linux/fs/partitions/check.c
Tejun Heo 0fc71e3d65 block: add partition attribute for partition number
With extended devt, finding out the partition number becomes a bit
more challenging as subtracting the minor number from that of the
parent device doesn't work anymore.  The only thing left is parsing
the partition name which is brittle and not exactly universal (some
have '-' between the device name and partition number while others
don't).  This patch introduced partition attribute which contains the
partition number of the device.  This should make finding partitions
and its index easier.

This problem and solution were suggested by H. Peter Anvin.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-17 08:46:56 +02:00

635 lines
15 KiB
C

/*
* fs/partitions/check.c
*
* Code extracted from drivers/block/genhd.c
* Copyright (C) 1991-1998 Linus Torvalds
* Re-organised Feb 1998 Russell King
*
* We now have independent partition support from the
* block drivers, which allows all the partition code to
* be grouped in one location, and it to be mostly self
* contained.
*
* Added needed MAJORS for new pairs, {hdi,hdj}, {hdk,hdl}
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/kmod.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
#include "check.h"
#include "acorn.h"
#include "amiga.h"
#include "atari.h"
#include "ldm.h"
#include "mac.h"
#include "msdos.h"
#include "osf.h"
#include "sgi.h"
#include "sun.h"
#include "ibm.h"
#include "ultrix.h"
#include "efi.h"
#include "karma.h"
#include "sysv68.h"
#ifdef CONFIG_BLK_DEV_MD
extern void md_autodetect_dev(dev_t dev);
#endif
int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
static int (*check_part[])(struct parsed_partitions *, struct block_device *) = {
/*
* Probe partition formats with tables at disk address 0
* that also have an ADFS boot block at 0xdc0.
*/
#ifdef CONFIG_ACORN_PARTITION_ICS
adfspart_check_ICS,
#endif
#ifdef CONFIG_ACORN_PARTITION_POWERTEC
adfspart_check_POWERTEC,
#endif
#ifdef CONFIG_ACORN_PARTITION_EESOX
adfspart_check_EESOX,
#endif
/*
* Now move on to formats that only have partition info at
* disk address 0xdc0. Since these may also have stale
* PC/BIOS partition tables, they need to come before
* the msdos entry.
*/
#ifdef CONFIG_ACORN_PARTITION_CUMANA
adfspart_check_CUMANA,
#endif
#ifdef CONFIG_ACORN_PARTITION_ADFS
adfspart_check_ADFS,
#endif
#ifdef CONFIG_EFI_PARTITION
efi_partition, /* this must come before msdos */
#endif
#ifdef CONFIG_SGI_PARTITION
sgi_partition,
#endif
#ifdef CONFIG_LDM_PARTITION
ldm_partition, /* this must come before msdos */
#endif
#ifdef CONFIG_MSDOS_PARTITION
msdos_partition,
#endif
#ifdef CONFIG_OSF_PARTITION
osf_partition,
#endif
#ifdef CONFIG_SUN_PARTITION
sun_partition,
#endif
#ifdef CONFIG_AMIGA_PARTITION
amiga_partition,
#endif
#ifdef CONFIG_ATARI_PARTITION
atari_partition,
#endif
#ifdef CONFIG_MAC_PARTITION
mac_partition,
#endif
#ifdef CONFIG_ULTRIX_PARTITION
ultrix_partition,
#endif
#ifdef CONFIG_IBM_PARTITION
ibm_partition,
#endif
#ifdef CONFIG_KARMA_PARTITION
karma_partition,
#endif
#ifdef CONFIG_SYSV68_PARTITION
sysv68_partition,
#endif
NULL
};
/*
* disk_name() is used by partition check code and the genhd driver.
* It formats the devicename of the indicated disk into
* the supplied buffer (of size at least 32), and returns
* a pointer to that same buffer (for convenience).
