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Merge branch 'v2.6.37-rc2' into for-2.6.38/core
[mirror_ubuntu-zesty-kernel.git] / fs / partitions / check.c
1 /*
2 * fs/partitions/check.c
3 *
4 * Code extracted from drivers/block/genhd.c
5 * Copyright (C) 1991-1998 Linus Torvalds
6 * Re-organised Feb 1998 Russell King
7 *
8 * We now have independent partition support from the
9 * block drivers, which allows all the partition code to
10 * be grouped in one location, and it to be mostly self
11 * contained.
12 *
13 * Added needed MAJORS for new pairs, {hdi,hdj}, {hdk,hdl}
14 */
15
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/fs.h>
19 #include <linux/slab.h>
20 #include <linux/kmod.h>
21 #include <linux/ctype.h>
22 #include <linux/genhd.h>
23 #include <linux/blktrace_api.h>
24
25 #include "check.h"
26
27 #include "acorn.h"
28 #include "amiga.h"
29 #include "atari.h"
30 #include "ldm.h"
31 #include "mac.h"
32 #include "msdos.h"
33 #include "osf.h"
34 #include "sgi.h"
35 #include "sun.h"
36 #include "ibm.h"
37 #include "ultrix.h"
38 #include "efi.h"
39 #include "karma.h"
40 #include "sysv68.h"
41
42 #ifdef CONFIG_BLK_DEV_MD
43 extern void md_autodetect_dev(dev_t dev);
44 #endif
45
46 int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
47
48 static int (*check_part[])(struct parsed_partitions *) = {
49 /*
50 * Probe partition formats with tables at disk address 0
51 * that also have an ADFS boot block at 0xdc0.
52 */
53 #ifdef CONFIG_ACORN_PARTITION_ICS
54 adfspart_check_ICS,
55 #endif
56 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
57 adfspart_check_POWERTEC,
58 #endif
59 #ifdef CONFIG_ACORN_PARTITION_EESOX
60 adfspart_check_EESOX,
61 #endif
62
63 /*
64 * Now move on to formats that only have partition info at
65 * disk address 0xdc0. Since these may also have stale
66 * PC/BIOS partition tables, they need to come before
67 * the msdos entry.
68 */
69 #ifdef CONFIG_ACORN_PARTITION_CUMANA
70 adfspart_check_CUMANA,
71 #endif
72 #ifdef CONFIG_ACORN_PARTITION_ADFS
73 adfspart_check_ADFS,
74 #endif
75
76 #ifdef CONFIG_EFI_PARTITION
77 efi_partition, /* this must come before msdos */
78 #endif
79 #ifdef CONFIG_SGI_PARTITION
80 sgi_partition,
81 #endif
82 #ifdef CONFIG_LDM_PARTITION
83 ldm_partition, /* this must come before msdos */
84 #endif
85 #ifdef CONFIG_MSDOS_PARTITION
86 msdos_partition,
87 #endif
88 #ifdef CONFIG_OSF_PARTITION
89 osf_partition,
90 #endif
91 #ifdef CONFIG_SUN_PARTITION
92 sun_partition,
93 #endif
94 #ifdef CONFIG_AMIGA_PARTITION
95 amiga_partition,
96 #endif
97 #ifdef CONFIG_ATARI_PARTITION
98 atari_partition,
99 #endif
100 #ifdef CONFIG_MAC_PARTITION
101 mac_partition,
102 #endif
103 #ifdef CONFIG_ULTRIX_PARTITION
104 ultrix_partition,
105 #endif
106 #ifdef CONFIG_IBM_PARTITION
107 ibm_partition,
108 #endif
109 #ifdef CONFIG_KARMA_PARTITION
110 karma_partition,
111 #endif
112 #ifdef CONFIG_SYSV68_PARTITION
113 sysv68_partition,
114 #endif
115 NULL
116 };
117
118 /*
119 * disk_name() is used by partition check code and the genhd driver.
