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Linux 5.8-rc4
[linux/fpc-iii.git] / arch / um / drivers / ubd_kern.c
blobeae8c83364f71826dcececea5a481f7b5831fd9e
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
50 struct 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
65 static struct io_thread_req * (*irq_req_buffer)[];
66 static struct io_thread_req *irq_remainder;
67 static int irq_remainder_size;
68
69 static struct io_thread_req * (*io_req_buffer)[];
70 static struct io_thread_req *io_remainder;
71 static int io_remainder_size;
72
73
74
75 static 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
86 static 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
100 static DEFINE_MUTEX(ubd_lock);
101 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
102
103 static int ubd_open(struct block_device *bdev, fmode_t mode);
104 static void ubd_release(struct gendisk *disk, fmode_t mode);
105 static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
106 unsigned int cmd, unsigned long arg);
107 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
108
109 #define MAX_DEV (16)
110
111 static const struct block_device_operations ubd_blops = {
112 .owner = THIS_MODULE,
113 .open = ubd_open,
114 .release = ubd_release,
115 .ioctl = ubd_ioctl,
116 .compat_ioctl = blkdev_compat_ptr_ioctl,
117 .getgeo = ubd_getgeo,
118 };
119
120 /* Protected by ubd_lock */
121 static int fake_major = UBD_MAJOR;
122 static struct gendisk *ubd_gendisk[MAX_DEV];
123 static struct gendisk *fake_gendisk[MAX_DEV];
124
125 #ifdef CONFIG_BLK_DEV_UBD_SYNC
126 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
127 .cl = 1 })
128 #else
129 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
130 .cl = 1 })
131 #endif
132 static struct openflags global_openflags = OPEN_FLAGS;
133
134 struct cow {
135 /* backing file name */
136 char *file;
137 /* backing file fd */
138 int fd;
139 unsigned long *bitmap;
140 unsigned long bitmap_len;
141 int bitmap_offset;
142 int data_offset;
143 };
144
145 #define MAX_SG 64
146
147 struct ubd {
148 /* name (and fd, below) of the file opened for writing, either the
149 * backing or the cow file. */
150 char *file;
151 int count;
152 int fd;
153 __u64 size;
154 struct openflags boot_openflags;
155 struct openflags openflags;
156 unsigned shared:1;
157 unsigned no_cow:1;
158 unsigned no_trim:1;
159 struct cow cow;
160 struct platform_device pdev;
161 struct request_queue *queue;
162 struct blk_mq_tag_set tag_set;
163 spinlock_t lock;
164 };
165
166 #define DEFAULT_COW { \
167 .file = NULL, \
168 .fd = -1, \
169 .bitmap = NULL, \
170 .bitmap_offset = 0, \
171 .data_offset = 0, \
172 }
173
174 #define DEFAULT_UBD { \
175 .file = NULL, \
176 .count = 0, \
177 .fd = -1, \
178 .size = -1, \
179 .boot_openflags = OPEN_FLAGS, \
180 .openflags = OPEN_FLAGS, \
181 .no_cow = 0, \
182 .no_trim = 0, \
183 .shared = 0, \
184 .cow = DEFAULT_COW, \
185 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
186 }
187
188 /* Protected by ubd_lock */
189 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
190
191 /* Only changed by fake_ide_setup which is a setup */
192 static int fake_ide = 0;
193 static struct proc_dir_entry *proc_ide_root = NULL;
194 static struct proc_dir_entry *proc_ide = NULL;
195
196 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
197 const struct blk_mq_queue_data *bd);
198
199 static void make_proc_ide(void)
200 {
201 proc_ide_root = proc_mkdir("ide", NULL);
202 proc_ide = proc_mkdir("ide0", proc_ide_root);
203 }
204
205 static int fake_ide_media_proc_show(struct seq_file *m, void *v)
206 {
207 seq_puts(m, "disk\n");
208 return 0;
209 }
210
211 static void make_ide_entries(const char *dev_name)
212 {
213 struct proc_dir_entry *dir, *ent;
214 char name[64];
215
216 if(proc_ide_root == NULL) make_proc_ide();
217
218 dir = proc_mkdir(dev_name, proc_ide);
219 if(!dir) return;
220
221 ent = proc_create_single("media", S_IRUGO, dir,
222 fake_ide_media_proc_show);
223 if(!ent) return;
224 snprintf(name, sizeof(name), "ide0/%s", dev_name);
225 proc_symlink(dev_name, proc_ide_root, name);
226 }
227
228 static int fake_ide_setup(char *str)
229 {
230 fake_ide = 1;
231 return 1;
232 }
233
234 __setup("fake_ide", fake_ide_setup);
235
236 __uml_help(fake_ide_setup,
237 "fake_ide\n"
238 " Create ide0 entries that map onto ubd devices.\n\n"
239 );
240
241 static int parse_unit(char **ptr)
242 {
243 char *str = *ptr, *end;
244 int n = -1;
245
246 if(isdigit(*str)) {
247 n = simple_strtoul(str, &end, 0);
248 if(end == str)
249 return -1;
250 *ptr = end;
251 }
252 else if (('a' <= *str) && (*str <= 'z')) {
253 n = *str - 'a';
254 str++;
255 *ptr = str;
256 }
257 return n;
258 }
259
260 /* If *index_out == -1 at exit, the passed option was a general one;
261 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
262 * should not be freed on exit.
