arch/um/drivers/ubd_kern.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2018 Cambridge Greys Ltd
   4  * Copyright (C) 2015-2016 Anton Ivanov (aivanov@brocade.com)
   5  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   6  */
   7
   8 /* 2001-09-28...2002-04-17
   9  * Partition stuff by James_McMechan@hotmail.com
  10  * old style ubd by setting UBD_SHIFT to 0
  11  * 2002-09-27...2002-10-18 massive tinkering for 2.5
  12  * partitions have changed in 2.5
  13  * 2003-01-29 more tinkering for 2.5.59-1
  14  * This should now address the sysfs problems and has
  15  * the symlink for devfs to allow for booting with
  16  * the common /dev/ubd/discX/... names rather than
  17  * only /dev/ubdN/discN this version also has lots of
  18  * clean ups preparing for ubd-many.
  19  * James McMechan
  20  */
  21
  22 #define UBD_SHIFT 4
  23
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/blk-mq.h>
  28 #include <linux/ata.h>
  29 #include <linux/hdreg.h>
  30 #include <linux/major.h>
  31 #include <linux/cdrom.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/ctype.h>
  35 #include <linux/slab.h>
  36 #include <linux/vmalloc.h>
  37 #include <linux/platform_device.h>
  38 #include <linux/scatterlist.h>
  39 #include <asm/tlbflush.h>
  40 #include <kern_util.h>
  41 #include "mconsole_kern.h"
  42 #include <init.h>
  43 #include <irq_kern.h>
  44 #include "ubd.h"
  45 #include <os.h>
  46 #include "cow.h"
  47
  48 /* Max request size is determined by sector mask - 32K */
  49 #define UBD_MAX_REQUEST (8 * sizeof(long))
  50
  51 struct io_desc {
  52         char *buffer;
  53         unsigned long length;
  54         unsigned long sector_mask;
  55         unsigned long long cow_offset;
  56         unsigned long bitmap_words[2];
  57 };
  58
  59 struct io_thread_req {
  60         struct request *req;
  61         int fds[2];
  62         unsigned long offsets[2];
  63         unsigned long long offset;
  64         int sectorsize;
  65         int error;
  66
  67         int desc_cnt;
  68         /* io_desc has to be the last element of the struct */
  69         struct io_desc io_desc[];
  70 };
  71
  72
  73 static struct io_thread_req * (*irq_req_buffer)[];
  74 static struct io_thread_req *irq_remainder;
  75 static int irq_remainder_size;
  76
  77 static struct io_thread_req * (*io_req_buffer)[];
  78 static struct io_thread_req *io_remainder;
  79 static int io_remainder_size;
  80
  81
  82
  83 static inline int ubd_test_bit(__u64 bit, unsigned char *data)
  84 {
  85         __u64 n;
  86         int bits, off;
  87
  88         bits = sizeof(data[0]) * 8;
  89         n = bit / bits;
  90         off = bit % bits;
  91         return (data[n] & (1 << off)) != 0;
  92 }
  93
  94 static inline void ubd_set_bit(__u64 bit, unsigned char *data)
  95 {
  96         __u64 n;
  97         int bits, off;
  98
  99         bits = sizeof(data[0]) * 8;
 100         n = bit / bits;
 101         off = bit % bits;
 102         data[n] |= (1 << off);
 103 }
 104 /*End stuff from ubd_user.h*/
 105
 106 #define DRIVER_NAME "uml-blkdev"
 107
 108 static DEFINE_MUTEX(ubd_lock);
 109 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
 110
 111 static int ubd_open(struct gendisk *disk, blk_mode_t mode);
 112 static void ubd_release(struct gendisk *disk);
 113 static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode,
 114                      unsigned int cmd, unsigned long arg);
 115 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
 116
 117 #define MAX_DEV (16)
 118
 119 static const struct block_device_operations ubd_blops = {
 120         .owner          = THIS_MODULE,
 121         .open           = ubd_open,
 122         .release        = ubd_release,
 123         .ioctl          = ubd_ioctl,
 124         .compat_ioctl   = blkdev_compat_ptr_ioctl,
 125         .getgeo         = ubd_getgeo,
 126 };
 127
 128 /* Protected by ubd_lock */
 129 static struct gendisk *ubd_gendisk[MAX_DEV];
 130
 131 #ifdef CONFIG_BLK_DEV_UBD_SYNC
 132 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
 133                                          .cl = 1 })
 134 #else
 135 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
 136                                          .cl = 1 })
 137 #endif
 138 static struct openflags global_openflags = OPEN_FLAGS;
 139
 140 struct cow {
 141         /* backing file name */
 142         char *file;
 143         /* backing file fd */
 144         int fd;
 145         unsigned long *bitmap;
 146         unsigned long bitmap_len;
 147         int bitmap_offset;
 148         int data_offset;
 149 };
 150
 151 #define MAX_SG 64
 152
 153 struct ubd {
 154         /* name (and fd, below) of the file opened for writing, either the
 155          * backing or the cow file. */
 156         char *file;
 157         char *serial;
 158         int count;
 159         int fd;
 160         __u64 size;
 161         struct openflags boot_openflags;
 162         struct openflags openflags;
 163         unsigned shared:1;
 164         unsigned no_cow:1;
 165         unsigned no_trim:1;
 166         struct cow cow;
 167         struct platform_device pdev;
 168         struct request_queue *queue;
 169         struct blk_mq_tag_set tag_set;
 170         spinlock_t lock;
 171 };
 172
 173 #define DEFAULT_COW { \
 174         .file =                 NULL, \
 175         .fd =                   -1,     \
 176         .bitmap =               NULL, \
 177         .bitmap_offset =        0, \
 178         .data_offset =          0, \
 179 }
 180
 181 #define DEFAULT_UBD { \
 182         .file =                 NULL, \
 183         .serial =               NULL, \
 184         .count =                0, \
 185         .fd =                   -1, \
 186         .size =                 -1, \
 187         .boot_openflags =       OPEN_FLAGS, \
 188         .openflags =            OPEN_FLAGS, \
 189         .no_cow =               0, \
 190         .no_trim =              0, \
 191         .shared =               0, \
 192         .cow =                  DEFAULT_COW, \
 193         .lock =                 __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
 194 }
 195
 196 /* Protected by ubd_lock */
 197 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
 198
 199 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
 200                                  const struct blk_mq_queue_data *bd);
 201
 202 static int fake_ide_setup(char *str)
 203 {
 204         pr_warn("The fake_ide option has been removed\n");
 205         return 1;
 206 }
 207 __setup("fake_ide", fake_ide_setup);
 208
 209 __uml_help(fake_ide_setup,
 210 "fake_ide\n"
 211 "    Obsolete stub.\n\n"
 212 );
 213
 214 static int parse_unit(char **ptr)
 215 {
 216         char *str = *ptr, *end;
 217         int n = -1;
 218
 219         if(isdigit(*str)) {
 220                 n = simple_strtoul(str, &end, 0);
 221                 if(end == str)
 222                         return -1;
 223                 *ptr = end;
 224         }
 225         else if (('a' <= *str) && (*str <= 'z')) {
 226                 n = *str - 'a';
 227                 str++;
 228                 *ptr = str;
 229         }
 230         return n;
 231 }
 232
 233 /* If *index_out == -1 at exit, the passed option was a general one;
 234  * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
 235  * should not be freed on exit.
