[Libguestfs] [PATCH v2 1/2] mltools, options: support --allow-discards when decrypting LUKS devices

[Jan Synacek]

---
 mltools/tools_utils-c.c | 8 ++++----
 mltools/tools_utils.ml  | 6 +++---
 mltools/tools_utils.mli | 8 ++++++--
 options/decrypt.c       | 5 +++--
 options/inspect.c       | 2 +-
 options/options.h       | 2 +-
 6 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/mltools/tools_utils-c.c b/mltools/tools_utils-c.c
index 6c43b8d..1dcebc4 100644
--- a/mltools/tools_utils-c.c
+++ b/mltools/tools_utils-c.c
@@ -36,7 +36,7 @@
 
 #include "options.h"
 
-extern value guestfs_int_mllib_inspect_decrypt (value gv, value gpv, value keysv);
+extern value guestfs_int_mllib_inspect_decrypt (value gv, value gpv, value keysv, value allowdiscards);
 extern value guestfs_int_mllib_set_echo_keys (value unitv);
 extern value guestfs_int_mllib_set_keys_from_stdin (value unitv);
 extern value guestfs_int_mllib_rfc3339_date_time_string (value unitv);
@@ -46,9 +46,9 @@ int echo_keys = 0;
 int keys_from_stdin = 0;
 
 value
-guestfs_int_mllib_inspect_decrypt (value gv, value gpv, value keysv)
+guestfs_int_mllib_inspect_decrypt (value gv, value gpv, value keysv, value allowdiscards)
 {
-  CAMLparam3 (gv, gpv, keysv);
+  CAMLparam4 (gv, gpv, keysv, allowdiscards);
   CAMLlocal2 (elemv, v);
   guestfs_h *g = (guestfs_h *) (intptr_t) Int64_val (gpv);
   struct key_store *ks = NULL;
@@ -86,7 +86,7 @@ guestfs_int_mllib_inspect_decrypt (value gv, value gpv, value keysv)
     keysv = Field (keysv, 1);
   }
 
-  inspect_do_decrypt (g, ks);
+  inspect_do_decrypt (g, ks, Int_val (allowdiscards));
 
   CAMLreturn (Val_unit);
 }
diff --git a/mltools/tools_utils.ml b/mltools/tools_utils.ml
index 1271802..cb94125 100644
--- a/mltools/tools_utils.ml
+++ b/mltools/tools_utils.ml
@@ -29,7 +29,7 @@ and key_store_key =
   | KeyString of string
   | KeyFileName of string
 
-external c_inspect_decrypt : Guestfs.t -> int64 -> (string * key_store_key) list -> unit = "guestfs_int_mllib_inspect_decrypt"
+external c_inspect_decrypt : Guestfs.t -> int64 -> (string * key_store_key) list -> bool -> unit = "guestfs_int_mllib_inspect_decrypt"
 external c_set_echo_keys : unit -> unit = "guestfs_int_mllib_set_echo_keys" "noalloc"
 external c_set_keys_from_stdin : unit -> unit = "guestfs_int_mllib_set_keys_from_stdin" "noalloc"
 external c_rfc3339_date_time_string : unit -> string = "guestfs_int_mllib_rfc3339_date_time_string"
@@ -650,7 +650,7 @@ let is_btrfs_subvolume g fs =
     if g#last_errno () = Guestfs.Errno.errno_EINVAL then false
     else raise exn
 
-let inspect_decrypt g ks =
+let inspect_decrypt g ?(allow_discards = false) ks =
   (* Turn the keys in the key_store into a simpler struct, so it is possible
    * to read it using the C API.
    *)
@@ -664,7 +664,7 @@ let inspect_decrypt g ks =
    * function.
    *)
   c_inspect_decrypt g#ocaml_handle (Guestfs.c_pointer g#ocaml_handle)
-    keys_as_list
+    keys_as_list allow_discards
 
 let with_timeout op timeout ?(sleep = 2) fn =
   let start_t = Unix.gettimeofday () in
diff --git a/mltools/tools_utils.mli b/mltools/tools_utils.mli
index ab70f58..ac11a58 100644
--- a/mltools/tools_utils.mli
+++ b/mltools/tools_utils.mli
@@ -194,10 +194,14 @@ val inspect_mount_root_ro : Guestfs.guestfs -> string -> unit
 val is_btrfs_subvolume : Guestfs.guestfs -> string -> bool
 (** Checks if a filesystem is a btrfs subvolume. *)
 
-val inspect_decrypt : Guestfs.guestfs -> key_store -> unit
+val inspect_decrypt : Guestfs.guestfs -> ?allow_discards:bool -> key_store -> unit
 (** Simple implementation of decryption: look for any [crypto_LUKS]
     partitions and decrypt them, then rescan for VGs.  This only works
-    for Fedora whole-disk encryption. *)
+    for Fedora whole-disk encryption.
+
+    If [?allow_discards] is set, the underlying [crypto_LUKS] partitions
+    will be decrypted with the discard operation allowed, which allows
+    the partitions to be trimmed (and sparsified). Default is [false]. *)
 
 val with_timeout : string -> int -> ?sleep:int -> (unit -> 'a option) -> 'a
 (** [with_timeout op timeout ?sleep fn] implements a timeout loop.
diff --git a/options/decrypt.c b/options/decrypt.c
index 683cf5e..7e24254 100644
--- a/options/decrypt.c
+++ b/options/decrypt.c
@@ -71,7 +71,7 @@ make_mapname (const char *device, char *mapname, size_t len)
  * encryption schemes.
  */
 void
-inspect_do_decrypt (guestfs_h *g, struct key_store *ks)
+inspect_do_decrypt (guestfs_h *g, struct key_store *ks, bool allowdiscards)
 {
   CLEANUP_FREE_STRING_LIST char **partitions = guestfs_list_partitions (g);
   if (partitions == NULL)
@@ -101,7 +101,8 @@ inspect_do_decrypt (guestfs_h *g, struct key_store *ks)
          * is set?  This might break 'mount_ro'.
          */
         guestfs_push_error_handler (g, NULL, NULL);
-        r = guestfs_luks_open (g, partitions[i], keys[j], mapname);
+        r = guestfs_luks_open_opts (g, partitions[i], keys[j], mapname,
+                                    GUESTFS_LUKS_OPEN_OPTS_ALLOWDISCARDS, allowdiscards, -1);
         guestfs_pop_error_handler (g);
         if (r == 0)
           goto opened;
diff --git a/options/inspect.c b/options/inspect.c
index 3de6d70..be69419 100644
--- a/options/inspect.c
+++ b/options/inspect.c
@@ -70,7 +70,7 @@ inspect_mount_handle (guestfs_h *g, struct key_store *ks)
   if (live)
     error (EXIT_FAILURE, 0, _("don’t use --live and -i options together"));
 
-  inspect_do_decrypt (g, ks);
+  inspect_do_decrypt (g, ks, false);
 
   char **roots = guestfs_inspect_os (g);
   if (roots == NULL)
diff --git a/options/options.h b/options/options.h
index 9b78302..2467804 100644
--- a/options/options.h
+++ b/options/options.h
@@ -137,7 +137,7 @@ struct key_store {
 extern void parse_config (void);
 
 /* in decrypt.c */
-extern void inspect_do_decrypt (guestfs_h *g, struct key_store *ks);
+extern void inspect_do_decrypt (guestfs_h *g, struct key_store *ks, bool allowdiscards);
 
 /* in domain.c */
 extern int add_libvirt_drives (guestfs_h *g, const char *guest);
-- 
2.24.1