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io_uring: ensure finish_wait() is always called in __io_uring_task_cancel()
[linux/fpc-iii.git] / arch / um / drivers / ubd_kern.c
blob13b1fe694b90494dab3d8034709172fbe9125616
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_desc {
51 char *buffer;
52 unsigned long length;
53 unsigned long sector_mask;
54 unsigned long long cow_offset;
55 unsigned long bitmap_words[2];
56 };
57
58 struct io_thread_req {
59 struct request *req;
60 int fds[2];
61 unsigned long offsets[2];
62 unsigned long long offset;
63 int sectorsize;
64 int error;
65
66 int desc_cnt;
67 /* io_desc has to be the last element of the struct */
68 struct io_desc io_desc[];
69 };
70
71
72 static struct io_thread_req * (*irq_req_buffer)[];
73 static struct io_thread_req *irq_remainder;
74 static int irq_remainder_size;
75
76 static struct io_thread_req * (*io_req_buffer)[];
77 static struct io_thread_req *io_remainder;
78 static int io_remainder_size;
79
80
81
82 static inline int ubd_test_bit(__u64 bit, unsigned char *data)
83 {
84 __u64 n;
85 int bits, off;
86
87 bits = sizeof(data[0]) * 8;
88 n = bit / bits;
89 off = bit % bits;
90 return (data[n] & (1 << off)) != 0;
91 }
92
93 static inline void ubd_set_bit(__u64 bit, unsigned char *data)
94 {
95 __u64 n;
96 int bits, off;
97
98 bits = sizeof(data[0]) * 8;
99 n = bit / bits;
100 off = bit % bits;
101 data[n] |= (1 << off);
102 }
103 /*End stuff from ubd_user.h*/
104
105 #define DRIVER_NAME "uml-blkdev"
106
107 static DEFINE_MUTEX(ubd_lock);
108 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
109
110 static int ubd_open(struct block_device *bdev, fmode_t mode);
111 static void ubd_release(struct gendisk *disk, fmode_t mode);
112 static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
113 unsigned int cmd, unsigned long arg);
114 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
115
116 #define MAX_DEV (16)
117
118 static const struct block_device_operations ubd_blops = {
119 .owner = THIS_MODULE,
120 .open = ubd_open,
121 .release = ubd_release,
122 .ioctl = ubd_ioctl,
123 .compat_ioctl = blkdev_compat_ptr_ioctl,
124 .getgeo = ubd_getgeo,
125 };
126
127 /* Protected by ubd_lock */
128 static int fake_major = UBD_MAJOR;
129 static struct gendisk *ubd_gendisk[MAX_DEV];
130 static struct gendisk *fake_gendisk[MAX_DEV];
131
132 #ifdef CONFIG_BLK_DEV_UBD_SYNC
133 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
134 .cl = 1 })
135 #else
136 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
137 .cl = 1 })
138 #endif
139 static struct openflags global_openflags = OPEN_FLAGS;
140
141 struct cow {
142 /* backing file name */
143 char *file;
144 /* backing file fd */
145 int fd;
146 unsigned long *bitmap;
147 unsigned long bitmap_len;
148 int bitmap_offset;
149 int data_offset;
150 };
151
152 #define MAX_SG 64
153
154 struct ubd {
155 /* name (and fd, below) of the file opened for writing, either the
156 * backing or the cow file. */
157 char *file;
158 char *serial;
159 int count;
160 int fd;
161 __u64 size;
162 struct openflags boot_openflags;
163 struct openflags openflags;
164 unsigned shared:1;
165 unsigned no_cow:1;
166 unsigned no_trim:1;
167 struct cow cow;
168 struct platform_device pdev;
169 struct request_queue *queue;
170 struct blk_mq_tag_set tag_set;
171 spinlock_t lock;
172 };
173
174 #define DEFAULT_COW { \
175 .file = NULL, \
176 .fd = -1, \
177 .bitmap = NULL, \
178 .bitmap_offset = 0, \
179 .data_offset = 0, \
180 }
181
182 #define DEFAULT_UBD { \
183 .file = NULL, \
184 .serial = NULL, \
185 .count = 0, \
186 .fd = -1, \
187 .size = -1, \
188 .boot_openflags = OPEN_FLAGS, \
189 .openflags = OPEN_FLAGS, \
190 .no_cow = 0, \
191 .no_trim = 0, \
192 .shared = 0, \
193 .cow = DEFAULT_COW, \
194 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
195 }
196
197 /* Protected by ubd_lock */
198 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
199
200 /* Only changed by fake_ide_setup which is a setup */
201 static int fake_ide = 0;
202 static struct proc_dir_entry *proc_ide_root = NULL;
203 static struct proc_dir_entry *proc_ide = NULL;
204
205 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
206 const struct blk_mq_queue_data *bd);
207
208 static void make_proc_ide(void)
209 {
210 proc_ide_root = proc_mkdir("ide", NULL);
211 proc_ide = proc_mkdir("ide0", proc_ide_root);
212 }
213
214 static int fake_ide_media_proc_show(struct seq_file *m, void *v)
215 {
216 seq_puts(m, "disk\n");
217 return 0;
218 }
219
220 static void make_ide_entries(const char *dev_name)
221 {
222 struct proc_dir_entry *dir, *ent;
223 char name[64];
224
225 if(proc_ide_root == NULL) make_proc_ide();
226
227 dir = proc_mkdir(dev_name, proc_ide);
228 if(!dir) return;
229
230 ent = proc_create_single("media", S_IRUGO, dir,
231 fake_ide_media_proc_show);
232 if(!ent) return;
233 snprintf(name, sizeof(name), "ide0/%s", dev_name);
234 proc_symlink(dev_name, proc_ide_root, name);
235 }
236
237 static int fake_ide_setup(char *str)
238 {
239 fake_ide = 1;
240 return 1;
241 }
242
243 __setup("fake_ide", fake_ide_setup);
244
245 __uml_help(fake_ide_setup,
246 "fake_ide\n"
247 " Create ide0 entries that map onto ubd devices.\n\n"
248 );
249
250 static int parse_unit(char **ptr)
251 {
252 char *str = *ptr, *end;
253 int n = -1;
254
255 if(isdigit(*str)) {
256 n = simple_strtoul(str, &end, 0);
257 if(end == str)
258 return -1;
259 *ptr = end;
260 }
261 else if (('a' <= *str) && (*str <= 'z')) {
262 n = *str - 'a';
263 str++;
264 *ptr = str;
265 }
266 return n;
267 }
268
269 /* If *index_out == -1 at exit, the passed option was a general one;
270 * otherwise, the str pointer is used (and owned) inside ubd_devs array, so it
271 * should not be freed on exit.
