1 /* 2 * Copyright (C) 2015-2016 Anton Ivanov (aivanov@brocade.com) 3 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) 4 * Licensed under the GPL 5 */ 6 7 /* 2001-09-28...2002-04-17 8 * Partition stuff by James_McMechan@hotmail.com 9 * old style ubd by setting UBD_SHIFT to 0 10 * 2002-09-27...2002-10-18 massive tinkering for 2.5 11 * partitions have changed in 2.5 12 * 2003-01-29 more tinkering for 2.5.59-1 13 * This should now address the sysfs problems and has 14 * the symlink for devfs to allow for booting with 15 * the common /dev/ubd/discX/... names rather than 16 * only /dev/ubdN/discN this version also has lots of 17 * clean ups preparing for ubd-many. 18 * James McMechan 19 */ 20 21 #define UBD_SHIFT 4 22 23 #include <linux/module.h> 24 #include <linux/init.h> 25 #include <linux/blkdev.h> 26 #include <linux/ata.h> 27 #include <linux/hdreg.h> 28 #include <linux/cdrom.h> 29 #include <linux/proc_fs.h> 30 #include <linux/seq_file.h> 31 #include <linux/ctype.h> 32 #include <linux/slab.h> 33 #include <linux/vmalloc.h> 34 #include <linux/platform_device.h> 35 #include <linux/scatterlist.h> 36 #include <asm/tlbflush.h> 37 #include <kern_util.h> 38 #include "mconsole_kern.h" 39 #include <init.h> 40 #include <irq_kern.h> 41 #include "ubd.h" 42 #include <os.h> 43 #include "cow.h" 44 45 enum ubd_req { UBD_READ, UBD_WRITE, UBD_FLUSH }; 46 47 struct io_thread_req { 48 struct request *req; 49 enum ubd_req op; 50 int fds[2]; 51 unsigned long offsets[2]; 52 unsigned long long offset; 53 unsigned long length; 54 char *buffer; 55 int sectorsize; 56 unsigned long sector_mask; 57 unsigned long long cow_offset; 58 unsigned long bitmap_words[2]; 59 int error; 60 }; 61 62 63 static struct io_thread_req * (*irq_req_buffer)[]; 64 static struct io_thread_req *irq_remainder; 65 static int irq_remainder_size; 66 67 static struct io_thread_req * (*io_req_buffer)[]; 68 static struct io_thread_req *io_remainder; 69 static int io_remainder_size; 70 71 72 73 static inline int ubd_test_bit(__u64 bit, unsigned char *data) 74 { 75 __u64 n; 76 int bits, off; 77 78 bits = sizeof(data[0]) * 8; 79 n = bit / bits; 80 off = bit % bits; 81 return (data[n] & (1 << off)) != 0; 82 } 83 84 static inline void ubd_set_bit(__u64 bit, unsigned char *data) 85 { 86 __u64 n; 87 int bits, off; 88 89 bits = sizeof(data[0]) * 8; 90 n = bit / bits; 91 off = bit % bits; 92 data[n] |= (1 << off); 93 } 94 /*End stuff from ubd_user.h*/ 95 96 #define DRIVER_NAME "uml-blkdev" 97 98 static DEFINE_MUTEX(ubd_lock); 99 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */ 100 101 static int ubd_open(struct block_device *bdev, fmode_t mode); 102 static void ubd_release(struct gendisk *disk, fmode_t mode); 103 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 104 unsigned int cmd, unsigned long arg); 105 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); 106 107 #define MAX_DEV (16) 108 109 static const struct block_device_operations ubd_blops = { 110 .owner = THIS_MODULE, 111 .open = ubd_open, 112 .release = ubd_release, 113 .ioctl = ubd_ioctl, 114 .getgeo = ubd_getgeo, 115 }; 116 117 /* Protected by ubd_lock */ 118 static int fake_major = UBD_MAJOR; 119 static struct gendisk *ubd_gendisk[MAX_DEV]; 120 static struct gendisk *fake_gendisk[MAX_DEV]; 121 122 #ifdef CONFIG_BLK_DEV_UBD_SYNC 123 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ 124 .cl = 1 }) 125 #else 126 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ 127 .cl = 1 }) 128 #endif 129 static struct openflags global_openflags = OPEN_FLAGS; 130 131 struct cow { 132 /* backing file name */ 133 char *file; 134 /* backing file fd */ 135 int fd; 136 unsigned long *bitmap; 137 unsigned long bitmap_len; 138 int bitmap_offset; 139 int data_offset; 140 }; 141 142 #define MAX_SG 64 143 144 struct ubd { 145 struct list_head restart; 146 /* name (and fd, below) of the file opened for writing, either the 147 * backing or the cow file. */ 148 char *file; 149 int count; 150 int fd; 151 __u64 size; 152 struct openflags boot_openflags; 153 struct openflags openflags; 154 unsigned shared:1; 155 unsigned no_cow:1; 156 struct cow cow; 157 struct platform_device pdev; 158 struct request_queue *queue; 159 spinlock_t lock; 160 struct scatterlist sg[MAX_SG]; 161 struct request *request; 162 int start_sg, end_sg; 163 sector_t rq_pos; 164 }; 165 166 #define DEFAULT_COW { \ 167 .file = NULL, \ 168 .fd = -1, \ 169 .bitmap = NULL, \ 170 .bitmap_offset = 0, \ 171 .data_offset = 0, \ 172 } 173 174 #define DEFAULT_UBD { \ 175 .file = NULL, \ 176 .count = 0, \ 177 .fd = -1, \ 178 .size = -1, \ 179 .boot_openflags = OPEN_FLAGS, \ 180 .openflags = OPEN_FLAGS, \ 181 .no_cow = 0, \ 182 .shared = 0, \ 183 .cow = DEFAULT_COW, \ 184 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \ 185 .request = NULL, \ 186 .start_sg = 0, \ 187 .end_sg = 0, \ 188 .rq_pos = 0, \ 189 } 190 191 /* Protected by ubd_lock */ 192 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD }; 193 194 /* Only changed by fake_ide_setup which is a setup */ 195 static int fake_ide = 0; 196 static struct proc_dir_entry *proc_ide_root = NULL; 197 static struct proc_dir_entry *proc_ide = NULL; 198 199 static