Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/block/partition-generic.c

  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
 25 extern 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 
 35 char *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 
 47 const char *bdevname(struct block_device *bdev, char *buf)
 48 {
 49         return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
 50 }
 51 
 52 EXPORT_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  */
 59 const 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 
 66 EXPORT_SYMBOL(__bdevname);
 67 
 68 static 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 
 76 static 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 
 84 ssize_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 
 91 static 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 
 98 static 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 
105 static 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 
112 ssize_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 
139 ssize_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
149 ssize_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 
157 ssize_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 
171 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
172 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
173 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
174 static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
175 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
176 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
177                    NULL);
178 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
179 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
180 #ifdef CONFIG_FAIL_MAKE_REQUEST
181 static struct device_attribute dev_attr_fail =
182         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
183 #endif
184 
185 static 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 
200 static struct attribute_group part_attr_group = {
201         .attrs = part_attrs,
202 };
203 
204 static 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 
212 static 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 
220 static 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 
230 struct device_type part_type = {
231         .name           = "partition",
232         .groups         = part_attr_groups,
233         .release        = part_release,
234         .uevent         = part_uevent,
235 };
236 
237 static 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 
247 void __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 
253 void 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 
273 static ssize_t whole_disk_show(struct device *dev,
274                                struct device_attribute *attr, char *buf)
275 {
276         return 0;
277 }
278 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
279                    whole_disk_show, NULL);
280 
281 struct 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         if (err)
295                 return ERR_PTR(err);
296         ptbl = disk->part_tbl;
297 
298         if (ptbl->part[partno])
299                 return ERR_PTR(-EBUSY);
300 
301         p = kzalloc(sizeof(*p), GFP_KERNEL);
302         if (!p)
303                 return ERR_PTR(-EBUSY);
304 
305         if (!init_part_stats(p)) {
306                 err = -ENOMEM;
307                 goto out_free;
308         }
309 
310         seqcount_init(&p->nr_sects_seq);
311         pdev = part_to_dev(p);
312 
313         p->start_sect = start;
314         p->alignment_offset =
315                 queue_limit_alignment_offset(&disk->queue->limits, start);
316         p->discard_alignment =
317                 queue_limit_discard_alignment(&disk->queue->limits, start);
318         p->nr_sects = len;
319         p->partno = partno;
320         p->policy = get_disk_ro(disk);
321 
322         if (info) {
323                 struct partition_meta_info *pinfo = alloc_part_info(disk);
324                 if (!pinfo)
325                         goto out_free_stats;
326                 memcpy(pinfo, info, sizeof(*info));
327                 p->info = pinfo;
328         }
329 
330         dname = dev_name(ddev);
331         if (isdigit(dname[strlen(dname) - 1]))
332                 dev_set_name(pdev, "%sp%d", dname, partno);
333         else
334                 dev_set_name(pdev, "%s%d", dname, partno);
335 
336         device_initialize(pdev);
337         pdev->class = &block_class;
338         pdev->type = &part_type;
339         pdev->parent = ddev;
340 
341         err = blk_alloc_devt(p, &devt);
342         if (err)
343                 goto out_free_info;
344         pdev->devt = devt;
345 
346         /* delay uevent until 'holders' subdir is created */
347         dev_set_uevent_suppress(pdev, 1);
348         err = device_add(pdev);
349         if (err)
350                 goto out_put;
351 
352         err = -ENOMEM;
353         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
354         if (!p->holder_dir)
355                 goto out_del;
356 
357         dev_set_uevent_suppress(pdev, 0);
358         if (flags & ADDPART_FLAG_WHOLEDISK) {
359                 err = device_create_file(pdev, &dev_attr_whole_disk);
360                 if (err)
361                         goto out_del;
362         }
363 
364         err = hd_ref_init(p);
365         if (err) {
366                 if (flags & ADDPART_FLAG_WHOLEDISK)
367                         goto out_remove_file;
368                 goto out_del;
369         }
370 
371         /* everything is up and running, commence */
