From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ilya Dryomov Subject: Re: [PATCH v6 4/7] libceph: add an epoch_barrier field to struct ceph_osd_client Date: Tue, 4 Apr 2017 17:00:04 +0200 Message-ID: References: <20170330180546.11021-1-jlayton@redhat.com> <20170330180707.11137-1-jlayton@redhat.com> <20170330180707.11137-4-jlayton@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from mail-vk0-f65.google.com ([209.85.213.65]:35150 "EHLO mail-vk0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753254AbdDDPAF (ORCPT ); Tue, 4 Apr 2017 11:00:05 -0400 Received: by mail-vk0-f65.google.com with SMTP id z204so23178651vkd.2 for ; Tue, 04 Apr 2017 08:00:05 -0700 (PDT) In-Reply-To: <20170330180707.11137-4-jlayton@redhat.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Jeff Layton Cc: "Yan, Zheng" , Sage Weil , John Spray , Ceph Development On Thu, Mar 30, 2017 at 8:07 PM, Jeff Layton wrote: > Cephfs can get cap update requests that contain a new epoch barrier in > them. When that happens we want to pause all OSD traffic until the right > map epoch arrives. > > Add an epoch_barrier field to ceph_osd_client that is protected by the > osdc->lock rwsem. When the barrier is set, and the current OSD map > epoch is below that, pause the request target when submitting the > request or when revisiting it. Add a way for upper layers (cephfs) > to update the epoch_barrier as well. > > If we get a new map, compare the new epoch against the barrier before > kicking requests and request another map if the map epoch is still lower > than the one we want. > > If we get a map with a full pool, or at quota condition, then set the > barrier to the current epoch value. > > Reviewed-by: "Yan, Zheng=E2=80=9D > Signed-off-by: Jeff Layton > --- > include/linux/ceph/osd_client.h | 2 ++ > net/ceph/debugfs.c | 3 ++- > net/ceph/osd_client.c | 48 +++++++++++++++++++++++++++++++++--= ------ > 3 files changed, 43 insertions(+), 10 deletions(-) > > diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_cli= ent.h > index 8cf644197b1a..85650b415e73 100644 > --- a/include/linux/ceph/osd_client.h > +++ b/include/linux/ceph/osd_client.h > @@ -267,6 +267,7 @@ struct ceph_osd_client { > struct rb_root osds; /* osds */ > struct list_head osd_lru; /* idle osds */ > spinlock_t osd_lru_lock; > + u32 epoch_barrier; > struct ceph_osd homeless_osd; > atomic64_t last_tid; /* tid of last request */ > u64 last_linger_id; > @@ -305,6 +306,7 @@ extern void ceph_osdc_handle_reply(struct ceph_osd_cl= ient *osdc, > struct ceph_msg *msg); > extern void ceph_osdc_handle_map(struct ceph_osd_client *osdc, > struct ceph_msg *msg); > +void ceph_osdc_update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb= ); > > extern void osd_req_op_init(struct ceph_osd_request *osd_req, > unsigned int which, u16 opcode, u32 flags); > diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c > index d7e63a4f5578..71ba13927b3d 100644 > --- a/net/ceph/debugfs.c > +++ b/net/ceph/debugfs.c > @@ -62,7 +62,8 @@ static int osdmap_show(struct seq_file *s, void *p) > return 0; > > down_read(&osdc->lock); > - seq_printf(s, "epoch %d flags 0x%x\n", map->epoch, map->flags); > + seq_printf(s, "epoch %u barrier %u flags 0x%x\n", map->epoch, > + osdc->epoch_barrier, map->flags); > > for (n =3D rb_first(&map->pg_pools); n; n =3D rb_next(n)) { > struct ceph_pg_pool_info *pi =3D > diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c > index 4e56cd1ec265..3a94e8a1c7ff 100644 > --- a/net/ceph/osd_client.c > +++ b/net/ceph/osd_client.c > @@ -1298,8 +1298,9 @@ static bool target_should_be_paused(struct ceph_osd= _client *osdc, > __pool_full(pi); > > WARN_ON(pi->id !