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 UBD_SHIFT 4
21
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/ata.h>
26 #include <linux/hdreg.h>
27 #include <linux/cdrom.h>
28 #include <linux/proc_fs.h>
29 #include <linux/seq_file.h>
30 #include <linux/ctype.h>
31 #include <linux/slab.h>
32 #include <linux/vmalloc.h>
33 #include <linux/platform_device.h>
34 #include <linux/scatterlist.h>
35 #include <asm/tlbflush.h>
36 #include <kern_util.h>
37 #include "mconsole_kern.h"
38 #include <init.h>
39 #include <irq_kern.h>
40 #include "ubd.h"
41 #include <os.h>
42 #include "cow.h"
43
44 enum ubd_req { UBD_READ, UBD_WRITE };
45
46 struct io_thread_req {
47 struct request *req;
48 enum ubd_req op;
49 int fds[2];
50 unsigned long offsets[2];
51 unsigned long long offset;
52 unsigned long length;
53 char *buffer;
54 int sectorsize;
55 unsigned long sector_mask;
56 unsigned long long cow_offset;
57 unsigned long bitmap_words[2];
58 int error;
59 };
60
ubd_test_bit(__u64 bit,unsigned char * data)61 static inline int ubd_test_bit(__u64 bit, unsigned char *data)
62 {
63 __u64 n;
64 int bits, off;
65
66 bits = sizeof(data[0]) * 8;
67 n = bit / bits;
68 off = bit % bits;
69 return (data[n] & (1 << off)) != 0;
70 }
71
ubd_set_bit(__u64 bit,unsigned char * data)72 static inline void ubd_set_bit(__u64 bit, unsigned char *data)
73 {
74 __u64 n;
75 int bits, off;
76
77 bits = sizeof(data[0]) * 8;
78 n = bit / bits;
79 off = bit % bits;
80 data[n] |= (1 << off);
81 }
82 /*End stuff from ubd_user.h*/
83
84 #define DRIVER_NAME "uml-blkdev"
85
86 static DEFINE_MUTEX(ubd_lock);
87 static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
88
89 static int ubd_open(struct block_device *bdev, fmode_t mode);
90 static void ubd_release(struct gendisk *disk, fmode_t mode);
91 static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
92 unsigned int cmd, unsigned long arg);
93 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);
94
95 #define MAX_DEV (16)
96
97 static const struct block_device_operations ubd_blops = {
98 .owner = THIS_MODULE,
99 .open = ubd_open,
100 .release = ubd_release,
101 .ioctl = ubd_ioctl,
102 .getgeo = ubd_getgeo,
103 };
104
105 /* Protected by ubd_lock */
106 static int fake_major = UBD_MAJOR;
107 static struct gendisk *ubd_gendisk[MAX_DEV];
108 static struct gendisk *fake_gendisk[MAX_DEV];
109
110 #ifdef CONFIG_BLK_DEV_UBD_SYNC
111 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
112 .cl = 1 })
113 #else
114 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
115 .cl = 1 })
116 #endif
117 static struct openflags global_openflags = OPEN_FLAGS;
118
119 struct cow {
120 /* backing file name */
121 char *file;
122 /* backing file fd */
123 int fd;
124 unsigned long *bitmap;
125 unsigned long bitmap_len;
126 int bitmap_offset;
127 int data_offset;
128 };
129
130 #define MAX_SG 64
131
132 struct ubd {
133 struct list_head restart;
134 /* name (and fd, below) of the file opened for writing, either the
135 * backing or the cow file. */
136 char *file;
137 int count;
138 int fd;
139 __u64 size;
140 struct openflags boot_openflags;
141 struct openflags openflags;
142 unsigned shared:1;
143 unsigned no_cow:1;
144 struct cow cow;
145 struct platform_device pdev;
146 struct request_queue *queue;
147 spinlock_t lock;
148 struct scatterlist sg[MAX_SG];
149 struct request *request;
150 int start_sg, end_sg;
151 sector_t rq_pos;
152 };
153
154 #define DEFAULT_COW { \
155 .file = NULL, \
156 .fd = -1, \
157 .bitmap = NULL, \
158 .bitmap_offset = 0, \
159 .data_offset = 0, \
160 }
161
162 #define DEFAULT_UBD { \
163 .file = NULL, \
164 .count = 0, \
165 .fd = -1, \
166 .size = -1, \
167 .boot_openflags = OPEN_FLAGS, \
168 .openflags = OPEN_FLAGS, \
169 .no_cow = 0, \
170 .shared = 0, \
171 .cow = DEFAULT_COW, \
172 .lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
173 .request = NULL, \
174 .start_sg = 0, \
175 .end_sg = 0, \
176 .rq_pos = 0, \
177 }
178
179 /* Protected by ubd_lock */
180 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
181
182 /* Only changed by fake_ide_setup which is a setup */
183 static int fake_ide = 0;
184 static struct proc_dir_entry *proc_ide_root = NULL;
185 static struct proc_dir_entry *proc_ide = NULL;
186
make_proc_ide(void)187 static void make_proc_ide(void)
188 {
189 proc_ide_root = proc_mkdir("ide", NULL);
190 proc_ide = proc_mkdir("ide0", proc_ide_root);
191 }
192
fake_ide_media_proc_show(struct seq_file * m,void * v)193 static int fake_ide_media_proc_show(struct seq_file *m, void *v)
194 {
195 seq_puts(m, "disk\n");
196 return 0;
197 }
198
fake_ide_media_proc_open(struct inode * inode,struct file * file)199 static int fake_ide_media_proc_open(struct inode *inode, struct file *file)
200 {
201 return single_open(file, fake_ide_media_proc_show, NULL);
202 }
203
204 static const struct file_operations fake_ide_media_proc_fops = {
205 .owner = THIS_MODULE,
206 .open = fake_ide_media_proc_open,
