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 /* This is the backing file, actually */ 160 char *file; 161 int fd; 162 unsigned long *bitmap; 163 unsigned long bitmap_len; 164 int bitmap_offset; 165 int data_offset; 166 }; 167 168 struct ubd { 169 char *file; 170 int count; 171 int fd; 172 __u64 size; 173 struct openflags boot_openflags; 174 struct openflags openflags; 175 int no_cow; 176 struct cow cow; 177 struct platform_device pdev; 178 179 int map_writes; 180 int map_reads; 181 int nomap_writes; 182 int nomap_reads; 183 int write_maps; 184 }; 185 186 #define DEFAULT_COW { \ 187 .file = NULL, \ 188 .fd = -1, \ 189 .bitmap = NULL, \ 190 .bitmap_offset = 0, \ 191 .data_offset = 0, \ 192 } 193 194 #define DEFAULT_UBD { \ 195 .file = NULL, \ 196 .count = 0, \ 197 .fd = -1, \ 198 .size = -1, \ 199 .boot_openflags = OPEN_FLAGS, \ 200 .openflags = OPEN_FLAGS, \ 201 .no_cow = 0, \ 202 .cow = DEFAULT_COW, \ 203 .map_writes = 0, \ 204 .map_reads = 0, \ 205 .nomap_writes = 0, \ 206 .nomap_reads = 0, \ 207 .write_maps = 0, \ 208 } 209 210 struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; 211 212 static int ubd0_init(void) 213 { 214 struct ubd *dev = &ubd_dev[0]; 215 216 if(dev->file == NULL) 217 dev->file = "root_fs"; 218 return(0); 219 } 220 221 __initcall(ubd0_init); 222 223 /* Only changed by fake_ide_setup which is a setup */ 224 static int fake_ide = 0; 225 static struct proc_dir_entry *proc_ide_root = NULL; 226 static struct proc_dir_entry *proc_ide = NULL; 227 228 static void make_proc_ide(void) 229 { 230 proc_ide_root = proc_mkdir("ide", NULL); 231 proc_ide = proc_mkdir("ide0", proc_ide_root); 232 } 233 234 static int proc_ide_read_media(char *page, char **start, off_t off, int count, 235 int *eof, void *data) 236 { 237 int len; 238 239 strcpy(page, "disk\n"); 240 len = strlen("disk\n"); 241 len -= off; 242 if (len < count){ 243 *eof = 1; 244 if (len <= 0) return 0; 245 } 246 else len = count; 247 *start = page + off; 248 return len; 249 } 250 251 static void make_ide_entries(char *dev_name) 252 { 253 struct proc_dir_entry *dir, *ent; 254 char name[64]; 255 256 if(proc_ide_root == NULL) make_proc_ide(); 257 258 dir = proc_mkdir(dev_name, proc_ide); 259 if(!dir) return; 260 261 ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir); 262 if(!ent) return; 263 ent->nlink = 1; 264 ent->data = NULL; 265 ent->read_proc = proc_ide_read_media; 266 ent->write_proc = NULL; 267 sprintf(name,"ide0/%s", dev_name); 268 proc_symlink(dev_name, proc_ide_root, name); 269 } 270 271 static int fake_ide_setup(char *str) 272 { 273 fake_ide = 1; 274 return(1); 275 } 276 277 __setup("fake_ide", fake_ide_setup); 278 279 __uml_help(fake_ide_setup, 280 "fake_ide\n" 281 " Create ide0 entries that map onto ubd devices.\n\n" 282 ); 283 284 static int parse_unit(char **ptr) 285 { 286 char *str = *ptr, *end; 287 int n = -1; 288 289 if(isdigit(*str)) { 290 n = simple_strtoul(str, &end, 0); 291 if(end == str) 292 return(-1); 293 *ptr = end; 294 } 295 else if (('a' <= *str) && (*str <= 'h')) { 296 n = *str - 'a'; 297 str++; 298 *ptr = str; 299 } 300 return(n); 301 } 302 303 static int ubd_setup_common(char *str, int *index_out) 304 { 305 struct ubd *dev; 306 struct openflags flags = global_openflags; 307 char *backing_file; 308 int n, err, i; 309 310 if(index_out) *index_out = -1; 311 n = *str; 312 if(n == '='){ 313 char *end; 314 int major; 315 316 str++; 317 if(!strcmp(str, "mmap")){ 318 CHOOSE_MODE(printk("mmap not supported by the ubd " 319 "driver in tt mode\n"), 320 ubd_do_mmap = 1); 321 return(0); 322 } 323 324 if(!strcmp(str, "sync")){ 325 global_openflags = of_sync(global_openflags); 326 return(0); 327 } 328 major = simple_strtoul(str, &end, 0); 329 if((*end != '\0') || (end == str)){ 330 printk(KERN_ERR 331 "ubd_setup : didn't parse major number\n"); 332 return(1); 333 } 334 335 err = 1; 336 spin_lock(&ubd_lock); 337 if(fake_major != MAJOR_NR){ 338 printk(KERN_ERR "Can't assign a fake major twice\n"); 339 goto out1; 340 } 341 342 fake_major = major; 343 344 printk(KERN_INFO "Setting extra ubd major number to %d\n", 345 major); 346 err = 0; 347 out1: 348 spin_unlock(&ubd_lock); 349 return(err); 350 } 351 352 n = parse_unit(&str); 353 if(n < 0){ 354 printk(KERN_ERR "ubd_setup : couldn't parse unit number " 355 "'%s'\n", str); 356 return(1); 357 } 358 if(n >= MAX_DEV){ 359 printk(KERN_ERR "ubd_setup : index %d out of range " 360 "(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1); 361 return(1); 362 } 363 364 err = 1; 365 spin_lock(&ubd_lock); 366 367 dev = &ubd_dev[n]; 368 if(dev->file != NULL){ 369 printk(KERN_ERR "ubd_setup : device already configured\n"); 370 goto out; 371 } 372 373 if (index_out) 374 *index_out = n; 375 376 for (i = 0; i < 4; i++) { 377 switch (*str) { 378 case 'r': 379 flags.w = 0; 380 break; 381 case 's': 382 flags.s = 1; 383 break; 384 case 'd': 385 dev->no_cow = 1; 386 break; 387 case '=': 388 str++; 389 goto break_loop; 390 default: 391 printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r,s or d)\n"); 392 goto out; 393 } 394 str++; 395 } 396 397 if (*str == '=') 398 printk(KERN_ERR "ubd_setup : Too many flags specified\n"); 399 else 400 printk(KERN_ERR "ubd_setup : Expected '='\n"); 401 goto out; 402 403 break_loop: 404 err = 0; 405 backing_file = strchr(str, ','); 406 407 if (!backing_file) { 408 backing_file = strchr(str, ':'); 409 } 410 411 if(backing_file){ 412 if(dev->no_cow) 413 printk(KERN_ERR "Can't specify both 'd' and a " 414 "cow file\n"); 415 else { 416 *backing_file = '\0'; 417 backing_file++; 418 } 419 } 420 dev->file = str; 421 dev->cow.file = backing_file; 422 dev->boot_openflags = flags; 423 out: 424 spin_unlock(&ubd_lock); 425 return(err); 426 } 427 428 static int ubd_setup(char *str) 429 { 430 ubd_setup_common(str, NULL); 431 return(1); 432 } 433 434 __setup("ubd", ubd_setup); 435 __uml_help(ubd_setup, 436 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" 437 " This is used to associate a device with a file in the underlying\n" 438 " filesystem. When specifying two filenames, the first one is the\n" 439 " COW name and the second is the backing file name. As separator you can\n" 440 " use either a ':' or a ',': the first one allows writing things like;\n" 441 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 442 " while with a ',' the shell would not expand the 2nd '~'.\n" 443 " When using only one filename, UML will detect whether to thread it like\n" 444 " a COW file or a backing file. To override this detection, add the 'd'\n" 445 " flag:\n" 446 " ubd0d=BackingFile\n" 447 " Usually, there is a filesystem in the file, but \n" 448 " that's not required. Swap devices containing swap files can be\n" 449 " specified like this. Also, a file which doesn't contain a\n" 450 " filesystem can have its contents read in the virtual \n" 451 " machine by running 'dd' on the device. <n> must be in the range\n" 452 " 0 to 7. Appending an 'r' to the number will cause that device\n" 453 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 454 " an 's' will cause data to be written to disk on the host immediately.\n\n" 455 ); 456 457 static int udb_setup(char *str) 458 { 459 printk("udb%s specified on command line is almost certainly a ubd -> " 460 "udb TYPO\n", str); 461 return(1); 462 } 463 464 __setup("udb", udb_setup); 465 __uml_help(udb_setup, 466 "udb\n" 467 " This option is here solely to catch ubd -> udb typos, which can be\n\n" 468 " to impossible to catch visually unless you specifically look for\n\n" 469 " them. The only result of any option starting with 'udb' is an error\n\n" 470 " in the boot output.\n\n" 471 ); 472 473 static int fakehd_set = 0; 474 static int fakehd(char *str) 475 { 476 printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n"); 477 fakehd_set = 1; 478 return 1; 479 } 480 481 __setup("fakehd", fakehd); 482 __uml_help(fakehd, 483 "fakehd\n" 484 " Change the ubd device name to \"hd\".\n\n" 485 ); 486 487 static void do_ubd_request(request_queue_t * q); 488 489 /* Only changed by ubd_init, which is an initcall. */ 490 int thread_fd = -1; 491 492 /* Changed by ubd_handler, which is serialized because interrupts only 493 * happen on CPU 0. 494 */ 495 int intr_count = 0; 496 497 /* call ubd_finish if you need to serialize */ 498 static void __ubd_finish(struct request *req, int error) 499 { 500 int nsect; 501 502 if(error){ 503 end_request(req, 0); 504 return; 505 } 506 nsect = req->current_nr_sectors; 507 req->sector += nsect; 508 req->buffer += nsect << 9; 509 req->errors = 0; 510 req->nr_sectors -= nsect; 511 req->current_nr_sectors = 0; 512 end_request(req, 1); 513 } 514 515 static inline void ubd_finish(struct request *req, int error) 516 { 517 spin_lock(&ubd_io_lock); 518 __ubd_finish(req, error); 519 spin_unlock(&ubd_io_lock); 520 } 521 522 /* Called without ubd_io_lock held */ 523 static void ubd_handler(void) 524 { 525 struct io_thread_req req; 526 struct request *rq = elv_next_request(ubd_queue); 527 int n, err; 528 529 do_ubd = NULL; 530 intr_count++; 531 n = os_read_file(thread_fd, &req, sizeof(req)); 532 if(n != sizeof(req)){ 533 printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, " 534 "err = %d\n", os_getpid(), -n); 535 spin_lock(&ubd_io_lock); 536 end_request(rq, 0); 537 spin_unlock(&ubd_io_lock); 538 return; 539 } 540 541 if((req.op != UBD_MMAP) && 542 ((req.offset != ((__u64) (rq->sector)) << 9) || 543 (req.length != (rq->current_nr_sectors) << 9))) 544 panic("I/O op mismatch"); 545 546 if(req.map_fd != -1){ 547 err = physmem_subst_mapping(req.buffer, req.map_fd, 548 req.map_offset, 1); 549 if(err) 550 printk("ubd_handler - physmem_subst_mapping failed, " 551 "err = %d\n", -err); 552 } 553 554 ubd_finish(rq, req.error); 555 reactivate_fd(thread_fd, UBD_IRQ); 556 do_ubd_request(ubd_queue); 557 } 558 559 static irqreturn_t ubd_intr(int irq, void *dev, struct pt_regs *unused) 560 { 561 ubd_handler(); 562 return(IRQ_HANDLED); 