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[TG3]: Set minimal hw interrupt mitigation.
[linux-2.6/verdex.git] / arch / um / drivers / ubd_kern.c
blob9a56ff94308dff7a06a5b0fd5cff8ed3b14249ad
1 /*
2 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
4 */
5
6 /* 2001-09-28...2002-04-17
7 * Partition stuff by James_McMechan@hotmail.com
8 * old style ubd by setting UBD_SHIFT to 0
9 * 2002-09-27...2002-10-18 massive tinkering for 2.5
10 * partitions have changed in 2.5
11 * 2003-01-29 more tinkering for 2.5.59-1
12 * This should now address the sysfs problems and has
13 * the symlink for devfs to allow for booting with
14 * the common /dev/ubd/discX/... names rather than
15 * only /dev/ubdN/discN this version also has lots of
16 * clean ups preparing for ubd-many.
17 * James McMechan
18 */
19
20 #define MAJOR_NR UBD_MAJOR
21 #define UBD_SHIFT 4
22
23 #include "linux/config.h"
24 #include "linux/module.h"
25 #include "linux/blkdev.h"
26 #include "linux/hdreg.h"
27 #include "linux/init.h"
28 #include "linux/devfs_fs_kernel.h"
29 #include "linux/cdrom.h"
30 #include "linux/proc_fs.h"
31 #include "linux/ctype.h"
32 #include "linux/capability.h"
33 #include "linux/mm.h"
34 #include "linux/vmalloc.h"
35 #include "linux/blkpg.h"
36 #include "linux/genhd.h"
37 #include "linux/spinlock.h"
38 #include "asm/segment.h"
39 #include "asm/uaccess.h"
40 #include "asm/irq.h"
41 #include "asm/types.h"
42 #include "asm/tlbflush.h"
43 #include "user_util.h"
44 #include "mem_user.h"
45 #include "kern_util.h"
46 #include "kern.h"
47 #include "mconsole_kern.h"
48 #include "init.h"
49 #include "irq_user.h"
50 #include "irq_kern.h"
51 #include "ubd_user.h"
52 #include "2_5compat.h"
53 #include "os.h"
54 #include "mem.h"
55 #include "mem_kern.h"
56 #include "cow.h"
57
58 enum ubd_req { UBD_READ, UBD_WRITE, UBD_MMAP };
59
60 struct io_thread_req {
61 enum ubd_req op;
62 int fds[2];
63 unsigned long offsets[2];
64 unsigned long long offset;
65 unsigned long length;
66 char *buffer;
67 int sectorsize;
68 unsigned long sector_mask;
69 unsigned long long cow_offset;
70 unsigned long bitmap_words[2];
71 int map_fd;
72 unsigned long long map_offset;
73 int error;
74 };
75
76 extern int open_ubd_file(char *file, struct openflags *openflags,
77 char **backing_file_out, int *bitmap_offset_out,
78 unsigned long *bitmap_len_out, int *data_offset_out,
79 int *create_cow_out);
80 extern int create_cow_file(char *cow_file, char *backing_file,
81 struct openflags flags, int sectorsize,
82 int alignment, int *bitmap_offset_out,
83 unsigned long *bitmap_len_out,
84 int *data_offset_out);
85 extern int read_cow_bitmap(int fd, void *buf, int offset, int len);
86 extern void do_io(struct io_thread_req *req);
87
88 static inline int ubd_test_bit(__u64 bit, unsigned char *data)
89 {
90 __u64 n;
91 int bits, off;
92
93 bits = sizeof(data[0]) * 8;
94 n = bit / bits;
95 off = bit % bits;
96 return((data[n] & (1 << off)) != 0);
97 }
98
99 static inline void ubd_set_bit(__u64 bit, unsigned char *data)
100 {
101 __u64 n;
102 int bits, off;
103
104 bits = sizeof(data[0]) * 8;
105 n = bit / bits;
106 off = bit % bits;
107 data[n] |= (1 << off);
108 }
109 /*End stuff from ubd_user.h*/
110
111 #define DRIVER_NAME "uml-blkdev"
112
113 static DEFINE_SPINLOCK(ubd_io_lock);
114 static DEFINE_SPINLOCK(ubd_lock);
115
116 static void (*do_ubd)(void);
117
118 static int ubd_open(struct inode * inode, struct file * filp);
119 static int ubd_release(struct inode * inode, struct file * file);
120 static int ubd_ioctl(struct inode * inode, struct file * file,
121 unsigned int cmd, unsigned long arg);
122
123 #define MAX_DEV (8)
124
125 /* Changed in early boot */
126 static int ubd_do_mmap = 0;
127 #define UBD_MMAP_BLOCK_SIZE PAGE_SIZE
128
129 static struct block_device_operations ubd_blops = {
130 .owner = THIS_MODULE,
131 .open = ubd_open,
132 .release = ubd_release,
133 .ioctl = ubd_ioctl,
134 };
135
136 /* Protected by the queue_lock */
137 static request_queue_t *ubd_queue;
138
139 /* Protected by ubd_lock */
140 static int fake_major = MAJOR_NR;
141
142 static struct gendisk *ubd_gendisk[MAX_DEV];
143 static struct gendisk *fake_gendisk[MAX_DEV];
144
145 #ifdef CONFIG_BLK_DEV_UBD_SYNC
146 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
147 .cl = 1 })
148 #else
149 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
150 .cl = 1 })
151 #endif
152
153 /* Not protected - changed only in ubd_setup_common and then only to
154 * to enable O_SYNC.
