(dev->fd); 655 return(err); 656 } 657 658 static int ubd_new_disk(int major, u64 size, int unit, 659 struct gendisk **disk_out) 660 661 { 662 struct gendisk *disk; 663 char from[sizeof("ubd/nnnnn\0")], to[sizeof("discnnnnn/disc\0")]; 664 int err; 665 666 disk = alloc_disk(1 << UBD_SHIFT); 667 if(disk == NULL) 668 return(-ENOMEM); 669 670 disk->major = major; 671 disk->first_minor = unit << UBD_SHIFT; 672 disk->fops = &ubd_blops; 673 set_capacity(disk, size / 512); 674 if(major == MAJOR_NR){ 675 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 676 sprintf(disk->devfs_name, "ubd/disc%d", unit); 677 sprintf(from, "ubd/%d", unit); 678 sprintf(to, "disc%d/disc", unit); 679 err = devfs_mk_symlink(from, to); 680 if(err) 681 printk("ubd_new_disk failed to make link from %s to " 682 "%s, error = %d\n", from, to, err); 683 } 684 else { 685 sprintf(disk->disk_name, "ubd_fake%d", unit); 686 sprintf(disk->devfs_name, "ubd_fake/disc%d", unit); 687 } 688 689 /* sysfs register (not for ide fake devices) */ 690 if (major == MAJOR_NR) { 691 ubd_dev[unit].pdev.id = unit; 692 ubd_dev[unit].pdev.name = DRIVER_NAME; 693 platform_device_register(&ubd_dev[unit].pdev); 694 disk->driverfs_dev = &ubd_dev[unit].pdev.dev; 695 } 696 697 disk->private_data = &ubd_dev[unit]; 698 disk->queue = ubd_queue; 699 add_disk(disk); 700 701 *disk_out = disk; 702 return 0; 703 } 704 705 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9)) 706 707 static int ubd_add(int n) 708 { 709 struct ubd *dev = &ubd_dev[n]; 710 int err; 711 712 if(dev->file == NULL) 713 return(-ENODEV); 714 715 if (ubd_open_dev(dev)) 716 return(-ENODEV); 717 718 err = ubd_file_size(dev, &dev->size); 719 if(err < 0) 720 return(err); 721 722 dev->size = ROUND_BLOCK(dev->size); 723 724 err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]); 725 if(err) 726 return(err); 727 728 if(fake_major != MAJOR_NR) 729 ubd_new_disk(fake_major, dev->size, n, 730 &fake_gendisk[n]); 731 732 /* perhaps this should also be under the "if (fake_major)" above */ 733 /* using the fake_disk->disk_name and also the fakehd_set name */ 734 if (fake_ide) 735 make_ide_entries(ubd_gendisk[n]->disk_name); 736 737 ubd_close(dev); 738 return 0; 739 } 740 741 static int ubd_config(char *str) 742 { 743 int n, err; 744 745 str = uml_strdup(str); 746 if(str == NULL){ 747 printk(KERN_ERR "ubd_config failed to strdup string\n"); 748 return(1); 749 } 750 err = ubd_setup_common(str, &n); 751 if(err){ 752 kfree(str); 753 return(-1); 754 } 755 if(n == -1) return(0); 756 757 spin_lock(&ubd_lock); 758 err = ubd_add(n); 759 if(err) 760 ubd_dev[n].file = NULL; 761 spin_unlock(&ubd_lock); 762 763 return(err); 764 } 765 766 static int ubd_get_config(char *name, char *str, int size, char **error_out) 767 { 768 struct ubd *dev; 769 int n, len = 0; 770 771 n = parse_unit(&name); 772 if((n >= MAX_DEV) || (n < 0)){ 773 *error_out = "ubd_get_config : device number out of range"; 774 return(-1); 775 } 776 777 dev = &ubd_dev[n]; 778 spin_lock(&ubd_lock); 779 780 if(dev->file == NULL){ 781 CONFIG_CHUNK(str, size, len, "", 1); 782 goto out; 783 } 784 785 CONFIG_CHUNK(str, size, len, dev->file, 0); 786 787 if(dev->cow.file != NULL){ 788 CONFIG_CHUNK(str, size, len, ",", 0); 789 CONFIG_CHUNK(str, size, len, dev->cow.file, 1); 790 } 791 else CONFIG_CHUNK(str, size, len, "", 1); 792 793 out: 794 spin_unlock(&ubd_lock); 795 return(len); 796 } 797 