120 * It formats the devicename of the indicated disk into
121 * the supplied buffer (of size at least 32), and returns
122 * a pointer to that same buffer (for convenience).
123 */
124
125 char *disk_name(struct gendisk *hd, int partno, char *buf)
126 {
127 if (!partno)
128 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
129 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
130 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
131 else
132 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
133
134 return buf;
135 }
136
137 const char *bdevname(struct block_device *bdev, char *buf)
138 {
139 return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
140 }
141
142 EXPORT_SYMBOL(bdevname);
143
144 /*
145 * There's very little reason to use this, you should really
146 * have a struct block_device just about everywhere and use
147 * bdevname() instead.
148 */
149 const char *__bdevname(dev_t dev, char *buffer)
150 {
151 scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
152 MAJOR(dev), MINOR(dev));
153 return buffer;
154 }
155
156 EXPORT_SYMBOL(__bdevname);
157
158 static struct parsed_partitions *
159 check_partition(struct gendisk *hd, struct block_device *bdev)
160 {
161 struct parsed_partitions *state;
162 int i, res, err;
163
164 state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
165 if (!state)
166 return NULL;
167 state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
168 if (!state->pp_buf) {
169 kfree(state);
170 return NULL;
171 }
172 state->pp_buf[0] = '\0';
173
174 state->bdev = bdev;
175 disk_name(hd, 0, state->name);
176 snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
177 if (isdigit(state->name[strlen(state->name)-1]))
178 sprintf(state->name, "p");
179
180 state->limit = disk_max_parts(hd);
181 i = res = err = 0;
182 while (!res && check_part[i]) {
183 memset(&state->parts, 0, sizeof(state->parts));
184 res = check_part[i++](state);
185 if (res < 0) {
186 /* We have hit an I/O error which we don't report now.
187 * But record it, and let the others do their job.
188 */
189 err = res;
190 res = 0;
191 }
192
193 }
194 if (res > 0) {
195 printk(KERN_INFO "%s", state->pp_buf);
196
197 free_page((unsigned long)state->pp_buf);
198 return state;
199 }
200 if (state->access_beyond_eod)
201 err = -ENOSPC;
202 if (err)
203 /* The partition is unrecognized. So report I/O errors if there were any */
204 res = err;
205 if (!res)
206 strlcat(state->pp_buf, " unknown partition table\n", PAGE_SIZE);
207 else if (warn_no_part)
208 strlcat(state->pp_buf, " unable to read partition table\n", PAGE_SIZE);
209
210 printk(KERN_INFO "%s", state->pp_buf);
211
212 free_page((unsigned long)state->pp_buf);
213 kfree(state);
214 return ERR_PTR(res);
215 }
216
217 static ssize_t part_partition_show(struct device *dev,
218 struct device_attribute *attr, char *buf)
219 {
220 struct hd_struct *p = dev_to_part(dev);
221
222 return sprintf(buf, "%d\n", p->partno);
223 }
224
225 static ssize_t part_start_show(struct device *dev,
226 struct device_attribute *attr, char *buf)
227 {
228 struct hd_struct *p = dev_to_part(dev);
229
230 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
231 }
232
233 ssize_t part_size_show(struct device *dev,
234 struct device_attribute *attr, char *buf)
235 {
236 struct hd_struct *p = dev_to_part(dev);
237 return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
238 }
239
240 ssize_t part_ro_show(struct device *dev,
241 struct device_attribute *attr, char *buf)
242 {
243 struct hd_struct *p = dev_to_part(dev);
244 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
245 }
