Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
[linux-2.6.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_alignment_offset_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, "%llu\n", (unsigned long long)p->alignment_offset);
245 }
246
247 ssize_t part_discard_alignment_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, "%u\n", p->discard_alignment);
252 }
253
254 ssize_t part_stat_show(struct device *dev,
255                        struct device_attribute *attr, char *buf)
256 {
257         struct hd_struct *p = dev_to_part(dev);
258         int cpu;
259
260         cpu = part_stat_lock();
261         part_round_stats(cpu, p);
262         part_stat_unlock();
263         return sprintf(buf,
264                 "%8lu %8lu %8llu %8u "
265                 "%8lu %8lu %8llu %8u "
266                 "%8u %8u %8u"
267                 "\n",
268                 part_stat_read(p, ios[READ]),
269                 part_stat_read(p, merges[READ]),
270                 (unsigned long long)part_stat_read(p, sectors[READ]),
271                 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
272                 part_stat_read(p, ios[WRITE]),
273                 part_stat_read(p, merges[WRITE]),
274                 (unsigned long long)part_stat_read(p, sectors[WRITE]),
275                 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
276                 part_in_flight(p),
277                 jiffies_to_msecs(part_stat_read(p, io_ticks)),
278                 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
279 }
280
281 ssize_t part_inflight_show(struct device *dev,
282                         struct device_attribute *attr, char *buf)
283 {
284         struct hd_struct *p = dev_to_part(dev);
285
286         return sprintf(buf, "%8u %8u\n", p->in_flight[0], p->in_flight[1]);
287 }
288
289 #ifdef CONFIG_FAIL_MAKE_REQUEST
290 ssize_t part_fail_show(struct device *dev,
291                        struct device_attribute *attr, char *buf)
292 {
293         struct hd_struct *p = dev_to_part(dev);
294
295         return sprintf(buf, "%d\n", p->make_it_fail);
296 }
297
298 ssize_t part_fail_store(struct device *dev,
299                         struct device_attribute *attr,
300                         const char *buf, size_t count)
301 {
302         struct hd_struct *p = dev_to_part(dev);
303         int i;
304
305         if (count > 0 && sscanf(buf, "%d", &i) > 0)
306                 p->make_it_fail = (i == 0) ? 0 : 1;
307
308         return count;
309 }
310 #endif
311
312 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
313 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
314 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
315 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
316 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
317                    NULL);
318 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
319 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
320 #ifdef CONFIG_FAIL_MAKE_REQUEST
321 static struct device_attribute dev_attr_fail =
322         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
323 #endif
324
325 static struct attribute *part_attrs[] = {
326         &dev_attr_partition.attr,
327         &dev_attr_start.attr,
328         &dev_attr_size.attr,
329         &dev_attr_alignment_offset.attr,
330         &dev_attr_discard_alignment.attr,
331         &dev_attr_stat.attr,
332         &dev_attr_inflight.attr,
333 #ifdef CONFIG_FAIL_MAKE_REQUEST
334         &dev_attr_fail.attr,
335 #endif
336         NULL
337 };
338
339 static struct attribute_group part_attr_group = {
340         .attrs = part_attrs,
341 };
342
343 static const struct attribute_group *part_attr_groups[] = {
344         &part_attr_group,
345 #ifdef CONFIG_BLK_DEV_IO_TRACE
346         &blk_trace_attr_group,
347 #endif
348         NULL
349 };
350
351 static void part_release(struct device *dev)
352 {
353         struct hd_struct *p = dev_to_part(dev);
354         free_part_stats(p);
355         free_part_info(p);
356         kfree(p);
357 }
358
359 struct device_type part_type = {
360         .name           = "partition",
361         .groups         = part_attr_groups,
362         .release        = part_release,
363 };
364
365 static void delete_partition_rcu_cb(struct rcu_head *head)
366 {
367         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
368         struct gendisk *disk = part_to_disk(part);
369         struct request_queue *q = disk->queue;
370         unsigned long flags;
371
372         part->start_sect = 0;
373         part->nr_sects = 0;
374         part_stat_set_all(part, 0);
375         put_device(part_to_dev(part));
376