 236  */
 237 static int ubd_setup_common(char *str, int *index_out, char **error_out)
 238 {
 239         struct ubd *ubd_dev;
 240         struct openflags flags = global_openflags;
 241         char *file, *backing_file, *serial;
 242         int n, err = 0, i;
 243
 244         if(index_out) *index_out = -1;
 245         n = *str;
 246         if(n == '='){
 247                 str++;
 248                 if(!strcmp(str, "sync")){
 249                         global_openflags = of_sync(global_openflags);
 250                         return err;
 251                 }
 252
 253                 pr_warn("fake major not supported any more\n");
 254                 return 0;
 255         }
 256
 257         n = parse_unit(&str);
 258         if(n < 0){
 259                 *error_out = "Couldn't parse device number";
 260                 return -EINVAL;
 261         }
 262         if(n >= MAX_DEV){
 263                 *error_out = "Device number out of range";
 264                 return 1;
 265         }
 266
 267         err = -EBUSY;
 268         mutex_lock(&ubd_lock);
 269
 270         ubd_dev = &ubd_devs[n];
 271         if(ubd_dev->file != NULL){
 272                 *error_out = "Device is already configured";
 273                 goto out;
 274         }
 275
 276         if (index_out)
 277                 *index_out = n;
 278
 279         err = -EINVAL;
 280         for (i = 0; i < sizeof("rscdt="); i++) {
 281                 switch (*str) {
 282                 case 'r':
 283                         flags.w = 0;
 284                         break;
 285                 case 's':
 286                         flags.s = 1;
 287                         break;
 288                 case 'd':
 289                         ubd_dev->no_cow = 1;
 290                         break;
 291                 case 'c':
 292                         ubd_dev->shared = 1;
 293                         break;
 294                 case 't':
 295                         ubd_dev->no_trim = 1;
 296                         break;
 297                 case '=':
 298                         str++;
 299                         goto break_loop;
 300                 default:
 301                         *error_out = "Expected '=' or flag letter "
 302                                 "(r, s, c, t or d)";
 303                         goto out;
 304                 }
 305                 str++;
 306         }
 307
 308         if (*str == '=')
 309                 *error_out = "Too many flags specified";
 310         else
 311                 *error_out = "Missing '='";
 312         goto out;
 313
 314 break_loop:
 315         file = strsep(&str, ",:");
 316         if (*file == '\0')
 317                 file = NULL;
 318
 319         backing_file = strsep(&str, ",:");
 320         if (backing_file && *backing_file == '\0')
 321                 backing_file = NULL;
 322
 323         serial = strsep(&str, ",:");
 324         if (serial && *serial == '\0')
 325                 serial = NULL;
 326
 327         if (backing_file && ubd_dev->no_cow) {
 328                 *error_out = "Can't specify both 'd' and a cow file";
 329                 goto out;
 330         }
 331
 332         err = 0;
 333         ubd_dev->file = file;
 334         ubd_dev->cow.file = backing_file;
 335         ubd_dev->serial = serial;
 336         ubd_dev->boot_openflags = flags;
 337 out:
 338         mutex_unlock(&ubd_lock);
 339         return err;
 340 }
 341
 342 static int ubd_setup(char *str)
 343 {
 344         char *error;
 345         int err;
 346
 347         err = ubd_setup_common(str, NULL, &error);
 348         if(err)
 349                 printk(KERN_ERR "Failed to initialize device with \"%s\" : "
 350                        "%s\n", str, error);
 351         return 1;
 352 }
 353
 354 __setup("ubd", ubd_setup);
 355 __uml_help(ubd_setup,
 356 "ubd<n><flags>=<filename>[(:|,)<filename2>][(:|,)<serial>]\n"
 357 "    This is used to associate a device with a file in the underlying\n"
 358 "    filesystem. When specifying two filenames, the first one is the\n"
 359 "    COW name and the second is the backing file name. As separator you can\n"
 360 "    use either a ':' or a ',': the first one allows writing things like;\n"
 361 "       ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
 362 "    while with a ',' the shell would not expand the 2nd '~'.\n"
 363 "    When using only one filename, UML will detect whether to treat it like\n"
 364 "    a COW file or a backing file. To override this detection, add the 'd'\n"
 365 "    flag:\n"
 366 "       ubd0d=BackingFile\n"
 367 "    Usually, there is a filesystem in the file, but \n"
 368 "    that's not required. Swap devices containing swap files can be\n"
 369 "    specified like this. Also, a file which doesn't contain a\n"
 370 "    filesystem can have its contents read in the virtual \n"
 371 "    machine by running 'dd' on the device. <n> must be in the range\n"
 372 "    0 to 7. Appending an 'r' to the number will cause that device\n"
 373 "    to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
 374 "    an 's' will cause data to be written to disk on the host immediately.\n"
 375 "    'c' will cause the device to be treated as being shared between multiple\n"
 376 "    UMLs and file locking will be turned off - this is appropriate for a\n"
 377 "    cluster filesystem and inappropriate at almost all other times.\n\n"
 378 "    't' will disable trim/discard support on the device (enabled by default).\n\n"
 379 "    An optional device serial number can be exposed using the serial parameter\n"
 380 "    on the cmdline which is exposed as a sysfs entry. This is particularly\n"
 381 "    useful when a unique number should be given to the device. Note when\n"
 382 "    specifying a label, the filename2 must be also presented. It can be\n"
 383 "    an empty string, in which case the backing file is not used:\n"
 384 "       ubd0=File,,Serial\n"
 385 );
 386
 387 static int udb_setup(char *str)
 388 {
 389         printk("udb%s specified on command line is almost certainly a ubd -> "
 390                "udb TYPO\n", str);
 391         return 1;
 392 }
 393
 394 __setup("udb", udb_setup);
 395 __uml_help(udb_setup,
 396 "udb\n"
 397 "    This option is here solely to catch ubd -> udb typos, which can be\n"
 398 "    to impossible to catch visually unless you specifically look for\n"
 399 "    them.  The only result of any option starting with 'udb' is an error\n"
 400 "    in the boot output.\n\n"
 401 );
 402
 403 /* Only changed by ubd_init, which is an initcall. */
 404 static int thread_fd = -1;
 405
 406 /* Function to read several request pointers at a time
 407 * handling fractional reads if (and as) needed
 408 */
 409
 410 static int bulk_req_safe_read(
 411         int fd,
 412         struct io_thread_req * (*request_buffer)[],
 413         struct io_thread_req **remainder,
 414         int *remainder_size,
 415         int max_recs
 416         )
 417 {
 418         int n = 0;
 419         int res = 0;
 420
 421         if (*remainder_size > 0) {
 422                 memmove(
 423                         (char *) request_buffer,
 424                         (char *) remainder, *remainder_size
 425                 );
 426                 n = *remainder_size;
 427         }
 428
 429         res = os_read_file(
 430                         fd,