263 */
264 static int ubd_setup_common(char *str, int *index_out, char **error_out)
265 {
266 struct ubd *ubd_dev;
267 struct openflags flags = global_openflags;
268 char *backing_file;
269 int n, err = 0, i;
270
271 if(index_out) *index_out = -1;
272 n = *str;
273 if(n == '='){
274 char *end;
275 int major;
276
277 str++;
278 if(!strcmp(str, "sync")){
279 global_openflags = of_sync(global_openflags);
280 return err;
281 }
282
283 err = -EINVAL;
284 major = simple_strtoul(str, &end, 0);
285 if((*end != '\0') || (end == str)){
286 *error_out = "Didn't parse major number";
287 return err;
288 }
289
290 mutex_lock(&ubd_lock);
291 if (fake_major != UBD_MAJOR) {
292 *error_out = "Can't assign a fake major twice";
293 goto out1;
294 }
295
296 fake_major = major;
297
298 printk(KERN_INFO "Setting extra ubd major number to %d\n",
299 major);
300 err = 0;
301 out1:
302 mutex_unlock(&ubd_lock);
303 return err;
304 }
305
306 n = parse_unit(&str);
307 if(n < 0){
308 *error_out = "Couldn't parse device number";
309 return -EINVAL;
310 }
311 if(n >= MAX_DEV){
312 *error_out = "Device number out of range";
313 return 1;
314 }
315
316 err = -EBUSY;
317 mutex_lock(&ubd_lock);
318
319 ubd_dev = &ubd_devs[n];
320 if(ubd_dev->file != NULL){
321 *error_out = "Device is already configured";
322 goto out;
323 }
324
325 if (index_out)
326 *index_out = n;
327
328 err = -EINVAL;
329 for (i = 0; i < sizeof("rscdt="); i++) {
330 switch (*str) {
331 case 'r':
332 flags.w = 0;
333 break;
334 case 's':
335 flags.s = 1;
336 break;
337 case 'd':
338 ubd_dev->no_cow = 1;
339 break;
340 case 'c':
341 ubd_dev->shared = 1;
342 break;
343 case 't':
344 ubd_dev->no_trim = 1;
345 break;
346 case '=':
347 str++;
348 goto break_loop;
349 default:
350 *error_out = "Expected '=' or flag letter "
351 "(r, s, c, t or d)";
352 goto out;
353 }
354 str++;
355 }
356
357 if (*str == '=')
358 *error_out = "Too many flags specified";
359 else
360 *error_out = "Missing '='";
361 goto out;
362
363 break_loop:
364 backing_file = strchr(str, ',');
365
366 if (backing_file == NULL)
367 backing_file = strchr(str, ':');
368
369 if(backing_file != NULL){
370 if(ubd_dev->no_cow){
371 *error_out = "Can't specify both 'd' and a cow file";
372 goto out;
373 }
374 else {
375 *backing_file = '\0';
376 backing_file++;
377 }
378 }
379 err = 0;
380 ubd_dev->file = str;
381 ubd_dev->cow.file = backing_file;
382 ubd_dev->boot_openflags = flags;
383 out:
384 mutex_unlock(&ubd_lock);
385 return err;
386 }
387
388 static int ubd_setup(char *str)
389 {
390 char *error;
391 int err;
392
393 err = ubd_setup_common(str, NULL, &error);
394 if(err)
395 printk(KERN_ERR "Failed to initialize device with \"%s\" : "
396 "%s\n", str, error);
397 return 1;
398 }
399
400 __setup("ubd", ubd_setup);
401 __uml_help(ubd_setup,
402 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
403 " This is used to associate a device with a file in the underlying\n"
404 " filesystem. When specifying two filenames, the first one is the\n"
405 " COW name and the second is the backing file name. As separator you can\n"
406 " use either a ':' or a ',': the first one allows writing things like;\n"
407 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
408 " while with a ',' the shell would not expand the 2nd '~'.\n"
409 " When using only one filename, UML will detect whether to treat it like\n"
410 " a COW file or a backing file. To override this detection, add the 'd'\n"
411 " flag:\n"
412 " ubd0d=BackingFile\n"
413 " Usually, there is a filesystem in the file, but \n"
414 " that's not required. Swap devices containing swap files can be\n"
415 " specified like this. Also, a file which doesn't contain a\n"
416 " filesystem can have its contents read in the virtual \n"
417 " machine by running 'dd' on the device. <n> must be in the range\n"
418 " 0 to 7. Appending an 'r' to the number will cause that device\n"
419 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
420 " an 's' will cause data to be written to disk on the host immediately.\n"
421 " 'c' will cause the device to be treated as being shared between multiple\n"
422 " UMLs and file locking will be turned off - this is appropriate for a\n"
423 " cluster filesystem and inappropriate at almost all other times.\n\n"
424 " 't' will disable trim/discard support on the device (enabled by default).\n\n"
425 );
426
427 static int udb_setup(char *str)
428 {
429 printk("udb%s specified on command line is almost certainly a ubd -> "
430 "udb TYPO\n", str);
431 return 1;
432 }
433
434 __setup("udb", udb_setup);
435 __uml_help(udb_setup,
436 "udb\n"
437 " This option is here solely to catch ubd -> udb typos, which can be\n"
438 " to impossible to catch visually unless you specifically look for\n"
439 " them. The only result of any option starting with 'udb' is an error\n"
440 " in the boot output.\n\n"
441 );
442
443 /* Only changed by ubd_init, which is an initcall. */
444 static int thread_fd = -1;
445
446 /* Function to read several request pointers at a time
447 * handling fractional reads if (and as) needed
448 */
449
450 static int bulk_req_safe_read(
451 int fd,
452 struct io_thread_req * (*request_buffer)[],
453 struct io_thread_req **remainder,
454 int *remainder_size,
455 int max_recs
456 )
457 {
458 int n = 0;
459 int res = 0;
460
461 if (*remainder_size > 0) {
462 memmove(
463 (char *) request_buffer,
464 (char *) remainder, *remainder_size
