diff --git a/contrib/perf.py b/contrib/perf.py
--- a/contrib/perf.py
+++ b/contrib/perf.py
@@ -2609,7 +2609,11 @@
     rl = cmdutil.openrevlog(repo, b'perfrevlogindex', file_, opts)
 
     opener = getattr(rl, 'opener')  # trick linter
-    indexfile = rl.indexfile
+    # compat with hg <= 5.8
+    indexfile = getattr(rl, '_indexfile', None)
+    if indexfile is None:
+        # compatibility with <= hg-5.8
+        indexfile = getattr(rl, 'indexfile')
     data = opener.read(indexfile)
 
     header = struct.unpack(b'>I', data[0:4])[0]
@@ -3031,7 +3035,11 @@
     if util.safehasattr(orig, k):
         revlogkwargs[k] = getattr(orig, k)
 
-    origindexpath = orig.opener.join(orig.indexfile)
+    indexfile = getattr(orig, '_indexfile', None)
+    if indexfile is None:
+        # compatibility with <= hg-5.8
+        indexfile = getattr(orig, 'indexfile')
+    origindexpath = orig.opener.join(indexfile)
     origdatapath = orig.opener.join(orig.datafile)
     indexname = 'revlog.i'
     dataname = 'revlog.d'
@@ -3127,7 +3135,11 @@
 
     def rlfh(rl):
         if rl._inline:
-            return getsvfs(repo)(rl.indexfile)
+            indexfile = getattr(rl, '_indexfile', None)
+            if indexfile is None:
+                # compatibility with <= hg-5.8
+                indexfile = getattr(rl, 'indexfile')
+            return getsvfs(repo)(indexfile)
         else:
             return getsvfs(repo)(rl.datafile)
 
diff --git a/mercurial/bundlerepo.py b/mercurial/bundlerepo.py
--- a/mercurial/bundlerepo.py
+++ b/mercurial/bundlerepo.py
@@ -84,12 +84,12 @@
             for p in (p1, p2):
                 if not self.index.has_node(p):
                     raise error.LookupError(
-                        p, self.indexfile, _(b"unknown parent")
+                        p, self._indexfile, _(b"unknown parent")
                     )
 
             if not self.index.has_node(deltabase):
                 raise LookupError(
-                    deltabase, self.indexfile, _(b'unknown delta base')
+                    deltabase, self._indexfile, _(b'unknown delta base')
                 )
 
             baserev = self.rev(deltabase)
@@ -180,7 +180,7 @@
             self,
             opener,
             (revlog_constants.KIND_CHANGELOG, None),
-            self.indexfile,
+            self._indexfile,
             cgunpacker,
             linkmapper,
         )
@@ -201,7 +201,7 @@
             self,
             opener,
             (revlog_constants.KIND_MANIFESTLOG, dir),
-            self._revlog.indexfile,
+            self._revlog._indexfile,
             cgunpacker,
             linkmapper,
         )
@@ -233,7 +233,7 @@
             opener,
             # XXX should use the unencoded path
             target=(revlog_constants.KIND_FILELOG, path),
-            indexfile=self._revlog.indexfile,
+            indexfile=self._revlog._indexfile,
             cgunpacker=cgunpacker,
             linkmapper=linkmapper,
         )
diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -804,10 +804,10 @@
                 # We failed to resolve a parent for this node, so
                 # we crash the changegroup construction.
                 if util.safehasattr(store, 'target'):
-                    target = store.indexfile
+                    target = store._indexfile
                 else:
                     # some revlog not actually a revlog
-                    target = store._revlog.indexfile
+                    target = store._revlog._indexfile
 
