block: Fix blk->in_flight during blk_wait_while_drained()

Waiting in blk_wait_while_drained() while blk->in_flight is increased
for the current request is wrong because it will cause the drain
operation to deadlock.

This patch makes sure that blk_wait_while_drained() is called with
blk->in_flight increased exactly once for the current request, and that
it temporarily decreases the counter while it waits.

Fixes: cf3129323f900ef5ddbccbe86e4fa801e88c566e
Signed-off-by: Kevin Wolf <>
Reviewed-by: Vladimir Sementsov-Ogievskiy <>
Reviewed-by: Max Reitz <>
Message-Id: <>
Signed-off-by: Kevin Wolf <>
1 file changed