 431                         ((char *) request_buffer) + *remainder_size,
 432                         sizeof(struct io_thread_req *)*max_recs
 433                                 - *remainder_size
 434                 );
 435         if (res > 0) {
 436                 n += res;
 437                 if ((n % sizeof(struct io_thread_req *)) > 0) {
 438                         /*
 439                         * Read somehow returned not a multiple of dword
 440                         * theoretically possible, but never observed in the
 441                         * wild, so read routine must be able to handle it
 442                         */
 443                         *remainder_size = n % sizeof(struct io_thread_req *);
 444                         WARN(*remainder_size > 0, "UBD IPC read returned a partial result");
 445                         memmove(
 446                                 remainder,
 447                                 ((char *) request_buffer) +
 448                                         (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *),
 449                                 *remainder_size
 450                         );
 451                         n = n - *remainder_size;
 452                 }
 453         } else {
 454                 n = res;
 455         }
 456         return n;
 457 }
 458
 459 /* Called without dev->lock held, and only in interrupt context. */
 460 static void ubd_handler(void)
 461 {
 462         int n;
 463         int count;
 464
 465         while(1){
 466                 n = bulk_req_safe_read(
 467                         thread_fd,
 468                         irq_req_buffer,
 469                         &irq_remainder,
 470                         &irq_remainder_size,
 471                         UBD_REQ_BUFFER_SIZE
 472                 );
 473                 if (n < 0) {
 474                         if(n == -EAGAIN)
 475                                 break;
 476                         printk(KERN_ERR "spurious interrupt in ubd_handler, "
 477                                "err = %d\n", -n);
 478                         return;
 479                 }
 480                 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
 481                         struct io_thread_req *io_req = (*irq_req_buffer)[count];
 482
 483                         if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
 484                                 blk_queue_max_discard_sectors(io_req->req->q, 0);
 485                                 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
 486                         }
 487                         blk_mq_end_request(io_req->req, io_req->error);
 488                         kfree(io_req);
 489                 }
 490         }
 491 }
 492
 493 static irqreturn_t ubd_intr(int irq, void *dev)
 494 {
 495         ubd_handler();
 496         return IRQ_HANDLED;
 497 }
 498
 499 /* Only changed by ubd_init, which is an initcall. */
 500 static int io_pid = -1;
 501
 502 static void kill_io_thread(void)
 503 {
 504         if(io_pid != -1)
 505                 os_kill_process(io_pid, 1);
 506 }
 507
 508 __uml_exitcall(kill_io_thread);
 509
 510 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
 511 {
 512         char *file;
 513         int fd;
 514         int err;
 515
 516         __u32 version;
 517         __u32 align;
 518         char *backing_file;
 519         time64_t mtime;
 520         unsigned long long size;
 521         int sector_size;
 522         int bitmap_offset;
 523
 524         if (ubd_dev->file && ubd_dev->cow.file) {
 525                 file = ubd_dev->cow.file;
 526
 527                 goto out;
 528         }
 529
 530         fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0);
 531         if (fd < 0)
 532                 return fd;
 533
 534         err = read_cow_header(file_reader, &fd, &version, &backing_file, \
 535                 &mtime, &size, &sector_size, &align, &bitmap_offset);
 536         os_close_file(fd);
 537
 538         if(err == -EINVAL)
 539                 file = ubd_dev->file;
 540         else
 541                 file = backing_file;
 542
 543 out:
 544         return os_file_size(file, size_out);
 545 }
 546
 547 static int read_cow_bitmap(int fd, void *buf, int offset, int len)
 548 {
 549         int err;
 550
 551         err = os_pread_file(fd, buf, len, offset);
 552         if (err < 0)
 553                 return err;
 554
 555         return 0;
 556 }
 557
 558 static int backing_file_mismatch(char *file, __u64 size, time64_t mtime)
 559 {
 560         time64_t modtime;
 561         unsigned long long actual;
 562         int err;
 563
 564         err = os_file_modtime(file, &modtime);
 565         if (err < 0) {
 566                 printk(KERN_ERR "Failed to get modification time of backing "
 567                        "file \"%s\", err = %d\n", file, -err);
 568                 return err;
 569         }
 570
 571         err = os_file_size(file, &actual);
 572         if (err < 0) {
 573                 printk(KERN_ERR "Failed to get size of backing file \"%s\", "
 574                        "err = %d\n", file, -err);
 575                 return err;
 576         }
 577
 578         if (actual != size) {
 579                 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
 580                  * the typecast.*/
 581                 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header "
 582                        "vs backing file\n", (unsigned long long) size, actual);
 583                 return -EINVAL;
 584         }
 585         if (modtime != mtime) {
 586                 printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs "
 587                        "backing file\n", mtime, modtime);
 588                 return -EINVAL;
 589         }
 590         return 0;
 591 }
 592
 593 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
 594 {
 595         struct uml_stat buf1, buf2;
 596         int err;
 597
 598         if (from_cmdline == NULL)
 599                 return 0;
 600         if (!strcmp(from_cmdline, from_cow))
 601                 return 0;
 602
 603         err = os_stat_file(from_cmdline, &buf1);
 604         if (err < 0) {
 605                 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline,
 606                        -err);
 607                 return 0;
 608         }
 609         err = os_stat_file(from_cow, &buf2);
 610         if (err < 0) {
 611                 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow,
 612                        -err);
 613                 return 1;
 614         }
 615         if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
 616                 return 0;
 617
 618         printk(KERN_ERR "Backing file mismatch - \"%s\" requested, "
 619                "\"%s\" specified in COW header of \"%s\"\n",
 620                from_cmdline, from_cow, cow);
 621         return 1;
 622 }
 623
 624 static int open_ubd_file(char *file, struct openflags *openflags, int shared,
 625                   char **backing_file_out, int *bitmap_offset_out,
 626                   unsigned long *bitmap_len_out, int *data_offset_out,
 627                   int *create_cow_out)
 628 {
 629         time64_t mtime;
 630         unsigned long long size;
 631         __u32 version, align;
 632         char *backing_file;
