linux/block/genhd.c
Adel Gadllah 0b07de85a7 allow userspace to modify scsi command filter on per device basis
This patch exports the per-gendisk command filter to user space through
sysfs, so it can be changed by the system administrator.
All users of the old cmd filter have been converted to use the new one.

Original patch from Peter Jones.

Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03 13:21:14 +02:00

806 lines
19 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);
blk_register_filter(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)
{
blk_unregister_filter(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_ro_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%d\n", disk->policy ? 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(ro, S_IRUGO, disk_ro_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_ro.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, int part)
{
struct device *dev;
dev_t devt = MKDEV(0, 0);
mutex_lock(&block_class_lock);
list_for_each_entry(dev, &block_class.devices, node) {
if (dev->type != &disk_type)
continue;
if (strcmp(dev->bus_id, name) == 0) {
struct gendisk *disk = dev_to_disk(dev);
if (part < disk->minors)
devt = MKDEV(MAJOR(dev->devt),
MINOR(dev->devt) + part);
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);