void make_proc_ide(void) 200 { 201 proc_ide_root = proc_mkdir("ide", NULL); 202 proc_ide = proc_mkdir("ide0", proc_ide_root); 203 } 204 205 static int fake_ide_media_proc_show(struct seq_file *m, void *v) 206 { 207 seq_puts(m, "disk\n"); 208 return 0; 209 } 210 211 static int fake_ide_media_proc_open(struct inode *inode, struct file *file) 212 { 213 return single_open(file, fake_ide_media_proc_show, NULL); 214 } 215 216 static const struct file_operations fake_ide_media_proc_fops = { 217 .owner = THIS_MODULE, 218 .open = fake_ide_media_proc_open, 219 .read = seq_read, 220 .llseek = seq_lseek, 221 .release = single_release, 222 }; 223 224 static void make_ide_entries(const char *dev_name) 225 { 226 struct proc_dir_entry *dir, *ent; 227 char name[64]; 228 229 if(proc_ide_root == NULL) make_proc_ide(); 230 231 dir = proc_mkdir(dev_name, proc_ide); 232 if(!dir) return; 233 234 ent = proc_create("media", S_IRUGO, dir, &fake_ide_media_proc_fops); 235 if(!ent) return; 236 snprintf(name, sizeof(name), "ide0/%s", dev_name); 237 proc_symlink(dev_name, proc_ide_root, name); 238 } 239 240 static int fake_ide_setup(char *str) 241 { 242 fake_ide = 1; 243 return 1; 244 } 245 246 __setup("fake_ide", fake_ide_setup); 247 248 __uml_help(fake_ide_setup, 249 "fake_ide\n" 250 " Create ide0 entries that map onto ubd devices.\n\n" 251 ); 252 253 static int parse_unit(char **ptr) 254 { 255 char *str = *ptr, *end; 256 int n = -1; 257 258 if(isdigit(*str)) { 259 n = simple_strtoul(str, &end, 0); 260 if(end == str) 261 return -1; 262 *ptr = end; 263 } 264 else if (('a' <= *str) && (*str <= 'z')) { 265 n = *str - 'a'; 266 str++; 267 *ptr = str; 268 } 269 return n; 270 } 271 272 /* If *index_out == -1 at exit, the passed option was a general one; 273 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it 274 * should not be freed on exit. 275 */ 276 static int ubd_setup_common(char *str, int *index_out, char **error_out) 277 { 278 struct ubd *ubd_dev; 279 struct openflags flags = global_openflags; 280 char *backing_file; 281 int n, err = 0, i; 282 283 if(index_out) *index_out = -1; 284 n = *str; 285 if(n == '='){ 286 char *end; 287 int major; 288 289 str++; 290 if(!strcmp(str, "sync")){ 291 global_openflags = of_sync(global_openflags); 292 goto out1; 293 } 294 295 err = -EINVAL; 296 major = simple_strtoul(str, &end, 0); 297 if((*end != '\0') || (end == str)){ 298 *error_out = "Didn't parse major number"; 299 goto out1; 300 } 301 302 mutex_lock(&ubd_lock); 303 if (fake_major != UBD_MAJOR) { 304 *error_out = "Can't assign a fake major twice"; 305 goto out1; 306 } 307 308 fake_major = major; 309 310 printk(KERN_INFO "Setting extra ubd major number to %d\n", 311 major); 312 err = 0; 313 out1: 314 mutex_unlock(&ubd_lock); 315 return err; 316 } 317 318 n = parse_unit(&str); 319 if(n < 0){ 320 *error_out = "Couldn't parse device number"; 321 return -EINVAL; 322 } 323 if(n >= MAX_DEV){ 324 *error_out = "Device number out of range"; 325 return 1; 326 } 327 328 err = -EBUSY; 329 mutex_lock(&ubd_lock); 330 331 ubd_dev = &ubd_devs[n]; 332 if(ubd_dev->file != NULL){ 333 *error_out = "Device is already configured"; 334 goto out; 335 } 336 337 if (index_out) 338 *index_out = n; 339 340 err = -EINVAL; 341 for (i = 0; i < sizeof("rscd="); i++) { 342 switch (*str) { 343 case 'r': 344 flags.w = 0; 345 break; 346 case 's': 347 flags.s = 1; 348 break; 349 case 'd': 350 ubd_dev->no_cow = 1; 351 break; 352 case 'c': 353 ubd_dev->shared = 1; 354 break; 355 case '=': 356 str++; 357 goto break_loop; 358 default: 359 *error_out = "Expected '=' or flag letter " 360 "(r, s, c, or d)"; 361 goto out; 362 } 363 str++; 364 } 365 366 if (*str == '=') 367 *error_out = "Too many flags specified"; 368 else 369 *error_out = "Missing '='"; 370 goto out; 371 372 break_loop: 373 backing_file = strchr(str, ','); 374 375 if (backing_file == NULL) 376 backing_file = strchr(str, ':'); 377 378 if(backing_file != NULL){ 379 if(ubd_dev->no_cow){ 380 *error_out = "Can't specify both 'd' and a cow file"; 381 goto out; 382 } 383 else { 384 *backing_file = '\0'; 385 backing_file++; 386 } 387 } 388 err = 0; 389 ubd_dev->file = str; 390 ubd_dev->cow.file = backing_file; 391 ubd_dev->boot_openflags = flags; 392 out: 393 mutex_unlock(&ubd_lock); 394 return err; 395 } 396 397 static int ubd_setup(char *str) 398 { 399 char *error; 400 int err; 401 402 err = ubd_setup_common(str, NULL, &error); 403 if(err) 404 printk(KERN_ERR "Failed to initialize device with \"%s\" : " 405 "%s\n", str, error); 406 return 1; 407 } 408 409 __setup("ubd", ubd_setup); 410 __uml_help(ubd_setup, 411 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n" 412 " This is used to associate a device with a file in the underlying\n" 413 " filesystem. When specifying two filenames, the first one is the\n" 414 " COW name and the second is the backing file name. As separator you can\n" 415 " use either a ':' or a ',': the first one allows writing things like;\n" 416 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" 417 " while with a ',' the shell would not expand the 2nd '~'.