465 );
466 n = *remainder_size;
467 }
468
469 res = os_read_file(
470 fd,
471 ((char *) request_buffer) + *remainder_size,
472 sizeof(struct io_thread_req *)*max_recs
473 - *remainder_size
474 );
475 if (res > 0) {
476 n += res;
477 if ((n % sizeof(struct io_thread_req *)) > 0) {
478 /*
479 * Read somehow returned not a multiple of dword
480 * theoretically possible, but never observed in the
481 * wild, so read routine must be able to handle it
482 */
483 *remainder_size = n % sizeof(struct io_thread_req *);
484 WARN(*remainder_size > 0, "UBD IPC read returned a partial result");
485 memmove(
486 remainder,
487 ((char *) request_buffer) +
488 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *),
489 *remainder_size
490 );
491 n = n - *remainder_size;
492 }
493 } else {
494 n = res;
495 }
496 return n;
497 }
498
499 /* Called without dev->lock held, and only in interrupt context. */
500 static void ubd_handler(void)
501 {
502 int n;
503 int count;
504
505 while(1){
506 n = bulk_req_safe_read(
507 thread_fd,
508 irq_req_buffer,
509 &irq_remainder,
510 &irq_remainder_size,
511 UBD_REQ_BUFFER_SIZE
512 );
513 if (n < 0) {
514 if(n == -EAGAIN)
515 break;
516 printk(KERN_ERR "spurious interrupt in ubd_handler, "
517 "err = %d\n", -n);
518 return;
519 }
520 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
521 struct io_thread_req *io_req = (*irq_req_buffer)[count];
522
523 if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
524 blk_queue_max_discard_sectors(io_req->req->q, 0);
525 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
526 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q);
527 }
528 if ((io_req->error) || (io_req->buffer == NULL))
529 blk_mq_end_request(io_req->req, io_req->error);
530 else {
531 if (!blk_update_request(io_req->req, io_req->error, io_req->length))
532 __blk_mq_end_request(io_req->req, io_req->error);
533 }
534 kfree(io_req);
535 }
536 }
537 }
538
539 static irqreturn_t ubd_intr(int irq, void *dev)
540 {
541 ubd_handler();
542 return IRQ_HANDLED;
543 }
544
545 /* Only changed by ubd_init, which is an initcall. */
546 static int io_pid = -1;
547
548 static void kill_io_thread(void)
549 {
550 if(io_pid != -1)
551 os_kill_process(io_pid, 1);
552 }
553
554 __uml_exitcall(kill_io_thread);
555
556 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
557 {
558 char *file;
559 int fd;
560 int err;
561
562 __u32 version;
563 __u32 align;
564 char *backing_file;
565 time64_t mtime;
566 unsigned long long size;
567 int sector_size;
568 int bitmap_offset;
569
570 if (ubd_dev->file && ubd_dev->cow.file) {
571 file = ubd_dev->cow.file;
572
573 goto out;
574 }
575
576 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0);
577 if (fd < 0)
578 return fd;
579
580 err = read_cow_header(file_reader, &fd, &version, &backing_file, \
581 &mtime, &size, &sector_size, &align, &bitmap_offset);
582 os_close_file(fd);
583
584 if(err == -EINVAL)
585 file = ubd_dev->file;
586 else
587 file = backing_file;
588
589 out:
590 return os_file_size(file, size_out);
591 }
592
593 static int read_cow_bitmap(int fd, void *buf, int offset, int len)
594 {
595 int err;
596
597 err = os_pread_file(fd, buf, len, offset);
598 if (err < 0)
599 return err;
600
601 return 0;
602 }
603
604 static int backing_file_mismatch(char *file, __u64 size, time64_t mtime)
605 {
606 time64_t modtime;
607 unsigned long long actual;
608 int err;
609
610 err = os_file_modtime(file, &modtime);
611 if (err < 0) {
612 printk(KERN_ERR "Failed to get modification time of backing "
613 "file \"%s\", err = %d\n", file, -err);
614 return err;
615 }
616
617 err = os_file_size(file, &actual);
618 if (err < 0) {
619 printk(KERN_ERR "Failed to get size of backing file \"%s\", "
620 "err = %d\n", file, -err);
621 return err;
622 }
623
624 if (actual != size) {
625 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
626 * the typecast.*/
627 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header "
628 "vs backing file\n", (unsigned long long) size, actual);
629 return -EINVAL;
630 }
631 if (modtime != mtime) {
632 printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs "
633 "backing file\n", mtime, modtime);
634 return -EINVAL;
635 }
636 return 0;
637 }
638
639 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
640 {
641 struct uml_stat buf1, buf2;
642 int err;
643
644 if (from_cmdline == NULL)
645 return 0;
646 if (!strcmp(from_cmdline, from_cow))
647 return 0;
648
649 err = os_stat_file(from_cmdline, &buf1);
650 if (err < 0) {
651 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline,
652 -err);
653 return 0;
654 }
655 err = os_stat_file(from_cow, &buf2);
656 if (err < 0) {
657 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow,
658 -err);
659 return 1;
660 }
661 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
662 return 0;
663
664 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, "
665 "\"%s\" specified in COW header of \"%s\"\n",
666 from_cmdline, from_cow, cow);
667 return 1;
668 }
669
670 static int open_ubd_file(char *file, struct openflags *openflags, int shared,
671 char **backing_file_out, int *bitmap_offset_out,
672 unsigned long *bitmap_len_out, int *data_offset_out,
673 int *create_cow_out)
674 {
675 time64_t mtime;
676 unsigned long long size;
677 __u32 version, align;
678 char *backing_file;
679 int fd, err, sectorsize, asked_switch, mode = 0644;
680
681 fd = os_open_file(file, *openflags, mode);