                 raise error.Abort(
                     b"unable to resolve parent while packing '%s' %r"
diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -452,13 +452,13 @@
         if not self._delayed:
             if len(self) == 0:
                 self._divert = True
-                if self._realopener.exists(self.indexfile + b'.a'):
-                    self._realopener.unlink(self.indexfile + b'.a')
-                self.opener = _divertopener(self._realopener, self.indexfile)
+                if self._realopener.exists(self._indexfile + b'.a'):
+                    self._realopener.unlink(self._indexfile + b'.a')
+                self.opener = _divertopener(self._realopener, self._indexfile)
             else:
                 self._delaybuf = []
                 self.opener = _delayopener(
-                    self._realopener, self.indexfile, self._delaybuf
+                    self._realopener, self._indexfile, self._delaybuf
                 )
         self._delayed = True
         tr.addpending(b'cl-%i' % id(self), self._writepending)
@@ -471,12 +471,12 @@
         # move redirected index data back into place
         if self._divert:
             assert not self._delaybuf
-            tmpname = self.indexfile + b".a"
+            tmpname = self._indexfile + b".a"
             nfile = self.opener.open(tmpname)
             nfile.close()
-            self.opener.rename(tmpname, self.indexfile, checkambig=True)
+            self.opener.rename(tmpname, self._indexfile, checkambig=True)
         elif self._delaybuf:
-            fp = self.opener(self.indexfile, b'a', checkambig=True)
+            fp = self.opener(self._indexfile, b'a', checkambig=True)
             fp.write(b"".join(self._delaybuf))
             fp.close()
             self._delaybuf = None
@@ -489,8 +489,8 @@
         pretxnchangegroup"""
         if self._delaybuf:
             # make a temporary copy of the index
-            fp1 = self._realopener(self.indexfile)
-            pendingfilename = self.indexfile + b".a"
+            fp1 = self._realopener(self._indexfile)
+            pendingfilename = self._indexfile + b".a"
             # register as a temp file to ensure cleanup on failure
             tr.registertmp(pendingfilename)
             # write existing data
@@ -502,7 +502,7 @@
             # switch modes so finalize can simply rename
             self._delaybuf = None
             self._divert = True
-            self.opener = _divertopener(self._realopener, self.indexfile)
+            self.opener = _divertopener(self._realopener, self._indexfile)
 
         if self._divert:
             return True
diff --git a/mercurial/filelog.py b/mercurial/filelog.py
--- a/mercurial/filelog.py
+++ b/mercurial/filelog.py
@@ -71,7 +71,7 @@
 
     def lookup(self, node):
         return storageutil.fileidlookup(
-            self._revlog, node, self._revlog.indexfile
+            self._revlog, node, self._revlog._indexfile
         )
 
     def linkrev(self, rev):
diff --git a/mercurial/repoview.py b/mercurial/repoview.py
--- a/mercurial/repoview.py
+++ b/mercurial/repoview.py
@@ -333,7 +333,7 @@
         r = super(filteredchangelogmixin, self).rev(node)
         if r in self.filteredrevs:
             raise error.FilteredLookupError(
-                hex(node), self.indexfile, _(b'filtered node')
+                hex(node), self._indexfile, _(b'filtered node')
             )
         return r
 
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -323,13 +323,13 @@
                 datafile = b'%s.%s' % (datafile, postfix)
         if postfix is not None:
             indexfile = b'%s.%s' % (indexfile, postfix)
-        self.indexfile = indexfile
+        self._indexfile = indexfile
         self.datafile = datafile
         self.nodemap_file = None
         self.postfix = postfix
         if persistentnodemap:
             self.nodemap_file = nodemaputil.get_nodemap_file(
-                opener, self.indexfile
+                opener, self._indexfile
             )
 
         self.opener = opener
@@ -490,7 +490,7 @@
             if flags:
                 raise error.RevlogError(
                     _(b'unknown flags (%#04x) in version %d revlog %s')
-                    % (flags >> 16, fmt, self.indexfile)
+                    % (flags >> 16, fmt, self._indexfile)
                 )
 
             self._inline = False
@@ -500,7 +500,7 @@
             if flags & ~REVLOGV1_FLAGS:
                 raise error.RevlogError(
                     _(b'unknown flags (%#04x) in version %d revlog %s')
-                    % (flags >> 16, fmt, self.indexfile)
+                    % (flags >> 16, fmt, self._indexfile)
                 )
 
             self._inline = versionflags & FLAG_INLINE_DATA
@@ -510,7 +510,7 @@
             if flags & ~REVLOGV2_FLAGS:
                 raise error.RevlogError(
                     _(b'unknown flags (%#04x) in version %d revlog %s')
-                    % (flags >> 16, fmt, self.indexfile)
+                    % (flags >> 16, fmt, self._indexfile)
                 )
 