372         rcu_assign_pointer(ptbl->part[partno], p);
373 
374         /* suppress uevent if the disk suppresses it */
375         if (!dev_get_uevent_suppress(ddev))
376                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
377         return p;
378 
379 out_free_info:
380         free_part_info(p);
381 out_free_stats:
382         free_part_stats(p);
383 out_free:
384         kfree(p);
385         return ERR_PTR(err);
386 out_remove_file:
387         device_remove_file(pdev, &dev_attr_whole_disk);
388 out_del:
389         kobject_put(p->holder_dir);
390         device_del(pdev);
391 out_put:
392         put_device(pdev);
393         blk_free_devt(devt);
394         return ERR_PTR(err);
395 }
396 
397 static bool disk_unlock_native_capacity(struct gendisk *disk)
398 {
399         const struct block_device_operations *bdops = disk->fops;
400 
401         if (bdops->unlock_native_capacity &&
402             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
403                 printk(KERN_CONT "enabling native capacity\n");
404                 bdops->unlock_native_capacity(disk);
405                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
406                 return true;
407         } else {
408                 printk(KERN_CONT "truncated\n");
409                 return false;
410         }
411 }
412 
413 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
414 {
415         struct disk_part_iter piter;
416         struct hd_struct *part;
417         int res;
418 
419         if (bdev->bd_part_count || bdev->bd_super)
420                 return -EBUSY;
421         res = invalidate_partition(disk, 0);
422         if (res)
423                 return res;
424 
425         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
426         while ((part = disk_part_iter_next(&piter)))
427                 delete_partition(disk, part->partno);
428         disk_part_iter_exit(&piter);
429 
430         return 0;
431 }
432 
433 static bool part_zone_aligned(struct gendisk *disk,
434                               struct block_device *bdev,
435                               sector_t from, sector_t size)
436 {
437         unsigned int zone_sectors = bdev_zone_sectors(bdev);
438 
439         /*
440          * If this function is called, then the disk is a zoned block device
441          * (host-aware or host-managed). This can be detected even if the
442          * zoned block device support is disabled (CONFIG_BLK_DEV_ZONED not
443          * set). In this case, however, only host-aware devices will be seen
444          * as a block device is not created for host-managed devices. Without
445          * zoned block device support, host-aware drives can still be used as
446          * regular block devices (no zone operation) and their zone size will
447          * be reported as 0. Allow this case.
448          */
449         if (!zone_sectors)
450                 return true;
451 
452         /*
453          * Check partition start and size alignement. If the drive has a
454          * smaller last runt zone, ignore it and allow the partition to
455          * use it. Check the zone size too: it should be a power of 2 number
456          * of sectors.
457          */
458         if (WARN_ON_ONCE(!is_power_of_2(zone_sectors))) {
459                 u32 rem;
460 
461                 div_u64_rem(from, zone_sectors, &rem);
462                 if (rem)
463                         return false;
464                 if ((from + size) < get_capacity(disk)) {
465                         div_u64_rem(size, zone_sectors, &rem);
466                         if (rem)
467                                 return false;
468                 }
469 
470         } else {
471 
472                 if (from & (zone_sectors - 1))
473                         return false;
474                 if ((from + size) < get_capacity(disk) &&
475                     (size & (zone_sectors - 1)))
476                         return false;
477 
478         }
479 
480         return true;
481 }
482 
483 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
484 {
485         struct parsed_partitions *state = NULL;
486         struct hd_struct *part;
487         int p, highest, res;
488 rescan:
489         if (state && !IS_ERR(state)) {
490                 free_partitions(state);
491                 state = NULL;
492         }
493 
494         res = drop_partitions(disk, bdev);
495         if (res)
496                 return res;
497 
498         if (disk->fops->revalidate_disk)
499                 disk->fops->revalidate_disk(disk);
500         blk_integrity_revalidate(disk);
501         check_disk_size_change(disk, bdev);
502         bdev->bd_invalidated = 0;
503         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
504                 return 0;
505         if (IS_ERR(state)) {
506                 /*
507                  * I/O error reading the partition table.  If any
508                  * partition code tried to read beyond EOD, retry
509                  * after unlocking native capacity.
510                  */
511                 if (PTR_ERR(state) == -ENOSPC) {
512                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
513                                disk->disk_name);
514                         if (disk_unlock_native_capacity(disk))
515                                 goto rescan;
516                 }
517                 return -EIO;
518         }
519         /*
520          * If any partition code tried to read beyond EOD, try
521          * unlocking native capacity even if partition table is
522          * successfully read as we could be missing some partitions.
