forked from Minki/linux
dm: allow active and inactive tables to share dm_devs
Until this change, when loading a new DM table, DM core would re-open all of the devices in the DM table. Now, DM core will avoid redundant device opens (and closes when destroying the old table) if the old table already has a device open using the same mode. This is achieved by managing reference counts on the table_devices that DM core now stores in the mapped_device structure (rather than in the dm_table structure). So a mapped_device's active and inactive dm_tables' dm_dev lists now just point to the dm_devs stored in the mapped_device's table_devices list. This improvement in DM core's device reference counting has the side-effect of fixing a long-standing limitation of the multipath target: a DM multipath table couldn't include any paths that were unusable (failed). For example: if all paths have failed and you add a new, working, path to the table; you can't use it since the table load would fail due to it still containing failed paths. Now a re-load of a multipath table can include failed devices and when those devices become active again they can be used instantly. The device list code in dm.c isn't a straight copy/paste from the code in dm-table.c, but it's very close (aside from some variable renames). One subtle difference is that find_table_device for the tables_devices list will only match devices with the same name and mode. This is because we don't want to upgrade a device's mode in the active table when an inactive table is loaded. Access to the mapped_device structure's tables_devices list requires a mutex (tables_devices_lock), so that tables cannot be created and destroyed concurrently. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Benjamin Marzinski
Mike Snitzer
parent
1f27197247
commit
86f1152b11
@ -1418,7 +1418,7 @@ static void retrieve_deps(struct dm_table *table,
|
||||
deps->count = count;
|
||||
count = 0;
|
||||
list_for_each_entry (dd, dm_table_get_devices(table), list)
|
||||
deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
|
||||
deps->dev[count++] = huge_encode_dev(dd->dm_dev->bdev->bd_dev);
|
||||
|
||||
param->data_size = param->data_start + needed;
|
||||
}
|
||||
|
||||
@ -210,15 +210,16 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void free_devices(struct list_head *devices)
|
||||
static void free_devices(struct list_head *devices, struct mapped_device *md)
|
||||
{
|
||||
struct list_head *tmp, *next;
|
||||
|
||||
list_for_each_safe(tmp, next, devices) {
|
||||
struct dm_dev_internal *dd =
|
||||
list_entry(tmp, struct dm_dev_internal, list);
|
||||
DMWARN("dm_table_destroy: dm_put_device call missing for %s",
|
||||
dd->dm_dev.name);
|
||||
DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
|
||||
dm_device_name(md), dd->dm_dev->name);
|
||||
dm_put_table_device(md, dd->dm_dev);
|
||||
kfree(dd);
|
||||
}
|
||||
}
|
||||
@ -247,7 +248,7 @@ void dm_table_destroy(struct dm_table *t)
|
||||
vfree(t->highs);
|
||||
|
||||
/* free the device list */
|
||||
free_devices(&t->devices);
|
||||
free_devices(&t->devices, t->md);
|
||||
|
||||
dm_free_md_mempools(t->mempools);
|
||||
|
||||
@ -262,52 +263,12 @@ static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
|
||||
struct dm_dev_internal *dd;
|
||||
|
||||
list_for_each_entry (dd, l, list)
|
||||
if (dd->dm_dev.bdev->bd_dev == dev)
|
||||
if (dd->dm_dev->bdev->bd_dev == dev)
|
||||
return dd;
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/*
|
||||
* Open a device so we can use it as a map destination.
|
||||
*/
|
||||
static int open_dev(struct dm_dev_internal *d, dev_t dev,
|
||||
struct mapped_device *md)
|
||||
{
|
||||
static char *_claim_ptr = "I belong to device-mapper";
|
||||
struct block_device *bdev;
|
||||
|
||||
int r;
|
||||
|
||||
BUG_ON(d->dm_dev.bdev);
|
||||
|
||||
bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);
|
||||
if (IS_ERR(bdev))
|
||||
return PTR_ERR(bdev);
|
||||
|
||||
r = bd_link_disk_holder(bdev, dm_disk(md));
|
||||
if (r) {
|
||||
blkdev_put(bdev, d->dm_dev.mode | FMODE_EXCL);
|
||||
return r;
|
||||
}
|
||||
|
||||
d->dm_dev.bdev = bdev;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Close a device that we've been using.