682 if (fd < 0) {
683 if ((fd == -ENOENT) && (create_cow_out != NULL))
684 *create_cow_out = 1;
685 if (!openflags->w ||
686 ((fd != -EROFS) && (fd != -EACCES)))
687 return fd;
688 openflags->w = 0;
689 fd = os_open_file(file, *openflags, mode);
690 if (fd < 0)
691 return fd;
692 }
693
694 if (shared)
695 printk(KERN_INFO "Not locking \"%s\" on the host\n", file);
696 else {
697 err = os_lock_file(fd, openflags->w);
698 if (err < 0) {
699 printk(KERN_ERR "Failed to lock '%s', err = %d\n",
700 file, -err);
701 goto out_close;
702 }
703 }
704
705 /* Successful return case! */
706 if (backing_file_out == NULL)
707 return fd;
708
709 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
710 &size, &sectorsize, &align, bitmap_offset_out);
711 if (err && (*backing_file_out != NULL)) {
712 printk(KERN_ERR "Failed to read COW header from COW file "
713 "\"%s\", errno = %d\n", file, -err);
714 goto out_close;
715 }
716 if (err)
717 return fd;
718
719 asked_switch = path_requires_switch(*backing_file_out, backing_file,
720 file);
721
722 /* Allow switching only if no mismatch. */
723 if (asked_switch && !backing_file_mismatch(*backing_file_out, size,
724 mtime)) {
725 printk(KERN_ERR "Switching backing file to '%s'\n",
726 *backing_file_out);
727 err = write_cow_header(file, fd, *backing_file_out,
728 sectorsize, align, &size);
729 if (err) {
730 printk(KERN_ERR "Switch failed, errno = %d\n", -err);
731 goto out_close;
732 }
733 } else {
734 *backing_file_out = backing_file;
735 err = backing_file_mismatch(*backing_file_out, size, mtime);
736 if (err)
737 goto out_close;
738 }
739
740 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
741 bitmap_len_out, data_offset_out);
742
743 return fd;
744 out_close:
745 os_close_file(fd);
746 return err;
747 }
748
749 static int create_cow_file(char *cow_file, char *backing_file,
750 struct openflags flags,
751 int sectorsize, int alignment, int *bitmap_offset_out,
752 unsigned long *bitmap_len_out, int *data_offset_out)
753 {
754 int err, fd;
755
756 flags.c = 1;
757 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL);
758 if (fd < 0) {
759 err = fd;
760 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n",
761 cow_file, -err);
762 goto out;
763 }
764
765 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
766 bitmap_offset_out, bitmap_len_out,
767 data_offset_out);
768 if (!err)
769 return fd;
770 os_close_file(fd);
771 out:
772 return err;
773 }
774
775 static void ubd_close_dev(struct ubd *ubd_dev)
776 {
777 os_close_file(ubd_dev->fd);
778 if(ubd_dev->cow.file == NULL)
779 return;
780
781 os_close_file(ubd_dev->cow.fd);
782 vfree(ubd_dev->cow.bitmap);
783 ubd_dev->cow.bitmap = NULL;
784 }
785
786 static int ubd_open_dev(struct ubd *ubd_dev)
787 {
788 struct openflags flags;
789 char **back_ptr;
790 int err, create_cow, *create_ptr;
791 int fd;
792
793 ubd_dev->openflags = ubd_dev->boot_openflags;
794 create_cow = 0;
795 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
796 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;
797
798 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
799 back_ptr, &ubd_dev->cow.bitmap_offset,
800 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
801 create_ptr);
802
803 if((fd == -ENOENT) && create_cow){
804 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
805 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE,
806 &ubd_dev->cow.bitmap_offset,
807 &ubd_dev->cow.bitmap_len,
808 &ubd_dev->cow.data_offset);
809 if(fd >= 0){
810 printk(KERN_INFO "Creating \"%s\" as COW file for "
811 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
812 }
813 }
814
815 if(fd < 0){
816 printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
817 -fd);
818 return fd;
819 }
820 ubd_dev->fd = fd;
821
822 if(ubd_dev->cow.file != NULL){
823 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long));
824
825 err = -ENOMEM;
826 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
827 if(ubd_dev->cow.bitmap == NULL){
828 printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
829 goto error;
830 }
831 flush_tlb_kernel_vm();
832
833 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
834 ubd_dev->cow.bitmap_offset,
835 ubd_dev->cow.bitmap_len);
836 if(err < 0)
837 goto error;
838
839 flags = ubd_dev->openflags;
840 flags.w = 0;
841 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
842 NULL, NULL, NULL, NULL);
843 if(err < 0) goto error;
844 ubd_dev->cow.fd = err;
845 }
846 if (ubd_dev->no_trim == 0) {
847 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
848 ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE;
849 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
850 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
851 blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue);
852 }
853 blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
854 return 0;
855 error:
856 os_close_file(ubd_dev->fd);
857 return err;
858 }
859
860 static void ubd_device_release(struct device *dev)
861 {
862 struct ubd *ubd_dev = dev_get_drvdata(dev);
863
864 blk_cleanup_queue(ubd_dev->queue);
865 blk_mq_free_tag_set(&ubd_dev->tag_set);
866 *ubd_dev = ((struct ubd) DEFAULT_UBD);
867 }
868
869 static int ubd_disk_register(int major, u64 size, int unit,
870 struct gendisk **disk_out)
871 {
872 struct device *parent = NULL;
873 struct gendisk *disk;
874
875 disk = alloc_disk(1 << UBD_SHIFT);
