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Al Viro94ea4152011-09-16 00:45:36 -04001/*
2 * Code extracted from drivers/block/genhd.c
3 * Copyright (C) 1991-1998 Linus Torvalds
4 * Re-organised Feb 1998 Russell King
5 *
6 * We now have independent partition support from the
7 * block drivers, which allows all the partition code to
8 * be grouped in one location, and it to be mostly self
9 * contained.
10 */
11
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/fs.h>
15#include <linux/slab.h>
16#include <linux/kmod.h>
17#include <linux/ctype.h>
18#include <linux/genhd.h>
19#include <linux/blktrace_api.h>
20
21#include "partitions/check.h"
22
23#ifdef CONFIG_BLK_DEV_MD
24extern void md_autodetect_dev(dev_t dev);
25#endif
26
27/*
28 * disk_name() is used by partition check code and the genhd driver.
29 * It formats the devicename of the indicated disk into
30 * the supplied buffer (of size at least 32), and returns
31 * a pointer to that same buffer (for convenience).
32 */
33
34char *disk_name(struct gendisk *hd, int partno, char *buf)
35{
36 if (!partno)
37 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
38 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
39 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
40 else
41 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
42
43 return buf;
44}
45
46const char *bdevname(struct block_device *bdev, char *buf)
47{
48 return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
49}
50
51EXPORT_SYMBOL(bdevname);
52
53/*
54 * There's very little reason to use this, you should really
55 * have a struct block_device just about everywhere and use
56 * bdevname() instead.
57 */
58const char *__bdevname(dev_t dev, char *buffer)
59{
60 scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
61 MAJOR(dev), MINOR(dev));
62 return buffer;
63}
64
65EXPORT_SYMBOL(__bdevname);
66
67static ssize_t part_partition_show(struct device *dev,
68 struct device_attribute *attr, char *buf)
69{
70 struct hd_struct *p = dev_to_part(dev);
71
72 return sprintf(buf, "%d\n", p->partno);
73}
74
75static ssize_t part_start_show(struct device *dev,
76 struct device_attribute *attr, char *buf)
77{
78 struct hd_struct *p = dev_to_part(dev);
79
80 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
81}
82
83ssize_t part_size_show(struct device *dev,
84 struct device_attribute *attr, char *buf)
85{
86 struct hd_struct *p = dev_to_part(dev);
Vivek Goyalc83f6bf2012-08-01 12:24:18 +020087 return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
Al Viro94ea4152011-09-16 00:45:36 -040088}
89
90static ssize_t part_ro_show(struct device *dev,
91 struct device_attribute *attr, char *buf)
92{
93 struct hd_struct *p = dev_to_part(dev);
94 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
95}
96
97static ssize_t part_alignment_offset_show(struct device *dev,
98 struct device_attribute *attr, char *buf)
99{
100 struct hd_struct *p = dev_to_part(dev);
101 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
102}
103
104static ssize_t part_discard_alignment_show(struct device *dev,
105 struct device_attribute *attr, char *buf)
106{
107 struct hd_struct *p = dev_to_part(dev);
108 return sprintf(buf, "%u\n", p->discard_alignment);
109}
110
111ssize_t part_stat_show(struct device *dev,
112 struct device_attribute *attr, char *buf)
113{
114 struct hd_struct *p = dev_to_part(dev);
115 int cpu;
116
117 cpu = part_stat_lock();
118 part_round_stats(cpu, p);
119 part_stat_unlock();
120 return sprintf(buf,
121 "%8lu %8lu %8llu %8u "
122 "%8lu %8lu %8llu %8u "
123 "%8u %8u %8u"
124 "\n",
125 part_stat_read(p, ios[READ]),
126 part_stat_read(p, merges[READ]),
127 (unsigned long long)part_stat_read(p, sectors[READ]),
128 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
129 part_stat_read(p, ios[WRITE]),
130 part_stat_read(p, merges[WRITE]),
131 (unsigned long long)part_stat_read(p, sectors[WRITE]),
132 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
133 part_in_flight(p),
134 jiffies_to_msecs(part_stat_read(p, io_ticks)),
135 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
136}
137