246
247 ssize_t part_alignment_offset_show(struct device *dev,
248 struct device_attribute *attr, char *buf)
249 {
250 struct hd_struct *p = dev_to_part(dev);
251 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
252 }
253
254 ssize_t part_discard_alignment_show(struct device *dev,
255 struct device_attribute *attr, char *buf)
256 {
257 struct hd_struct *p = dev_to_part(dev);
258 return sprintf(buf, "%u\n", p->discard_alignment);
259 }
260
261 ssize_t part_stat_show(struct device *dev,
262 struct device_attribute *attr, char *buf)
263 {
264 struct hd_struct *p = dev_to_part(dev);
265 int cpu;
266
267 cpu = part_stat_lock();
268 part_round_stats(cpu, p);
269 part_stat_unlock();
270 return sprintf(buf,
271 "%8lu %8lu %8llu %8u "
272 "%8lu %8lu %8llu %8u "
273 "%8u %8u %8u"
274 "\n",
275 part_stat_read(p, ios[READ]),
276 part_stat_read(p, merges[READ]),
277 (unsigned long long)part_stat_read(p, sectors[READ]),
278 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
279 part_stat_read(p, ios[WRITE]),
280 part_stat_read(p, merges[WRITE]),
281 (unsigned long long)part_stat_read(p, sectors[WRITE]),
282 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
283 part_in_flight(p),
284 jiffies_to_msecs(part_stat_read(p, io_ticks)),
285 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
286 }
287
288 ssize_t part_inflight_show(struct device *dev,
289 struct device_attribute *attr, char *buf)
290 {
291 struct hd_struct *p = dev_to_part(dev);
292
293 return sprintf(buf, "%8u %8u\n", p->in_flight[0], p->in_flight[1]);
294 }
295
296 #ifdef CONFIG_FAIL_MAKE_REQUEST
297 ssize_t part_fail_show(struct device *dev,
298 struct device_attribute *attr, char *buf)
299 {
300 struct hd_struct *p = dev_to_part(dev);
301
302 return sprintf(buf, "%d\n", p->make_it_fail);
303 }
304
305 ssize_t part_fail_store(struct device *dev,
306 struct device_attribute *attr,
307 const char *buf, size_t count)
308 {
309 struct hd_struct *p = dev_to_part(dev);
310 int i;
311
312 if (count > 0 && sscanf(buf, "%d", &i) > 0)
313 p->make_it_fail = (i == 0) ? 0 : 1;
314
315 return count;
316 }
317 #endif
318
319 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
320 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
321 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
322 static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
323 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
324 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
325 NULL);
326 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
327 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
328 #ifdef CONFIG_FAIL_MAKE_REQUEST
329 static struct device_attribute dev_attr_fail =
330 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
331 #endif
332
333 static struct attribute *part_attrs[] = {
334 &dev_attr_partition.attr,
335 &dev_attr_start.attr,
336 &dev_attr_size.attr,
337 &dev_attr_ro.attr,
338 &dev_attr_alignment_offset.attr,
339 &dev_attr_discard_alignment.attr,
340 &dev_attr_stat.attr,
341 &dev_attr_inflight.attr,
342 #ifdef CONFIG_FAIL_MAKE_REQUEST
343 &dev_attr_fail.attr,
344 #endif
345 NULL
346 };
347
348 static struct attribute_group part_attr_group = {
349 .attrs = part_attrs,
350 };
351
352 static const struct attribute_group *part_attr_groups[] = {
353 &part_attr_group,
354 #ifdef CONFIG_BLK_DEV_IO_TRACE
355 &blk_trace_attr_group,
356 #endif
357 NULL
358 };
359
360 static void part_release(struct device *dev)
361 {
362 struct hd_struct *p = dev_to_part(dev);
363 free_part_stats(p);
364 free_part_info(p);
365 kfree(p);
366 }
367
368 struct device_type part_type = {
