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Commit 2409f513 authored by Joe Thornber's avatar Joe Thornber Committed by Greg Kroah-Hartman
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dm thin: fix missing out-of-data-space to write mode transition if blocks are released 



commit 2c43fd26e46734430122b8d2ad3024bb532df3ef upstream.

Discard bios and thin device deletion have the potential to release data
blocks.  If the thin-pool is in out-of-data-space mode, and blocks were
released, transition the thin-pool back to full write mode.

The correct time to do this is just after the thin-pool metadata commit.
It cannot be done before the commit because the space maps will not
allow immediate reuse of the data blocks in case there's a rollback
following power failure.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 52259b6c

drivers/md/dm-thin.c

+20 −2
Original line number Diff line number Diff line
@@ -990,6 +990,24 @@ static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block, 
		schedule_zero(tc, virt_block, data_dest, cell, bio);

}



static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);



static void check_for_space(struct pool *pool)

{

	int r;

	dm_block_t nr_free;



	if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)

		return;



	r = dm_pool_get_free_block_count(pool->pmd, &nr_free);

	if (r)

		return;



	if (nr_free)

		set_pool_mode(pool, PM_WRITE);

}



/*

 * A non-zero return indicates read_only or fail_io mode.

 * Many callers don't care about the return value.
@@ -1004,6 +1022,8 @@ static int commit(struct pool *pool) 
	r = dm_pool_commit_metadata(pool->pmd);

	if (r)

		metadata_operation_failed(pool, "dm_pool_commit_metadata", r);

	else

		check_for_space(pool);



	return r;

}
@@ -1022,8 +1042,6 @@ static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks) 
	}

}



static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);



static int alloc_data_block(struct thin_c *tc, dm_block_t *result)

{

	int r;