138ssize_t part_inflight_show(struct device *dev,
139 struct device_attribute *attr, char *buf)
140{
141 struct hd_struct *p = dev_to_part(dev);
142
143 return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
144 atomic_read(&p->in_flight[1]));
145}
146
147#ifdef CONFIG_FAIL_MAKE_REQUEST
148ssize_t part_fail_show(struct device *dev,
149 struct device_attribute *attr, char *buf)
150{
151 struct hd_struct *p = dev_to_part(dev);
152
153 return sprintf(buf, "%d\n", p->make_it_fail);
154}
155
156ssize_t part_fail_store(struct device *dev,
157 struct device_attribute *attr,
158 const char *buf, size_t count)
159{
160 struct hd_struct *p = dev_to_part(dev);
161 int i;
162
163 if (count > 0 && sscanf(buf, "%d", &i) > 0)
164 p->make_it_fail = (i == 0) ? 0 : 1;
165
166 return count;
167}
168#endif
169
170static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
171static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
172static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
173static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
174static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
175static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
176 NULL);
177static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
178static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
179#ifdef CONFIG_FAIL_MAKE_REQUEST
180static struct device_attribute dev_attr_fail =
181 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
182#endif
183
184static struct attribute *part_attrs[] = {
185 &dev_attr_partition.attr,
186 &dev_attr_start.attr,
187 &dev_attr_size.attr,
188 &dev_attr_ro.attr,
189 &dev_attr_alignment_offset.attr,
190 &dev_attr_discard_alignment.attr,
191 &dev_attr_stat.attr,
192 &dev_attr_inflight.attr,
193#ifdef CONFIG_FAIL_MAKE_REQUEST
194 &dev_attr_fail.attr,
195#endif
196 NULL
197};
198
199static struct attribute_group part_attr_group = {
200 .attrs = part_attrs,
201};
202
203static const struct attribute_group *part_attr_groups[] = {
204 &part_attr_group,
205#ifdef CONFIG_BLK_DEV_IO_TRACE
206 &blk_trace_attr_group,
207#endif
208 NULL
209};
210
211static void part_release(struct device *dev)
212{
213 struct hd_struct *p = dev_to_part(dev);
214 free_part_stats(p);
215 free_part_info(p);
216 kfree(p);
217}
218
219struct device_type part_type = {
220 .name = "partition",
221 .groups = part_attr_groups,
222 .release = part_release,
223};
224
225static void delete_partition_rcu_cb(struct rcu_head *head)
226{
227 struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
228
229 part->start_sect = 0;
230 part->nr_sects = 0;
231 part_stat_set_all(part, 0);
232 put_device(part_to_dev(part));
233}
234
235void __delete_partition(struct hd_struct *part)
236{
237 call_rcu(&part->rcu_head, delete_partition_rcu_cb);
238}
239
240void delete_partition(struct gendisk *disk, int partno)
241{
242 struct disk_part_tbl *ptbl = disk->part_tbl;
243 struct hd_struct *part;
244
245 if (partno >= ptbl->len)
246 return;
247
248 part = ptbl->part[partno];
249 if (!part)
250 return;
251
252 blk_free_devt(part_devt(part));
253 rcu_assign_pointer(ptbl->part[partno], NULL);
254 rcu_assign_pointer(ptbl->last_lookup, NULL);
255 kobject_put(part->holder_dir);
256 device_del(part_to_dev(part));
257
258 hd_struct_put(part);
259}
260
261static ssize_t whole_disk_show(struct device *dev,
262 struct device_attribute *attr, char *buf)
263{
264 return 0;
265}
266static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
267 whole_disk_show, NULL);
268
269struct hd_struct *add_partition(struct gendisk *disk, int partno,
270 sector_t start, sector_t len, int flags,
271 struct partition_meta_info *info)
272{
273 struct hd_struct *p;
274 dev_t devt = MKDEV(0, 0);
275 struct device *ddev = disk_to_dev(disk);
276 struct device *pdev;
277 struct disk_part_tbl *ptbl;
278 const char *dname;
279 int err;
280
281 err = disk_expand_part_tbl(disk, partno);
282 if (err)
283 return ERR_PTR(err);
284 ptbl = disk->part_tbl;
285
286 if (ptbl->part[partno])
287 return ERR_PTR(-EBUSY);
288
289 p = kzalloc(sizeof(*p), GFP_KERNEL);
290 if (!p)
291 return ERR_PTR(-EBUSY);
292
