From b0494532214bdfbf241e94fabab5dd46f7b82631 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Mon, 11 May 2015 17:53:10 +0300 Subject: [PATCH] libceph: request a new osdmap if lingering request maps to no osd This commit does two things. First, if there are any homeless lingering requests, we now request a new osdmap even if the osdmap that is being processed brought no changes, i.e. if a given lingering request turned homeless in one of the previous epochs and remained homeless in the current epoch. Not doing so leaves us with a stale osdmap and as a result we may miss our window for reestablishing the watch and lose notifies. MON=1 OSD=1: # cat linger-needmap.sh #!/bin/bash rbd create --size 1 test DEV=$(rbd map test) ceph osd out 0 rbd map dne/dne # obtain a new osdmap as a side effect (!) sleep 1 ceph osd in 0 rbd resize --size 2 test # rbd info test | grep size -> 2M # blockdev --getsize $DEV -> 1M N.B.: Not obtaining a new osdmap in between "osd out" and "osd in" above is enough to make it miss that resize notify, but that is a bug^Wlimitation of ceph watch/notify v1. Second, homeless lingering requests are now kicked just like those lingering requests whose mapping has changed. This is mainly to recognize that a homeless lingering request makes no sense and to preserve the invariant that a registered lingering request is not sitting on any of r_req_lru_item lists. This spares us a WARN_ON, which commit ba9d114ec557 ("libceph: clear r_req_lru_item in __unregister_linger_request()") tried to fix the _wrong_ way. Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Ilya Dryomov Reviewed-by: Sage Weil --- net/ceph/osd_client.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index 41a4abc7e98e..31d4b1ebff01 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -2017,20 +2017,29 @@ static void kick_requests(struct ceph_osd_client *osdc, bool force_resend, err = __map_request(osdc, req, force_resend || force_resend_writes); dout("__map_request returned %d\n", err); - if (err == 0) - continue; /* no change and no osd was specified */ if (err < 0) continue; /* hrm! */ - if (req->r_osd == NULL) { - dout("tid %llu maps to no valid osd\n", req->r_tid); - needmap++; /* request a newer map */ - continue; - } + if (req->r_osd == NULL || err > 0) { + if (req->r_osd == NULL) { + dout("lingering %p tid %llu maps to no osd\n", + req, req->r_tid); + /* + * A homeless lingering request makes + * no sense, as it's job is to keep + * a particular OSD connection open. + * Request a newer map and kick the + * request, knowing that it won't be + * resent until we actually get a map + * that can tell us where to send it. + */ + needmap++; + } - dout("kicking lingering %p tid %llu osd%d\n", req, req->r_tid, - req->r_osd ? req->r_osd->o_osd : -1); - __register_request(osdc, req); - __unregister_linger_request(osdc, req); + dout("kicking lingering %p tid %llu osd%d\n", req, + req->r_tid, req->r_osd ? req->r_osd->o_osd : -1); + __register_request(osdc, req); + __unregister_linger_request(osdc, req); + } } reset_changed_osds(osdc); mutex_unlock(&osdc->request_mutex); -- 2.20.1