563 } 564 565 /* Only changed by ubd_init, which is an initcall. */ 566 static int io_pid = -1; 567 568 void kill_io_thread(void) 569 { 570 if(io_pid != -1) 571 os_kill_process(io_pid, 1); 572 } 573 574 __uml_exitcall(kill_io_thread); 575 576 static int ubd_file_size(struct ubd *dev, __u64 *size_out) 577 { 578 char *file; 579 580 file = dev->cow.file ? dev->cow.file : dev->file; 581 return(os_file_size(file, size_out)); 582 } 583 584 static void ubd_close(struct ubd *dev) 585 { 586 if(ubd_do_mmap) 587 physmem_forget_descriptor(dev->fd); 588 os_close_file(dev->fd); 589 if(dev->cow.file == NULL) 590 return; 591 592 if(ubd_do_mmap) 593 physmem_forget_descriptor(dev->cow.fd); 594 os_close_file(dev->cow.fd); 595 vfree(dev->cow.bitmap); 596 dev->cow.bitmap = NULL; 597 } 598 599 static int ubd_open_dev(struct ubd *dev) 600 { 601 struct openflags flags; 602 char **back_ptr; 603 int err, create_cow, *create_ptr; 604 605 dev->openflags = dev->boot_openflags; 606 create_cow = 0; 607 create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL; 608 back_ptr = dev->no_cow ? NULL : &dev->cow.file; 609 dev->fd = open_ubd_file(dev->file, &dev->openflags, back_ptr, 610 &dev->cow.bitmap_offset, &dev->cow.bitmap_len, 611 &dev->cow.data_offset, create_ptr); 612 613 if((dev->fd == -ENOENT) && create_cow){ 614 dev->fd = create_cow_file(dev->file, dev->cow.file, 615 dev->openflags, 1 << 9, PAGE_SIZE, 616 &dev->cow.bitmap_offset, 617 &dev->cow.bitmap_len, 618 &dev->cow.data_offset); 619 if(dev->fd >= 0){ 620 printk(KERN_INFO "Creating \"%s\" as COW file for " 621 "\"%s\"\n", dev->file, dev->cow.file); 622 } 623 } 624 625 if(dev->fd < 0){ 626 printk("Failed to open '%s', errno = %d\n", dev->file, 627 -dev->fd); 628 return(dev->fd); 629 } 630 631 if(dev->cow.file != NULL){ 632 err = -ENOMEM; 633 dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len); 634 if(dev->cow.bitmap == NULL){ 635 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 636 goto error; 637 } 638 flush_tlb_kernel_vm(); 639 640 err = read_cow_bitmap(dev->fd, dev->cow.bitmap, 641 dev->cow.bitmap_offset, 642 dev->cow.bitmap_len); 643 if(err < 0) 644 goto error; 645 646 flags = dev->openflags; 647 flags.w = 0; 648 err = open_ubd_file(dev->cow.file, &flags, NULL, NULL, NULL, 649 NULL, NULL); 650 if(err < 0) goto error; 651 dev->cow.fd = err; 652 } 653 return(0); 654 error: 655 os_close_file(dev->fd); 656 return(err); 657 } 658 659 static int ubd_new_disk(int major, u64 size, int unit, 660 struct gendisk **disk_out) 661 662 { 663 struct gendisk *disk; 664 char from[sizeof("ubd/nnnnn\0")], to[sizeof("discnnnnn/disc\0")]; 665 int err; 666 667 disk = alloc_disk(1 << UBD_SHIFT); 668 if(disk == NULL) 669 return(-ENOMEM); 670 671 disk->major = major; 672 disk->first_minor = unit << UBD_SHIFT; 673 disk->fops = &ubd_blops; 674 set_capacity(disk, size / 512); 675 if(major == MAJOR_NR){ 676 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 677 sprintf(disk->devfs_name, "ubd/disc%d", unit); 678 sprintf(from, "ubd/%d", unit); 679 sprintf(to, "disc%d/disc", unit); 680 err = devfs_mk_symlink(from, to); 681 if(err) 682 printk("ubd_new_disk failed to make link from %s to " 683 "%s, error = %d\n", from, to, err); 684 } 685 else { 686 sprintf(disk->disk_name, "ubd_fake%d", unit); 687 sprintf(disk->devfs_name, "ubd_fake/disc%d", unit); 688 } 689 690 /* sysfs register (not for ide fake devices) */ 691 if (major == MAJOR_NR) { 692 ubd_dev[unit].pdev.id = unit; 693 ubd_dev[unit].pdev.name = DRIVER_NAME; 694 platform_device_register(&ubd_dev[unit].pdev); 695 disk->driverfs_dev = &ubd_dev[unit].pdev.dev; 696 } 697 698 disk->private_data = &ubd_dev[unit]; 699 disk->queue = ubd_queue; 700 add_disk(disk); 701 702 *disk_out = disk; 703 return 0; 704 } 705 706 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9)) 707 708 static int ubd_add(int n) 709 { 710 struct ubd *dev = &ubd_dev[n]; 711 int err; 712 713 if(dev->file == NULL) 714 return(-ENODEV); 715 716 if (ubd_open_dev(dev)) 717 return(-ENODEV); 718 719 err = ubd_file_size(dev, &dev->size); 720 if(err < 0) 721 return(err); 722 723 dev->size = ROUND_BLOCK(dev->size); 724 725 err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]); 726 if(err) 727 return(err); 728 729 if(fake_major != MAJOR_NR) 730 ubd_new_disk(fake_major, dev->size, n, 731 &fake_gendisk[n]); 732 733 /* perhaps this should also be under the "if (fake_major)" above */ 734 /* using the fake_disk->disk_name and also the fakehd_set name */ 735 if (fake_ide) 736 make_ide_entries(ubd_gendisk[n]->disk_name); 737 738 ubd_close(dev); 739 return 0; 740 } 741 742 static int ubd_config(char *str) 743 { 744 int n, err; 745 746 str = uml_strdup(str); 747 if(str == NULL){ 748 printk(KERN_ERR "ubd_config failed to strdup string\n"); 749 return(1); 750 } 751 err = ubd_setup_common(str, &n); 752 if(err){ 753 kfree(str); 754 return(-1); 755 } 756 if(n == -1) return(0); 757 758 spin_lock(&ubd_lock); 759 err = ubd_add(n); 760 if(err) 761 