*/
char *disk_name(struct gendisk *hd, int partno, char *buf)
{
if (!partno)
snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
else
snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
return buf;
}
const char *bdevname(struct block_device *bdev, char *buf)
{
return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
}
EXPORT_SYMBOL(bdevname);
/*
* There's very little reason to use this, you should really
* have a struct block_device just about everywhere and use
* bdevname() instead.
*/
const char *__bdevname(dev_t dev, char *buffer)
{
scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
MAJOR(dev), MINOR(dev));
return buffer;
}
EXPORT_SYMBOL(__bdevname);
static struct parsed_partitions *
check_partition(struct gendisk *hd, struct block_device *bdev)
{
struct parsed_partitions *state;
int i, res, err;
state = kmalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
if (!state)
return NULL;
disk_name(hd, 0, state->name);
printk(KERN_INFO " %s:", state->name);
if (isdigit(state->name[strlen(state->name)-1]))
sprintf(state->name, "p");
state->limit = disk_max_parts(hd);
i = res = err = 0;
while (!res && check_part[i]) {
memset(&state->parts, 0, sizeof(state->parts));
res = check_part[i++](state, bdev);
if (res < 0) {
/* We have hit an I/O error which we don't report now.
* But record it, and let the others do their job.
*/
err = res;
res = 0;
}
}
if (res > 0)
return state;
if (err)
/* The partition is unrecognized. So report I/O errors if there were any */
res = err;
if (!res)
printk(" unknown partition table\n");
else if (warn_no_part)
printk(" unable to read partition table\n");
kfree(state);
return ERR_PTR(res);
}
static ssize_t part_partition_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%d\n", p->partno);
}
static ssize_t part_start_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
}
ssize_t part_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
}
ssize_t part_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
int cpu;
cpu = part_stat_lock();
part_round_stats(cpu, p);
part_stat_unlock();
return sprintf(buf,
"%8lu %8lu %8llu %8u "
"%8lu %8lu %8llu %8u "
"%8u %8u %8u"
"\n",
part_stat_read(p, ios[READ]),
part_stat_read(p, merges[READ]),
(unsigned long long)part_stat_read(p, sectors[READ]),
jiffies_to_msecs(part_stat_read(p, ticks[READ])),
part_stat_read(p, ios[WRITE]),
part_stat_read(p, merges[WRITE]),
(unsigned long long)part_stat_read(p, sectors[WRITE]),
jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
p->in_flight,
jiffies_to_msecs(part_stat_read(p, io_ticks)),
jiffies_to_msecs(part_stat_read(p, time_in_queue)));
}
#ifdef CONFIG_FAIL_MAKE_REQUEST
ssize_t part_fail_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%d\n", p->make_it_fail);
}
ssize_t part_fail_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct hd_struct *p = dev_to_part(dev);
int i;
if (count > 0 && sscanf(buf, "%d", &i) > 0)
p->make_it_fail = (i == 0) ? 0 : 1;
return count;
}
#endif
static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
#endif
static struct attribute *part_attrs[] = {
&dev_attr_partition.attr,
&dev_attr_start.attr,
&dev_attr_size.attr,
&dev_attr_stat.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
#endif
NULL
};
static struct attribute_group part_attr_group = {
.attrs = part_attrs,
};
static struct attribute_group *part_attr_groups[] = {
&part_attr_group,
NULL
};
static void part_release(struct device *dev)
{
struct hd_struct *p = dev_to_part(dev);
free_part_stats(p);
kfree(p);
}
struct device_type part_type = {
.name = "partition",
.groups = part_attr_groups,
.release = part_release,
};