155 */
156 static struct openflags global_openflags = OPEN_FLAGS;
157
158 struct cow {
159 /* This is the backing file, actually */
160 char *file;
161 int fd;
162 unsigned long *bitmap;
163 unsigned long bitmap_len;
164 int bitmap_offset;
165 int data_offset;
166 };
167
168 struct ubd {
169 char *file;
170 int count;
171 int fd;
172 __u64 size;
173 struct openflags boot_openflags;
174 struct openflags openflags;
175 int no_cow;
176 struct cow cow;
177 struct platform_device pdev;
178
179 int map_writes;
180 int map_reads;
181 int nomap_writes;
182 int nomap_reads;
183 int write_maps;
184 };
185
186 #define DEFAULT_COW { \
187 .file = NULL, \
188 .fd = -1, \
189 .bitmap = NULL, \
190 .bitmap_offset = 0, \
191 .data_offset = 0, \
192 }
193
194 #define DEFAULT_UBD { \
195 .file = NULL, \
196 .count = 0, \
197 .fd = -1, \
198 .size = -1, \
199 .boot_openflags = OPEN_FLAGS, \
200 .openflags = OPEN_FLAGS, \
201 .no_cow = 0, \
202 .cow = DEFAULT_COW, \
203 .map_writes = 0, \
204 .map_reads = 0, \
205 .nomap_writes = 0, \
206 .nomap_reads = 0, \
207 .write_maps = 0, \
208 }
209
210 struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD };
211
212 static int ubd0_init(void)
213 {
214 struct ubd *dev = &ubd_dev[0];
215
216 if(dev->file == NULL)
217 dev->file = "root_fs";
218 return(0);
219 }
220
221 __initcall(ubd0_init);
222
223 /* Only changed by fake_ide_setup which is a setup */
224 static int fake_ide = 0;
225 static struct proc_dir_entry *proc_ide_root = NULL;
226 static struct proc_dir_entry *proc_ide = NULL;
227
228 static void make_proc_ide(void)
229 {
230 proc_ide_root = proc_mkdir("ide", NULL);
231 proc_ide = proc_mkdir("ide0", proc_ide_root);
232 }
233
234 static int proc_ide_read_media(char *page, char **start, off_t off, int count,
235 int *eof, void *data)
236 {
237 int len;
238
239 strcpy(page, "disk\n");
240 len = strlen("disk\n");
241 len -= off;
242 if (len < count){
243 *eof = 1;
244 if (len <= 0) return 0;
245 }
246 else len = count;
247 *start = page + off;
248 return len;
249 }
250
251 static void make_ide_entries(char *dev_name)
252 {
253 struct proc_dir_entry *dir, *ent;
254 char name[64];
255
256 if(proc_ide_root == NULL) make_proc_ide();
257
258 dir = proc_mkdir(dev_name, proc_ide);
259 if(!dir) return;
260
261 ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir);
262 if(!ent) return;
263 ent->nlink = 1;
264 ent->data = NULL;
265 ent->read_proc = proc_ide_read_media;
266 ent->write_proc = NULL;
267 sprintf(name,"ide0/%s", dev_name);
268 proc_symlink(dev_name, proc_ide_root, name);
269 }
270
271 static int fake_ide_setup(char *str)
272 {
273 fake_ide = 1;
274 return(1);
275 }
276
277 __setup("fake_ide", fake_ide_setup);
278
279 __uml_help(fake_ide_setup,
280 "fake_ide\n"
281 " Create ide0 entries that map onto ubd devices.\n\n"
282 );
283
284 static int parse_unit(char **ptr)
285 {
286 char *str = *ptr, *end;
287 int n = -1;
288
289 if(isdigit(*str)) {
290 n = simple_strtoul(str, &end, 0);
291 if(end == str)
292 return(-1);
293 *ptr = end;
294 }
295 else if (('a' <= *str) && (*str <= 'h')) {
296 n = *str - 'a';
297 str++;
298 *ptr = str;
299 }
300 return(n);
301 }
302
303 static int ubd_setup_common(char *str, int *index_out)
304 {
305 struct ubd *dev;
306 struct openflags flags = global_openflags;
307 char *backing_file;
308 int n, err, i;
309
310 if(index_out) *index_out = -1;
311 n = *str;
312 if(n == '='){
313 char *end;
314 int major;
315
316 str++;
317 if(!strcmp(str, "mmap")){
318 CHOOSE_MODE(printk("mmap not supported by the ubd "
319 "driver in tt mode\n"),
320 ubd_do_mmap = 1);
321 return(0);
322 }
323
324 if(!strcmp(str, "sync")){
325 global_openflags = of_sync(global_openflags);
326 return(0);
327 }
328 major = simple_strtoul(str, &end, 0);
329 if((*end != '\0') || (end == str)){
330 printk(KERN_ERR
331 "ubd_setup : didn't parse major number\n");
332 return(1);
333 }
334
335 err = 1;
336 spin_lock(&ubd_lock);
337 if(fake_major != MAJOR_NR){
338 printk(KERN_ERR "Can't assign a fake major twice\n");
339 goto out1;
340 }
341
342 fake_major = major;
343
344 printk(KERN_INFO "Setting extra ubd major number to %d\n",
345 major);
346 err = 0;
347 out1:
348 spin_unlock(&ubd_lock);
349 return(err);
350 }
351
352 n = parse_unit(&str);
353 if(n < 0){
354 printk(KERN_ERR "ubd_setup : couldn't parse unit number "
355 "'%s'\n", str);
356 return(1);
357 }
358 if(n >= MAX_DEV){
359 printk(KERN_ERR "ubd_setup : index %d out of range "
360 "(%d devices, from 0 to %d)\n", n, MAX_DEV, MAX_DEV - 1);
361 return(1);
362 }
363
364 err = 1;
365 spin_lock(&ubd_lock);
366
367 dev = &ubd_dev[n];
368 if(dev->file != NULL){
369 printk(KERN_ERR "ubd_setup : device already configured\n");
370 goto out;
371 }
372
373 if (index_out)
374 *index_out = n;
375
376 for (i = 0; i < 4; i++) {
377 switch (*str) {
378 case 'r':
379 flags.w = 0;
380 break;
381 case 's':
382 flags.s = 1;
383 break;
384 case 'd':
385 dev->no_cow = 1;
386 break;
387 case '=':
388 str++;
389 goto break_loop;
390 default:
391 printk(KERN_ERR "ubd_setup : Expected '=' or flag letter (r,s or d)\n");
392 goto out;
393 }
394 str++;
395 }
396
397 if (*str == '=')
398 printk(KERN_ERR "ubd_setup : Too many flags specified\n");
399 else
400 printk(KERN_ERR "ubd_setup : Expected '='\n");
401 goto out;
402
403 break_loop:
404 err = 0;
405 backing_file = strchr(str, ',');
406
407 if (!backing_file) {
408 backing_file = strchr(str, ':');
409 }
410
411 if(backing_file){
412 if(dev->no_cow)
413 printk(KERN_ERR "Can't specify both 'd' and a "
414 "cow file\n");
415 else {
416 *backing_file = '\0';
417 backing_file++;
418 }
419 }
420 dev->file = str;
421 dev->cow.file = backing_file;
422 dev->boot_openflags = flags;
423 out:
424 spin_unlock(&ubd_lock);
425 return(err);
426 }
427
428 static int ubd_setup(char *str)
429 {
430 ubd_setup_common(str, NULL);
431 return(1);
432 }
433
434 __setup("ubd", ubd_setup);
435 __uml_help(ubd_setup,
436 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
437 " This is used to associate a device with a file in the underlying\n"
438 " filesystem. When specifying two filenames, the first one is the\n"
439 " COW name and the second is the backing file name. As separator you can\n"
440 " use either a ':' or a ',': the first one allows writing things like;\n"
441 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
442 " while with a ',' the shell would not expand the 2nd '~'.\n"
443 " When using only one filename, UML will detect whether to thread it like\n"
444 " a COW file or a backing file. To override this detection, add the 'd'\n"
445 " flag:\n"
446 " ubd0d=BackingFile\n"
447 " Usually, there is a filesystem in the file, but \n"
448 " that's not required. Swap devices containing swap files can be\n"
449 " specified like this. Also, a file which doesn't contain a\n"
450 " filesystem can have its contents read in the virtual \n"
451 " machine by running 'dd' on the device. <n> must be in the range\n"
452 " 0 to 7. Appending an 'r' to the number will cause that device\n"
453 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
454 " an 's' will cause data to be written to disk on the host immediately.\n\n"
455 );
456
457 static int udb_setup(char *str)
458 {
459 printk("udb%s specified on command line is almost certainly a ubd -> "
460 "udb TYPO\n", str);
461 return(1);
462 }
463
464 __setup("udb", udb_setup);
465 __uml_help(udb_setup,
466 "udb\n"
467 " This option is here solely to catch ubd -> udb typos, which can be\n\n"
468 " to impossible to catch visually unless you specifically look for\n\n"
469 " them. The only result of any option starting with 'udb' is an error\n\n"
470 " in the boot output.\n\n"
471 );
472
473 static int fakehd_set = 0;
474 static int fakehd(char *str)
475 {
476 printk(KERN_INFO "fakehd : Changing ubd name to \"hd\".\n");
477 fakehd_set = 1;
478 return 1;
479 }
480
481 __setup("fakehd", fakehd);
482 __uml_help(fakehd,
483 "fakehd\n"
484 " Change the ubd device name to \"hd\".\n\n"
485 );
486
487 static void do_ubd_request(request_queue_t * q);
488
489 /* Only changed by ubd_init, which is an initcall. */
490 int thread_fd = -1;
491
492 /* Changed by ubd_handler, which is serialized because interrupts only
493 * happen on CPU 0.