876 if(disk == NULL)
877 return -ENOMEM;
878
879 disk->major = major;
880 disk->first_minor = unit << UBD_SHIFT;
881 disk->fops = &ubd_blops;
882 set_capacity(disk, size / 512);
883 if (major == UBD_MAJOR)
884 sprintf(disk->disk_name, "ubd%c", 'a' + unit);
885 else
886 sprintf(disk->disk_name, "ubd_fake%d", unit);
887
888 /* sysfs register (not for ide fake devices) */
889 if (major == UBD_MAJOR) {
890 ubd_devs[unit].pdev.id = unit;
891 ubd_devs[unit].pdev.name = DRIVER_NAME;
892 ubd_devs[unit].pdev.dev.release = ubd_device_release;
893 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
894 platform_device_register(&ubd_devs[unit].pdev);
895 parent = &ubd_devs[unit].pdev.dev;
896 }
897
898 disk->private_data = &ubd_devs[unit];
899 disk->queue = ubd_devs[unit].queue;
900 device_add_disk(parent, disk, NULL);
901
902 *disk_out = disk;
903 return 0;
904 }
905
906 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
907
908 static const struct blk_mq_ops ubd_mq_ops = {
909 .queue_rq = ubd_queue_rq,
910 };
911
912 static int ubd_add(int n, char **error_out)
913 {
914 struct ubd *ubd_dev = &ubd_devs[n];
915 int err = 0;
916
917 if(ubd_dev->file == NULL)
918 goto out;
919
920 err = ubd_file_size(ubd_dev, &ubd_dev->size);
921 if(err < 0){
922 *error_out = "Couldn't determine size of device's file";
923 goto out;
924 }
925
926 ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
927
928 ubd_dev->tag_set.ops = &ubd_mq_ops;
929 ubd_dev->tag_set.queue_depth = 64;
930 ubd_dev->tag_set.numa_node = NUMA_NO_NODE;
931 ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
932 ubd_dev->tag_set.driver_data = ubd_dev;
933 ubd_dev->tag_set.nr_hw_queues = 1;
934
935 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set);
936 if (err)
937 goto out;
938
939 ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set);
940 if (IS_ERR(ubd_dev->queue)) {
941 err = PTR_ERR(ubd_dev->queue);
942 goto out_cleanup_tags;
943 }
944
945 ubd_dev->queue->queuedata = ubd_dev;
946 blk_queue_write_cache(ubd_dev->queue, true, false);
947
948 blk_queue_max_segments(ubd_dev->queue, MAX_SG);
949 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
950 if(err){
951 *error_out = "Failed to register device";
952 goto out_cleanup_tags;
953 }
954
955 if (fake_major != UBD_MAJOR)
956 ubd_disk_register(fake_major, ubd_dev->size, n,
957 &fake_gendisk[n]);
958
959 /*
960 * Perhaps this should also be under the "if (fake_major)" above
961 * using the fake_disk->disk_name
962 */
963 if (fake_ide)
964 make_ide_entries(ubd_gendisk[n]->disk_name);
965
966 err = 0;
967 out:
968 return err;
969
970 out_cleanup_tags:
971 blk_mq_free_tag_set(&ubd_dev->tag_set);
972 if (!(IS_ERR(ubd_dev->queue)))
973 blk_cleanup_queue(ubd_dev->queue);
974 goto out;
975 }
976
977 static int ubd_config(char *str, char **error_out)
978 {
979 int n, ret;
980
981 /* This string is possibly broken up and stored, so it's only
982 * freed if ubd_setup_common fails, or if only general options
983 * were set.
984 */
985 str = kstrdup(str, GFP_KERNEL);
986 if (str == NULL) {
987 *error_out = "Failed to allocate memory";
988 return -ENOMEM;
989 }
990
991 ret = ubd_setup_common(str, &n, error_out);
992 if (ret)
993 goto err_free;
994
995 if (n == -1) {
996 ret = 0;
997 goto err_free;
998 }
999
1000 mutex_lock(&ubd_lock);
1001 ret = ubd_add(n, error_out);
1002 if (ret)
1003 ubd_devs[n].file = NULL;
1004 mutex_unlock(&ubd_lock);
1005
1006 out:
1007 return ret;
1008
1009 err_free:
1010 kfree(str);
1011 goto out;
1012 }
1013
1014 static int ubd_get_config(char *name, char *str, int size, char **error_out)
1015 {
1016 struct ubd *ubd_dev;
1017 int n, len = 0;
1018
1019 n = parse_unit(&name);
1020 if((n >= MAX_DEV) || (n < 0)){
1021 *error_out = "ubd_get_config : device number out of range";
1022 return -1;
1023 }
1024
1025 ubd_dev = &ubd_devs[n];
1026 mutex_lock(&ubd_lock);
1027
1028 if(ubd_dev->file == NULL){
1029 CONFIG_CHUNK(str, size, len, "", 1);
1030 goto out;
1031 }
1032
1033 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0);
1034
1035 if(ubd_dev->cow.file != NULL){
1036 CONFIG_CHUNK(str, size, len, ",", 0);
1037 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1);
1038 }
1039 else CONFIG_CHUNK(str, size, len, "", 1);
1040
1041 out:
1042 mutex_unlock(&ubd_lock);
1043 return len;
1044 }
1045
1046 static int ubd_id(char **str, int *start_out, int *end_out)
1047 {
1048 int n;
1049
1050 n = parse_unit(str);
1051 *start_out = 0;
1052 *end_out = MAX_DEV - 1;
1053 return n;
1054 }
1055
1056 static int ubd_remove(int n, char **error_out)
1057 {
1058 struct gendisk *disk = ubd_gendisk[n];
1059 struct ubd *ubd_dev;
1060 int err = -ENODEV;
1061
1062 mutex_lock(&ubd_lock);
1063
1064 ubd_dev = &ubd_devs[n];
1065
1066 if(ubd_dev->file == NULL)
1067 goto out;
1068
1069 /* you cannot remove a open disk */
1070 err = -EBUSY;
1071 if(ubd_dev->count > 0)
1072 goto out;
1073
1074 ubd_gendisk[n] = NULL;
1075 if(disk != NULL){
1076 del_gendisk(disk);
1077 put_disk(disk);
1078 }
1079
1080 if(fake_gendisk[n] != NULL){
1081 del_gendisk(fake_gendisk[n]);
1082 put_disk(fake_gendisk[n]);
1083 fake_gendisk[n] = NULL;
1084 }
1085
1086 err = 0;
1087 platform_device_unregister(&ubd_dev->pdev);
1088 out:
1089 mutex_unlock(&ubd_lock);
1090 return err;
1091 }
1092
1093 /* All these are called by mconsole in process context and without
1094 * ubd-specific locks. The structure itself is const except for .list.
