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