Hmm, this is definitely narrowing the race (probably enough to never hit it), but it's not actually eliminating it (if the restart happens after 4 billion requests…). More importantly this kind of symptom makes me worry that we might be papering over more serious issues with colliding states in the Table on restart. I don't have the MDSTable semantics in my head so I'll need to look into this later unless somebody else volunteers to do so… -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com On Sunday, March 17, 2013 at 7:51 AM, Yan, Zheng wrote: > From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx> > > When a MDS becomes active, the table server re-sends 'agree' messages > for old prepared request. If the recoverd MDS starts a new table request > at the same time, The new request's ID can happen to be the same as old > prepared request's ID, because current table client assigns request ID > from zero after MDS restarts. > > Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx (mailto:zheng.z.yan@xxxxxxxxx)> > --- > src/mds/MDS.cc (http://MDS.cc) | 3 +++ > src/mds/MDSTableClient.cc (http://MDSTableClient.cc) | 5 +++++ > src/mds/MDSTableClient.h | 2 ++ > 3 files changed, 10 insertions(+) > > diff --git a/src/mds/MDS.cc (http://MDS.cc) b/src/mds/MDS.cc (http://MDS.cc) > index bb1c833..859782a 100644 > --- a/src/mds/MDS.cc (http://MDS.cc) > +++ b/src/mds/MDS.cc (http://MDS.cc) > @@ -1212,6 +1212,9 @@ void MDS::boot_start(int step, int r) > dout(2) << "boot_start " << step << ": opening snap table" << dendl; > snapserver->load(gather.new_sub()); > } > + > + anchorclient->init(); > + snapclient->init(); > > dout(2) << "boot_start " << step << ": opening mds log" << dendl; > mdlog->open(gather.new_sub()); > diff --git a/src/mds/MDSTableClient.cc (http://MDSTableClient.cc) b/src/mds/MDSTableClient.cc (http://MDSTableClient.cc) > index ea021f5..beba0a3 100644 > --- a/src/mds/MDSTableClient.cc (http://MDSTableClient.cc) > +++ b/src/mds/MDSTableClient.cc (http://MDSTableClient.cc) > @@ -34,6 +34,11 @@ > #undef dout_prefix > #define dout_prefix *_dout << "mds." << mds->get_nodeid() << ".tableclient(" << get_mdstable_name(table) << ") " > > +void MDSTableClient::init() > +{ > + // make reqid unique between MDS restarts > + last_reqid = (uint64_t)mds->mdsmap->get_epoch() << 32; > +} > > void MDSTableClient::handle_request(class MMDSTableRequest *m) > { > diff --git a/src/mds/MDSTableClient.h b/src/mds/MDSTableClient.h > index e15837f..78035db 100644 > --- a/src/mds/MDSTableClient.h > +++ b/src/mds/MDSTableClient.h > @@ -63,6 +63,8 @@ public: > MDSTableClient(MDS *m, int tab) : mds(m), table(tab), last_reqid(0) {} > virtual ~MDSTableClient() {} > > + void init(); > + > void handle_request(MMDSTableRequest *m); > > void _prepare(bufferlist& mutation, version_t *ptid, bufferlist *pbl, Context *onfinish); > -- > 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