1095 */
1096 static struct mc_device ubd_mc = {
1097 .list = LIST_HEAD_INIT(ubd_mc.list),
1098 .name = "ubd",
1099 .config = ubd_config,
1100 .get_config = ubd_get_config,
1101 .id = ubd_id,
1102 .remove = ubd_remove,
1103 };
1104
1105 static int __init ubd_mc_init(void)
1106 {
1107 mconsole_register_dev(&ubd_mc);
1108 return 0;
1109 }
1110
1111 __initcall(ubd_mc_init);
1112
1113 static int __init ubd0_init(void)
1114 {
1115 struct ubd *ubd_dev = &ubd_devs[0];
1116
1117 mutex_lock(&ubd_lock);
1118 if(ubd_dev->file == NULL)
1119 ubd_dev->file = "root_fs";
1120 mutex_unlock(&ubd_lock);
1121
1122 return 0;
1123 }
1124
1125 __initcall(ubd0_init);
1126
1127 /* Used in ubd_init, which is an initcall */
1128 static struct platform_driver ubd_driver = {
1129 .driver = {
1130 .name = DRIVER_NAME,
1131 },
1132 };
1133
1134 static int __init ubd_init(void)
1135 {
1136 char *error;
1137 int i, err;
1138
1139 if (register_blkdev(UBD_MAJOR, "ubd"))
1140 return -1;
1141
1142 if (fake_major != UBD_MAJOR) {
1143 char name[sizeof("ubd_nnn\0")];
1144
1145 snprintf(name, sizeof(name), "ubd_%d", fake_major);
1146 if (register_blkdev(fake_major, "ubd"))
1147 return -1;
1148 }
1149
1150 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1151 sizeof(struct io_thread_req *),
1152 GFP_KERNEL
1153 );
1154 irq_remainder = 0;
1155
1156 if (irq_req_buffer == NULL) {
1157 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1158 return -1;
1159 }
1160 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1161 sizeof(struct io_thread_req *),
1162 GFP_KERNEL
1163 );
1164
1165 io_remainder = 0;
1166
1167 if (io_req_buffer == NULL) {
1168 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1169 return -1;
1170 }
1171 platform_driver_register(&ubd_driver);
1172 mutex_lock(&ubd_lock);
1173 for (i = 0; i < MAX_DEV; i++){
1174 err = ubd_add(i, &error);
1175 if(err)
1176 printk(KERN_ERR "Failed to initialize ubd device %d :"
1177 "%s\n", i, error);
1178 }
1179 mutex_unlock(&ubd_lock);
1180 return 0;
1181 }
1182
1183 late_initcall(ubd_init);
1184
1185 static int __init ubd_driver_init(void){
1186 unsigned long stack;
1187 int err;
1188
1189 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
1190 if(global_openflags.s){
1191 printk(KERN_INFO "ubd: Synchronous mode\n");
1192 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
1193 * enough. So use anyway the io thread. */
1194 }
1195 stack = alloc_stack(0, 0);
1196 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
1197 &thread_fd);
1198 if(io_pid < 0){
1199 printk(KERN_ERR
1200 "ubd : Failed to start I/O thread (errno = %d) - "
1201 "falling back to synchronous I/O\n", -io_pid);
1202 io_pid = -1;
1203 return 0;
1204 }
1205 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
1206 0, "ubd", ubd_devs);
1207 if(err != 0)
1208 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
1209 return 0;
1210 }
1211
1212 device_initcall(ubd_driver_init);
1213
1214 static int ubd_open(struct block_device *bdev, fmode_t mode)
1215 {
1216 struct gendisk *disk = bdev->bd_disk;
1217 struct ubd *ubd_dev = disk->private_data;
1218 int err = 0;
1219
1220 mutex_lock(&ubd_mutex);
1221 if(ubd_dev->count == 0){
1222 err = ubd_open_dev(ubd_dev);
1223 if(err){
1224 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
1225 disk->disk_name, ubd_dev->file, -err);
1226 goto out;
1227 }
1228 }
1229 ubd_dev->count++;
1230 set_disk_ro(disk, !ubd_dev->openflags.w);
1231
1232 /* This should no more be needed. And it didn't work anyway to exclude
1233 * read-write remounting of filesystems.*/
1234 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){
1235 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
1236 err = -EROFS;
1237 }*/
1238 out:
1239 mutex_unlock(&ubd_mutex);
1240 return err;
1241 }
1242
1243 static void ubd_release(struct gendisk *disk, fmode_t mode)
1244 {
1245 struct ubd *ubd_dev = disk->private_data;
1246
1247 mutex_lock(&ubd_mutex);
1248 if(--ubd_dev->count == 0)
1249 ubd_close_dev(ubd_dev);
1250 mutex_unlock(&ubd_mutex);
1251 }
1252
1253 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
1254 __u64 *cow_offset, unsigned long *bitmap,
1255 __u64 bitmap_offset, unsigned long *bitmap_words,
1256 __u64 bitmap_len)
1257 {
1258 __u64 sector = io_offset >> SECTOR_SHIFT;
1259 int i, update_bitmap = 0;
1260
1261 for (i = 0; i < length >> SECTOR_SHIFT; i++) {
1262 if(cow_mask != NULL)
1263 ubd_set_bit(i, (unsigned char *) cow_mask);
1264 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1265 continue;
1266
1267 update_bitmap = 1;
1268 ubd_set_bit(sector + i, (unsigned char *) bitmap);
1269 }
1270
1271 if(!update_bitmap)
1272 return;
1273
1274 *cow_offset = sector / (sizeof(unsigned long) * 8);
1275
1276 /* This takes care of the case where we're exactly at the end of the
1277 * device, and *cow_offset + 1 is off the end. So, just back it up
1278 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1279 * for the original diagnosis.