272 */
273 static int ubd_setup_common(char *str, int *index_out, char **error_out)
274 {
275 struct ubd *ubd_dev;
276 struct openflags flags = global_openflags;
277 char *file, *backing_file, *serial;
278 int n, err = 0, i;
279
280 if(index_out) *index_out = -1;
281 n = *str;
282 if(n == '='){
283 char *end;
284 int major;
285
286 str++;
287 if(!strcmp(str, "sync")){
288 global_openflags = of_sync(global_openflags);
289 return err;
290 }
291
292 err = -EINVAL;
293 major = simple_strtoul(str, &end, 0);
294 if((*end != '\0') || (end == str)){
295 *error_out = "Didn't parse major number";
296 return err;
297 }
298
299 mutex_lock(&ubd_lock);
300 if (fake_major != UBD_MAJOR) {
301 *error_out = "Can't assign a fake major twice";
302 goto out1;
303 }
304
305 fake_major = major;
306
307 printk(KERN_INFO "Setting extra ubd major number to %d\n",
308 major);
309 err = 0;
310 out1:
311 mutex_unlock(&ubd_lock);
312 return err;
313 }
314
315 n = parse_unit(&str);
316 if(n < 0){
317 *error_out = "Couldn't parse device number";
318 return -EINVAL;
319 }
320 if(n >= MAX_DEV){
321 *error_out = "Device number out of range";
322 return 1;
323 }
324
325 err = -EBUSY;
326 mutex_lock(&ubd_lock);
327
328 ubd_dev = &ubd_devs[n];
329 if(ubd_dev->file != NULL){
330 *error_out = "Device is already configured";
331 goto out;
332 }
333
334 if (index_out)
335 *index_out = n;
336
337 err = -EINVAL;
338 for (i = 0; i < sizeof("rscdt="); i++) {
339 switch (*str) {
340 case 'r':
341 flags.w = 0;
342 break;
343 case 's':
344 flags.s = 1;
345 break;
346 case 'd':
347 ubd_dev->no_cow = 1;
348 break;
349 case 'c':
350 ubd_dev->shared = 1;
351 break;
352 case 't':
353 ubd_dev->no_trim = 1;
354 break;
355 case '=':
356 str++;
357 goto break_loop;
358 default:
359 *error_out = "Expected '=' or flag letter "
360 "(r, s, c, t or d)";
361 goto out;
362 }
363 str++;
364 }
365
366 if (*str == '=')
367 *error_out = "Too many flags specified";
368 else
369 *error_out = "Missing '='";
370 goto out;
371
372 break_loop:
373 file = strsep(&str, ",:");
374 if (*file == '\0')
375 file = NULL;
376
377 backing_file = strsep(&str, ",:");
378 if (*backing_file == '\0')
379 backing_file = NULL;
380
381 serial = strsep(&str, ",:");
382 if (*serial == '\0')
383 serial = NULL;
384
385 if (backing_file && ubd_dev->no_cow) {
386 *error_out = "Can't specify both 'd' and a cow file";
387 goto out;
388 }
389
390 err = 0;
391 ubd_dev->file = file;
392 ubd_dev->cow.file = backing_file;
393 ubd_dev->serial = serial;
394 ubd_dev->boot_openflags = flags;
395 out:
396 mutex_unlock(&ubd_lock);
397 return err;
398 }
399
400 static int ubd_setup(char *str)
401 {
402 char *error;
403 int err;
404
405 err = ubd_setup_common(str, NULL, &error);
406 if(err)
407 printk(KERN_ERR "Failed to initialize device with \"%s\" : "
408 "%s\n", str, error);
409 return 1;
410 }
411
412 __setup("ubd", ubd_setup);
413 __uml_help(ubd_setup,
414 "ubd<n><flags>=<filename>[(:|,)<filename2>][(:|,)<serial>]\n"
415 " This is used to associate a device with a file in the underlying\n"
416 " filesystem. When specifying two filenames, the first one is the\n"
417 " COW name and the second is the backing file name. As separator you can\n"
418 " use either a ':' or a ',': the first one allows writing things like;\n"
419 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
420 " while with a ',' the shell would not expand the 2nd '~'.\n"
421 " When using only one filename, UML will detect whether to treat it like\n"
422 " a COW file or a backing file. To override this detection, add the 'd'\n"
423 " flag:\n"
424 " ubd0d=BackingFile\n"
425 " Usually, there is a filesystem in the file, but \n"
426 " that's not required. Swap devices containing swap files can be\n"
427 " specified like this. Also, a file which doesn't contain a\n"
428 " filesystem can have its contents read in the virtual \n"
429 " machine by running 'dd' on the device. <n> must be in the range\n"
430 " 0 to 7. Appending an 'r' to the number will cause that device\n"
431 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
432 " an 's' will cause data to be written to disk on the host immediately.\n"
433 " 'c' will cause the device to be treated as being shared between multiple\n"
434 " UMLs and file locking will be turned off - this is appropriate for a\n"
435 " cluster filesystem and inappropriate at almost all other times.\n\n"
436 " 't' will disable trim/discard support on the device (enabled by default).\n\n"
437 " An optional device serial number can be exposed using the serial parameter\n"
438 " on the cmdline which is exposed as a sysfs entry. This is particularly\n"
439 " useful when a unique number should be given to the device. Note when\n"
440 " specifying a label, the filename2 must be also presented. It can be\n"
441 " an empty string, in which case the backing file is not used:\n"
442 " ubd0=File,,Serial\n"
443 );
444
445 static int udb_setup(char *str)
446 {
447 printk("udb%s specified on command line is almost certainly a ubd -> "
448 "udb TYPO\n", str);
449 return 1;
450 }
451
452 __setup("udb", udb_setup);
453 __uml_help(udb_setup,
454 "udb\n"
455 " This option is here solely to catch ubd -> udb typos, which can be\n"
456 " to impossible to catch visually unless you specifically look for\n"
457 " them. The only result of any option starting with 'udb' is an error\n"
458 " in the boot output.\n\n"
459 );
460
461 /* Only changed by ubd_init, which is an initcall. */
462 static int thread_fd = -1;
463
464 /* Function to read several request pointers at a time
465 * handling fractional reads if (and as) needed
466 */
467
468 static int bulk_req_safe_read(
469 int fd,
470 struct io_thread_req * (*request_buffer)[],