523          */
524         if (state->access_beyond_eod) {
525                 printk(KERN_WARNING
526                        "%s: partition table partially beyond EOD, ",
527                        disk->disk_name);
528                 if (disk_unlock_native_capacity(disk))
529                         goto rescan;
530         }
531 
532         /* tell userspace that the media / partition table may have changed */
533         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
534 
535         /* Detect the highest partition number and preallocate
536          * disk->part_tbl.  This is an optimization and not strictly
537          * necessary.
538          */
539         for (p = 1, highest = 0; p < state->limit; p++)
540                 if (state->parts[p].size)
541                         highest = p;
542 
543         disk_expand_part_tbl(disk, highest);
544 
545         /* add partitions */
546         for (p = 1; p < state->limit; p++) {
547                 sector_t size, from;
548 
549                 size = state->parts[p].size;
550                 if (!size)
551                         continue;
552 
553                 from = state->parts[p].from;
554                 if (from >= get_capacity(disk)) {
555                         printk(KERN_WARNING
556                                "%s: p%d start %llu is beyond EOD, ",
557                                disk->disk_name, p, (unsigned long long) from);
558                         if (disk_unlock_native_capacity(disk))
559                                 goto rescan;
560                         continue;
561                 }
562 
563                 if (from + size > get_capacity(disk)) {
564                         printk(KERN_WARNING
565                                "%s: p%d size %llu extends beyond EOD, ",
566                                disk->disk_name, p, (unsigned long long) size);
567 
568                         if (disk_unlock_native_capacity(disk)) {
569                                 /* free state and restart */
570                                 goto rescan;
571                         } else {
572                                 /*
573                                  * we can not ignore partitions of broken tables
574                                  * created by for example camera firmware, but
575                                  * we limit them to the end of the disk to avoid
576                                  * creating invalid block devices
577                                  */
578                                 size = get_capacity(disk) - from;
579                         }
580                 }
581 
582                 /*
583                  * On a zoned block device, partitions should be aligned on the
584                  * device zone size (i.e. zone boundary crossing not allowed).
585                  * Otherwise, resetting the write pointer of the last zone of
586                  * one partition may impact the following partition.
587                  */
588                 if (bdev_is_zoned(bdev) &&
589                     !part_zone_aligned(disk, bdev, from, size)) {
590                         printk(KERN_WARNING
591                                "%s: p%d start %llu+%llu is not zone aligned\n",
592                                disk->disk_name, p, (unsigned long long) from,
593                                (unsigned long long) size);
594                         continue;
595                 }
596 
597                 part = add_partition(disk, p, from, size,
598                                      state->parts[p].flags,
599                                      &state->parts[p].info);
600                 if (IS_ERR(part)) {
601                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
602                                disk->disk_name, p, -PTR_ERR(part));
603                         continue;
604                 }
605 #ifdef CONFIG_BLK_DEV_MD
606                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
607                         md_autodetect_dev(part_to_dev(part)->devt);
608 #endif
609         }
610         free_partitions(state);
611         return 0;
612 }
613 
614 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
615 {
616         int res;
617 
618         if (!bdev->bd_invalidated)
619                 return 0;
620 
621         res = drop_partitions(disk, bdev);
622         if (res)
623                 return res;
624 
625         set_capacity(disk, 0);
626         check_disk_size_change(disk, bdev);
627         bdev->bd_invalidated = 0;
628         /* tell userspace that the media / partition table may have changed */
629         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
630 
631         return 0;
632 }
633 
634 static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
635 {
636         struct address_space *mapping = bdev->bd_inode->i_mapping;
637 
638         return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)),
639                                  NULL);
640 }
641 
642 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
643 {
644         struct page *page;
645 
646         /* don't populate page cache for dax capable devices */
647         if (IS_DAX(bdev->bd_inode))
648                 page = read_dax_sector(bdev, n);
649         else
650                 page = read_pagecache_sector(bdev, n);
651 
652         if (!IS_ERR(page)) {
653                 if (PageError(page))
654                         goto fail;
655                 p->v = page;
656                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
657 fail:
658                 put_page(page);
659         }
660         p->v = NULL;
661         return NULL;
662 }
663 
664 EXPORT_SYMBOL(read_dev_sector);
665 

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