X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=generator%2Fgenerator_actions.ml;h=489631128e7aedeb5604b3343e86a05d4a803110;hb=5a9c59108c742170bc07b0a2ae15b51129b3ea44;hp=ccfecdddcc34f2e467507ff75f9d6fbe2b7ce901;hpb=4509ae44d818d49c8dd0c25c92c13d70b4f1de59;p=libguestfs.git

diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index ccfecdd..4896311 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -3006,10 +3006,14 @@ How many blocks are zeroed isn't specified (but it's I<not> enough
 to securely wipe the device).  It should be sufficient to remove
 any partition tables, filesystem superblocks and so on.
 
+If blocks are already zero, then this command avoids writing
+zeroes.  This prevents the underlying device from becoming non-sparse
+or growing unnecessarily.
+
 See also: C<guestfs_zero_device>, C<guestfs_scrub_device>,
 C<guestfs_is_zero_device>");
 
-  ("grub_install", (RErr, [Pathname "root"; Device "device"], []), 86, [],
+  ("grub_install", (RErr, [Pathname "root"; Device "device"], []), 86, [Optional "grub"],
    (* See:
     * https://bugzilla.redhat.com/show_bug.cgi?id=484986
     * https://bugzilla.redhat.com/show_bug.cgi?id=479760
@@ -3019,12 +3023,32 @@ C<guestfs_is_zero_device>");
        ["write"; "/boot/grub/device.map"; "(hd0) /dev/vda"];
        ["grub_install"; "/"; "/dev/vda"];
        ["is_dir"; "/boot"]])],
-   "install GRUB",
+   "install GRUB 1",
    "\
-This command installs GRUB (the Grand Unified Bootloader) on
+This command installs GRUB 1 (the Grand Unified Bootloader) on
 C<device>, with the root directory being C<root>.
 
-Note: If grub-install reports the error
+Notes:
+
+=over 4
+
+=item *
+
+There is currently no way in the API to install grub2, which
+is used by most modern Linux guests.  It is possible to run
+the grub2 command from the guest, although see the
+caveats in L<guestfs(3)/RUNNING COMMANDS>.
+
+=item *
+
+This uses C<grub-install> from the host.  Unfortunately grub is
+not always compatible with itself, so this only works in rather
+narrow circumstances.  Careful testing with each guest version
+is advisable.
+
+=item *
+
+If grub-install reports the error
 \"No suitable drive was found in the generated device map.\"
 it may be that you need to create a C</boot/grub/device.map>
 file first that contains the mapping between grub device names
@@ -3033,7 +3057,9 @@ a file containing:
 
  (hd0) /dev/vda
 
-replacing C</dev/vda> with the name of the installation device.");
+replacing C</dev/vda> with the name of the installation device.
+
+=back");
 
   ("cp", (RErr, [Pathname "src"; Pathname "dest"], []), 87, [],
    [InitScratchFS, Always, TestOutput (
@@ -5229,7 +5255,11 @@ is not large enough.");
    "\
 This command writes zeroes over the entire C<device>.  Compare
 with C<guestfs_zero> which just zeroes the first few blocks of
-a device.");
+a device.
+
+If blocks are already zero, then this command avoids writing
+zeroes.  This prevents the underlying device from becoming non-sparse
+or growing unnecessarily.");
 
   ("txz_in", (RErr, [FileIn "tarball"; Pathname "directory"], []), 229, [Optional "xz"],
    [InitScratchFS, Always, TestOutput (