471 struct io_thread_req **remainder,
472 int *remainder_size,
473 int max_recs
474 )
475 {
476 int n = 0;
477 int res = 0;
478
479 if (*remainder_size > 0) {
480 memmove(
481 (char *) request_buffer,
482 (char *) remainder, *remainder_size
483 );
484 n = *remainder_size;
485 }
486
487 res = os_read_file(
488 fd,
489 ((char *) request_buffer) + *remainder_size,
490 sizeof(struct io_thread_req *)*max_recs
491 - *remainder_size
492 );
493 if (res > 0) {
494 n += res;
495 if ((n % sizeof(struct io_thread_req *)) > 0) {
496 /*
497 * Read somehow returned not a multiple of dword
498 * theoretically possible, but never observed in the
499 * wild, so read routine must be able to handle it
500 */
501 *remainder_size = n % sizeof(struct io_thread_req *);
502 WARN(*remainder_size > 0, "UBD IPC read returned a partial result");
503 memmove(
504 remainder,
505 ((char *) request_buffer) +
506 (n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *),
507 *remainder_size
508 );
509 n = n - *remainder_size;
510 }
511 } else {
512 n = res;
513 }
514 return n;
515 }
516
517 /* Called without dev->lock held, and only in interrupt context. */
518 static void ubd_handler(void)
519 {
520 int n;
521 int count;
522
523 while(1){
524 n = bulk_req_safe_read(
525 thread_fd,
526 irq_req_buffer,
527 &irq_remainder,
528 &irq_remainder_size,
529 UBD_REQ_BUFFER_SIZE
530 );
531 if (n < 0) {
532 if(n == -EAGAIN)
533 break;
534 printk(KERN_ERR "spurious interrupt in ubd_handler, "
535 "err = %d\n", -n);
536 return;
537 }
538 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
539 struct io_thread_req *io_req = (*irq_req_buffer)[count];
540
541 if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
542 blk_queue_max_discard_sectors(io_req->req->q, 0);
543 blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
544 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q);
545 }
546 blk_mq_end_request(io_req->req, io_req->error);
547 kfree(io_req);
548 }
549 }
550 }
551
552 static irqreturn_t ubd_intr(int irq, void *dev)
553 {
554 ubd_handler();
555 return IRQ_HANDLED;
556 }
557
558 /* Only changed by ubd_init, which is an initcall. */
559 static int io_pid = -1;
560
561 static void kill_io_thread(void)
562 {
563 if(io_pid != -1)
564 os_kill_process(io_pid, 1);
565 }
566
567 __uml_exitcall(kill_io_thread);
568
569 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
570 {
571 char *file;
572 int fd;
573 int err;
574
575 __u32 version;
576 __u32 align;
577 char *backing_file;
578 time64_t mtime;
579 unsigned long long size;
580 int sector_size;
581 int bitmap_offset;
582
583 if (ubd_dev->file && ubd_dev->cow.file) {
584 file = ubd_dev->cow.file;
585
586 goto out;
587 }
588
589 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0);
590 if (fd < 0)
591 return fd;
592
593 err = read_cow_header(file_reader, &fd, &version, &backing_file, \
594 &mtime, &size, &sector_size, &align, &bitmap_offset);
595 os_close_file(fd);
596
597 if(err == -EINVAL)
598 file = ubd_dev->file;
599 else
600 file = backing_file;
601
602 out:
603 return os_file_size(file, size_out);
604 }
605
606 static int read_cow_bitmap(int fd, void *buf, int offset, int len)
607 {
608 int err;
609
610 err = os_pread_file(fd, buf, len, offset);
611 if (err < 0)
612 return err;
613
614 return 0;
615 }
616
617 static int backing_file_mismatch(char *file, __u64 size, time64_t mtime)
618 {
619 time64_t modtime;
620 unsigned long long actual;
621 int err;
622
623 err = os_file_modtime(file, &modtime);
624 if (err < 0) {
625 printk(KERN_ERR "Failed to get modification time of backing "
626 "file \"%s\", err = %d\n", file, -err);
627 return err;
628 }
629
630 err = os_file_size(file, &actual);
631 if (err < 0) {
632 printk(KERN_ERR "Failed to get size of backing file \"%s\", "
633 "err = %d\n", file, -err);
634 return err;
635 }
636
637 if (actual != size) {
638 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
639 * the typecast.*/
640 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header "
641 "vs backing file\n", (unsigned long long) size, actual);
642 return -EINVAL;
643 }
644 if (modtime != mtime) {
645 printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs "
646 "backing file\n", mtime, modtime);
647 return -EINVAL;
648 }
649 return 0;
650 }
651
652 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
653 {
654 struct uml_stat buf1, buf2;
655 int err;
656
657 if (from_cmdline == NULL)
658 return 0;
659 if (!strcmp(from_cmdline, from_cow))
660 return 0;
661
662 err = os_stat_file(from_cmdline, &buf1);
663 if (err < 0) {
664 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline,
665 -err);
666 return 0;
667 }
668 err = os_stat_file(from_cow, &buf2);
669 if (err < 0) {
670 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow,
671 -err);
672 return 1;
673 }
674 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
675 return 0;
676
677 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, "
678 "\"%s\" specified in COW header of \"%s\"\n",
679 from_cmdline, from_cow, cow);
680 return 1;
681 }
682
683 static int open_ubd_file(char *file, struct openflags *openflags, int shared,
684 char **backing_file_out, int *bitmap_offset_out,
685 unsigned long *bitmap_len_out, int *data_offset_out,
686 int *create_cow_out)
687 {
688 time64_t mtime;
689 unsigned long long size;
690 __u32 version, align;
691 char *backing_file;
692 int fd, err, sectorsize, asked_switch, mode = 0644;
693
694 fd = os_open_file(file, *openflags, mode);
695 if (fd < 0) {
696 if ((fd == -ENOENT) && (create_cow_out != NULL))
697 *create_cow_out = 1;
698 if (!openflags->w ||
699 ((fd != -EROFS) && (fd != -EACCES)))
700 return fd;
701 openflags->w = 0;
702 fd = os_open_file(file, *openflags, mode);
703 if (fd < 0)