494 */
495 int intr_count = 0;
496
497 /* call ubd_finish if you need to serialize */
498 static void __ubd_finish(struct request *req, int error)
499 {
500 int nsect;
501
502 if(error){
503 end_request(req, 0);
504 return;
505 }
506 nsect = req->current_nr_sectors;
507 req->sector += nsect;
508 req->buffer += nsect << 9;
509 req->errors = 0;
510 req->nr_sectors -= nsect;
511 req->current_nr_sectors = 0;
512 end_request(req, 1);
513 }
514
515 static inline void ubd_finish(struct request *req, int error)
516 {
517 spin_lock(&ubd_io_lock);
518 __ubd_finish(req, error);
519 spin_unlock(&ubd_io_lock);
520 }
521
522 /* Called without ubd_io_lock held */
523 static void ubd_handler(void)
524 {
525 struct io_thread_req req;
526 struct request *rq = elv_next_request(ubd_queue);
527 int n, err;
528
529 do_ubd = NULL;
530 intr_count++;
531 n = os_read_file(thread_fd, &req, sizeof(req));
532 if(n != sizeof(req)){
533 printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
534 "err = %d\n", os_getpid(), -n);
535 spin_lock(&ubd_io_lock);
536 end_request(rq, 0);
537 spin_unlock(&ubd_io_lock);
538 return;
539 }
540
541 if((req.op != UBD_MMAP) &&
542 ((req.offset != ((__u64) (rq->sector)) << 9) ||
543 (req.length != (rq->current_nr_sectors) << 9)))
544 panic("I/O op mismatch");
545
546 if(req.map_fd != -1){
547 err = physmem_subst_mapping(req.buffer, req.map_fd,
548 req.map_offset, 1);
549 if(err)
550 printk("ubd_handler - physmem_subst_mapping failed, "
551 "err = %d\n", -err);
552 }
553
554 ubd_finish(rq, req.error);
555 reactivate_fd(thread_fd, UBD_IRQ);
556 do_ubd_request(ubd_queue);
557 }
558
559 static irqreturn_t ubd_intr(int irq, void *dev, struct pt_regs *unused)
560 {
561 ubd_handler();
562 return(IRQ_HANDLED);
563 }
564
565 /* Only changed by ubd_init, which is an initcall. */
566 static int io_pid = -1;
567
568 void kill_io_thread(void)
569 {
570 if(io_pid != -1)
571 os_kill_process(io_pid, 1);
572 }
573
574 __uml_exitcall(kill_io_thread);
575
576 static int ubd_file_size(struct ubd *dev, __u64 *size_out)
577 {
578 char *file;
579
580 file = dev->cow.file ? dev->cow.file : dev->file;
581 return(os_file_size(file, size_out));
582 }
583
584 static void ubd_close(struct ubd *dev)
585 {
586 if(ubd_do_mmap)
587 physmem_forget_descriptor(dev->fd);
588 os_close_file(dev->fd);
589 if(dev->cow.file == NULL)
590 return;
591
592 if(ubd_do_mmap)
593 physmem_forget_descriptor(dev->cow.fd);
594 os_close_file(dev->cow.fd);
595 vfree(dev->cow.bitmap);
596 dev->cow.bitmap = NULL;
597 }
598
599 static int ubd_open_dev(struct ubd *dev)
600 {
601 struct openflags flags;
602 char **back_ptr;
603 int err, create_cow, *create_ptr;
604
605 dev->openflags = dev->boot_openflags;
606 create_cow = 0;
607 create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL;
608 back_ptr = dev->no_cow ? NULL : &dev->cow.file;
609 dev->fd = open_ubd_file(dev->file, &dev->openflags, back_ptr,
610 &dev->cow.bitmap_offset, &dev->cow.bitmap_len,
611 &dev->cow.data_offset, create_ptr);
612
613 if((dev->fd == -ENOENT) && create_cow){
614 dev->fd = create_cow_file(dev->file, dev->cow.file,
615 dev->openflags, 1 << 9, PAGE_SIZE,
616 &dev->cow.bitmap_offset,
617 &dev->cow.bitmap_len,
618 &dev->cow.data_offset);
619 if(dev->fd >= 0){
620 printk(KERN_INFO "Creating \"%s\" as COW file for "
621 "\"%s\"\n", dev->file, dev->cow.file);
622 }
623 }
624
625 if(dev->fd < 0){
626 printk("Failed to open '%s', errno = %d\n", dev->file,
627 -dev->fd);
628 return(dev->fd);
629 }
630
631 if(dev->cow.file != NULL){
632 err = -ENOMEM;
633 dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len);
634 if(dev->cow.bitmap == NULL){
635 printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
636 goto error;
637 }
638 flush_tlb_kernel_vm();
639
640 err = read_cow_bitmap(dev->fd, dev->cow.bitmap,
641 dev->cow.bitmap_offset,
642 dev->cow.bitmap_len);
643 if(err < 0)
644 goto error;
645
646 flags = dev->openflags;
647 flags.w = 0;
648 err = open_ubd_file(dev->cow.file, &flags, NULL, NULL, NULL,
649 NULL, NULL);
650 if(err < 0) goto error;
651 dev->cow.fd = err;
652 }
653 return(0);
654 error:
655 os_close_file(dev->fd);
656 return(err);
657 }
658
659 static int ubd_new_disk(int major, u64 size, int unit,
660 struct gendisk **disk_out)
661
662 {
663 struct gendisk *disk;
664 char from[sizeof("ubd/nnnnn\0")], to[sizeof("discnnnnn/disc\0")];
665 int err;
666
667 disk = alloc_disk(1 << UBD_SHIFT);
668 if(disk == NULL)
669 return(-ENOMEM);
670
671 disk->major = major;
672 disk->first_minor = unit << UBD_SHIFT;
673 disk->fops = &ubd_blops;
674 set_capacity(disk, size / 512);
675 if(major == MAJOR_NR){
676 sprintf(disk->disk_name, "ubd%c", 'a' + unit);
677 sprintf(disk->devfs_name, "ubd/disc%d", unit);
678 sprintf(from, "ubd/%d", unit);
679 sprintf(to, "disc%d/disc", unit);
680 err = devfs_mk_symlink(from, to);
681 if(err)
682 printk("ubd_new_disk failed to make link from %s to "
683 "%s, error = %d\n", from, to, err);
684 }
685 else {
686 sprintf(disk->disk_name, "ubd_fake%d", unit);
687 sprintf(disk->devfs_name, "ubd_fake/disc%d", unit);
688 }
689
690 /* sysfs register (not for ide fake devices) */
691 if (major == MAJOR_NR) {
692 ubd_dev[unit].pdev.id = unit;
693 ubd_dev[unit].pdev.name = DRIVER_NAME;
694 platform_device_register(&ubd_dev[unit].pdev);
695 disk->driverfs_dev = &ubd_dev[unit].pdev.dev;
696 }
697
698 disk->private_data = &ubd_dev[unit];
699 disk->queue = ubd_queue;
700 add_disk(disk);
