[Libguestfs] [PATCH 2/4] New API: resize2fs-size to allow shrinking ext2 filesystems (RHBZ#585221).

[Richard W.M. Jones]

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>From 71b02d6654395ff04689055f3820b3ad4e54ec00 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones at redhat.com>
Date: Fri, 21 May 2010 14:13:24 +0100
Subject: [PATCH 2/4] New API: resize2fs-size to allow shrinking ext2 filesystems (RHBZ#585221).

---
 daemon/ext2.c    |   36 ++++++++++++++++++++++++++++++++++++
 src/generator.ml |    7 +++++++
 2 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/daemon/ext2.c b/daemon/ext2.c
index 3758f4e..3a075e5 100644
--- a/daemon/ext2.c
+++ b/daemon/ext2.c
@@ -20,6 +20,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -301,6 +302,41 @@ do_resize2fs (const char *device)
 }
 
 int
+do_resize2fs_size (const char *device, int64_t size)
+{
+  char *err;
+  int r;
+
+  char prog[] = "resize2fs";
+  if (e2prog (prog) == -1)
+    return -1;
+
+  /* resize2fs itself may impose additional limits.  Since we are
+   * going to use the 'K' suffix however we can only work with whole
+   * kilobytes.
+   */
+  if (size & 1023) {
+    reply_with_error ("%" PRIi64 ": size must be a round number of kilobytes",
+                      size);
+    return -1;
+  }
+  size /= 1024;
+
+  char buf[32];
+  snprintf (buf, sizeof buf, "%" PRIi64 "K", size);
+
+  r = command (NULL, &err, prog, device, buf, NULL);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    free (err);
+    return -1;
+  }
+
+  free (err);
+  return 0;
+}
+
+int
 do_e2fsck_f (const char *device)
 {
   char *err;
diff --git a/src/generator.ml b/src/generator.ml
index aca56a8..b2ba513 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -4686,6 +4686,13 @@ unlikely for regular files in ordinary circumstances.
 
 See also C<guestfs_pread>.");
 
+  ("resize2fs_size", (RErr, [Device "device"; Int64 "size"]), 248, [],
+   [],
+   "resize an ext2/ext3 filesystem (with size)",
+   "\
+This command is the same as C<guestfs_resize2fs> except that it
+allows you to specify the new size (in bytes) explicitly.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
-- 
1.6.6.1