 633         int fd, err, sectorsize, asked_switch, mode = 0644;
 634
 635         fd = os_open_file(file, *openflags, mode);
 636         if (fd < 0) {
 637                 if ((fd == -ENOENT) && (create_cow_out != NULL))
 638                         *create_cow_out = 1;
 639                 if (!openflags->w ||
 640                     ((fd != -EROFS) && (fd != -EACCES)))
 641                         return fd;
 642                 openflags->w = 0;
 643                 fd = os_open_file(file, *openflags, mode);
 644                 if (fd < 0)
 645                         return fd;
 646         }
 647
 648         if (shared)
 649                 printk(KERN_INFO "Not locking \"%s\" on the host\n", file);
 650         else {
 651                 err = os_lock_file(fd, openflags->w);
 652                 if (err < 0) {
 653                         printk(KERN_ERR "Failed to lock '%s', err = %d\n",
 654                                file, -err);
 655                         goto out_close;
 656                 }
 657         }
 658
 659         /* Successful return case! */
 660         if (backing_file_out == NULL)
 661                 return fd;
 662
 663         err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
 664                               &size, &sectorsize, &align, bitmap_offset_out);
 665         if (err && (*backing_file_out != NULL)) {
 666                 printk(KERN_ERR "Failed to read COW header from COW file "
 667                        "\"%s\", errno = %d\n", file, -err);
 668                 goto out_close;
 669         }
 670         if (err)
 671                 return fd;
 672
 673         asked_switch = path_requires_switch(*backing_file_out, backing_file,
 674                                             file);
 675
 676         /* Allow switching only if no mismatch. */
 677         if (asked_switch && !backing_file_mismatch(*backing_file_out, size,
 678                                                    mtime)) {
 679                 printk(KERN_ERR "Switching backing file to '%s'\n",
 680                        *backing_file_out);
 681                 err = write_cow_header(file, fd, *backing_file_out,
 682                                        sectorsize, align, &size);
 683                 if (err) {
 684                         printk(KERN_ERR "Switch failed, errno = %d\n", -err);
 685                         goto out_close;
 686                 }
 687         } else {
 688                 *backing_file_out = backing_file;
 689                 err = backing_file_mismatch(*backing_file_out, size, mtime);
 690                 if (err)
 691                         goto out_close;
 692         }
 693
 694         cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
 695                   bitmap_len_out, data_offset_out);
 696
 697         return fd;
 698  out_close:
 699         os_close_file(fd);
 700         return err;
 701 }
 702
 703 static int create_cow_file(char *cow_file, char *backing_file,
 704                     struct openflags flags,
 705                     int sectorsize, int alignment, int *bitmap_offset_out,
 706                     unsigned long *bitmap_len_out, int *data_offset_out)
 707 {
 708         int err, fd;
 709
 710         flags.c = 1;
 711         fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL);
 712         if (fd < 0) {
 713                 err = fd;
 714                 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n",
 715                        cow_file, -err);
 716                 goto out;
 717         }
 718
 719         err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
 720                             bitmap_offset_out, bitmap_len_out,
 721                             data_offset_out);
 722         if (!err)
 723                 return fd;
 724         os_close_file(fd);
 725  out:
 726         return err;
 727 }
 728
 729 static void ubd_close_dev(struct ubd *ubd_dev)
 730 {
 731         os_close_file(ubd_dev->fd);
 732         if(ubd_dev->cow.file == NULL)
 733                 return;
 734
 735         os_close_file(ubd_dev->cow.fd);
 736         vfree(ubd_dev->cow.bitmap);
 737         ubd_dev->cow.bitmap = NULL;
 738 }
 739
 740 static int ubd_open_dev(struct ubd *ubd_dev)
 741 {
 742         struct openflags flags;
 743         char **back_ptr;
 744         int err, create_cow, *create_ptr;
 745         int fd;
 746
 747         ubd_dev->openflags = ubd_dev->boot_openflags;
 748         create_cow = 0;
 749         create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
 750         back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;
 751
 752         fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
 753                                 back_ptr, &ubd_dev->cow.bitmap_offset,
 754                                 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
 755                                 create_ptr);
 756
 757         if((fd == -ENOENT) && create_cow){
 758                 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
 759                                           ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE,
 760                                           &ubd_dev->cow.bitmap_offset,
 761                                           &ubd_dev->cow.bitmap_len,
 762                                           &ubd_dev->cow.data_offset);
 763                 if(fd >= 0){
 764                         printk(KERN_INFO "Creating \"%s\" as COW file for "
 765                                "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
 766                 }
 767         }
 768
 769         if(fd < 0){
 770                 printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
 771                        -fd);
 772                 return fd;
 773         }
 774         ubd_dev->fd = fd;
 775
 776         if(ubd_dev->cow.file != NULL){
 777                 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long));
 778
 779                 err = -ENOMEM;
 780                 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
 781                 if(ubd_dev->cow.bitmap == NULL){
 782                         printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
 783                         goto error;
 784                 }
 785                 flush_tlb_kernel_vm();
 786
 787                 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
 788                                       ubd_dev->cow.bitmap_offset,
 789                                       ubd_dev->cow.bitmap_len);
 790                 if(err < 0)
 791                         goto error;
 792
 793                 flags = ubd_dev->openflags;
 794                 flags.w = 0;
 795                 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
 796                                     NULL, NULL, NULL, NULL);
 797                 if(err < 0) goto error;
 798                 ubd_dev->cow.fd = err;
 799         }
 800         if (ubd_dev->no_trim == 0) {
 801                 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
 802                 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
 803                 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
 804         }
 805         blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
 806         return 0;
 807  error:
 808         os_close_file(ubd_dev->fd);
