int dm_resume(struct mapped_device *md)
{
struct bio *def;
struct dm_table *map = dm_get_table(md);
down_write(&md->lock);
if (!map ||
!test_bit(DMF_SUSPENDED, &md->flags) ||
!dm_table_get_size(map)) {
up_write(&md->lock);
dm_table_put(map);
return -EINVAL;
}
dm_table_resume_targets(map);
clear_bit(DMF_SUSPENDED, &md->flags);
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->lock);
__unlock_fs(md);
dm_table_unplug_all(map);
dm_table_put(map);
return 0;
}
static void dm_unplug_all(request_queue_t *q)
{
struct mapped_device *md = q->queuedata;
struct dm_table *map = dm_get_table(md);
if (map) {
dm_table_unplug_all(map);
dm_table_put(map);
}
}
/**ltl
* 功能: 映射设备的泄流处理函数
* 参数:
* 返回值:
* 说明:
*/
static void dm_unplug_all(request_queue_t *q)
{
struct mapped_device *md = q->queuedata;
struct dm_table *map = dm_get_table(md); /* 映射设备的映射表 */
if (map) {
dm_table_unplug_all(map); /* 将映射表中的所有物理设备泄流 */
dm_table_put(map);
}
}
int dm_resume(struct mapped_device *md)
{
int r = -EINVAL;
struct bio *def;
struct dm_table *map = NULL;
down(&md->suspend_lock);
if (!dm_suspended(md))
goto out;
map = dm_get_table(md);
if (!map || !dm_table_get_size(map))
goto out;
r = dm_table_resume_targets(map);
if (r)
goto out;
down_write(&md->io_lock);
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
unlock_fs(md);
if (md->suspended_bdev) {
bdput(md->suspended_bdev);
md->suspended_bdev = NULL;
}
clear_bit(DMF_SUSPENDED, &md->flags);
dm_table_unplug_all(map);
kobject_uevent(&md->disk->kobj, KOBJ_CHANGE);
r = 0;
out:
dm_table_put(map);
up(&md->suspend_lock);
return r;
}
/*
* We need to be able to change a mapping table under a mounted
* filesystem. For example we might want to move some data in
* the background. Before the table can be swapped with
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
int dm_suspend(struct mapped_device *md)
{
struct dm_table *map;
DECLARE_WAITQUEUE(wait, current);
/* Flush I/O to the device. */
down_read(&md->lock);
if (test_bit(DMF_BLOCK_IO, &md->flags)) {
up_read(&md->lock);
return -EINVAL;
}
__lock_fs(md);
up_read(&md->lock);
/*
* First we set the BLOCK_IO flag so no more ios will be
* mapped.
*/
down_write(&md->lock);
if (test_bit(DMF_BLOCK_IO, &md->flags)) {
/*
* If we get here we know another thread is
* trying to suspend as well, so we leave the fs
* locked for this thread.
*/
up_write(&md->lock);
return -EINVAL;
}
set_bit(DMF_BLOCK_IO, &md->flags);
add_wait_queue(&md->wait, &wait);
up_write(&md->lock);
/* unplug */
map = dm_get_table(md);
if (map) {
dm_table_unplug_all(map);
dm_table_put(map);
}
/*
* Then we wait for the already mapped ios to
* complete.
*/
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (!atomic_read(&md->pending) || signal_pending(current))
break;
io_schedule();
}
set_current_state(TASK_RUNNING);
down_write(&md->lock);
remove_wait_queue(&md->wait, &wait);
/* were we interrupted ? */
if (atomic_read(&md->pending)) {
__unlock_fs(md);
clear_bit(DMF_BLOCK_IO, &md->flags);
up_write(&md->lock);
return -EINTR;
}
set_bit(DMF_SUSPENDED, &md->flags);
map = dm_get_table(md);
if (map)
dm_table_suspend_targets(map);
dm_table_put(map);
up_write(&md->lock);
return 0;
}
/*
* We need to be able to change a mapping table under a mounted
* filesystem. For example we might want to move some data in
* the background. Before the table can be swapped with
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
struct bio *def;
int r = -EINVAL;
int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
down(&md->suspend_lock);
if (dm_suspended(md))
goto out_unlock;
map = dm_get_table(md);
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
* This flag is cleared before dm_suspend returns.
