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Commit cf222b37 authored by Alasdair G Kergon's avatar Alasdair G Kergon Committed by Linus Torvalds
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[PATCH] device-mapper: fix deadlocks in core (prep) 



Some code tidy-ups in preparation for the next patches.  Change
dm_table_pre/postsuspend_targets to accept NULL.  Use dm_suspended()
throughout.

Signed-Off-By: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8c56ac3f

drivers/md/dm-table.c

+6 −0
Original line number Diff line number Diff line
@@ -869,11 +869,17 @@ static void suspend_targets(struct dm_table *t, unsigned postsuspend) 


void dm_table_presuspend_targets(struct dm_table *t)

{

	if (!t)

		return;



	return suspend_targets(t, 0);

}



void dm_table_postsuspend_targets(struct dm_table *t)

{

	if (!t)

		return;



	return suspend_targets(t, 1);

}

drivers/md/dm.c

+33 −28
Original line number Diff line number Diff line
@@ -610,7 +610,7 @@ static int dm_flush_all(request_queue_t *q, struct gendisk *disk, 
	int ret = -ENXIO;



	if (map) {

		ret = dm_table_flush_all(md->map);

		ret = dm_table_flush_all(map);

		dm_table_put(map);

	}
@@ -854,7 +854,7 @@ static int __bind(struct mapped_device *md, struct dm_table *t) 
	write_unlock(&md->map_lock);



	dm_table_get(t);

	dm_table_event_callback(md->map, event_callback, md);

	dm_table_event_callback(t, event_callback, md);

	dm_table_set_restrictions(t, q);

	return 0;

}
@@ -935,7 +935,7 @@ void dm_put(struct mapped_device *md) 
	struct dm_table *map = dm_get_table(md);



	if (atomic_dec_and_test(&md->holders)) {

		if (!test_bit(DMF_SUSPENDED, &md->flags) && map) {

		if (!dm_suspended(md)) {

			dm_table_presuspend_targets(map);

			dm_table_postsuspend_targets(map);

		}
@@ -971,7 +971,7 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table) 
	down_write(&md->lock);



	/* device must be suspended */

	if (!test_bit(DMF_SUSPENDED, &md->flags))

	if (!dm_suspended(md))

		goto out;



	__unbind(md);
@@ -988,7 +988,7 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table) 
 */

static int __lock_fs(struct mapped_device *md)

{

	int error = -ENOMEM;

	int r = -ENOMEM;



	if (test_and_set_bit(DMF_FS_LOCKED, &md->flags))

		return 0;
@@ -1003,7 +1003,7 @@ static int __lock_fs(struct mapped_device *md) 


	md->frozen_sb = freeze_bdev(md->frozen_bdev);

	if (IS_ERR(md->frozen_sb)) {

		error = PTR_ERR(md->frozen_sb);

		r = PTR_ERR(md->frozen_sb);

		goto out_bdput;

	}
@@ -1019,7 +1019,7 @@ static int __lock_fs(struct mapped_device *md) 
	md->frozen_bdev = NULL;

out:

	clear_bit(DMF_FS_LOCKED, &md->flags);

	return error;

	return r;

}



static void __unlock_fs(struct mapped_device *md)
@@ -1045,20 +1045,20 @@ int dm_suspend(struct mapped_device *md) 
{

	struct dm_table *map;

	DECLARE_WAITQUEUE(wait, current);

	int error = -EINVAL;

	int r = -EINVAL;



	/* Flush I/O to the device. */

	down_read(&md->lock);

	if (test_bit(DMF_BLOCK_IO, &md->flags))

		goto out_read_unlock;



	map = dm_get_table(md);

	if (map)



	/* This does not get reverted if there's an error later. */

	dm_table_presuspend_targets(map);



	error = __lock_fs(md);

	if (error) {

	/* Flush I/O to the device. */

	r = __lock_fs(md);

	if (r) {

		dm_table_put(map);

		goto out_read_unlock;

	}
@@ -1071,7 +1071,7 @@ int dm_suspend(struct mapped_device *md) 
	 * If the flag is already set we know another thread is trying to

	 * suspend as well, so we leave the fs locked for this thread.

	 */

	error = -EINVAL;

	r = -EINVAL;

	down_write(&md->lock);

	if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {

		if (map)
@@ -1106,14 +1106,13 @@ int dm_suspend(struct mapped_device *md) 
	remove_wait_queue(&md->wait, &wait);



	/* were we interrupted ? */

	error = -EINTR;

	r = -EINTR;

	if (atomic_read(&md->pending))

		goto out_unfreeze;



	set_bit(DMF_SUSPENDED, &md->flags);



	map = dm_get_table(md);

	if (map)

	dm_table_postsuspend_targets(map);

	dm_table_put(map);

	up_write(&md->lock);
@@ -1125,25 +1124,29 @@ int dm_suspend(struct mapped_device *md) 
	clear_bit(DMF_BLOCK_IO, &md->flags);

out_write_unlock:

	up_write(&md->lock);

	return error;

	return r;



out_read_unlock:

	up_read(&md->lock);

	return error;

	return r;

}



int dm_resume(struct mapped_device *md)

{

	int r = -EINVAL;

	struct bio *def;

	struct dm_table *map = dm_get_table(md);

	struct dm_table *map = NULL;



	down_write(&md->lock);

	if (!map ||

	    !test_bit(DMF_SUSPENDED, &md->flags) ||

	    !dm_table_get_size(map)) {

	if (!dm_suspended(md)) {

		up_write(&md->lock);

		dm_table_put(map);

		return -EINVAL;

		goto out;

	}



	map = dm_get_table(md);

	if (!map || !dm_table_get_size(map)) {

		up_write(&md->lock);

		goto out;

	}



	dm_table_resume_targets(map);
@@ -1155,9 +1158,11 @@ int dm_resume(struct mapped_device *md) 
	up_write(&md->lock);

	__unlock_fs(md);

	dm_table_unplug_all(map);

	dm_table_put(map);



	return 0;

	r = 0;

out:

	dm_table_put(map);

	return r;

}



/*-----------------------------------------------------------------