mds: Dump the pool field after backpointers

The pool field of the inode backtrace should
be dumped after the backpointers are closed.

Signed-off-by: Sam Lang <sam.lang@inktank.com>
mds: Shift backtrace queuing on replay to lumps

Queuing backtraces on replay should be done with
the lumps instead of within the roots of the
metablob.  fullbits are added to lumps for
journal_primary_dentry(), which gets called for
all the operations we care about adding/updating
backtraces.

Signed-off-by: Sam Lang <sam.lang@inktank.com>
pybind/libcephfs:  Minor fixes

Signed-off-by: Sam Lang <sam.lang@inktank.com>
test/mds: Fixes to test-backtrace.py

Signed-off-by: Sam Lang <sam.lang@inktank.com>
message/mds:  Fix client reconnect decode

Flip the conditional so that snap realms are
decoded, otherwise this results in an assertion
failure of the mds when a client attempts to
reconnect.

Signed-off-by: Sam Lang <sam.lang@inktank.com>
client: Ensure inode/dentries are ref counted

The MetaRequest holds onto inodes and dentries
for retrying unsafe requests, but those objects
might be removed from the cache (unlink for example)
causing the inode/dentry to be freed.  Ensure that
the inode/dentry is never freed while the MetaRequest
holds onto it by putting/getting the refs using
set/get interfaces.

Signed-off-by: Sam Lang <sam.lang@inktank.com>