1280 */
1281 if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
1282 sizeof(unsigned long)) - 1))
1283 (*cow_offset)--;
1284
1285 bitmap_words[0] = bitmap[*cow_offset];
1286 bitmap_words[1] = bitmap[*cow_offset + 1];
1287
1288 *cow_offset *= sizeof(unsigned long);
1289 *cow_offset += bitmap_offset;
1290 }
1291
1292 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
1293 __u64 bitmap_offset, __u64 bitmap_len)
1294 {
1295 __u64 sector = req->offset >> SECTOR_SHIFT;
1296 int i;
1297
1298 if (req->length > (sizeof(req->sector_mask) * 8) << SECTOR_SHIFT)
1299 panic("Operation too long");
1300
1301 if (req_op(req->req) == REQ_OP_READ) {
1302 for (i = 0; i < req->length >> SECTOR_SHIFT; i++) {
1303 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1304 ubd_set_bit(i, (unsigned char *)
1305 &req->sector_mask);
1306 }
1307 }
1308 else cowify_bitmap(req->offset, req->length, &req->sector_mask,
1309 &req->cow_offset, bitmap, bitmap_offset,
1310 req->bitmap_words, bitmap_len);
1311 }
1312
1313 static int ubd_queue_one_vec(struct blk_mq_hw_ctx *hctx, struct request *req,
1314 u64 off, struct bio_vec *bvec)
1315 {
1316 struct ubd *dev = hctx->queue->queuedata;
1317 struct io_thread_req *io_req;
1318 int ret;
1319
1320 io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC);
1321 if (!io_req)
1322 return -ENOMEM;
1323
1324 io_req->req = req;
1325 if (dev->cow.file)
1326 io_req->fds[0] = dev->cow.fd;
1327 else
1328 io_req->fds[0] = dev->fd;
1329 io_req->error = 0;
1330
1331 if (bvec != NULL) {
1332 io_req->buffer = page_address(bvec->bv_page) + bvec->bv_offset;
1333 io_req->length = bvec->bv_len;
1334 } else {
1335 io_req->buffer = NULL;
1336 io_req->length = blk_rq_bytes(req);
1337 }
1338
1339 io_req->sectorsize = SECTOR_SIZE;
1340 io_req->fds[1] = dev->fd;
1341 io_req->cow_offset = -1;
1342 io_req->offset = off;
1343 io_req->sector_mask = 0;
1344 io_req->offsets[0] = 0;
1345 io_req->offsets[1] = dev->cow.data_offset;
1346
1347 if (dev->cow.file)
1348 cowify_req(io_req, dev->cow.bitmap,
1349 dev->cow.bitmap_offset, dev->cow.bitmap_len);
1350
1351 ret = os_write_file(thread_fd, &io_req, sizeof(io_req));
1352 if (ret != sizeof(io_req)) {
1353 if (ret != -EAGAIN)
1354 pr_err("write to io thread failed: %d\n", -ret);
1355 kfree(io_req);
1356 }
1357 return ret;
1358 }
1359
1360 static int queue_rw_req(struct blk_mq_hw_ctx *hctx, struct request *req)
1361 {
1362 struct req_iterator iter;
1363 struct bio_vec bvec;
1364 int ret;
1365 u64 off = (u64)blk_rq_pos(req) << SECTOR_SHIFT;
1366
1367 rq_for_each_segment(bvec, req, iter) {
1368 ret = ubd_queue_one_vec(hctx, req, off, &bvec);
1369 if (ret < 0)
1370 return ret;
1371 off += bvec.bv_len;
1372 }
1373 return 0;
1374 }
1375
1376 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
1377 const struct blk_mq_queue_data *bd)
1378 {
1379 struct ubd *ubd_dev = hctx->queue->queuedata;
1380 struct request *req = bd->rq;
1381 int ret = 0, res = BLK_STS_OK;
1382
1383 blk_mq_start_request(req);
1384
1385 spin_lock_irq(&ubd_dev->lock);
1386
1387 switch (req_op(req)) {
1388 /* operations with no lentgth/offset arguments */
1389 case REQ_OP_FLUSH:
1390 ret = ubd_queue_one_vec(hctx, req, 0, NULL);
1391 break;
1392 case REQ_OP_READ:
1393 case REQ_OP_WRITE:
1394 ret = queue_rw_req(hctx, req);
1395 break;
1396 case REQ_OP_DISCARD:
1397 case REQ_OP_WRITE_ZEROES:
1398 ret = ubd_queue_one_vec(hctx, req, (u64)blk_rq_pos(req) << 9, NULL);
1399 break;
1400 default:
1401 WARN_ON_ONCE(1);
1402 res = BLK_STS_NOTSUPP;
1403 }
1404
1405 spin_unlock_irq(&ubd_dev->lock);
1406
1407 if (ret < 0) {
1408 if (ret == -ENOMEM)
1409 res = BLK_STS_RESOURCE;
1410 else
1411 res = BLK_STS_DEV_RESOURCE;
1412 }
1413
1414 return res;
1415 }
1416
1417 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1418 {
1419 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1420
1421 geo->heads = 128;
1422 geo->sectors = 32;
1423 geo->cylinders = ubd_dev->size / (128 * 32 * 512);
1424 return 0;
1425 }
1426
1427 static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
1428 unsigned int cmd, unsigned long arg)
1429 {
1430 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1431 u16 ubd_id[ATA_ID_WORDS];
1432
1433 switch (cmd) {
1434 struct cdrom_volctrl volume;
1435 case HDIO_GET_IDENTITY:
1436 memset(&ubd_id, 0, ATA_ID_WORDS * 2);
1437 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512);
1438 ubd_id[ATA_ID_HEADS] = 128;
1439 ubd_id[ATA_ID_SECTORS] = 32;
1440 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1441 sizeof(ubd_id)))
1442 return -EFAULT;
1443 return 0;
1444
1445 case CDROMVOLREAD:
1446 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1447 return -EFAULT;
1448 volume.channel0 = 255;
1449 volume.channel1 = 255;
1450 volume.channel2 = 255;
1451 volume.channel3 = 255;
1452 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1453 return -EFAULT;
1454 return 0;
1455 }
1456 return -EINVAL;
1457 }
1458
1459 static int map_error(int error_code)
1460 {
1461 switch (error_code) {
1462 case 0:
1463 return BLK_STS_OK;
1464 case ENOSYS:
1465 case EOPNOTSUPP:
1466 return BLK_STS_NOTSUPP;
1467 case ENOSPC:
1468 return BLK_STS_NOSPC;
1469 }
1470 return BLK_STS_IOERR;
1471 }
1472
1473 /*
1474 * Everything from here onwards *IS NOT PART OF THE KERNEL*
1475 *
1476 * The following functions are part of UML hypervisor code.