ubd_dev[n].file = NULL; 762 spin_unlock(&ubd_lock); 763 764 return(err); 765 } 766 767 static int ubd_get_config(char *name, char *str, int size, char **error_out) 768 { 769 struct ubd *dev; 770 int n, len = 0; 771 772 n = parse_unit(&name); 773 if((n >= MAX_DEV) || (n < 0)){ 774 *error_out = "ubd_get_config : device number out of range"; 775 return(-1); 776 } 777 778 dev = &ubd_dev[n]; 779 spin_lock(&ubd_lock); 780 781 if(dev->file == NULL){ 782 CONFIG_CHUNK(str, size, len, "", 1); 783 goto out; 784 } 785 786 CONFIG_CHUNK(str, size, len, dev->file, 0); 787 788 if(dev->cow.file != NULL){ 789 CONFIG_CHUNK(str, size, len, ",", 0); 790 CONFIG_CHUNK(str, size, len, dev->cow.file, 1); 791 } 792 else CONFIG_CHUNK(str, size, len, "", 1); 793 794 out: 795 spin_unlock(&ubd_lock); 796 return(len); 797 } 798 799 static int ubd_remove(char *str) 800 { 801 struct ubd *dev; 802 int n, err = -ENODEV; 803 804 n = parse_unit(&str); 805 806 if((n < 0) || (n >= MAX_DEV)) 807 return(err); 808 809 dev = &ubd_dev[n]; 810 if(dev->count > 0) 811 return(-EBUSY); /* you cannot remove a open disk */ 812 813 err = 0; 814 spin_lock(&ubd_lock); 815 816 if(ubd_gendisk[n] == NULL) 817 goto out; 818 819 del_gendisk(ubd_gendisk[n]); 820 put_disk(ubd_gendisk[n]); 821 ubd_gendisk[n] = NULL; 822 823 if(fake_gendisk[n] != NULL){ 824 del_gendisk(fake_gendisk[n]); 825 put_disk(fake_gendisk[n]); 826 fake_gendisk[n] = NULL; 827 } 828 829 platform_device_unregister(&dev->pdev); 830 *dev = ((struct ubd) DEFAULT_UBD); 831 err = 0; 832 out: 833 spin_unlock(&ubd_lock); 834 return(err); 835 } 836 837 static struct mc_device ubd_mc = { 838 .name = "ubd", 839 .config = ubd_config, 840 .get_config = ubd_get_config, 841 .remove = ubd_remove, 842 }; 843 844 static int ubd_mc_init(void) 845 { 846 mconsole_register_dev(&ubd_mc); 847 return 0; 848 } 849 850 __initcall(ubd_mc_init); 851 852 static struct device_driver ubd_driver = { 853 .name = DRIVER_NAME, 854 .bus = &platform_bus_type, 855 }; 856 857 int ubd_init(void) 858 { 859 int i; 860 861 devfs_mk_dir("ubd"); 862 if (register_blkdev(MAJOR_NR, "ubd")) 863 return -1; 864 865 ubd_queue = blk_init_queue(do_ubd_request, &ubd_io_lock); 866 if (!ubd_queue) { 867 unregister_blkdev(MAJOR_NR, "ubd"); 868 return -1; 869 } 870 871 if (fake_major != MAJOR_NR) { 872 char name[sizeof("ubd_nnn\0")]; 873 874 snprintf(name, sizeof(name), "ubd_%d", fake_major); 875 devfs_mk_dir(name); 876 if (register_blkdev(fake_major, "ubd")) 877 return -1; 878 } 879 driver_register(&ubd_driver); 880 for (i = 0; i < MAX_DEV; i++) 881 ubd_add(i); 882 return 0; 883 } 884 885 late_initcall(ubd_init); 886 887 int ubd_driver_init(void){ 888 unsigned long stack; 889 int err; 890 891 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 892 if(global_openflags.s){ 893 printk(KERN_INFO "ubd: Synchronous mode\n"); 894 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 895 * enough. So use anyway the io thread. */ 896 } 897 stack = alloc_stack(0, 0); 898 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), 899 &thread_fd); 900 if(io_pid < 0){ 901 printk(KERN_ERR 902 "ubd : Failed to start I/O thread (errno = %d) - " 903 "falling back to synchronous I/O\n", -io_pid); 904 io_pid = -1; 905 return(0); 906 } 907 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 908 SA_INTERRUPT, "ubd", ubd_dev); 909 if(err != 0) 910 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 911 return(err); 912 } 913 914 device_initcall(ubd_driver_init); 915 916 static int ubd_open(struct inode *inode, struct file *filp) 917 { 918 struct gendisk *disk = inode->i_bdev->bd_disk; 919 struct ubd *dev = disk->private_data; 920 int err = 0; 921 922 if(dev->count == 0){ 923 err = ubd_open_dev(dev); 924 if(err){ 925 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 926 disk->disk_name, dev->file, -err); 927 goto out; 928 } 929 } 930 dev->count++; 931 set_disk_ro(disk, !dev->openflags.w); 932 933 /* This should no more be needed. And it didn't work anyway to exclude 934 * read-write remounting of filesystems.*/ 935 /*if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){ 936 if(--dev->count == 0) ubd_close(dev); 937 err = -EROFS; 938 }*/ 939 out: 940 return(err); 941 } 942 943 static int ubd_release(struct inode * inode, struct file * file) 944 { 945 struct gendisk *disk = inode->i_bdev->bd_disk; 946 struct ubd *dev = disk->private_data; 947 948 if(--dev->count == 0) 949 ubd_close(dev); 950 return(0); 951 } 952 953 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 954 __u64 *cow_offset, unsigned long *bitmap, 955 __u64 bitmap_offset, unsigned long *bitmap_words, 956 __u64 bitmap_len) 957 { 958 __u64 sector = io_offset >> 9; 959 int i, update_bitmap = 0; 960 961 for(i = 0; i < length >> 9; i++){ 962 if(cow_mask != NULL) 963 ubd_set_bit(i, (unsigned char *) cow_mask); 964 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 965 continue; 966 967 update_bitmap = 1; 968 ubd_set_bit(sector + i, (unsigned char *) bitmap); 969 } 970 971 if(!update_bitmap) 972 return; 973 974 *cow_offset = sector / (sizeof(unsigned long) * 8); 975 976 /* This takes care of the case where we're exactly at the end of the 977 * device, and *cow_offset + 1 is off the end. So, just back it up 978 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 979 * for the original diagnosis. 