377         spin_lock_irqsave(q->queue_lock, flags);
378         elv_quiesce_end(q);
379         spin_unlock_irqrestore(q->queue_lock, flags);
380 }
381
382 void delete_partition(struct gendisk *disk, int partno)
383 {
384         struct disk_part_tbl *ptbl = disk->part_tbl;
385         struct hd_struct *part;
386         struct request_queue *q = disk->queue;
387
388         if (partno >= ptbl->len)
389                 return;
390
391         part = ptbl->part[partno];
392         if (!part)
393                 return;
394
395         blk_free_devt(part_devt(part));
396         rcu_assign_pointer(ptbl->part[partno], NULL);
397         rcu_assign_pointer(ptbl->last_lookup, NULL);
398         kobject_put(part->holder_dir);
399         device_del(part_to_dev(part));
400
401         spin_lock_irq(q->queue_lock);
402         elv_quiesce_start(q);
403         spin_unlock_irq(q->queue_lock);
404
405         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
406 }
407
408 static ssize_t whole_disk_show(struct device *dev,
409                                struct device_attribute *attr, char *buf)
410 {
411         return 0;
412 }
413 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
414                    whole_disk_show, NULL);
415
416 struct hd_struct *add_partition(struct gendisk *disk, int partno,
417                                 sector_t start, sector_t len, int flags,
418                                 struct partition_meta_info *info)
419 {
420         struct hd_struct *p;
421         dev_t devt = MKDEV(0, 0);
422         struct device *ddev = disk_to_dev(disk);
423         struct device *pdev;
424         struct disk_part_tbl *ptbl;
425         const char *dname;
426         int err;
427
428         err = disk_expand_part_tbl(disk, partno);
429         if (err)
430                 return ERR_PTR(err);
431         ptbl = disk->part_tbl;
432
433         if (ptbl->part[partno])
434                 return ERR_PTR(-EBUSY);
435
436         p = kzalloc(sizeof(*p), GFP_KERNEL);
437         if (!p)
438                 return ERR_PTR(-EBUSY);
439
440         if (!init_part_stats(p)) {
441                 err = -ENOMEM;
442                 goto out_free;
443         }
444         pdev = part_to_dev(p);
445
446         p->start_sect = start;
447         p->alignment_offset =
448                 queue_limit_alignment_offset(&disk->queue->limits, start);
449         p->discard_alignment =
450                 queue_limit_discard_alignment(&disk->queue->limits, start);
451         p->nr_sects = len;
452         p->partno = partno;
453         p->policy = get_disk_ro(disk);
454
455         if (info) {
456                 struct partition_meta_info *pinfo = alloc_part_info(disk);
457                 if (!pinfo)
458                         goto out_free_stats;
459                 memcpy(pinfo, info, sizeof(*info));
460                 p->info = pinfo;
461         }
462
463         dname = dev_name(ddev);
464         if (isdigit(dname[strlen(dname) - 1]))
465                 dev_set_name(pdev, "%sp%d", dname, partno);
466         else
467                 dev_set_name(pdev, "%s%d", dname, partno);
468
469         device_initialize(pdev);
470         pdev->class = &block_class;
471         pdev->type = &part_type;
472         pdev->parent = ddev;
473
474         err = blk_alloc_devt(p, &devt);
475         if (err)
476                 goto out_free_info;
477         pdev->devt = devt;
478
479         /* delay uevent until 'holders' subdir is created */
480         dev_set_uevent_suppress(pdev, 1);
481         err = device_add(pdev);
482         if (err)
483                 goto out_put;
484
485         err = -ENOMEM;
486         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
487         if (!p->holder_dir)
488                 goto out_del;
489
490         dev_set_uevent_suppress(pdev, 0);
491         if (flags & ADDPART_FLAG_WHOLEDISK) {
492                 err = device_create_file(pdev, &dev_attr_whole_disk);
493                 if (err)
494                         goto out_del;
495         }
496
497         /* everything is up and running, commence */
498         rcu_assign_pointer(ptbl->part[partno], p);
499
500         /* suppress uevent if the disk supresses it */
501         if (!dev_get_uevent_suppress(ddev))
502                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
503
504         return p;
505
506 out_free_info:
507         free_part_info(p);
508 out_free_stats:
509         free_part_stats(p);
510 out_free:
511         kfree(p);
512         return ERR_PTR(err);
513 out_del:
514         kobject_put(p->holder_dir);
515         device_del(pdev);
516 out_put:
517         put_device(pdev);
