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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
51struct 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
59struct 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
73static struct io_thread_req * (*irq_req_buffer)[];
74static struct io_thread_req *irq_remainder;
75static int irq_remainder_size;
76
77static struct io_thread_req * (*io_req_buffer)[];
78static struct io_thread_req *io_remainder;
79static int io_remainder_size;
80
81
82
83static 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
94static 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
108static DEFINE_MUTEX(ubd_lock);
109static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
110
111static int ubd_open(struct block_device *bdev, fmode_t mode);
112static void ubd_release(struct gendisk *disk, fmode_t mode);
113static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
114 unsigned int cmd, unsigned long arg);
115static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
116
117#define MAX_DEV (16)
118
119static 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 */
129static 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
138static struct openflags global_openflags = OPEN_FLAGS;
139
140struct 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
153struct 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 */
197static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
198
199static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
200 const struct blk_mq_queue_data *bd);
201
202static 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
214static 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 */
237static 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
314break_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;
337out:
338 mutex_unlock(&ubd_lock);
339 return err;
340}
341
342static 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
387static 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. */
404static 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
410static 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. */
460static 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
493static 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. */
500static int io_pid = -1;
501
502static 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
510static 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, §or_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
543out:
544 return os_file_size(file, size_out);
545}
546
547static 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
558static 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
593static 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
624static 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, §orsize, &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
703static 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
729static 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
740static 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
812static 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
820static 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
832static DEVICE_ATTR_RO(serial);
833
834static struct attribute *ubd_attrs[] = {
835 &dev_attr_serial.attr,
836 NULL,
837};
838
839static umode_t ubd_attrs_are_visible(struct kobject *kobj,
840 struct attribute *a, int n)
841{
842 return a->mode;
843}
844
845static const struct attribute_group ubd_attr_group = {
846 .attrs = ubd_attrs,
847 .is_visible = ubd_attrs_are_visible,
848};
849
850static const struct attribute_group *ubd_attr_groups[] = {
851 &ubd_attr_group,
852 NULL,
853};
854
855static 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
878static const struct blk_mq_ops ubd_mq_ops = {
879 .queue_rq = ubd_queue_rq,
880};
881
882static 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
927out_cleanup_disk:
928 put_disk(disk);
929out_cleanup_tags:
930 blk_mq_free_tag_set(&ubd_dev->tag_set);
931out:
932 return err;
933}
934
935static 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
964out:
965 return ret;
966
967err_free:
968 kfree(str);
969 goto out;
970}
971
972static 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
1004static 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
1014static 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);
1040out:
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 */
1048static 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
1057static int __init ubd_mc_init(void)
1058{
1059 mconsole_register_dev(&ubd_mc);
1060 return 0;
1061}
1062
1063__initcall(ubd_mc_init);
1064
1065static 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 */
1080static struct platform_driver ubd_driver = {
1081 .driver = {
1082 .name = DRIVER_NAME,
1083 },
1084};
1085
1086static 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
1127late_initcall(ubd_init);
1128
1129static 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
1155device_initcall(ubd_driver_init);
1156
1157static int ubd_open(struct block_device *bdev, fmode_t mode)
1158{
1159 struct gendisk *disk = bdev->bd_disk;
1160 struct ubd *ubd_dev = disk->private_data;
1161 int err = 0;
1162
1163 mutex_lock(&ubd_mutex);
1164 if(ubd_dev->count == 0){
1165 err = ubd_open_dev(ubd_dev);
1166 if(err){
1167 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
1168 disk->disk_name, ubd_dev->file, -err);
1169 goto out;
1170 }
1171 }
1172 ubd_dev->count++;
1173 set_disk_ro(disk, !ubd_dev->openflags.w);
1174
1175 /* This should no more be needed. And it didn't work anyway to exclude
1176 * read-write remounting of filesystems.*/
1177 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){
1178 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
1179 err = -EROFS;
1180 }*/
1181out:
1182 mutex_unlock(&ubd_mutex);
1183 return err;
1184}
1185
1186static void ubd_release(struct gendisk *disk, fmode_t mode)
1187{
1188 struct ubd *ubd_dev = disk->private_data;
1189
1190 mutex_lock(&ubd_mutex);
1191 if(--ubd_dev->count == 0)
1192 ubd_close_dev(ubd_dev);
1193 mutex_unlock(&ubd_mutex);
1194}
1195
1196static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
1197 __u64 *cow_offset, unsigned long *bitmap,
1198 __u64 bitmap_offset, unsigned long *bitmap_words,
1199 __u64 bitmap_len)
1200{
1201 __u64 sector = io_offset >> SECTOR_SHIFT;
1202 int i, update_bitmap = 0;
1203
1204 for (i = 0; i < length >> SECTOR_SHIFT; i++) {
1205 if(cow_mask != NULL)
1206 ubd_set_bit(i, (unsigned char *) cow_mask);
1207 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1208 continue;
1209
1210 update_bitmap = 1;
1211 ubd_set_bit(sector + i, (unsigned char *) bitmap);
1212 }
1213
1214 if(!update_bitmap)
1215 return;
1216
1217 *cow_offset = sector / (sizeof(unsigned long) * 8);
1218
1219 /* This takes care of the case where we're exactly at the end of the
1220 * device, and *cow_offset + 1 is off the end. So, just back it up
1221 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1222 * for the original diagnosis.
1223 */
1224 if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
1225 sizeof(unsigned long)) - 1))
1226 (*cow_offset)--;
1227
1228 bitmap_words[0] = bitmap[*cow_offset];
1229 bitmap_words[1] = bitmap[*cow_offset + 1];
1230
1231 *cow_offset *= sizeof(unsigned long);
1232 *cow_offset += bitmap_offset;
1233}
1234
1235static void cowify_req(struct io_thread_req *req, struct io_desc *segment,
1236 unsigned long offset, unsigned long *bitmap,
1237 __u64 bitmap_offset, __u64 bitmap_len)
1238{
1239 __u64 sector = offset >> SECTOR_SHIFT;
1240 int i;
1241
1242 if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT)
1243 panic("Operation too long");
1244
1245 if (req_op(req->req) == REQ_OP_READ) {
1246 for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) {
1247 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1248 ubd_set_bit(i, (unsigned char *)
1249 &segment->sector_mask);
1250 }
1251 } else {