207 .read = seq_read,
208 .llseek = seq_lseek,
209 .release = single_release,
210 };
211
make_ide_entries(const char * dev_name)212 static void make_ide_entries(const char *dev_name)
213 {
214 struct proc_dir_entry *dir, *ent;
215 char name[64];
216
217 if(proc_ide_root == NULL) make_proc_ide();
218
219 dir = proc_mkdir(dev_name, proc_ide);
220 if(!dir) return;
221
222 ent = proc_create("media", S_IRUGO, dir, &fake_ide_media_proc_fops);
223 if(!ent) return;
224 snprintf(name, sizeof(name), "ide0/%s", dev_name);
225 proc_symlink(dev_name, proc_ide_root, name);
226 }
227
fake_ide_setup(char * str)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
parse_unit(char ** ptr)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 */
ubd_setup_common(char * str,int * index_out,char ** error_out)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 goto out1;
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 goto out1;
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("rscd="); 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 '=':
344 str++;
345 goto break_loop;
346 default:
347 *error_out = "Expected '=' or flag letter "
348 "(r, s, c, or d)";
349 goto out;
350 }
351 str++;
352 }
353
354 if (*str == '=')
355 *error_out = "Too many flags specified";
356 else
357 *error_out = "Missing '='";
358 goto out;
359
360 break_loop:
361 backing_file = strchr(str, ',');
362
363 if (backing_file == NULL)
364 backing_file = strchr(str, ':');
365
366 if(backing_file != NULL){
367 if(ubd_dev->no_cow){
368 *error_out = "Can't specify both 'd' and a cow file";
369 goto out;
370 }
371 else {
372 *backing_file = '\0';
373 backing_file++;
374 }
375 }
376 err = 0;
377 ubd_dev->file = str;
378 ubd_dev->cow.file = backing_file;
379 ubd_dev->boot_openflags = flags;
380 out:
381 mutex_unlock(&ubd_lock);
382 return err;
383 }
384
ubd_setup(char * str)385 static int ubd_setup(char *str)
386 {
387 char *error;
388 int err;
389
390 err = ubd_setup_common(str, NULL, &error);
391 if(err)
392 printk(KERN_ERR "Failed to initialize device with \"%s\" : "
393 "%s\n", str, error);
394 return 1;
395 }
396
397 __setup("ubd", ubd_setup);
398 __uml_help(ubd_setup,
399 "ubd<n><flags>=<filename>[(:|,)<filename2>]\n"
400 " This is used to associate a device with a file in the underlying\n"
401 " filesystem. When specifying two filenames, the first one is the\n"
402 " COW name and the second is the backing file name. As separator you can\n"
403 " use either a ':' or a ',': the first one allows writing things like;\n"
404 " ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n"
405 " while with a ',' the shell would not expand the 2nd '~'.\n"
406 " When using only one filename, UML will detect whether to treat it like\n"
407 " a COW file or a backing file. To override this detection, add the 'd'\n"
408 " flag:\n"
409 " ubd0d=BackingFile\n"
410 " Usually, there is a filesystem in the file, but \n"
411 " that's not required. Swap devices containing swap files can be\n"
412 " specified like this. Also, a file which doesn't contain a\n"
413 " filesystem can have its contents read in the virtual \n"
414 " machine by running 'dd' on the device. <n> must be in the range\n"
415 " 0 to 7. Appending an 'r' to the number will cause that device\n"
416 " to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
417 " an 's' will cause data to be written to disk on the host immediately.\n"
418 " 'c' will cause the device to be treated as being shared between multiple\n"
419 " UMLs and file locking will be turned off - this is appropriate for a\n"
420 " cluster filesystem and inappropriate at almost all other times.\n\n"
421 );
422
udb_setup(char * str)423 static int udb_setup(char *str)
424 {
425 printk("udb%s specified on command line is almost certainly a ubd -> "
426 "udb TYPO\n", str);
427 return 1;
428 }
429
430 __setup("udb", udb_setup);
431 __uml_help(udb_setup,
432 "udb\n"
433 " This option is here solely to catch ubd -> udb typos, which can be\n"
434 " to impossible to catch visually unless you specifically look for\n"
435 " them. The only result of any option starting with 'udb' is an error\n"
436 " in the boot output.\n\n"
437 );
438
439 static void do_ubd_request(struct request_queue * q);
440
441 /* Only changed by ubd_init, which is an initcall. */
442 static int thread_fd = -1;
443 static LIST_HEAD(restart);
444
445 /* XXX - move this inside ubd_intr. */
446 /* Called without dev->lock held, and only in interrupt context. */
ubd_handler(void)447 static void ubd_handler(void)
448 {
449 struct io_thread_req *req;
450 struct ubd *ubd;
451 struct list_head *list, *next_ele;
452 unsigned long flags;
453 int n;
454
455 while(1){
456 n = os_read_file(thread_fd, &req,
457 sizeof(struct io_thread_req *));
458 if(n != sizeof(req)){
459 if(n == -EAGAIN)
460 break;
461 printk(KERN_ERR "spurious interrupt in ubd_handler, "
462 "err = %d\n", -n);
463 return;
464 }
465