293 if (!init_part_stats(p)) {
294 err = -ENOMEM;
295 goto out_free;
296 }
Vivek Goyalc83f6bf2012-08-01 12:24:18 +0200297
298 seqcount_init(&p->nr_sects_seq);
Al Viro94ea4152011-09-16 00:45:36 -0400299 pdev = part_to_dev(p);
300
301 p->start_sect = start;
302 p->alignment_offset =
303 queue_limit_alignment_offset(&disk->queue->limits, start);
304 p->discard_alignment =
305 queue_limit_discard_alignment(&disk->queue->limits, start);
306 p->nr_sects = len;
307 p->partno = partno;
308 p->policy = get_disk_ro(disk);
309
310 if (info) {
311 struct partition_meta_info *pinfo = alloc_part_info(disk);
312 if (!pinfo)
313 goto out_free_stats;
314 memcpy(pinfo, info, sizeof(*info));
315 p->info = pinfo;
316 }
317
318 dname = dev_name(ddev);
319 if (isdigit(dname[strlen(dname) - 1]))
320 dev_set_name(pdev, "%sp%d", dname, partno);
321 else
322 dev_set_name(pdev, "%s%d", dname, partno);
323
324 device_initialize(pdev);
325 pdev->class = &block_class;
326 pdev->type = &part_type;
327 pdev->parent = ddev;
328
329 err = blk_alloc_devt(p, &devt);
330 if (err)
331 goto out_free_info;
332 pdev->devt = devt;
333
334 /* delay uevent until 'holders' subdir is created */
335 dev_set_uevent_suppress(pdev, 1);
336 err = device_add(pdev);
337 if (err)
338 goto out_put;
339
340 err = -ENOMEM;
341 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
342 if (!p->holder_dir)
343 goto out_del;
344
345 dev_set_uevent_suppress(pdev, 0);
346 if (flags & ADDPART_FLAG_WHOLEDISK) {
347 err = device_create_file(pdev, &dev_attr_whole_disk);
348 if (err)
349 goto out_del;
350 }
351
352 /* everything is up and running, commence */
353 rcu_assign_pointer(ptbl->part[partno], p);
354
355 /* suppress uevent if the disk suppresses it */
356 if (!dev_get_uevent_suppress(ddev))
357 kobject_uevent(&pdev->kobj, KOBJ_ADD);
358
359 hd_ref_init(p);
360 return p;
361
362out_free_info:
363 free_part_info(p);
364out_free_stats:
365 free_part_stats(p);
366out_free:
367 kfree(p);
368 return ERR_PTR(err);
369out_del:
370 kobject_put(p->holder_dir);
371 device_del(pdev);
372out_put:
373 put_device(pdev);
374 blk_free_devt(devt);
375 return ERR_PTR(err);
376}
377
378static bool disk_unlock_native_capacity(struct gendisk *disk)
379{
380 const struct block_device_operations *bdops = disk->fops;
381
382 if (bdops->unlock_native_capacity &&
383 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
384 printk(KERN_CONT "enabling native capacity\n");
385 bdops->unlock_native_capacity(disk);
386 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
387 return true;
388 } else {
389 printk(KERN_CONT "truncated\n");
390 return false;
391 }
392}
393
Jun'ichi Nomurafe316bf2012-03-02 10:38:33 +0100394static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
Al Viro94ea4152011-09-16 00:45:36 -0400395{
Al Viro94ea4152011-09-16 00:45:36 -0400396 struct disk_part_iter piter;
397 struct hd_struct *part;
Jun'ichi Nomurafe316bf2012-03-02 10:38:33 +0100398 int res;
Al Viro94ea4152011-09-16 00:45:36 -0400399
400 if (bdev->bd_part_count)
401 return -EBUSY;
402 res = invalidate_partition(disk, 0);
403 if (res)
404 return res;
405
406 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
407 while ((part = disk_part_iter_next(&piter)))
408 delete_partition(disk, part->partno);
409 disk_part_iter_exit(&piter);
410
Jun'ichi Nomurafe316bf2012-03-02 10:38:33 +0100411 return 0;
412}
413
414int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
415{
416 struct parsed_partitions *state = NULL;
417 struct hd_struct *part;
418 int p, highest, res;
419rescan:
420 if (state && !IS_ERR(state)) {
421 kfree(state);
422 state = NULL;
423 }
424
425 res = drop_partitions(disk, bdev);
426 if (res)
427 return res;
428
Al Viro94ea4152011-09-16 00:45:36 -0400429 if (disk->fops->revalidate_disk)
430 disk->fops->revalidate_disk(disk);
431 check_disk_size_change(disk, bdev);
432 bdev->bd_invalidated = 0;
433 if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
434 return 0;
435 if (IS_ERR(state)) {
436 /*
437 * I/O error reading the partition table. If any
438 * partition code tried to read beyond EOD, retry
439 * after unlocking native capacity.