\n" 418 " When using only one filename, UML will detect whether to treat it like\n" 419 " a COW file or a backing file. To override this detection, add the 'd'\n" 420 " flag:\n" 421 " ubd0d=BackingFile\n" 422 " Usually, there is a filesystem in the file, but \n" 423 " that's not required. Swap devices containing swap files can be\n" 424 " specified like this. Also, a file which doesn't contain a\n" 425 " filesystem can have its contents read in the virtual \n" 426 " machine by running 'dd' on the device. <n> must be in the range\n" 427 " 0 to 7. Appending an 'r' to the number will cause that device\n" 428 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" 429 " an 's' will cause data to be written to disk on the host immediately.\n" 430 " 'c' will cause the device to be treated as being shared between multiple\n" 431 " UMLs and file locking will be turned off - this is appropriate for a\n" 432 " cluster filesystem and inappropriate at almost all other times.\n\n" 433 ); 434 435 static int udb_setup(char *str) 436 { 437 printk("udb%s specified on command line is almost certainly a ubd -> " 438 "udb TYPO\n", str); 439 return 1; 440 } 441 442 __setup("udb", udb_setup); 443 __uml_help(udb_setup, 444 "udb\n" 445 " This option is here solely to catch ubd -> udb typos, which can be\n" 446 " to impossible to catch visually unless you specifically look for\n" 447 " them. The only result of any option starting with 'udb' is an error\n" 448 " in the boot output.\n\n" 449 ); 450 451 static void do_ubd_request(struct request_queue * q); 452 453 /* Only changed by ubd_init, which is an initcall. */ 454 static int thread_fd = -1; 455 static LIST_HEAD(restart); 456 457 /* Function to read several request pointers at a time 458 * handling fractional reads if (and as) needed 459 */ 460 461 static int bulk_req_safe_read( 462 int fd, 463 struct io_thread_req * (*request_buffer)[], 464 struct io_thread_req **remainder, 465 int *remainder_size, 466 int max_recs 467 ) 468 { 469 int n = 0; 470 int res = 0; 471 472 if (*remainder_size > 0) { 473 memmove( 474 (char *) request_buffer, 475 (char *) remainder, *remainder_size 476 ); 477 n = *remainder_size; 478 } 479 480 res = os_read_file( 481 fd, 482 ((char *) request_buffer) + *remainder_size, 483 sizeof(struct io_thread_req *)*max_recs 484 - *remainder_size 485 ); 486 if (res > 0) { 487 n += res; 488 if ((n % sizeof(struct io_thread_req *)) > 0) { 489 /* 490 * Read somehow returned not a multiple of dword 491 * theoretically possible, but never observed in the 492 * wild, so read routine must be able to handle it 493 */ 494 *remainder_size = n % sizeof(struct io_thread_req *); 495 WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); 496 memmove( 497 remainder, 498 ((char *) request_buffer) + 499 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), 500 *remainder_size 501 ); 502 n = n - *remainder_size; 503 } 504 } else { 505 n = res; 506 } 507 return n; 508 } 509 510 /* Called without dev->lock held, and only in interrupt context. */ 511 static void ubd_handler(void) 512 { 513 struct ubd *ubd; 514 struct list_head *list, *next_ele; 515 unsigned long flags; 516 int n; 517 int count; 518 519 while(1){ 520 n = bulk_req_safe_read( 521 thread_fd, 522 irq_req_buffer, 523 &irq_remainder, 524 &irq_remainder_size, 525 UBD_REQ_BUFFER_SIZE 526 ); 527 if (n < 0) { 528 if(n == -EAGAIN) 529 break; 530 printk(KERN_ERR "spurious interrupt in ubd_handler, " 531 "err = %d\n", -n); 532 return; 533 } 534 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 535 blk_end_request( 536 (*irq_req_buffer)[count]->req, 537 BLK_STS_OK, 538 (*irq_req_buffer)[count]->length 539 ); 540 kfree((*irq_req_buffer)[count]); 541 } 542 } 543 reactivate_fd(thread_fd, UBD_IRQ); 544 545 list_for_each_safe(list, next_ele, &restart){ 546 ubd = container_of(list, struct ubd, restart); 547 list_del_init(&ubd->restart); 548 spin_lock_irqsave(&ubd->lock, flags); 549 do_ubd_request(ubd->queue); 550 spin_unlock_irqrestore(&ubd->lock, flags); 551 } 552 } 553 554 static irqreturn_t ubd_intr(int irq, void *dev) 555 { 556 ubd_handler(); 557 return IRQ_HANDLED; 558 } 559 560 /* Only changed by ubd_init, which is an initcall. */ 561 static int io_pid = -1; 562 563 static void kill_io_thread(void) 564 { 565 if(io_pid != -1) 566 os_kill_process(io_pid, 1); 567 } 568 569 __uml_exitcall(kill_io_thread); 570 571 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) 572 { 573 char *file; 574 int fd; 575 int err; 576 577 __u32 version; 578 __u32 align; 579 char *backing_file; 580 time_t mtime; 581 unsigned long long size; 582 int sector_size; 583 int bitmap_offset; 584 585 if (ubd_dev->file && ubd_dev->cow.file) { 586 file = ubd_dev->cow.file; 587 588 goto out; 589 } 590 591 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); 592 if (fd < 0) 593 return fd; 594 595 err = read_cow_header(file_reader, &fd, &version, &backing_file, \ 596 &mtime, &size, §or_size, &align, &bitmap_offset); 597 os_close_file(fd); 598 599 if(err == -EINVAL) 600 file = ubd_dev->file; 601 else 602 file = backing_file; 603 604 out: 605 return os_file_size(file, size_out); 606 } 607 608 static int read_cow_bitmap(int fd, void *buf, int offset, int len) 609 { 610 int err; 611 612 err = os_pread_file(fd, buf, len, offset); 613 if (err < 0) 614 return err; 615 616 return 0; 617 } 618 619 static int backing_file_mismatch(char *file, __u64 size, time_t mtime) 620 { 621 unsigned long modtime; 622 unsigned long long actual; 623 int err; 624 625 err = os_file_modtime(file, &modtime); 626 if (err < 0) { 627 printk(KERN_ERR "Failed to get modification time of backing " 628 "file \"%s\", err = %d\n", file, -err); 629 return err; 630 } 631 632 err = os_file_size(file, &actual); 633 if (err < 0) { 634 printk(KERN_ERR "Failed to get size of backing file \"%s\", " 635 "err = %d\n", file, -err); 636 return err; 637 } 638 639 if (actual != size) { 640 /*__u64 can be a long on AMD64 and with %lu GCC complains; so 641 * the typecast.