466 blk_end_request(req->req, 0, req->length);
467 kfree(req);
468 }
469 reactivate_fd(thread_fd, UBD_IRQ);
470
471 list_for_each_safe(list, next_ele, &restart){
472 ubd = container_of(list, struct ubd, restart);
473 list_del_init(&ubd->restart);
474 spin_lock_irqsave(&ubd->lock, flags);
475 do_ubd_request(ubd->queue);
476 spin_unlock_irqrestore(&ubd->lock, flags);
477 }
478 }
479
ubd_intr(int irq,void * dev)480 static irqreturn_t ubd_intr(int irq, void *dev)
481 {
482 ubd_handler();
483 return IRQ_HANDLED;
484 }
485
486 /* Only changed by ubd_init, which is an initcall. */
487 static int io_pid = -1;
488
kill_io_thread(void)489 static void kill_io_thread(void)
490 {
491 if(io_pid != -1)
492 os_kill_process(io_pid, 1);
493 }
494
495 __uml_exitcall(kill_io_thread);
496
ubd_file_size(struct ubd * ubd_dev,__u64 * size_out)497 static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
498 {
499 char *file;
500 int fd;
501 int err;
502
503 __u32 version;
504 __u32 align;
505 char *backing_file;
506 time_t mtime;
507 unsigned long long size;
508 int sector_size;
509 int bitmap_offset;
510
511 if (ubd_dev->file && ubd_dev->cow.file) {
512 file = ubd_dev->cow.file;
513
514 goto out;
515 }
516
517 fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0);
518 if (fd < 0)
519 return fd;
520
521 err = read_cow_header(file_reader, &fd, &version, &backing_file, \
522 &mtime, &size, §or_size, &align, &bitmap_offset);
523 os_close_file(fd);
524
525 if(err == -EINVAL)
526 file = ubd_dev->file;
527 else
528 file = backing_file;
529
530 out:
531 return os_file_size(file, size_out);
532 }
533
read_cow_bitmap(int fd,void * buf,int offset,int len)534 static int read_cow_bitmap(int fd, void *buf, int offset, int len)
535 {
536 int err;
537
538 err = os_seek_file(fd, offset);
539 if (err < 0)
540 return err;
541
542 err = os_read_file(fd, buf, len);
543 if (err < 0)
544 return err;
545
546 return 0;
547 }
548
backing_file_mismatch(char * file,__u64 size,time_t mtime)549 static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
550 {
551 unsigned long modtime;
552 unsigned long long actual;
553 int err;
554
555 err = os_file_modtime(file, &modtime);
556 if (err < 0) {
557 printk(KERN_ERR "Failed to get modification time of backing "
558 "file \"%s\", err = %d\n", file, -err);
559 return err;
560 }
561
562 err = os_file_size(file, &actual);
563 if (err < 0) {
564 printk(KERN_ERR "Failed to get size of backing file \"%s\", "
565 "err = %d\n", file, -err);
566 return err;
567 }
568
569 if (actual != size) {
570 /*__u64 can be a long on AMD64 and with %lu GCC complains; so
571 * the typecast.*/
572 printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header "
573 "vs backing file\n", (unsigned long long) size, actual);
574 return -EINVAL;
575 }
576 if (modtime != mtime) {
577 printk(KERN_ERR "mtime mismatch (%ld vs %ld) of COW header vs "
578 "backing file\n", mtime, modtime);
579 return -EINVAL;
580 }
581 return 0;
582 }
583
path_requires_switch(char * from_cmdline,char * from_cow,char * cow)584 static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
585 {
586 struct uml_stat buf1, buf2;
587 int err;
588
589 if (from_cmdline == NULL)
590 return 0;
591 if (!strcmp(from_cmdline, from_cow))
592 return 0;
593
594 err = os_stat_file(from_cmdline, &buf1);
595 if (err < 0) {
596 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline,
597 -err);
598 return 0;
599 }
600 err = os_stat_file(from_cow, &buf2);
601 if (err < 0) {
602 printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow,
603 -err);
604 return 1;
605 }
606 if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
607 return 0;
608
609 printk(KERN_ERR "Backing file mismatch - \"%s\" requested, "
610 "\"%s\" specified in COW header of \"%s\"\n",
611 from_cmdline, from_cow, cow);
612 return 1;
613 }
614
open_ubd_file(char * file,struct openflags * openflags,int shared,char ** backing_file_out,int * bitmap_offset_out,unsigned long * bitmap_len_out,int * data_offset_out,int * create_cow_out)615 static int open_ubd_file(char *file, struct openflags *openflags, int shared,
616 char **backing_file_out, int *bitmap_offset_out,
617 unsigned long *bitmap_len_out, int *data_offset_out,
618 int *create_cow_out)
619 {
620 time_t mtime;
621 unsigned long long size;
622 __u32 version, align;
623 char *backing_file;
624 int fd, err, sectorsize, asked_switch, mode = 0644;
625
626 fd = os_open_file(file, *openflags, mode);
627 if (fd < 0) {
628 if ((fd == -ENOENT) && (create_cow_out != NULL))
629 *create_cow_out = 1;
630 if (!openflags->w ||
631 ((fd != -EROFS) && (fd != -EACCES)))
632 return fd;
633 openflags->w = 0;
634 fd = os_open_file(file, *openflags, mode);
635 if (fd < 0)
636 return fd;
637 }
638
639 if (shared)
640 printk(KERN_INFO "Not locking \"%s\" on the host\n", file);
641 else {
642 err = os_lock_file(fd, openflags->w);
643 if (err < 0) {
644 printk(KERN_ERR "Failed to lock '%s', err = %d\n",
