cephfs: mtime should not update rctime

mtime is a user modifiable field and someone can alter it to reflect a modification time in the future or past.
rctime should be depended only on ctime which itself is system depended (based on how POSIX works).
By setting an mtime in the future, we render the usage of rctime redundant until the future timestamp is met.

Signed-off-by: Theofilos Mouratidis <t.mour@cern.ch>

src/mds/Locker.cc

@@ -2849,11 +2849,9 @@ bool Locker::check_inode_max_size(CInode *in, bool force_wrlock,
     pi.inode->rstat.rbytes = new_size;
     dout(10) << "check_inode_max_size mtime " << pi.inode->mtime << " -> " << new_mtime << dendl;
     pi.inode->mtime = new_mtime;
-    if (new_mtime > pi.inode->ctime) {
-      pi.inode->ctime = new_mtime;
-      if (new_mtime > pi.inode->rstat.rctime)
-	pi.inode->rstat.rctime = new_mtime;
-    }
+    pi.inode->ctime = ceph_clock_now();
+    if (pi.inode->ctime > pi.inode->rstat.rctime)
+      pi.inode->rstat.rctime = pi.inode->ctime;
   }
 
   // use EOpen if the file is still open; otherwise, use EUpdate.
@@ -3684,8 +3682,6 @@ void Locker::_update_cap_fields(CInode *in, int dirty, const cref_t<MClientCaps>
       dout(7) << "  mtime " << pi->mtime << " -> " << mtime
 	      << " for " << *in << dendl;
       pi->mtime = mtime;
-      if (mtime > pi->rstat.rctime)
-	pi->rstat.rctime = mtime;
     }
     if (in->is_file() &&   // ONLY if regular file
 	size > pi->size) {

src/mds/MDCache.cc

@@ -2220,12 +2220,6 @@ void MDCache::predirty_journal_parents(MutationRef mut, EMetaBlob *blob,
 	pf->fragstat.mtime = mut->get_op_stamp();
 	pf->fragstat.change_attr++;
 	dout(10) << "predirty_journal_parents bumping change_attr to " << pf->fragstat.change_attr << " on " << parent << dendl;
-	if (pf->fragstat.mtime > pf->rstat.rctime) {
-	  dout(10) << "predirty_journal_parents updating mtime on " << *parent << dendl;
-	  pf->rstat.rctime = pf->fragstat.mtime;
-	} else {
-	  dout(10) << "predirty_journal_parents updating mtime UNDERWATER on " << *parent << dendl;
-	}
       }
       if (linkunlink) {
 	dout(10) << "predirty_journal_parents updating size on " << *parent << dendl;