798 static int ubd_remove(char *str) 799 { 800 struct ubd *dev; 801 int n, err = -ENODEV; 802 803 n = parse_unit(&str); 804 805 if((n < 0) || (n >= MAX_DEV)) 806 return(err); 807 808 dev = &ubd_dev[n]; 809 if(dev->count > 0) 810 return(-EBUSY); /* you cannot remove a open disk */ 811 812 err = 0; 813 spin_lock(&ubd_lock); 814 815 if(ubd_gendisk[n] == NULL) 816 goto out; 817 818 del_gendisk(ubd_gendisk[n]); 819 put_disk(ubd_gendisk[n]); 820 ubd_gendisk[n] = NULL; 821 822 if(fake_gendisk[n] != NULL){ 823 del_gendisk(fake_gendisk[n]); 824 put_disk(fake_gendisk[n]); 825 fake_gendisk[n] = NULL; 826 } 827 828 platform_device_unregister(&dev->pdev); 829 *dev = ((struct ubd) DEFAULT_UBD); 830 err = 0; 831 out: 832 spin_unlock(&ubd_lock); 833 return(err); 834 } 835 836 static struct mc_device ubd_mc = { 837 .name = "ubd", 838 .config = ubd_config, 839 .get_config = ubd_get_config, 840 .remove = ubd_remove, 841 }; 842 843 static int ubd_mc_init(void) 844 { 845 mconsole_register_dev(&ubd_mc); 846 return 0; 847 } 848 849 __initcall(ubd_mc_init); 850 851 static struct device_driver ubd_driver = { 852 .name = DRIVER_NAME, 853 .bus = &platform_bus_type, 854 }; 855 856 int ubd_init(void) 857 { 858 int i; 859 860 devfs_mk_dir("ubd"); 861 if (register_blkdev(MAJOR_NR, "ubd")) 862 return -1; 863 864 ubd_queue = blk_init_queue(do_ubd_request, &ubd_io_lock); 865 if (!ubd_queue) { 866 unregister_blkdev(MAJOR_NR, "ubd"); 867 return -1; 868 } 869 870 if (fake_major != MAJOR_NR) { 871 char name[sizeof("ubd_nnn\0")]; 872 873 snprintf(name, sizeof(name), "ubd_%d", fake_major); 874 devfs_mk_dir(name); 875 if (register_blkdev(fake_major, "ubd")) 876 return -1; 877 } 878 driver_register(&ubd_driver); 879 for (i = 0; i < MAX_DEV; i++) 880 ubd_add(i); 881 return 0; 882 } 883 884 late_initcall(ubd_init); 885 886 int ubd_driver_init(void){ 887 unsigned long stack; 888 int err; 889 890 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 891 if(global_openflags.s){ 892 printk(KERN_INFO "ubd: Synchronous mode\n"); 893 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 894 * enough. So use anyway the io thread. */ 895 } 896 stack = alloc_stack(0, 0); 897 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), 898 &thread_fd); 899 if(io_pid < 0){ 900 printk(KERN_ERR 901 "ubd : Failed to start I/O thread (errno = %d) - " 902 "falling back to synchronous I/O\n", -io_pid); 903 io_pid = -1; 904 return(0); 905 } 906 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 907 SA_INTERRUPT, "ubd", ubd_dev); 908 if(err != 0) 909 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 910 return(err); 911 } 912 913 device_initcall(ubd_driver_init); 914 915 static int ubd_open(struct inode *inode, struct file *filp) 916 { 917 struct gendisk *disk = inode->i_bdev->bd_disk; 918 struct ubd *dev = disk->private_data; 919 int err = 0; 920 921 if(dev->count == 0){ 922 err = ubd_open_dev(dev); 923 if(err){ 924 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 925 disk->disk_name, dev->file, -err); 926 goto out; 927 } 928 } 929 dev->count++; 930 if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){ 931 if(--dev->count == 0) ubd_close(dev); 932 err = -EROFS; 933 } 934 out: 935 return(err); 936 } 937 938 static int ubd_release(struct inode * inode, struct file * file) 939 { 940 struct gendisk *disk = inode->i_bdev->bd_disk; 941 struct ubd *dev = disk->private_data; 942 943 