mds: fix slave rename rollback

The main issue of old slave rename rollback code is that it assumes
all affected objects are in the cache. The assumption is not true
when MDS does rollback in the resolve stage. This patch removes the
assumption and makes Server::do_rename_rollback() check individual
object and roll back change.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: split reslove into two sub-stages

The resolve stage serves to disambiguate the fate of uncommitted slave
updates and resolve subtrees authority. The MDS sends resolve message
that claims subtrees authority immediately when reslove stage is entered,
When receiving a resolve message, the MDS also processes it immediately.
This may cause problem if there are uncommitted slave rename and some of
them need rollback later. It's because slave rename rollback may modify
subtree map.

The fix is split reslove into two sub-stages, the first sub-stage serves
to disambiguate slave updates, do slave commit or rollback. After the
the first sub-stage finishes, the MDS sends resolve messages that claim
subtrees authority to other MDS and processes received resolve messages.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: send resolve messages after all MDS reach resolve stage

Current code sends resolve messages when resolving MDS set changes.
There is no need to send resolve messages when some MDS leave the
resolve stage. Sending message while some MDS are replaying is also
not very useful.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: Always use {push,pop}_projected_linkage to change linkage

Current code skips using {push,pop}_projected_linkage to modify replica
dentry's linkage. This confuses EMetaBlob::add_dir_context() and makes
it record out-of-date path when TO_ROOT mode is used. This patch changes
the code to always use {push,pop}_projected_linkage to modify dentry's
linkage. It makes sure MDCache::create_subtree_map() record correct and
up-to-date subtree map.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: don't replace existing slave request

The MDS may receive a client request, but find there is an existing
slave request. It means other MDS is handling the same request, so
we should not replace the slave request with a new client request,
just forward the request.

The client request may include embeded cap releases, we need process
them even the request is forwarded.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: fix for MDCache::adjust_bounded_subtree_auth

After swallowing extra subtrees, subtree bounds may change, so it
should re-check.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: fix for MDCache::disambiguate_imports

In the resolve stage, if no MDS claims other MDS's disambiguous subtree
import, the subtree's dir_auth is undefined.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: journal inode's projected parent when doing link rollback

Otherwise the journal entry will revert the effect of any on-going
rename operation for the inode.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: don't journal opened non-auth inode

If we journal opened non-auth inode, during journal replay, the corresponding
entry will add non-auth objects to the cache. But the MDS does not journal all
subsequent modifications (rmdir,rename) to these non-auth objects, so the code
that manages cache and subtree may get confused. Besides non-auth objects will
be trimmed at the resolve stage.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: properly clear CDir::STATE_COMPLETE when replaying EImportStart

when replaying EImportStart, we should set/clear directory's COMPLETE
flag according with the flag in the journal entry.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: move variables special to rename into MDRequest::more

My previous patches add two pointers (ambiguous_auth_inode and
auth_pin_freeze) to class Mutation. They are both used by cross
authority rename, both point to the renamed inode. Later patches
need add more rename special state to MDRequest, So just move them
into MDRequest::more

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: rejoin remote wrlocks and frozen auth pin

Includes remote wrlocks and frozen authpin in cache rejoin strong message

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: fetch missing inodes from disk

The problem of fetching missing inodes from replicas is that replicated inodes
does not have up-to-date rstat and fragstat. So just fetch missing inodes from
disk

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: add projected rename's subtree bounds to ESubtreeMap

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: fix 'discover' handling in the rejoin stage

If the MDS is the resolve stage, current MDCache::handle_discover() only handles
'discover' from MDS that it has already gotten rejoin acknowledgement. This can
cause circular wait because MDCache::rejoin_gather_finish() fetches reconnected
inodes before send rejoin acknowledgements, and fetching reconnected inode may
triggers 'discover'. The fix is not delay handling 'discover' from MDS that are
also in the rejoin stage.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: allow handling slave request in the clientreplay stage

replaying a client request may need to create slave request and the slave
MDS can be also in the clientreplay stage.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: mark export bounds for cross authority directory rename

this guarantees that the importing MDS gets directory fragment's
up-to-date fragstat/rstat.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
mds: clear inode dirty after slave rename finishes.

The inode is linked to a non-auth directory, so remove it from LogSegment's
dirty inode list.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>