             # There is a bug in the transaction handling when going from an
@@ -523,7 +523,7 @@
 
         else:
             raise error.RevlogError(
-                _(b'unknown version (%d) in revlog %s') % (fmt, self.indexfile)
+                _(b'unknown version (%d) in revlog %s') % (fmt, self._indexfile)
             )
 
         self.nodeconstants = sha1nodeconstants
@@ -578,7 +578,7 @@
                         index.update_nodemap_data(*nodemap_data)
         except (ValueError, IndexError):
             raise error.RevlogError(
-                _(b"index %s is corrupted") % self.indexfile
+                _(b"index %s is corrupted") % self._indexfile
             )
         self.index, self._chunkcache = d
         if not self._chunkcache:
@@ -604,7 +604,7 @@
             args['checkambig'] = self._checkambig
         if mode == b'w':
             args['atomictemp'] = True
-        return self.opener(self.indexfile, **args)
+        return self.opener(self._indexfile, **args)
 
     def _datafp(self, mode=b'r'):
         """file object for the revlog's data file"""
@@ -729,7 +729,7 @@
                 or node in self.nodeconstants.wdirfilenodeids
             ):
                 raise error.WdirUnsupported
-            raise error.LookupError(node, self.indexfile, _(b'no node'))
+            raise error.LookupError(node, self._indexfile, _(b'no node'))
 
     # Accessors for index entries.
 
@@ -1393,7 +1393,7 @@
             # fast path: for unfiltered changelog, radix tree is accurate
             if not getattr(self, 'filteredrevs', None):
                 raise error.AmbiguousPrefixLookupError(
-                    id, self.indexfile, _(b'ambiguous identifier')
+                    id, self._indexfile, _(b'ambiguous identifier')
                 )
             # fall through to slow path that filters hidden revisions
         except (AttributeError, ValueError):
@@ -1419,7 +1419,7 @@
                         self._pcache[id] = nl[0]
                         return nl[0]
                     raise error.AmbiguousPrefixLookupError(
-                        id, self.indexfile, _(b'ambiguous identifier')
+                        id, self._indexfile, _(b'ambiguous identifier')
                     )
                 if maybewdir:
                     raise error.WdirUnsupported
@@ -1439,7 +1439,7 @@
         if n:
             return n
 
-        raise error.LookupError(id, self.indexfile, _(b'no match found'))
+        raise error.LookupError(id, self._indexfile, _(b'no match found'))
 
     def shortest(self, node, minlength=1):
         """Find the shortest unambiguous prefix that matches node."""
@@ -1453,7 +1453,7 @@
                 # single 'ff...' match
                 return True
             if matchednode is None:
-                raise error.LookupError(node, self.indexfile, _(b'no node'))
+                raise error.LookupError(node, self._indexfile, _(b'no node'))
             return True
 
         def maybewdir(prefix):
@@ -1474,7 +1474,9 @@
                 return disambiguate(hexnode, length)
             except error.RevlogError:
                 if node != self.nodeconstants.wdirid:
-                    raise error.LookupError(node, self.indexfile, _(b'no node'))
+                    raise error.LookupError(
+                        node, self._indexfile, _(b'no node')
+                    )
             except AttributeError:
                 # Fall through to pure code
                 pass
@@ -1545,7 +1547,7 @@
                         b'offset %d, got %d'
                     )
                     % (
-                        self.indexfile if self._inline else self.datafile,
+                        self._indexfile if self._inline else self.datafile,
                         length,
                         realoffset,
                         len(d) - startoffset,
@@ -1561,7 +1563,7 @@
                     b'%d, got %d'
                 )
                 % (
-                    self.indexfile if self._inline else self.datafile,
+                    self._indexfile if self._inline else self.datafile,
                     length,
                     offset,
                     len(d),
@@ -1932,11 +1934,11 @@
                     revornode = templatefilters.short(hex(node))
                 raise error.RevlogError(
                     _(b"integrity check failed on %s:%s")
-                    % (self.indexfile, pycompat.bytestr(revornode))
+                    % (self._indexfile, pycompat.bytestr(revornode))
                 )
         except error.RevlogError:
             if self._censorable and storageutil.iscensoredtext(text):
-                raise error.CensoredNodeError(self.indexfile, node, text)
+                raise error.CensoredNodeError(self._indexfile, node, text)
             raise
 