 809         return err;
 810 }
 811
 812 static void ubd_device_release(struct device *dev)
 813 {
 814         struct ubd *ubd_dev = dev_get_drvdata(dev);
 815
 816         blk_mq_free_tag_set(&ubd_dev->tag_set);
 817         *ubd_dev = ((struct ubd) DEFAULT_UBD);
 818 }
 819
 820 static ssize_t serial_show(struct device *dev,
 821                            struct device_attribute *attr, char *buf)
 822 {
 823         struct gendisk *disk = dev_to_disk(dev);
 824         struct ubd *ubd_dev = disk->private_data;
 825
 826         if (!ubd_dev)
 827                 return 0;
 828
 829         return sprintf(buf, "%s", ubd_dev->serial);
 830 }
 831
 832 static DEVICE_ATTR_RO(serial);
 833
 834 static struct attribute *ubd_attrs[] = {
 835         &dev_attr_serial.attr,
 836         NULL,
 837 };
 838
 839 static umode_t ubd_attrs_are_visible(struct kobject *kobj,
 840                                      struct attribute *a, int n)
 841 {
 842         return a->mode;
 843 }
 844
 845 static const struct attribute_group ubd_attr_group = {
 846         .attrs = ubd_attrs,
 847         .is_visible = ubd_attrs_are_visible,
 848 };
 849
 850 static const struct attribute_group *ubd_attr_groups[] = {
 851         &ubd_attr_group,
 852         NULL,
 853 };
 854
 855 static int ubd_disk_register(int major, u64 size, int unit,
 856                              struct gendisk *disk)
 857 {
 858         disk->major = major;
 859         disk->first_minor = unit << UBD_SHIFT;
 860         disk->minors = 1 << UBD_SHIFT;
 861         disk->fops = &ubd_blops;
 862         set_capacity(disk, size / 512);
 863         sprintf(disk->disk_name, "ubd%c", 'a' + unit);
 864
 865         ubd_devs[unit].pdev.id   = unit;
 866         ubd_devs[unit].pdev.name = DRIVER_NAME;
 867         ubd_devs[unit].pdev.dev.release = ubd_device_release;
 868         dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
 869         platform_device_register(&ubd_devs[unit].pdev);
 870
 871         disk->private_data = &ubd_devs[unit];
 872         disk->queue = ubd_devs[unit].queue;
 873         return device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups);
 874 }
 875
 876 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
 877
 878 static const struct blk_mq_ops ubd_mq_ops = {
 879         .queue_rq = ubd_queue_rq,
 880 };
 881
 882 static int ubd_add(int n, char **error_out)
 883 {
 884         struct ubd *ubd_dev = &ubd_devs[n];
 885         struct gendisk *disk;
 886         int err = 0;
 887
 888         if(ubd_dev->file == NULL)
 889                 goto out;
 890
 891         err = ubd_file_size(ubd_dev, &ubd_dev->size);
 892         if(err < 0){
 893                 *error_out = "Couldn't determine size of device's file";
 894                 goto out;
 895         }
 896
 897         ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
 898
 899         ubd_dev->tag_set.ops = &ubd_mq_ops;
 900         ubd_dev->tag_set.queue_depth = 64;
 901         ubd_dev->tag_set.numa_node = NUMA_NO_NODE;
 902         ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
 903         ubd_dev->tag_set.driver_data = ubd_dev;
 904         ubd_dev->tag_set.nr_hw_queues = 1;
 905
 906         err = blk_mq_alloc_tag_set(&ubd_dev->tag_set);
 907         if (err)
 908                 goto out;
 909
 910         disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
 911         if (IS_ERR(disk)) {
 912                 err = PTR_ERR(disk);
 913                 goto out_cleanup_tags;
 914         }
 915         ubd_dev->queue = disk->queue;
 916
 917         blk_queue_write_cache(ubd_dev->queue, true, false);
 918         blk_queue_max_segments(ubd_dev->queue, MAX_SG);
 919         blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1);
 920         err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk);
 921         if (err)
 922                 goto out_cleanup_disk;
 923
 924         ubd_gendisk[n] = disk;
 925         return 0;
 926
 927 out_cleanup_disk:
 928         put_disk(disk);
 929 out_cleanup_tags:
 930         blk_mq_free_tag_set(&ubd_dev->tag_set);
 931 out:
 932         return err;
 933 }
 934
 935 static int ubd_config(char *str, char **error_out)
 936 {
 937         int n, ret;
 938
 939         /* This string is possibly broken up and stored, so it's only
 940          * freed if ubd_setup_common fails, or if only general options
 941          * were set.
 942          */
 943         str = kstrdup(str, GFP_KERNEL);
 944         if (str == NULL) {
 945                 *error_out = "Failed to allocate memory";
 946                 return -ENOMEM;
 947         }
 948
 949         ret = ubd_setup_common(str, &n, error_out);
 950         if (ret)
 951                 goto err_free;
 952
 953         if (n == -1) {
 954                 ret = 0;
 955                 goto err_free;
 956         }
 957
 958         mutex_lock(&ubd_lock);
 959         ret = ubd_add(n, error_out);
 960         if (ret)
 961                 ubd_devs[n].file = NULL;
 962         mutex_unlock(&ubd_lock);
 963
 964 out:
 965         return ret;
 966
 967 err_free:
 968         kfree(str);
 969         goto out;
 970 }
 971
 972 static int ubd_get_config(char *name, char *str, int size, char **error_out)
 973 {
 974         struct ubd *ubd_dev;
 975         int n, len = 0;
 976
 977         n = parse_unit(&name);
 978         if((n >= MAX_DEV) || (n < 0)){
 979                 *error_out = "ubd_get_config : device number out of range";
 980                 return -1;
 981         }
 982
 983         ubd_dev = &ubd_devs[n];
 984         mutex_lock(&ubd_lock);
 985
 986         if(ubd_dev->file == NULL){
 987                 CONFIG_CHUNK(str, size, len, "", 1);
 988                 goto out;
 989         }
 990
 991         CONFIG_CHUNK(str, size, len, ubd_dev->file, 0);
 992
 993         if(ubd_dev->cow.file != NULL){
 994                 CONFIG_CHUNK(str, size, len, ",", 0);
 995                 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1);
 996         }
 997         else CONFIG_CHUNK(str, size, len, "", 1);
 998
 999  out:
1000         mutex_unlock(&ubd_lock);
1001         return len;
1002 }
1003
1004 static int ubd_id(char **str, int *start_out, int *end_out)
1005 {
1006         int n;
1007
1008         n = parse_unit(str);
1009         *start_out = 0;
1010         *end_out = MAX_DEV - 1;
1011         return n;
1012 }
1013
1014 static int ubd_remove(int n, char **error_out)
1015 {
1016         struct gendisk *disk = ubd_gendisk[n];
1017         struct ubd *ubd_dev;
1018         int err = -ENODEV;
1019
1020         mutex_lock(&ubd_lock);
1021
1022         ubd_dev = &ubd_devs[n];
1023
1024         if(ubd_dev->file == NULL)
1025                 goto out;
1026
1027         /* you cannot remove a open disk */
1028         err = -EBUSY;
1029         if(ubd_dev->count > 0)
1030                 goto out;
1031
1032         ubd_gendisk[n] = NULL;
1033         if(disk != NULL){
1034                 del_gendisk(disk);
1035                 put_disk(disk);
1036         }
1037
1038         err = 0;
1039         platform_device_unregister(&ubd_dev->pdev);
1040 out:
1041         mutex_unlock(&ubd_lock);
1042         return err;
1043 }
1044
1045 /* All these are called by mconsole in process context and without
1046  * ubd-specific locks.  The structure itself is const except for .list.