645 file, -err);
646 goto out_close;
647 }
648 }
649
650 /* Successful return case! */
651 if (backing_file_out == NULL)
652 return fd;
653
654 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
655 &size, §orsize, &align, bitmap_offset_out);
656 if (err && (*backing_file_out != NULL)) {
657 printk(KERN_ERR "Failed to read COW header from COW file "
658 "\"%s\", errno = %d\n", file, -err);
659 goto out_close;
660 }
661 if (err)
662 return fd;
663
664 asked_switch = path_requires_switch(*backing_file_out, backing_file,
665 file);
666
667 /* Allow switching only if no mismatch. */
668 if (asked_switch && !backing_file_mismatch(*backing_file_out, size,
669 mtime)) {
670 printk(KERN_ERR "Switching backing file to '%s'\n",
671 *backing_file_out);
672 err = write_cow_header(file, fd, *backing_file_out,
673 sectorsize, align, &size);
674 if (err) {
675 printk(KERN_ERR "Switch failed, errno = %d\n", -err);
676 goto out_close;
677 }
678 } else {
679 *backing_file_out = backing_file;
680 err = backing_file_mismatch(*backing_file_out, size, mtime);
681 if (err)
682 goto out_close;
683 }
684
685 cow_sizes(version, size, sectorsize, align, *bitmap_offset_out,
686 bitmap_len_out, data_offset_out);
687
688 return fd;
689 out_close:
690 os_close_file(fd);
691 return err;
692 }
693
create_cow_file(char * cow_file,char * backing_file,struct openflags flags,int sectorsize,int alignment,int * bitmap_offset_out,unsigned long * bitmap_len_out,int * data_offset_out)694 static int create_cow_file(char *cow_file, char *backing_file,
695 struct openflags flags,
696 int sectorsize, int alignment, int *bitmap_offset_out,
697 unsigned long *bitmap_len_out, int *data_offset_out)
698 {
699 int err, fd;
700
701 flags.c = 1;
702 fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL);
703 if (fd < 0) {
704 err = fd;
705 printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n",
706 cow_file, -err);
707 goto out;
708 }
709
710 err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment,
711 bitmap_offset_out, bitmap_len_out,
712 data_offset_out);
713 if (!err)
714 return fd;
715 os_close_file(fd);
716 out:
717 return err;
718 }
719
ubd_close_dev(struct ubd * ubd_dev)720 static void ubd_close_dev(struct ubd *ubd_dev)
721 {
722 os_close_file(ubd_dev->fd);
723 if(ubd_dev->cow.file == NULL)
724 return;
725
726 os_close_file(ubd_dev->cow.fd);
727 vfree(ubd_dev->cow.bitmap);
728 ubd_dev->cow.bitmap = NULL;
729 }
730
ubd_open_dev(struct ubd * ubd_dev)731 static int ubd_open_dev(struct ubd *ubd_dev)
732 {
733 struct openflags flags;
734 char **back_ptr;
735 int err, create_cow, *create_ptr;
736 int fd;
737
738 ubd_dev->openflags = ubd_dev->boot_openflags;
739 create_cow = 0;
740 create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL;
741 back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file;
742
743 fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared,
744 back_ptr, &ubd_dev->cow.bitmap_offset,
745 &ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset,
746 create_ptr);
747
748 if((fd == -ENOENT) && create_cow){
749 fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file,
750 ubd_dev->openflags, 1 << 9, PAGE_SIZE,
751 &ubd_dev->cow.bitmap_offset,
752 &ubd_dev->cow.bitmap_len,
753 &ubd_dev->cow.data_offset);
754 if(fd >= 0){
755 printk(KERN_INFO "Creating \"%s\" as COW file for "
756 "\"%s\"\n", ubd_dev->file, ubd_dev->cow.file);
757 }
758 }
759
760 if(fd < 0){
761 printk("Failed to open '%s', errno = %d\n", ubd_dev->file,
762 -fd);
763 return fd;
764 }
765 ubd_dev->fd = fd;
766
767 if(ubd_dev->cow.file != NULL){
768 blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long));
769
770 err = -ENOMEM;
771 ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len);
772 if(ubd_dev->cow.bitmap == NULL){
773 printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
774 goto error;
775 }
776 flush_tlb_kernel_vm();
777
778 err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
779 ubd_dev->cow.bitmap_offset,
780 ubd_dev->cow.bitmap_len);
781 if(err < 0)
782 goto error;
783
784 flags = ubd_dev->openflags;
785 flags.w = 0;
786 err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL,
787 NULL, NULL, NULL, NULL);
788 if(err < 0) goto error;
789 ubd_dev->cow.fd = err;
790 }
791 return 0;
792 error:
793 os_close_file(ubd_dev->fd);
794 return err;
795 }
796
ubd_device_release(struct device * dev)797 static void ubd_device_release(struct device *dev)
798 {
799 struct ubd *ubd_dev = dev_get_drvdata(dev);
800
801 blk_cleanup_queue(ubd_dev->queue);
802 *ubd_dev = ((struct ubd) DEFAULT_UBD);
803 }
804
ubd_disk_register(int major,u64 size,int unit,struct gendisk ** disk_out)805 static int ubd_disk_register(int major, u64 size, int unit,
806 struct gendisk **disk_out)
807 {
808 struct gendisk *disk;
809
810 disk = alloc_disk(1 << UBD_SHIFT);
811 if(disk == NULL)
812 return -ENOMEM;
813
814 disk->major = major;
815 disk->first_minor = unit << UBD_SHIFT;