701
702 *disk_out = disk;
703 return 0;
704 }
705
706 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9))
707
708 static int ubd_add(int n)
709 {
710 struct ubd *dev = &ubd_dev[n];
711 int err;
712
713 if(dev->file == NULL)
714 return(-ENODEV);
715
716 if (ubd_open_dev(dev))
717 return(-ENODEV);
718
719 err = ubd_file_size(dev, &dev->size);
720 if(err < 0)
721 return(err);
722
723 dev->size = ROUND_BLOCK(dev->size);
724
725 err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]);
726 if(err)
727 return(err);
728
729 if(fake_major != MAJOR_NR)
730 ubd_new_disk(fake_major, dev->size, n,
731 &fake_gendisk[n]);
732
733 /* perhaps this should also be under the "if (fake_major)" above */
734 /* using the fake_disk->disk_name and also the fakehd_set name */
735 if (fake_ide)
736 make_ide_entries(ubd_gendisk[n]->disk_name);
737
738 ubd_close(dev);
739 return 0;
740 }
741
742 static int ubd_config(char *str)
743 {
744 int n, err;
745
746 str = uml_strdup(str);
747 if(str == NULL){
748 printk(KERN_ERR "ubd_config failed to strdup string\n");
749 return(1);
750 }
751 err = ubd_setup_common(str, &n);
752 if(err){
753 kfree(str);
754 return(-1);
755 }
756 if(n == -1) return(0);
757
758 spin_lock(&ubd_lock);
759 err = ubd_add(n);
760 if(err)
761 ubd_dev[n].file = NULL;
762 spin_unlock(&ubd_lock);
763
764 return(err);
765 }
766
767 static int ubd_get_config(char *name, char *str, int size, char **error_out)
768 {
769 struct ubd *dev;
770 int n, len = 0;
771
772 n = parse_unit(&name);
773 if((n >= MAX_DEV) || (n < 0)){
774 *error_out = "ubd_get_config : device number out of range";
775 return(-1);
776 }
777
778 dev = &ubd_dev[n];
779 spin_lock(&ubd_lock);
780
781 if(dev->file == NULL){
782 CONFIG_CHUNK(str, size, len, "", 1);
783 goto out;
784 }
785
786 CONFIG_CHUNK(str, size, len, dev->file, 0);
787
788 if(dev->cow.file != NULL){
789 CONFIG_CHUNK(str, size, len, ",", 0);
790 CONFIG_CHUNK(str, size, len, dev->cow.file, 1);
791 }
792 else CONFIG_CHUNK(str, size, len, "", 1);
793
794 out:
795 spin_unlock(&ubd_lock);
796 return(len);
797 }
798
799 static int ubd_remove(char *str)
800 {
801 struct ubd *dev;
802 int n, err = -ENODEV;
803
804 n = parse_unit(&str);
805
806 if((n < 0) || (n >= MAX_DEV))
807 return(err);
808
809 dev = &ubd_dev[n];
810 if(dev->count > 0)
811 return(-EBUSY); /* you cannot remove a open disk */
812
813 err = 0;
814 spin_lock(&ubd_lock);
815
816 if(ubd_gendisk[n] == NULL)
817 goto out;
818
819 del_gendisk(ubd_gendisk[n]);
820 put_disk(ubd_gendisk[n]);
821 ubd_gendisk[n] = NULL;
822
823 if(fake_gendisk[n] != NULL){
824 del_gendisk(fake_gendisk[n]);
825 put_disk(fake_gendisk[n]);
826 fake_gendisk[n] = NULL;
827 }
828
829 platform_device_unregister(&dev->pdev);
830 *dev = ((struct ubd) DEFAULT_UBD);
831 err = 0;
832 out:
833 spin_unlock(&ubd_lock);
834 return(err);
835 }
836
837 static struct mc_device ubd_mc = {
838 .name = "ubd",
839 .config = ubd_config,
840 .get_config = ubd_get_config,
841 .remove = ubd_remove,
842 };
843
844 static int ubd_mc_init(void)
845 {
846 mconsole_register_dev(&ubd_mc);
847 return 0;
848 }
849
850 __initcall(ubd_mc_init);
851
852 static struct device_driver ubd_driver = {
853 .name = DRIVER_NAME,
854 .bus = &platform_bus_type,
855 };
856
857 int ubd_init(void)
858 {
859 int i;
860
861 devfs_mk_dir("ubd");
862 if (register_blkdev(MAJOR_NR, "ubd"))
863 return -1;
864
865 ubd_queue = blk_init_queue(do_ubd_request, &ubd_io_lock);
866 if (!ubd_queue) {
867 unregister_blkdev(MAJOR_NR, "ubd");
868 return -1;
869 }
870
871 if (fake_major != MAJOR_NR) {
872 char name[sizeof("ubd_nnn\0")];
873
874 snprintf(name, sizeof(name), "ubd_%d", fake_major);
875 devfs_mk_dir(name);
876 if (register_blkdev(fake_major, "ubd"))
877 return -1;
878 }
879 driver_register(&ubd_driver);
880 for (i = 0; i < MAX_DEV; i++)
881 ubd_add(i);
882 return 0;
883 }
884
885 late_initcall(ubd_init);
886
887 int ubd_driver_init(void){
888 unsigned long stack;
889 int err;
890
891 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
892 if(global_openflags.s){
893 printk(KERN_INFO "ubd: Synchronous mode\n");
894 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
895 * enough. So use anyway the io thread. */
896 }
897 stack = alloc_stack(0, 0);
898 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
899 &thread_fd);
900 if(io_pid < 0){
901 printk(KERN_ERR
902 "ubd : Failed to start I/O thread (errno = %d) - "
903 "falling back to synchronous I/O\n", -io_pid);
904 io_pid = -1;
905 return(0);
906 }
907 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
908 SA_INTERRUPT, "ubd", ubd_dev);
909 if(err != 0)
910 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
911 return(err);
912 }
913
914 device_initcall(ubd_driver_init);
915
916 static int ubd_open(struct inode *inode, struct file *filp)
917 {
918 struct gendisk *disk = inode->i_bdev->bd_disk;
919 struct ubd *dev = disk->private_data;
920 int err = 0;
921
922 if(dev->count == 0){
923 err = ubd_open_dev(dev);
924 if(err){
925 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
926 disk->disk_name, dev->file, -err);
927 goto out;
928 }
929 }
930 dev->count++;
931 set_disk_ro(disk, !dev->openflags.w);
932
933 /* This should no more be needed. And it didn't work anyway to exclude
934 * read-write remounting of filesystems.*/
935 /*if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){
936 if(--dev->count == 0) ubd_close(dev);
937 err = -EROFS;
938 }*/
939 out:
940 return(err);
941 }
942
943 static int ubd_release(struct inode * inode, struct file * file)
944 {
945 struct gendisk *disk = inode->i_bdev->bd_disk;
946 struct ubd *dev = disk->private_data;
947
948 if(--dev->count == 0)
949 ubd_close(dev);
950 return(0);
951 }
952
953 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
954 __u64 *cow_offset, unsigned long *bitmap,
955 __u64 bitmap_offset, unsigned long *bitmap_words,
956 __u64 bitmap_len)
957 {
958 __u64 sector = io_offset >> 9;
959 int i, update_bitmap = 0;
960
961 for(i = 0; i < length >> 9; i++){
962 if(cow_mask != NULL)
963 ubd_set_bit(i, (unsigned char *) cow_mask);
964 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
965 continue;
966
967 update_bitmap = 1;
968 ubd_set_bit(sector + i, (unsigned char *) bitmap);
969 }
970
971 if(!update_bitmap)
972 return;
973
974 *cow_offset = sector / (sizeof(unsigned long) * 8);
975
976 /* This takes care of the case where we're exactly at the end of the
977 * device, and *cow_offset + 1 is off the end. So, just back it up
978 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
979 * for the original diagnosis.
980 */
981 if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) /
982 sizeof(unsigned long) - 1))
983 (*cow_offset)--;
984
985 bitmap_words[0] = bitmap[*cow_offset];
986 bitmap_words[1] = bitmap[*cow_offset + 1];
987
988 *cow_offset *= sizeof(unsigned long);
989 *cow_offset += bitmap_offset;
990 }
991
992 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
993 __u64 bitmap_offset, __u64 bitmap_len)
994 {
995 __u64 sector = req->offset >> 9;
996 int i;
997
998 if(req->length > (sizeof(req->sector_mask) * 8) << 9)
999 panic("Operation too long");
1000
1001 if(req->op == UBD_READ) {
1002 for(i = 0; i < req->length >> 9; i++){
1003 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1004 ubd_set_bit(i, (unsigned char *)
1005 &req->sector_mask);
1006 }
1007 }
1008 else cowify_bitmap(req->offset, req->length, &req->sector_mask,
1009 &req->cow_offset, bitmap, bitmap_offset,
1010 req->bitmap_words, bitmap_len);
1011 }
1012
1013 static int mmap_fd(struct request *req, struct ubd *dev, __u64 offset)
1014 {
1015 __u64 sector;
1016 unsigned char *bitmap;
1017 int bit, i;
1018
1019 /* mmap must have been requested on the command line */
1020 if(!ubd_do_mmap)
1021 return(-1);
1022
1023 /* The buffer must be page aligned */
1024 if(((unsigned long) req->buffer % UBD_MMAP_BLOCK_SIZE) != 0)
1025 return(-1);
1026
1027 /* The request must be a page long */
1028 if((req->current_nr_sectors << 9) != PAGE_SIZE)
1029 return(-1);
1030
1031 if(dev->cow.file == NULL)
1032 return(dev->fd);
1033
1034 sector = offset >> 9;
1035 bitmap = (unsigned char *) dev->cow.bitmap;
1036 bit = ubd_test_bit(sector, bitmap);
1037
1038 for(i = 1; i < req->current_nr_sectors; i++){
1039 if(ubd_test_bit(sector + i, bitmap) != bit)
1040 return(-1);
1041 }
1042
1043 if(bit || (rq_data_dir(req) == WRITE))
1044 offset += dev->cow.data_offset;
1045
1046 /* The data on disk must be page aligned */
1047 if((offset % UBD_MMAP_BLOCK_SIZE) != 0)
1048 return(-1);
1049
1050 return(bit ? dev->fd : dev->cow.fd);
1051 }
1052
1053 static int prepare_mmap_request(struct ubd *dev, int fd, __u64 offset,
1054 struct request *req,
1055 struct io_thread_req *io_req)
1056 {
1057 int err;
1058
1059 if(rq_data_dir(req) == WRITE){
1060 /* Writes are almost no-ops since the new data is already in the
1061 * host page cache
1062 */
1063 dev->map_writes++;
1064 if(dev->cow.file != NULL)
1065 cowify_bitmap(io_req->offset, io_req->length,
1066 &io_req->sector_mask, &io_req->cow_offset,
1067 dev->cow.bitmap, dev->cow.bitmap_offset,
1068 io_req->bitmap_words,
1069 dev->cow.bitmap_len);
1070 }
1071 else {
1072 int w;
1073
1074 if((dev->cow.file != NULL) && (fd == dev->cow.fd))
1075 w = 0;
1076 else w = dev->openflags.w;
1077
1078 if((dev->cow.file != NULL) && (fd == dev->fd))
1079 offset += dev->cow.data_offset;
1080
1081 err = physmem_subst_mapping(req->buffer, fd, offset, w);
1082 if(err){
1083 printk("physmem_subst_mapping failed, err = %d\n",
1084 -err);
1085 return(1);
1086 }
1087 dev->map_reads++;
1088 }
1089 io_req->op = UBD_MMAP;
1090 io_req->buffer = req->buffer;
1091 return(0);
1092 }
1093
1094 /* Called with ubd_io_lock held */
1095 static int prepare_request(struct request *req, struct io_thread_req *io_req)
1096 {
1097 struct gendisk *disk = req->rq_disk;
1098 struct ubd *dev = disk->private_data;
1099 __u64 offset;
1100 int len, fd;
1101
1102 if(req->rq_status == RQ_INACTIVE) return(1);
1103
1104 /* This should be impossible now */
1105 if((rq_data_dir(req) == WRITE) && !dev->openflags.w){
1106 printk("Write attempted on readonly ubd device %s\n",
1107 disk->disk_name);
1108 end_request(req, 0);
1109 return(1);
1110 }
1111
1112 offset = ((__u64) req->sector) << 9;
1113 len = req->current_nr_sectors << 9;
1114
1115 io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd;
1116 io_req->fds[1] = dev->fd;
1117 io_req->map_fd = -1;
1118 io_req->cow_offset = -1;
1119 io_req->offset = offset;
1120 io_req->length = len;
1121 io_req->error = 0;
1122 io_req->sector_mask = 0;
1123
1124 fd = mmap_fd(req, dev, io_req->offset);
1125 if(fd > 0){
1126 /* If mmapping is otherwise OK, but the first access to the
1127 * page is a write, then it's not mapped in yet. So we have
1128 * to write the data to disk first, then we can map the disk
1129 * page in and continue normally from there.