*/ 642 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " 643 "vs backing file\n", (unsigned long long) size, actual); 644 return -EINVAL; 645 } 646 if (modtime != mtime) { 647 printk(KERN_ERR "mtime mismatch (%ld vs %ld) of COW header vs " 648 "backing file\n", mtime, modtime); 649 return -EINVAL; 650 } 651 return 0; 652 } 653 654 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) 655 { 656 struct uml_stat buf1, buf2; 657 int err; 658 659 if (from_cmdline == NULL) 660 return 0; 661 if (!strcmp(from_cmdline, from_cow)) 662 return 0; 663 664 err = os_stat_file(from_cmdline, &buf1); 665 if (err < 0) { 666 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, 667 -err); 668 return 0; 669 } 670 err = os_stat_file(from_cow, &buf2); 671 if (err < 0) { 672 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow, 673 -err); 674 return 1; 675 } 676 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 677 return 0; 678 679 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, " 680 "\"%s\" specified in COW header of \"%s\"\n", 681 from_cmdline, from_cow, cow); 682 return 1; 683 } 684 685 static int open_ubd_file(char *file, struct openflags *openflags, int shared, 686 char **backing_file_out, int *bitmap_offset_out, 687 unsigned long *bitmap_len_out, int *data_offset_out, 688 int *create_cow_out) 689 { 690 time_t mtime; 691 unsigned long long size; 692 __u32 version, align; 693 char *backing_file; 694 int fd, err, sectorsize, asked_switch, mode = 0644; 695 696 fd = os_open_file(file, *openflags, mode); 697 if (fd < 0) { 698 if ((fd == -ENOENT) && (create_cow_out != NULL)) 699 *create_cow_out = 1; 700 if (!openflags->w || 701 ((fd != -EROFS) && (fd != -EACCES))) 702 return fd; 703 openflags->w = 0; 704 fd = os_open_file(file, *openflags, mode); 705 if (fd < 0) 706 return fd; 707 } 708 709 if (shared) 710 printk(KERN_INFO "Not locking \"%s\" on the host\n", file); 711 else { 712 err = os_lock_file(fd, openflags->w); 713 if (err < 0) { 714 printk(KERN_ERR "Failed to lock '%s', err = %d\n", 715 file, -err); 716 goto out_close; 717 } 718 } 719 720 /* Successful return case! */ 721 if (backing_file_out == NULL) 722 return fd; 723 724 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 725 &size, §orsize, &align, bitmap_offset_out); 726 if (err && (*backing_file_out != NULL)) { 727 printk(KERN_ERR "Failed to read COW header from COW file " 728 "\"%s\", errno = %d\n", file, -err); 729 goto out_close; 730 } 731 if (err) 732 return fd; 733 734 asked_switch = path_requires_switch(*backing_file_out, backing_file, 735 file); 736 737 /* Allow switching only if no mismatch. */ 738 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, 739 mtime)) { 740 printk(KERN_ERR "Switching backing file to '%s'\n", 741 *backing_file_out); 742 err = write_cow_header(file, fd, *backing_file_out, 743 sectorsize, align, &size); 744 if (err) { 745 printk(KERN_ERR "Switch failed, errno = %d\n", -err); 746 goto out_close; 747 } 748 } else { 749 *backing_file_out = backing_file; 750 err = backing_file_mismatch(*backing_file_out, size, mtime); 751 if (err) 752 goto out_close; 753 } 754 755 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, 756 bitmap_len_out, data_offset_out); 757 758 return fd; 759 out_close: 760 os_close_file(fd); 761 return err; 762 } 763 764 static int create_cow_file(char *cow_file, char *backing_file, 765 struct openflags flags, 766 int sectorsize, int alignment, int *bitmap_offset_out, 767 unsigned long *bitmap_len_out, int *data_offset_out) 768 { 769 int err, fd; 770 771 flags.c = 1; 772 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); 773 if (fd < 0) { 774 err = fd; 775 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n", 776 cow_file, -err); 777 goto out; 778 } 779 780 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, 781 bitmap_offset_out, bitmap_len_out, 782 data_offset_out); 783 if (!err) 784 return fd; 785 os_close_file(fd); 786 out: 787 return err; 788 } 789 790 static void ubd_close_dev(struct ubd *ubd_dev) 791 { 792 os_close_file(ubd_dev->fd); 793 if(ubd_dev->cow.file == NULL) 794 return; 795 796 os_close_file(ubd_dev->cow.fd); 797 vfree(ubd_dev->cow.bitmap); 798 ubd_dev->cow.bitmap = NULL; 799 } 800 801 static int ubd_open_dev(struct ubd *ubd_dev) 802 { 803 struct openflags flags; 804 char **back_ptr; 805 int err, create_cow, *create_ptr; 806 int fd; 807 808 ubd_dev->openflags = ubd_dev->boot_openflags; 809 create_cow = 0; 810 