Merge branch 'bd/maint-unpack-trees-parawalk-fix' into maint

* bd/maint-unpack-trees-parawalk-fix:
  unpack-trees: Make index lookahead less pessimal

diff --combined unpack-trees.c
index 490cd5f6f4779cbff68405722b98e522cbeb3cde,fe2340892a0d0b772d9616fc33e034faa99824f8..e8f03f51541472ead12d55672ba4422f97a3c113
--- 1/unpack-trees.c
--- 2/unpack-trees.c
+++ b/unpack-trees.c
@@@ -67,8 -67,16 +67,8 @@@ static void unlink_entry(struct cache_e
  {
        if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
                return;
 -      if (S_ISGITLINK(ce->ce_mode)) {
 -              if (rmdir(ce->name)) {
 -                      warning("unable to rmdir %s: %s",
 -                              ce->name, strerror(errno));
 -                      return;
 -              }
 -      }
 -      else
 -              if (unlink_or_warn(ce->name))
 -                      return;
 +      if (remove_or_warn(ce->ce_mode, ce->name))
 +              return;
        schedule_dir_for_removal(ce->name, ce_namelen(ce));
  }
  
@@@ -520,9 -528,17 +520,17 @@@ static int find_cache_pos(struct traver
                const char *ce_name, *ce_slash;
                int cmp, ce_len;
  
-               if (!ce_in_traverse_path(ce, info))
+               if (ce->ce_flags & CE_UNPACKED) {
+                       /*
+                        * cache_bottom entry is already unpacked, so
+                        * we can never match it; don't check it
+                        * again.
+                        */
+                       if (pos == o->cache_bottom)
+                               ++o->cache_bottom;
                        continue;
-               if (ce->ce_flags & CE_UNPACKED)
+               }
+               if (!ce_in_traverse_path(ce, info))
                        continue;
                ce_name = ce->name + pfxlen;
                ce_slash = strchr(ce_name, '/');
@@@ -854,7 -870,7 +862,7 @@@ static int verify_uptodate_1(struct cac
  {
        struct stat st;
  
 -      if (o->index_only || (!ce_skip_worktree(ce) && (o->reset || ce_uptodate(ce))))
 +      if (o->index_only || (!((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce)) && (o->reset || ce_uptodate(ce))))
                return 0;
  
        if (!lstat(ce->name, &st)) {