     def _enforceinlinesize(self, tr, fp=None):
@@ -1953,10 +1955,10 @@
         ):
             return
 
-        troffset = tr.findoffset(self.indexfile)
+        troffset = tr.findoffset(self._indexfile)
         if troffset is None:
             raise error.RevlogError(
-                _(b"%s not found in the transaction") % self.indexfile
+                _(b"%s not found in the transaction") % self._indexfile
             )
         trindex = 0
         tr.add(self.datafile, 0)
@@ -1988,7 +1990,7 @@
             # the temp file replace the real index when we exit the context
             # manager
 
-        tr.replace(self.indexfile, trindex * self.index.entry_size)
+        tr.replace(self._indexfile, trindex * self.index.entry_size)
         nodemaputil.setup_persistent_nodemap(tr, self)
         self._chunkclear()
 
@@ -2024,7 +2026,7 @@
         """
         if link == nullrev:
             raise error.RevlogError(
-                _(b"attempted to add linkrev -1 to %s") % self.indexfile
+                _(b"attempted to add linkrev -1 to %s") % self._indexfile
             )
 
         if sidedata is None:
@@ -2049,7 +2051,7 @@
                 _(
                     b"%s: size of %d bytes exceeds maximum revlog storage of 2GiB"
                 )
-                % (self.indexfile, len(rawtext))
+                % (self._indexfile, len(rawtext))
             )
 
         node = node or self.hash(rawtext, p1, p2)
@@ -2220,14 +2222,14 @@
         """
         if node == self.nullid:
             raise error.RevlogError(
-                _(b"%s: attempt to add null revision") % self.indexfile
+                _(b"%s: attempt to add null revision") % self._indexfile
             )
         if (
             node == self.nodeconstants.wdirid
             or node in self.nodeconstants.wdirfilenodeids
         ):
             raise error.RevlogError(
-                _(b"%s: attempt to add wdir revision") % self.indexfile
+                _(b"%s: attempt to add wdir revision") % self._indexfile
             )
 
         if self._inline:
@@ -2247,12 +2249,12 @@
                 # offset is "as if" it were in the .d file, so we need to add on
                 # the size of the entry metadata.
                 self._concurrencychecker(
-                    ifh, self.indexfile, offset + curr * self.index.entry_size
+                    ifh, self._indexfile, offset + curr * self.index.entry_size
                 )
             else:
                 # Entries in the .i are a consistent size.
                 self._concurrencychecker(
-                    ifh, self.indexfile, curr * self.index.entry_size
+                    ifh, self._indexfile, curr * self.index.entry_size
                 )
                 self._concurrencychecker(dfh, self.datafile, offset)
 
@@ -2369,7 +2371,7 @@
         curr = len(self) - 1
         if not self._inline:
             transaction.add(self.datafile, offset)
-            transaction.add(self.indexfile, curr * len(entry))
+            transaction.add(self._indexfile, curr * len(entry))
             if data[0]:
                 dfh.write(data[0])
             dfh.write(data[1])
@@ -2378,7 +2380,7 @@
             ifh.write(entry)
         else:
             offset += curr * self.index.entry_size
-            transaction.add(self.indexfile, offset)
+            transaction.add(self._indexfile, offset)
             ifh.write(entry)
             ifh.write(data[0])
             ifh.write(data[1])
@@ -2417,10 +2419,10 @@
         ifh = self._indexfp(b"a+")
         isize = r * self.index.entry_size
         if self._inline:
-            transaction.add(self.indexfile, end + isize)
+            transaction.add(self._indexfile, end + isize)
             dfh = None
         else:
-            transaction.add(self.indexfile, isize)
+            transaction.add(self._indexfile, isize)
             transaction.add(self.datafile, end)
             dfh = self._datafp(b"a+")
 
