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path: root/block/partition-generic.c (plain)
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1/*
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/dax.h>
20#include <linux/blktrace_api.h>
21
22#include "partitions/check.h"
23
24#ifdef CONFIG_BLK_DEV_MD
25extern void md_autodetect_dev(dev_t dev);
26#endif
27
28/*
29 * disk_name() is used by partition check code and the genhd driver.
30 * It formats the devicename of the indicated disk into
31 * the supplied buffer (of size at least 32), and returns
32 * a pointer to that same buffer (for convenience).
33 */
34
35char *disk_name(struct gendisk *hd, int partno, char *buf)
36{
37 if (!partno)
38 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
39 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
40 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
41 else
42 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
43
44 return buf;
45}
46
47const char *bdevname(struct block_device *bdev, char *buf)
48{
49 return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
50}
51
52EXPORT_SYMBOL(bdevname);
53
54/*
55 * There's very little reason to use this, you should really
56 * have a struct block_device just about everywhere and use
57 * bdevname() instead.
58 */
59const char *__bdevname(dev_t dev, char *buffer)
60{
61 scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
62 MAJOR(dev), MINOR(dev));
63 return buffer;
64}
65
66EXPORT_SYMBOL(__bdevname);
67
68static ssize_t part_partition_show(struct device *dev,
69 struct device_attribute *attr, char *buf)
70{
71 struct hd_struct *p = dev_to_part(dev);
72
73 return sprintf(buf, "%d\n", p->partno);
74}
75
76static ssize_t part_start_show(struct device *dev,
77 struct device_attribute *attr, char *buf)
78{
79 struct hd_struct *p = dev_to_part(dev);
80
81 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
82}
83
84ssize_t part_size_show(struct device *dev,
85 struct device_attribute *attr, char *buf)
86{
87 struct hd_struct *p = dev_to_part(dev);
88 return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
89}
90
91static ssize_t part_ro_show(struct device *dev,
92 struct device_attribute *attr, char *buf)
93{
94 struct hd_struct *p = dev_to_part(dev);
95 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
96}
97
98static ssize_t part_alignment_offset_show(struct device *dev,
99 struct device_attribute *attr, char *buf)
100{
101 struct hd_struct *p = dev_to_part(dev);
102 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
103}
104
105static ssize_t part_discard_alignment_show(struct device *dev,
106 struct device_attribute *attr, char *buf)
107{
108 struct hd_struct *p = dev_to_part(dev);
109 return sprintf(buf, "%u\n", p->discard_alignment);
110}
111
112ssize_t part_stat_show(struct device *dev,
113 struct device_attribute *attr, char *buf)
114{
115 struct hd_struct *p = dev_to_part(dev);
116 int cpu;
117
118 cpu = part_stat_lock();
119 part_round_stats(cpu, p);
120 part_stat_unlock();
121 return sprintf(buf,
122 "%8lu %8lu %8llu %8u "
123 "%8lu %8lu %8llu %8u "
124 "%8u %8u %8u"
125 "\n",
126 part_stat_read(p, ios[READ]),
127 part_stat_read(p, merges[READ]),
128 (unsigned long long)part_stat_read(p, sectors[READ]),
129 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
130 part_stat_read(p, ios[WRITE]),
131 part_stat_read(p, merges[WRITE]),
132 (unsigned long long)part_stat_read(p, sectors[WRITE]),
133 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
134 part_in_flight(p),
135 jiffies_to_msecs(part_stat_read(p, io_ticks)),
136 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
137}
138
139ssize_t part_inflight_show(struct device *dev,
140 struct device_attribute *attr, char *buf)
141{
142 struct hd_struct *p = dev_to_part(dev);
143
144 return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
145 atomic_read(&p->in_flight[1]));
146}
147
148#ifdef CONFIG_FAIL_MAKE_REQUEST
149ssize_t part_fail_show(struct device *dev,
150 struct device_attribute *attr, char *buf)
151{