1252 cowify_bitmap(offset, segment->length, &segment->sector_mask,
1253 &segment->cow_offset, bitmap, bitmap_offset,
1254 segment->bitmap_words, bitmap_len);
1255 }
1256}
1257
1258static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req,
1259 struct request *req)
1260{
1261 struct bio_vec bvec;
1262 struct req_iterator iter;
1263 int i = 0;
1264 unsigned long byte_offset = io_req->offset;
1265 enum req_op op = req_op(req);
1266
1267 if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) {
1268 io_req->io_desc[0].buffer = NULL;
1269 io_req->io_desc[0].length = blk_rq_bytes(req);
1270 } else {
1271 rq_for_each_segment(bvec, req, iter) {
1272 BUG_ON(i >= io_req->desc_cnt);
1273
1274 io_req->io_desc[i].buffer = bvec_virt(&bvec);
1275 io_req->io_desc[i].length = bvec.bv_len;
1276 i++;
1277 }
1278 }
1279
1280 if (dev->cow.file) {
1281 for (i = 0; i < io_req->desc_cnt; i++) {
1282 cowify_req(io_req, &io_req->io_desc[i], byte_offset,
1283 dev->cow.bitmap, dev->cow.bitmap_offset,
1284 dev->cow.bitmap_len);
1285 byte_offset += io_req->io_desc[i].length;
1286 }
1287
1288 }
1289}
1290
1291static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req,
1292 int desc_cnt)
1293{
1294 struct io_thread_req *io_req;
1295 int i;
1296
1297 io_req = kmalloc(sizeof(*io_req) +
1298 (desc_cnt * sizeof(struct io_desc)),
1299 GFP_ATOMIC);
1300 if (!io_req)
1301 return NULL;
1302
1303 io_req->req = req;
1304 if (dev->cow.file)
1305 io_req->fds[0] = dev->cow.fd;
1306 else
1307 io_req->fds[0] = dev->fd;
1308 io_req->error = 0;
1309 io_req->sectorsize = SECTOR_SIZE;
1310 io_req->fds[1] = dev->fd;
1311 io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT;
1312 io_req->offsets[0] = 0;
1313 io_req->offsets[1] = dev->cow.data_offset;
1314
1315 for (i = 0 ; i < desc_cnt; i++) {
1316 io_req->io_desc[i].sector_mask = 0;
1317 io_req->io_desc[i].cow_offset = -1;
1318 }
1319
1320 return io_req;
1321}
1322
1323static int ubd_submit_request(struct ubd *dev, struct request *req)
1324{
1325 int segs = 0;
1326 struct io_thread_req *io_req;
1327 int ret;
1328 enum req_op op = req_op(req);
1329
1330 if (op == REQ_OP_FLUSH)
1331 segs = 0;
1332 else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD)
1333 segs = 1;
1334 else
1335 segs = blk_rq_nr_phys_segments(req);
1336
1337 io_req = ubd_alloc_req(dev, req, segs);
1338 if (!io_req)
1339 return -ENOMEM;
1340
1341 io_req->desc_cnt = segs;
1342 if (segs)
1343 ubd_map_req(dev, io_req, req);
1344
1345 ret = os_write_file(thread_fd, &io_req, sizeof(io_req));
1346 if (ret != sizeof(io_req)) {
1347 if (ret != -EAGAIN)
1348 pr_err("write to io thread failed: %d\n", -ret);
1349 kfree(io_req);
1350 }
1351 return ret;
1352}
1353
1354static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
1355 const struct blk_mq_queue_data *bd)
1356{
1357 struct ubd *ubd_dev = hctx->queue->queuedata;
1358 struct request *req = bd->rq;
1359 int ret = 0, res = BLK_STS_OK;
1360
1361 blk_mq_start_request(req);
1362
1363 spin_lock_irq(&ubd_dev->lock);
1364
1365 switch (req_op(req)) {
1366 case REQ_OP_FLUSH:
1367 case REQ_OP_READ:
1368 case REQ_OP_WRITE:
1369 case REQ_OP_DISCARD:
1370 case REQ_OP_WRITE_ZEROES:
1371 ret = ubd_submit_request(ubd_dev, req);
1372 break;
1373 default:
1374 WARN_ON_ONCE(1);
1375 res = BLK_STS_NOTSUPP;
1376 }
1377
1378 spin_unlock_irq(&ubd_dev->lock);
1379
1380 if (ret < 0) {
1381 if (ret == -ENOMEM)
1382 res = BLK_STS_RESOURCE;
1383 else
1384 res = BLK_STS_DEV_RESOURCE;
1385 }
1386
1387 return res;
1388}
1389
1390static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1391{
1392 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1393
1394 geo->heads = 128;
1395 geo->sectors = 32;
1396 geo->cylinders = ubd_dev->size / (128 * 32 * 512);
1397 return 0;
1398}
1399
1400static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
1401 unsigned int cmd, unsigned long arg)
1402{
1403 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1404 u16 ubd_id[ATA_ID_WORDS];
1405
1406 switch (cmd) {
1407 struct cdrom_volctrl volume;
1408 case HDIO_GET_IDENTITY:
1409 memset(&ubd_id, 0, ATA_ID_WORDS * 2);
1410 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512);
1411 ubd_id[ATA_ID_HEADS] = 128;
1412 ubd_id[ATA_ID_SECTORS] = 32;
1413 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1414 sizeof(ubd_id)))
1415 return -EFAULT;
1416 return 0;
1417
1418 case CDROMVOLREAD:
1419 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1420 return -EFAULT;
1421 volume.channel0 = 255;
1422 volume.channel1 = 255;
1423 volume.channel2 = 255;
1424 volume.channel3 = 255;
1425 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1426 return -EFAULT;
1427 return 0;
1428 }
1429 return -EINVAL;
1430}
1431
1432static int map_error(int error_code)
1433{
1434 switch (error_code) {
1435 case 0:
1436 return BLK_STS_OK;
1437 case ENOSYS:
1438 case EOPNOTSUPP:
1439 return BLK_STS_NOTSUPP;
1440 case ENOSPC:
1441 return BLK_STS_NOSPC;
1442 }
1443 return BLK_STS_IOERR;
1444}
1445
1446/*
1447 * Everything from here onwards *IS NOT PART OF THE KERNEL*
1448 *
1449 * The following functions are part of UML hypervisor code.
1450 * All functions from here onwards are executed as a helper
1451 * thread and are not allowed to execute any kernel functions.
1452 *
1453 * Any communication must occur strictly via shared memory and IPC.
1454 *
1455 * Do not add printks, locks, kernel memory operations, etc - it
1456 * will result in unpredictable behaviour and/or crashes.
1457 */
1458
1459static int update_bitmap(struct io_thread_req *req, struct io_desc *segment)
1460{
1461 int n;
1462
1463 if (segment->cow_offset == -1)
1464 return map_error(0);
1465
1466 n = os_pwrite_file(req->fds[1], &segment->bitmap_words,
1467 sizeof(segment->bitmap_words), segment->cow_offset);
1468 if (n != sizeof(segment->bitmap_words))
1469 return map_error(-n);
1470
1471 return map_error(0);
1472}
1473
1474static void do_io(struct io_thread_req *req, struct io_desc *desc)
1475{
1476 char *buf = NULL;
1477 unsigned long len;
1478 int n, nsectors, start, end, bit;
1479 __u64 off;
1480
1481 /* FLUSH is really a special case, we cannot "case" it with others */
1482
1483 if (req_op(req->req) == REQ_OP_FLUSH) {
1484 /* fds[0] is always either the rw image or our cow file */
1485 req->error = map_error(-os_sync_file(req->fds[0]));
1486 return;
1487 }
1488
1489 nsectors = desc->length / req->sectorsize;
1490 start = 0;
1491 do {
1492 bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask);
1493 end = start;
1494 while((end < nsectors) &&
1495 (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit))
1496 end++;
1497
1498 off = req->offset + req->offsets[bit] +
1499 start * req->sectorsize;
1500 len = (end - start) * req->sectorsize;
1501 if (desc->buffer != NULL)
1502 buf = &desc->buffer[start * req->sectorsize];
1503
1504 switch (req_op(req->req)) {
1505 case REQ_OP_READ:
1506 n = 0;
1507 do {
1508 buf = &buf[n];
1509 len -= n;
1510 n = os_pread_file(req->fds[bit], buf, len, off);
1511 if (n < 0) {
1512 req->error = map_error(-n);
1513 return;
1514 }
1515 } while((n < len) && (n != 0));
1516 if (n < len) memset(&buf[n], 0, len - n);
1517 break;
1518 case REQ_OP_WRITE:
1519 n = os_pwrite_file(req->fds[bit], buf, len, off);
1520 if(n != len){
1521 req->error = map_error(-n);
1522 return;
1523 }
1524 break;
1525 case REQ_OP_DISCARD:
1526 n = os_falloc_punch(req->fds[bit], off, len);
1527 if (n) {
1528 req->error = map_error(-n);
1529 return;
1530 }
1531 break;
1532 case REQ_OP_WRITE_ZEROES:
1533 n = os_falloc_zeroes(req->fds[bit], off, len);
1534 if (n) {
1535 req->error = map_error(-n);
1536 return;
1537 }
1538 break;
1539 default:
1540 WARN_ON_ONCE(1);
1541 req->error = BLK_STS_NOTSUPP;
1542 return;
1543 }
1544
1545 start = end;
1546 } while(start < nsectors);
1547
1548 req->offset += len;
1549 req->error = update_bitmap(req, desc);
1550}
1551
1552/* Changed in start_io_thread, which is serialized by being called only
1553 * from ubd_init, which is an initcall.