|
||||
*/
|
||||
static void close_dev(struct dm_dev_internal *d, struct mapped_device *md)
|
||||
{
|
||||
if (!d->dm_dev.bdev)
|
||||
return;
|
||||
|
||||
bd_unlink_disk_holder(d->dm_dev.bdev, dm_disk(md));
|
||||
blkdev_put(d->dm_dev.bdev, d->dm_dev.mode | FMODE_EXCL);
|
||||
d->dm_dev.bdev = NULL;
|
||||
}
|
||||
|
||||
/*
|
||||
* If possible, this checks an area of a destination device is invalid.
|
||||
*/
|
||||
@ -386,19 +347,17 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
|
||||
struct mapped_device *md)
|
||||
{
|
||||
int r;
|
||||
struct dm_dev_internal dd_new, dd_old;
|
||||
struct dm_dev *old_dev, *new_dev;
|
||||
|
||||
dd_new = dd_old = *dd;
|
||||
old_dev = dd->dm_dev;
|
||||
|
||||
dd_new.dm_dev.mode |= new_mode;
|
||||
dd_new.dm_dev.bdev = NULL;
|
||||
|
||||
r = open_dev(&dd_new, dd->dm_dev.bdev->bd_dev, md);
|
||||
r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
|
||||
dd->dm_dev->mode | new_mode, &new_dev);
|
||||
if (r)
|
||||
return r;
|
||||
|
||||
dd->dm_dev.mode |= new_mode;
|
||||
close_dev(&dd_old, md);
|
||||
dd->dm_dev = new_dev;
|
||||
dm_put_table_device(md, old_dev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
@ -440,27 +399,22 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
|
||||
if (!dd)
|
||||
return -ENOMEM;
|
||||
|
||||
dd->dm_dev.mode = mode;
|
||||
dd->dm_dev.bdev = NULL;
|
||||
|
||||
if ((r = open_dev(dd, dev, t->md))) {
|
||||
if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
|
||||
kfree(dd);
|
||||
return r;
|
||||
}
|
||||
|
||||
format_dev_t(dd->dm_dev.name, dev);
|
||||
|
||||
atomic_set(&dd->count, 0);
|
||||
list_add(&dd->list, &t->devices);
|
||||
|
||||
} else if (dd->dm_dev.mode != (mode | dd->dm_dev.mode)) {
|
||||
} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
|
||||
r = upgrade_mode(dd, mode, t->md);
|
||||
if (r)
|
||||
return r;
|
||||
}
|
||||
atomic_inc(&dd->count);
|
||||
|
||||
*result = &dd->dm_dev;
|
||||
*result = dd->dm_dev;
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(dm_get_device);
|
||||
@ -505,11 +459,23 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
|
||||
*/
|
||||
void dm_put_device(struct dm_target *ti, struct dm_dev *d)
|
||||
{
|
||||
struct dm_dev_internal *dd = container_of(d, struct dm_dev_internal,
|
||||
dm_dev);
|
||||
int found = 0;
|
||||
struct list_head *devices = &ti->table->devices;
|
||||
struct dm_dev_internal *dd;
|
||||
|
||||
list_for_each_entry(dd, devices, list) {
|
||||
if (dd->dm_dev == d) {
|
||||
found = 1;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (!found) {
|
||||
DMWARN("%s: device %s not in table devices list",
|
||||
dm_device_name(ti->table->md), d->name);
|
||||
return;
|
||||
}
|
||||
if (atomic_dec_and_test(&dd->count)) {
|
||||
close_dev(dd, ti->table->md);
|
||||
dm_put_table_device(ti->table->md, d);
|
||||
list_del(&dd->list);
|
||||
kfree(dd);
|
||||
}
|
||||
@ -906,7 +872,7 @@ static int dm_table_set_type(struct dm_table *t)
|
||||
/* Non-request-stackable devices can't be used for request-based dm */
|
||||
devices = dm_table_get_devices(t);
|
||||
list_for_each_entry(dd, devices, list) {
|
||||
if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev.bdev))) {
|
||||
if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev->bdev))) {
|
||||
DMWARN("table load rejected: including"
|
||||
" non-request-stackable devices");
|
||||
return -EINVAL;
|
||||
@ -1043,7 +1009,7 @@ static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
|
||||
struct gendisk *prev_disk = NULL, *template_disk = NULL;
|
||||
|
||||
list_for_each_entry(dd, devices, list) {