980 */ 981 if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) / 982 sizeof(unsigned long) - 1)) 983 (*cow_offset)--; 984 985 bitmap_words[0] = bitmap[*cow_offset]; 986 bitmap_words[1] = bitmap[*cow_offset + 1]; 987 988 *cow_offset *= sizeof(unsigned long); 989 *cow_offset += bitmap_offset; 990 } 991 992 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, 993 __u64 bitmap_offset, __u64 bitmap_len) 994 { 995 __u64 sector = req->offset >> 9; 996 int i; 997 998 if(req->length > (sizeof(req->sector_mask) * 8) << 9) 999 panic("Operation too long"); 1000 1001 if(req->op == UBD_READ) { 1002 for(i = 0; i < req->length >> 9; i++){ 1003 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1004 ubd_set_bit(i, (unsigned char *) 1005 &req->sector_mask); 1006 } 1007 } 1008 else cowify_bitmap(req->offset, req->length, &req->sector_mask, 1009 &req->cow_offset, bitmap, bitmap_offset, 1010 req->bitmap_words, bitmap_len); 1011 } 1012 1013 static int mmap_fd(struct request *req, struct ubd *dev, __u64 offset) 1014 { 1015 __u64 sector; 1016 unsigned char *bitmap; 1017 int bit, i; 1018 1019 /* mmap must have been requested on the command line */ 1020 if(!ubd_do_mmap) 1021 return(-1); 1022 1023 /* The buffer must be page aligned */ 1024 if(((unsigned long) req->buffer % UBD_MMAP_BLOCK_SIZE) != 0) 1025 return(-1); 1026 1027 /* The request must be a page long */ 1028 if((req->current_nr_sectors << 9) != PAGE_SIZE) 1029 return(-1); 1030 1031 if(dev->cow.file == NULL) 1032 return(dev->fd); 1033 1034 sector = offset >> 9; 1035 bitmap = (unsigned char *) dev->cow.bitmap; 1036 bit = ubd_test_bit(sector, bitmap); 1037 1038 for(i = 1; i < req->current_nr_sectors; i++){ 1039 if(ubd_test_bit(sector + i, bitmap) != bit) 1040 return(-1); 1041 } 1042 1043 if(bit || (rq_data_dir(req) == WRITE)) 1044 offset += dev->cow.data_offset; 1045 1046 /* The data on disk must be page aligned */ 1047 if((offset % UBD_MMAP_BLOCK_SIZE) != 0) 1048 return(-1); 1049 1050 return(bit ? dev->fd : dev->cow.fd); 1051 } 1052 1053 static int prepare_mmap_request(struct ubd *dev, int fd, __u64 offset, 1054 struct request *req, 1055 struct io_thread_req *io_req) 1056 { 1057 int err; 1058 1059 if(rq_data_dir(req) == WRITE){ 1060 /* Writes are almost no-ops since the new data is already in the 1061 * host page cache 1062 */ 1063 dev->map_writes++; 1064 if(dev->cow.file != NULL) 1065 cowify_bitmap(io_req->offset, io_req->length, 1066 &io_req->sector_mask, &io_req->cow_offset, 1067 dev->cow.bitmap, dev->cow.bitmap_offset, 1068 io_req->bitmap_words, 1069 dev->cow.bitmap_len); 1070 } 1071 else { 1072 int w; 1073 1074 if((dev->cow.file != NULL) && (fd == dev->cow.fd)) 1075 w = 0; 1076 else w = dev->openflags.w; 1077 1078 if((dev->cow.file != NULL) && (fd == dev->fd)) 1079 offset += dev->cow.data_offset; 1080 1081 err = physmem_subst_mapping(req->buffer, fd, offset, w); 1082 if(err){ 1083 printk("physmem_subst_mapping failed, err = %d\n", 1084 -err); 1085 return(1); 1086 } 1087 dev->map_reads++; 1088 } 1089 io_req->op = UBD_MMAP; 1090 io_req->buffer = req->buffer; 1091 return(0); 1092 } 1093 1094 /* Called with ubd_io_lock held */ 1095 static int prepare_request(struct request *req, struct io_thread_req *io_req) 1096 { 1097 struct gendisk *disk = req->rq_disk; 1098 struct ubd *dev = disk->private_data; 1099 __u64 offset; 1100 int len, fd; 1101 1102 if(req->rq_status == RQ_INACTIVE) return(1); 1103 1104 /* This should be impossible now */ 1105 if((rq_data_dir(req) == WRITE) && !dev->openflags.w){ 1106 printk("Write attempted on readonly ubd device %s\n", 1107 disk->disk_name); 1108 end_request(req, 0); 1109 return(1); 1110 } 1111 1112 offset = ((__u64) req->sector) << 9; 1113 len = req->current_nr_sectors << 9; 1114 1115 io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd; 1116 io_req->fds[1] = dev->fd; 1117 io_req->map_fd = -1; 1118 io_req->cow_offset = -1; 1119 io_req->offset = offset; 1120 io_req->length = len; 1121 io_req->error = 0; 1122 io_req->sector_mask = 0; 1123 1124 fd = mmap_fd(req, dev, io_req->offset); 1125 if(fd > 0){ 1126 /* If mmapping is otherwise OK, but the first access to the 1127 * page is a write, then it's not mapped in yet. So we have 1128 * to write the data to disk first, then we can map the disk 1129 * page in and continue normally from there. 