152 struct hd_struct *p = dev_to_part(dev);
153
154 return sprintf(buf, "%d\n", p->make_it_fail);
155}
156
157ssize_t part_fail_store(struct device *dev,
158 struct device_attribute *attr,
159 const char *buf, size_t count)
160{
161 struct hd_struct *p = dev_to_part(dev);
162 int i;
163
164 if (count > 0 && sscanf(buf, "%d", &i) > 0)
165 p->make_it_fail = (i == 0) ? 0 : 1;
166
167 return count;
168}
169#endif
170
171static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
172static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
173static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
174static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
175static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
176static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
177 NULL);
178static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
179static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
180#ifdef CONFIG_FAIL_MAKE_REQUEST
181static struct device_attribute dev_attr_fail =
182 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
183#endif
184
185static struct attribute *part_attrs[] = {
186 &dev_attr_partition.attr,
187 &dev_attr_start.attr,
188 &dev_attr_size.attr,
189 &dev_attr_ro.attr,
190 &dev_attr_alignment_offset.attr,
191 &dev_attr_discard_alignment.attr,
192 &dev_attr_stat.attr,
193 &dev_attr_inflight.attr,
194#ifdef CONFIG_FAIL_MAKE_REQUEST
195 &dev_attr_fail.attr,
196#endif
197 NULL
198};
199
200static struct attribute_group part_attr_group = {
201 .attrs = part_attrs,
202};
203
204static const struct attribute_group *part_attr_groups[] = {
205 &part_attr_group,
206#ifdef CONFIG_BLK_DEV_IO_TRACE
207 &blk_trace_attr_group,
208#endif
209 NULL
210};
211
212static void part_release(struct device *dev)
213{
214 struct hd_struct *p = dev_to_part(dev);
215 blk_free_devt(dev->devt);
216 hd_free_part(p);
217 kfree(p);
218}
219
220static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
221{
222 struct hd_struct *part = dev_to_part(dev);
223
224 add_uevent_var(env, "PARTN=%u", part->partno);
225 if (part->info && part->info->volname[0])
226 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
227 return 0;
228}
229
230struct device_type part_type = {
231 .name = "partition",
232 .groups = part_attr_groups,
233 .release = part_release,
234 .uevent = part_uevent,
235};
236
237static void delete_partition_rcu_cb(struct rcu_head *head)
238{
239 struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
240
241 part->start_sect = 0;
242 part->nr_sects = 0;
243 part_stat_set_all(part, 0);
244 put_device(part_to_dev(part));
245}
246
247void __delete_partition(struct percpu_ref *ref)
248{
249 struct hd_struct *part = container_of(ref, struct hd_struct, ref);
250 call_rcu(&part->rcu_head, delete_partition_rcu_cb);
251}
252
253void delete_partition(struct gendisk *disk, int partno)
254{
255 struct disk_part_tbl *ptbl = disk->part_tbl;
256 struct hd_struct *part;
257
258 if (partno >= ptbl->len)
259 return;
260
261 part = ptbl->part[partno];
262 if (!part)
263 return;
264
265 rcu_assign_pointer(ptbl->part[partno], NULL);
266 rcu_assign_pointer(ptbl->last_lookup, NULL);
267 kobject_put(part->holder_dir);
268 device_del(part_to_dev(part));
269
270 hd_struct_kill(part);
271}
272
273static ssize_t whole_disk_show(struct device *dev,
274 struct device_attribute *attr, char *buf)
275{
276 return 0;
277}
278static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
279 whole_disk_show, NULL);
280
281struct hd_struct *add_partition(struct gendisk *disk, int partno,
282 sector_t start, sector_t len, int flags,
283 struct partition_meta_info *info)
284{
285 struct hd_struct *p;
286 dev_t devt = MKDEV(0, 0);
287 struct device *ddev = disk_to_dev(disk);
288 struct device *pdev;
289 struct disk_part_tbl *ptbl;
290 const char *dname;
291 int err;
292
293 err = disk_expand_part_tbl(disk, partno);
294
295 if (err)
296 return ERR_PTR(err);
297 ptbl = disk->part_tbl;
298
299 if (ptbl->part[partno])
300 return ERR_PTR(-EBUSY);
301
302 p = kzalloc(sizeof(*p), GFP_KERNEL);
