In guestfs-tools commit 4fe8a03cd2d3 ('sysprep: remove lvm2's default
"system.devices" file', 2022-04-11), we disabled the use of LVM2's new
"devicesfile" feature, which could interfere with the cloning of virtual
machines.
We suspected in
https://bugzilla.redhat.com/show_bug.cgi?id=2072493#c6
that the same lvm2 feature could affect the libguestfs appliance itself,
but decided in
https://bugzilla.redhat.com/show_bug.cgi?id=2072493#c8
https://bugzilla.redhat.com/show_bug.cgi?id=2072493#c10
that this would not be the case, because "appliance/init" already
constructed a pristine LVM_SYSTEM_DIR.
Unfortunately, that's not enough: due to the "use_devicesfile=1" default
(on RHEL9 anyway), some "lvm" invocation, possibly inside the
lvm-set-filter API, *creates* "$LVM_SYSTEM_DIR/devices/system.devices".
And then we get (minimally) warnings such as
Please remove the lvm.conf global_filter, it is ignored with the
devices
file.
Please remove the lvm.conf filter, it is ignored with the devices file.
when using the lvm-set-filter API.
Explicitly disable the "devices file" in "appliance/init", and also
whenever we rewrite "lvm.conf" -- that is, in set_filter()
[daemon/lvm-filter.c]. In the former, check for the feature by locating
the devicesfile-related utilities "lvmdevices" and "vgimportdevices".
In
the C code, invoke the utilities with the "--help" option instead. (In
"appliance/init", I thought it was best not to call any lvm2 utilities
even with "--help", with our lvm2.conf still under construction there.) If
either utility is available, set "use_devicesfile = 0".
Cc: David Teigland <teigland(a)redhat.com>
Bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=1965941
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
Notes:
Tested:
- on top of "master" (7afbf5ee4415), using a Fedora 35 host, where the
lvm2 packages copied into the appliance do not have the "devicesfile"
feature (-> regression test);
- on top of "rhel-9.1" (ad24b9f4d695), in the form of a Brew scratch
build, using a nightly RHEL-9.1 install, where the lvm2 packages
copied into the appliance have the "devicesfile" feature (-> bugfix
test).
daemon/lvm-filter.c | 19 +++++++++++++++++++
appliance/init | 11 +++++++++++
2 files changed, 30 insertions(+)
diff --git a/daemon/lvm-filter.c b/daemon/lvm-filter.c
index c6dd35156d37..f75e2198831e 100644
--- a/daemon/lvm-filter.c
+++ b/daemon/lvm-filter.c
@@ -68,6 +68,18 @@ free_lvm_system_dir (void)
free (lvm_system_dir);
}
+static bool devicesfile_feature (void)
+{
+ static bool checked, available;
+
+ if (!checked) {
+ checked = true;
+ available = command (NULL, NULL, "lvmdevices", "--help", NULL) ==
0 ||
+ command (NULL, NULL, "vgimportdevices", "--help",
NULL) == 0;
+ }
+ return available;
+}
+
/* Rewrite the 'filter = [ ... ]' line in lvm.conf. */
static int
set_filter (char *const *filters)
@@ -88,6 +100,13 @@ set_filter (char *const *filters)
}
fprintf (fp, "devices {\n");
+
+ /* If lvm2 supports a "devices file", we need to disable its use
+ * (RHBZ#1965941).
+ */
+ if (devicesfile_feature ())
+ fprintf (fp, " use_devicesfile = 0\n");
+
for (j = 0; filter_types[j] != NULL; ++j) {
fprintf (fp, " %s = [\n", filter_types[j]);
fprintf (fp, " ");
diff --git a/appliance/init b/appliance/init
index 7076821d2250..19aa151b73aa 100755
--- a/appliance/init
+++ b/appliance/init
@@ -134,6 +134,17 @@ mdadm -As --auto=yes --no-degraded
# Empty LVM configuration file means "all defaults".
mkdir -p /tmp/lvm
touch /tmp/lvm/lvm.conf
+
+# If lvm2 supports a "devices file", we need to disable its use
+# (RHBZ#1965941).
+if command -v lvmdevices || command -v vgimportdevices; then
+ {
+ printf 'devices {\n'
+ printf '\tuse_devicesfile = 0\n'
+ printf '}\n'
+ } >> /tmp/lvm/lvm.conf
+fi
+
LVM_SYSTEM_DIR=/tmp/lvm
export LVM_SYSTEM_DIR
lvmetad
base-commit: 7afbf5ee4415f6fa2553898d3af238e794062096
--
2.19.1.3.g30247aa5d201