704 return fd;
705 }
706
707 if (shared)
708 printk(KERN_INFO "Not locking \"%s\" on the host\n", file);
709 else {
710 err = os_lock_file(fd, openflags->w);
711 if (err < 0) {
712 printk(KERN_ERR "Failed to lock '%s', err = %d\n",
713 file, -err);
714 goto out_close;
715 }
716 }
717
718 /* Successful return case! */
719 if (backing_file_out == NULL)
720 return fd;
721
722 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
723 &size, &sectorsize, &align, bitmap_offset_out);
724 if (err && (*backing_file_out != NULL)) {
725 printk(KERN_ERR "Failed to read COW header from COW file "
726 "\"%s\", errno = %d\n", file, -err);
727 goto out_close;
728 }
729 if (err)
730 return fd;
731
732 asked_switch = path_requires_switch(*backing_file_out, backing_file,
733 file);
734
735 /* Allow switching only if no mismatch. */
736 if (asked_switch && !backing_file_mismatch(*backing_file_out, size,
737 mtime)) {
738 printk(KERN_ERR "Switching backing file to '%s'\n",
739 *backing_file_out);
740 err = write_cow_header(file, fd, *backing_file_out,
741 sectorsize, align, &size);
742 if (err) {
743 printk(KERN_ERR "Switch failed, errno = %d\n", -err);
744 goto out_close;
745 }
746 } else {
747 *backing_file_out = backing_file;
748 err = backing_file_mismatch(*backing_file_out, size, mtime);
749 if (err)
750 goto out_close;
751 }
752
753 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
754 bitmap_len_out, data_offset_out);
755
756 return fd;
757 out_close:
758 os_close_file(fd);
759 return err;
760 }
761
762 static int create_cow_file(char *cow_file, char *backing_file,
763 struct openflags flags,
764 int sectorsize, int alignment, int *bitmap_offset_out,
765 unsigned long *bitmap_len_out, int *data_offset_out)
766 {
767 int err, fd;
768
769 flags.c = 1;
770 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL);
771 if (fd < 0) {
772 err = fd;
773 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n",
774 cow_file, -err);
775 goto out;
776 }
777
778 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
779 bitmap_offset_out, bitmap_len_out,
780 data_offset_out);
781 if (!err)
782 return fd;
783 os_close_file(fd);
784 out:
785 return err;
786 }
787
788 static void ubd_close_dev(struct ubd *ubd_dev)
789 {
790 os_close_file(ubd_dev->fd);
791 if(ubd_dev->cow.file == NULL)
792 return;
793
794 os_close_file(ubd_dev->cow.fd);
795 vfree(ubd_dev->cow.bitmap);
796 ubd_dev->cow.bitmap = NULL;
797 }
798
799 static int ubd_open_dev(struct ubd *ubd_dev)
800 {
801 struct openflags flags;
802 char **back_ptr;
803 int err, create_cow, *create_ptr;
804 int fd;
805
806 ubd_dev->openflags = ubd_dev->boot_openflags;
807 create_cow = 0;
808 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
809 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;
810
811 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
812 back_ptr, &ubd_dev->cow.bitmap_offset,
813 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
814 create_ptr);
815
816 if((fd == -ENOENT) && create_cow){
817 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
818 ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE,
819 &ubd_dev->cow.bitmap_offset,
820 &ubd_dev->cow.bitmap_len,
821 &ubd_dev->cow.data_offset);
822 if(fd >= 0){
823 printk(KERN_INFO "Creating \"%s\" as COW file for "
824 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
825 }
826 }
827
828 if(fd < 0){
829 printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
830 -fd);
831 return fd;
832 }
833 ubd_dev->fd = fd;
834
835 if(ubd_dev->cow.file != NULL){
836 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long));
837
838 err = -ENOMEM;
839 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
840 if(ubd_dev->cow.bitmap == NULL){
841 printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
842 goto error;
843 }
844 flush_tlb_kernel_vm();
845
846 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
847 ubd_dev->cow.bitmap_offset,
848 ubd_dev->cow.bitmap_len);
849 if(err < 0)
850 goto error;
851
852 flags = ubd_dev->openflags;
853 flags.w = 0;
854 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
855 NULL, NULL, NULL, NULL);
856 if(err < 0) goto error;
857 ubd_dev->cow.fd = err;
858 }
859 if (ubd_dev->no_trim == 0) {
860 ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
861 ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE;
862 blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
863 blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
864 blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue);
865 }
866 blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
867 return 0;
868 error:
869 os_close_file(ubd_dev->fd);
870 return err;
871 }
872
873 static void ubd_device_release(struct device *dev)
874 {
875 struct ubd *ubd_dev = dev_get_drvdata(dev);
876
877 blk_cleanup_queue(ubd_dev->queue);
878 blk_mq_free_tag_set(&ubd_dev->tag_set);
879 *ubd_dev = ((struct ubd) DEFAULT_UBD);
880 }
881
882 static ssize_t serial_show(struct device *dev,
883 struct device_attribute *attr, char *buf)
884 {
885 struct gendisk *disk = dev_to_disk(dev);
886 struct ubd *ubd_dev = disk->private_data;
887
888 if (!ubd_dev)
889 return 0;
890
891 return sprintf(buf, "%s", ubd_dev->serial);
892 }
893
894 static DEVICE_ATTR_RO(serial);
895
896 static struct attribute *ubd_attrs[] = {
897 &dev_attr_serial.attr,
898 NULL,
899 };
900
901 static umode_t ubd_attrs_are_visible(struct kobject *kobj,
902 struct attribute *a, int n)
903 {
904 return a->mode;
905 }
906
907 static const struct attribute_group ubd_attr_group = {
908 .attrs = ubd_attrs,
909 .is_visible = ubd_attrs_are_visible,
910 };
911
912 static const struct attribute_group *ubd_attr_groups[] = {
913 &ubd_attr_group,
914 NULL,
915 };
916
