separate partition format handling from generic code
[linux-2.6.git] / 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/blktrace_api.h>
20
21 #include "partitions/check.h"
22
23 #ifdef CONFIG_BLK_DEV_MD
24 extern 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
34 char *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
46 const char *bdevname(struct block_device *bdev, char *buf)
47 {
48         return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
49 }
50
51 EXPORT_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  */
58 const 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
65 EXPORT_SYMBOL(__bdevname);
66
67 static 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
75 static 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
83 ssize_t part_size_show(struct device *dev,
84                        struct device_attribute *attr, char *buf)
85 {
86         struct hd_struct *p = dev_to_part(dev);
87         return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
88 }
89
90 static 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
97 static 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
104 static 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
111 ssize_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
138 ssize_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
148 ssize_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
156 ssize_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
170 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
171 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
172 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
173 static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
174 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
175 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
176                    NULL);
177 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
178 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
179 #ifdef CONFIG_FAIL_MAKE_REQUEST
180 static struct device_attribute dev_attr_fail =
181         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
182 #endif
183
184 static 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
199 static struct attribute_group part_attr_group = {
200         .attrs = part_attrs,
201 };
202
203 static 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
211 static 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
219 struct device_type part_type = {
220         .name           = "partition",
221         .groups         = part_attr_groups,
222         .release        = part_release,
223 };
224
225 static 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
235 void __delete_partition(struct hd_struct *part)
236 {
237         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
238 }
239
240 void 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
261 static ssize_t whole_disk_show(struct device *dev,
262                                struct device_attribute *attr, char *buf)
263 {
264         return 0;
265 }
266 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
267                    whole_disk_show, NULL);
268
269 struct 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         }
297         pdev = part_to_dev(p);
298
299         p->start_sect = start;
300         p->alignment_offset =
301                 queue_limit_alignment_offset(&disk->queue->limits, start);
302         p->discard_alignment =
303                 queue_limit_discard_alignment(&disk->queue->limits, start);
304         p->nr_sects = len;
305         p->partno = partno;
306         p->policy = get_disk_ro(disk);
307
308         if (info) {
309                 struct partition_meta_info *pinfo = alloc_part_info(disk);
310                 if (!pinfo)
311                         goto out_free_stats;
312                 memcpy(pinfo, info, sizeof(*info));
313                 p->info = pinfo;
314         }
315
316         dname = dev_name(ddev);
317         if (isdigit(dname[strlen(dname) - 1]))
318                 dev_set_name(pdev, "%sp%d", dname, partno);
319         else
320                 dev_set_name(pdev, "%s%d", dname, partno);
321
322         device_initialize(pdev);
323         pdev->class = &block_class;
324         pdev->type = &part_type;
325         pdev->parent = ddev;
326
327         err = blk_alloc_devt(p, &devt);
328         if (err)
329                 goto out_free_info;
330         pdev->devt = devt;
331
332         /* delay uevent until 'holders' subdir is created */
333         dev_set_uevent_suppress(pdev, 1);
334         err = device_add(pdev);
335         if (err)
336                 goto out_put;
337
338         err = -ENOMEM;
339         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
340         if (!p->holder_dir)
341                 goto out_del;
342
343         dev_set_uevent_suppress(pdev, 0);
344         if (flags & ADDPART_FLAG_WHOLEDISK) {
345                 err = device_create_file(pdev, &dev_attr_whole_disk);
346                 if (err)
347                         goto out_del;
348         }
349
350         /* everything is up and running, commence */
351         rcu_assign_pointer(ptbl->part[partno], p);
352
353         /* suppress uevent if the disk suppresses it */
354         if (!dev_get_uevent_suppress(ddev))
355                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
356
357         hd_ref_init(p);
358         return p;
359
360 out_free_info:
361         free_part_info(p);
362 out_free_stats:
363         free_part_stats(p);
364 out_free:
365         kfree(p);
366         return ERR_PTR(err);
367 out_del:
368         kobject_put(p->holder_dir);
369         device_del(pdev);
370 out_put:
371         put_device(pdev);
372         blk_free_devt(devt);
373         return ERR_PTR(err);
374 }
375
376 static bool disk_unlock_native_capacity(struct gendisk *disk)
377 {
378         const struct block_device_operations *bdops = disk->fops;
379
380         if (bdops->unlock_native_capacity &&
381             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
382                 printk(KERN_CONT "enabling native capacity\n");
383                 bdops->unlock_native_capacity(disk);
384                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
385                 return true;
386         } else {
387                 printk(KERN_CONT "truncated\n");
388                 return false;
389         }
390 }
391
392 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
393 {
394         struct parsed_partitions *state = NULL;
395         struct disk_part_iter piter;
396         struct hd_struct *part;
397         int p, highest, res;
398 rescan:
399         if (state && !IS_ERR(state)) {
400                 kfree(state);
401                 state = NULL;
402         }
403
404         if (bdev->bd_part_count)
405                 return -EBUSY;
406         res = invalidate_partition(disk, 0);
407         if (res)
408                 return res;
409
410         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
411         while ((part = disk_part_iter_next(&piter)))
412                 delete_partition(disk, part->partno);
413         disk_part_iter_exit(&piter);
414
415         if (disk->fops->revalidate_disk)
416                 disk->fops->revalidate_disk(disk);
417         check_disk_size_change(disk, bdev);
418         bdev->bd_invalidated = 0;
419         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
420                 return 0;
421         if (IS_ERR(state)) {
422                 /*
423                  * I/O error reading the partition table.  If any
424                  * partition code tried to read beyond EOD, retry
425                  * after unlocking native capacity.