|
||||
template_disk = dd->dm_dev.bdev->bd_disk;
|
||||
template_disk = dd->dm_dev->bdev->bd_disk;
|
||||
if (!blk_get_integrity(template_disk))
|
||||
goto no_integrity;
|
||||
if (!match_all && !blk_integrity_is_initialized(template_disk))
|
||||
@ -1629,7 +1595,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
|
||||
int r = 0;
|
||||
|
||||
list_for_each_entry(dd, devices, list) {
|
||||
struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
|
||||
struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
|
||||
char b[BDEVNAME_SIZE];
|
||||
|
||||
if (likely(q))
|
||||
@ -1637,7 +1603,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
|
||||
else
|
||||
DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
|
||||
dm_device_name(t->md),
|
||||
bdevname(dd->dm_dev.bdev, b));
|
||||
bdevname(dd->dm_dev->bdev, b));
|
||||
}
|
||||
|
||||
list_for_each_entry(cb, &t->target_callbacks, list)
|
||||
|
||||
126
drivers/md/dm.c
126
drivers/md/dm.c
@ -142,6 +142,9 @@ struct mapped_device {
|
||||
*/
|
||||
struct dm_table *map;
|
||||
|
||||
struct list_head table_devices;
|
||||
struct mutex table_devices_lock;
|
||||
|
||||
unsigned long flags;
|
||||
|
||||
struct request_queue *queue;
|
||||
@ -212,6 +215,12 @@ struct dm_md_mempools {
|
||||
struct bio_set *bs;
|
||||
};
|
||||
|
||||
struct table_device {
|
||||
struct list_head list;
|
||||
atomic_t count;
|
||||
struct dm_dev dm_dev;
|
||||
};
|
||||
|
||||
#define RESERVED_BIO_BASED_IOS 16
|
||||
#define RESERVED_REQUEST_BASED_IOS 256
|
||||
#define RESERVED_MAX_IOS 1024
|
||||
@ -669,6 +678,120 @@ static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
|
||||
rcu_read_unlock();
|
||||
}
|
||||
|
||||
/*
|
||||
* Open a table device so we can use it as a map destination.
|
||||
*/
|
||||
static int open_table_device(struct table_device *td, dev_t dev,
|
||||
struct mapped_device *md)
|
||||
{
|
||||
static char *_claim_ptr = "I belong to device-mapper";
|
||||
struct block_device *bdev;
|
||||
|
||||
int r;
|
||||
|
||||
BUG_ON(td->dm_dev.bdev);
|
||||
|
||||
bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr);
|
||||
if (IS_ERR(bdev))
|
||||
return PTR_ERR(bdev);
|
||||
|
||||
r = bd_link_disk_holder(bdev, dm_disk(md));
|
||||
if (r) {
|
||||
blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
|
||||
return r;
|
||||
}
|
||||
|
||||
td->dm_dev.bdev = bdev;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Close a table device that we've been using.
|
||||
*/
|
||||
static void close_table_device(struct table_device *td, struct mapped_device *md)
|
||||
{
|
||||
if (!td->dm_dev.bdev)
|
||||
return;
|
||||
|
||||
bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
|
||||
blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
|
||||
td->dm_dev.bdev = NULL;
|
||||
}
|
||||
|
||||
static struct table_device *find_table_device(struct list_head *l, dev_t dev,
|
||||
fmode_t mode) {
|
||||
struct table_device *td;
|
||||
|
||||
list_for_each_entry(td, l, list)
|
||||
if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
|
||||
return td;
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
|
||||
struct dm_dev **result) {
|
||||
int r;
|
||||
struct table_device *td;
|
||||
|
||||
mutex_lock(&md->table_devices_lock);
|
||||
td = find_table_device(&md->table_devices, dev, mode);
|
||||
if (!td) {
|
||||
td = kmalloc(sizeof(*td), GFP_KERNEL);
|
||||
if (!td) {
|
||||
mutex_unlock(&md->table_devices_lock);
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
td->dm_dev.mode = mode;
|
||||
td->dm_dev.bdev = NULL;
|
||||
|
||||
if ((r = open_table_device(td, dev, md))) {