1554 */
1555int kernel_fd = -1;
1556
1557/* Only changed by the io thread. XXX: currently unused. */
1558static int io_count;
1559
1560int io_thread(void *arg)
1561{
1562 int n, count, written, res;
1563
1564 os_fix_helper_signals();
1565
1566 while(1){
1567 n = bulk_req_safe_read(
1568 kernel_fd,
1569 io_req_buffer,
1570 &io_remainder,
1571 &io_remainder_size,
1572 UBD_REQ_BUFFER_SIZE
1573 );
1574 if (n <= 0) {
1575 if (n == -EAGAIN)
1576 ubd_read_poll(-1);
1577
1578 continue;
1579 }
1580
1581 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
1582 struct io_thread_req *req = (*io_req_buffer)[count];
1583 int i;
1584
1585 io_count++;
1586 for (i = 0; !req->error && i < req->desc_cnt; i++)
1587 do_io(req, &(req->io_desc[i]));
1588
1589 }
1590
1591 written = 0;
1592
1593 do {
1594 res = os_write_file(kernel_fd,
1595 ((char *) io_req_buffer) + written,
1596 n - written);
1597 if (res >= 0) {
1598 written += res;
1599 }
1600 if (written < n) {
1601 ubd_write_poll(-1);
1602 }
1603 } while (written < n);
1604 }
1605
1606 return 0;
1607}
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/cdrom.h>
31#include <linux/proc_fs.h>
32#include <linux/seq_file.h>
33#include <linux/ctype.h>
34#include <linux/slab.h>
35#include <linux/vmalloc.h>
36#include <linux/platform_device.h>
37#include <linux/scatterlist.h>
38#include <asm/tlbflush.h>
39#include <kern_util.h>
40#include "mconsole_kern.h"
41#include <init.h>
42#include <irq_kern.h>
43#include "ubd.h"
44#include <os.h>
45#include "cow.h"
46
47/* Max request size is determined by sector mask - 32K */
48#define UBD_MAX_REQUEST (8 * sizeof(long))
49
50struct io_thread_req {
51 struct request *req;
52 int fds[2];
53 unsigned long offsets[2];
54 unsigned long long offset;
55 unsigned long length;
56 char *buffer;
57 int sectorsize;
58 unsigned long sector_mask;
59 unsigned long long cow_offset;
60 unsigned long bitmap_words[2];
61 int error;
62};
63
64
65static struct io_thread_req * (*irq_req_buffer)[];
66static struct io_thread_req *irq_remainder;
67static int irq_remainder_size;
68
69static struct io_thread_req * (*io_req_buffer)[];
70static struct io_thread_req *io_remainder;
71static int io_remainder_size;
72
73
74
75static inline int ubd_test_bit(__u64 bit, unsigned char *data)
76{
77 __u64 n;
78 int bits, off;
79
80 bits = sizeof(data[0]) * 8;
81 n = bit / bits;
82 off = bit % bits;
83 return (data[n] & (1 << off)) != 0;
84}
85
86static inline void ubd_set_bit(__u64 bit, unsigned char *data)
87{
88 __u64 n;
89 int bits, off;
90
91 bits = sizeof(data[0]) * 8;
92 n = bit / bits;
93 off = bit % bits;
94 data[n] |= (1 << off);
95}
96/*End stuff from ubd_user.h*/
97
98#define DRIVER_NAME "uml-blkdev"
99
100static DEFINE_MUTEX(ubd_lock);
101static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
102
103static int ubd_open(struct block_device *bdev, fmode_t mode);
104static void ubd_release(struct gendisk *disk, fmode_t mode);
105static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
106 unsigned int cmd, unsigned long arg);
107static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
108
109#define MAX_DEV (16)
110
111static const struct block_device_operations ubd_blops = {
112 .owner = THIS_MODULE,
113 .open = ubd_open,
114 .release = ubd_release,
115 .ioctl = ubd_ioctl,
116 .getgeo = ubd_getgeo,
117};
118
119/* Protected by ubd_lock */
120static int fake_major = UBD_MAJOR;
121static struct gendisk *ubd_gendisk[MAX_DEV];
122static struct gendisk *fake_gendisk[MAX_DEV];
123
124#ifdef CONFIG_BLK_DEV_UBD_SYNC
125#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
126 .cl = 1 })
127#else
128#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
129 .cl = 1 })
130#endif
131static struct openflags global_openflags = OPEN_FLAGS;
132
133struct cow {
134 /* backing file name */
135 char *file;
136 /* backing file fd */
137 int fd;
138 unsigned long *bitmap;
139 unsigned long bitmap_len;
140 int bitmap_offset;
141 int data_offset;
142};
143
144#define MAX_SG 64
145
146struct ubd {
147 /* name (and fd, below) of the file opened for writing, either the
148 * backing or the cow file. */
149 char *file;
150 int count;
151 int fd;
152 __u64 size;
153 struct openflags boot_openflags;
154 struct openflags openflags;
155 unsigned shared:1;
156 unsigned no_cow:1;
157 unsigned no_trim:1;
158 struct cow cow;
159 struct platform_device pdev;
160 struct request_queue *queue;
161 struct blk_mq_tag_set tag_set;
162 spinlock_t lock;
163};
164
165#define DEFAULT_COW { \
166 .file = NULL, \
167 .fd = -1, \
168 .bitmap = NULL, \
169 .bitmap_offset = 0, \
170 .data_offset = 0, \
171}
172
173#define DEFAULT_UBD { \
174 .file = NULL, \
175 .count = 0, \
176 .fd = -1, \
177 .size = -1, \
178 .boot_openflags = OPEN_FLAGS, \
179 .openflags = OPEN_FLAGS, \
180 .no_cow = 0, \
181 .no_trim = 0, \
182 .shared = 0, \
183 .cow = DEFAULT_COW, \
184 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
185}
186
187/* Protected by ubd_lock */
188static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
189
190/* Only changed by fake_ide_setup which is a setup */
191static int fake_ide = 0;
192static struct proc_dir_entry *proc_ide_root = NULL;
193static struct proc_dir_entry *proc_ide = NULL;
194
195static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
196 const struct blk_mq_queue_data *bd);
197
198static void make_proc_ide(void)
199{
200 proc_ide_root = proc_mkdir("ide", NULL);
201 proc_ide = proc_mkdir("ide0", proc_ide_root);
202}
203
204static int fake_ide_media_proc_show(struct seq_file *m, void *v)
205{
206 seq_puts(m, "disk\n");
207 return 0;
208}
209
210static void make_ide_entries(const char *dev_name)
211{
212 struct proc_dir_entry *dir, *ent;
213 char name[64];
214
215 if(proc_ide_root == NULL) make_proc_ide();
216
217 dir = proc_mkdir(dev_name, proc_ide);
218 if(!dir) return;
219
220 ent = proc_create_single("media", S_IRUGO, dir,
221 fake_ide_media_proc_show);
222 if(!ent) return;
223 snprintf(name, sizeof(name), "ide0/%s", dev_name);
224 proc_symlink(dev_name, proc_ide_root, name);
225}
226
227static int fake_ide_setup(char *str)
228{
229 fake_ide = 1;
230 return 1;
231}
232
233__setup("fake_ide", fake_ide_setup);
234
235__uml_help(fake_ide_setup,
236"fake_ide\n"
237" Create ide0 entries that map onto ubd devices.\n\n"
238);
239
240static int parse_unit(char **ptr)
241{
242 char *str = *ptr, *end;
243 int n = -1;
244
245 if(isdigit(*str)) {
246 n = simple_strtoul(str, &end, 0);
247 if(end == str)
248 return -1;
249 *ptr = end;
250 }
251 else if (('a' <= *str) && (*str <= 'z')) {
252 n = *str - 'a';
253 str++;
254 *ptr = str;
255 }
256 return n;
257}
258
259/* If *index_out == -1 at exit, the passed option was a general one;
260 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
261 * should not be freed on exit.