440 */
441 if (PTR_ERR(state) == -ENOSPC) {
442 printk(KERN_WARNING "%s: partition table beyond EOD, ",
443 disk->disk_name);
444 if (disk_unlock_native_capacity(disk))
445 goto rescan;
446 }
447 return -EIO;
448 }
449 /*
450 * If any partition code tried to read beyond EOD, try
451 * unlocking native capacity even if partition table is
452 * successfully read as we could be missing some partitions.
453 */
454 if (state->access_beyond_eod) {
455 printk(KERN_WARNING
456 "%s: partition table partially beyond EOD, ",
457 disk->disk_name);
458 if (disk_unlock_native_capacity(disk))
459 goto rescan;
460 }
461
462 /* tell userspace that the media / partition table may have changed */
463 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
464
465 /* Detect the highest partition number and preallocate
466 * disk->part_tbl. This is an optimization and not strictly
467 * necessary.
468 */
469 for (p = 1, highest = 0; p < state->limit; p++)
470 if (state->parts[p].size)
471 highest = p;
472
473 disk_expand_part_tbl(disk, highest);
474
475 /* add partitions */
476 for (p = 1; p < state->limit; p++) {
477 sector_t size, from;
478 struct partition_meta_info *info = NULL;
479
480 size = state->parts[p].size;
481 if (!size)
482 continue;
483
484 from = state->parts[p].from;
485 if (from >= get_capacity(disk)) {
486 printk(KERN_WARNING
487 "%s: p%d start %llu is beyond EOD, ",
488 disk->disk_name, p, (unsigned long long) from);
489 if (disk_unlock_native_capacity(disk))
490 goto rescan;
491 continue;
492 }
493
494 if (from + size > get_capacity(disk)) {
495 printk(KERN_WARNING
496 "%s: p%d size %llu extends beyond EOD, ",
497 disk->disk_name, p, (unsigned long long) size);
498
499 if (disk_unlock_native_capacity(disk)) {
500 /* free state and restart */
501 goto rescan;
502 } else {
503 /*
504 * we can not ignore partitions of broken tables
505 * created by for example camera firmware, but
506 * we limit them to the end of the disk to avoid
507 * creating invalid block devices
508 */
509 size = get_capacity(disk) - from;
510 }
511 }
512
513 if (state->parts[p].has_info)
514 info = &state->parts[p].info;
515 part = add_partition(disk, p, from, size,
516 state->parts[p].flags,
517 &state->parts[p].info);
518 if (IS_ERR(part)) {
519 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
520 disk->disk_name, p, -PTR_ERR(part));
521 continue;
522 }
523#ifdef CONFIG_BLK_DEV_MD
524 if (state->parts[p].flags & ADDPART_FLAG_RAID)
525 md_autodetect_dev(part_to_dev(part)->devt);
526#endif
527 }
528 kfree(state);
529 return 0;
530}
531
Jun'ichi Nomurafe316bf2012-03-02 10:38:33 +0100532int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
533{
534 int res;
535
536 if (!bdev->bd_invalidated)
537 return 0;
538
539 res = drop_partitions(disk, bdev);
540 if (res)
541 return res;
542
543 set_capacity(disk, 0);
544 check_disk_size_change(disk, bdev);
545 bdev->bd_invalidated = 0;
546 /* tell userspace that the media / partition table may have changed */
547 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
548
549 return 0;
550}
551
Al Viro94ea4152011-09-16 00:45:36 -0400552unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
553{
554 struct address_space *mapping = bdev->bd_inode->i_mapping;
555 struct page *page;
556
557 page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
558 NULL);
559 if (!IS_ERR(page)) {
560 if (PageError(page))
561 goto fail;
562 p->v = page;
563 return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
564fail:
565 page_cache_release(page);
566 }
567 p->v = NULL;
568 return NULL;
569}
570
571EXPORT_SYMBOL(read_dev_sector);