@@ -2452,12 +2454,12 @@
                 for p in (p1, p2):
                     if not self.index.has_node(p):
                         raise error.LookupError(
-                            p, self.indexfile, _(b'unknown parent')
+                            p, self._indexfile, _(b'unknown parent')
                         )
 
                 if not self.index.has_node(deltabase):
                     raise error.LookupError(
-                        deltabase, self.indexfile, _(b'unknown delta base')
+                        deltabase, self._indexfile, _(b'unknown delta base')
                     )
 
                 baserev = self.rev(deltabase)
@@ -2470,7 +2472,7 @@
                     newlen = len(delta) - hlen
                     if delta[:hlen] != mdiff.replacediffheader(oldlen, newlen):
                         raise error.CensoredBaseError(
-                            self.indexfile, self.node(baserev)
+                            self._indexfile, self.node(baserev)
                         )
 
                 if not flags and self._peek_iscensored(baserev, delta, flush):
@@ -2575,7 +2577,7 @@
         else:
             end += rev * self.index.entry_size
 
-        transaction.add(self.indexfile, end)
+        transaction.add(self._indexfile, end)
 
         # then reset internal state in memory to forget those revisions
         self._revisioncache = None
@@ -2608,7 +2610,7 @@
             dd = 0
 
         try:
-            f = self.opener(self.indexfile)
+            f = self.opener(self._indexfile)
             f.seek(0, io.SEEK_END)
             actual = f.tell()
             f.close()
@@ -2629,7 +2631,7 @@
         return (dd, di)
 
     def files(self):
-        res = [self.indexfile]
+        res = [self._indexfile]
         if not self._inline:
             res.append(self.datafile)
         return res
@@ -2847,7 +2849,7 @@
                     flags = flags | new_flags[0] & ~new_flags[1]
 
                 ifh = destrevlog.opener(
-                    destrevlog.indexfile, b'a+', checkambig=False
+                    destrevlog._indexfile, b'a+', checkambig=False
                 )
                 dfh = None
                 if not destrevlog._inline:
@@ -2899,7 +2901,7 @@
             self.opener,
             target=self.target,
             postfix=b'tmpcensored',
-            indexfile=self.indexfile,
+            indexfile=self._indexfile,
             censorable=True,
         )
         newrl._format_version = self._format_version
@@ -2952,11 +2954,11 @@
                 rawtext, tr, self.linkrev(rev), p1, p2, node, self.flags(rev)
             )
 
-        tr.addbackup(self.indexfile, location=b'store')
+        tr.addbackup(self._indexfile, location=b'store')
         if not self._inline:
             tr.addbackup(self.datafile, location=b'store')
 
-        self.opener.rename(newrl.indexfile, self.indexfile)
+        self.opener.rename(newrl._indexfile, self._indexfile)
         if not self._inline:
             self.opener.rename(newrl.datafile, self.datafile)
 
@@ -2981,7 +2983,7 @@
         if version != state[b'expectedversion']:
             yield revlogproblem(
                 warning=_(b"warning: '%s' uses revlog format %d; expected %d")
-                % (self.indexfile, version, state[b'expectedversion'])
+                % (self._indexfile, version, state[b'expectedversion'])
             )
 
         state[b'skipread'] = set()
@@ -3079,7 +3081,7 @@
         d = {}
 
         if exclusivefiles:
-            d[b'exclusivefiles'] = [(self.opener, self.indexfile)]
+            d[b'exclusivefiles'] = [(self.opener, self._indexfile)]
             if not self._inline:
                 d[b'exclusivefiles'].append((self.opener, self.datafile))
 