if(--dev->count == 0) 944 ubd_close(dev); 945 return(0); 946 } 947 948 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 949 __u64 *cow_offset, unsigned long *bitmap, 950 __u64 bitmap_offset, unsigned long *bitmap_words, 951 __u64 bitmap_len) 952 { 953 __u64 sector = io_offset >> 9; 954 int i, update_bitmap = 0; 955 956 for(i = 0; i < length >> 9; i++){ 957 if(cow_mask != NULL) 958 ubd_set_bit(i, (unsigned char *) cow_mask); 959 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 960 continue; 961 962 update_bitmap = 1; 963 ubd_set_bit(sector + i, (unsigned char *) bitmap); 964 } 965 966 if(!update_bitmap) 967 return; 968 969 *cow_offset = sector / (sizeof(unsigned long) * 8); 970 971 /* This takes care of the case where we're exactly at the end of the 972 * device, and *cow_offset + 1 is off the end. So, just back it up 973 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 974 * for the original diagnosis. 975 */ 976 if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) / 977 sizeof(unsigned long) - 1)) 978 (*cow_offset)--; 979 980 bitmap_words[0] = bitmap[*cow_offset]; 981 bitmap_words[1] = bitmap[*cow_offset + 1]; 982 983 *cow_offset *= sizeof(unsigned long); 984 *cow_offset += bitmap_offset; 985 } 986 987 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, 988 __u64 bitmap_offset, __u64 bitmap_len) 989 { 990 __u64 sector = req->offset >> 9; 991 int i; 992 993 if(req->length > (sizeof(req->sector_mask) * 8) << 9) 994 panic("Operation too long"); 995 996 if(req->op == UBD_READ) { 997 for(i = 0; i < req->length >> 9; i++){ 998 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 999 ubd_set_bit(i, (unsigned char *) 1000 &req->sector_mask); 1001 } 1002 } 1003 else cowify_bitmap(req->offset, req->length, &req->sector_mask, 1004 &req->cow_offset, bitmap, bitmap_offset, 1005 req->bitmap_words, bitmap_len); 1006 } 1007 1008 static int mmap_fd(struct request *req, struct ubd *dev, __u64 offset) 1009 { 1010 __u64 sector; 1011 unsigned char *bitmap; 1012 int bit, i; 1013 1014 /* mmap must have been requested on the command line */ 1015 if(!ubd_do_mmap) 1016 return(-1); 1017 1018 /* The buffer must be page aligned */ 1019 if(((unsigned long) req->buffer % UBD_MMAP_BLOCK_SIZE) != 0) 1020 return(-1); 1021 1022 /* The request must be a page long */ 1023 if((req->current_nr_sectors << 9) != PAGE_SIZE) 1024 return(-1); 1025 1026 if(dev->cow.file == NULL) 1027 return(dev->fd); 1028 1029 sector = offset >> 9; 1030 bitmap = (unsigned char *) dev->cow.bitmap; 1031 bit = ubd_test_bit(sector, bitmap); 1032 1033 for(i = 1; i < req->current_nr_sectors; i++){ 1034 if(ubd_test_bit(sector + i, bitmap) != bit) 1035 return(-1); 1036 } 1037 1038 if(bit || (rq_data_dir(req) == WRITE)) 1039 offset += dev->cow.data_offset; 1040 1041 /* The data on disk must be page aligned */ 1042 if((offset % UBD_MMAP_BLOCK_SIZE) != 0) 1043 return(-1); 1044 1045 return(bit ? dev->fd : dev->cow.fd); 1046 } 1047 1048 static int prepare_mmap_request(struct ubd *dev, int fd, __u64 offset, 1049 struct request *req, 1050 struct io_thread_req *io_req) 1051 { 1052 int err; 1053 1054 if(rq_data_dir(req) == WRITE){ 1055 /* Writes are almost no-ops since the new data is already in the 1056 * host page cache 1057 */ 1058 dev->map_writes++; 1059 if(dev->cow.file != NULL) 1060 cowify_bitmap(io_req->offset, io_req->length, 1061 &io_req->sector_mask, &io_req->cow_offset, 