262 */
263static int ubd_setup_common(char *str, int *index_out, char **error_out)
264{
265 struct ubd *ubd_dev;
266 struct openflags flags = global_openflags;
267 char *backing_file;
268 int n, err = 0, i;
269
270 if(index_out) *index_out = -1;
271 n = *str;
272 if(n == '='){
273 char *end;
274 int major;
275
276 str++;
277 if(!strcmp(str, "sync")){
278 global_openflags = of_sync(global_openflags);
279 return err;
280 }
281
282 err = -EINVAL;
283 major = simple_strtoul(str, &end, 0);
284 if((*end != '\0') || (end == str)){
285 *error_out = "Didn't parse major number";
286 return err;
287 }
288
289 mutex_lock(&ubd_lock);
290 if (fake_major != UBD_MAJOR) {
291 *error_out = "Can't assign a fake major twice";
292 goto out1;
293 }
294
295 fake_major = major;
296
297 printk(KERN_INFO "Setting extra ubd major number to %d\n",
298 major);
299 err = 0;
300 out1:
301 mutex_unlock(&ubd_lock);
302 return err;
303 }
304
305 n = parse_unit(&str);
306 if(n < 0){
307 *error_out = "Couldn't parse device number";
308 return -EINVAL;
309 }
310 if(n >= MAX_DEV){
311 *error_out = "Device number out of range";
312 return 1;
313 }
314
315 err = -EBUSY;
316 mutex_lock(&ubd_lock);
317
318 ubd_dev = &ubd_devs[n];
319 if(ubd_dev->file != NULL){
320 *error_out = "Device is already configured";
321 goto out;
322 }
323
324 if (index_out)
325 *index_out = n;
326
327 err = -EINVAL;
328 for (i = 0; i < sizeof("rscdt="); i++) {
329 switch (*str) {
330 case 'r':
331 flags.w = 0;
332 break;
333 case 's':
334 flags.s = 1;
335 break;
336 case 'd':
337 ubd_dev->no_cow = 1;
338 break;
339 case 'c':
340 ubd_dev->shared = 1;
341 break;
342 case 't':
343 ubd_dev->no_trim = 1;
344 break;
345 case '=':
346 str++;
347 goto break_loop;
348 default:
349 *error_out = "Expected '=' or flag letter "
350 "(r, s, c, t or d)";
351 goto out;
352 }
353 str++;
354 }
355
356 if (*str == '=')
357 *error_out = "Too many flags specified";
358 else
359 *error_out = "Missing '='";
360 goto out;
361
362break_loop:
363 backing_file = strchr(str, ',');
364
365 if (backing_file == NULL)
366 backing_file = strchr(str, ':');
367
368 if(backing_file != NULL){
369 if(ubd_dev->no_cow){
370 *error_out = "Can't specify both 'd' and a cow file";
371 goto out;
372 }
373 else {
374 *backing_file = '\0';
375 backing_file++;
376 }
377 }
378 err = 0;
379 ubd_dev->file = str;
380 ubd_dev->cow.file = backing_file;
381 ubd_dev->boot_openflags = flags;
382out:
383 mutex_unlock(&ubd_lock);
384 return err;
385}
386
387static int ubd_setup(char *str)
388{
389 char *error;
390 int err;
391
392 err = ubd_setup_common(str, NULL, &error);
393 if(err)
394 printk(KERN_ERR "Failed to initialize device with \"%s\" : "
395 "%s\n", str, error);
396 return 1;
397}
398
399__setup("ubd", ubd_setup);
400__uml_help(ubd_setup,
401"ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
402" This is used to associate a device with a file in the underlying\n"
403" filesystem. When specifying two filenames, the first one is the\n"
404" COW name and the second is the backing file name. As separator you can\n"
405" use either a ':' or a ',': the first one allows writing things like;\n"
406" ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
407" while with a ',' the shell would not expand the 2nd '~'.\n"
408" When using only one filename, UML will detect whether to treat it like\n"
409" a COW file or a backing file. To override this detection, add the 'd'\n"
410" flag:\n"
411" ubd0d=BackingFile\n"
412" Usually, there is a filesystem in the file, but \n"
413" that's not required. Swap devices containing swap files can be\n"
414" specified like this. Also, a file which doesn't contain a\n"
415" filesystem can have its contents read in the virtual \n"
416" machine by running 'dd' on the device. <n> must be in the range\n"
417" 0 to 7. Appending an 'r' to the number will cause that device\n"
418" to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
419" an 's' will cause data to be written to disk on the host immediately.\n"
420" 'c' will cause the device to be treated as being shared between multiple\n"
421" UMLs and file locking will be turned off - this is appropriate for a\n"
422" cluster filesystem and inappropriate at almost all other times.\n\n"
423" 't' will disable trim/discard support on the device (enabled by default).\n\n"
424);
425
426static int udb_setup(char *str)
427{
428 printk("udb%s specified on command line is almost certainly a ubd -> "
429 "udb TYPO\n", str);
430 return 1;
431}
432
433__setup("udb", udb_setup);
434__uml_help(udb_setup,
435"udb\n"
436" This option is here solely to catch ubd -> udb typos, which can be\n"
437" to impossible to catch visually unless you specifically look for\n"
438" them. The only result of any option starting with 'udb' is an error\n"
439" in the boot output.\n\n"
440);
441
442/* Only changed by ubd_init, which is an initcall. */
443static int thread_fd = -1;
444
445/* Function to read several request pointers at a time
446* handling fractional reads if (and as) needed
447*/
448
449static int bulk_req_safe_read(
450 int fd,
451 struct io_thread_req * (*request_buffer)[],
452 struct io_thread_req **remainder,
453 int *remainder_size,
454 int max_recs
455 )
456{
457 int n = 0;
458 int res = 0;
459
460 if (*remainder_size > 0) {
461 memmove(
462 (char *) request_buffer,
463 (char *) remainder, *remainder_size
464 );
465 n = *remainder_size;
466 }
467
468 res = os_read_file(
469 fd,
470 ((char *) request_buffer) + *remainder_size,
471 sizeof(struct io_thread_req *)*max_recs
472 - *remainder_size
473 );
474 if (res > 0) {
475 n += res;
476 if ((n % sizeof(struct io_thread_req *)) > 0) {
477 /*
478 * Read somehow returned not a multiple of dword
479 * theoretically possible, but never observed in the
480 * wild, so read routine must be able to handle it
481 */
482 *remainder_size = n % sizeof(struct io_thread_req *);
483 WARN(*remainder_size > 0, "UBD IPC read returned a partial result");
484 memmove(
485 remainder,
486 ((char *) request_buffer) +
487 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *),
488 *remainder_size
489 );
490 n = n - *remainder_size;
491 }
492 } else {
493 n = res;
494 }
495 return n;
496}
497
498/* Called without dev->lock held, and only in interrupt context. */
499static void ubd_handler(void)
500{
501 int n;
502 int count;
503
504 while(1){
505 n = bulk_req_safe_read(
506 thread_fd,
507 irq_req_buffer,
508 &irq_remainder,
509 &irq_remainder_size,
510 UBD_REQ_BUFFER_SIZE
511 );
512 if (n < 0) {
513 if(n == -EAGAIN)
514 break;
515 printk(KERN_ERR "spurious interrupt in ubd_handler, "
516 "err = %d\n", -n);
517 return;
518 }
519 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
520 struct io_thread_req *io_req = (*irq_req_buffer)[count];
521
522 if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
523 blk_queue_max_discard_sectors(io_req->req->q, 0);
524 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
525 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q);
526 }
527 if ((io_req->error) || (io_req->buffer == NULL))
528 blk_mq_end_request(io_req->req, io_req->error);
529 else {
530 if (!blk_update_request(io_req->req, io_req->error, io_req->length))