426                  */
427                 if (PTR_ERR(state) == -ENOSPC) {
428                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
429                                disk->disk_name);
430                         if (disk_unlock_native_capacity(disk))
431                                 goto rescan;
432                 }
433                 return -EIO;
434         }
435         /*
436          * If any partition code tried to read beyond EOD, try
437          * unlocking native capacity even if partition table is
438          * successfully read as we could be missing some partitions.
439          */
440         if (state->access_beyond_eod) {
441                 printk(KERN_WARNING
442                        "%s: partition table partially beyond EOD, ",
443                        disk->disk_name);
444                 if (disk_unlock_native_capacity(disk))
445                         goto rescan;
446         }
447
448         /* tell userspace that the media / partition table may have changed */
449         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
450
451         /* Detect the highest partition number and preallocate
452          * disk->part_tbl.  This is an optimization and not strictly
453          * necessary.
454          */
455         for (p = 1, highest = 0; p < state->limit; p++)
456                 if (state->parts[p].size)
457                         highest = p;
458
459         disk_expand_part_tbl(disk, highest);
460
461         /* add partitions */
462         for (p = 1; p < state->limit; p++) {
463                 sector_t size, from;
464                 struct partition_meta_info *info = NULL;
465
466                 size = state->parts[p].size;
467                 if (!size)
468                         continue;
469
470                 from = state->parts[p].from;
471                 if (from >= get_capacity(disk)) {
472                         printk(KERN_WARNING
473                                "%s: p%d start %llu is beyond EOD, ",
474                                disk->disk_name, p, (unsigned long long) from);
475                         if (disk_unlock_native_capacity(disk))
476                                 goto rescan;
477                         continue;
478                 }
479
480                 if (from + size > get_capacity(disk)) {
481                         printk(KERN_WARNING
482                                "%s: p%d size %llu extends beyond EOD, ",
483                                disk->disk_name, p, (unsigned long long) size);
484
485                         if (disk_unlock_native_capacity(disk)) {
486                                 /* free state and restart */
487                                 goto rescan;
488                         } else {
489                                 /*
490                                  * we can not ignore partitions of broken tables
491                                  * created by for example camera firmware, but
492                                  * we limit them to the end of the disk to avoid
493                                  * creating invalid block devices
494                                  */
495                                 size = get_capacity(disk) - from;
496                         }
497                 }
498
499                 if (state->parts[p].has_info)
500                         info = &state->parts[p].info;
501                 part = add_partition(disk, p, from, size,
502                                      state->parts[p].flags,
503                                      &state->parts[p].info);
504                 if (IS_ERR(part)) {
505                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
506                                disk->disk_name, p, -PTR_ERR(part));
507                         continue;
508                 }
509 #ifdef CONFIG_BLK_DEV_MD
510                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
511                         md_autodetect_dev(part_to_dev(part)->devt);
512 #endif
513         }
514         kfree(state);
515         return 0;
516 }
517
518 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
519 {
520         struct address_space *mapping = bdev->bd_inode->i_mapping;
521         struct page *page;
522
523         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
524                                  NULL);
525         if (!IS_ERR(page)) {
526                 if (PageError(page))
527                         goto fail;
528                 p->v = page;
529                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
530 fail:
531                 page_cache_release(page);
532         }
533         p->v = NULL;
534         return NULL;
535 }
536
537 EXPORT_SYMBOL(read_dev_sector);