303 if (!p)
304 return ERR_PTR(-EBUSY);
305
306 if (!init_part_stats(p)) {
307 err = -ENOMEM;
308 goto out_free;
309 }
310
311 seqcount_init(&p->nr_sects_seq);
312 pdev = part_to_dev(p);
313
314 p->start_sect = start;
315 p->alignment_offset =
316 queue_limit_alignment_offset(&disk->queue->limits, start);
317 p->discard_alignment =
318 queue_limit_discard_alignment(&disk->queue->limits, start);
319 p->nr_sects = len;
320 p->partno = partno;
321 p->policy = get_disk_ro(disk);
322
323 if (info) {
324 struct partition_meta_info *pinfo = alloc_part_info(disk);
325 if (!pinfo) {
326 err = -ENOMEM;
327 goto out_free_stats;
328 }
329 memcpy(pinfo, info, sizeof(*info));
330 p->info = pinfo;
331 }
332
333 dname = dev_name(ddev);
334
335 if (isdigit(dname[strlen(dname) - 1]))
336 dev_set_name(pdev, "%sp%d", dname, partno);
337 else
338 dev_set_name(pdev, "%s%d", dname, partno);
339
340 device_initialize(pdev);
341 pdev->class = &block_class;
342 pdev->type = &part_type;
343 pdev->parent = ddev;
344
345 err = blk_alloc_devt(p, &devt);
346 if (err)
347 goto out_free_info;
348 pdev->devt = devt;
349
350 /* delay uevent until 'holders' subdir is created */
351 dev_set_uevent_suppress(pdev, 1);
352 err = device_add(pdev);
353 if (err)
354 goto out_put;
355
356 err = -ENOMEM;
357 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
358 if (!p->holder_dir)
359 goto out_del;
360
361 dev_set_uevent_suppress(pdev, 0);
362 if (flags & ADDPART_FLAG_WHOLEDISK) {
363 err = device_create_file(pdev, &dev_attr_whole_disk);
364 if (err)
365 goto out_del;
366 }
367
368 err = hd_ref_init(p);
369 if (err) {
370 if (flags & ADDPART_FLAG_WHOLEDISK)
371 goto out_remove_file;
372 goto out_del;
373 }
374
375 /* everything is up and running, commence */
376 rcu_assign_pointer(ptbl->part[partno], p);
377
378 /* suppress uevent if the disk suppresses it */
379 if (!dev_get_uevent_suppress(ddev))
380 kobject_uevent(&pdev->kobj, KOBJ_ADD);
381 return p;
382
383out_free_info:
384 free_part_info(p);
385out_free_stats:
386 free_part_stats(p);
387out_free:
388 kfree(p);
389 return ERR_PTR(err);
390out_remove_file:
391 device_remove_file(pdev, &dev_attr_whole_disk);
392out_del:
393 kobject_put(p->holder_dir);
394 device_del(pdev);
395out_put:
396 put_device(pdev);
397 blk_free_devt(devt);
398 return ERR_PTR(err);
399}
400
401static bool disk_unlock_native_capacity(struct gendisk *disk)
402{
403 const struct block_device_operations *bdops = disk->fops;
404
405 if (bdops->unlock_native_capacity &&
406 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
407 printk(KERN_CONT "enabling native capacity\n");
408 bdops->unlock_native_capacity(disk);
409 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
410 return true;
411 } else {
412 printk(KERN_CONT "truncated\n");
413 return false;
414 }
415}
416
417static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
418{
419 struct disk_part_iter piter;
420 struct hd_struct *part;
421 int res;
422
423 if (bdev->bd_part_count || bdev->bd_super)
424 return -EBUSY;
425 res = invalidate_partition(disk, 0);
426 if (res)
427 return res;
428
429 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
430 while ((part = disk_part_iter_next(&piter)))
431 delete_partition(disk, part->partno);
432 disk_part_iter_exit(&piter);
433
434 return 0;
435}
436
437int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
438{
439 struct parsed_partitions *state = NULL;
440 struct hd_struct *part;
441 int p, highest, res;
442rescan:
443 if (state && !IS_ERR(state)) {
444 free_partitions(state);
445 state = NULL;
446 }
447
448 res = drop_partitions(disk, bdev);
449 if (res)
450 return res;
451
452 if (disk->fops->revalidate_disk)
453 disk->fops->revalidate_disk(disk);
454 check_disk_size_change(disk, bdev);
455 bdev->bd_invalidated = 0;
456 if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
457 return 0;
458 if (IS_ERR(state)) {
459 /*
460 * I/O error reading the partition table. If any
461 * partition code tried to read beyond EOD, retry
462 * after unlocking native capacity.