1130 */
1131 if((rq_data_dir(req) == WRITE) && !is_remapped(req->buffer)){
1132 io_req->map_fd = dev->fd;
1133 io_req->map_offset = io_req->offset +
1134 dev->cow.data_offset;
1135 dev->write_maps++;
1136 }
1137 else return(prepare_mmap_request(dev, fd, io_req->offset, req,
1138 io_req));
1139 }
1140
1141 if(rq_data_dir(req) == READ)
1142 dev->nomap_reads++;
1143 else dev->nomap_writes++;
1144
1145 io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE;
1146 io_req->offsets[0] = 0;
1147 io_req->offsets[1] = dev->cow.data_offset;
1148 io_req->buffer = req->buffer;
1149 io_req->sectorsize = 1 << 9;
1150
1151 if(dev->cow.file != NULL)
1152 cowify_req(io_req, dev->cow.bitmap, dev->cow.bitmap_offset,
1153 dev->cow.bitmap_len);
1154
1155 return(0);
1156 }
1157
1158 /* Called with ubd_io_lock held */
1159 static void do_ubd_request(request_queue_t *q)
1160 {
1161 struct io_thread_req io_req;
1162 struct request *req;
1163 int err, n;
1164
1165 if(thread_fd == -1){
1166 while((req = elv_next_request(q)) != NULL){
1167 err = prepare_request(req, &io_req);
1168 if(!err){
1169 do_io(&io_req);
1170 __ubd_finish(req, io_req.error);
1171 }
1172 }
1173 }
1174 else {
1175 if(do_ubd || (req = elv_next_request(q)) == NULL)
1176 return;
1177 err = prepare_request(req, &io_req);
1178 if(!err){
1179 do_ubd = ubd_handler;
1180 n = os_write_file(thread_fd, (char *) &io_req,
1181 sizeof(io_req));
1182 if(n != sizeof(io_req))
1183 printk("write to io thread failed, "
1184 "errno = %d\n", -n);
1185 }
1186 }
1187 }
1188
1189 static int ubd_ioctl(struct inode * inode, struct file * file,
1190 unsigned int cmd, unsigned long arg)
1191 {
1192 struct hd_geometry __user *loc = (struct hd_geometry __user *) arg;
1193 struct ubd *dev = inode->i_bdev->bd_disk->private_data;
1194 struct hd_driveid ubd_id = {
1195 .cyls = 0,
1196 .heads = 128,
1197 .sectors = 32,
1198 };
1199
1200 switch (cmd) {
1201 struct hd_geometry g;
1202 struct cdrom_volctrl volume;
1203 case HDIO_GETGEO:
1204 if(!loc) return(-EINVAL);
1205 g.heads = 128;
1206 g.sectors = 32;
1207 g.cylinders = dev->size / (128 * 32 * 512);
1208 g.start = get_start_sect(inode->i_bdev);
1209 return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0);
1210
1211 case HDIO_GET_IDENTITY:
1212 ubd_id.cyls = dev->size / (128 * 32 * 512);
1213 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1214 sizeof(ubd_id)))
1215 return(-EFAULT);
1216 return(0);
1217
1218 case CDROMVOLREAD:
1219 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1220 return(-EFAULT);
1221 volume.channel0 = 255;
1222 volume.channel1 = 255;
1223 volume.channel2 = 255;
1224 volume.channel3 = 255;
1225 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1226 return(-EFAULT);
1227 return(0);
1228 }
1229 return(-EINVAL);
1230 }
1231
1232 static int ubd_check_remapped(int fd, unsigned long address, int is_write,
1233 __u64 offset)
1234 {
1235 __u64 bitmap_offset;
1236 unsigned long new_bitmap[2];
1237 int i, err, n;
1238
1239 /* If it's not a write access, we can't do anything about it */
1240 if(!is_write)
1241 return(0);
1242
1243 /* We have a write */
1244 for(i = 0; i < sizeof(ubd_dev) / sizeof(ubd_dev[0]); i++){
1245 struct ubd *dev = &ubd_dev[i];
1246
1247 if((dev->fd != fd) && (dev->cow.fd != fd))
1248 continue;
1249
1250 /* It's a write to a ubd device */
1251
1252 /* This should be impossible now */
1253 if(!dev->openflags.w){
1254 /* It's a write access on a read-only device - probably
1255 * shouldn't happen. If the kernel is trying to change
1256 * something with no intention of writing it back out,
1257 * then this message will clue us in that this needs
1258 * fixing
1259 */
1260 printk("Write access to mapped page from readonly ubd "
1261 "device %d\n", i);
1262 return(0);
1263 }
1264
1265 /* It's a write to a writeable ubd device - it must be COWed
1266 * because, otherwise, the page would have been mapped in
1267 * writeable
1268 */
1269
1270 if(!dev->cow.file)
1271 panic("Write fault on writeable non-COW ubd device %d",
1272 i);
1273
1274 /* It should also be an access to the backing file since the
1275 * COW pages should be mapped in read-write
1276 */
1277
1278 if(fd == dev->fd)
1279 panic("Write fault on a backing page of ubd "
1280 "device %d\n", i);
1281
1282 /* So, we do the write, copying the backing data to the COW
1283 * file...
