Ceph » CephFS

Saw this crash happening on a Jewel 10.2.3 MDS when it was missing a object in the metadata pool:

2016-12-07 08:29:58.852595 7f3d74c96700 -1 log_channel(cluster) log [ERR] : dir 10011a4767b object missing on disk; some files may be lost
2016-12-07 08:29:58.855070 7f3d74c96700 -1 mds/MDCache.cc: In function 'virtual void C_MDC_OpenInoTraverseDir::finish(int)' thread 7f3d74c96700 time 2016-12-07 08:29:58.852637
mds/MDCache.cc: 8213: FAILED assert(r >= 0)

ceph version 10.2.3 (ecc23778eb545d8dd55e2e4735b53cc93f92e65b)
1: (ceph::__ceph_assert_fail(char const*, char const*, int, char const*)+0x85) [0x7f3d7fbe3a45]
2: (C_MDC_OpenInoTraverseDir::finish(int)+0x13e) [0x7f3d7f93d59e]
3: (MDSInternalContextBase::complete(int)+0x1eb) [0x7f3d7fa408ab]
4: (CDir::finish_waiting(unsigned long, int)+0x324) [0x7f3d7f9bb5a4]
5: (CDir::_omap_fetched(ceph::buffer::list&, std::map<std::string, ceph::buffer::list, std::less<std::string>, std::allocator<std::pair<std::string const, ceph::buffer::list> > >&, std::string const&, int)+0x65a) [0x7f3d7f9d29ba]
6: (CDir::_tmap_fetched(ceph::buffer::list&, std::string const&, int)+0x368) [0x7f3d7f9d40f8]
7: (MDSIOContextBase::complete(int)+0xa4) [0x7f3d7fa40bd4]
8: (Finisher::finisher_thread_entry()+0x27d) [0x7f3d7fb0f17d]
9: (()+0x7dc5) [0x7f3d7e9ccdc5]
10: (clone()+0x6d) [0x7f3d7d497ced]
NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.

As per discussion on the ceph-users list I'm opening this issue so that the MDS can be patched to record damaged metadata and continue it's operation.