1062 dev->cow.bitmap, dev->cow.bitmap_offset, 1063 io_req->bitmap_words, 1064 dev->cow.bitmap_len); 1065 } 1066 else { 1067 int w; 1068 1069 if((dev->cow.file != NULL) && (fd == dev->cow.fd)) 1070 w = 0; 1071 else w = dev->openflags.w; 1072 1073 if((dev->cow.file != NULL) && (fd == dev->fd)) 1074 offset += dev->cow.data_offset; 1075 1076 err = physmem_subst_mapping(req->buffer, fd, offset, w); 1077 if(err){ 1078 printk("physmem_subst_mapping failed, err = %d\n", 1079 -err); 1080 return(1); 1081 } 1082 dev->map_reads++; 1083 } 1084 io_req->op = UBD_MMAP; 1085 io_req->buffer = req->buffer; 1086 return(0); 1087 } 1088 1089 /* Called with ubd_io_lock held */ 1090 static int prepare_request(struct request *req, struct io_thread_req *io_req) 1091 { 1092 struct gendisk *disk = req->rq_disk; 1093 struct ubd *dev = disk->private_data; 1094 __u64 offset; 1095 int len, fd; 1096 1097 if(req->rq_status == RQ_INACTIVE) return(1); 1098 1099 if((rq_data_dir(req) == WRITE) && !dev->openflags.w){ 1100 printk("Write attempted on readonly ubd device %s\n", 1101 disk->disk_name); 1102 end_request(req, 0); 1103 return(1); 1104 } 1105 1106 offset = ((__u64) req->sector) << 9; 1107 len = req->current_nr_sectors << 9; 1108 1109 io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd; 1110 io_req->fds[1] = dev->fd; 1111 io_req->map_fd = -1; 1112 io_req->cow_offset = -1; 1113 io_req->offset = offset; 1114 io_req->length = len; 1115 io_req->error = 0; 1116 io_req->sector_mask = 0; 1117 1118 fd = mmap_fd(req, dev, io_req->offset); 1119 if(fd > 0){ 1120 /* If mmapping is otherwise OK, but the first access to the 1121 * page is a write, then it's not mapped in yet. So we have 1122 * to write the data to disk first, then we can map the disk 1123 * page in and continue normally from there. 1124 */ 1125 if((rq_data_dir(req) == WRITE) && !is_remapped(req->buffer)){ 1126 io_req->map_fd = dev->fd; 1127 io_req->map_offset = io_req->offset + 1128 dev->cow.data_offset; 1129 dev->write_maps++; 1130 } 1131 else return(prepare_mmap_request(dev, fd, io_req->offset, req, 1132 io_req)); 1133 } 1134 1135 if(rq_data_dir(req) == READ) 1136 dev->nomap_reads++; 1137 else dev->nomap_writes++; 1138 1139 io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; 1140 io_req->offsets[0] = 0; 1141 io_req->offsets[1] = dev->cow.data_offset; 1142 io_req->buffer = req->buffer; 1143 io_req->sectorsize = 1 << 9; 1144 1145 if(dev->cow.file != NULL) 1146 cowify_req(io_req, dev->cow.bitmap, dev->cow.bitmap_offset, 1147 dev->cow.bitmap_len); 1148 1149 return(0); 1150 } 1151 1152 /* Called with ubd_io_lock held */ 1153 static void do_ubd_request(request_queue_t *q) 1154 { 1155 struct io_thread_req io_req; 1156 struct request *req; 1157 int err, n; 1158 1159 if(thread_fd == -1){ 1160 while((req = elv_next_request(q)) != NULL){ 1161 err = prepare_request(req, &io_req); 1162 if(!err){ 1163 do_io(&io_req); 1164 __ubd_finish(req, io_req.error); 1165 } 1166 } 1167 } 1168 else { 1169 if(do_ubd || (req = elv_next_request(q)) == NULL) 1170 return; 1171 err = prepare_request(req, &io_req); 1172 if(!err){ 1173 do_ubd = ubd_handler; 1174 n = os_write_file(thread_fd, (char *) &io_req, 1175 sizeof(io_req)); 1176 if(n != sizeof(io_req)) 1177 printk("write to io thread failed, " 1178 "errno = %d\n", -n); 1179 } 1180 } 1181 } 1182 1183 static int ubd_ioctl(struct inode * inode, struct file * file, 1184 