531 __blk_mq_end_request(io_req->req, io_req->error);
532 }
533 kfree(io_req);
534 }
535 }
536}
537
538static irqreturn_t ubd_intr(int irq, void *dev)
539{
540 ubd_handler();
541 return IRQ_HANDLED;
542}
543
544/* Only changed by ubd_init, which is an initcall. */
545static int io_pid = -1;
546
547static void kill_io_thread(void)
548{
549 if(io_pid != -1)
550 os_kill_process(io_pid, 1);
551}
552
553__uml_exitcall(kill_io_thread);
554
555static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
556{
557 char *file;
558 int fd;
559 int err;
560
561 __u32 version;
562 __u32 align;
563 char *backing_file;
564 time_t mtime;
565 unsigned long long size;
566 int sector_size;
567 int bitmap_offset;
568
569 if (ubd_dev->file && ubd_dev->cow.file) {
570 file = ubd_dev->cow.file;
571
572 goto out;
573 }
574
575 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0);
576 if (fd < 0)
577 return fd;
578
579 err = read_cow_header(file_reader, &fd, &version, &backing_file, \
580 &mtime, &size, §or_size, &align, &bitmap_offset);
581 os_close_file(fd);
582
583 if(err == -EINVAL)
584 file = ubd_dev->file;
585 else
586 file = backing_file;
587
588out:
589 return os_file_size(file, size_out);
590}
591
592static int read_cow_bitmap(int fd, void *buf, int offset, int len)
593{
594 int err;
595
596 err = os_pread_file(fd, buf, len, offset);
597 if (err < 0)
598 return err;
599
600 return 0;
601}
602
603static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
604{
605 unsigned long modtime;
606 unsigned long long actual;
607 int err;
608
609 err = os_file_modtime(file, &modtime);
610 if (err < 0) {
611 printk(KERN_ERR "Failed to get modification time of backing "
612 "file \"%s\", err = %d\n", file, -err);
613 return err;
614 }
615
616 err = os_file_size(file, &actual);
617 if (err < 0) {
618 printk(KERN_ERR "Failed to get size of backing file \"%s\", "
619 "err = %d\n", file, -err);
620 return err;
621 }
622
623 if (actual != size) {
624 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
625 * the typecast.*/
626 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header "
627 "vs backing file\n", (unsigned long long) size, actual);
628 return -EINVAL;
629 }
630 if (modtime != mtime) {
631 printk(KERN_ERR "mtime mismatch (%ld vs %ld) of COW header vs "
632 "backing file\n", mtime, modtime);
633 return -EINVAL;
634 }
635 return 0;
636}
637
638static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
639{
640 struct uml_stat buf1, buf2;
641 int err;
642
643 if (from_cmdline == NULL)
644 return 0;
645 if (!strcmp(from_cmdline, from_cow))
646 return 0;
647
648 err = os_stat_file(from_cmdline, &buf1);
649 if (err < 0) {
650 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline,
651 -err);
652 return 0;
653 }
654 err = os_stat_file(from_cow, &buf2);
655 if (err < 0) {
656 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow,
657 -err);
658 return 1;
659 }
660 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
661 return 0;
662
663 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, "
664 "\"%s\" specified in COW header of \"%s\"\n",
665 from_cmdline, from_cow, cow);
666 return 1;
667}
668
669static int open_ubd_file(char *file, struct openflags *openflags, int shared,
670 char **backing_file_out, int *bitmap_offset_out,
671 unsigned long *bitmap_len_out, int *data_offset_out,
672 int *create_cow_out)
673{
674 time_t mtime;
675 unsigned long long size;
676 __u32 version, align;
677 char *backing_file;
678 int fd, err, sectorsize, asked_switch, mode = 0644;
679
680 fd = os_open_file(file, *openflags, mode);
681 if (fd < 0) {
682 if ((fd == -ENOENT) && (create_cow_out != NULL))
683 *create_cow_out = 1;
684 if (!openflags->w ||
685 ((fd != -EROFS) && (fd != -EACCES)))
686 return fd;
687 openflags->w = 0;
688 fd = os_open_file(file, *openflags, mode);
689 if (fd < 0)
690 return fd;
691 }
692
693 if (shared)
694 printk(KERN_INFO "Not locking \"%s\" on the host\n", file);
695 else {
696 err = os_lock_file(fd, openflags->w);
697 if (err < 0) {
698 printk(KERN_ERR "Failed to lock '%s', err = %d\n",
699 file, -err);
700 goto out_close;
701 }
702 }
703
704 /* Successful return case! */
705 if (backing_file_out == NULL)
706 return fd;
707
708 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
709 &size, §orsize, &align, bitmap_offset_out);
710 if (err && (*backing_file_out != NULL)) {
711 printk(KERN_ERR "Failed to read COW header from COW file "
712 "\"%s\", errno = %d\n", file, -err);
713 goto out_close;
714 }
715 if (err)
716 return fd;
717
718 asked_switch = path_requires_switch(*backing_file_out, backing_file,
719 file);
720
721 /* Allow switching only if no mismatch. */
722 if (asked_switch && !backing_file_mismatch(*backing_file_out, size,
723 mtime)) {
724 printk(KERN_ERR "Switching backing file to '%s'\n",
725 *backing_file_out);
726 err = write_cow_header(file, fd, *backing_file_out,
727 sectorsize, align, &size);
728 if (err) {
729 printk(KERN_ERR "Switch failed, errno = %d\n", -err);
730 goto out_close;
731 }
732 } else {
733 *backing_file_out = backing_file;
734 err = backing_file_mismatch(*backing_file_out, size, mtime);
735 if (err)
736 goto out_close;
737 }
738
739 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
740 bitmap_len_out, data_offset_out);
741
742 return fd;
743 out_close:
744 os_close_file(fd);
745 return err;
746}
747
748static int create_cow_file(char *cow_file, char *backing_file,
749 struct openflags flags,
750 int sectorsize, int alignment, int *bitmap_offset_out,
751 unsigned long *bitmap_len_out, int *data_offset_out)
752{
753 int err, fd;
754
755 flags.c = 1;
756 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL);
757 if (fd < 0) {
758 err = fd;
759 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n",
760 cow_file, -err);
761 goto out;
762 }
763
764 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
765 bitmap_offset_out, bitmap_len_out,
766 data_offset_out);
767 if (!err)
768 return fd;
769 os_close_file(fd);
770 out:
771 return err;
772}
773
774static void ubd_close_dev(struct ubd *ubd_dev)
775{
776 os_close_file(ubd_dev->fd);
777 if(ubd_dev->cow.file == NULL)
778 return;
779
780 os_close_file(ubd_dev->cow.fd);
781 vfree(ubd_dev->cow.bitmap);
782 ubd_dev->cow.bitmap = NULL;
783}
784
785static int ubd_open_dev(struct ubd *ubd_dev)
786{
787 struct openflags flags;
788 char **back_ptr;
789 int err, create_cow, *create_ptr;
790 int fd;
791
792 ubd_dev->openflags = ubd_dev->boot_openflags;
793 create_cow = 0;
794 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
795 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;
796
797 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
798 back_ptr, &ubd_dev->cow.bitmap_offset,
799 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
800 create_ptr);
801
802 if((fd == -ENOENT) && create_cow){
803 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
804 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE,
805 &ubd_dev->cow.bitmap_offset,
806 &ubd_dev->cow.bitmap_len,
807 &ubd_dev->cow.data_offset);
808 if(fd >= 0){
809 printk(KERN_INFO "Creating \"%s\" as COW file for "
810 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
