Ceph

https://github.com/ceph/ceph/pull/5892

On Fri, 11 Sep 2015, Haomai Wang wrote:

On Fri, Sep 11, 2015 at 8:56 PM, Sage Weil <sage@newdream.net> wrote:
On Fri, 11 Sep 2015, ?? wrote:

Thank Sage Weil:

1. I delete some testing pools in the past, but is was a long

time ago (may be 2 months ago), in recently upgrade, do not
delete pools.

2.? ceph osd dump please see the (attachment file

ceph.osd.dump.log)

3. debug osd = 20' and 'debug filestore = 20? (attachment file

ceph.osd.5.log.tar.gz)

This one is failing on pool 54, which has been deleted.? In this
case you
can work around it by renaming current/54.* out of the way.

4. i install the ceph-test, but output error
ceph-kvstore-tool /ceph/data5/current/db list
Invalid argument: /ceph/data5/current/db: does not exist

(create_if_missing is false)

Sorry, I should have said current/omap, not current/db.? I'm
still curious
to see the key dump.? I'm not sure why the leveldb key for these
pgs is
missing...

Yesterday I have a chat with wangrui and the reason is "infos"(legacy oid)
is missing. I'm not sure why it's missing.

Probably

https://github.com/ceph/ceph/blob/hammer/src/osd/OSD.cc#L2908

Oh, I think I see what happened:

- the pg removal was aborted pre-hammer.  On pre-hammer, thsi means that
load_pgs skips it here:

https://github.com/ceph/ceph/blob/firefly/src/osd/OSD.cc#L2121

- we upgrade to hammer.  we skip this pg (same reason), don't upgrade it,
but delete teh legacy infos object

https://github.com/ceph/ceph/blob/hammer/src/osd/OSD.cc#L2908

- now we see this crash...

I think the fix is, in hammer, to bail out of peek_map_epoch if the infos
object isn't present, here

https://github.com/ceph/ceph/blob/hammer/src/osd/PG.cc#L2867

Probably we should restructure so we can return a 'fail' value
instead of a magic epoch_t meaning the same...