=3D t->base_oloc.pool); > - return (t->flags & CEPH_OSD_FLAG_READ && pauserd) || > - (t->flags & CEPH_OSD_FLAG_WRITE && pausewr); > + return ((t->flags & CEPH_OSD_FLAG_READ) && pauserd) || > + ((t->flags & CEPH_OSD_FLAG_WRITE) && pausewr) || > + (osdc->osdmap->epoch < osdc->epoch_barrier); > } > > enum calc_target_result { > @@ -1609,13 +1610,15 @@ static void send_request(struct ceph_osd_request = *req) > static void maybe_request_map(struct ceph_osd_client *osdc) > { > bool continuous =3D false; > + u32 epoch =3D osdc->osdmap->epoch; > > verify_osdc_locked(osdc); > - WARN_ON(!osdc->osdmap->epoch); > + WARN_ON_ONCE(epoch =3D=3D 0); > > if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) || > ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD) || > - ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) { > + ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR) || > + epoch < osdc->epoch_barrier) { > dout("%s osdc %p continuous\n", __func__, osdc); > continuous =3D true; > } else { Looks like this hunk is smaller now, but I thought we agreed to drop it entirely? "epoch < osdc->epoch_barrier" isn't there in Objecter. > @@ -1653,8 +1656,13 @@ static void __submit_request(struct ceph_osd_reque= st *req, bool wrlocked) > goto promote; > } > > - if ((req->r_flags & CEPH_OSD_FLAG_WRITE) && > - ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) { > + if (osdc->osdmap->epoch < osdc->epoch_barrier) { > + dout("req %p epoch %u barrier %u\n", req, osdc->osdmap->e= poch, > + osdc->epoch_barrier); > + req->r_t.paused =3D true; > + maybe_request_map(osdc); > + } else if ((req->r_flags & CEPH_OSD_FLAG_WRITE) && > + ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) { > dout("req %p pausewr\n", req); > req->r_t.paused =3D true; > maybe_request_map(osdc); > @@ -1808,7 +1816,8 @@ static void abort_request(struct ceph_osd_request *= req, int err) > > /* > * Drop all pending requests that are stalled waiting on a full conditio= n to > - * clear, and complete them with ENOSPC as the return code. > + * clear, and complete them with ENOSPC as the return code. Set the > + * osdc->epoch_barrier to the latest replay version epoch that was abort= ed. This comment needs an update -- replay version is gone... > */ > static void ceph_osdc_abort_on_full(struct ceph_osd_client *osdc) > { > @@ -1836,8 +1845,10 @@ static void ceph_osdc_abort_on_full(struct ceph_os= d_client *osdc) > abort_request(req, -ENOSPC); > } > } > + /* Update the epoch barrier to current epoch */ > + osdc->epoch_barrier =3D osdc->osdmap->epoch; How important is it to update the epoch barrier only if something was aborted? Being here doesn't mean that something was actually aborted. > out: > - dout("return abort_on_full\n"); > + dout("return abort_on_full barrier=3D%u\n", osdc->epoch_barrier); > } > > static void check_pool_dne(struct ceph_osd_request *req) > @@ -3293,7 +3304,8 @@ void ceph_osdc_handle_map(struct ceph_osd_client *o= sdc, struct ceph_msg *msg) > pausewr =3D ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR) || > ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) || > have_pool_full(osdc); > - if (was_pauserd || was_pausewr || pauserd || pausewr) > + if (was_pauserd || was_pausewr || pauserd || pausewr || > + osdc->osdmap->epoch < osdc->epoch_barrier) > maybe_request_map(osdc); > > kick_requests(osdc, &need_resend, &need_resend_linger); > @@ -3311,6 +3323,24 @@ void ceph_osdc_handle_map(struct ceph_osd_client *= osdc, struct ceph_msg *msg) > up_write(&osdc->lock); > } > > +void ceph_osdc_update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb= ) > +{ > + down_read(&osdc->lock); > + if (unlikely(eb > osdc->epoch_barrier)) { > + up_read(&osdc->lock); > + down_write(&osdc->lock); > + if (osdc->epoch_barrier < eb) { Nit: make it "eb > osdc->epoch_barrier" so it matches the unlikely condition. Thanks, Ilya