811 }
812 }
813
814 if(fd < 0){
815 printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
816 -fd);
817 return fd;
818 }
819 ubd_dev->fd = fd;
820
821 if(ubd_dev->cow.file != NULL){
822 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long));
823
824 err = -ENOMEM;
825 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
826 if(ubd_dev->cow.bitmap == NULL){
827 printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
828 goto error;
829 }
830 flush_tlb_kernel_vm();
831
832 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
833 ubd_dev->cow.bitmap_offset,
834 ubd_dev->cow.bitmap_len);
835 if(err < 0)
836 goto error;
837
838 flags = ubd_dev->openflags;
839 flags.w = 0;
840 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
841 NULL, NULL, NULL, NULL);
842 if(err < 0) goto error;
843 ubd_dev->cow.fd = err;
844 }
845 if (ubd_dev->no_trim == 0) {
846 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
847 ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE;
848 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
849 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
850 blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue);
851 }
852 blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
853 return 0;
854 error:
855 os_close_file(ubd_dev->fd);
856 return err;
857}
858
859static void ubd_device_release(struct device *dev)
860{
861 struct ubd *ubd_dev = dev_get_drvdata(dev);
862
863 blk_cleanup_queue(ubd_dev->queue);
864 blk_mq_free_tag_set(&ubd_dev->tag_set);
865 *ubd_dev = ((struct ubd) DEFAULT_UBD);
866}
867
868static int ubd_disk_register(int major, u64 size, int unit,
869 struct gendisk **disk_out)
870{
871 struct device *parent = NULL;
872 struct gendisk *disk;
873
874 disk = alloc_disk(1 << UBD_SHIFT);
875 if(disk == NULL)
876 return -ENOMEM;
877
878 disk->major = major;
879 disk->first_minor = unit << UBD_SHIFT;
880 disk->fops = &ubd_blops;
881 set_capacity(disk, size / 512);
882 if (major == UBD_MAJOR)
883 sprintf(disk->disk_name, "ubd%c", 'a' + unit);
884 else
885 sprintf(disk->disk_name, "ubd_fake%d", unit);
886
887 /* sysfs register (not for ide fake devices) */
888 if (major == UBD_MAJOR) {
889 ubd_devs[unit].pdev.id = unit;
890 ubd_devs[unit].pdev.name = DRIVER_NAME;
891 ubd_devs[unit].pdev.dev.release = ubd_device_release;
892 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
893 platform_device_register(&ubd_devs[unit].pdev);
894 parent = &ubd_devs[unit].pdev.dev;
895 }
896
897 disk->private_data = &ubd_devs[unit];
898 disk->queue = ubd_devs[unit].queue;
899 device_add_disk(parent, disk, NULL);
900
901 *disk_out = disk;
902 return 0;
903}
904
905#define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
906
907static const struct blk_mq_ops ubd_mq_ops = {
908 .queue_rq = ubd_queue_rq,
909};
910
911static int ubd_add(int n, char **error_out)
912{
913 struct ubd *ubd_dev = &ubd_devs[n];
914 int err = 0;
915
916 if(ubd_dev->file == NULL)
917 goto out;
918
919 err = ubd_file_size(ubd_dev, &ubd_dev->size);
920 if(err < 0){
921 *error_out = "Couldn't determine size of device's file";
922 goto out;
923 }
924
925 ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
926
927 ubd_dev->tag_set.ops = &ubd_mq_ops;
928 ubd_dev->tag_set.queue_depth = 64;
929 ubd_dev->tag_set.numa_node = NUMA_NO_NODE;
930 ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
931 ubd_dev->tag_set.driver_data = ubd_dev;
932 ubd_dev->tag_set.nr_hw_queues = 1;
933
934 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set);
935 if (err)
936 goto out;
937
938 ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set);
939 if (IS_ERR(ubd_dev->queue)) {
940 err = PTR_ERR(ubd_dev->queue);
941 goto out_cleanup_tags;
942 }
943
944 ubd_dev->queue->queuedata = ubd_dev;
945 blk_queue_write_cache(ubd_dev->queue, true, false);
946
947 blk_queue_max_segments(ubd_dev->queue, MAX_SG);
948 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
949 if(err){
950 *error_out = "Failed to register device";
951 goto out_cleanup_tags;
952 }
953
954 if (fake_major != UBD_MAJOR)
955 ubd_disk_register(fake_major, ubd_dev->size, n,
956 &fake_gendisk[n]);
957
958 /*
959 * Perhaps this should also be under the "if (fake_major)" above
960 * using the fake_disk->disk_name
961 */
962 if (fake_ide)
963 make_ide_entries(ubd_gendisk[n]->disk_name);
964
965 err = 0;
966out:
967 return err;
968
969out_cleanup_tags:
970 blk_mq_free_tag_set(&ubd_dev->tag_set);
971 if (!(IS_ERR(ubd_dev->queue)))
972 blk_cleanup_queue(ubd_dev->queue);
973 goto out;
974}
975
976static int ubd_config(char *str, char **error_out)
977{
978 int n, ret;
979
980 /* This string is possibly broken up and stored, so it's only
981 * freed if ubd_setup_common fails, or if only general options
982 * were set.
983 */
984 str = kstrdup(str, GFP_KERNEL);
985 if (str == NULL) {
986 *error_out = "Failed to allocate memory";
987 return -ENOMEM;
988 }
989
990 ret = ubd_setup_common(str, &n, error_out);
991 if (ret)
992 goto err_free;
993
994 if (n == -1) {
995 ret = 0;
996 goto err_free;
997 }
998
999 mutex_lock(&ubd_lock);
1000 ret = ubd_add(n, error_out);
1001 if (ret)
1002 ubd_devs[n].file = NULL;
1003 mutex_unlock(&ubd_lock);
1004
1005out:
1006 return ret;
1007
1008err_free:
1009 kfree(str);
1010 goto out;
1011}
1012
1013static int ubd_get_config(char *name, char *str, int size, char **error_out)
1014{
1015 struct ubd *ubd_dev;
1016 int n, len = 0;
1017
1018 n = parse_unit(&name);
1019 if((n >= MAX_DEV) || (n < 0)){
1020 *error_out = "ubd_get_config : device number out of range";
1021 return -1;
1022 }
1023
1024 ubd_dev = &ubd_devs[n];
1025 mutex_lock(&ubd_lock);
1026
1027 if(ubd_dev->file == NULL){
1028 CONFIG_CHUNK(str, size, len, "", 1);
1029 goto out;
1030 }
1031
1032 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0);
1033
1034 if(ubd_dev->cow.file != NULL){
1035 CONFIG_CHUNK(str, size, len, ",", 0);
1036 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1);
1037 }
1038 else CONFIG_CHUNK(str, size, len, "", 1);
1039
1040 out:
1041 mutex_unlock(&ubd_lock);
1042 return len;
1043}
1044
1045static int ubd_id(char **str, int *start_out, int *end_out)
1046{
1047 int n;
1048
1049 n = parse_unit(str);
1050 *start_out = 0;
1051 *end_out = MAX_DEV - 1;
1052 return n;
1053}
1054
1055static int ubd_remove(int n, char **error_out)
1056{
1057 struct gendisk *disk = ubd_gendisk[n];
1058 struct ubd *ubd_dev;
1059 int err = -ENODEV;
1060
1061 mutex_lock(&ubd_lock);
1062
1063 ubd_dev = &ubd_devs[n];
1064
1065 if(ubd_dev->file == NULL)
1066 goto out;
1067
1068 /* you cannot remove a open disk */
1069 err = -EBUSY;
1070 if(ubd_dev->count > 0)
1071 goto out;
1072
1073 ubd_gendisk[n] = NULL;
1074 if(disk != NULL){
1075 del_gendisk(disk);
1076 put_disk(disk);
1077 }
1078
1079 if(fake_gendisk[n] != NULL){
1080 del_gendisk(fake_gendisk[n]);
1081 put_disk(fake_gendisk[n]);
1082 fake_gendisk[n] = NULL;
1083 }
1084
1085 err = 0;
1086 platform_device_unregister(&ubd_dev->pdev);
1087out:
1088 mutex_unlock(&ubd_lock);
1089 return err;
1090}
1091
1092/* All these are called by mconsole in process context and without
1093 * ubd-specific locks. The structure itself is const except for .list.
