linux/block/genhd.c
Peter Zijlstra cf0ca9fe5d mm: bdi: export BDI attributes in sysfs
Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object.
This allows us to see and set the various BDI specific variables.

In particular this properly exposes the read-ahead window for all relevant
users and /sys/block/<block>/queue/read_ahead_kb should be deprecated.

With patient help from Kay Sievers and Greg KH

[mszeredi@suse.cz]

 - split off NFS and FUSE changes into separate patches
 - document new sysfs attributes under Documentation/ABI
 - do bdi_class_init as a core_initcall, otherwise the "default" BDI
   won't be initialized
 - remove bdi_init_fmt macro, it's not used very much

[akpm@linux-foundation.org: fix ia64 warning]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Greg KH <greg@kroah.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:49 -07:00

788 lines
18 KiB
C

/*
* gendisk handling
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/kobj_map.h>
#include <linux/buffer_head.h>
#include <linux/mutex.h>
#include "blk.h"
static DEFINE_MUTEX(block_class_lock);
#ifndef CONFIG_SYSFS_DEPRECATED
struct kobject *block_depr;
#endif
static struct device_type disk_type;
/*
* Can be deleted altogether. Later.
*
*/
static struct blk_major_name {
struct blk_major_name *next;
int major;
char name[16];
} *major_names[BLKDEV_MAJOR_HASH_SIZE];
/* index in the above - for now: assume no multimajor ranges */
static inline int major_to_index(int major)
{
return major % BLKDEV_MAJOR_HASH_SIZE;
}
#ifdef CONFIG_PROC_FS
void blkdev_show(struct seq_file *f, off_t offset)
{
struct blk_major_name *dp;
if (offset < BLKDEV_MAJOR_HASH_SIZE) {
mutex_lock(&block_class_lock);
for (dp = major_names[offset]; dp; dp = dp->next)
seq_printf(f, "%3d %s\n", dp->major, dp->name);
mutex_unlock(&block_class_lock);
}
}
#endif /* CONFIG_PROC_FS */
int register_blkdev(unsigned int major, const char *name)
{
struct blk_major_name **n, *p;
int index, ret = 0;
mutex_lock(&block_class_lock);
/* temporary */
if (major == 0) {
for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
if (major_names[index] == NULL)
break;
}
if (index == 0) {
printk("register_blkdev: failed to get major for %s\n",
name);
ret = -EBUSY;
goto out;
}
major = index;
ret = major;
}
p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
if (p == NULL) {
ret = -ENOMEM;
goto out;
}
p->major = major;
strlcpy(p->name, name, sizeof(p->name));
p->next = NULL;
index = major_to_index(major);
for (n = &major_names[index]; *n; n = &(*n)->next) {
if ((*n)->major == major)
break;
}
if (!*n)
*n = p;
else
ret = -EBUSY;
if (ret < 0) {
printk("register_blkdev: cannot get major %d for %s\n",
major, name);
kfree(p);
}
out:
mutex_unlock(&block_class_lock);
return ret;
}
EXPORT_SYMBOL(register_blkdev);
void unregister_blkdev(unsigned int major, const char *name)
{
struct blk_major_name **n;
struct blk_major_name *p = NULL;
int index = major_to_index(major);
mutex_lock(&block_class_lock);
for (n = &major_names[index]; *n; n = &(*n)->next)
if ((*n)->major == major)
break;
if (!*n || strcmp((*n)->name, name)) {
WARN_ON(1);
} else {
p = *n;
*n = p->next;
}
mutex_unlock(&block_class_lock);
kfree(p);
}
EXPORT_SYMBOL(unregister_blkdev);
static struct kobj_map *bdev_map;
/*
* Register device numbers dev..(dev+range-1)
* range must be nonzero
* The hash chain is sorted on range, so that subranges can override.