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; 811 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; 812 813 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, 814 back_ptr, &ubd_dev->cow.bitmap_offset, 815 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, 816 create_ptr); 817 818 if((fd == -ENOENT) && create_cow){ 819 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, 820 ubd_dev->openflags, 1 << 9, PAGE_SIZE, 821 &ubd_dev->cow.bitmap_offset, 822 &ubd_dev->cow.bitmap_len, 823 &ubd_dev->cow.data_offset); 824 if(fd >= 0){ 825 printk(KERN_INFO "Creating \"%s\" as COW file for " 826 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); 827 } 828 } 829 830 if(fd < 0){ 831 printk("Failed to open '%s', errno = %d\n", ubd_dev->file, 832 -fd); 833 return fd; 834 } 835 ubd_dev->fd = fd; 836 837 if(ubd_dev->cow.file != NULL){ 838 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long)); 839 840 err = -ENOMEM; 841 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len); 842 if(ubd_dev->cow.bitmap == NULL){ 843 printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); 844 goto error; 845 } 846 flush_tlb_kernel_vm(); 847 848 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, 849 ubd_dev->cow.bitmap_offset, 850 ubd_dev->cow.bitmap_len); 851 if(err < 0) 852 goto error; 853 854 flags = ubd_dev->openflags; 855 flags.w = 0; 856 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, 857 NULL, NULL, NULL, NULL); 858 if(err < 0) goto error; 859 ubd_dev->cow.fd = err; 860 } 861 return 0; 862 error: 863 os_close_file(ubd_dev->fd); 864 return err; 865 } 866 867 static void ubd_device_release(struct device *dev) 868 { 869 struct ubd *ubd_dev = dev_get_drvdata(dev); 870 871 blk_cleanup_queue(ubd_dev->queue); 872 *ubd_dev = ((struct ubd) DEFAULT_UBD); 873 } 874 875 static int ubd_disk_register(int major, u64 size, int unit, 876 struct gendisk **disk_out) 877 { 878 struct device *parent = NULL; 879 struct gendisk *disk; 880 881 disk = alloc_disk(1 << UBD_SHIFT); 882 if(disk == NULL) 883 return -ENOMEM; 884 885 disk->major = major; 886 disk->first_minor = unit << UBD_SHIFT; 887 disk->fops = &ubd_blops; 888 set_capacity(disk, size / 512); 889 if (major == UBD_MAJOR) 890 sprintf(disk->disk_name, "ubd%c", 'a' + unit); 891 else 892 sprintf(disk->disk_name, "ubd_fake%d", unit); 893 894 /* sysfs register (not for ide fake devices) */ 895 if (major == UBD_MAJOR) { 896 ubd_devs[unit].pdev.id = unit; 897 ubd_devs[unit].pdev.name = DRIVER_NAME; 898 ubd_devs[unit].pdev.dev.release = ubd_device_release; 899 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]); 900 platform_device_register(&ubd_devs[unit].pdev); 901 parent = &ubd_devs[unit].pdev.dev; 902 } 903 904 disk->private_data = &ubd_devs[unit]; 905 disk->queue = ubd_devs[unit].queue; 906 device_add_disk(parent, disk); 907 908 *disk_out = disk; 909 return 0; 910 } 911 912 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9)) 913 914 static int ubd_add(int n, char **error_out) 915 { 916 struct ubd *ubd_dev = &ubd_devs[n]; 917 int err = 0; 918 919 if(ubd_dev->file == NULL) 920 goto out; 921 922 err = ubd_file_size(ubd_dev, &ubd_dev->size); 923 if(err < 0){ 924 *error_out = "Couldn't determine size of device's file"; 925 goto out; 926 } 927 928 ubd_dev->size = ROUND_BLOCK(ubd_dev->size); 929 930 INIT_LIST_HEAD(&ubd_dev->restart); 931 sg_init_table(ubd_dev->sg, MAX_SG); 932 933 err = -ENOMEM; 934 ubd_dev->queue = blk_init_queue(do_ubd_request, &ubd_dev->lock); 935 if (ubd_dev->queue == NULL) { 936 *error_out = "Failed to initialize device queue"; 937 goto out; 938 } 939 ubd_dev->queue->queuedata = ubd_dev; 940 blk_queue_write_cache(ubd_dev->queue, true, false); 941 942 blk_queue_max_segments(ubd_dev->queue, MAX_SG); 943 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]); 944 if(err){ 945 *error_out = "Failed to register device"; 946 goto out_cleanup; 947 } 948 949 if (fake_major != UBD_MAJOR) 950 ubd_disk_register(fake_major, ubd_dev->size, n, 951 &fake_gendisk[n]); 952 953 /* 954 * Perhaps this should also be under the "if (fake_major)" above 955 * using the fake_disk->disk_name 956 */ 957 if (fake_ide) 958 make_ide_entries(ubd_gendisk[n]->disk_name); 959 960 err = 0; 961 out: 962 return err; 963 964 out_cleanup: 965 blk_cleanup_queue(ubd_dev->queue); 966 goto out; 967 } 968 969 static int ubd_config(char *str, char **error_out) 970 { 971 int n, ret; 972 973 /* This string is possibly broken up and stored, so it's only 974 * freed if ubd_setup_common fails, or if only general options 975 * were set. 976 */ 977 str = kstrdup(str, GFP_KERNEL); 978 if (str == NULL) { 979 *error_out = "Failed to allocate memory"; 980 return -ENOMEM; 981 } 982 983 ret = ubd_setup_common(str, &n, error_out); 984 if (ret) 985 goto err_free; 986 987 if (n == -1) { 988 ret = 0; 989 goto err_free; 990 } 991 992 mutex_lock(&ubd_lock); 993 ret = ubd_add(n, error_out); 994 if (ret) 995 ubd_devs[n].file = NULL; 996 mutex_unlock(&ubd_lock); 997 998 out: 999 return ret; 1000 1001 err_free: 1002 kfree(str); 1003 goto out; 1004 } 1005 1006 static int ubd_get_config(char *name, char *str, int size, char **error_out) 1007 { 1008 struct