*/
if (noflush)
set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
/* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
/* bdget() can stall if the pending I/Os are not flushed */
if (!noflush) {
md->suspended_bdev = bdget_disk(md->disk, 0);
if (!md->suspended_bdev) {
DMWARN("bdget failed in dm_suspend");
r = -ENOMEM;
goto flush_and_out;
}
}
/*
* Flush I/O to the device.
* noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os.
*/
if (do_lockfs && !noflush) {
r = lock_fs(md);
if (r)
goto out;
}
/*
* First we set the BLOCK_IO flag so no more ios will be mapped.
*/
down_write(&md->io_lock);
set_bit(DMF_BLOCK_IO, &md->flags);
add_wait_queue(&md->wait, &wait);
up_write(&md->io_lock);
/* unplug */
if (map)
dm_table_unplug_all(map);
/*
* Then we wait for the already mapped ios to
* complete.
*/
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (!atomic_read(&md->pending) || signal_pending(current))
break;
io_schedule();
}
set_current_state(TASK_RUNNING);
down_write(&md->io_lock);
remove_wait_queue(&md->wait, &wait);
if (noflush) {
spin_lock_irqsave(&md->pushback_lock, flags);
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
bio_list_merge_head(&md->deferred, &md->pushback);
bio_list_init(&md->pushback);
spin_unlock_irqrestore(&md->pushback_lock, flags);
}
/* were we interrupted ? */
r = -EINTR;
if (atomic_read(&md->pending)) {
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
}
up_write(&md->io_lock);
dm_table_postsuspend_targets(map);
set_bit(DMF_SUSPENDED, &md->flags);
r = 0;
flush_and_out:
if (r && noflush) {
/*
* Because there may be already I/Os in the pushback list,
* flush them before return.
*/
down_write(&md->io_lock);
spin_lock_irqsave(&md->pushback_lock, flags);
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
bio_list_merge_head(&md->deferred, &md->pushback);
bio_list_init(&md->pushback);
spin_unlock_irqrestore(&md->pushback_lock, flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
}
out:
if (r && md->suspended_bdev) {
bdput(md->suspended_bdev);
md->suspended_bdev = NULL;
}
dm_table_put(map);
out_unlock:
up(&md->suspend_lock);
return r;
}
/*
* We need to be able to change a mapping table under a mounted
* filesystem. For example we might want to move some data in
* the background. Before the table can be swapped with
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
int dm_suspend(struct mapped_device *md, int do_lockfs)
{
struct dm_table *map = NULL;
DECLARE_WAITQUEUE(wait, current);
struct bio *def;
int r = -EINVAL;
down(&md->suspend_lock);
if (dm_suspended(md))
goto out;
map = dm_get_table(md);
/* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
md->suspended_bdev = bdget_disk(md->disk, 0);
if (!md->suspended_bdev) {
DMWARN("bdget failed in dm_suspend");
r = -ENOMEM;
goto out;
}
/* Flush I/O to the device. */
if (do_lockfs) {
r = lock_fs(md);
if (r)
goto out;
}
/*
* First we set the BLOCK_IO flag so no more ios will be mapped.
*/
down_write(&md->io_lock);
set_bit(DMF_BLOCK_IO, &md->flags);
add_wait_queue(&md->wait, &wait);
up_write(&md->io_lock);
/* unplug */
if (map)
dm_table_unplug_all(map);
/*
* Then we wait for the already mapped ios to
* complete.
*/
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (!atomic_read(&md->pending) || signal_pending(current))
break;
io_schedule();
}
set_current_state(TASK_RUNNING);
down_write(&md->io_lock);
remove_wait_queue(&md->wait, &wait);
/* were we interrupted ? */
r = -EINTR;
if (atomic_read(&md->pending)) {
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
unlock_fs(md);
goto out;
}
up_write(&md->io_lock);
dm_table_postsuspend_targets(map);
set_bit(DMF_SUSPENDED, &md->flags);
r = 0;
out:
if (r && md->suspended_bdev) {
bdput(md->suspended_bdev);
md->suspended_bdev = NULL;
}
dm_table_put(map);
up(&md->suspend_lock);
return r;
}
