From 4c238e30774e3022a505fa54311273add7570f13 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 11 Jul 2025 16:10:00 +0100 Subject: [PATCH] netfs: Fix copy-to-cache so that it performs collection with ceph+fscache The netfs copy-to-cache that is used by Ceph with local caching sets up a new request to write data just read to the cache. The request is started and then left to look after itself whilst the app continues. The request gets notified by the backing fs upon completion of the async DIO write, but then tries to wake up the app because NETFS_RREQ_OFFLOAD_COLLECTION isn't set - but the app isn't waiting there, and so the request just hangs. Fix this by setting NETFS_RREQ_OFFLOAD_COLLECTION which causes the notification from the backing filesystem to put the collection onto a work queue instead. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reported-by: Max Kellermann Link: https://lore.kernel.org/r/CAKPOu+8z_ijTLHdiCYGU_Uk7yYD=shxyGLwfe-L7AV3DhebS3w@mail.gmail.com/ Signed-off-by: David Howells Link: https://lore.kernel.org/20250711151005.2956810-2-dhowells@redhat.com Reviewed-by: Paulo Alcantara (Red Hat) cc: Paulo Alcantara cc: Viacheslav Dubeyko cc: Alex Markuze cc: Ilya Dryomov cc: netfs@lists.linux.dev cc: ceph-devel@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: stable@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/read_pgpriv2.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/netfs/read_pgpriv2.c b/fs/netfs/read_pgpriv2.c index 5bbe906a551d5..080d2a6a51d9d 100644 --- a/fs/netfs/read_pgpriv2.c +++ b/fs/netfs/read_pgpriv2.c @@ -110,6 +110,7 @@ static struct netfs_io_request *netfs_pgpriv2_begin_copy_to_cache( if (!creq->io_streams[1].avail) goto cancel_put; + __set_bit(NETFS_RREQ_OFFLOAD_COLLECTION, &creq->flags); trace_netfs_write(creq, netfs_write_trace_copy_to_cache); netfs_stat(&netfs_n_wh_copy_to_cache); rreq->copy_to_cache = creq; -- 2.47.2