1047  */
1048 static struct mc_device ubd_mc = {
1049         .list           = LIST_HEAD_INIT(ubd_mc.list),
1050         .name           = "ubd",
1051         .config         = ubd_config,
1052         .get_config     = ubd_get_config,
1053         .id             = ubd_id,
1054         .remove         = ubd_remove,
1055 };
1056
1057 static int __init ubd_mc_init(void)
1058 {
1059         mconsole_register_dev(&ubd_mc);
1060         return 0;
1061 }
1062
1063 __initcall(ubd_mc_init);
1064
1065 static int __init ubd0_init(void)
1066 {
1067         struct ubd *ubd_dev = &ubd_devs[0];
1068
1069         mutex_lock(&ubd_lock);
1070         if(ubd_dev->file == NULL)
1071                 ubd_dev->file = "root_fs";
1072         mutex_unlock(&ubd_lock);
1073
1074         return 0;
1075 }
1076
1077 __initcall(ubd0_init);
1078
1079 /* Used in ubd_init, which is an initcall */
1080 static struct platform_driver ubd_driver = {
1081         .driver = {
1082                 .name  = DRIVER_NAME,
1083         },
1084 };
1085
1086 static int __init ubd_init(void)
1087 {
1088         char *error;
1089         int i, err;
1090
1091         if (register_blkdev(UBD_MAJOR, "ubd"))
1092                 return -1;
1093
1094         irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1095                                        sizeof(struct io_thread_req *),
1096                                        GFP_KERNEL
1097                 );
1098         irq_remainder = 0;
1099
1100         if (irq_req_buffer == NULL) {
1101                 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1102                 return -1;
1103         }
1104         io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1105                                       sizeof(struct io_thread_req *),
1106                                       GFP_KERNEL
1107                 );
1108
1109         io_remainder = 0;
1110
1111         if (io_req_buffer == NULL) {
1112                 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1113                 return -1;
1114         }
1115         platform_driver_register(&ubd_driver);
1116         mutex_lock(&ubd_lock);
1117         for (i = 0; i < MAX_DEV; i++){
1118                 err = ubd_add(i, &error);
1119                 if(err)
1120                         printk(KERN_ERR "Failed to initialize ubd device %d :"
1121                                "%s\n", i, error);
1122         }
1123         mutex_unlock(&ubd_lock);
1124         return 0;
1125 }
1126
1127 late_initcall(ubd_init);
1128
1129 static int __init ubd_driver_init(void){
1130         unsigned long stack;
1131         int err;
1132
1133         /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
1134         if(global_openflags.s){
1135                 printk(KERN_INFO "ubd: Synchronous mode\n");
1136                 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
1137                  * enough. So use anyway the io thread. */
1138         }
1139         stack = alloc_stack(0, 0);
1140         io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd);
1141         if(io_pid < 0){
1142                 printk(KERN_ERR
1143                        "ubd : Failed to start I/O thread (errno = %d) - "
1144                        "falling back to synchronous I/O\n", -io_pid);
1145                 io_pid = -1;
1146                 return 0;
1147         }
1148         err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
1149                              0, "ubd", ubd_devs);
1150         if(err < 0)
1151                 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
1152         return 0;
1153 }
1154
1155 device_initcall(ubd_driver_init);
1156
1157 static int ubd_open(struct gendisk *disk, blk_mode_t mode)
1158 {
1159         struct ubd *ubd_dev = disk->private_data;
1160         int err = 0;
1161
1162         mutex_lock(&ubd_mutex);
1163         if(ubd_dev->count == 0){
1164                 err = ubd_open_dev(ubd_dev);
1165                 if(err){
1166                         printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
1167                                disk->disk_name, ubd_dev->file, -err);
1168                         goto out;
1169                 }
1170         }
1171         ubd_dev->count++;
1172         set_disk_ro(disk, !ubd_dev->openflags.w);
1173 out:
1174         mutex_unlock(&ubd_mutex);
1175         return err;
1176 }
1177
1178 static void ubd_release(struct gendisk *disk)
1179 {
1180         struct ubd *ubd_dev = disk->private_data;
1181
1182         mutex_lock(&ubd_mutex);
1183         if(--ubd_dev->count == 0)
1184                 ubd_close_dev(ubd_dev);
1185         mutex_unlock(&ubd_mutex);
1186 }
1187
1188 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
1189                           __u64 *cow_offset, unsigned long *bitmap,
1190                           __u64 bitmap_offset, unsigned long *bitmap_words,
1191                           __u64 bitmap_len)
1192 {
1193         __u64 sector = io_offset >> SECTOR_SHIFT;
1194         int i, update_bitmap = 0;
1195
1196         for (i = 0; i < length >> SECTOR_SHIFT; i++) {
1197                 if(cow_mask != NULL)
1198                         ubd_set_bit(i, (unsigned char *) cow_mask);
1199                 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1200                         continue;
1201
1202                 update_bitmap = 1;
1203                 ubd_set_bit(sector + i, (unsigned char *) bitmap);
1204         }
1205
1206         if(!update_bitmap)
1207                 return;
1208
1209         *cow_offset = sector / (sizeof(unsigned long) * 8);
1210
1211         /* This takes care of the case where we're exactly at the end of the
1212          * device, and *cow_offset + 1 is off the end.  So, just back it up
1213          * by one word.  Thanks to Lynn Kerby for the fix and James McMechan
1214          * for the original diagnosis.