369 .name = "partition",
370 .groups = part_attr_groups,
371 .release = part_release,
372 };
373
374 static void delete_partition_rcu_cb(struct rcu_head *head)
375 {
376 struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
377
378 part->start_sect = 0;
379 part->nr_sects = 0;
380 part_stat_set_all(part, 0);
381 put_device(part_to_dev(part));
382 }
383
384 void delete_partition(struct gendisk *disk, int partno)
385 {
386 struct disk_part_tbl *ptbl = disk->part_tbl;
387 struct hd_struct *part;
388
389 if (partno >= ptbl->len)
390 return;
391
392 part = ptbl->part[partno];
393 if (!part)
394 return;
395
396 blk_free_devt(part_devt(part));
397 rcu_assign_pointer(ptbl->part[partno], NULL);
398 rcu_assign_pointer(ptbl->last_lookup, NULL);
399 kobject_put(part->holder_dir);
400 device_del(part_to_dev(part));
401
402 call_rcu(&part->rcu_head, delete_partition_rcu_cb);
403 }
404
405 static ssize_t whole_disk_show(struct device *dev,
406 struct device_attribute *attr, char *buf)
407 {
408 return 0;
409 }
410 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
411 whole_disk_show, NULL);
412
413 struct hd_struct *add_partition(struct gendisk *disk, int partno,
414 sector_t start, sector_t len, int flags,
415 struct partition_meta_info *info)
416 {
417 struct hd_struct *p;
418 dev_t devt = MKDEV(0, 0);
419 struct device *ddev = disk_to_dev(disk);
420 struct device *pdev;
421 struct disk_part_tbl *ptbl;
422 const char *dname;
423 int err;
424
425 err = disk_expand_part_tbl(disk, partno);
426 if (err)
427 return ERR_PTR(err);
428 ptbl = disk->part_tbl;
429
430 if (ptbl->part[partno])
431 return ERR_PTR(-EBUSY);
432
433 p = kzalloc(sizeof(*p), GFP_KERNEL);
434 if (!p)
435 return ERR_PTR(-EBUSY);
436
437 if (!init_part_stats(p)) {
438 err = -ENOMEM;
439 goto out_free;
440 }
441 pdev = part_to_dev(p);
442
443 p->start_sect = start;
444 p->alignment_offset =
445 queue_limit_alignment_offset(&disk->queue->limits, start);
446 p->discard_alignment =
447 queue_limit_discard_alignment(&disk->queue->limits, start);
448 p->nr_sects = len;
449 p->partno = partno;
450 p->policy = get_disk_ro(disk);
451
452 if (info) {
453 struct partition_meta_info *pinfo = alloc_part_info(disk);
454 if (!pinfo)
455 goto out_free_stats;
456 memcpy(pinfo, info, sizeof(*info));
457 p->info = pinfo;
458 }
459
460 dname = dev_name(ddev);
461 if (isdigit(dname[strlen(dname) - 1]))
462 dev_set_name(pdev, "%sp%d", dname, partno);
463 else
464 dev_set_name(pdev, "%s%d", dname, partno);
465
466 device_initialize(pdev);
467 pdev->class = &block_class;
468 pdev->type = &part_type;
469 pdev->parent = ddev;
470
471 err = blk_alloc_devt(p, &devt);
472 if (err)
473 goto out_free_info;
474 pdev->devt = devt;
475
476 /* delay uevent until 'holders' subdir is created */
477 dev_set_uevent_suppress(pdev, 1);
478 err = device_add(pdev);
479 if (err)
480 goto out_put;
481
482 err = -ENOMEM;
483 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
484 if (!p->holder_dir)
485 goto out_del;
486
487 dev_set_uevent_suppress(pdev, 0);
488 if (flags & ADDPART_FLAG_WHOLEDISK) {
489 err = device_create_file(pdev, &dev_attr_whole_disk);
490 if (err)
491 goto out_del;
492 }
493
494 /* everything is up and running, commence */
495 rcu_assign_pointer(ptbl->part[partno], p);
496
497 /* suppress uevent if the disk supresses it */
498 if (!dev_get_uevent_suppress(ddev))
499 kobject_uevent(&pdev->kobj, KOBJ_ADD);
500
501 return p;
502
503 out_free_info:
504 free_part_info(p);
505 out_free_stats:
506 free_part_stats(p);
507 out_free:
508 kfree(p);
509 return ERR_PTR(err);
510 out_del:
