New API: fstrim - allow filesystem trim.

daemon/Makefile.am

@@ -114,6 +114,7 @@ guestfsd_SOURCES = \
 	fill.c \
 	find.c \
 	fsck.c \
+	fstrim.c \
 	glob.c \
 	grep.c \
 	grub.c \

daemon/fstrim.c

@@ -0,0 +1,97 @@
+/* libguestfs - the guestfsd daemon
+ * Copyright (C) 2012 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "guestfs_protocol.h"
+#include "daemon.h"
+#include "actions.h"
+#include "optgroups.h"
+
+#define MAX_ARGS 64
+
+int
+optgroup_fstrim_available (void)
+{
+  return prog_exists ("fstrim");
+}
+
+/* Takes optional arguments, consult optargs_bitmask. */
+int
+do_fstrim (const char *path,
+           int64_t offset, int64_t length, int64_t minimumfreeextent)
+{
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
+  char offset_s[64], length_s[64], mfe_s[64];
+  char *err;
+  int r;
+
+  ADD_ARG (argv, i, "fstrim");
+
+  if ((optargs_bitmask & GUESTFS_FSTRIM_OFFSET_BITMASK)) {
+    if (offset < 0) {
+      reply_with_error ("offset < 0");
+      return -1;
+    }
+
+    snprintf (offset_s, sizeof offset_s, "%" PRIi64, offset);
+    ADD_ARG (argv, i, "-o");
+    ADD_ARG (argv, i, offset_s);
+  }
+
+  if ((optargs_bitmask & GUESTFS_FSTRIM_LENGTH_BITMASK)) {
+    if (length <= 0) {
+      reply_with_error ("length <= 0");
+      return -1;
+    }
+
+    snprintf (length_s, sizeof length_s, "%" PRIi64, length);
+    ADD_ARG (argv, i, "-l");
+    ADD_ARG (argv, i, length_s);
+  }
+
+  if ((optargs_bitmask & GUESTFS_FSTRIM_MINIMUMFREEEXTENT_BITMASK)) {
+    if (minimumfreeextent <= 0) {
+      reply_with_error ("minimumfreeextent <= 0");
+      return -1;
+    }
+
+    snprintf (mfe_s, sizeof mfe_s, "%" PRIi64, minimumfreeextent);
+    ADD_ARG (argv, i, "-m");
+    ADD_ARG (argv, i, mfe_s);
+  }
+
+  ADD_ARG (argv, i, path);
+  ADD_ARG (argv, i, NULL);
+
+  r = commandv (NULL, &err, argv);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    free (err);
+    return -1;
+  }
+  free (err);
+
+  return 0;
+}

generator/generator_actions.ml

@@ -6821,8 +6821,9 @@ The filesystem must be mounted read-write.
 The filesystem contents are not affected, but any free space
 in the filesystem is freed.
 
-In future (but not currently) these zeroed blocks will be
-\"sparsified\" - that is, given back to the host.");
+Free space is not \"trimmed\".  You may want to call
+C<guestfs_fstrim> either as an alternative to this,
+or after calling this, depending on your requirements.");
 
   ("lvcreate_free", (RErr, [String "logvol"; String "volgroup"; Int "percent"], []), 312, [Optional "lvm2"],
    [InitEmpty, Always, TestOutputList (
@@ -7259,6 +7260,28 @@ a later version of the filesystem, or having incompatible features.
 
 See also C<guestfs_available>, L<guestfs(3)/AVAILABILITY>.");
 
+  ("fstrim", (RErr, [Pathname "mountpoint"], [OInt64 "offset"; OInt64 "length"; OInt64 "minimumfreeextent"]), 334, [Optional "fstrim"],
+   [],
+   "trim free space in a filesystem",
+   "\
+Trim the free space in the filesystem mounted on C<mountpoint>.
+The filesystem must be mounted read-write.
+
+The filesystem contents are not affected, but any free space
+in the filesystem is \"trimmed\", that is, given back to the host
+device, thus making disk images more sparse, allowing unused space
+in qcow2 files to be reused, etc.
+
+This operation requires support in libguestfs, the mounted
+filesystem, the host filesystem, qemu and the host kernel.
+If this support isn't present it may give an error or even
+appear to run but do nothing.
+
+See also C<guestfs_zero_free_space>.  That is a slightly
+different operation that turns free space in the filesystem
+into zeroes.  It is valid to call C<guestfs_fstrim> either
+instead of, or after calling C<guestfs_zero_free_space>.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions

gobject/Makefile.inc

@@ -61,7 +61,8 @@ guestfs_gobject_headers= \
   include/guestfs-gobject/optargs-ntfsclone_out.h \
   include/guestfs-gobject/optargs-mkfs_btrfs.h \
   include/guestfs-gobject/optargs-set_e2attrs.h \
-  include/guestfs-gobject/optargs-btrfs_fsck.h
+  include/guestfs-gobject/optargs-btrfs_fsck.h \
+  include/guestfs-gobject/optargs-fstrim.h
 
 guestfs_gobject_sources= \
   src/session.c \
@@ -104,4 +105,5 @@ guestfs_gobject_sources= \
   src/optargs-ntfsclone_out.c \
   src/optargs-mkfs_btrfs.c \
   src/optargs-set_e2attrs.c \
-  src/optargs-btrfs_fsck.c
+  src/optargs-btrfs_fsck.c \
+  src/optargs-fstrim.c

po/POTFILES

@@ -34,6 +34,7 @@ daemon/fill.c
 daemon/find.c
 daemon/findfs.c
 daemon/fsck.c
+daemon/fstrim.c
 daemon/glob.c
 daemon/grep.c
 daemon/grub.c
@@ -142,6 +143,7 @@ gobject/src/optargs-copy_device_to_file.c
 gobject/src/optargs-copy_file_to_device.c
 gobject/src/optargs-copy_file_to_file.c
 gobject/src/optargs-e2fsck.c
+gobject/src/optargs-fstrim.c
 gobject/src/optargs-inspect_get_icon.c
 gobject/src/optargs-md_create.c
 gobject/src/optargs-mkfs_btrfs.c

src/MAX_PROC_NR

@@ -1 +1 @@
-333
+334