unsigned int cmd, unsigned long arg) 1185 { 1186 struct hd_geometry __user *loc = (struct hd_geometry __user *) arg; 1187 struct ubd *dev = inode->i_bdev->bd_disk->private_data; 1188 struct hd_driveid ubd_id = { 1189 .cyls = 0, 1190 .heads = 128, 1191 .sectors = 32, 1192 }; 1193 1194 switch (cmd) { 1195 struct hd_geometry g; 1196 struct cdrom_volctrl volume; 1197 case HDIO_GETGEO: 1198 if(!loc) return(-EINVAL); 1199 g.heads = 128; 1200 g.sectors = 32; 1201 g.cylinders = dev->size / (128 * 32 * 512); 1202 g.start = get_start_sect(inode->i_bdev); 1203 return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0); 1204 1205 case HDIO_GET_IDENTITY: 1206 ubd_id.cyls = dev->size / (128 * 32 * 512); 1207 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1208 sizeof(ubd_id))) 1209 return(-EFAULT); 1210 return(0); 1211 1212 case CDROMVOLREAD: 1213 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1214 return(-EFAULT); 1215 volume.channel0 = 255; 1216 volume.channel1 = 255; 1217 volume.channel2 = 255; 1218 volume.channel3 = 255; 1219 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1220 return(-EFAULT); 1221 return(0); 1222 } 1223 return(-EINVAL); 1224 } 1225 1226 static int ubd_check_remapped(int fd, unsigned long address, int is_write, 1227 __u64 offset) 1228 { 1229 __u64 bitmap_offset; 1230 unsigned long new_bitmap[2]; 1231 int i, err, n; 1232 1233 /* If it's not a write access, we can't do anything about it */ 1234 if(!is_write) 1235 return(0); 1236 1237 /* We have a write */ 1238 for(i = 0; i < sizeof(ubd_dev) / sizeof(ubd_dev[0]); i++){ 1239 struct ubd *dev = &ubd_dev[i]; 1240 1241 if((dev->fd != fd) && (dev->cow.fd != fd)) 1242 continue; 1243 1244 /* It's a write to a ubd device */ 1245 1246 if(!dev->openflags.w){ 1247 /* It's a write access on a read-only device - probably 1248 * shouldn't happen. If the kernel is trying to change 1249 * something with no intention of writing it back out, 1250 * then this message will clue us in that this needs 1251 * fixing 1252 */ 1253 printk("Write access to mapped page from readonly ubd " 1254 "device %d\n", i); 1255 return(0); 1256 } 1257 1258 /* It's a write to a writeable ubd device - it must be COWed 1259 * because, otherwise, the page would have been mapped in 1260 * writeable 1261 */ 1262 1263 if(!dev->cow.file) 1264 panic("Write fault on writeable non-COW ubd device %d", 1265 i); 1266 1267 /* It should also be an access to the backing file since the 1268 * COW pages should be mapped in read-write 1269 */ 1270 1271 if(fd == dev->fd) 1272 panic("Write fault on a backing page of ubd " 1273 "device %d\n", i); 1274 1275 /* So, we do the write, copying the backing data to the COW 1276 * file... 1277 */ 1278 1279 err = os_seek_file(dev->fd, offset + dev->cow.data_offset); 1280 if(err < 0) 1281 panic("Couldn't seek to %lld in COW file of ubd " 1282 "device %d, err = %d", 1283 offset + dev->cow.data_offset, i, -err); 1284 1285 n = os_write_file(dev->fd, (void *) address, PAGE_SIZE); 1286 if(n != PAGE_SIZE) 1287 panic("Couldn't copy data to COW file of ubd " 1288 "device %d, err = %d", i, -n); 1289 1290 /* ... updating the COW bitmap... */ 1291 1292 cowify_bitmap(offset, PAGE_SIZE, NULL, &bitmap_offset, 1293 dev->cow.bitmap, dev->cow.bitmap_offset, 1294 new_bitmap, dev->cow.bitmap_len); 1295 1296 err = os_seek_file(dev->fd, bitmap_offset); 1297 if(err < 0) 1298 panic("Couldn't seek to %lld in COW file of ubd " 1299 "device %d, err = %d", bitmap_offset, i, -err); 1300 1301 n = os_write_file(dev->fd, new_bitmap, sizeof(new_bitmap)); 1302 if(n != sizeof(new_bitmap)) 1303 panic("Couldn't update bitmap of ubd device %d, " 1304 "err = %d", i, -n); 1305 1306 /* Maybe we can map the COW page in, and maybe we can't. If 1307 * it is a pre-V3 COW file, we can't, since the alignment will 1308 * be wrong. If it is a V3 or later COW file which has been 1309 * moved to a system with a larger page size, then maybe we 1310 * can't, depending on the exact location of the page. 1311 */ 1312 1313 offset += dev->cow.data_offset; 1314 1315 /* Remove the remapping, putting the original anonymous page 1316 * back. If the COW file can be mapped in, that is done. 1317 * Otherwise, the COW page is read in. 1318 */ 1319 1320 if(!physmem_remove_mapping((void *) address)) 1321 panic("Address 0x%lx not remapped by ubd device %d", 1322 address, i); 1323 if((offset % UBD_MMAP_BLOCK_SIZE) == 0) 1324 physmem_subst_mapping((void *) address, dev->fd, 1325 offset, 1); 1326 else { 1327 err = os_seek_file(dev->fd, offset); 1328 if(err < 0) 1329 panic("Couldn't seek to %lld in COW file of " 1330 "ubd device %d, err = %d", offset, i, 1331 -err); 1332 1333 n = os_read_file(dev->fd, (void *) address, PAGE_SIZE); 1334 if(n != PAGE_SIZE) 1335 panic("Failed to read page from offset %llx of " 1336 "COW file of ubd device %d, err = %d", 1337 offset, i, -n); 1338 } 1339 1340 return(1); 1341 } 1342 1343 /* It's not a write on a ubd device */ 1344 return(0); 1345 } 1346 1347 static struct remapper ubd_remapper = { 1348 .list = LIST_HEAD_INIT(ubd_remapper.list), 1349 .proc = ubd_check_remapped, 1350 }; 1351 1352 static int ubd_remapper_setup(void) 1353 { 1354 if(ubd_do_mmap) 1355 register_remapper(&ubd_remapper); 1356 1357 return(0); 1358 } 1359 1360 __initcall(ubd_remapper_setup); 1361 1362 static int same_backing_files(char *from_cmdline, char *from_cow, char *cow) 1363 { 1364 struct uml_stat buf1, buf2; 1365 int err; 1366 1367 if(from_cmdline == NULL) return(1); 1368 if(!strcmp(from_cmdline, from_cow)) return(1); 1369 1370 err = os_stat_file(from_cmdline, &buf1); 1371 if(err < 0){ 1372 printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err); 1373 return(1); 1374 } 1375 err = os_stat_file(from_cow, &buf2); 1376 if(err < 0){ 1377 printk("Couldn't stat '%s', err = %d\n", from_cow, -err); 1378 return(1); 1379 } 1380 if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 1381 return(1); 1382 1383 printk("Backing file mismatch - \"%s\" requested,\n" 1384 "\"%s\" specified in COW header of \"%s\"\n", 1385 from_cmdline, from_cow, cow); 1386 return(0); 1387 } 1388 1389 static int backing_file_mismatch(char *file, __u64 size, time_t mtime) 1390 { 1391 unsigned long modtime; 1392 long long actual; 1393 int err; 1394 1395 err = os_file_modtime(file, &modtime); 1396 if(err < 0){ 1397 printk("Failed to get modification time of backing file " 1398 "\"%s\", err = %d\n", file, -err); 1399 return(err); 1400 } 1401 1402 err = os_file_size(file, &actual); 1403 if(err < 0){ 1404 printk("Failed to get size of backing file \"%s\", " 1405 "err = %d\n", file, -err); 1406 return(err); 1407 } 1408 1409 if(actual != size){ 1410 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 1411 * the typecast.