*/
void blk_register_region(dev_t devt, unsigned long range, struct module *module,
struct kobject *(*probe)(dev_t, int *, void *),
int (*lock)(dev_t, void *), void *data)
{
kobj_map(bdev_map, devt, range, module, probe, lock, data);
}
EXPORT_SYMBOL(blk_register_region);
void blk_unregister_region(dev_t devt, unsigned long range)
{
kobj_unmap(bdev_map, devt, range);
}
EXPORT_SYMBOL(blk_unregister_region);
static struct kobject *exact_match(dev_t devt, int *part, void *data)
{
struct gendisk *p = data;
return &p->dev.kobj;
}
static int exact_lock(dev_t devt, void *data)
{
struct gendisk *p = data;
if (!get_disk(p))
return -1;
return 0;
}
/**
* add_disk - add partitioning information to kernel list
* @disk: per-device partitioning information
*
* This function registers the partitioning information in @disk
* with the kernel.
*/
void add_disk(struct gendisk *disk)
{
struct backing_dev_info *bdi;
disk->flags |= GENHD_FL_UP;
blk_register_region(MKDEV(disk->major, disk->first_minor),
disk->minors, NULL, exact_match, exact_lock, disk);
register_disk(disk);
blk_register_queue(disk);
bdi = &disk->queue->backing_dev_info;
bdi_register_dev(bdi, MKDEV(disk->major, disk->first_minor));
sysfs_create_link(&disk->dev.kobj, &bdi->dev->kobj, "bdi");
}
EXPORT_SYMBOL(add_disk);
EXPORT_SYMBOL(del_gendisk); /* in partitions/check.c */
void unlink_gendisk(struct gendisk *disk)
{
sysfs_remove_link(&disk->dev.kobj, "bdi");
bdi_unregister(&disk->queue->backing_dev_info);
blk_unregister_queue(disk);
blk_unregister_region(MKDEV(disk->major, disk->first_minor),
disk->minors);
}
/**
* get_gendisk - get partitioning information for a given device
* @dev: device to get partitioning information for
*
* This function gets the structure containing partitioning
* information for the given device @dev.
*/
struct gendisk *get_gendisk(dev_t devt, int *part)
{
struct kobject *kobj = kobj_lookup(bdev_map, devt, part);
struct device *dev = kobj_to_dev(kobj);
return kobj ? dev_to_disk(dev) : NULL;
}
/*
* print a full list of all partitions - intended for places where the root
* filesystem can't be mounted and thus to give the victim some idea of what
* went wrong
*/
void __init printk_all_partitions(void)
{
struct device *dev;
struct gendisk *sgp;
char buf[BDEVNAME_SIZE];
int n;
mutex_lock(&block_class_lock);
/* For each block device... */
list_for_each_entry(dev, &block_class.devices, node) {
if (dev->type != &disk_type)
continue;
sgp = dev_to_disk(dev);
/*
* Don't show empty devices or things that have been surpressed
*/
if (get_capacity(sgp) == 0 ||
(sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
continue;
/*
* Note, unlike /proc/partitions, I am showing the numbers in
* hex - the same format as the root= option takes.