518         blk_free_devt(devt);
519         return ERR_PTR(err);
520 }
521
522 /* Not exported, helper to add_disk(). */
523 void register_disk(struct gendisk *disk)
524 {
525         struct device *ddev = disk_to_dev(disk);
526         struct block_device *bdev;
527         struct disk_part_iter piter;
528         struct hd_struct *part;
529         int err;
530
531         ddev->parent = disk->driverfs_dev;
532
533         dev_set_name(ddev, disk->disk_name);
534
535         /* delay uevents, until we scanned partition table */
536         dev_set_uevent_suppress(ddev, 1);
537
538         if (device_add(ddev))
539                 return;
540         if (!sysfs_deprecated) {
541                 err = sysfs_create_link(block_depr, &ddev->kobj,
542                                         kobject_name(&ddev->kobj));
543                 if (err) {
544                         device_del(ddev);
545                         return;
546                 }
547         }
548         disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
549         disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
550
551         /* No minors to use for partitions */
552         if (!disk_partitionable(disk))
553                 goto exit;
554
555         /* No such device (e.g., media were just removed) */
556         if (!get_capacity(disk))
557                 goto exit;
558
559         bdev = bdget_disk(disk, 0);
560         if (!bdev)
561                 goto exit;
562
563         bdev->bd_invalidated = 1;
564         err = blkdev_get(bdev, FMODE_READ);
565         if (err < 0)
566                 goto exit;
567         blkdev_put(bdev, FMODE_READ);
568
569 exit:
570         /* announce disk after possible partitions are created */
571         dev_set_uevent_suppress(ddev, 0);
572         kobject_uevent(&ddev->kobj, KOBJ_ADD);
573
574         /* announce possible partitions */
575         disk_part_iter_init(&piter, disk, 0);
576         while ((part = disk_part_iter_next(&piter)))
577                 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
578         disk_part_iter_exit(&piter);
579 }
580
581 static bool disk_unlock_native_capacity(struct gendisk *disk)
582 {
583         const struct block_device_operations *bdops = disk->fops;
584
585         if (bdops->unlock_native_capacity &&
586             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
587                 printk(KERN_CONT "enabling native capacity\n");
588                 bdops->unlock_native_capacity(disk);
589                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
590                 return true;
591         } else {
592                 printk(KERN_CONT "truncated\n");
593                 return false;
594         }
595 }
596
597 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
598 {
599         struct parsed_partitions *state = NULL;
600         struct disk_part_iter piter;
601         struct hd_struct *part;
602         int p, highest, res;
603 rescan:
604         if (state && !IS_ERR(state)) {
605                 kfree(state);
606                 state = NULL;
607         }
608
609         if (bdev->bd_part_count)
610                 return -EBUSY;
611         res = invalidate_partition(disk, 0);
612         if (res)
613                 return res;
614
615         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
616         while ((part = disk_part_iter_next(&piter)))
617                 delete_partition(disk, part->partno);
618         disk_part_iter_exit(&piter);
619
620         if (disk->fops->revalidate_disk)
621                 disk->fops->revalidate_disk(disk);
622         check_disk_size_change(disk, bdev);
623         bdev->bd_invalidated = 0;
624         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
625                 return 0;
626         if (IS_ERR(state)) {
627                 /*
628                  * I/O error reading the partition table.  If any
629                  * partition code tried to read beyond EOD, retry
630                  * after unlocking native capacity.
631                  */
632                 if (PTR_ERR(state) == -ENOSPC) {
633                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
634                                disk->disk_name);
635                         if (disk_unlock_native_capacity(disk))
636                                 goto rescan;
637                 }
638                 return -EIO;
639         }
640         /*
641          * If any partition code tried to read beyond EOD, try
642          * unlocking native capacity even if partition table is
643          * sucessfully read as we could be missing some partitions.