816 disk->fops = &ubd_blops;
817 set_capacity(disk, size / 512);
818 if (major == UBD_MAJOR)
819 sprintf(disk->disk_name, "ubd%c", 'a' + unit);
820 else
821 sprintf(disk->disk_name, "ubd_fake%d", unit);
822
823 /* sysfs register (not for ide fake devices) */
824 if (major == UBD_MAJOR) {
825 ubd_devs[unit].pdev.id = unit;
826 ubd_devs[unit].pdev.name = DRIVER_NAME;
827 ubd_devs[unit].pdev.dev.release = ubd_device_release;
828 dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
829 platform_device_register(&ubd_devs[unit].pdev);
830 disk->driverfs_dev = &ubd_devs[unit].pdev.dev;
831 }
832
833 disk->private_data = &ubd_devs[unit];
834 disk->queue = ubd_devs[unit].queue;
835 add_disk(disk);
836
837 *disk_out = disk;
838 return 0;
839 }
840
841 #define ROUND_BLOCK(n) ((n + ((1 << 9) - 1)) & (-1 << 9))
842
ubd_add(int n,char ** error_out)843 static int ubd_add(int n, char **error_out)
844 {
845 struct ubd *ubd_dev = &ubd_devs[n];
846 int err = 0;
847
848 if(ubd_dev->file == NULL)
849 goto out;
850
851 err = ubd_file_size(ubd_dev, &ubd_dev->size);
852 if(err < 0){
853 *error_out = "Couldn't determine size of device's file";
854 goto out;
855 }
856
857 ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
858
859 INIT_LIST_HEAD(&ubd_dev->restart);
860 sg_init_table(ubd_dev->sg, MAX_SG);
861
862 err = -ENOMEM;
863 ubd_dev->queue = blk_init_queue(do_ubd_request, &ubd_dev->lock);
864 if (ubd_dev->queue == NULL) {
865 *error_out = "Failed to initialize device queue";
866 goto out;
867 }
868 ubd_dev->queue->queuedata = ubd_dev;
869
870 blk_queue_max_segments(ubd_dev->queue, MAX_SG);
871 err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
872 if(err){
873 *error_out = "Failed to register device";
874 goto out_cleanup;
875 }
876
877 if (fake_major != UBD_MAJOR)
878 ubd_disk_register(fake_major, ubd_dev->size, n,
879 &fake_gendisk[n]);
880
881 /*
882 * Perhaps this should also be under the "if (fake_major)" above
883 * using the fake_disk->disk_name
884 */
885 if (fake_ide)
886 make_ide_entries(ubd_gendisk[n]->disk_name);
887
888 err = 0;
889 out:
890 return err;
891
892 out_cleanup:
893 blk_cleanup_queue(ubd_dev->queue);
894 goto out;
895 }
896
ubd_config(char * str,char ** error_out)897 static int ubd_config(char *str, char **error_out)
898 {
899 int n, ret;
900
901 /* This string is possibly broken up and stored, so it's only
902 * freed if ubd_setup_common fails, or if only general options
903 * were set.
904 */
905 str = kstrdup(str, GFP_KERNEL);
906 if (str == NULL) {
907 *error_out = "Failed to allocate memory";
908 return -ENOMEM;
909 }
910
911 ret = ubd_setup_common(str, &n, error_out);
912 if (ret)
913 goto err_free;
914
915 if (n == -1) {
916 ret = 0;
917 goto err_free;
918 }
919
920 mutex_lock(&ubd_lock);
921 ret = ubd_add(n, error_out);
922 if (ret)
923 ubd_devs[n].file = NULL;
924 mutex_unlock(&ubd_lock);
925
926 out:
927 return ret;
928
929 err_free:
930 kfree(str);
931 goto out;
932 }
933
ubd_get_config(char * name,char * str,int size,char ** error_out)934 static int ubd_get_config(char *name, char *str, int size, char **error_out)
935 {
936 struct ubd *ubd_dev;
937 int n, len = 0;
938
939 n = parse_unit(&name);
940 if((n >= MAX_DEV) || (n < 0)){
941 *error_out = "ubd_get_config : device number out of range";
942 return -1;
943 }
944
945 ubd_dev = &ubd_devs[n];
946 mutex_lock(&ubd_lock);
947
948 if(ubd_dev->file == NULL){
949 CONFIG_CHUNK(str, size, len, "", 1);
950 goto out;
951 }
952
953 CONFIG_CHUNK(str, size, len, ubd_dev->file, 0);
954
955 if(ubd_dev->cow.file != NULL){
956 CONFIG_CHUNK(str, size, len, ",", 0);
957 CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1);
958 }
959 else CONFIG_CHUNK(str, size, len, "", 1);
960
961 out:
962 mutex_unlock(&ubd_lock);
963 return len;
964 }
965
ubd_id(char ** str,int * start_out,int * end_out)966 static int ubd_id(char **str, int *start_out, int *end_out)
967 {
968 int n;
969
970 n = parse_unit(str);
971 *start_out = 0;
972 *end_out = MAX_DEV - 1;
973 return n;
974 }
975
ubd_remove(int n,char ** error_out)976 static int ubd_remove(int n, char **error_out)
977 {
978 struct gendisk *disk = ubd_gendisk[n];
979 struct ubd *ubd_dev;
980 int err = -ENODEV;
981
982 mutex_lock(&ubd_lock);
983
984 ubd_dev = &ubd_devs[n];
985
986 if(ubd_dev->file == NULL)
987 goto out;
988
989 /* you cannot remove a open disk */
990 err = -EBUSY;
991 if(ubd_dev->count > 0)
992 goto out;
993
994 ubd_gendisk[n] = NULL;
995 if(disk != NULL){
996 del_gendisk(disk);
997 put_disk(disk);
998 }
999
1000 if(fake_gendisk[n] != NULL){
1001 del_gendisk(fake_gendisk[n]);
1002 put_disk(fake_gendisk[n]);
1003 fake_gendisk[n] = NULL;
1004 }
1005
1006 err = 0;
1007 platform_device_unregister(&ubd_dev->pdev);
1008 out:
1009 mutex_unlock(&ubd_lock);
1010 return err;
1011 }
1012
1013 /* All these are called by mconsole in process context and without
1014 * ubd-specific locks. The structure itself is const except for .list.