511 kobject_put(p->holder_dir);
512 device_del(pdev);
513 out_put:
514 put_device(pdev);
515 blk_free_devt(devt);
516 return ERR_PTR(err);
517 }
518
519 /* Not exported, helper to add_disk(). */
520 void register_disk(struct gendisk *disk)
521 {
522 struct device *ddev = disk_to_dev(disk);
523 struct block_device *bdev;
524 struct disk_part_iter piter;
525 struct hd_struct *part;
526 int err;
527
528 ddev->parent = disk->driverfs_dev;
529
530 dev_set_name(ddev, disk->disk_name);
531
532 /* delay uevents, until we scanned partition table */
533 dev_set_uevent_suppress(ddev, 1);
534
535 if (device_add(ddev))
536 return;
537 if (!sysfs_deprecated) {
538 err = sysfs_create_link(block_depr, &ddev->kobj,
539 kobject_name(&ddev->kobj));
540 if (err) {
541 device_del(ddev);
542 return;
543 }
544 }
545 disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
546 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
547
548 /* No minors to use for partitions */
549 if (!disk_partitionable(disk))
550 goto exit;
551
552 /* No such device (e.g., media were just removed) */
553 if (!get_capacity(disk))
554 goto exit;
555
556 bdev = bdget_disk(disk, 0);
557 if (!bdev)
558 goto exit;
559
560 bdev->bd_invalidated = 1;
561 err = blkdev_get(bdev, FMODE_READ);
562 if (err < 0)
563 goto exit;
564 blkdev_put(bdev, FMODE_READ);
565
566 exit:
567 /* announce disk after possible partitions are created */
568 dev_set_uevent_suppress(ddev, 0);
569 kobject_uevent(&ddev->kobj, KOBJ_ADD);
570
571 /* announce possible partitions */
572 disk_part_iter_init(&piter, disk, 0);
573 while ((part = disk_part_iter_next(&piter)))
574 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
575 disk_part_iter_exit(&piter);
576 }
577
578 static bool disk_unlock_native_capacity(struct gendisk *disk)
579 {
580 const struct block_device_operations *bdops = disk->fops;
581
582 if (bdops->unlock_native_capacity &&
583 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
584 printk(KERN_CONT "enabling native capacity\n");
585 bdops->unlock_native_capacity(disk);
586 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
587 return true;
588 } else {
589 printk(KERN_CONT "truncated\n");
590 return false;
591 }
592 }
593
594 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
595 {
596 struct parsed_partitions *state = NULL;
597 struct disk_part_iter piter;
598 struct hd_struct *part;
599 int p, highest, res;
600 rescan:
601 if (state && !IS_ERR(state)) {
602 kfree(state);
603 state = NULL;
604 }
605
606 if (bdev->bd_part_count)
607 return -EBUSY;
608 res = invalidate_partition(disk, 0);
609 if (res)
610 return res;
611
612 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
613 while ((part = disk_part_iter_next(&piter)))
614 delete_partition(disk, part->partno);
615 disk_part_iter_exit(&piter);
616
617 if (disk->fops->revalidate_disk)
618 disk->fops->revalidate_disk(disk);
619 check_disk_size_change(disk, bdev);
620 bdev->bd_invalidated = 0;
621 if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
622 return 0;
623 if (IS_ERR(state)) {
624 /*
625 * I/O error reading the partition table. If any
626 * partition code tried to read beyond EOD, retry
627 * after unlocking native capacity.
628 */
629 if (PTR_ERR(state) == -ENOSPC) {
630 printk(KERN_WARNING "%s: partition table beyond EOD, ",
631 disk->disk_name);
632 if (disk_unlock_native_capacity(disk))
633 goto rescan;
634 }
635 return -EIO;
636 }
637 /*
638 * If any partition code tried to read beyond EOD, try
639 * unlocking native capacity even if partition table is
640 * sucessfully read as we could be missing some partitions.