644          */
645         if (state->access_beyond_eod) {
646                 printk(KERN_WARNING
647                        "%s: partition table partially beyond EOD, ",
648                        disk->disk_name);
649                 if (disk_unlock_native_capacity(disk))
650                         goto rescan;
651         }
652
653         /* tell userspace that the media / partition table may have changed */
654         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
655
656         /* Detect the highest partition number and preallocate
657          * disk->part_tbl.  This is an optimization and not strictly
658          * necessary.
659          */
660         for (p = 1, highest = 0; p < state->limit; p++)
661                 if (state->parts[p].size)
662                         highest = p;
663
664         disk_expand_part_tbl(disk, highest);
665
666         /* add partitions */
667         for (p = 1; p < state->limit; p++) {
668                 sector_t size, from;
669                 struct partition_meta_info *info = NULL;
670
671                 size = state->parts[p].size;
672                 if (!size)
673                         continue;
674
675                 from = state->parts[p].from;
676                 if (from >= get_capacity(disk)) {
677                         printk(KERN_WARNING
678                                "%s: p%d start %llu is beyond EOD, ",
679                                disk->disk_name, p, (unsigned long long) from);
680                         if (disk_unlock_native_capacity(disk))
681                                 goto rescan;
682                         continue;
683                 }
684
685                 if (from + size > get_capacity(disk)) {
686                         printk(KERN_WARNING
687                                "%s: p%d size %llu extends beyond EOD, ",
688                                disk->disk_name, p, (unsigned long long) size);
689
690                         if (disk_unlock_native_capacity(disk)) {
691                                 /* free state and restart */
692                                 goto rescan;
693                         } else {
694                                 /*
695                                  * we can not ignore partitions of broken tables
696                                  * created by for example camera firmware, but
697                                  * we limit them to the end of the disk to avoid
698                                  * creating invalid block devices
699                                  */
700                                 size = get_capacity(disk) - from;
701                         }
702                 }
703
704                 if (state->parts[p].has_info)
705                         info = &state->parts[p].info;
706                 part = add_partition(disk, p, from, size,
707                                      state->parts[p].flags,
708                                      &state->parts[p].info);
709                 if (IS_ERR(part)) {
710                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
711                                disk->disk_name, p, -PTR_ERR(part));
712                         continue;
713                 }
714 #ifdef CONFIG_BLK_DEV_MD
715                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
716                         md_autodetect_dev(part_to_dev(part)->devt);
717 #endif
718         }
719         kfree(state);
720         return 0;
721 }
722
723 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
724 {
725         struct address_space *mapping = bdev->bd_inode->i_mapping;
726         struct page *page;
727
728         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
729                                  NULL);
730         if (!IS_ERR(page)) {
731                 if (PageError(page))
732                         goto fail;
733                 p->v = page;
734                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
735 fail:
736                 page_cache_release(page);
737         }
738         p->v = NULL;
739         return NULL;
740 }
741
742 EXPORT_SYMBOL(read_dev_sector);
743
744 void del_gendisk(struct gendisk *disk)
745 {
746         struct disk_part_iter piter;
747         struct hd_struct *part;
748
749         /* invalidate stuff */
750         disk_part_iter_init(&piter, disk,
751                              DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
752         while ((part = disk_part_iter_next(&piter))) {
753                 invalidate_partition(disk, part->partno);
754                 delete_partition(disk, part->partno);
755         }
756         disk_part_iter_exit(&piter);
757
758         invalidate_partition(disk, 0);
759         blk_free_devt(disk_to_dev(disk)->devt);
760         set_capacity(disk, 0);
761         disk->flags &= ~GENHD_FL_UP;
762         unlink_gendisk(disk);
763         part_stat_set_all(&disk->part0, 0);
764         disk->part0.stamp = 0;
765
766         kobject_put(disk->part0.holder_dir);
767         kobject_put(disk->slave_dir);
768         disk->driverfs_dev = NULL;
769         if (!sysfs_deprecated)
770                 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
771         device_del(disk_to_dev(disk));
772 }