1015 */
1016 static struct mc_device ubd_mc = {
1017 .list = LIST_HEAD_INIT(ubd_mc.list),
1018 .name = "ubd",
1019 .config = ubd_config,
1020 .get_config = ubd_get_config,
1021 .id = ubd_id,
1022 .remove = ubd_remove,
1023 };
1024
ubd_mc_init(void)1025 static int __init ubd_mc_init(void)
1026 {
1027 mconsole_register_dev(&ubd_mc);
1028 return 0;
1029 }
1030
1031 __initcall(ubd_mc_init);
1032
ubd0_init(void)1033 static int __init ubd0_init(void)
1034 {
1035 struct ubd *ubd_dev = &ubd_devs[0];
1036
1037 mutex_lock(&ubd_lock);
1038 if(ubd_dev->file == NULL)
1039 ubd_dev->file = "root_fs";
1040 mutex_unlock(&ubd_lock);
1041
1042 return 0;
1043 }
1044
1045 __initcall(ubd0_init);
1046
1047 /* Used in ubd_init, which is an initcall */
1048 static struct platform_driver ubd_driver = {
1049 .driver = {
1050 .name = DRIVER_NAME,
1051 },
1052 };
1053
ubd_init(void)1054 static int __init ubd_init(void)
1055 {
1056 char *error;
1057 int i, err;
1058
1059 if (register_blkdev(UBD_MAJOR, "ubd"))
1060 return -1;
1061
1062 if (fake_major != UBD_MAJOR) {
1063 char name[sizeof("ubd_nnn\0")];
1064
1065 snprintf(name, sizeof(name), "ubd_%d", fake_major);
1066 if (register_blkdev(fake_major, "ubd"))
1067 return -1;
1068 }
1069 platform_driver_register(&ubd_driver);
1070 mutex_lock(&ubd_lock);
1071 for (i = 0; i < MAX_DEV; i++){
1072 err = ubd_add(i, &error);
1073 if(err)
1074 printk(KERN_ERR "Failed to initialize ubd device %d :"
1075 "%s\n", i, error);
1076 }
1077 mutex_unlock(&ubd_lock);
1078 return 0;
1079 }
1080
1081 late_initcall(ubd_init);
1082
ubd_driver_init(void)1083 static int __init ubd_driver_init(void){
1084 unsigned long stack;
1085 int err;
1086
1087 /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
1088 if(global_openflags.s){
1089 printk(KERN_INFO "ubd: Synchronous mode\n");
1090 /* Letting ubd=sync be like using ubd#s= instead of ubd#= is
1091 * enough. So use anyway the io thread. */
1092 }
1093 stack = alloc_stack(0, 0);
1094 io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
1095 &thread_fd);
1096 if(io_pid < 0){
1097 printk(KERN_ERR
1098 "ubd : Failed to start I/O thread (errno = %d) - "
1099 "falling back to synchronous I/O\n", -io_pid);
1100 io_pid = -1;
1101 return 0;
1102 }
1103 err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
1104 0, "ubd", ubd_devs);
1105 if(err != 0)
1106 printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
1107 return 0;
1108 }
1109
1110 device_initcall(ubd_driver_init);
1111
ubd_open(struct block_device * bdev,fmode_t mode)1112 static int ubd_open(struct block_device *bdev, fmode_t mode)
1113 {
1114 struct gendisk *disk = bdev->bd_disk;
1115 struct ubd *ubd_dev = disk->private_data;
1116 int err = 0;
1117
1118 mutex_lock(&ubd_mutex);
1119 if(ubd_dev->count == 0){
1120 err = ubd_open_dev(ubd_dev);
1121 if(err){
1122 printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
1123 disk->disk_name, ubd_dev->file, -err);
1124 goto out;
1125 }
1126 }
1127 ubd_dev->count++;
1128 set_disk_ro(disk, !ubd_dev->openflags.w);
1129
1130 /* This should no more be needed. And it didn't work anyway to exclude
1131 * read-write remounting of filesystems.*/
1132 /*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){
1133 if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev);
1134 err = -EROFS;
1135 }*/
1136 out:
1137 mutex_unlock(&ubd_mutex);
1138 return err;
1139 }
1140
ubd_release(struct gendisk * disk,fmode_t mode)1141 static void ubd_release(struct gendisk *disk, fmode_t mode)
1142 {
1143 struct ubd *ubd_dev = disk->private_data;
1144
1145 mutex_lock(&ubd_mutex);
1146 if(--ubd_dev->count == 0)
1147 ubd_close_dev(ubd_dev);
1148 mutex_unlock(&ubd_mutex);
1149 }
1150
cowify_bitmap(__u64 io_offset,int length,unsigned long * cow_mask,__u64 * cow_offset,unsigned long * bitmap,__u64 bitmap_offset,unsigned long * bitmap_words,__u64 bitmap_len)1151 static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
1152 __u64 *cow_offset, unsigned long *bitmap,
1153 __u64 bitmap_offset, unsigned long *bitmap_words,
1154 __u64 bitmap_len)
1155 {
1156 __u64 sector = io_offset >> 9;
1157 int i, update_bitmap = 0;
1158
1159 for(i = 0; i < length >> 9; i++){
1160 if(cow_mask != NULL)
1161 ubd_set_bit(i, (unsigned char *) cow_mask);
1162 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1163 continue;
1164
1165 update_bitmap = 1;
1166 ubd_set_bit(sector + i, (unsigned char *) bitmap);
1167 }
1168
1169 if(!update_bitmap)
1170 return;
1171
1172 *cow_offset = sector / (sizeof(unsigned long) * 8);
1173
1174 /* This takes care of the case where we're exactly at the end of the
1175 * device, and *cow_offset + 1 is off the end. So, just back it up
1176 * by one word. Thanks to Lynn Kerby for the fix and James McMechan
1177 * for the original diagnosis.