ubd *ubd_dev; 1009 int n, len = 0; 1010 1011 n = parse_unit(&name); 1012 if((n >= MAX_DEV) || (n < 0)){ 1013 *error_out = "ubd_get_config : device number out of range"; 1014 return -1; 1015 } 1016 1017 ubd_dev = &ubd_devs[n]; 1018 mutex_lock(&ubd_lock); 1019 1020 if(ubd_dev->file == NULL){ 1021 CONFIG_CHUNK(str, size, len, "", 1); 1022 goto out; 1023 } 1024 1025 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); 1026 1027 if(ubd_dev->cow.file != NULL){ 1028 CONFIG_CHUNK(str, size, len, ",", 0); 1029 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); 1030 } 1031 else CONFIG_CHUNK(str, size, len, "", 1); 1032 1033 out: 1034 mutex_unlock(&ubd_lock); 1035 return len; 1036 } 1037 1038 static int ubd_id(char **str, int *start_out, int *end_out) 1039 { 1040 int n; 1041 1042 n = parse_unit(str); 1043 *start_out = 0; 1044 *end_out = MAX_DEV - 1; 1045 return n; 1046 } 1047 1048 static int ubd_remove(int n, char **error_out) 1049 { 1050 struct gendisk *disk = ubd_gendisk[n]; 1051 struct ubd *ubd_dev; 1052 int err = -ENODEV; 1053 1054 mutex_lock(&ubd_lock); 1055 1056 ubd_dev = &ubd_devs[n]; 1057 1058 if(ubd_dev->file == NULL) 1059 goto out; 1060 1061 /* you cannot remove a open disk */ 1062 err = -EBUSY; 1063 if(ubd_dev->count > 0) 1064 goto out; 1065 1066 ubd_gendisk[n] = NULL; 1067 if(disk != NULL){ 1068 del_gendisk(disk); 1069 put_disk(disk); 1070 } 1071 1072 if(fake_gendisk[n] != NULL){ 1073 del_gendisk(fake_gendisk[n]); 1074 put_disk(fake_gendisk[n]); 1075 fake_gendisk[n] = NULL; 1076 } 1077 1078 err = 0; 1079 platform_device_unregister(&ubd_dev->pdev); 1080 out: 1081 mutex_unlock(&ubd_lock); 1082 return err; 1083 } 1084 1085 /* All these are called by mconsole in process context and without 1086 * ubd-specific locks. The structure itself is const except for .list. 1087 */ 1088 static struct mc_device ubd_mc = { 1089 .list = LIST_HEAD_INIT(ubd_mc.list), 1090 .name = "ubd", 1091 .config = ubd_config, 1092 .get_config = ubd_get_config, 1093 .id = ubd_id, 1094 .remove = ubd_remove, 1095 }; 1096 1097 static int __init ubd_mc_init(void) 1098 { 1099 mconsole_register_dev(&ubd_mc); 1100 return 0; 1101 } 1102 1103 __initcall(ubd_mc_init); 1104 1105 static int __init ubd0_init(void) 1106 { 1107 struct ubd *ubd_dev = &ubd_devs[0]; 1108 1109 mutex_lock(&ubd_lock); 1110 if(ubd_dev->file == NULL) 1111 ubd_dev->file = "root_fs"; 1112 mutex_unlock(&ubd_lock); 1113 1114 return 0; 1115 } 1116 1117 __initcall(ubd0_init); 1118 1119 /* Used in ubd_init, which is an initcall */ 1120 static struct platform_driver ubd_driver = { 1121 .driver = { 1122 .name = DRIVER_NAME, 1123 }, 1124 }; 1125 1126 static int __init ubd_init(void) 1127 { 1128 char *error; 1129 int i, err; 1130 1131 if (register_blkdev(UBD_MAJOR, "ubd")) 1132 return -1; 1133 1134 if (fake_major != UBD_MAJOR) { 1135 char name[sizeof("ubd_nnn\0")]; 1136 1137 snprintf(name, sizeof(name), "ubd_%d", fake_major); 1138 if (register_blkdev(fake_major, "ubd")) 1139 return -1; 1140 } 1141 1142 irq_req_buffer = kmalloc( 1143 sizeof(struct io_thread_req *) * UBD_REQ_BUFFER_SIZE, 1144 GFP_KERNEL 1145 ); 1146 irq_remainder = 0; 1147 1148 if (irq_req_buffer == NULL) { 1149 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1150 return -1; 1151 } 1152 io_req_buffer = kmalloc( 1153 sizeof(struct io_thread_req *) * UBD_REQ_BUFFER_SIZE, 1154 GFP_KERNEL 1155 ); 1156 1157 io_remainder = 0; 1158 1159 if (io_req_buffer == NULL) { 1160 printk(KERN_ERR "Failed to initialize ubd buffering\n"); 1161 return -1; 1162 } 1163 platform_driver_register(&ubd_driver); 1164 mutex_lock(&ubd_lock); 1165 for (i = 0; i < MAX_DEV; i++){ 1166 err = ubd_add(i, &error); 1167 if(err) 1168 printk(KERN_ERR "Failed to initialize ubd device %d :" 1169 "%s\n", i, error); 1170 } 1171 mutex_unlock(&ubd_lock); 1172 return 0; 1173 } 1174 1175 late_initcall(ubd_init); 1176 1177 static int __init ubd_driver_init(void){ 1178 unsigned long stack; 1179 int err; 1180 1181 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ 1182 if(global_openflags.s){ 1183 printk(KERN_INFO "ubd: Synchronous mode\n"); 1184 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is 1185 * enough. So use anyway the io thread. */ 1186 } 1187 stack = alloc_stack(0, 0); 1188 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), 1189 &thread_fd); 1190 if(io_pid < 0){ 1191 printk(KERN_ERR 1192 "ubd : Failed to start I/O thread (errno = %d) - " 1193 "falling back to synchronous I/O\n", -io_pid); 1194 io_pid = -1; 1195 return 0; 1196 } 1197 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, 1198 0, "ubd", ubd_devs); 1199 if(err != 0) 1200 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); 1201 return 0; 1202 } 1203 1204 device_initcall(ubd_driver_init); 1205 1206 static int ubd_open(struct block_device *bdev, fmode_t mode) 1207 { 1208 struct gendisk *disk = bdev->bd_disk; 1209 struct ubd *ubd_dev = disk->private_data; 1210 int err = 0; 1211 1212 mutex_lock(&ubd_mutex); 1213 if(ubd_dev->count == 0){ 1214 err = ubd_open_dev(ubd_dev); 1215 if(err){ 1216 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", 1217 disk->disk_name, ubd_dev->file, -err); 1218 goto out; 1219 } 1220 } 1221 ubd_dev->count++; 1222 set_disk_ro(disk, !ubd_dev->openflags.w); 1223 1224 /* This should no more be needed. And it didn't work anyway to exclude 1225 * read-write remounting of filesystems.