917 static int ubd_disk_register(int major, u64 size, int unit,
918 struct gendisk **disk_out)
919 {
920 struct device *parent = NULL;
921 struct gendisk *disk;
922
923 disk = alloc_disk(1 << UBD_SHIFT);
924 if(disk == NULL)
925 return -ENOMEM;
926
927 disk->major = major;
928 disk->first_minor = unit << UBD_SHIFT;
929 disk->fops = &ubd_blops;
930 set_capacity(disk, size / 512);
931 if (major == UBD_MAJOR)
932 sprintf(disk->disk_name, "ubd%c", 'a' + unit);
933 else
934 sprintf(disk->disk_name, "ubd_fake%d", unit);
935
936 /* sysfs register (not for ide fake devices) */
937 if (major == UBD_MAJOR) {
938 ubd_devs[unit].pdev.id = unit;
939 ubd_devs[unit].pdev.name = DRIVER_NAME;
940 ubd_devs[unit].pdev.dev.release = ubd_device_release;
941 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
942 platform_device_register(&ubd_devs[unit].pdev);
943 parent = &ubd_devs[unit].pdev.dev;
944 }
945
946 disk->private_data = &ubd_devs[unit];
947 disk->queue = ubd_devs[unit].queue;
948 device_add_disk(parent, disk, ubd_attr_groups);
949
950 *disk_out = disk;
951 return 0;
952 }
953
954 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
955
956 static const struct blk_mq_ops ubd_mq_ops = {
957 .queue_rq = ubd_queue_rq,
958 };
959
960 static int ubd_add(int n, char **error_out)
961 {
962 struct ubd *ubd_dev = &ubd_devs[n];
963 int err = 0;
964
965 if(ubd_dev->file == NULL)
966 goto out;
967
968 err = ubd_file_size(ubd_dev, &ubd_dev->size);
969 if(err < 0){
970 *error_out = "Couldn't determine size of device's file";
971 goto out;
972 }
973
974 ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
975
976 ubd_dev->tag_set.ops = &ubd_mq_ops;
977 ubd_dev->tag_set.queue_depth = 64;
978 ubd_dev->tag_set.numa_node = NUMA_NO_NODE;
979 ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
980 ubd_dev->tag_set.driver_data = ubd_dev;
981 ubd_dev->tag_set.nr_hw_queues = 1;
982
983 err = blk_mq_alloc_tag_set(&ubd_dev->tag_set);
984 if (err)
985 goto out;
986
987 ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set);
988 if (IS_ERR(ubd_dev->queue)) {
989 err = PTR_ERR(ubd_dev->queue);
990 goto out_cleanup_tags;
991 }
992
993 ubd_dev->queue->queuedata = ubd_dev;
994 blk_queue_write_cache(ubd_dev->queue, true, false);
995
996 blk_queue_max_segments(ubd_dev->queue, MAX_SG);
997 blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1);
998 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
999 if(err){
1000 *error_out = "Failed to register device";
1001 goto out_cleanup_tags;
1002 }
1003
1004 if (fake_major != UBD_MAJOR)
1005 ubd_disk_register(fake_major, ubd_dev->size, n,
1006 &fake_gendisk[n]);
1007
1008 /*
1009 * Perhaps this should also be under the "if (fake_major)" above
1010 * using the fake_disk->disk_name
1011 */
1012 if (fake_ide)
1013 make_ide_entries(ubd_gendisk[n]->disk_name);
1014
1015 err = 0;
1016 out:
1017 return err;
1018
1019 out_cleanup_tags:
1020 blk_mq_free_tag_set(&ubd_dev->tag_set);
1021 if (!(IS_ERR(ubd_dev->queue)))
1022 blk_cleanup_queue(ubd_dev->queue);
1023 goto out;
1024 }
1025
1026 static int ubd_config(char *str, char **error_out)
1027 {
1028 int n, ret;
1029
1030 /* This string is possibly broken up and stored, so it's only
1031 * freed if ubd_setup_common fails, or if only general options
1032 * were set.
1033 */
1034 str = kstrdup(str, GFP_KERNEL);
1035 if (str == NULL) {
1036 *error_out = "Failed to allocate memory";
1037 return -ENOMEM;
1038 }
1039
1040 ret = ubd_setup_common(str, &n, error_out);
1041 if (ret)
1042 goto err_free;
1043
1044 if (n == -1) {
1045 ret = 0;
1046 goto err_free;
1047 }
1048
1049 mutex_lock(&ubd_lock);
1050 ret = ubd_add(n, error_out);
1051 if (ret)
1052 ubd_devs[n].file = NULL;
1053 mutex_unlock(&ubd_lock);
1054
1055 out:
1056 return ret;
1057
1058 err_free:
1059 kfree(str);
1060 goto out;
1061 }
1062
1063 static int ubd_get_config(char *name, char *str, int size, char **error_out)
1064 {
1065 struct ubd *ubd_dev;
1066 int n, len = 0;
1067
1068 n = parse_unit(&name);
1069 if((n >= MAX_DEV) || (n < 0)){
1070 *error_out = "ubd_get_config : device number out of range";
1071 return -1;
1072 }
1073
1074 ubd_dev = &ubd_devs[n];
1075 mutex_lock(&ubd_lock);
1076
1077 if(ubd_dev->file == NULL){
1078 CONFIG_CHUNK(str, size, len, "", 1);
1079 goto out;
1080 }
1081
1082 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0);
1083
1084 if(ubd_dev->cow.file != NULL){
1085 CONFIG_CHUNK(str, size, len, ",", 0);
1086 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1);
1087 }
1088 else CONFIG_CHUNK(str, size, len, "", 1);
1089
1090 out:
1091 mutex_unlock(&ubd_lock);
1092 return len;
1093 }
1094
1095 static int ubd_id(char **str, int *start_out, int *end_out)
1096 {
1097 int n;
1098
1099 n = parse_unit(str);
1100 *start_out = 0;
1101 *end_out = MAX_DEV - 1;
1102 return n;
1103 }
1104
1105 static int ubd_remove(int n, char **error_out)
1106 {
1107 struct gendisk *disk = ubd_gendisk[n];
1108 struct ubd *ubd_dev;
1109 int err = -ENODEV;
1110
1111 mutex_lock(&ubd_lock);
1112
1113 ubd_dev = &ubd_devs[n];
1114
1115 if(ubd_dev->file == NULL)
1116 goto out;
1117
1118 /* you cannot remove a open disk */
1119 err = -EBUSY;
1120 if(ubd_dev->count > 0)
1121 goto out;
1122
1123 ubd_gendisk[n] = NULL;
1124 if(disk != NULL){
1125 del_gendisk(disk);
1126 put_disk(disk);
1127 }
1128
1129 if(fake_gendisk[n] != NULL){
1130 del_gendisk(fake_gendisk[n]);
1131 put_disk(fake_gendisk[n]);
1132 fake_gendisk[n] = NULL;
1133 }
1134
1135 err = 0;
1136 platform_device_unregister(&ubd_dev->pdev);
1137 out:
1138 mutex_unlock(&ubd_lock);
1139 return err;
1140 }
1141
1142 /* All these are called by mconsole in process context and without
1143 * ubd-specific locks. The structure itself is const except for .list.