1284 */
1285
1286 err = os_seek_file(dev->fd, offset + dev->cow.data_offset);
1287 if(err < 0)
1288 panic("Couldn't seek to %lld in COW file of ubd "
1289 "device %d, err = %d",
1290 offset + dev->cow.data_offset, i, -err);
1291
1292 n = os_write_file(dev->fd, (void *) address, PAGE_SIZE);
1293 if(n != PAGE_SIZE)
1294 panic("Couldn't copy data to COW file of ubd "
1295 "device %d, err = %d", i, -n);
1296
1297 /* ... updating the COW bitmap... */
1298
1299 cowify_bitmap(offset, PAGE_SIZE, NULL, &bitmap_offset,
1300 dev->cow.bitmap, dev->cow.bitmap_offset,
1301 new_bitmap, dev->cow.bitmap_len);
1302
1303 err = os_seek_file(dev->fd, bitmap_offset);
1304 if(err < 0)
1305 panic("Couldn't seek to %lld in COW file of ubd "
1306 "device %d, err = %d", bitmap_offset, i, -err);
1307
1308 n = os_write_file(dev->fd, new_bitmap, sizeof(new_bitmap));
1309 if(n != sizeof(new_bitmap))
1310 panic("Couldn't update bitmap of ubd device %d, "
1311 "err = %d", i, -n);
1312
1313 /* Maybe we can map the COW page in, and maybe we can't. If
1314 * it is a pre-V3 COW file, we can't, since the alignment will
1315 * be wrong. If it is a V3 or later COW file which has been
1316 * moved to a system with a larger page size, then maybe we
1317 * can't, depending on the exact location of the page.
1318 */
1319
1320 offset += dev->cow.data_offset;
1321
1322 /* Remove the remapping, putting the original anonymous page
1323 * back. If the COW file can be mapped in, that is done.
1324 * Otherwise, the COW page is read in.
1325 */
1326
1327 if(!physmem_remove_mapping((void *) address))
1328 panic("Address 0x%lx not remapped by ubd device %d",
1329 address, i);
1330 if((offset % UBD_MMAP_BLOCK_SIZE) == 0)
1331 physmem_subst_mapping((void *) address, dev->fd,
1332 offset, 1);
1333 else {
1334 err = os_seek_file(dev->fd, offset);
1335 if(err < 0)
1336 panic("Couldn't seek to %lld in COW file of "
1337 "ubd device %d, err = %d", offset, i,
1338 -err);
1339
1340 n = os_read_file(dev->fd, (void *) address, PAGE_SIZE);
1341 if(n != PAGE_SIZE)
1342 panic("Failed to read page from offset %llx of "
1343 "COW file of ubd device %d, err = %d",
1344 offset, i, -n);
1345 }
1346
1347 return(1);
1348 }
1349
1350 /* It's not a write on a ubd device */
1351 return(0);
1352 }
1353
1354 static struct remapper ubd_remapper = {
1355 .list = LIST_HEAD_INIT(ubd_remapper.list),
1356 .proc = ubd_check_remapped,
1357 };
1358
1359 static int ubd_remapper_setup(void)
1360 {
1361 if(ubd_do_mmap)
1362 register_remapper(&ubd_remapper);
1363
1364 return(0);
1365 }
1366
1367 __initcall(ubd_remapper_setup);
1368
1369 static int same_backing_files(char *from_cmdline, char *from_cow, char *cow)
1370 {
1371 struct uml_stat buf1, buf2;
1372 int err;
1373
1374 if(from_cmdline == NULL) return(1);
1375 if(!strcmp(from_cmdline, from_cow)) return(1);
1376
1377 err = os_stat_file(from_cmdline, &buf1);
1378 if(err < 0){
1379 printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err);
1380 return(1);
1381 }
1382 err = os_stat_file(from_cow, &buf2);
1383 if(err < 0){
1384 printk("Couldn't stat '%s', err = %d\n", from_cow, -err);
1385 return(1);
1386 }
1387 if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
1388 return(1);
1389
1390 printk("Backing file mismatch - \"%s\" requested,\n"
1391 "\"%s\" specified in COW header of \"%s\"\n",
1392 from_cmdline, from_cow, cow);
1393 return(0);
1394 }
1395
1396 static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
1397 {
1398 unsigned long modtime;
1399 long long actual;
1400 int err;
1401
1402 err = os_file_modtime(file, &modtime);
1403 if(err < 0){
1404 printk("Failed to get modification time of backing file "
1405 "\"%s\", err = %d\n", file, -err);
1406 return(err);
1407 }
1408
1409 err = os_file_size(file, &actual);
1410 if(err < 0){
1411 printk("Failed to get size of backing file \"%s\", "
1412 "err = %d\n", file, -err);
1413 return(err);
1414 }
1415
1416 if(actual != size){
1417 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
1418 * the typecast.*/
1419 printk("Size mismatch (%llu vs %llu) of COW header vs backing "
1420 "file\n", (unsigned long long) size, actual);
1421 return(-EINVAL);
1422 }
1423 if(modtime != mtime){
1424 printk("mtime mismatch (%ld vs %ld) of COW header vs backing "
1425 "file\n", mtime, modtime);
1426 return(-EINVAL);
1427 }
1428 return(0);
1429 }
1430
1431 int read_cow_bitmap(int fd, void *buf, int offset, int len)
1432 {
1433 int err;
1434
1435 err = os_seek_file(fd, offset);
1436 if(err < 0)
1437 return(err);
1438
1439 err = os_read_file(fd, buf, len);
1440 if(err < 0)
1441 return(err);
1442
1443 return(0);
1444 }
1445
1446 int open_ubd_file(char *file, struct openflags *openflags,
1447 char **backing_file_out, int *bitmap_offset_out,
1448 unsigned long *bitmap_len_out, int *data_offset_out,
1449 int *create_cow_out)
1450 {
1451 time_t mtime;
1452 unsigned long long size;
1453 __u32 version, align;
1454 char *backing_file;
1455 int fd, err, sectorsize, same, mode = 0644;
1456
1457 fd = os_open_file(file, *openflags, mode);
1458 if(fd < 0){
1459 if((fd == -ENOENT) && (create_cow_out != NULL))
1460 *create_cow_out = 1;
1461 if(!openflags->w ||
1462 ((fd != -EROFS) && (fd != -EACCES))) return(fd);
1463 openflags->w = 0;
1464 fd = os_open_file(file, *openflags, mode);
1465 if(fd < 0)
1466 return(fd);
1467 }
1468
1469 err = os_lock_file(fd, openflags->w);
1470 if(err < 0){
1471 printk("Failed to lock '%s', err = %d\n", file, -err);
1472 goto out_close;
