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