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/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)part_nr_sects_read(p));
   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 
  298         seqcount_init(&p->nr_sects_seq);
  299         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 
  362 out_free_info:
  363         free_part_info(p);
  364 out_free_stats:
  365         free_part_stats(p);
  366 out_free:
  367         kfree(p);
  368         return ERR_PTR(err);
  369 out_del:
  370         kobject_put(p->holder_dir);
  371         device_del(pdev);
  372 out_put:
  373         put_device(pdev);
  374         blk_free_devt(devt);
  375         return ERR_PTR(err);
  376 }
  377 
  378 static 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 
  394 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
  395 {
  396         struct disk_part_iter piter;
  397         struct hd_struct *part;
  398         int res;
  399 
  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 
  411         return 0;
  412 }
  413 
  414 int 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;
  419 rescan:
  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 
  429         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 
  532 int 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 
  552 unsigned 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);
  564 fail:
  565                 page_cache_release(page);
  566         }
  567         p->v = NULL;
  568         return NULL;
  569 }
  570 
  571 EXPORT_SYMBOL(read_dev_sector);
Cache object: 0289e33250b490f45679a061c924fa0b
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FreeBSD/Linux Kernel Cross Reference sys/block/partition-generic.c

FreeBSD/Linux Kernel Cross Reference
sys/block/partition-generic.c