*/
printk("%02x%02x %10llu %s",
sgp->major, sgp->first_minor,
(unsigned long long)get_capacity(sgp) >> 1,
disk_name(sgp, 0, buf));
if (sgp->driverfs_dev != NULL &&
sgp->driverfs_dev->driver != NULL)
printk(" driver: %s\n",
sgp->driverfs_dev->driver->name);
else
printk(" (driver?)\n");
/* now show the partitions */
for (n = 0; n < sgp->minors - 1; ++n) {
if (sgp->part[n] == NULL)
continue;
if (sgp->part[n]->nr_sects == 0)
continue;
printk(" %02x%02x %10llu %s\n",
sgp->major, n + 1 + sgp->first_minor,
(unsigned long long)sgp->part[n]->nr_sects >> 1,
disk_name(sgp, n + 1, buf));
}
}
mutex_unlock(&block_class_lock);
}
#ifdef CONFIG_PROC_FS
/* iterator */
static void *part_start(struct seq_file *part, loff_t *pos)
{
loff_t k = *pos;
struct device *dev;
mutex_lock(&block_class_lock);
list_for_each_entry(dev, &block_class.devices, node) {
if (dev->type != &disk_type)
continue;
if (!k--)
return dev_to_disk(dev);
}
return NULL;
}
static void *part_next(struct seq_file *part, void *v, loff_t *pos)
{
struct gendisk *gp = v;
struct device *dev;
++*pos;
list_for_each_entry(dev, &gp->dev.node, node) {
if (&dev->node == &block_class.devices)
return NULL;
if (dev->type == &disk_type)
return dev_to_disk(dev);
}
return NULL;
}
static void part_stop(struct seq_file *part, void *v)
{
mutex_unlock(&block_class_lock);
}
static int show_partition(struct seq_file *part, void *v)
{
struct gendisk *sgp = v;
int n;
char buf[BDEVNAME_SIZE];
if (&sgp->dev.node == block_class.devices.next)
seq_puts(part, "major minor #blocks name\n\n");
/* Don't show non-partitionable removeable devices or empty devices */
if (!get_capacity(sgp) ||
(sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
return 0;
if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
return 0;
/* show the full disk and all non-0 size partitions of it */
seq_printf(part, "%4d %4d %10llu %s\n",
sgp->major, sgp->first_minor,
(unsigned long long)get_capacity(sgp) >> 1,
disk_name(sgp, 0, buf));
for (n = 0; n < sgp->minors - 1; n++) {
if (!sgp->part[n])
continue;
if (sgp->part[n]->nr_sects == 0)
continue;
seq_printf(part, "%4d %4d %10llu %s\n",
sgp->major, n + 1 + sgp->first_minor,
(unsigned long long)sgp->part[n]->nr_sects >> 1 ,
disk_name(sgp, n + 1, buf));
}
return 0;
}
const struct seq_operations partitions_op = {
.start = part_start,
.next = part_next,
.stop = part_stop,
.show = show_partition
};
#endif
static struct kobject *base_probe(dev_t devt, int *part, void *data)
{
if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
/* Make old-style 2.4 aliases work */
request_module("block-major-%d", MAJOR(devt));
return NULL;
}
static int __init genhd_device_init(void)
{
int error = class_register(&block_class);
if (unlikely(error))
return error;
bdev_map = kobj_map_init(base_probe, &block_class_lock);
blk_dev_init();
#ifndef CONFIG_SYSFS_DEPRECATED
/* create top-level block dir */
block_depr = kobject_create_and_add("block", NULL);
#endif
return 0;
}
subsys_initcall(genhd_device_init);
static ssize_t disk_range_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", disk->minors);
}
static ssize_t disk_removable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n",
(disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
}
static ssize_t disk_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%llu\n", (unsigned long long)get_capacity(disk));
}
static ssize_t disk_capability_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%x\n", disk->flags);
}
static ssize_t disk_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
preempt_disable();
disk_round_stats(disk);
preempt_enable();
return sprintf(buf,
"%8lu %8lu %8llu %8u "
"%8lu %8lu %8llu %8u "
"%8u %8u %8u"
"\n",
disk_stat_read(disk, ios[READ]),
disk_stat_read(disk, merges[READ]),
(unsigned long long)disk_stat_read(disk, sectors[READ]),
jiffies_to_msecs(disk_stat_read(disk, ticks[READ])),
disk_stat_read(disk, ios[WRITE]),
disk_stat_read(disk, merges[WRITE]),
(unsigned long long)disk_stat_read(disk, sectors[WRITE]),
jiffies_to_msecs(disk_stat_read(disk, ticks[WRITE])),
disk->in_flight,
jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
}
#ifdef CONFIG_FAIL_MAKE_REQUEST
static ssize_t disk_fail_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", disk->flags & GENHD_FL_FAIL ? 1 : 0);
}
static ssize_t disk_fail_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct gendisk *disk = dev_to_disk(dev);
int i;
if (count > 0 && sscanf(buf, "%d", &i) > 0) {
if (i == 0)
disk->flags &= ~GENHD_FL_FAIL;
else
disk->flags |= GENHD_FL_FAIL;
}
return count;
}
#endif
static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, disk_size_show, NULL);
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, disk_stat_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, S_IRUGO|S_IWUSR, disk_fail_show, disk_fail_store);
#endif
static struct attribute *disk_attrs[] = {
&dev_attr_range.attr,
&dev_attr_removable.attr,
&dev_attr_size.attr,
&dev_attr_capability.attr,
&dev_attr_stat.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
#endif
NULL
};
static struct attribute_group disk_attr_group = {
.attrs = disk_attrs,
};
static struct attribute_group *disk_attr_groups[] = {
&disk_attr_group,
NULL
};
static void disk_release(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
kfree(disk->random);
kfree(disk->part);
free_disk_stats(disk);
kfree(disk);
}
struct class block_class = {
.name = "block",
};
static struct device_type disk_type = {
.name = "disk",
.groups = disk_attr_groups,
.release = disk_release,
};
/*
* aggregate disk stat collector. Uses the same stats that the sysfs
* entries do, above, but makes them available through one seq_file.
