Ceph » CephFS

https://github.com/ceph/ceph/pull/11225

the buggy code was newly introduced, which does not exist in jewel

the jewel hang is different bug

 has_dir_layout 0x7f9d4e02be00)
    -2> 2016-08-28 17:07:42.285819 7f9d3a694700 10 client.4138 remove_cap mds.0 on 1.head(faked_ino=0 ref=0 ll_ref=0 cap_refs={1024=0} open={} mode=41777 size=0/0 mtime=2016-08-28 16:26:10.603274 caps=p(0=p) has_dir_layout 0x7f9d4e02be00)
    -1> 2016-08-28 17:07:42.285829 7f9d3a694700 10 client.4138 put_inode deleting 1.head(faked_ino=0 ref=0 ll_ref=0 cap_refs={1024=0} open={} mode=41777 size=0/0 mtime=2016-08-28 16:26:10.603274 caps=- has_dir_layout 0x7f9d4e02be00)
     0> 2016-08-28 17:07:42.393621 7f9d3a694700 -1 *** Caught signal (Segmentation fault) **
 in thread 7f9d3a694700 thread_name:ms_dispatch

 ceph version 10.2.2-503-g3168a84 (3168a8482211a2aaf9b4d715c0f7a920e896d9bb)
 1: (()+0x2a0e8a) [0x7f9d4319ee8a]
 2: (()+0xf100) [0x7f9d41c9e100]
 3: (Client::_invalidate_kernel_dcache()+0x33) [0x7f9d430adca3]
 4: (Client::trim_cache_for_reconnect(MetaSession*)+0x522) [0x7f9d430cfe52]
 5: (Client::handle_mds_map(MMDSMap*)+0x7ab) [0x7f9d430d180b]
 6: (Client::ms_dispatch(Message*)+0x63b) [0x7f9d4310cb1b]
 7: (DispatchQueue::entry()+0x78a) [0x7f9d433a89ca]
 8: (DispatchQueue::DispatchThread::entry()+0xd) [0x7f9d4327f5ad]
 9: (()+0x7dc5) [0x7f9d41c96dc5]
 10: (clone()+0x6d) [0x7f9d40b7d28d]
 NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.