From 20d72b00ca814d748f5663484e5c53bb2bf37a3a Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 19 May 2025 10:07:03 +0100 Subject: netfs: Fix the request's work item to not require a ref When the netfs_io_request struct's work item is queued, it must be supplied with a ref to the work item struct to prevent it being deallocated whilst on the queue or whilst it is being processed. This is tricky to manage as we have to get a ref before we try and queue it and then we may find it's already queued and is thus already holding a ref - in which case we have to try and get rid of the ref again. The problem comes if we're in BH or IRQ context and need to drop the ref: if netfs_put_request() reduces the count to 0, we have to do the cleanup - but the cleanup may need to wait. Fix this by adding a new work item to the request, ->cleanup_work, and dispatching that when the refcount hits zero. That can then synchronously cancel any outstanding work on the main work item before doing the cleanup. Adding a new work item also deals with another problem upstream where it's sometimes changing the work func in the put function and requeuing it - which has occasionally in the past caused the cleanup to happen incorrectly. As a bonus, this allows us to get rid of the 'was_async' parameter from a bunch of functions. This indicated whether the put function might not be permitted to sleep. Fixes: 3d3c95046742 ("netfs: Provide readahead and readpage netfs helpers") Signed-off-by: David Howells Link: https://lore.kernel.org/20250519090707.2848510-4-dhowells@redhat.com cc: Paulo Alcantara cc: Marc Dionne cc: Steve French cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- include/trace/events/netfs.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'include/trace') diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index f880835f7695..402c5e82e7b8 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -30,6 +30,7 @@ EM(netfs_write_trace_dio_write, "DIO-WRITE") \ EM(netfs_write_trace_unbuffered_write, "UNB-WRITE") \ EM(netfs_write_trace_writeback, "WRITEBACK") \ + EM(netfs_write_trace_writeback_single, "WB-SINGLE") \ E_(netfs_write_trace_writethrough, "WRITETHRU") #define netfs_rreq_origins \ @@ -128,17 +129,15 @@ #define netfs_rreq_ref_traces \ EM(netfs_rreq_trace_get_for_outstanding,"GET OUTSTND") \ EM(netfs_rreq_trace_get_subreq, "GET SUBREQ ") \ - EM(netfs_rreq_trace_get_work, "GET WORK ") \ EM(netfs_rreq_trace_put_complete, "PUT COMPLT ") \ EM(netfs_rreq_trace_put_discard, "PUT DISCARD") \ EM(netfs_rreq_trace_put_failed, "PUT FAILED ") \ EM(netfs_rreq_trace_put_no_submit, "PUT NO-SUBM") \ EM(netfs_rreq_trace_put_return, "PUT RETURN ") \ EM(netfs_rreq_trace_put_subreq, "PUT SUBREQ ") \ - EM(netfs_rreq_trace_put_work, "PUT WORK ") \ - EM(netfs_rreq_trace_put_work_complete, "PUT WORK CP") \ - EM(netfs_rreq_trace_put_work_nq, "PUT WORK NQ") \ + EM(netfs_rreq_trace_put_work_ip, "PUT WORK IP ") \ EM(netfs_rreq_trace_see_work, "SEE WORK ") \ + EM(netfs_rreq_trace_see_work_complete, "SEE WORK CP") \ E_(netfs_rreq_trace_new, "NEW ") #define netfs_sreq_ref_traces \ -- cgit v1.2.3