Enable notsup_compat_dir by default (#1970)

Few applications create the dir_$folder$ objects and users can enable
compat_dir if required.  This commit reduces readdir latency by 33%.
Also remove notsup_compat_dir from tests since these directories are
never created.  Fixes #927.  References #1643.

doc/man/s3fs.1.in

@@ -331,15 +331,13 @@ This name will be added to logging messages and user agent headers sent by s3fs.
 s3fs complements lack of information about file/directory mode if a file or a directory object does not have x-amz-meta-mode header.
 As default, s3fs does not complements stat information for a object, then the object will not be able to be allowed to list/modify.
 .TP
-\fB\-o\fR notsup_compat_dir (disable support of alternative directory names)
+\fB\-o\fR compat_dir (enable support of alternative directory names)
 .RS
-s3fs supports the three different naming schemas "dir/", "dir" and "dir_$folder$" to map directory names to S3 objects and vice versa. As a fourth variant, directories can be determined indirectly if there is a file object with a path (e.g. "/dir/file") but without the parent directory.
+s3fs supports two different naming schemas "dir/" and "dir" to map directory names to S3 objects and vice versa by default. As a third variant, directories can be determined indirectly if there is a file object with a path (e.g. "/dir/file") but without the parent directory.  This option enables a fourth variant, "dir_$folder$", created by older applications.
 .TP
 S3fs uses only the first schema "dir/" to create S3 objects for directories.
 .TP
 The support for these different naming schemas causes an increased communication effort.
-.TP
-If all applications exclusively use the "dir/" naming scheme and the bucket does not contain any objects with a different naming scheme, this option can be used to disable support for alternative naming schemes. This reduces access time and can save costs.
 .RE
 .TP
 \fB\-o\fR use_wtf8 - support arbitrary file system encoding.

src/s3fs.cpp

@@ -90,7 +90,7 @@ static off_t multipart_threshold  = 25 * 1024 * 1024;
 static int64_t singlepart_copy_limit = 512 * 1024 * 1024;
 static bool is_specified_endpoint = false;
 static int s3fs_init_deferred_exit_status = 0;
-static bool support_compat_dir    = true;// default supports compatibility directory type
+static bool support_compat_dir    = false;// default does not support compatibility directory type
 static int max_keys_list_object   = 1000;// default is 1000
 static off_t max_dirty_data       = 5LL * 1024LL * 1024LL * 1024LL;
 static bool use_wtf8              = false;
@@ -4164,9 +4164,15 @@ static int my_fuse_opt_proc(void* data, const char* arg, int key, struct fuse_ar
             return 0;
         }
         if(0 == strcmp(arg, "notsup_compat_dir")){
+            S3FS_PRN_WARN("notsup_compat_dir is enabled by default and a future version will remove this option.");
+
             support_compat_dir = false;
             return 0;
         }
+        if(0 == strcmp(arg, "compat_dir")){
+            support_compat_dir = true;
+            return 0;
+        }
         if(0 == strcmp(arg, "enable_content_md5")){
             S3fsCurl::SetContentMd5(true);
             return 0;

src/s3fs_help.cpp

@@ -412,23 +412,20 @@ static const char help_string[] =
     "        for a object, then the object will not be able to be allowed to\n"
     "        list/modify.\n"
     "\n"
-    "   notsup_compat_dir (disable support of alternative directory names)\n"
-    "        s3fs supports the three different naming schemas \"dir/\",\n"
-    "        \"dir\" and \"dir_$folder$\" to map directory names to S3\n"
-    "        objects and vice versa. As a fourth variant, directories can be\n"
+    "   compat_dir (enable support of alternative directory names)\n"
+    "        s3fs supports two different naming schemas \"dir/\" and\n"
+    "        \"dir\" to map directory names to S3 objects and\n"
+    "        vice versa by default. As a third variant, directories can be\n"
     "        determined indirectly if there is a file object with a path (e.g.\n"
     "        \"/dir/file\") but without the parent directory.\n"
+    "        This option enables a fourth variant, \"dir_$folder$\", created by\n"
+    "        older applications.\n"
     "        \n"
     "        S3fs uses only the first schema \"dir/\" to create S3 objects for\n"
     "        directories."
     "        \n"
     "        The support for these different naming schemas causes an increased\n"
     "        communication effort.\n"
-    "        \n"
-    "        If all applications exclusively use the \"dir/\" naming scheme and\n"
-    "        the bucket does not contain any objects with a different naming \n"
-    "        scheme, this option can be used to disable support for alternative\n"
-    "        naming schemes. This reduces access time and can save costs.\nq"
     "\n"
     "   use_wtf8 - support arbitrary file system encoding.\n"
     "        S3 requires all object names to be valid UTF-8. But some\n"

test/small-integration-test.sh

@@ -48,7 +48,6 @@ if [ -n "${ALL_TESTS}" ]; then
         "max_stat_cache_size=100"
         nocopyapi
         nomultipart
-        notsup_compat_dir
         sigv2
         sigv4
         "singlepart_copy_limit=10"  # limit size to exercise multipart code paths