From 20eb220c0b1c8a7aaaadcc26fe5fdeae681341b4 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Mon, 30 May 2022 16:10:27 +0200 Subject: [PATCH] appliance, daemon: disable lvm2 devicesfile 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 Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1965941 Signed-off-by: Laszlo Ersek Message-Id: <20220530141027.16167-1-lersek@redhat.com> Acked-by: Richard W.M. Jones [lersek@redhat.com: style fix: break "devicesfile_feature" in the function definition to a new line] (cherry picked from commit 8fc4d167153a23ab91befafb2f7083db2d312ef8) --- appliance/init | 11 +++++++++++ daemon/lvm-filter.c | 20 ++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/appliance/init b/appliance/init index fe6497b4d..e67d88280 100755 --- a/appliance/init +++ b/appliance/init @@ -142,6 +142,17 @@ 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 diff --git a/daemon/lvm-filter.c b/daemon/lvm-filter.c index c6dd35156..00b36f826 100644 --- a/daemon/lvm-filter.c +++ b/daemon/lvm-filter.c @@ -68,6 +68,19 @@ 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 +101,13 @@ 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, " "); -- 2.31.1