*/ 1412 printk("Size mismatch (%llu vs %llu) of COW header vs backing " 1413 "file\n", (unsigned long long) size, actual); 1414 return(-EINVAL); 1415 } 1416 if(modtime != mtime){ 1417 printk("mtime mismatch (%ld vs %ld) of COW header vs backing " 1418 "file\n", mtime, modtime); 1419 return(-EINVAL); 1420 } 1421 return(0); 1422 } 1423 1424 int read_cow_bitmap(int fd, void *buf, int offset, int len) 1425 { 1426 int err; 1427 1428 err = os_seek_file(fd, offset); 1429 if(err < 0) 1430 return(err); 1431 1432 err = os_read_file(fd, buf, len); 1433 if(err < 0) 1434 return(err); 1435 1436 return(0); 1437 } 1438 1439 int open_ubd_file(char *file, struct openflags *openflags, 1440 char **backing_file_out, int *bitmap_offset_out, 1441 unsigned long *bitmap_len_out, int *data_offset_out, 1442 int *create_cow_out) 1443 { 1444 time_t mtime; 1445 unsigned long long size; 1446 __u32 version, align; 1447 char *backing_file; 1448 int fd, err, sectorsize, same, mode = 0644; 1449 1450 fd = os_open_file(file, *openflags, mode); 1451 if(fd < 0){ 1452 if((fd == -ENOENT) && (create_cow_out != NULL)) 1453 *create_cow_out = 1; 1454 if(!openflags->w || 1455 ((fd != -EROFS) && (fd != -EACCES))) return(fd); 1456 openflags->w = 0; 1457 fd = os_open_file(file, *openflags, mode); 1458 if(fd < 0) 1459 return(fd); 1460 } 1461 1462 err = os_lock_file(fd, openflags->w); 1463 if(err < 0){ 1464 printk("Failed to lock '%s', err = %d\n", file, -err); 1465 goto out_close; 1466 } 1467 1468 if(backing_file_out == NULL) return(fd); 1469 1470 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 1471 &size, §orsize, &align, bitmap_offset_out); 1472 if(err && (*backing_file_out != NULL)){ 1473 printk("Failed to read COW header from COW file \"%s\", " 1474 "errno = %d\n", file, -err); 1475 goto out_close; 1476 } 1477 if(err) return(fd); 1478 1479 if(backing_file_out == NULL) return(fd); 1480 1481 same = same_backing_files(*backing_file_out, backing_file, file); 1482 1483 if(!same && !backing_file_mismatch(*backing_file_out, size, mtime)){ 1484 printk("Switching backing file to '%s'\n", *backing_file_out); 1485 err = write_cow_header(file, fd, *backing_file_out, 1486 sectorsize, align, &size); 1487 if(err){ 1488 printk("Switch failed, errno = %d\n", -err); 1489 return(err); 1490 } 1491 } 1492 else { 1493 *backing_file_out = backing_file; 1494 err = backing_file_mismatch(*backing_file_out, size, mtime); 1495 if(err) goto out_close; 1496 } 1497 1498 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 1499 bitmap_len_out, data_offset_out); 1500 1501 return(fd); 1502 out_close: 1503 os_close_file(fd); 1504 return(err); 1505 } 1506 1507 int create_cow_file(char *cow_file, char *backing_file, struct openflags flags, 1508 int sectorsize, int alignment, int *bitmap_offset_out, 1509 unsigned long *bitmap_len_out, int *data_offset_out) 1510 { 1511 int err, fd; 1512 1513 flags.c = 1; 1514 fd = open_ubd_file(cow_file, &flags, NULL, NULL, NULL, NULL, NULL); 1515 if(fd < 0){ 1516 err = fd; 1517 printk("Open of COW file '%s' failed, errno = %d\n", cow_file, 1518 -err); 1519 goto out; 1520 } 1521 1522 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 1523 bitmap_offset_out, bitmap_len_out, 1524 data_offset_out); 1525 if(!err) 1526 return(fd); 1527 os_close_file(fd); 1528 out: 1529 return(err); 1530 } 1531 1532 static int update_bitmap(struct io_thread_req *req) 1533 { 1534 int n; 1535 1536 if(req->cow_offset == -1) 1537 return(0); 1538 1539 n = os_seek_file(req->fds[1], req->cow_offset); 1540 if(n < 0){ 1541 printk("do_io - bitmap lseek failed : err = %d\n", -n); 1542 return(1); 1543 } 1544 1545 n = os_write_file(req->fds[1], &req->bitmap_words, 1546 sizeof(req->bitmap_words)); 1547 if(n != sizeof(req->bitmap_words)){ 1548 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, 1549 req->fds[1]); 1550 return(1); 1551 } 1552 1553 return(0); 1554 } 1555 1556 void do_io(struct io_thread_req *req) 1557 { 1558 char *buf; 1559 unsigned long len; 1560 int n, nsectors, start, end, bit; 1561 int err; 1562 __u64 off; 1563 1564 if(req->op == UBD_MMAP){ 1565 /* Touch the page to force the host to do any necessary IO to 1566 * get it into memory 1567 */ 1568 n = *((volatile int *) req->buffer); 1569 req->error = update_bitmap(req); 1570 return; 1571 } 1572 1573 nsectors = req->length / req->sectorsize; 1574 start = 0; 1575 do { 1576 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); 1577 end = start; 1578 while((end < nsectors) && 1579 (ubd_test_bit(end, (unsigned char *) 1580 &req->sector_mask) == bit)) 1581 end++; 1582 1583 off = req->offset + req->offsets[bit] + 1584 start * req->sectorsize; 1585 len = (end - start) * req->sectorsize; 1586 buf = &req->buffer[start * req->sectorsize]; 1587 1588 err = os_seek_file(req->fds[bit], off); 1589 if(err < 0){ 1590 printk("do_io - lseek failed : err = %d\n", -err); 1591 req->error = 1; 1592 return; 1593 } 1594 if(req->op == UBD_READ){ 1595 n = 0; 1596 do { 1597 buf = &buf[n]; 1598 len -= n; 1599 n = os_read_file(req->fds[bit], buf, len); 1600 if (n < 0) { 1601 printk("do_io - read failed, err = %d " 1602 "fd = %d\n", -n, req->fds[bit]); 1603 req->error = 1; 1604 return; 1605 } 1606 } while((n < len) && (n != 0)); 1607 if (n < len) memset(&buf[n], 0, len - n); 1608 } 1609 else { 1610 n = os_write_file(req->fds[bit], buf, len); 1611 if(n != len){ 1612 printk("do_io - write failed err = %d " 1613 "fd = %d\n", -n, req->fds[bit]); 1614 req->error = 1; 1615 return; 1616 } 1617 } 1618 1619 start = end; 1620 } while(start < nsectors); 1621 1622 req->error = update_bitmap(req); 1623 } 1624 1625 /* Changed in start_io_thread, which is serialized by being called only 1626 * from ubd_init, which is an initcall. 1627 */ 1628 int kernel_fd = -1; 1629 1630 /* Only changed by the io thread */ 1631 int io_count = 0; 1632 1633 int io_thread(void *arg) 1634 { 1635 struct io_thread_req req; 1636 int n; 1637 1638 ignore_sigwinch_sig(); 1639 while(1){ 1640 n = os_read_file(kernel_fd, &req, sizeof(req)); 1641 if(n != sizeof(req)){ 1642 if(n < 0) 1643 printk("io_thread - read failed, fd = %d, " 1644 "err = %d\n", kernel_fd, -n); 1645 else { 1646 printk("io_thread - short read, fd = %d, " 1647 "length = %d\n", kernel_fd, n); 1648 } 1649 continue; 1650 } 1651 io_count++; 1652 do_io(&req); 1653 n = os_write_file(kernel_fd, &req, sizeof(req)); 1654 if(n != sizeof(req)) 1655 printk("io_thread - write failed, fd = %d, err = %d\n", 1656 kernel_fd, -n); 1657 } 1658 } 1659 1660 /* 1661 * Overrides for Emacs so that we follow Linus's tabbing style. 1662 * Emacs will notice this stuff at the end of the file and automatically 1663 * adjust the settings for this buffer only. This must remain at the end 1664 * of the file. 1665 * --------------------------------------------------------------------------- 1666 * Local variables: 1667 * c-file-style: "linux" 1668 * End: 1669 */ 1670