*/ 1226 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){ 1227 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); 1228 err = -EROFS; 1229 }*/ 1230 out: 1231 mutex_unlock(&ubd_mutex); 1232 return err; 1233 } 1234 1235 static void ubd_release(struct gendisk *disk, fmode_t mode) 1236 { 1237 struct ubd *ubd_dev = disk->private_data; 1238 1239 mutex_lock(&ubd_mutex); 1240 if(--ubd_dev->count == 0) 1241 ubd_close_dev(ubd_dev); 1242 mutex_unlock(&ubd_mutex); 1243 } 1244 1245 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, 1246 __u64 *cow_offset, unsigned long *bitmap, 1247 __u64 bitmap_offset, unsigned long *bitmap_words, 1248 __u64 bitmap_len) 1249 { 1250 __u64 sector = io_offset >> 9; 1251 int i, update_bitmap = 0; 1252 1253 for(i = 0; i < length >> 9; i++){ 1254 if(cow_mask != NULL) 1255 ubd_set_bit(i, (unsigned char *) cow_mask); 1256 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1257 continue; 1258 1259 update_bitmap = 1; 1260 ubd_set_bit(sector + i, (unsigned char *) bitmap); 1261 } 1262 1263 if(!update_bitmap) 1264 return; 1265 1266 *cow_offset = sector / (sizeof(unsigned long) * 8); 1267 1268 /* This takes care of the case where we're exactly at the end of the 1269 * device, and *cow_offset + 1 is off the end. So, just back it up 1270 * by one word. Thanks to Lynn Kerby for the fix and James McMechan 1271 * for the original diagnosis. 1272 */ 1273 if (*cow_offset == (DIV_ROUND_UP(bitmap_len, 1274 sizeof(unsigned long)) - 1)) 1275 (*cow_offset)--; 1276 1277 bitmap_words[0] = bitmap[*cow_offset]; 1278 bitmap_words[1] = bitmap[*cow_offset + 1]; 1279 1280 *cow_offset *= sizeof(unsigned long); 1281 *cow_offset += bitmap_offset; 1282 } 1283 1284 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, 1285 __u64 bitmap_offset, __u64 bitmap_len) 1286 { 1287 __u64 sector = req->offset >> 9; 1288 int i; 1289 1290 if(req->length > (sizeof(req->sector_mask) * 8) << 9) 1291 panic("Operation too long"); 1292 1293 if(req->op == UBD_READ) { 1294 for(i = 0; i < req->length >> 9; i++){ 1295 if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) 1296 ubd_set_bit(i, (unsigned char *) 1297 &req->sector_mask); 1298 } 1299 } 1300 else cowify_bitmap(req->offset, req->length, &req->sector_mask, 1301 &req->cow_offset, bitmap, bitmap_offset, 1302 req->bitmap_words, bitmap_len); 1303 } 1304 1305 /* Called with dev->lock held */ 1306 static void prepare_request(struct request *req, struct io_thread_req *io_req, 1307 unsigned long long offset, int page_offset, 1308 int len, struct page *page) 1309 { 1310 struct gendisk *disk = req->rq_disk; 1311 struct ubd *ubd_dev = disk->private_data; 1312 1313 io_req->req = req; 1314 io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd : 1315 ubd_dev->fd; 1316 io_req->fds[1] = ubd_dev->fd; 1317 io_req->cow_offset = -1; 1318 io_req->offset = offset; 1319 io_req->length = len; 1320 io_req->error = 0; 1321 io_req->sector_mask = 0; 1322 1323 io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; 1324 io_req->offsets[0] = 0; 1325 io_req->offsets[1] = ubd_dev->cow.data_offset; 1326 io_req->buffer = page_address(page) + page_offset; 1327 io_req->sectorsize = 1 << 9; 1328 1329 if(ubd_dev->cow.file != NULL) 1330 cowify_req(io_req, ubd_dev->cow.bitmap, 1331 ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len); 1332 1333 } 1334 1335 /* Called with dev->lock held */ 1336 static void prepare_flush_request(struct request *req, 1337 struct io_thread_req *io_req) 1338 { 1339 struct gendisk *disk = req->rq_disk; 1340 struct ubd *ubd_dev = disk->private_data; 1341 1342 io_req->req = req; 1343 io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd : 1344 ubd_dev->fd; 1345 io_req->op = UBD_FLUSH; 1346 } 1347 1348 static bool submit_request(struct io_thread_req *io_req, struct ubd *dev) 1349 { 1350 int n = os_write_file(thread_fd, &io_req, 1351 sizeof(io_req)); 1352 if (n != sizeof(io_req)) { 1353 if (n != -EAGAIN) 1354 printk("write to io thread failed, " 1355 "errno = %d\n", -n); 1356 else if (list_empty(&dev->restart)) 1357 list_add(&dev->restart, &restart); 1358 1359 kfree(io_req); 1360 return false; 1361 } 1362 return true; 1363 } 1364 1365 /* Called with dev->lock held */ 1366 static void do_ubd_request(struct request_queue *q) 1367 { 1368 struct io_thread_req *io_req; 1369 struct request *req; 1370 1371 while(1){ 1372 struct ubd *dev = q->queuedata; 1373 if(dev->request == NULL){ 1374 struct request *req = blk_fetch_request(q); 1375 if(req == NULL) 1376 return; 1377 1378 dev->request = req; 1379 dev->rq_pos = blk_rq_pos(req); 1380 dev->start_sg = 0; 1381 dev->end_sg = blk_rq_map_sg(q, req, dev->sg); 1382 } 1383 1384 req = dev->request; 1385 1386 if (req_op(req) == REQ_OP_FLUSH) { 1387 io_req = kmalloc(sizeof(struct io_thread_req), 1388 GFP_ATOMIC); 1389 if (io_req == NULL) { 1390 if (list_empty(&dev->restart)) 1391 list_add(&dev->restart, &restart); 1392 return; 1393 } 1394 prepare_flush_request(req, io_req); 1395 if (submit_request(io_req, dev) == false) 