1178 */
1179 if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
1180 sizeof(unsigned long)) - 1))
1181 (*cow_offset)--;
1182
1183 bitmap_words[0] = bitmap[*cow_offset];
1184 bitmap_words[1] = bitmap[*cow_offset + 1];
1185
1186 *cow_offset *= sizeof(unsigned long);
1187 *cow_offset += bitmap_offset;
1188 }
1189
cowify_req(struct io_thread_req * req,unsigned long * bitmap,__u64 bitmap_offset,__u64 bitmap_len)1190 static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
1191 __u64 bitmap_offset, __u64 bitmap_len)
1192 {
1193 __u64 sector = req->offset >> 9;
1194 int i;
1195
1196 if(req->length > (sizeof(req->sector_mask) * 8) << 9)
1197 panic("Operation too long");
1198
1199 if(req->op == UBD_READ) {
1200 for(i = 0; i < req->length >> 9; i++){
1201 if(ubd_test_bit(sector + i, (unsigned char *) bitmap))
1202 ubd_set_bit(i, (unsigned char *)
1203 &req->sector_mask);
1204 }
1205 }
1206 else cowify_bitmap(req->offset, req->length, &req->sector_mask,
1207 &req->cow_offset, bitmap, bitmap_offset,
1208 req->bitmap_words, bitmap_len);
1209 }
1210
1211 /* Called with dev->lock held */
prepare_request(struct request * req,struct io_thread_req * io_req,unsigned long long offset,int page_offset,int len,struct page * page)1212 static void prepare_request(struct request *req, struct io_thread_req *io_req,
1213 unsigned long long offset, int page_offset,
1214 int len, struct page *page)
1215 {
1216 struct gendisk *disk = req->rq_disk;
1217 struct ubd *ubd_dev = disk->private_data;
1218
1219 io_req->req = req;
1220 io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd :
1221 ubd_dev->fd;
1222 io_req->fds[1] = ubd_dev->fd;
1223 io_req->cow_offset = -1;
1224 io_req->offset = offset;
1225 io_req->length = len;
1226 io_req->error = 0;
1227 io_req->sector_mask = 0;
1228
1229 io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE;
1230 io_req->offsets[0] = 0;
1231 io_req->offsets[1] = ubd_dev->cow.data_offset;
1232 io_req->buffer = page_address(page) + page_offset;
1233 io_req->sectorsize = 1 << 9;
1234
1235 if(ubd_dev->cow.file != NULL)
1236 cowify_req(io_req, ubd_dev->cow.bitmap,
1237 ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len);
1238
1239 }
1240
1241 /* Called with dev->lock held */
do_ubd_request(struct request_queue * q)1242 static void do_ubd_request(struct request_queue *q)
1243 {
1244 struct io_thread_req *io_req;
1245 struct request *req;
1246 int n;
1247
1248 while(1){
1249 struct ubd *dev = q->queuedata;
1250 if(dev->end_sg == 0){
1251 struct request *req = blk_fetch_request(q);
1252 if(req == NULL)
1253 return;
1254
1255 dev->request = req;
1256 dev->rq_pos = blk_rq_pos(req);
1257 dev->start_sg = 0;
1258 dev->end_sg = blk_rq_map_sg(q, req, dev->sg);
1259 }
1260
1261 req = dev->request;
1262 while(dev->start_sg < dev->end_sg){
1263 struct scatterlist *sg = &dev->sg[dev->start_sg];
1264
1265 io_req = kmalloc(sizeof(struct io_thread_req),
1266 GFP_ATOMIC);
1267 if(io_req == NULL){
1268 if(list_empty(&dev->restart))
1269 list_add(&dev->restart, &restart);
1270 return;
1271 }
1272 prepare_request(req, io_req,
1273 (unsigned long long)dev->rq_pos << 9,
1274 sg->offset, sg->length, sg_page(sg));
1275
1276 n = os_write_file(thread_fd, &io_req,
1277 sizeof(struct io_thread_req *));
1278 if(n != sizeof(struct io_thread_req *)){
1279 if(n != -EAGAIN)
1280 printk("write to io thread failed, "
1281 "errno = %d\n", -n);
1282 else if(list_empty(&dev->restart))
1283 list_add(&dev->restart, &restart);
1284 kfree(io_req);
1285 return;
1286 }
1287
1288 dev->rq_pos += sg->length >> 9;
1289 dev->start_sg++;
1290 }
1291 dev->end_sg = 0;
1292 dev->request = NULL;
1293 }
1294 }
1295
ubd_getgeo(struct block_device * bdev,struct hd_geometry * geo)1296 static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1297 {
1298 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1299
1300 geo->heads = 128;
1301 geo->sectors = 32;
1302 geo->cylinders = ubd_dev->size / (128 * 32 * 512);
1303 return 0;
1304 }
1305
ubd_ioctl(struct block_device * bdev,fmode_t mode,unsigned int cmd,unsigned long arg)1306 static int ubd_ioctl(struct block_device *bdev, fmode_t mode,
