Workaround another race condition issue

See https://bugzilla.redhat.com/show_bug.cgi?id=921706

src/fccache.c

@@ -545,6 +545,26 @@ FcCacheTimeValid (FcCache *cache, struct stat *dir_stat)
     return cache->checksum == (int) dir_stat->st_mtime;
 }
 
+static FcBool
+FcCacheDirsValid (FcCache *cache)
+{
+    FcStrSet *dirs = FcStrSetCreate ();
+    FcBool ret = FcFalse;
+
+    if (!dirs)
+	goto bail;
+    if (!FcDirScanOnly (dirs, FcCacheDir (cache)))
+	goto bail1;
+    ret = cache->dirs_count == dirs->num;
+    if (FcDebug () & FC_DBG_CACHE)
+	printf ("%s: cache: %d, fs: %d\n", FcCacheDir (cache), cache->dirs_count, dirs->num);
+
+bail1:
+    FcStrSetDestroy (dirs);
+bail:
+    return ret;
+}
+
 /*
  * Map a cache file into memory
  */
@@ -559,7 +579,8 @@ FcDirCacheMapFd (int fd, struct stat *fd_stat, struct stat *dir_stat)
     cache = FcCacheFindByStat (fd_stat);
     if (cache)
     {
-	if (FcCacheTimeValid (cache, dir_stat))
+	if (FcCacheTimeValid (cache, dir_stat) &&
+	    FcCacheDirsValid (cache))
 	    return cache;
 	FcDirCacheUnload (cache);
 	cache = NULL;
@@ -611,6 +632,7 @@ FcDirCacheMapFd (int fd, struct stat *fd_stat, struct stat *dir_stat)
 	cache->version < FC_CACHE_CONTENT_VERSION ||
 	cache->size != (intptr_t) fd_stat->st_size ||
 	!FcCacheTimeValid (cache, dir_stat) ||
+	!FcCacheDirsValid (cache) ||
 	!FcCacheInsert (cache, fd_stat))
     {
 	if (allocated)

src/fcdir.c

@@ -164,7 +164,8 @@ FcDirScanConfig (FcFontSet	*set,
 		 FcBlanks	*blanks,
 		 const FcChar8	*dir,
 		 FcBool		force, /* XXX unused */
-		 FcConfig	*config)
+		 FcConfig	*config,
+		 FcBool		scanOnly)
 {
     DIR			*d;
     struct dirent	*e;
@@ -180,7 +181,7 @@ FcDirScanConfig (FcFontSet	*set,
     if (!set && !dirs)
 	return FcTrue;
 
-    if (!blanks)
+    if (!blanks && !scanOnly)
 	blanks = FcConfigGetBlanks (config);
 
     /* freed below */
@@ -233,7 +234,17 @@ FcDirScanConfig (FcFontSet	*set,
      * Scan file files to build font patterns
      */
     for (i = 0; i < files->num; i++)
-	FcFileScanConfig (set, dirs, blanks, files->strs[i], config);
+    {
+	if (scanOnly)
+	{
+	    if (FcFileIsDir (files->strs[i]))
+		FcStrSetAdd (dirs, files->strs[i]);
+	}
+	else
+	{
+	    FcFileScanConfig (set, dirs, blanks, files->strs[i], config);
+	}
+    }
 
 bail2:
     FcStrSetDestroy (files);
@@ -257,7 +268,14 @@ FcDirScan (FcFontSet	    *set,
     if (cache || !force)
 	return FcFalse;
 
-    return FcDirScanConfig (set, dirs, blanks, dir, force, FcConfigGetCurrent ());
+    return FcDirScanConfig (set, dirs, blanks, dir, force, FcConfigGetCurrent (), FcFalse);
+}
+
+FcBool
+FcDirScanOnly (FcStrSet		*dirs,
+	       const FcChar8	*dir)
+{
+    return FcDirScanConfig (NULL, dirs, NULL, dir, FcTrue, NULL, FcTrue);
 }
 
 /*
@@ -288,7 +306,7 @@ FcDirCacheScan (const FcChar8 *dir, FcConfig *config)
     /*
      * Scan the dir
      */
-    if (!FcDirScanConfig (set, dirs, NULL, dir, FcTrue, config))
+    if (!FcDirScanConfig (set, dirs, NULL, dir, FcTrue, config, FcFalse))
 	goto bail2;
 
     /*
@@ -330,7 +348,7 @@ FcDirCacheRescan (const FcChar8 *dir, FcConfig *config)
     /*
      * Scan the dir
      */
-    if (!FcDirScanConfig (NULL, dirs, NULL, dir, FcTrue, config))
+    if (!FcDirScanConfig (NULL, dirs, NULL, dir, FcTrue, config, FcFalse))
 	goto bail1;
     /*
      * Rebuild the cache object

src/fcint.h

@@ -849,7 +849,12 @@ FcDirScanConfig (FcFontSet	*set,
 		 FcBlanks	*blanks,
 		 const FcChar8	*dir,
 		 FcBool		force,
-		 FcConfig	*config);
+		 FcConfig	*config,
+		 FcBool		scanOnly);
+
+FcPrivate FcBool
+FcDirScanOnly (FcStrSet		*dirs,
+	       const FcChar8	*dir);
 
 /* fcfont.c */
 FcPrivate int