From: Richard W.M. Jones <rjones@redhat.com>
Date: Wed, 20 Jul 2011 13:41:39 +0000 (+0100)
Subject: blkid: Use -c /dev/null option to kill the cache.
X-Git-Tag: 1.8.10~9
X-Git-Url: http://git.annexia.org/?a=commitdiff_plain;h=880374c6df2a694bb1457231f110d9ef7035e5b7;p=libguestfs.git

blkid: Use -c /dev/null option to kill the cache.

On recent Debian, /etc/blkid.tab is now a symlink to /dev/.blkid.tab.
Rather than chasing the cache file around (it may move to /run in future)
use the -c /dev/null option to stop blkid from reading the cache.
(cherry picked from commit 1d0f398d8e3c74ce6a70cbbb8d9b8ae07c6d7ef6)
---

diff --git a/daemon/blkid.c b/daemon/blkid.c
index f631061..7935ac3 100644
--- a/daemon/blkid.c
+++ b/daemon/blkid.c
@@ -33,16 +33,11 @@ get_blkid_tag (const char *device, const char *tag)
   char *out, *err;
   int r;
 
-  /* Kill the cache file, forcing blkid to reread values from the
-   * original filesystems.  In blkid there is a '-p' option which is
-   * supposed to do this, but (a) it doesn't work and (b) that option
-   * is not supported in RHEL 5.
-   */
-  unlink ("/etc/blkid/blkid.tab"); /* Red Hat, Fedora */
-  unlink ("/etc/blkid.tab"); /* Debian */
-
   r = commandr (&out, &err,
-                "blkid", "-o", "value", "-s", tag, device, NULL);
+                "blkid",
+                /* Adding -c option kills all caching, even on RHEL 5. */
+                "-c", "/dev/null",
+                "-o", "value", "-s", tag, device, NULL);
   if (r != 0 && r != 2) {
     if (r >= 0)
       reply_with_error ("%s: %s (blkid returned %d)", device, err, r);