*
* The output looks suspiciously like /proc/partitions with a bunch of
* extra fields.
*/
static void *diskstats_start(struct seq_file *part, loff_t *pos)
{
loff_t k = *pos;
struct device *dev;
mutex_lock(&block_class_lock);
list_for_each_entry(dev, &block_class.devices, node) {
if (dev->type != &disk_type)
continue;
if (!k--)
return dev_to_disk(dev);
}
return NULL;
}
static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
{
struct gendisk *gp = v;
struct device *dev;
++*pos;
list_for_each_entry(dev, &gp->dev.node, node) {
if (&dev->node == &block_class.devices)
return NULL;
if (dev->type == &disk_type)
return dev_to_disk(dev);
}
return NULL;
}
static void diskstats_stop(struct seq_file *part, void *v)
{
mutex_unlock(&block_class_lock);
}
static int diskstats_show(struct seq_file *s, void *v)
{
struct gendisk *gp = v;
char buf[BDEVNAME_SIZE];
int n = 0;
/*
if (&gp->dev.kobj.entry == block_class.devices.next)
seq_puts(s, "major minor name"
" rio rmerge rsect ruse wio wmerge "
"wsect wuse running use aveq"
"\n\n");
*/
preempt_disable();
disk_round_stats(gp);
preempt_enable();
seq_printf(s, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
gp->major, n + gp->first_minor, disk_name(gp, n, buf),
disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
(unsigned long long)disk_stat_read(gp, sectors[0]),
jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
(unsigned long long)disk_stat_read(gp, sectors[1]),
jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
gp->in_flight,
jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
/* now show all non-0 size partitions of it */
for (n = 0; n < gp->minors - 1; n++) {
struct hd_struct *hd = gp->part[n];
if (!hd || !hd->nr_sects)
continue;
preempt_disable();
part_round_stats(hd);
preempt_enable();
seq_printf(s, "%4d %4d %s %lu %lu %llu "
"%u %lu %lu %llu %u %u %u %u\n",
gp->major, n + gp->first_minor + 1,
disk_name(gp, n + 1, buf),
part_stat_read(hd, ios[0]),
part_stat_read(hd, merges[0]),
(unsigned long long)part_stat_read(hd, sectors[0]),
jiffies_to_msecs(part_stat_read(hd, ticks[0])),
part_stat_read(hd, ios[1]),
part_stat_read(hd, merges[1]),
(unsigned long long)part_stat_read(hd, sectors[1]),
jiffies_to_msecs(part_stat_read(hd, ticks[1])),
hd->in_flight,
jiffies_to_msecs(part_stat_read(hd, io_ticks)),
jiffies_to_msecs(part_stat_read(hd, time_in_queue))
);
}
return 0;
}
const struct seq_operations diskstats_op = {
.start = diskstats_start,
.next = diskstats_next,
.stop = diskstats_stop,
.show = diskstats_show
};
static void media_change_notify_thread(struct work_struct *work)
{
struct gendisk *gd = container_of(work, struct gendisk, async_notify);
char event[] = "MEDIA_CHANGE=1";
char *envp[] = { event, NULL };
/*
* set enviroment vars to indicate which event this is for
* so that user space will know to go check the media status.
