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TOMOYO Linux Cross Reference
Linux/block/partition-generic.c

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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
 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 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
434 {
435         struct parsed_partitions *state = NULL;
436         struct hd_struct *part;
437         int p, highest, res;
438 rescan:
439         if (state && !IS_ERR(state)) {
440                 free_partitions(state);
441                 state = NULL;
442         }
443 
444         res = drop_partitions(disk, bdev);
445         if (res)
446                 return res;
447 
448         if (disk->fops->revalidate_disk)
449                 disk->fops->revalidate_disk(disk);
450         blk_integrity_revalidate(disk);
451         check_disk_size_change(disk, bdev);
452         bdev->bd_invalidated = 0;
453         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
454                 return 0;
455         if (IS_ERR(state)) {
456                 /*
457                  * I/O error reading the partition table.  If any
458                  * partition code tried to read beyond EOD, retry
459                  * after unlocking native capacity.
460                  */
461                 if (PTR_ERR(state) == -ENOSPC) {
462                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
463                                disk->disk_name);
464                         if (disk_unlock_native_capacity(disk))
465                                 goto rescan;
466                 }
467                 return -EIO;
468         }
469         /*
470          * If any partition code tried to read beyond EOD, try
471          * unlocking native capacity even if partition table is
472          * successfully read as we could be missing some partitions.
473          */
474         if (state->access_beyond_eod) {
475                 printk(KERN_WARNING
476                        "%s: partition table partially beyond EOD, ",
477                        disk->disk_name);
478                 if (disk_unlock_native_capacity(disk))
479                         goto rescan;
480         }
481 
482         /* tell userspace that the media / partition table may have changed */
483         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
484 
485         /* Detect the highest partition number and preallocate
486          * disk->part_tbl.  This is an optimization and not strictly
487          * necessary.
488          */
489         for (p = 1, highest = 0; p < state->limit; p++)
490                 if (state->parts[p].size)
491                         highest = p;
492 
493         disk_expand_part_tbl(disk, highest);
494 
495         /* add partitions */
496         for (p = 1; p < state->limit; p++) {
497                 sector_t size, from;
498 
499                 size = state->parts[p].size;
500                 if (!size)
501                         continue;
502 
503                 from = state->parts[p].from;
504                 if (from >= get_capacity(disk)) {
505                         printk(KERN_WARNING
506                                "%s: p%d start %llu is beyond EOD, ",
507                                disk->disk_name, p, (unsigned long long) from);
508                         if (disk_unlock_native_capacity(disk))
509                                 goto rescan;
510                         continue;
511                 }
512 
513                 if (from + size > get_capacity(disk)) {
514                         printk(KERN_WARNING
515                                "%s: p%d size %llu extends beyond EOD, ",
516                                disk->disk_name, p, (unsigned long long) size);
517 
518                         if (disk_unlock_native_capacity(disk)) {
519                                 /* free state and restart */
520                                 goto rescan;
521                         } else {
522                                 /*
523                                  * we can not ignore partitions of broken tables
524                                  * created by for example camera firmware, but
525                                  * we limit them to the end of the disk to avoid
526                                  * creating invalid block devices
527                                  */
528                                 size = get_capacity(disk) - from;
529                         }
530                 }
531 
532                 part = add_partition(disk, p, from, size,
533                                      state->parts[p].flags,
534                                      &state->parts[p].info);
535                 if (IS_ERR(part)) {
536                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
537                                disk->disk_name, p, -PTR_ERR(part));
538                         continue;
539                 }
540 #ifdef CONFIG_BLK_DEV_MD
541                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
542                         md_autodetect_dev(part_to_dev(part)->devt);
543 #endif
544         }
545         free_partitions(state);
546         return 0;
547 }
548 
549 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
550 {
551         int res;
552 
553         if (!bdev->bd_invalidated)
554                 return 0;
555 
556         res = drop_partitions(disk, bdev);
557         if (res)
558                 return res;
559 
560         set_capacity(disk, 0);
561         check_disk_size_change(disk, bdev);
562         bdev->bd_invalidated = 0;
563         /* tell userspace that the media / partition table may have changed */
564         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
565 
566         return 0;
567 }
568 
569 static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
570 {
571         struct address_space *mapping = bdev->bd_inode->i_mapping;
572 
573         return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)),
574                                  NULL);
575 }
576 
577 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
578 {
579         struct page *page;
580 
581         /* don't populate page cache for dax capable devices */
582         if (IS_DAX(bdev->bd_inode))
583                 page = read_dax_sector(bdev, n);
584         else
585                 page = read_pagecache_sector(bdev, n);
586 
587         if (!IS_ERR(page)) {
588                 if (PageError(page))
589                         goto fail;
590                 p->v = page;
591                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
592 fail:
593                 put_page(page);
594         }
595         p->v = NULL;
596         return NULL;
597 }
598 
599 EXPORT_SYMBOL(read_dev_sector);
600 

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