1130 */ 1131 if((rq_data_dir(req) == WRITE) && !is_remapped(req->buffer)){ 1132 io_req->map_fd = dev->fd; 1133 io_req->map_offset = io_req->offset + 1134 dev->cow.data_offset; 1135 dev->write_maps++; 1136 } 1137 else return(prepare_mmap_request(dev, fd, io_req->offset, req, 1138 io_req)); 1139 } 1140 1141 if(rq_data_dir(req) == READ) 1142 dev->nomap_reads++; 1143 else dev->nomap_writes++; 1144 1145 io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; 1146 io_req->offsets[0] = 0; 1147 io_req->offsets[1] = dev->cow.data_offset; 1148 io_req->buffer = req->buffer; 1149 io_req->sectorsize = 1 << 9; 1150 1151 if(dev->cow.file != NULL) 1152 cowify_req(io_req, dev->cow.bitmap, dev->cow.bitmap_offset, 1153 dev->cow.bitmap_len); 1154 1155 return(0); 1156 } 1157 1158 /* Called with ubd_io_lock held */ 1159 static void do_ubd_request(request_queue_t *q) 1160 { 1161 struct io_thread_req io_req; 1162 struct request *req; 1163 int err, n; 1164 1165 if(thread_fd == -1){ 1166 while((req = elv_next_request(q)) != NULL){ 1167 err = prepare_request(req, &io_req); 1168 if(!err){ 1169 do_io(&io_req); 1170 __ubd_finish(req, io_req.error); 1171 } 1172 } 1173 } 1174 else { 1175 if(do_ubd || (req = elv_next_request(q)) == NULL) 1176 return; 1177 err = prepare_request(req, &io_req); 1178 if(!err){ 1179 do_ubd = ubd_handler; 1180 n = os_write_file(thread_fd, (char *) &io_req, 1181 sizeof(io_req)); 1182 if(n != sizeof(io_req)) 1183 printk("write to io thread failed, " 1184 "errno = %d\n", -n); 1185 } 1186 } 1187 } 1188 1189 static int ubd_ioctl(struct inode * inode, struct file * file, 1190 unsigned int cmd, unsigned long arg) 1191 { 1192 struct hd_geometry __user *loc = (struct hd_geometry __user *) arg; 1193 struct ubd *dev = inode->i_bdev->bd_disk->private_data; 1194 struct hd_driveid ubd_id = { 1195 .cyls = 0, 1196 .heads = 128, 1197 .sectors = 32, 1198 }; 1199 1200 switch (cmd) { 1201 struct hd_geometry g; 1202 struct cdrom_volctrl volume; 1203 case HDIO_GETGEO: 1204 if(!loc) return(-EINVAL); 1205 g.heads = 128; 1206 g.sectors = 32; 1207 g.cylinders = dev->size / (128 * 32 * 512); 1208 g.start = get_start_sect(inode->i_bdev); 1209 return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0); 1210 1211 case HDIO_GET_IDENTITY: 1212 ubd_id.cyls = dev->size / (128 * 32 * 512); 1213 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1214 sizeof(ubd_id))) 1215 return(-EFAULT); 1216 return(0); 1217 1218 case CDROMVOLREAD: 1219 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1220 return(-EFAULT); 1221 volume.channel0 = 255; 1222 volume.channel1 = 255; 1223 volume.channel2 = 255; 1224 volume.channel3 = 255; 1225 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1226 return(-EFAULT); 1227 return(0); 1228 } 1229 return(-EINVAL); 1230 } 1231 1232 static int ubd_check_remapped(int fd, unsigned long address, int is_write, 1233 __u64 offset) 1234 { 1235 __u64 bitmap_offset; 1236 unsigned long new_bitmap[2]; 1237 int i, err, n; 1238 1239 /* If it's not a write access, we can't do anything about it */ 1240 if(!is_write) 1241 return(0); 1242 1243 /* We have a write */ 1244 for(i = 0; i < sizeof(ubd_dev) / sizeof(ubd_dev[0]); i++){ 1245 struct ubd *dev = &ubd_dev[i]; 1246 1247 if((dev->fd != fd) && (dev->cow.fd != fd)) 1248 continue; 1249 1250 /* It's a write to a ubd device */ 1251 1252 /* This should be impossible now */ 1253 if(!dev->openflags.w){ 1254 /* It's a write access on a read-only device - probably 1255 * shouldn't happen. If the kernel is trying to change 1256 * something with no intention of writing it back out, 1257 * then this message will clue us in that this needs 1258 * fixing 1259 */ 1260 printk("Write access to mapped page from readonly ubd " 1261 "device %d\n", i); 1262 return(0); 1263 } 1264 1265 /* It's a write to a writeable ubd device - it must be COWed 1266 * because, otherwise, the page would have been mapped in 1267 * writeable 1268 */ 1269 1270 if(!dev->cow.file) 1271 panic("Write fault on writeable non-COW ubd device %d", 1272 i); 1273 1274 /* It should also be an access to the backing file since the 1275 * COW pages should be mapped in read-write 1276 */ 1277 1278 if(fd == dev->fd) 1279 panic("Write fault on a backing page of ubd " 1280 "device %d\n", i); 1281 1282 /* So, we do the write, copying the backing data to the COW 1283 * file... 1284 */ 1285 1286 err = os_seek_file(dev->fd, offset + dev->cow.data_offset); 1287 if(err < 0) 1288 panic("Couldn't seek to %lld in COW file of ubd " 1289 "device %d, err = %d", 1290 offset + dev->cow.data_offset, i, -err); 1291 1292 n = os_write_file(dev->fd, (void *) address, PAGE_SIZE); 1293 if(n != PAGE_SIZE) 1294 panic("Couldn't copy data to COW file of ubd " 1295 "device %d, err = %d", i, -n); 1296 1297 /* ... updating the COW bitmap... */ 1298 1299 cowify_bitmap(offset, PAGE_SIZE, NULL, &bitmap_offset, 1300 dev->cow.bitmap, dev->cow.bitmap_offset, 1301 new_bitmap, dev->cow.bitmap_len); 1302 1303 err = os_seek_file(dev->fd, bitmap_offset); 1304 if(err < 0) 1305 panic("Couldn't seek to %lld in COW file of ubd " 1306 "device %d, err = %d", bitmap_offset, i, -err); 1307 1308 n = os_write_file(dev->fd, new_bitmap, sizeof(new_bitmap)); 1309 if(n != sizeof(new_bitmap)) 1310 panic("Couldn't update bitmap of ubd device %d, " 1311 "err = %d", i, -n); 1312 1313 /* Maybe we can map the COW page in, and maybe we can't. If 1314 * it is a pre-V3 COW file, we can't, since the alignment will 1315 * be wrong. If it is a V3 or later COW file which has been 1316 * moved to a system with a larger page size, then maybe we 1317 * can't, depending on the exact location of the page. 1318 */ 1319 1320 offset += dev->cow.data_offset; 1321 1322 /* Remove the remapping, putting the original anonymous page 1323 * back. If the COW file can be mapped in, that is done. 1324 * Otherwise, the COW page is read in. 1325 */ 1326 1327 if(!physmem_remove_mapping((void *) address)) 1328 panic("Address 0x%lx not remapped by ubd device %d", 1329 address, i); 1330 if((offset % UBD_MMAP_BLOCK_SIZE) == 0) 1331 physmem_subst_mapping((void *) address, dev->fd, 1332 offset, 1); 1333 else { 1334 err = os_seek_file(dev->fd, offset); 1335 if(err < 0) 1336 panic("Couldn't seek to %lld in COW file of " 1337 "ubd device %d, err = %d", offset, i, 1338 -err); 1339 1340 n = os_read_file(dev->fd, (void *) address, PAGE_SIZE); 1341 if(n != PAGE_SIZE) 1342 panic("Failed to read page from offset %llx of " 1343 "COW file of ubd device %d, err = %d", 1344 offset, i, -n); 1345 } 1346 1347 return(1); 1348 } 1349 1350 /* It's not a write on a ubd device */ 1351 return(0); 1352 } 1353 1354 static struct remapper ubd_remapper = { 1355 .list = LIST_HEAD_INIT(ubd_remapper.list), 1356 .proc = ubd_check_remapped, 1357 }; 1358 1359 static int ubd_remapper_setup(void) 1360 { 1361 if(ubd_do_mmap) 1362 register_remapper(&ubd_remapper); 1363 1364 return(0); 1365 } 1366 1367 __initcall(ubd_remapper_setup); 1368 1369 static int same_backing_files(char *from_cmdline, char *from_cow, char *cow) 1370 { 1371 struct uml_stat buf1, buf2; 1372 int err; 1373 1374 if(from_cmdline == NULL) return(1); 1375 if(!strcmp(from_cmdline, from_cow)) return(1); 1376 1377 err = os_stat_file(from_cmdline, &buf1); 1378 if(err < 0){ 1379 printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err); 1380 return(1); 1381 } 1382 err = os_stat_file(from_cow, &buf2); 1383 if(err < 0){ 1384 printk("Couldn't stat '%s', err = %d\n", from_cow, -err); 1385 return(1); 1386 } 1387 if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 1388 return(1); 1389 1390 printk("Backing file mismatch - \"%s\" requested,\n" 1391 "\"%s\" specified in COW header of \"%s\"\n", 1392 from_cmdline, from_cow, cow); 1393 return(0); 1394 } 1395 1396 static int backing_file_mismatch(char *file, __u64 size, time_t mtime) 1397 { 1398 unsigned long modtime; 1399 long long actual; 1400 int err; 1401 1402 err = os_file_modtime(file, &modtime); 1403 if(err < 0){ 1404 printk("Failed to get modification time of backing file " 1405 "\"%s\", err = %d\n", file, -err); 1406 return(err); 1407 } 1408 1409 err = os_file_size(file, &actual); 1410 if(err < 0){ 1411 printk("Failed to get size of backing file \"%s\", " 1412 "err = %d\n", file, -err); 1413 return(err); 1414 } 1415 1416 if(actual != size){ 1417 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 1418 * the typecast.*/ 1419 printk("Size mismatch (%llu vs %llu) of COW header vs backing " 1420 "file\n", (unsigned long long) size, actual); 1421 return(-EINVAL); 1422 } 1423 if(modtime != mtime){ 1424 printk("mtime mismatch (%ld vs %ld) of COW header vs backing " 1425 "file\n", mtime, modtime); 1426 return(-EINVAL); 1427 } 1428 return(0); 1429 } 1430 1431 int read_cow_bitmap(int fd, void *buf, int offset, int len) 1432 { 1433 int err; 1434 1435 err = os_seek_file(fd, offset); 1436 if(err < 0) 1437 return(err); 1438 1439 err = os_read_file(fd, buf, len); 1440 if(err < 0) 1441 return(err); 1442 1443 return(0); 1444 } 1445 1446 int open_ubd_file(char *file, struct openflags *openflags, 1447 char **backing_file_out, int *bitmap_offset_out, 1448 unsigned long *bitmap_len_out, int *data_offset_out, 1449 int *create_cow_out) 1450 { 1451 time_t mtime; 1452 unsigned long long size; 1453 __u32 version, align; 1454 char *backing_file; 1455 int fd, err, sectorsize, same, mode = 0644; 1456 1457 fd = os_open_file(file, *openflags, mode); 1458 if(fd < 0){ 1459 if((fd == -ENOENT) && (create_cow_out != NULL)) 1460 *create_cow_out = 1; 1461 if(!openflags->w || 1462 ((fd != -EROFS) && (fd != -EACCES))) return(fd); 1463 openflags->w = 0; 1464 fd = os_open_file(file, *openflags, mode); 1465 if(fd < 0) 1466 return(fd); 1467 } 1468 1469 err = os_lock_file(fd, openflags->w); 1470 if(err < 0){ 1471 printk("Failed to lock '%s', err = %d\n", file, -err); 1472 goto out_close; 1473 } 1474 1475 if(backing_file_out == NULL) return(fd); 1476 1477 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 1478 &size, §orsize, &align, bitmap_offset_out); 1479 if(err && (*backing_file_out != NULL)){ 1480 printk("Failed to read COW header from COW file \"%s\", " 1481 "errno = %d\n", file, -err); 1482 goto out_close; 1483 } 1484 if(err) return(fd); 1485 1486 if(backing_file_out == NULL) return(fd); 1487 1488 same = same_backing_files(*backing_file_out, backing_file, file); 1489 1490 if(!same && !backing_file_mismatch(*backing_file_out, size, mtime)){ 1491 printk("Switching backing file to '%s'\n", *backing_file_out); 1492 err = write_cow_header(file, fd, *backing_file_out, 1493 sectorsize, align, &size); 1494 if(err){ 1495 printk("Switch failed, errno = %d\n", -err); 1496 return(err); 1497 } 1498 } 1499 else { 1500 *backing_file_out = backing_file; 1501 err = backing_file_mismatch(*backing_file_out, size, mtime); 1502 if(err) goto out_close; 1503 } 1504 1505 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 1506 bitmap_len_out, data_offset_out); 1507 1508 return(fd); 1509 out_close: 1510 os_close_file(fd); 1511 return(err); 1512 } 1513 1514 int create_cow_file(char *cow_file, char *backing_file, struct openflags flags, 1515 int sectorsize, int alignment, int *bitmap_offset_out, 1516 unsigned long *bitmap_len_out, int *data_offset_out) 1517 { 1518 int err, fd; 1519 1520 flags.c = 1; 1521 fd = open_ubd_file(cow_file, &flags, NULL, NULL, NULL, NULL, NULL); 1522 if(fd < 0){ 1523 err = fd; 1524 printk("Open of COW file '%s' failed, errno = %d\n", cow_file, 1525 -err); 1526 goto out; 1527 } 1528 1529 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 1530 bitmap_offset_out, bitmap_len_out, 1531 data_offset_out); 1532 if(!err) 1533 return(fd); 1534 os_close_file(fd); 1535 out: 1536 return(err); 1537 } 1538 1539 static int update_bitmap(struct io_thread_req *req) 1540 { 1541 int n; 1542 1543 if(req->cow_offset == -1) 1544 return(0); 1545 1546 n = os_seek_file(req->fds[1], req->cow_offset); 1547 if(n < 0){ 1548 printk("do_io - bitmap lseek failed : err = %d\n", -n); 1549 return(1); 1550 } 1551 1552 n = os_write_file(req->fds[1], &req->bitmap_words, 1553 sizeof(req->bitmap_words)); 1554 if(n != sizeof(req->bitmap_words)){ 1555 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, 1556 req->fds[1]); 1557 return(1); 1558 } 1559 1560 return(0); 1561 } 1562 1563 void do_io(struct io_thread_req *req) 1564 { 1565 char *buf; 1566 unsigned long len; 1567 int n, nsectors, start, end, bit; 1568 int err; 1569 __u64 off; 1570 1571 if(req->op == UBD_MMAP){ 1572 /* Touch the page to force the host to do any necessary IO to 1573 * get it into memory 1574 */ 1575 n = *((volatile int *) req->buffer); 1576 req->error = update_bitmap(req); 1577 return; 1578 } 1579 1580 nsectors = req->length / req->sectorsize; 1581 start = 0; 1582 do { 1583 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); 1584 end = start; 1585 while((end < nsectors) && 1586 (ubd_test_bit(end, (unsigned char *) 1587 &req->sector_mask) == bit)) 1588 end++; 1589 1590 off = req->offset + req->offsets[bit] + 1591 start * req->sectorsize; 1592 len = (end - start) * req->sectorsize; 1593 buf = &req->buffer[start * req->sectorsize]; 1594 1595 err = os_seek_file(req->fds[bit], off); 1596 if(err < 0){ 1597 printk("do_io - lseek failed : err = %d\n", -err); 1598 req->error = 1; 1599 return; 1600 } 1601 if(req->op == UBD_READ){ 1602 n = 0; 1603 do { 1604 buf = &buf[n]; 1605 len -= n; 1606 n = os_read_file(req->fds[bit], buf, len); 1607 if (n < 0) { 1608 printk("do_io - read failed, err = %d " 1609 "fd = %d\n", -n, req->fds[bit]); 1610 req->error = 1; 1611 return; 1612 } 1613 } while((n < len) && (n != 0)); 1614 if (n < len) memset(&buf[n], 0, len - n); 1615 } else { 1616 n = os_write_file(req->fds[bit], buf, len); 1617 if(n != len){ 1618 printk("do_io - write failed err = %d " 1619 "fd = %d\n", -n, req->fds[bit]); 1620 req->error = 1; 1621 return; 1622 } 1623 } 1624 1625 start = end; 1626 } while(start < nsectors); 1627 1628 req->error = update_bitmap(req); 1629 } 1630 1631 /* Changed in start_io_thread, which is serialized by being called only 1632 * from ubd_init, which is an initcall. 1633 */ 1634 int kernel_fd = -1; 1635 1636 /* Only changed by the io thread */ 1637 int io_count = 0; 1638 1639 int io_thread(void *arg) 1640 { 1641 struct io_thread_req req; 1642 int n; 1643 1644 ignore_sigwinch_sig(); 1645 while(1){ 1646 n = os_read_file(kernel_fd, &req, sizeof(req)); 1647 if(n != sizeof(req)){ 1648 if(n < 0) 1649 printk("io_thread - read failed, fd = %d, " 1650 "err = %d\n", kernel_fd, -n); 1651 else { 1652 printk("io_thread - short read, fd = %d, " 1653 "length = %d\n", kernel_fd, n); 1654 } 1655 continue; 1656 } 1657 io_count++; 1658 do_io(&req); 1659 n = os_write_file(kernel_fd, &req, sizeof(req)); 1660 if(n != sizeof(req)) 1661 printk("io_thread - write failed, fd = %d, err = %d\n", 1662 kernel_fd, -n); 1663 } 1664 } 1665 1666 /* 1667 * Overrides for Emacs so that we follow Linus's tabbing style. 1668 * Emacs will notice this stuff at the end of the file and automatically 1669 * adjust the settings for this buffer only. This must remain at the end 1670 * of the file. 1671 * --------------------------------------------------------------------------- 1672 * Local variables: 1673 * c-file-style: "linux" 1674 * End: 1675 */ 1676