arch/um/drivers/ubd_kern.c

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