1307 unsigned int cmd, unsigned long arg)
1308 {
1309 struct ubd *ubd_dev = bdev->bd_disk->private_data;
1310 u16 ubd_id[ATA_ID_WORDS];
1311
1312 switch (cmd) {
1313 struct cdrom_volctrl volume;
1314 case HDIO_GET_IDENTITY:
1315 memset(&ubd_id, 0, ATA_ID_WORDS * 2);
1316 ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512);
1317 ubd_id[ATA_ID_HEADS] = 128;
1318 ubd_id[ATA_ID_SECTORS] = 32;
1319 if(copy_to_user((char __user *) arg, (char *) &ubd_id,
1320 sizeof(ubd_id)))
1321 return -EFAULT;
1322 return 0;
1323
1324 case CDROMVOLREAD:
1325 if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
1326 return -EFAULT;
1327 volume.channel0 = 255;
1328 volume.channel1 = 255;
1329 volume.channel2 = 255;
1330 volume.channel3 = 255;
1331 if(copy_to_user((char __user *) arg, &volume, sizeof(volume)))
1332 return -EFAULT;
1333 return 0;
1334 }
1335 return -EINVAL;
1336 }
1337
update_bitmap(struct io_thread_req * req)1338 static int update_bitmap(struct io_thread_req *req)
1339 {
1340 int n;
1341
1342 if(req->cow_offset == -1)
1343 return 0;
1344
1345 n = os_seek_file(req->fds[1], req->cow_offset);
1346 if(n < 0){
1347 printk("do_io - bitmap lseek failed : err = %d\n", -n);
1348 return 1;
1349 }
1350
1351 n = os_write_file(req->fds[1], &req->bitmap_words,
1352 sizeof(req->bitmap_words));
1353 if(n != sizeof(req->bitmap_words)){
1354 printk("do_io - bitmap update failed, err = %d fd = %d\n", -n,
1355 req->fds[1]);
1356 return 1;
1357 }
1358
1359 return 0;
1360 }
1361
do_io(struct io_thread_req * req)1362 static void do_io(struct io_thread_req *req)
1363 {
1364 char *buf;
1365 unsigned long len;
1366 int n, nsectors, start, end, bit;
1367 int err;
1368 __u64 off;
1369
1370 nsectors = req->length / req->sectorsize;
1371 start = 0;
1372 do {
1373 bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask);
1374 end = start;
1375 while((end < nsectors) &&
1376 (ubd_test_bit(end, (unsigned char *)
1377 &req->sector_mask) == bit))
1378 end++;
1379
1380 off = req->offset + req->offsets[bit] +
1381 start * req->sectorsize;
1382 len = (end - start) * req->sectorsize;
1383 buf = &req->buffer[start * req->sectorsize];
1384
1385 err = os_seek_file(req->fds[bit], off);
1386 if(err < 0){
1387 printk("do_io - lseek failed : err = %d\n", -err);
1388 req->error = 1;
1389 return;
1390 }
1391 if(req->op == UBD_READ){
1392 n = 0;
1393 do {
1394 buf = &buf[n];
1395 len -= n;
1396 n = os_read_file(req->fds[bit], buf, len);
1397 if (n < 0) {
1398 printk("do_io - read failed, err = %d "
1399 "fd = %d\n", -n, req->fds[bit]);
1400 req->error = 1;
1401 return;
1402 }
1403 } while((n < len) && (n != 0));
1404 if (n < len) memset(&buf[n], 0, len - n);
1405 } else {
1406 n = os_write_file(req->fds[bit], buf, len);
1407 if(n != len){
1408 printk("do_io - write failed err = %d "
1409 "fd = %d\n", -n, req->fds[bit]);
1410 req->error = 1;
1411 return;
1412 }
1413 }
1414
1415 start = end;
1416 } while(start < nsectors);
1417
1418 req->error = update_bitmap(req);
1419 }
1420
1421 /* Changed in start_io_thread, which is serialized by being called only
1422 * from ubd_init, which is an initcall.
1423 */
1424 int kernel_fd = -1;
1425
1426 /* Only changed by the io thread. XXX: currently unused. */
1427 static int io_count = 0;
1428
io_thread(void * arg)1429 int io_thread(void *arg)
1430 {
1431 struct io_thread_req *req;
1432 int n;
1433
1434 ignore_sigwinch_sig();
1435 while(1){
1436 n = os_read_file(kernel_fd, &req,
1437 sizeof(struct io_thread_req *));
1438 if(n != sizeof(struct io_thread_req *)){
1439 if(n < 0)
1440 printk("io_thread - read failed, fd = %d, "
1441 "err = %d\n", kernel_fd, -n);
1442 else {
1443 printk("io_thread - short read, fd = %d, "
1444 "length = %d\n", kernel_fd, n);
1445 }
1446 continue;
1447 }
1448 io_count++;
1449 do_io(req);
1450 n = os_write_file(kernel_fd, &req,
1451 sizeof(struct io_thread_req *));
1452 if(n != sizeof(struct io_thread_req *))
1453 printk("io_thread - write failed, fd = %d, err = %d\n",
1454 kernel_fd, -n);
1455 }
1456
1457 return 0;
1458 }
1459