1144 */
1145 static struct mc_device ubd_mc = {
1146 .list = LIST_HEAD_INIT(ubd_mc.list),
1147 .name = "ubd",
1148 .config = ubd_config,
1149 .get_config = ubd_get_config,
1150 .id = ubd_id,
1151 .remove = ubd_remove,
1152 };
1153
1154 static int __init ubd_mc_init(void)
1155 {
1156 mconsole_register_dev(&ubd_mc);
1157 return 0;
1158 }
1159
1160 __initcall(ubd_mc_init);
1161
1162 static int __init ubd0_init(void)
1163 {
1164 struct ubd *ubd_dev = &ubd_devs[0];
1165
1166 mutex_lock(&ubd_lock);
1167 if(ubd_dev->file == NULL)
1168 ubd_dev->file = "root_fs";
1169 mutex_unlock(&ubd_lock);
1170
1171 return 0;
1172 }
1173
1174 __initcall(ubd0_init);
1175
1176 /* Used in ubd_init, which is an initcall */
1177 static struct platform_driver ubd_driver = {
1178 .driver = {
1179 .name = DRIVER_NAME,
1180 },
1181 };
1182
1183 static int __init ubd_init(void)
1184 {
1185 char *error;
1186 int i, err;
1187
1188 if (register_blkdev(UBD_MAJOR, "ubd"))
1189 return -1;
1190
1191 if (fake_major != UBD_MAJOR) {
1192 char name[sizeof("ubd_nnn\0")];
1193
1194 snprintf(name, sizeof(name), "ubd_%d", fake_major);
1195 if (register_blkdev(fake_major, "ubd"))
1196 return -1;
1197 }
1198
1199 irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1200 sizeof(struct io_thread_req *),
1201 GFP_KERNEL
1202 );
1203 irq_remainder = 0;
1204
1205 if (irq_req_buffer == NULL) {
1206 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1207 return -1;
1208 }
1209 io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
1210 sizeof(struct io_thread_req *),
1211 GFP_KERNEL
1212 );
1213
1214 io_remainder = 0;
1215
1216 if (io_req_buffer == NULL) {
1217 printk(KERN_ERR "Failed to initialize ubd buffering\n");
1218 return -1;
1219 }
1220 platform_driver_register(&ubd_driver);
1221 mutex_lock(&ubd_lock);
1222 for (i = 0; i < MAX_DEV; i++){
1223 err = ubd_add(i, &error);
1224 if(err)
1225 printk(KERN_ERR "Failed to initialize ubd device %d :"
1226 "%s\n", i, error);
1227 }
1228 mutex_unlock(&ubd_lock);
1229 return 0;
1230 }
1231
1232 late_initcall(ubd_init);
1233
1234 static int __init ubd_driver_init(void){
1235 unsigned long stack;
1236 int err;
1237
1238 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
1239 if(global_openflags.s){
1240 printk(KERN_INFO "ubd: Synchronous mode\n");
1241 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
1242 * enough. So use anyway the io thread. */
1243 }
1244 stack = alloc_stack(0);
1245 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
1246 &thread_fd);
1247 if(io_pid < 0){
1248 printk(KERN_ERR
1249 "ubd : Failed to start I/O thread (errno = %d) - "
1250 "falling back to synchronous I/O\n", -io_pid);
1251 io_pid = -1;
1252 return 0;
1253 }
1254 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
1255 0, "ubd", ubd_devs);
1256 if(err < 0)
1257 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
1258 return 0;
1259 }
1260
1261 device_initcall(ubd_driver_init);
1262
1263 static int ubd_open(struct block_device *bdev, fmode_t mode)
1264 {
1265 struct gendisk *disk = bdev->bd_disk;
1266 struct ubd *ubd_dev = disk->private_data;
1267 int err = 0;
1268
1269 mutex_lock(&ubd_mutex);
1270 if(ubd_dev->count == 0){
1271 err = ubd_open_dev(ubd_dev);
1272 if(err){
1273 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
1274 disk->disk_name, ubd_dev->file, -err);
1275 goto out;
1276 }
1277 }
1278 ubd_dev->count++;
1279 set_disk_ro(disk, !ubd_dev->openflags.w);
1280
1281 /* This should no more be needed. And it didn't work anyway to exclude
1282 * read-write remounting of filesystems.*/
1283 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){
1284 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
1285 err = -EROFS;
1286 }*/
1287 out:
1288 mutex_unlock(&ubd_mutex);
1289 return err;
1290 }
1291
1292 static void ubd_release(struct gendisk *disk, fmode_t mode)
1293 {
1294 struct ubd *ubd_dev = disk->private_data;
1295
1296 mutex_lock(&ubd_mutex);
1297 if(--ubd_dev->count == 0)
1298 ubd_close_dev(ubd_dev);
1299 mutex_unlock(&ubd_mutex);
1300 }
1301
1302 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
1303 __u64 *cow_offset, unsigned long *bitmap,
1304 __u64 bitmap_offset, unsigned long *bitmap_words,
1305 __u64 bitmap_len)
1306 {
1307 __u64 sector = io_offset >> SECTOR_SHIFT;
1308 int i, update_bitmap = 0;
1309
1310 for (i = 0; i < length >> SECTOR_SHIFT; i++) {
1311 if(cow_mask != NULL)
1312 ubd_set_bit(i, (unsigned char *) cow_mask);
1313 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1314 continue;
1315
1316 update_bitmap = 1;
1317 ubd_set_bit(sector + i, (unsigned char *) bitmap);
1318 }
1319
1320 if(!update_bitmap)
1321 return;
1322
1323 *cow_offset = sector / (sizeof(unsigned long) * 8);
1324
1325 /* This takes care of the case where we're exactly at the end of the
1326 * device, and *cow_offset + 1 is off the end. So, just back it up
1327 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1328 * for the original diagnosis.
