virt-rescue: Refresh documentation.

[libguestfs.git] / src / generator.ml

diff --git a/src/generator.ml b/src/generator.ml
index fc3dc34..68b25e0 100755 (executable)
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -953,8 +953,15 @@ exist.
 The mounted filesystem is writable, if we have sufficient permissions
 on the underlying device.
 
-The filesystem options C<sync> and C<noatime> are set with this
-call, in order to improve reliability.");
+B<Important note:>
+When you use this call, the filesystem options C<sync> and C<noatime>
+are set implicitly.  This was originally done because we thought it
+would improve reliability, but it turns out that I<-o sync> has a
+very large negative performance impact and negligible effect on
+reliability.  Therefore we recommend that you avoid using
+C<guestfs_mount> in any code that needs performance, and instead
+use C<guestfs_mount_options> (use an empty string for the first
+parameter if you don't want any options).");
 
   ("sync", (RErr, []), 2, [],
    [ InitEmpty, Always, TestRun [["sync"]]],
@@ -2079,7 +2086,11 @@ mounts the filesystem with the read-only (I<-o ro>) flag.");
    "\
 This is the same as the C<guestfs_mount> command, but it
 allows you to set the mount options as for the
-L<mount(8)> I<-o> flag.");
+L<mount(8)> I<-o> flag.
+
+If the C<options> parameter is an empty string, then
+no options are passed (all options default to whatever
+the filesystem uses).");
 
   ("mount_vfs", (RErr, [String "options"; String "vfstype"; Device "device"; String "mountpoint"]), 75, [],
    [],
@@ -3244,7 +3255,20 @@ for full details.");
 
   ("read_file", (RBufferOut "content", [Pathname "path"]), 150, [ProtocolLimitWarning],
    [InitISOFS, Always, TestOutputBuffer (
-      [["read_file"; "/known-4"]], "abc\ndef\nghi")],
+      [["read_file"; "/known-4"]], "abc\ndef\nghi");
+    (* Test various near large, large and too large files (RHBZ#589039). *)
+    InitBasicFS, Always, TestLastFail (
+      [["touch"; "/a"];
+       ["truncate_size"; "/a"; "4194303"]; (* GUESTFS_MESSAGE_MAX - 1 *)
+       ["read_file"; "/a"]]);
+    InitBasicFS, Always, TestLastFail (
+      [["touch"; "/a"];
+       ["truncate_size"; "/a"; "4194304"]; (* GUESTFS_MESSAGE_MAX *)
+       ["read_file"; "/a"]]);
+    InitBasicFS, Always, TestLastFail (
+      [["touch"; "/a"];
+       ["truncate_size"; "/a"; "41943040"]; (* GUESTFS_MESSAGE_MAX * 10 *)
+       ["read_file"; "/a"]])],
    "read a file",
    "\
 This calls returns the contents of the file C<path> as a
@@ -6552,6 +6576,8 @@ int main (int argc, char *argv[])
   iteri (
     fun i test_name ->
       pr "  test_num++;\n";
+      pr "  if (guestfs_get_verbose (g))\n";
+      pr "    printf (\"-------------------------------------------------------------------------------\\n\");\n";
       pr "  printf (\"%%3d/%%3d %s\\n\", test_num, nr_tests);\n" test_name;
       pr "  if (%s () == -1) {\n" test_name;
       pr "    printf (\"%s FAILED\\n\");\n" test_name;