1396 return; 1397 } 1398 1399 while(dev->start_sg < dev->end_sg){ 1400 struct scatterlist *sg = &dev->sg[dev->start_sg]; 1401 1402 io_req = kmalloc(sizeof(struct io_thread_req), 1403 GFP_ATOMIC); 1404 if(io_req == NULL){ 1405 if(list_empty(&dev->restart)) 1406 list_add(&dev->restart, &restart); 1407 return; 1408 } 1409 prepare_request(req, io_req, 1410 (unsigned long long)dev->rq_pos << 9, 1411 sg->offset, sg->length, sg_page(sg)); 1412 1413 if (submit_request(io_req, dev) == false) 1414 return; 1415 1416 dev->rq_pos += sg->length >> 9; 1417 dev->start_sg++; 1418 } 1419 dev->end_sg = 0; 1420 dev->request = NULL; 1421 } 1422 } 1423 1424 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) 1425 { 1426 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1427 1428 geo->heads = 128; 1429 geo->sectors = 32; 1430 geo->cylinders = ubd_dev->size / (128 * 32 * 512); 1431 return 0; 1432 } 1433 1434 static int ubd_ioctl(struct block_device *bdev, fmode_t mode, 1435 unsigned int cmd, unsigned long arg) 1436 { 1437 struct ubd *ubd_dev = bdev->bd_disk->private_data; 1438 u16 ubd_id[ATA_ID_WORDS]; 1439 1440 switch (cmd) { 1441 struct cdrom_volctrl volume; 1442 case HDIO_GET_IDENTITY: 1443 memset(&ubd_id, 0, ATA_ID_WORDS * 2); 1444 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); 1445 ubd_id[ATA_ID_HEADS] = 128; 1446 ubd_id[ATA_ID_SECTORS] = 32; 1447 if(copy_to_user((char __user *) arg, (char *) &ubd_id, 1448 sizeof(ubd_id))) 1449 return -EFAULT; 1450 return 0; 1451 1452 case CDROMVOLREAD: 1453 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) 1454 return -EFAULT; 1455 volume.channel0 = 255; 1456 volume.channel1 = 255; 1457 volume.channel2 = 255; 1458 volume.channel3 = 255; 1459 if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) 1460 return -EFAULT; 1461 return 0; 1462 } 1463 return -EINVAL; 1464 } 1465 1466 static int update_bitmap(struct io_thread_req *req) 1467 { 1468 int n; 1469 1470 if(req->cow_offset == -1) 1471 return 0; 1472 1473 n = os_pwrite_file(req->fds[1], &req->bitmap_words, 1474 sizeof(req->bitmap_words), req->cow_offset); 1475 if(n != sizeof(req->bitmap_words)){ 1476 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, 1477 req->fds[1]); 1478 return 1; 1479 } 1480 1481 return 0; 1482 } 1483 1484 static void do_io(struct io_thread_req *req) 1485 { 1486 char *buf; 1487 unsigned long len; 1488 int n, nsectors, start, end, bit; 1489 __u64 off; 1490 1491 if (req->op == UBD_FLUSH) { 1492 /* fds[0] is always either the rw image or our cow file */ 1493 n = os_sync_file(req->fds[0]); 1494 if (n != 0) { 1495 printk("do_io - sync failed err = %d " 1496 "fd = %d\n", -n, req->fds[0]); 1497 req->error = 1; 1498 } 1499 return; 1500 } 1501 1502 nsectors = req->length / req->sectorsize; 1503 start = 0; 1504 do { 1505 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); 1506 end = start; 1507 while((end < nsectors) && 1508 (ubd_test_bit(end, (unsigned char *) 1509 &req->sector_mask) == bit)) 1510 end++; 1511 1512 off = req->offset + req->offsets[bit] + 1513 start * req->sectorsize; 1514 len = (end - start) * req->sectorsize; 1515 buf = &req->buffer[start * req->sectorsize]; 1516 1517 if(req->op == UBD_READ){ 1518 n = 0; 1519 do { 1520 buf = &buf[n]; 1521 len -= n; 1522 n = os_pread_file(req->fds[bit], buf, len, off); 1523 if (n < 0) { 1524 printk("do_io - read failed, err = %d " 1525 "fd = %d\n", -n, req->fds[bit]); 1526 req->error = 1; 1527 return; 1528 } 1529 } while((n < len) && (n != 0)); 1530 if (n < len) memset(&buf[n], 0, len - n); 1531 } else { 1532 n = os_pwrite_file(req->fds[bit], buf, len, off); 1533 if(n != len){ 1534 printk("do_io - write failed err = %d " 1535 "fd = %d\n", -n, req->fds[bit]); 1536 req->error = 1; 1537 return; 1538 } 1539 } 1540 1541 start = end; 1542 } while(start < nsectors); 1543 1544 req->error = update_bitmap(req); 1545 } 1546 1547 /* Changed in start_io_thread, which is serialized by being called only 1548 * from ubd_init, which is an initcall. 1549 */ 1550 int kernel_fd = -1; 1551 1552 /* Only changed by the io thread. XXX: currently unused. */ 1553 static int io_count = 0; 1554 1555 int io_thread(void *arg) 1556 { 1557 int n, count, written, res; 1558 1559 os_fix_helper_signals(); 1560 1561 while(1){ 1562 n = bulk_req_safe_read( 1563 kernel_fd, 1564 io_req_buffer, 1565 &io_remainder, 1566 &io_remainder_size, 1567 UBD_REQ_BUFFER_SIZE 1568 ); 1569 if (n < 0) { 1570 if (n == -EAGAIN) { 1571 ubd_read_poll(-1); 1572 continue; 1573 } else { 1574 printk("io_thread - read failed, fd = %d, " 1575 "err = %d," 1576 "reminder = %d\n", 1577 kernel_fd, -n, io_remainder_size); 1578 } 1579 } 1580 1581 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { 1582 io_count++; 1583 do_io((*io_req_buffer)[count]); 1584 } 1585 1586 written = 0; 1587 1588 do { 1589 res = os_write_file(kernel_fd, ((char *) io_req_buffer) + written, n); 1590 if (res > 0) { 1591 written += res; 1592 } else { 1593 if (res != -EAGAIN) { 1594 printk("io_thread - read failed, fd = %d, " 1595 "err = %d\n", kernel_fd, -n); 1596 } 1597 } 1598 if (written < n) { 1599 ubd_write_poll(-1); 1600 } 1601 } while (written < n); 1602 } 1603 1604 return 0; 1605 } 1606