|
||||
mutex_unlock(&md->table_devices_lock);
|
||||
kfree(td);
|
||||
return r;
|
||||
}
|
||||
|
||||
format_dev_t(td->dm_dev.name, dev);
|
||||
|
||||
atomic_set(&td->count, 0);
|
||||
list_add(&td->list, &md->table_devices);
|
||||
}
|
||||
atomic_inc(&td->count);
|
||||
mutex_unlock(&md->table_devices_lock);
|
||||
|
||||
*result = &td->dm_dev;
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(dm_get_table_device);
|
||||
|
||||
void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
|
||||
{
|
||||
struct table_device *td = container_of(d, struct table_device, dm_dev);
|
||||
|
||||
mutex_lock(&md->table_devices_lock);
|
||||
if (atomic_dec_and_test(&td->count)) {
|
||||
close_table_device(td, md);
|
||||
list_del(&td->list);
|
||||
kfree(td);
|
||||
}
|
||||
mutex_unlock(&md->table_devices_lock);
|
||||
}
|
||||
EXPORT_SYMBOL(dm_put_table_device);
|
||||
|
||||
static void free_table_devices(struct list_head *devices)
|
||||
{
|
||||
struct list_head *tmp, *next;
|
||||
|
||||
list_for_each_safe(tmp, next, devices) {
|
||||
struct table_device *td = list_entry(tmp, struct table_device, list);
|
||||
|
||||
DMWARN("dm_destroy: %s still exists with %d references",
|
||||
td->dm_dev.name, atomic_read(&td->count));
|
||||
kfree(td);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Get the geometry associated with a dm device
|
||||
*/
|
||||
@ -1944,12 +2067,14 @@ static struct mapped_device *alloc_dev(int minor)
|
||||
md->type = DM_TYPE_NONE;
|
||||
mutex_init(&md->suspend_lock);
|
||||
mutex_init(&md->type_lock);
|
||||
mutex_init(&md->table_devices_lock);
|
||||
spin_lock_init(&md->deferred_lock);
|
||||
atomic_set(&md->holders, 1);
|
||||
atomic_set(&md->open_count, 0);
|
||||
atomic_set(&md->event_nr, 0);
|
||||
atomic_set(&md->uevent_seq, 0);
|
||||
INIT_LIST_HEAD(&md->uevent_list);
|
||||
INIT_LIST_HEAD(&md->table_devices);
|
||||
spin_lock_init(&md->uevent_lock);
|
||||
|
||||
md->queue = blk_alloc_queue(GFP_KERNEL);
|
||||
@ -2035,6 +2160,7 @@ static void free_dev(struct mapped_device *md)
|
||||
blk_integrity_unregister(md->disk);
|
||||
del_gendisk(md->disk);
|
||||
cleanup_srcu_struct(&md->io_barrier);
|
||||
free_table_devices(&md->table_devices);
|
||||
free_minor(minor);
|
||||
|
||||
spin_lock(&_minor_lock);
|
||||
|
||||
@ -44,7 +44,7 @@
|
||||
struct dm_dev_internal {
|
||||
struct list_head list;
|
||||
atomic_t count;
|
||||
struct dm_dev dm_dev;
|
||||
struct dm_dev *dm_dev;
|
||||
};
|
||||
|
||||
struct dm_table;
|
||||
@ -188,6 +188,9 @@ int dm_cancel_deferred_remove(struct mapped_device *md);
|
||||
int dm_request_based(struct mapped_device *md);
|
||||
sector_t dm_get_size(struct mapped_device *md);
|
||||
struct request_queue *dm_get_md_queue(struct mapped_device *md);
|
||||
int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
|
||||
struct dm_dev **result);
|
||||
void dm_put_table_device(struct mapped_device *md, struct dm_dev *d);
|
||||
struct dm_stats *dm_get_stats(struct mapped_device *md);
|
||||
|
||||
int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
|
||||
|
||||
@ -267,9 +267,9 @@ enum {
|
||||
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
|
||||
|
||||
#define DM_VERSION_MAJOR 4
|
||||
#define DM_VERSION_MINOR 27
|
||||
#define DM_VERSION_MINOR 28
|
||||
#define DM_VERSION_PATCHLEVEL 0
|
||||
#define DM_VERSION_EXTRA "-ioctl (2013-10-30)"
|
||||
#define DM_VERSION_EXTRA "-ioctl (2014-09-17)"
|
||||
|
||||
/* Status bits */
|
||||
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
|
||||
|
||||
Loading…
Reference in New Issue
Block a user