diff --git a/mercurial/revlogutils/nodemap.py b/mercurial/revlogutils/nodemap.py
--- a/mercurial/revlogutils/nodemap.py
+++ b/mercurial/revlogutils/nodemap.py
@@ -149,7 +149,7 @@
     if revlog.nodemap_file is None:
         if force:
             revlog.nodemap_file = get_nodemap_file(
-                revlog.opener, revlog.indexfile
+                revlog.opener, revlog._indexfile
             )
         else:
             msg = "calling persist nodemap on a revlog without the feature enabled"
diff --git a/mercurial/unionrepo.py b/mercurial/unionrepo.py
--- a/mercurial/unionrepo.py
+++ b/mercurial/unionrepo.py
@@ -165,7 +165,7 @@
         linkmapper = None
         changelog2 = changelog.changelog(opener2)
         unionrevlog.__init__(
-            self, opener, self.indexfile, changelog2, linkmapper
+            self, opener, self._indexfile, changelog2, linkmapper
         )
 
 
@@ -174,7 +174,7 @@
         manifest.manifestrevlog.__init__(self, nodeconstants, opener)
         manifest2 = manifest.manifestrevlog(nodeconstants, opener2)
         unionrevlog.__init__(
-            self, opener, self._revlog.indexfile, manifest2, linkmapper
+            self, opener, self._revlog._indexfile, manifest2, linkmapper
         )
 
 
@@ -183,7 +183,7 @@
         filelog.filelog.__init__(self, opener, path)
         filelog2 = filelog.filelog(opener2, path)
         self._revlog = unionrevlog(
-            opener, self._revlog.indexfile, filelog2._revlog, linkmapper
+            opener, self._revlog._indexfile, filelog2._revlog, linkmapper
         )
         self._repo = repo
         self.repotiprev = self._revlog.repotiprev
diff --git a/mercurial/upgrade_utils/engine.py b/mercurial/upgrade_utils/engine.py
--- a/mercurial/upgrade_utils/engine.py
+++ b/mercurial/upgrade_utils/engine.py
@@ -80,12 +80,12 @@
 
     oldvfs = oldrl.opener
     newvfs = newrl.opener
-    oldindex = oldvfs.join(oldrl.indexfile)
-    newindex = newvfs.join(newrl.indexfile)
+    oldindex = oldvfs.join(oldrl._indexfile)
+    newindex = newvfs.join(newrl._indexfile)
     olddata = oldvfs.join(oldrl.datafile)
     newdata = newvfs.join(newrl.datafile)
 
-    with newvfs(newrl.indexfile, b'w'):
+    with newvfs(newrl._indexfile, b'w'):
         pass  # create all the directories
 
     util.copyfile(oldindex, newindex)
diff --git a/tests/test-contrib-perf.t b/tests/test-contrib-perf.t
--- a/tests/test-contrib-perf.t
+++ b/tests/test-contrib-perf.t
@@ -411,7 +411,7 @@
    >     from mercurial import (
    import newer module separately in try clause for early Mercurial
   contrib/perf.py:\d+: (re)
-   >     origindexpath = orig.opener.join(orig.indexfile)
+   >     origindexpath = orig.opener.join(indexfile)
    use getvfs()/getsvfs() for early Mercurial
   contrib/perf.py:\d+: (re)
    >     origdatapath = orig.opener.join(orig.datafile)
diff --git a/tests/test-revlog-raw.py b/tests/test-revlog-raw.py
--- a/tests/test-revlog-raw.py
+++ b/tests/test-revlog-raw.py
@@ -204,7 +204,7 @@
         flags = rlog.flags(r)
         ifh = dfh = None
         try:
-            ifh = dlog.opener(dlog.indexfile, b'a+')
+            ifh = dlog.opener(dlog._indexfile, b'a+')
             if not dlog._inline:
                 dfh = dlog.opener(dlog.datafile, b'a+')
             dlog._addrevision(