netfs: Fix looping in wait functions

netfs: Fix looping in wait functions

netfs_wait_for_request() and netfs_wait_for_pause() can loop forever if
netfs_collect_in_app() returns 2, indicating that it wants to repeat
because the ALL_QUEUED flag isn't yet set and there are no subreqs left
that haven't been collected.

The problem is that, unless collection is offloaded (OFFLOAD_COLLECTION),
we have to return to the application thread to continue and eventually set
ALL_QUEUED after pausing to deal with a retry - but we never get there.

Fix this by inserting checks for the IN_PROGRESS and PAUSE flags as
appropriate before cycling round - and add cond_resched() for good measure.

Fixes: 2b1424cd131c ("netfs: Fix wait/wake to be consistent about the waitqueue used")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/20250701163852.2171681-5-dhowells@redhat.com
Tested-by: Steve French <sfrench@samba.org>
Reviewed-by: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>