1473 }
1474
1475 if(backing_file_out == NULL) return(fd);
1476
1477 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
1478 &size, &sectorsize, &align, bitmap_offset_out);
1479 if(err && (*backing_file_out != NULL)){
1480 printk("Failed to read COW header from COW file \"%s\", "
1481 "errno = %d\n", file, -err);
1482 goto out_close;
1483 }
1484 if(err) return(fd);
1485
1486 if(backing_file_out == NULL) return(fd);
1487
1488 same = same_backing_files(*backing_file_out, backing_file, file);
1489
1490 if(!same && !backing_file_mismatch(*backing_file_out, size, mtime)){
1491 printk("Switching backing file to '%s'\n", *backing_file_out);
1492 err = write_cow_header(file, fd, *backing_file_out,
1493 sectorsize, align, &size);
1494 if(err){
1495 printk("Switch failed, errno = %d\n", -err);
1496 return(err);
1497 }
1498 }
1499 else {
1500 *backing_file_out = backing_file;
1501 err = backing_file_mismatch(*backing_file_out, size, mtime);
1502 if(err) goto out_close;
1503 }
1504
1505 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
1506 bitmap_len_out, data_offset_out);
1507
1508 return(fd);
1509 out_close:
1510 os_close_file(fd);
1511 return(err);
1512 }
1513
1514 int create_cow_file(char *cow_file, char *backing_file, struct openflags flags,
1515 int sectorsize, int alignment, int *bitmap_offset_out,
1516 unsigned long *bitmap_len_out, int *data_offset_out)
1517 {
1518 int err, fd;
1519
1520 flags.c = 1;
1521 fd = open_ubd_file(cow_file, &flags, NULL, NULL, NULL, NULL, NULL);
1522 if(fd < 0){
1523 err = fd;
1524 printk("Open of COW file '%s' failed, errno = %d\n", cow_file,
1525 -err);
1526 goto out;
1527 }
1528
1529 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
1530 bitmap_offset_out, bitmap_len_out,
1531 data_offset_out);
1532 if(!err)
1533 return(fd);
1534 os_close_file(fd);
1535 out:
1536 return(err);
1537 }
1538
1539 static int update_bitmap(struct io_thread_req *req)
1540 {
1541 int n;
1542
1543 if(req->cow_offset == -1)
1544 return(0);
1545
1546 n = os_seek_file(req->fds[1], req->cow_offset);
1547 if(n < 0){
1548 printk("do_io - bitmap lseek failed : err = %d\n", -n);
1549 return(1);
1550 }
1551
1552 n = os_write_file(req->fds[1], &req->bitmap_words,
1553 sizeof(req->bitmap_words));
1554 if(n != sizeof(req->bitmap_words)){
1555 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n,
1556 req->fds[1]);
1557 return(1);
1558 }
1559
1560 return(0);
1561 }
1562
1563 void do_io(struct io_thread_req *req)
1564 {
1565 char *buf;
1566 unsigned long len;
1567 int n, nsectors, start, end, bit;
1568 int err;
1569 __u64 off;
1570
1571 if(req->op == UBD_MMAP){
1572 /* Touch the page to force the host to do any necessary IO to
1573 * get it into memory
1574 */
1575 n = *((volatile int *) req->buffer);
1576 req->error = update_bitmap(req);
1577 return;
1578 }
1579
1580 nsectors = req->length / req->sectorsize;
1581 start = 0;
1582 do {
1583 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask);
1584 end = start;
1585 while((end < nsectors) &&
1586 (ubd_test_bit(end, (unsigned char *)
1587 &req->sector_mask) == bit))
1588 end++;
1589
1590 off = req->offset + req->offsets[bit] +
1591 start * req->sectorsize;
1592 len = (end - start) * req->sectorsize;
1593 buf = &req->buffer[start * req->sectorsize];
1594
1595 err = os_seek_file(req->fds[bit], off);
1596 if(err < 0){
1597 printk("do_io - lseek failed : err = %d\n", -err);
1598 req->error = 1;
1599 return;
1600 }
1601 if(req->op == UBD_READ){
1602 n = 0;
1603 do {
1604 buf = &buf[n];
1605 len -= n;
1606 n = os_read_file(req->fds[bit], buf, len);
1607 if (n < 0) {
1608 printk("do_io - read failed, err = %d "
1609 "fd = %d\n", -n, req->fds[bit]);
1610 req->error = 1;
1611 return;
1612 }
1613 } while((n < len) && (n != 0));
1614 if (n < len) memset(&buf[n], 0, len - n);
1615 } else {
1616 n = os_write_file(req->fds[bit], buf, len);
1617 if(n != len){
1618 printk("do_io - write failed err = %d "
1619 "fd = %d\n", -n, req->fds[bit]);
1620 req->error = 1;
1621 return;
1622 }
1623 }
1624
1625 start = end;
1626 } while(start < nsectors);
1627
1628 req->error = update_bitmap(req);
1629 }
1630
1631 /* Changed in start_io_thread, which is serialized by being called only
1632 * from ubd_init, which is an initcall.
1633 */
1634 int kernel_fd = -1;
1635
1636 /* Only changed by the io thread */
1637 int io_count = 0;
1638
1639 int io_thread(void *arg)
1640 {
1641 struct io_thread_req req;
1642 int n;
1643
1644 ignore_sigwinch_sig();
1645 while(1){
1646 n = os_read_file(kernel_fd, &req, sizeof(req));
1647 if(n != sizeof(req)){
1648 if(n < 0)
1649 printk("io_thread - read failed, fd = %d, "
1650 "err = %d\n", kernel_fd, -n);
1651 else {
1652 printk("io_thread - short read, fd = %d, "
1653 "length = %d\n", kernel_fd, n);
1654 }
1655 continue;
1656 }
1657 io_count++;
1658 do_io(&req);
1659 n = os_write_file(kernel_fd, &req, sizeof(req));
1660 if(n != sizeof(req))
1661 printk("io_thread - write failed, fd = %d, err = %d\n",
1662 kernel_fd, -n);
1663 }
1664 }
1665
1666 /*
1667 * Overrides for Emacs so that we follow Linus's tabbing style.
1668 * Emacs will notice this stuff at the end of the file and automatically
1669 * adjust the settings for this buffer only. This must remain at the end
1670 * of the file.
1671 * ---------------------------------------------------------------------------
1672 * Local variables:
1673 * c-file-style: "linux"
1674 * End:
1675 */
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