static void delete_partition_rcu_cb(struct rcu_head *head)
{
struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
part->start_sect = 0;
part->nr_sects = 0;
part_stat_set_all(part, 0);
put_device(part_to_dev(part));
}
void delete_partition(struct gendisk *disk, int partno)
{
struct disk_part_tbl *ptbl = disk->part_tbl;
struct hd_struct *part;
if (partno >= ptbl->len)
return;
part = ptbl->part[partno];
if (!part)
return;
blk_free_devt(part_devt(part));
rcu_assign_pointer(ptbl->part[partno], NULL);
kobject_put(part->holder_dir);
device_del(part_to_dev(part));
call_rcu(&part->rcu_head, delete_partition_rcu_cb);
}
static ssize_t whole_disk_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return 0;
}
static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
whole_disk_show, NULL);
int add_partition(struct gendisk *disk, int partno,
sector_t start, sector_t len, int flags)
{
struct hd_struct *p;
dev_t devt = MKDEV(0, 0);
struct device *ddev = disk_to_dev(disk);
struct device *pdev;
struct disk_part_tbl *ptbl;
const char *dname;
int err;
err = disk_expand_part_tbl(disk, partno);
if (err)
return err;
ptbl = disk->part_tbl;
if (ptbl->part[partno])
return -EBUSY;
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
if (!init_part_stats(p)) {
err = -ENOMEM;
goto out_free;
}
pdev = part_to_dev(p);
p->start_sect = start;
p->nr_sects = len;
p->partno = partno;
p->policy = get_disk_ro(disk);
dname = dev_name(ddev);
if (isdigit(dname[strlen(dname) - 1]))
snprintf(pdev->bus_id, BUS_ID_SIZE, "%sp%d", dname, partno);
else
snprintf(pdev->bus_id, BUS_ID_SIZE, "%s%d", dname, partno);
device_initialize(pdev);
pdev->class = &block_class;
pdev->type = &part_type;
pdev->parent = ddev;
err = blk_alloc_devt(p, &devt);
if (err)
goto out_free;
pdev->devt = devt;
/* delay uevent until 'holders' subdir is created */
pdev->uevent_suppress = 1;
err = device_add(pdev);
if (err)
goto out_put;
err = -ENOMEM;
p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
if (!p->holder_dir)
goto out_del;
pdev->uevent_suppress = 0;
if (flags & ADDPART_FLAG_WHOLEDISK) {
err = device_create_file(pdev, &dev_attr_whole_disk);
if (err)
goto out_del;
}
/* everything is up and running, commence */
INIT_RCU_HEAD(&p->rcu_head);
rcu_assign_pointer(ptbl->part[partno], p);
/* suppress uevent if the disk supresses it */
if (!ddev->uevent_suppress)
kobject_uevent(&pdev->kobj, KOBJ_ADD);
return 0;
out_free:
kfree(p);
return err;
out_del:
kobject_put(p->holder_dir);
device_del(pdev);
out_put:
put_device(pdev);
blk_free_devt(devt);
return err;
}
/* Not exported, helper to add_disk(). */
void register_disk(struct gendisk *disk)
{
struct device *ddev = disk_to_dev(disk);
struct block_device *bdev;
struct disk_part_iter piter;
struct hd_struct *part;
char *s;
int err;
ddev->parent = disk->driverfs_dev;
strlcpy(ddev->bus_id, disk->disk_name, BUS_ID_SIZE);
/* ewww... some of these buggers have / in the name... */
s = strchr(ddev->bus_id, '/');
if (s)
*s = '!';
/* delay uevents, until we scanned partition table */
ddev->uevent_suppress = 1;
if (device_add(ddev))
return;
#ifndef CONFIG_SYSFS_DEPRECATED
err = sysfs_create_link(block_depr, &ddev->kobj,
kobject_name(&ddev->kobj));
if (err) {
device_del(ddev);
return;
}
#endif
disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
/* No minors to use for partitions */
if (!disk_partitionable(disk))
goto exit;
/* No such device (e.g., media were just removed) */
if (!get_capacity(disk))
goto exit;
bdev = bdget_disk(disk, 0);
if (!bdev)
goto exit;
bdev->bd_invalidated = 1;
err = blkdev_get(bdev, FMODE_READ, 0);
if (err < 0)
goto exit;
blkdev_put(bdev);
exit:
/* announce disk after possible partitions are created */
ddev->uevent_suppress = 0;
kobject_uevent(&ddev->kobj, KOBJ_ADD);
/* announce possible partitions */
disk_part_iter_init(&piter, disk, 0);
while ((part = disk_part_iter_next(&piter)))
kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
disk_part_iter_exit(&piter);
}
int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
{
struct disk_part_iter piter;
struct hd_struct *part;
struct parsed_partitions *state;
int p, highest, res;
if (bdev->bd_part_count)
return -EBUSY;
res = invalidate_partition(disk, 0);
if (res)
return res;
disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
while ((part = disk_part_iter_next(&piter)))
delete_partition(disk, part->partno);
disk_part_iter_exit(&piter);
if (disk->fops->revalidate_disk)
disk->fops->revalidate_disk(disk);
check_disk_size_change(disk, bdev);
bdev->bd_invalidated = 0;
if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
return 0;
if (IS_ERR(state)) /* I/O error reading the partition table */
return -EIO;
/* tell userspace that the media / partition table may have changed */
kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
/* Detect the highest partition number and preallocate
* disk->part_tbl. This is an optimization and not strictly
* necessary.
*/
for (p = 1, highest = 0; p < state->limit; p++)
if (state->parts[p].size)
highest = p;
disk_expand_part_tbl(disk, highest);
/* add partitions */
for (p = 1; p < state->limit; p++) {
sector_t size = state->parts[p].size;
sector_t from = state->parts[p].from;
if (!size)
continue;
if (from >= get_capacity(disk)) {
printk(KERN_WARNING
"%s: p%d ignored, start %llu is behind the end of the disk\n",
disk->disk_name, p, (unsigned long long) from);
continue;
}
if (from + size > get_capacity(disk)) {
/*
* we can not ignore partitions of broken tables
* created by for example camera firmware, but we
* limit them to the end of the disk to avoid
* creating invalid block devices
*/
printk(KERN_WARNING
"%s: p%d size %llu limited to end of disk\n",
disk->disk_name, p, (unsigned long long) size);
size = get_capacity(disk) - from;
}
res = add_partition(disk, p, from, size, state->parts[p].flags);
if (res) {
printk(KERN_ERR " %s: p%d could not be added: %d\n",
disk->disk_name, p, -res);
continue;
}
#ifdef CONFIG_BLK_DEV_MD
if (state->parts[p].flags & ADDPART_FLAG_RAID)
md_autodetect_dev(bdev->bd_dev+p);
#endif
}
kfree(state);
return 0;
}
unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
{
struct address_space *mapping = bdev->bd_inode->i_mapping;
struct page *page;
page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
NULL);
if (!IS_ERR(page)) {
if (PageError(page))
goto fail;
p->v = page;
return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
fail:
page_cache_release(page);
}
p->v = NULL;
return NULL;
}
EXPORT_SYMBOL(read_dev_sector);
void del_gendisk(struct gendisk *disk)
{
struct disk_part_iter piter;
struct hd_struct *part;
/* invalidate stuff */
disk_part_iter_init(&piter, disk,
DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
while ((part = disk_part_iter_next(&piter))) {
invalidate_partition(disk, part->partno);
delete_partition(disk, part->partno);
}
disk_part_iter_exit(&piter);
invalidate_partition(disk, 0);
blk_free_devt(disk_to_dev(disk)->devt);
set_capacity(disk, 0);
disk->flags &= ~GENHD_FL_UP;
unlink_gendisk(disk);
part_stat_set_all(&disk->part0, 0);
disk->part0.stamp = 0;
kobject_put(disk->part0.holder_dir);
kobject_put(disk->slave_dir);
disk->driverfs_dev = NULL;
#ifndef CONFIG_SYSFS_DEPRECATED
sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
#endif
device_del(disk_to_dev(disk));
}