1477 * All functions from here onwards are executed as a helper
1478 * thread and are not allowed to execute any kernel functions.
1479 *
1480 * Any communication must occur strictly via shared memory and IPC.
1481 *
1482 * Do not add printks, locks, kernel memory operations, etc - it
1483 * will result in unpredictable behaviour and/or crashes.
1484 */
1485
1486 static int update_bitmap(struct io_thread_req *req)
1487 {
1488 int n;
1489
1490 if(req->cow_offset == -1)
1491 return map_error(0);
1492
1493 n = os_pwrite_file(req->fds[1], &req->bitmap_words,
1494 sizeof(req->bitmap_words), req->cow_offset);
1495 if (n != sizeof(req->bitmap_words))
1496 return map_error(-n);
1497
1498 return map_error(0);
1499 }
1500
1501 static void do_io(struct io_thread_req *req)
1502 {
1503 char *buf = NULL;
1504 unsigned long len;
1505 int n, nsectors, start, end, bit;
1506 __u64 off;
1507
1508 /* FLUSH is really a special case, we cannot "case" it with others */
1509
1510 if (req_op(req->req) == REQ_OP_FLUSH) {
1511 /* fds[0] is always either the rw image or our cow file */
1512 req->error = map_error(-os_sync_file(req->fds[0]));
1513 return;
1514 }
1515
1516 nsectors = req->length / req->sectorsize;
1517 start = 0;
1518 do {
1519 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask);
1520 end = start;
1521 while((end < nsectors) &&
1522 (ubd_test_bit(end, (unsigned char *)
1523 &req->sector_mask) == bit))
1524 end++;
1525
1526 off = req->offset + req->offsets[bit] +
1527 start * req->sectorsize;
1528 len = (end - start) * req->sectorsize;
1529 if (req->buffer != NULL)
1530 buf = &req->buffer[start * req->sectorsize];
1531
1532 switch (req_op(req->req)) {
1533 case REQ_OP_READ:
1534 n = 0;
1535 do {
1536 buf = &buf[n];
1537 len -= n;
1538 n = os_pread_file(req->fds[bit], buf, len, off);
1539 if (n < 0) {
1540 req->error = map_error(-n);
1541 return;
1542 }
1543 } while((n < len) && (n != 0));
1544 if (n < len) memset(&buf[n], 0, len - n);
1545 break;
1546 case REQ_OP_WRITE:
1547 n = os_pwrite_file(req->fds[bit], buf, len, off);
1548 if(n != len){
1549 req->error = map_error(-n);
1550 return;
1551 }
1552 break;
1553 case REQ_OP_DISCARD:
1554 case REQ_OP_WRITE_ZEROES:
1555 n = os_falloc_punch(req->fds[bit], off, len);
1556 if (n) {
1557 req->error = map_error(-n);
1558 return;
1559 }
1560 break;
1561 default:
1562 WARN_ON_ONCE(1);
1563 req->error = BLK_STS_NOTSUPP;
1564 return;
1565 }
1566
1567 start = end;
1568 } while(start < nsectors);
1569
1570 req->error = update_bitmap(req);
1571 }
1572
1573 /* Changed in start_io_thread, which is serialized by being called only
1574 * from ubd_init, which is an initcall.
1575 */
1576 int kernel_fd = -1;
1577
1578 /* Only changed by the io thread. XXX: currently unused. */
1579 static int io_count = 0;
1580
1581 int io_thread(void *arg)
1582 {
1583 int n, count, written, res;
1584
1585 os_fix_helper_signals();
1586
1587 while(1){
1588 n = bulk_req_safe_read(
1589 kernel_fd,
1590 io_req_buffer,
1591 &io_remainder,
1592 &io_remainder_size,
1593 UBD_REQ_BUFFER_SIZE
1594 );
1595 if (n <= 0) {
1596 if (n == -EAGAIN)
1597 ubd_read_poll(-1);
1598
1599 continue;
1600 }
1601
1602 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
1603 io_count++;
1604 do_io((*io_req_buffer)[count]);
1605 }
1606
1607 written = 0;
1608
1609 do {
1610 res = os_write_file(kernel_fd,
1611 ((char *) io_req_buffer) + written,
1612 n - written);
1613 if (res >= 0) {
1614 written += res;
1615 }
1616 if (written < n) {
1617 ubd_write_poll(-1);
1618 }
1619 } while (written < n);
1620 }
1621
1622 return 0;
1623 }
Linux with added FPC-III support