[Libguestfs] mke2fs fails due to wipefs --force

[Richard W.M. Jones]

On Sun, Jan 19, 2014 at 07:42:58PM +0100, Olaf Hering wrote:
> My wipefs has no --force option, as a result mke2fs command in guestfish fails.
> 
> Looks like 72dd398679cd0bb803daf306d12558369615ba70 needs an adjustment
> to make use of do_wipefs?
> Also str_wipefs is not used in that file.

Also daemon/zero.c has a wipefs_has_force_option function.  It seems
like it would be better if this function was also used in
wipe_device_before_mkfs (in the same file).

But yes, it's definitely a bug if wipefs is causing mke2fs to fail.

How about the attached patch (only compile-tested)?

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Fedora Windows cross-compiler. Compile Windows programs, test, and
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-------------- next part --------------
>From c9b4e65b376b1c6c3f45e66f34c97bebe8412a02 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones at redhat.com>
Date: Sun, 19 Jan 2014 20:28:35 +0000
Subject: [PATCH] daemon: Use wipefs_has_force_option to decide whether to add
 wipefs --force option.

---
 daemon/zero.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/daemon/zero.c b/daemon/zero.c
index a07989e..ff0ea97 100644
--- a/daemon/zero.c
+++ b/daemon/zero.c
@@ -26,6 +26,8 @@
 #include <unistd.h>
 #include <sys/statvfs.h>
 
+#include "ignore-value.h"
+
 #include "daemon.h"
 #include "actions.h"
 #include "optgroups.h"
@@ -91,7 +93,7 @@ wipefs_has_force_option (void)
   CLEANUP_FREE char *out = NULL, *err = NULL;
 
   if (flag == -1) {
-    r = command (&out, &err, "wipefs", "--help", NULL);
+    r = command (&out, &err, str_wipefs, "--help", NULL);
     if (r == -1) {
       reply_with_error ("%s", err);
       return -1;
@@ -354,15 +356,23 @@ do_zero_free_space (const char *dir)
 void
 wipe_device_before_mkfs (const char *device)
 {
-  int r;
+  int force;
+  const size_t MAX_ARGS = 16;
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
 
-  r = command (NULL, NULL, "wipefs", "-a", "--force", device, NULL);
-  if (r == 0)
+  force = wipefs_has_force_option ();
+  if (force == -1)
     return;
 
-  r = command (NULL, NULL, "wipefs", "-a", device, NULL);
-  if (r == 0)
-    return;
+  ADD_ARG (argv, i, str_wipefs);
+  ADD_ARG (argv, i, "-a");
+  if (force)
+    ADD_ARG (argv, i, "--force");
+  ADD_ARG (argv, i, device);
+  ADD_ARG (argv, i, NULL);
+
+  ignore_value (commandv (NULL, NULL, argv));
 
   /* XXX We could fall back to overwriting bits of disk here, but if
    * they don't have working wipefs, it seems unlikely they are using
-- 
1.8.4.2