dm thin: allow metadata commit if pool is in PM_OUT_OF_DATA_SPACE mode

commit 8d07e8a5 upstream.

Commit 3e1a0699 ("dm thin: fix out of data space handling") introduced
a regression in the metadata commit() method by returning an error if
the pool is in PM_OUT_OF_DATA_SPACE mode.  This oversight caused a thin
device to return errors even if the default queue_if_no_space ENOSPC
handling mode is used.

Fix commit() to only fail if pool is in PM_READ_ONLY or PM_FAIL mode.

Reported-by: qindehua@163.com
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/md/dm-thin.c

@@ -920,7 +920,7 @@ static int commit(struct pool *pool)
 {
 	int r;
 
-	if (get_pool_mode(pool) != PM_WRITE)
+	if (get_pool_mode(pool) >= PM_READ_ONLY)
 		return -EINVAL;
 
 	r = dm_pool_commit_metadata(pool->pmd);