1215          */
1216         if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
1217                                          sizeof(unsigned long)) - 1))
1218                 (*cow_offset)--;
1219
1220         bitmap_words[0] = bitmap[*cow_offset];
1221         bitmap_words[1] = bitmap[*cow_offset + 1];
1222
1223         *cow_offset *= sizeof(unsigned long);
1224         *cow_offset += bitmap_offset;
1225 }
1226
1227 static void cowify_req(struct io_thread_req *req, struct io_desc *segment,
1228                        unsigned long offset, unsigned long *bitmap,
1229                        __u64 bitmap_offset, __u64 bitmap_len)
1230 {
1231         __u64 sector = offset >> SECTOR_SHIFT;
1232         int i;
1233
1234         if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT)
1235                 panic("Operation too long");
1236
1237         if (req_op(req->req) == REQ_OP_READ) {
1238                 for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) {
1239                         if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1240                                 ubd_set_bit(i, (unsigned char *)
1241                                             &segment->sector_mask);
1242                 }
1243         } else {
1244                 cowify_bitmap(offset, segment->length, &segment->sector_mask,
1245                               &segment->cow_offset, bitmap, bitmap_offset,
1246                               segment->bitmap_words, bitmap_len);
1247         }
1248 }
1249
1250 static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req,
1251                         struct request *req)
1252 {
1253         struct bio_vec bvec;
1254         struct req_iterator iter;
1255         int i = 0;
1256         unsigned long byte_offset = io_req->offset;
1257         enum req_op op = req_op(req);
1258
1259         if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) {
1260                 io_req->io_desc[0].buffer = NULL;
1261                 io_req->io_desc[0].length = blk_rq_bytes(req);
1262         } else {
1263                 rq_for_each_segment(bvec, req, iter) {
1264                         BUG_ON(i >= io_req->desc_cnt);
1265
1266                         io_req->io_desc[i].buffer = bvec_virt(&bvec);
1267                         io_req->io_desc[i].length = bvec.bv_len;
1268                         i++;
1269                 }
1270         }
1271
1272         if (dev->cow.file) {
1273                 for (i = 0; i < io_req->desc_cnt; i++) {
1274                         cowify_req(io_req, &io_req->io_desc[i], byte_offset,
1275                                    dev->cow.bitmap, dev->cow.bitmap_offset,
1276                                    dev->cow.bitmap_len);
1277                         byte_offset += io_req->io_desc[i].length;
1278                 }
1279
1280         }
1281 }
1282
1283 static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req,
1284                                            int desc_cnt)
1285 {
1286         struct io_thread_req *io_req;
1287         int i;
1288
1289         io_req = kmalloc(sizeof(*io_req) +
1290                          (desc_cnt * sizeof(struct io_desc)),
1291                          GFP_ATOMIC);
1292         if (!io_req)
1293                 return NULL;
1294
1295         io_req->req = req;
1296         if (dev->cow.file)
1297                 io_req->fds[0] = dev->cow.fd;
1298         else
1299                 io_req->fds[0] = dev->fd;
1300         io_req->error = 0;
1301         io_req->sectorsize = SECTOR_SIZE;
1302         io_req->fds[1] = dev->fd;
1303         io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT;
1304         io_req->offsets[0] = 0;
1305         io_req->offsets[1] = dev->cow.data_offset;
1306
1307         for (i = 0 ; i < desc_cnt; i++) {
1308                 io_req->io_desc[i].sector_mask = 0;
1309                 io_req->io_desc[i].cow_offset = -1;
1310         }
1311
1312         return io_req;
1313 }
1314
1315 static int ubd_submit_request(struct ubd *dev, struct request *req)
1316 {
1317         int segs = 0;
1318         struct io_thread_req *io_req;
1319         int ret;
1320         enum req_op op = req_op(req);
1321
1322         if (op == REQ_OP_FLUSH)
1323                 segs = 0;
1324         else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD)
1325                 segs = 1;
1326         else
1327                 segs = blk_rq_nr_phys_segments(req);
1328
1329         io_req = ubd_alloc_req(dev, req, segs);
1330         if (!io_req)
1331                 return -ENOMEM;
1332
1333         io_req->desc_cnt = segs;
1334         if (segs)
1335                 ubd_map_req(dev, io_req, req);
1336
1337         ret = os_write_file(thread_fd, &io_req, sizeof(io_req));
1338         if (ret != sizeof(io_req)) {
1339                 if (ret != -EAGAIN)
1340                         pr_err("write to io thread failed: %d\n", -ret);
1341                 kfree(io_req);
1342         }
1343         return ret;
1344 }
1345
1346 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
1347                                  const struct blk_mq_queue_data *bd)
1348 {
1349         struct ubd *ubd_dev = hctx->queue->queuedata;
1350         struct request *req = bd->rq;
1351         int ret = 0, res = BLK_STS_OK;
1352
1353         blk_mq_start_request(req);
1354
1355         spin_lock_irq(&ubd_dev->lock);
1356
1357         switch (req_op(req)) {
1358         case REQ_OP_FLUSH:
1359         case REQ_OP_READ:
1360         case REQ_OP_WRITE:
1361         case REQ_OP_DISCARD:
1362         case REQ_OP_WRITE_ZEROES:
1363                 ret = ubd_submit_request(ubd_dev, req);
1364                 break;
1365         default:
1366                 WARN_ON_ONCE(1);
1367                 res = BLK_STS_NOTSUPP;
1368         }
1369
1370         spin_unlock_irq(&ubd_dev->lock);
1371
1372         if (ret < 0) {
1373                 if (ret == -ENOMEM)
1374                         res = BLK_STS_RESOURCE;
1375                 else
1376                         res = BLK_STS_DEV_RESOURCE;
1377         }
1378
1379         return res;
1380 }
1381
1382 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1383 {
1384         struct ubd *ubd_dev = bdev->bd_disk->private_data;
1385
1386         geo->heads = 128;
1387         geo->sectors = 32;
1388         geo->cylinders = ubd_dev->size / (128 * 32 * 512);
1389         return 0;
1390 }
1391
1392 static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode,
1393                      unsigned int cmd, unsigned long arg)
1394 {
1395         struct ubd *ubd_dev = bdev->bd_disk->private_data;
1396         u16 ubd_id[ATA_ID_WORDS];
1397
1398         switch (cmd) {
1399                 struct cdrom_volctrl volume;
1400         case HDIO_GET_IDENTITY:
1401                 memset(&ubd_id, 0, ATA_ID_WORDS * 2);
1402                 ubd_id[ATA_ID_CYLS]     = ubd_dev->size / (128 * 32 * 512);
1403                 ubd_id[ATA_ID_HEADS]    = 128;
1404                 ubd_id[ATA_ID_SECTORS]  = 32;
1405                 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1406                                  sizeof(ubd_id)))
1407                         return -EFAULT;
1408                 return 0;
1409
1410         case CDROMVOLREAD:
1411                 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1412                         return -EFAULT;
1413                 volume.channel0 = 255;
1414                 volume.channel1 = 255;
1415                 volume.channel2 = 255;
1416                 volume.channel3 = 255;
1417                 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1418                         return -EFAULT;
1419                 return 0;
1420         }
1421         return -EINVAL;
1422 }
1423
1424 static int map_error(int error_code)
1425 {
1426         switch (error_code) {
1427         case 0:
1428                 return BLK_STS_OK;
1429         case ENOSYS:
1430         case EOPNOTSUPP:
1431                 return BLK_STS_NOTSUPP;
1432         case ENOSPC:
1433                 return BLK_STS_NOSPC;
1434         }
1435         return BLK_STS_IOERR;
1436 }
1437
1438 /*
1439  * Everything from here onwards *IS NOT PART OF THE KERNEL*
1440  *
1441  * The following functions are part of UML hypervisor code.