463 */
464 if (PTR_ERR(state) == -ENOSPC) {
465 printk(KERN_WARNING "%s: partition table beyond EOD, ",
466 disk->disk_name);
467 if (disk_unlock_native_capacity(disk))
468 goto rescan;
469 }
470 return -EIO;
471 }
472 /*
473 * If any partition code tried to read beyond EOD, try
474 * unlocking native capacity even if partition table is
475 * successfully read as we could be missing some partitions.
476 */
477 if (state->access_beyond_eod) {
478 printk(KERN_WARNING
479 "%s: partition table partially beyond EOD, ",
480 disk->disk_name);
481 if (disk_unlock_native_capacity(disk))
482 goto rescan;
483 }
484
485 /* tell userspace that the media / partition table may have changed */
486 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
487
488 /* Detect the highest partition number and preallocate
489 * disk->part_tbl. This is an optimization and not strictly
490 * necessary.
491 */
492 for (p = 1, highest = 0; p < state->limit; p++)
493 if (state->parts[p].size)
494 highest = p;
495
496 disk_expand_part_tbl(disk, highest);
497
498 /* add partitions */
499 for (p = 1; p < state->limit; p++) {
500 sector_t size, from;
501
502 size = state->parts[p].size;
503 if (!size)
504 continue;
505
506 from = state->parts[p].from;
507 if (from >= get_capacity(disk)) {
508 printk(KERN_WARNING
509 "%s: p%d start %llu is beyond EOD, ",
510 disk->disk_name, p, (unsigned long long) from);
511 if (disk_unlock_native_capacity(disk))
512 goto rescan;
513 continue;
514 }
515
516 if (from + size > get_capacity(disk)) {
517 printk(KERN_WARNING
518 "%s: p%d size %llu extends beyond EOD, ",
519 disk->disk_name, p, (unsigned long long) size);
520
521 if (disk_unlock_native_capacity(disk)) {
522 /* free state and restart */
523 goto rescan;
524 } else {
525 /*
526 * we can not ignore partitions of broken tables
527 * created by for example camera firmware, but
528 * we limit them to the end of the disk to avoid
529 * creating invalid block devices
530 */
531 size = get_capacity(disk) - from;
532 }
533 }
534
535 part = add_partition(disk, p, from, size,
536 state->parts[p].flags,
537 &state->parts[p].info);
538 if (IS_ERR(part)) {
539 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
540 disk->disk_name, p, -PTR_ERR(part));
541 continue;
542 }
543#ifdef CONFIG_BLK_DEV_MD
544 if (state->parts[p].flags & ADDPART_FLAG_RAID)
545 md_autodetect_dev(part_to_dev(part)->devt);
546#endif
547 }
548 free_partitions(state);
549 return 0;
550}
551
552int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
553{
554 int res;
555
556 if (!bdev->bd_invalidated)
557 return 0;
558
559 res = drop_partitions(disk, bdev);
560 if (res)
561 return res;
562
563 set_capacity(disk, 0);
564 check_disk_size_change(disk, bdev);
565 bdev->bd_invalidated = 0;
566 /* tell userspace that the media / partition table may have changed */
567 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
568
569 return 0;
570}
571
572static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
573{
574 struct address_space *mapping = bdev->bd_inode->i_mapping;
575
576 return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)),
577 NULL);
578}
579
580unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
581{
582 struct page *page;
583
584 /* don't populate page cache for dax capable devices */
585 if (IS_DAX(bdev->bd_inode))
586 page = read_dax_sector(bdev, n);
587 else
588 page = read_pagecache_sector(bdev, n);
589
590 if (!IS_ERR(page)) {
591 if (PageError(page))
592 goto fail;
593 p->v = page;
594 return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
595fail:
596 put_page(page);
597 }
598 p->v = NULL;
599 return NULL;
600}
601
602EXPORT_SYMBOL(read_dev_sector);
603
generated by cgit at 2024-05-18 15:43:50 (GMT)