1094 */
1095static struct mc_device ubd_mc = {
1096 .list = LIST_HEAD_INIT(ubd_mc.list),
1097 .name = "ubd",
1098 .config = ubd_config,
1099 .get_config = ubd_get_config,
1100 .id = ubd_id,
1101 .remove = ubd_remove,
1102};
1103
1104static int __init ubd_mc_init(void)
1105{
1106 mconsole_register_dev(&ubd_mc);
1107 return 0;
1108}
1109
1110__initcall(ubd_mc_init);
1111
1112static int __init ubd0_init(void)
1113{
1114 struct ubd *ubd_dev = &ubd_devs[0];
1115
1116 mutex_lock(&ubd_lock);
1117 if(ubd_dev->file == NULL)
1118 ubd_dev->file = "root_fs";
1119 mutex_unlock(&ubd_lock);
1120
1121 return 0;
1122}
1123
1124__initcall(ubd0_init);
1125
1126/* Used in ubd_init, which is an initcall */
1127static struct platform_driver ubd_driver = {
1128 .driver = {
1129 .name = DRIVER_NAME,
1130 },
1131};
1132
1133static int __init ubd_init(void)
1134{
1135 char *error;
1136 int i, err;
1137
1138 if (register_blkdev(UBD_MAJOR, "ubd"))
1139 return -1;
1140
1141 if (fake_major != UBD_MAJOR) {
1142 char name[sizeof("ubd_nnn\0")];
1143
1144 snprintf(name, sizeof(name), "ubd_%d", fake_major);
1145 if (register_blkdev(fake_major, "ubd"))
1146 return -1;
1147 }
1148
1149 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1150 sizeof(struct io_thread_req *),
1151 GFP_KERNEL
1152 );
1153 irq_remainder = 0;
1154
1155 if (irq_req_buffer == NULL) {
1156 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1157 return -1;
1158 }
1159 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1160 sizeof(struct io_thread_req *),
1161 GFP_KERNEL
1162 );
1163
1164 io_remainder = 0;
1165
1166 if (io_req_buffer == NULL) {
1167 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1168 return -1;
1169 }
1170 platform_driver_register(&ubd_driver);
1171 mutex_lock(&ubd_lock);
1172 for (i = 0; i < MAX_DEV; i++){
1173 err = ubd_add(i, &error);
1174 if(err)
1175 printk(KERN_ERR "Failed to initialize ubd device %d :"
1176 "%s\n", i, error);
1177 }
1178 mutex_unlock(&ubd_lock);
1179 return 0;
1180}
1181
1182late_initcall(ubd_init);
1183
1184static int __init ubd_driver_init(void){
1185 unsigned long stack;
1186 int err;
1187
1188 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
1189 if(global_openflags.s){
1190 printk(KERN_INFO "ubd: Synchronous mode\n");
1191 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
1192 * enough. So use anyway the io thread. */
1193 }
1194 stack = alloc_stack(0, 0);
1195 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
1196 &thread_fd);
1197 if(io_pid < 0){
1198 printk(KERN_ERR
1199 "ubd : Failed to start I/O thread (errno = %d) - "
1200 "falling back to synchronous I/O\n", -io_pid);
1201 io_pid = -1;
1202 return 0;
1203 }
1204 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
1205 0, "ubd", ubd_devs);
1206 if(err != 0)
1207 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
1208 return 0;
1209}
1210
1211device_initcall(ubd_driver_init);
1212
1213static int ubd_open(struct block_device *bdev, fmode_t mode)
1214{
1215 struct gendisk *disk = bdev->bd_disk;
1216 struct ubd *ubd_dev = disk->private_data;
1217 int err = 0;
1218
1219 mutex_lock(&ubd_mutex);
1220 if(ubd_dev->count == 0){
1221 err = ubd_open_dev(ubd_dev);
1222 if(err){
1223 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
1224 disk->disk_name, ubd_dev->file, -err);
1225 goto out;
1226 }
1227 }
1228 ubd_dev->count++;
1229 set_disk_ro(disk, !ubd_dev->openflags.w);
1230
1231 /* This should no more be needed. And it didn't work anyway to exclude
1232 * read-write remounting of filesystems.*/
1233 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){
1234 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
1235 err = -EROFS;
1236 }*/
1237out:
1238 mutex_unlock(&ubd_mutex);
1239 return err;
1240}
1241
1242static void ubd_release(struct gendisk *disk, fmode_t mode)
1243{
1244 struct ubd *ubd_dev = disk->private_data;
1245
1246 mutex_lock(&ubd_mutex);
1247 if(--ubd_dev->count == 0)
1248 ubd_close_dev(ubd_dev);
1249 mutex_unlock(&ubd_mutex);
1250}
1251
1252static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
1253 __u64 *cow_offset, unsigned long *bitmap,
1254 __u64 bitmap_offset, unsigned long *bitmap_words,
1255 __u64 bitmap_len)
1256{
1257 __u64 sector = io_offset >> SECTOR_SHIFT;
1258 int i, update_bitmap = 0;
1259
1260 for (i = 0; i < length >> SECTOR_SHIFT; i++) {
1261 if(cow_mask != NULL)
1262 ubd_set_bit(i, (unsigned char *) cow_mask);
1263 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1264 continue;
1265
1266 update_bitmap = 1;
1267 ubd_set_bit(sector + i, (unsigned char *) bitmap);
1268 }
1269
1270 if(!update_bitmap)
1271 return;
1272
1273 *cow_offset = sector / (sizeof(unsigned long) * 8);
1274
1275 /* This takes care of the case where we're exactly at the end of the
1276 * device, and *cow_offset + 1 is off the end. So, just back it up
1277 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1278 * for the original diagnosis.
1279 */
1280 if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
1281 sizeof(unsigned long)) - 1))
1282 (*cow_offset)--;
1283
1284 bitmap_words[0] = bitmap[*cow_offset];
1285 bitmap_words[1] = bitmap[*cow_offset + 1];
1286
1287 *cow_offset *= sizeof(unsigned long);
1288 *cow_offset += bitmap_offset;
1289}
1290
1291static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
1292 __u64 bitmap_offset, __u64 bitmap_len)
1293{
1294 __u64 sector = req->offset >> SECTOR_SHIFT;
1295 int i;
1296
1297 if (req->length > (sizeof(req->sector_mask) * 8) << SECTOR_SHIFT)
1298 panic("Operation too long");
1299
1300 if (req_op(req->req) == REQ_OP_READ) {
1301 for (i = 0; i < req->length >> SECTOR_SHIFT; i++) {
1302 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1303 ubd_set_bit(i, (unsigned char *)
1304 &req->sector_mask);
1305 }
1306 }
1307 else cowify_bitmap(req->offset, req->length, &req->sector_mask,
1308 &req->cow_offset, bitmap, bitmap_offset,
1309 req->bitmap_words, bitmap_len);
1310}
1311
1312static int ubd_queue_one_vec(struct blk_mq_hw_ctx *hctx, struct request *req,
1313 u64 off, struct bio_vec *bvec)
1314{
1315 struct ubd *dev = hctx->queue->queuedata;
1316 struct io_thread_req *io_req;
1317 int ret;
1318
1319 io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC);
1320 if (!io_req)
1321 return -ENOMEM;
1322
1323 io_req->req = req;
1324 if (dev->cow.file)
1325 io_req->fds[0] = dev->cow.fd;
1326 else
1327 io_req->fds[0] = dev->fd;
1328 io_req->error = 0;
1329
1330 if (bvec != NULL) {
1331 io_req->buffer = page_address(bvec->bv_page) + bvec->bv_offset;
1332 io_req->length = bvec->bv_len;
1333 } else {
1334 io_req->buffer = NULL;
1335 io_req->length = blk_rq_bytes(req);
1336 }
1337
1338 io_req->sectorsize = SECTOR_SIZE;
1339 io_req->fds[1] = dev->fd;
1340 io_req->cow_offset = -1;
1341 io_req->offset = off;
1342 io_req->sector_mask = 0;
1343 io_req->offsets[0] = 0;
1344 io_req->offsets[1] = dev->cow.data_offset;
1345
1346 if (dev->cow.file)