*/
kobject_uevent_env(&gd->dev.kobj, KOBJ_CHANGE, envp);
put_device(gd->driverfs_dev);
}
#if 0
void genhd_media_change_notify(struct gendisk *disk)
{
get_device(disk->driverfs_dev);
schedule_work(&disk->async_notify);
}
EXPORT_SYMBOL_GPL(genhd_media_change_notify);
#endif /* 0 */
dev_t blk_lookup_devt(const char *name)
{
struct device *dev;
dev_t devt = MKDEV(0, 0);
mutex_lock(&block_class_lock);
list_for_each_entry(dev, &block_class.devices, node) {
if (strcmp(dev->bus_id, name) == 0) {
devt = dev->devt;
break;
}
}
mutex_unlock(&block_class_lock);
return devt;
}
EXPORT_SYMBOL(blk_lookup_devt);
struct gendisk *alloc_disk(int minors)
{
return alloc_disk_node(minors, -1);
}
struct gendisk *alloc_disk_node(int minors, int node_id)
{
struct gendisk *disk;
disk = kmalloc_node(sizeof(struct gendisk),
GFP_KERNEL | __GFP_ZERO, node_id);
if (disk) {
if (!init_disk_stats(disk)) {
kfree(disk);
return NULL;
}
if (minors > 1) {
int size = (minors - 1) * sizeof(struct hd_struct *);
disk->part = kmalloc_node(size,
GFP_KERNEL | __GFP_ZERO, node_id);
if (!disk->part) {
free_disk_stats(disk);
kfree(disk);
return NULL;
}
}
disk->minors = minors;
rand_initialize_disk(disk);
disk->dev.class = &block_class;
disk->dev.type = &disk_type;
device_initialize(&disk->dev);
INIT_WORK(&disk->async_notify,
media_change_notify_thread);
}
return disk;
}
EXPORT_SYMBOL(alloc_disk);
EXPORT_SYMBOL(alloc_disk_node);
struct kobject *get_disk(struct gendisk *disk)
{
struct module *owner;
struct kobject *kobj;
if (!disk->fops)
return NULL;
owner = disk->fops->owner;
if (owner && !try_module_get(owner))
return NULL;
kobj = kobject_get(&disk->dev.kobj);
if (kobj == NULL) {
module_put(owner);
return NULL;
}
return kobj;
}
EXPORT_SYMBOL(get_disk);
void put_disk(struct gendisk *disk)
{
if (disk)
kobject_put(&disk->dev.kobj);
}
EXPORT_SYMBOL(put_disk);
void set_device_ro(struct block_device *bdev, int flag)
{
if (bdev->bd_contains != bdev)
bdev->bd_part->policy = flag;
else
bdev->bd_disk->policy = flag;
}
EXPORT_SYMBOL(set_device_ro);
void set_disk_ro(struct gendisk *disk, int flag)
{
int i;
disk->policy = flag;
for (i = 0; i < disk->minors - 1; i++)
if (disk->part[i]) disk->part[i]->policy = flag;
}
EXPORT_SYMBOL(set_disk_ro);
int bdev_read_only(struct block_device *bdev)
{
if (!bdev)
return 0;
else if (bdev->bd_contains != bdev)
return bdev->bd_part->policy;
else
return bdev->bd_disk->policy;
}
EXPORT_SYMBOL(bdev_read_only);
int invalidate_partition(struct gendisk *disk, int index)
{
int res = 0;
struct block_device *bdev = bdget_disk(disk, index);
if (bdev) {
fsync_bdev(bdev);
res = __invalidate_device(bdev);
bdput(bdev);
}
return res;
}
EXPORT_SYMBOL(invalidate_partition);