1329 */
1330 if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
1331 sizeof(unsigned long)) - 1))
1332 (*cow_offset)--;
1333
1334 bitmap_words[0] = bitmap[*cow_offset];
1335 bitmap_words[1] = bitmap[*cow_offset + 1];
1336
1337 *cow_offset *= sizeof(unsigned long);
1338 *cow_offset += bitmap_offset;
1339 }
1340
1341 static void cowify_req(struct io_thread_req *req, struct io_desc *segment,
1342 unsigned long offset, unsigned long *bitmap,
1343 __u64 bitmap_offset, __u64 bitmap_len)
1344 {
1345 __u64 sector = offset >> SECTOR_SHIFT;
1346 int i;
1347
1348 if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT)
1349 panic("Operation too long");
1350
1351 if (req_op(req->req) == REQ_OP_READ) {
1352 for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) {
1353 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1354 ubd_set_bit(i, (unsigned char *)
1355 &segment->sector_mask);
1356 }
1357 } else {
1358 cowify_bitmap(offset, segment->length, &segment->sector_mask,
1359 &segment->cow_offset, bitmap, bitmap_offset,
1360 segment->bitmap_words, bitmap_len);
1361 }
1362 }
1363
1364 static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req,
1365 struct request *req)
1366 {
1367 struct bio_vec bvec;
1368 struct req_iterator iter;
1369 int i = 0;
1370 unsigned long byte_offset = io_req->offset;
1371 int op = req_op(req);
1372
1373 if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) {
1374 io_req->io_desc[0].buffer = NULL;
1375 io_req->io_desc[0].length = blk_rq_bytes(req);
1376 } else {
1377 rq_for_each_segment(bvec, req, iter) {
1378 BUG_ON(i >= io_req->desc_cnt);
1379
1380 io_req->io_desc[i].buffer =
1381 page_address(bvec.bv_page) + bvec.bv_offset;
1382 io_req->io_desc[i].length = bvec.bv_len;
1383 i++;
1384 }
1385 }
1386
1387 if (dev->cow.file) {
1388 for (i = 0; i < io_req->desc_cnt; i++) {
1389 cowify_req(io_req, &io_req->io_desc[i], byte_offset,
1390 dev->cow.bitmap, dev->cow.bitmap_offset,
1391 dev->cow.bitmap_len);
1392 byte_offset += io_req->io_desc[i].length;
1393 }
1394
1395 }
1396 }
1397
1398 static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req,
1399 int desc_cnt)
1400 {
1401 struct io_thread_req *io_req;
1402 int i;
1403
1404 io_req = kmalloc(sizeof(*io_req) +
1405 (desc_cnt * sizeof(struct io_desc)),
1406 GFP_ATOMIC);
1407 if (!io_req)
1408 return NULL;
1409
1410 io_req->req = req;
1411 if (dev->cow.file)
1412 io_req->fds[0] = dev->cow.fd;
1413 else
1414 io_req->fds[0] = dev->fd;
1415 io_req->error = 0;
1416 io_req->sectorsize = SECTOR_SIZE;
1417 io_req->fds[1] = dev->fd;
1418 io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT;
1419 io_req->offsets[0] = 0;
1420 io_req->offsets[1] = dev->cow.data_offset;
1421
1422 for (i = 0 ; i < desc_cnt; i++) {
1423 io_req->io_desc[i].sector_mask = 0;
1424 io_req->io_desc[i].cow_offset = -1;
1425 }
1426
1427 return io_req;
1428 }
1429
1430 static int ubd_submit_request(struct ubd *dev, struct request *req)
1431 {
1432 int segs = 0;
1433 struct io_thread_req *io_req;
1434 int ret;
1435 int op = req_op(req);
1436
1437 if (op == REQ_OP_FLUSH)
1438 segs = 0;
1439 else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD)
1440 segs = 1;
1441 else
1442 segs = blk_rq_nr_phys_segments(req);
1443
1444 io_req = ubd_alloc_req(dev, req, segs);
1445 if (!io_req)
1446 return -ENOMEM;
1447
1448 io_req->desc_cnt = segs;
1449 if (segs)
1450 ubd_map_req(dev, io_req, req);
1451
1452 ret = os_write_file(thread_fd, &io_req, sizeof(io_req));
1453 if (ret != sizeof(io_req)) {
1454 if (ret != -EAGAIN)
1455 pr_err("write to io thread failed: %d\n", -ret);
1456 kfree(io_req);
1457 }
1458 return ret;
1459 }
1460
1461 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
1462 const struct blk_mq_queue_data *bd)
1463 {
1464 struct ubd *ubd_dev = hctx->queue->queuedata;
1465 struct request *req = bd->rq;
1466 int ret = 0, res = BLK_STS_OK;
1467
1468 blk_mq_start_request(req);
1469
1470 spin_lock_irq(&ubd_dev->lock);
1471
1472 switch (req_op(req)) {
1473 case REQ_OP_FLUSH:
1474 case REQ_OP_READ:
1475 case REQ_OP_WRITE:
1476 case REQ_OP_DISCARD:
1477 case REQ_OP_WRITE_ZEROES:
1478 ret = ubd_submit_request(ubd_dev, req);
1479 break;
1480 default:
1481 WARN_ON_ONCE(1);
1482 res = BLK_STS_NOTSUPP;
1483 }
1484
1485 spin_unlock_irq(&ubd_dev->lock);
1486
1487 if (ret < 0) {
1488 if (ret == -ENOMEM)
1489 res = BLK_STS_RESOURCE;
1490 else
1491 res = BLK_STS_DEV_RESOURCE;
1492 }
1493
1494 return res;
1495 }
1496
1497 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1498 {
1499 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1500
1501 geo->heads = 128;
1502 geo->sectors = 32;
1503 geo->cylinders = ubd_dev->size / (128 * 32 * 512);
1504 return 0;
1505 }
1506
1507 static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
1508 unsigned int cmd, unsigned long arg)
1509 {
1510 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1511 u16 ubd_id[ATA_ID_WORDS];
1512
1513 switch (cmd) {
1514 struct cdrom_volctrl volume;
1515 case HDIO_GET_IDENTITY:
1516 memset(&ubd_id, 0, ATA_ID_WORDS * 2);
1517 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512);
1518 ubd_id[ATA_ID_HEADS] = 128;
1519 ubd_id[ATA_ID_SECTORS] = 32;
1520 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1521 sizeof(ubd_id)))
1522 return -EFAULT;
1523 return 0;
1524
1525 case CDROMVOLREAD:
1526 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1527 return -EFAULT;
1528 volume.channel0 = 255;
1529 volume.channel1 = 255;
1530 volume.channel2 = 255;
1531 volume.channel3 = 255;
1532 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1533 return -EFAULT;
1534 return 0;
1535 }
1536 return -EINVAL;
1537 }
1538
1539 static int map_error(int error_code)
1540 {
1541 switch (error_code) {
1542 case 0:
1543 return BLK_STS_OK;
1544 case ENOSYS:
1545 case EOPNOTSUPP:
1546 return BLK_STS_NOTSUPP;
1547 case ENOSPC:
1548 return BLK_STS_NOSPC;
1549 }
1550 return BLK_STS_IOERR;
1551 }
1552
1553 /*
1554 * Everything from here onwards *IS NOT PART OF THE KERNEL*
1555 *
1556 * The following functions are part of UML hypervisor code.