1347 cowify_req(io_req, dev->cow.bitmap,
1348 dev->cow.bitmap_offset, dev->cow.bitmap_len);
1349
1350 ret = os_write_file(thread_fd, &io_req, sizeof(io_req));
1351 if (ret != sizeof(io_req)) {
1352 if (ret != -EAGAIN)
1353 pr_err("write to io thread failed: %d\n", -ret);
1354 kfree(io_req);
1355 }
1356 return ret;
1357}
1358
1359static int queue_rw_req(struct blk_mq_hw_ctx *hctx, struct request *req)
1360{
1361 struct req_iterator iter;
1362 struct bio_vec bvec;
1363 int ret;
1364 u64 off = (u64)blk_rq_pos(req) << SECTOR_SHIFT;
1365
1366 rq_for_each_segment(bvec, req, iter) {
1367 ret = ubd_queue_one_vec(hctx, req, off, &bvec);
1368 if (ret < 0)
1369 return ret;
1370 off += bvec.bv_len;
1371 }
1372 return 0;
1373}
1374
1375static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
1376 const struct blk_mq_queue_data *bd)
1377{
1378 struct ubd *ubd_dev = hctx->queue->queuedata;
1379 struct request *req = bd->rq;
1380 int ret = 0, res = BLK_STS_OK;
1381
1382 blk_mq_start_request(req);
1383
1384 spin_lock_irq(&ubd_dev->lock);
1385
1386 switch (req_op(req)) {
1387 /* operations with no lentgth/offset arguments */
1388 case REQ_OP_FLUSH:
1389 ret = ubd_queue_one_vec(hctx, req, 0, NULL);
1390 break;
1391 case REQ_OP_READ:
1392 case REQ_OP_WRITE:
1393 ret = queue_rw_req(hctx, req);
1394 break;
1395 case REQ_OP_DISCARD:
1396 case REQ_OP_WRITE_ZEROES:
1397 ret = ubd_queue_one_vec(hctx, req, (u64)blk_rq_pos(req) << 9, NULL);
1398 break;
1399 default:
1400 WARN_ON_ONCE(1);
1401 res = BLK_STS_NOTSUPP;
1402 }
1403
1404 spin_unlock_irq(&ubd_dev->lock);
1405
1406 if (ret < 0) {
1407 if (ret == -ENOMEM)
1408 res = BLK_STS_RESOURCE;
1409 else
1410 res = BLK_STS_DEV_RESOURCE;
1411 }
1412
1413 return res;
1414}
1415
1416static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1417{
1418 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1419
1420 geo->heads = 128;
1421 geo->sectors = 32;
1422 geo->cylinders = ubd_dev->size / (128 * 32 * 512);
1423 return 0;
1424}
1425
1426static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
1427 unsigned int cmd, unsigned long arg)
1428{
1429 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1430 u16 ubd_id[ATA_ID_WORDS];
1431
1432 switch (cmd) {
1433 struct cdrom_volctrl volume;
1434 case HDIO_GET_IDENTITY:
1435 memset(&ubd_id, 0, ATA_ID_WORDS * 2);
1436 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512);
1437 ubd_id[ATA_ID_HEADS] = 128;
1438 ubd_id[ATA_ID_SECTORS] = 32;
1439 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1440 sizeof(ubd_id)))
1441 return -EFAULT;
1442 return 0;
1443
1444 case CDROMVOLREAD:
1445 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1446 return -EFAULT;
1447 volume.channel0 = 255;
1448 volume.channel1 = 255;
1449 volume.channel2 = 255;
1450 volume.channel3 = 255;
1451 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1452 return -EFAULT;
1453 return 0;
1454 }
1455 return -EINVAL;
1456}
1457
1458static int map_error(int error_code)
1459{
1460 switch (error_code) {
1461 case 0:
1462 return BLK_STS_OK;
1463 case ENOSYS:
1464 case EOPNOTSUPP:
1465 return BLK_STS_NOTSUPP;
1466 case ENOSPC:
1467 return BLK_STS_NOSPC;
1468 }
1469 return BLK_STS_IOERR;
1470}
1471
1472/*
1473 * Everything from here onwards *IS NOT PART OF THE KERNEL*
1474 *
1475 * The following functions are part of UML hypervisor code.
1476 * All functions from here onwards are executed as a helper
1477 * thread and are not allowed to execute any kernel functions.
1478 *
1479 * Any communication must occur strictly via shared memory and IPC.
1480 *
1481 * Do not add printks, locks, kernel memory operations, etc - it
1482 * will result in unpredictable behaviour and/or crashes.
1483 */
1484
1485static int update_bitmap(struct io_thread_req *req)
1486{
1487 int n;
1488
1489 if(req->cow_offset == -1)
1490 return map_error(0);
1491
1492 n = os_pwrite_file(req->fds[1], &req->bitmap_words,
1493 sizeof(req->bitmap_words), req->cow_offset);
1494 if (n != sizeof(req->bitmap_words))
1495 return map_error(-n);
1496
1497 return map_error(0);
1498}
1499
1500static void do_io(struct io_thread_req *req)
1501{
1502 char *buf = NULL;
1503 unsigned long len;
1504 int n, nsectors, start, end, bit;
1505 __u64 off;
1506
1507 /* FLUSH is really a special case, we cannot "case" it with others */
1508
1509 if (req_op(req->req) == REQ_OP_FLUSH) {
1510 /* fds[0] is always either the rw image or our cow file */
1511 req->error = map_error(-os_sync_file(req->fds[0]));
1512 return;
1513 }
1514
1515 nsectors = req->length / req->sectorsize;
1516 start = 0;
1517 do {
1518 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask);
1519 end = start;
1520 while((end < nsectors) &&
1521 (ubd_test_bit(end, (unsigned char *)
1522 &req->sector_mask) == bit))
1523 end++;
1524
1525 off = req->offset + req->offsets[bit] +
1526 start * req->sectorsize;
1527 len = (end - start) * req->sectorsize;
1528 if (req->buffer != NULL)
1529 buf = &req->buffer[start * req->sectorsize];
1530
1531 switch (req_op(req->req)) {
1532 case REQ_OP_READ:
1533 n = 0;
1534 do {
1535 buf = &buf[n];
1536 len -= n;
1537 n = os_pread_file(req->fds[bit], buf, len, off);
1538 if (n < 0) {
1539 req->error = map_error(-n);
1540 return;
1541 }
1542 } while((n < len) && (n != 0));
1543 if (n < len) memset(&buf[n], 0, len - n);
1544 break;
1545 case REQ_OP_WRITE:
1546 n = os_pwrite_file(req->fds[bit], buf, len, off);
1547 if(n != len){
1548 req->error = map_error(-n);
1549 return;
1550 }
1551 break;
1552 case REQ_OP_DISCARD:
1553 case REQ_OP_WRITE_ZEROES:
1554 n = os_falloc_punch(req->fds[bit], off, len);
1555 if (n) {
1556 req->error = map_error(-n);
1557 return;
1558 }
1559 break;
1560 default:
1561 WARN_ON_ONCE(1);
1562 req->error = BLK_STS_NOTSUPP;
1563 return;
1564 }
1565
1566 start = end;
1567 } while(start < nsectors);
1568
1569 req->error = update_bitmap(req);
1570}
1571
1572/* Changed in start_io_thread, which is serialized by being called only
1573 * from ubd_init, which is an initcall.
1574 */
1575int kernel_fd = -1;
1576
1577/* Only changed by the io thread. XXX: currently unused. */
1578static int io_count = 0;
1579
1580int io_thread(void *arg)
1581{
1582 int n, count, written, res;
1583
1584 os_fix_helper_signals();
1585
1586 while(1){
1587 n = bulk_req_safe_read(
1588 kernel_fd,
1589 io_req_buffer,
1590 &io_remainder,
1591 &io_remainder_size,
1592 UBD_REQ_BUFFER_SIZE
1593 );
1594 if (n < 0) {
1595 if (n == -EAGAIN) {
1596 ubd_read_poll(-1);
1597 continue;
1598 }
1599 }
1600
1601 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
1602 io_count++;
1603 do_io((*io_req_buffer)[count]);
1604 }
1605
1606 written = 0;
1607
1608 do {
1609 res = os_write_file(kernel_fd, ((char *) io_req_buffer) + written, n);
1610 if (res >= 0) {
1611 written += res;
1612 }
1613 if (written < n) {
1614 ubd_write_poll(-1);
1615 }
1616 } while (written < n);
1617 }
1618
1619 return 0;
1620}