1442  * All functions from here onwards are executed as a helper
1443  * thread and are not allowed to execute any kernel functions.
1444  *
1445  * Any communication must occur strictly via shared memory and IPC.
1446  *
1447  * Do not add printks, locks, kernel memory operations, etc - it
1448  * will result in unpredictable behaviour and/or crashes.
1449  */
1450
1451 static int update_bitmap(struct io_thread_req *req, struct io_desc *segment)
1452 {
1453         int n;
1454
1455         if (segment->cow_offset == -1)
1456                 return map_error(0);
1457
1458         n = os_pwrite_file(req->fds[1], &segment->bitmap_words,
1459                           sizeof(segment->bitmap_words), segment->cow_offset);
1460         if (n != sizeof(segment->bitmap_words))
1461                 return map_error(-n);
1462
1463         return map_error(0);
1464 }
1465
1466 static void do_io(struct io_thread_req *req, struct io_desc *desc)
1467 {
1468         char *buf = NULL;
1469         unsigned long len;
1470         int n, nsectors, start, end, bit;
1471         __u64 off;
1472
1473         /* FLUSH is really a special case, we cannot "case" it with others */
1474
1475         if (req_op(req->req) == REQ_OP_FLUSH) {
1476                 /* fds[0] is always either the rw image or our cow file */
1477                 req->error = map_error(-os_sync_file(req->fds[0]));
1478                 return;
1479         }
1480
1481         nsectors = desc->length / req->sectorsize;
1482         start = 0;
1483         do {
1484                 bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask);
1485                 end = start;
1486                 while((end < nsectors) &&
1487                       (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit))
1488                         end++;
1489
1490                 off = req->offset + req->offsets[bit] +
1491                         start * req->sectorsize;
1492                 len = (end - start) * req->sectorsize;
1493                 if (desc->buffer != NULL)
1494                         buf = &desc->buffer[start * req->sectorsize];
1495
1496                 switch (req_op(req->req)) {
1497                 case REQ_OP_READ:
1498                         n = 0;
1499                         do {
1500                                 buf = &buf[n];
1501                                 len -= n;
1502                                 n = os_pread_file(req->fds[bit], buf, len, off);
1503                                 if (n < 0) {
1504                                         req->error = map_error(-n);
1505                                         return;
1506                                 }
1507                         } while((n < len) && (n != 0));
1508                         if (n < len) memset(&buf[n], 0, len - n);
1509                         break;
1510                 case REQ_OP_WRITE:
1511                         n = os_pwrite_file(req->fds[bit], buf, len, off);
1512                         if(n != len){
1513                                 req->error = map_error(-n);
1514                                 return;
1515                         }
1516                         break;
1517                 case REQ_OP_DISCARD:
1518                         n = os_falloc_punch(req->fds[bit], off, len);
1519                         if (n) {
1520                                 req->error = map_error(-n);
1521                                 return;
1522                         }
1523                         break;
1524                 case REQ_OP_WRITE_ZEROES:
1525                         n = os_falloc_zeroes(req->fds[bit], off, len);
1526                         if (n) {
1527                                 req->error = map_error(-n);
1528                                 return;
1529                         }
1530                         break;
1531                 default:
1532                         WARN_ON_ONCE(1);
1533                         req->error = BLK_STS_NOTSUPP;
1534                         return;
1535                 }
1536
1537                 start = end;
1538         } while(start < nsectors);
1539
1540         req->offset += len;
1541         req->error = update_bitmap(req, desc);
1542 }
1543
1544 /* Changed in start_io_thread, which is serialized by being called only
1545  * from ubd_init, which is an initcall.
1546  */
1547 int kernel_fd = -1;
1548
1549 /* Only changed by the io thread. XXX: currently unused. */
1550 static int io_count;
1551
1552 int io_thread(void *arg)
1553 {
1554         int n, count, written, res;
1555
1556         os_fix_helper_signals();
1557
1558         while(1){
1559                 n = bulk_req_safe_read(
1560                         kernel_fd,
1561                         io_req_buffer,
1562                         &io_remainder,
1563                         &io_remainder_size,
1564                         UBD_REQ_BUFFER_SIZE
1565                 );
1566                 if (n <= 0) {
1567                         if (n == -EAGAIN)
1568                                 ubd_read_poll(-1);
1569
1570                         continue;
1571                 }
1572
1573                 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
1574                         struct io_thread_req *req = (*io_req_buffer)[count];
1575                         int i;
1576
1577                         io_count++;
1578                         for (i = 0; !req->error && i < req->desc_cnt; i++)
1579                                 do_io(req, &(req->io_desc[i]));
1580
1581                 }
1582
1583                 written = 0;
1584
1585                 do {
1586                         res = os_write_file(kernel_fd,
1587                                             ((char *) io_req_buffer) + written,
1588                                             n - written);
1589                         if (res >= 0) {
1590                                 written += res;
1591                         }
1592                         if (written < n) {
1593                                 ubd_write_poll(-1);
1594                         }
1595                 } while (written < n);
1596         }
1597
1598         return 0;
1599 }