1557 * All functions from here onwards are executed as a helper
1558 * thread and are not allowed to execute any kernel functions.
1559 *
1560 * Any communication must occur strictly via shared memory and IPC.
1561 *
1562 * Do not add printks, locks, kernel memory operations, etc - it
1563 * will result in unpredictable behaviour and/or crashes.
1564 */
1565
1566 static int update_bitmap(struct io_thread_req *req, struct io_desc *segment)
1567 {
1568 int n;
1569
1570 if (segment->cow_offset == -1)
1571 return map_error(0);
1572
1573 n = os_pwrite_file(req->fds[1], &segment->bitmap_words,
1574 sizeof(segment->bitmap_words), segment->cow_offset);
1575 if (n != sizeof(segment->bitmap_words))
1576 return map_error(-n);
1577
1578 return map_error(0);
1579 }
1580
1581 static void do_io(struct io_thread_req *req, struct io_desc *desc)
1582 {
1583 char *buf = NULL;
1584 unsigned long len;
1585 int n, nsectors, start, end, bit;
1586 __u64 off;
1587
1588 /* FLUSH is really a special case, we cannot "case" it with others */
1589
1590 if (req_op(req->req) == REQ_OP_FLUSH) {
1591 /* fds[0] is always either the rw image or our cow file */
1592 req->error = map_error(-os_sync_file(req->fds[0]));
1593 return;
1594 }
1595
1596 nsectors = desc->length / req->sectorsize;
1597 start = 0;
1598 do {
1599 bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask);
1600 end = start;
1601 while((end < nsectors) &&
1602 (ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit))
1603 end++;
1604
1605 off = req->offset + req->offsets[bit] +
1606 start * req->sectorsize;
1607 len = (end - start) * req->sectorsize;
1608 if (desc->buffer != NULL)
1609 buf = &desc->buffer[start * req->sectorsize];
1610
1611 switch (req_op(req->req)) {
1612 case REQ_OP_READ:
1613 n = 0;
1614 do {
1615 buf = &buf[n];
1616 len -= n;
1617 n = os_pread_file(req->fds[bit], buf, len, off);
1618 if (n < 0) {
1619 req->error = map_error(-n);
1620 return;
1621 }
1622 } while((n < len) && (n != 0));
1623 if (n < len) memset(&buf[n], 0, len - n);
1624 break;
1625 case REQ_OP_WRITE:
1626 n = os_pwrite_file(req->fds[bit], buf, len, off);
1627 if(n != len){
1628 req->error = map_error(-n);
1629 return;
1630 }
1631 break;
1632 case REQ_OP_DISCARD:
1633 case REQ_OP_WRITE_ZEROES:
1634 n = os_falloc_punch(req->fds[bit], off, len);
1635 if (n) {
1636 req->error = map_error(-n);
1637 return;
1638 }
1639 break;
1640 default:
1641 WARN_ON_ONCE(1);
1642 req->error = BLK_STS_NOTSUPP;
1643 return;
1644 }
1645
1646 start = end;
1647 } while(start < nsectors);
1648
1649 req->offset += len;
1650 req->error = update_bitmap(req, desc);
1651 }
1652
1653 /* Changed in start_io_thread, which is serialized by being called only
1654 * from ubd_init, which is an initcall.
1655 */
1656 int kernel_fd = -1;
1657
1658 /* Only changed by the io thread. XXX: currently unused. */
1659 static int io_count = 0;
1660
1661 int io_thread(void *arg)
1662 {
1663 int n, count, written, res;
1664
1665 os_fix_helper_signals();
1666
1667 while(1){
1668 n = bulk_req_safe_read(
1669 kernel_fd,
1670 io_req_buffer,
1671 &io_remainder,
1672 &io_remainder_size,
1673 UBD_REQ_BUFFER_SIZE
1674 );
1675 if (n <= 0) {
1676 if (n == -EAGAIN)
1677 ubd_read_poll(-1);
1678
1679 continue;
1680 }
1681
1682 for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
1683 struct io_thread_req *req = (*io_req_buffer)[count];
1684 int i;
1685
1686 io_count++;
1687 for (i = 0; !req->error && i < req->desc_cnt; i++)
1688 do_io(req, &(req->io_desc[i]));
1689
1690 }
1691
1692 written = 0;
1693
1694 do {
1695 res = os_write_file(kernel_fd,
1696 ((char *) io_req_buffer) + written,
1697 n - written);
1698 if (res >= 0) {
1699 written += res;
1700 }
1701 if (written < n) {
1702 ubd_write_poll(-1);
1703 }
1704 } while (written < n);
1705 }
1706
1707 return 0;
1708 }
Linux with added FPC-III support