641 */
642 if (state->access_beyond_eod) {
643 printk(KERN_WARNING
644 "%s: partition table partially beyond EOD, ",
645 disk->disk_name);
646 if (disk_unlock_native_capacity(disk))
647 goto rescan;
648 }
649
650 /* tell userspace that the media / partition table may have changed */
651 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
652
653 /* Detect the highest partition number and preallocate
654 * disk->part_tbl. This is an optimization and not strictly
655 * necessary.
656 */
657 for (p = 1, highest = 0; p < state->limit; p++)
658 if (state->parts[p].size)
659 highest = p;
660
661 disk_expand_part_tbl(disk, highest);
662
663 /* add partitions */
664 for (p = 1; p < state->limit; p++) {
665 sector_t size, from;
666 struct partition_meta_info *info = NULL;
667
668 size = state->parts[p].size;
669 if (!size)
670 continue;
671
672 from = state->parts[p].from;
673 if (from >= get_capacity(disk)) {
674 printk(KERN_WARNING
675 "%s: p%d start %llu is beyond EOD, ",
676 disk->disk_name, p, (unsigned long long) from);
677 if (disk_unlock_native_capacity(disk))
678 goto rescan;
679 continue;
680 }
681
682 if (from + size > get_capacity(disk)) {
683 printk(KERN_WARNING
684 "%s: p%d size %llu extends beyond EOD, ",
685 disk->disk_name, p, (unsigned long long) size);
686
687 if (disk_unlock_native_capacity(disk)) {
688 /* free state and restart */
689 goto rescan;
690 } else {
691 /*
692 * we can not ignore partitions of broken tables
693 * created by for example camera firmware, but
694 * we limit them to the end of the disk to avoid
695 * creating invalid block devices
696 */
697 size = get_capacity(disk) - from;
698 }
699 }
700
701 if (state->parts[p].has_info)
702 info = &state->parts[p].info;
703 part = add_partition(disk, p, from, size,
704 state->parts[p].flags,
705 &state->parts[p].info);
706 if (IS_ERR(part)) {
707 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
708 disk->disk_name, p, -PTR_ERR(part));
709 continue;
710 }
711 #ifdef CONFIG_BLK_DEV_MD
712 if (state->parts[p].flags & ADDPART_FLAG_RAID)
713 md_autodetect_dev(part_to_dev(part)->devt);
714 #endif
715 }
716 kfree(state);
717 return 0;
718 }
719
720 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
721 {
722 struct address_space *mapping = bdev->bd_inode->i_mapping;
723 struct page *page;
724
725 page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
726 NULL);
727 if (!IS_ERR(page)) {
728 if (PageError(page))
729 goto fail;
730 p->v = page;
731 return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
732 fail:
733 page_cache_release(page);
734 }
735 p->v = NULL;
736 return NULL;
737 }
738
739 EXPORT_SYMBOL(read_dev_sector);
740
741 void del_gendisk(struct gendisk *disk)
742 {
743 struct disk_part_iter piter;
744 struct hd_struct *part;
745
746 /* invalidate stuff */
747 disk_part_iter_init(&piter, disk,
748 DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
749 while ((part = disk_part_iter_next(&piter))) {
750 invalidate_partition(disk, part->partno);
751 delete_partition(disk, part->partno);
752 }
753 disk_part_iter_exit(&piter);
754
755 invalidate_partition(disk, 0);
756 blk_free_devt(disk_to_dev(disk)->devt);
757 set_capacity(disk, 0);
758 disk->flags &= ~GENHD_FL_UP;
759 unlink_gendisk(disk);
760 part_stat_set_all(&disk->part0, 0);
761 disk->part0.stamp = 0;
762
763 kobject_put(disk->part0.holder_dir);
764 kobject_put(disk->slave_dir);
765 disk->driverfs_dev = NULL;
766 if (!sysfs_deprecated)
767 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
768 device_del(disk_to_dev(disk));
769 }