From 3ad6840403edac13249d373d29c7d1f72b35c8b0 Mon Sep 17 00:00:00 2001

From: "Richard W.M. Jones" <rjones@redhat.com>

Date: Thu, 24 May 2018 10:24:25 +0100

Subject: [PATCH] daemon: Move lvmetad to early in the appliance boot process.

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When the daemon starts up it creates a fresh (empty) LVM configuration

and starts up lvmetad (which depends on the LVM configuration).

However this appears to cause problems: Some types of PV seem to

require lvmetad and don't work without it

(https://bugzilla.redhat.com/show_bug.cgi?id=1581810).  If we don't

start lvmetad earlier, the device nodes are not created.

Therefore move the whole initialization step into appliance/init.

Two further changes had to be made:

Now we are using lvmetad all the time, using vgchange is incorrect.

With lvmetad activated early we must use ‘pvscan --cache --activate ay’

to scan all disks for PVs and activate any VGs on them (although the

documentation is complex, confusing and contradictory so I'm not

completely sure about this).

The ‘lvm_system_dir’ local variable in ‘daemon/lvm-filter.c’

previously contained the path of the directory above $LVM_SYSTEM_DIR

(eg. $LVM_SYSTEM_DIR = "/etc/lvm", lvm_system_dir = "/etc").  As this

was highly confusing, I have changed it so the local variable and the

environment variable have identical contents.  This involved removing

the ‘lvm/’ component from a couple of paths since it is now included

in the local variable.

(cherry picked from commit dd162d2cd56a2ecf4bcd40a7f463940eaac875b8)

---

 appliance/init      | 11 +++++-

 daemon/daemon.h     |  4 ---

 daemon/guestfsd.c   |  8 -----

 daemon/lvm-filter.c | 81 +++++++++++++--------------------------------

 4 files changed, 33 insertions(+), 71 deletions(-)

diff --git a/appliance/init b/appliance/init

index 1cd264e08..471d83cae 100755

--- a/appliance/init

+++ b/appliance/init

@@ -130,9 +130,17 @@ echo nameserver 169.254.2.3 > /etc/resolv.conf

 # Scan for MDs but don't run arrays unless all expected drives are present

 mdadm -As --auto=yes --no-degraded

+# Set up a clean LVM environment.

+# Empty LVM configuration file means "all defaults".

+mkdir -p /tmp/lvm

+touch /tmp/lvm/lvm.conf

+LVM_SYSTEM_DIR=/tmp/lvm

+export LVM_SYSTEM_DIR

+lvmetad

+

 # Scan for LVM.

 modprobe dm_mod ||:

-lvm vgchange -aay --sysinit

+lvm pvscan --cache --activate ay

 # Scan for MDs and run all found arrays even they are in degraded state

 mdadm -As --auto=yes --run

@@ -146,6 +154,7 @@ if test "$guestfs_verbose" = 1 && test "$guestfs_boot_analysis" != 1; then

     ls -lR /dev

     cat /proc/mounts

     cat /proc/mdstat

+    lvm config

     lvm pvs

     lvm vgs

     lvm lvs

diff --git a/daemon/daemon.h b/daemon/daemon.h

index 7958ba781..faaf1237e 100644

--- a/daemon/daemon.h

+++ b/daemon/daemon.h

@@ -249,10 +249,6 @@ extern char *get_blkid_tag (const char *device, const char *tag);

 /* lvm.c */

 extern int lv_canonical (const char *device, char **ret);

-/* lvm-filter.c */

-extern void clean_lvm_config (void);

-extern void start_lvmetad (void);

-

 /* zero.c */

 extern void wipe_device_before_mkfs (const char *device);

diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c

index 68d3de2ec..ae428e573 100644

--- a/daemon/guestfsd.c

+++ b/daemon/guestfsd.c

@@ -233,14 +233,6 @@ main (int argc, char *argv[])

   _umask (0);

 #endif

-  /* Make a private copy of /etc/lvm so we can change the config (see

-   * daemon/lvm-filter.c).

-   */

-  if (!test_mode) {

-    clean_lvm_config ();

-    start_lvmetad ();

-  }

-

   /* Connect to virtio-serial channel. */

   if (!channel)

     channel = VIRTIO_SERIAL_CHANNEL;

diff --git a/daemon/lvm-filter.c b/daemon/lvm-filter.c

index ad85a7cc4..9d877c104 100644

--- a/daemon/lvm-filter.c

+++ b/daemon/lvm-filter.c

@@ -36,71 +36,36 @@

 #include "daemon.h"

 #include "actions.h"

-/* This runs during daemon start up and creates a fresh LVM

- * configuration which we can modify as we desire.  LVM allows

- * configuration to be completely empty (meaning "all defaults").

- *

- * The final directory layout is:

- *

- *   /tmp/lvmXXXXXX                 (lvm_system_dir set to this)

- *   /tmp/lvmXXXXXX/lvm             ($LVM_SYSTEM_DIR set to this)

- *   /tmp/lvmXXXXXX/lvm/lvm.conf    (configuration file - initially empty)

- */

-static char lvm_system_dir[] = "/tmp/lvmXXXXXX";

-

-static void rm_lvm_system_dir (void);

 static void debug_lvm_config (void);

-void

-clean_lvm_config (void)

-{

-  char env[64], conf[64];

-  FILE *fp;

-

-  if (mkdtemp (lvm_system_dir) == NULL)

-    error (EXIT_FAILURE, errno, "mkdtemp: %s", lvm_system_dir);

-

-  snprintf (env, sizeof env, "%s/lvm", lvm_system_dir);

-  mkdir (env, 0755);

-  snprintf (conf, sizeof conf, "%s/lvm/lvm.conf", lvm_system_dir);

-  fp = fopen (conf, "w");

-  if (fp == NULL) {

-    perror ("clean_lvm_config: cannot create empty lvm.conf");

-    exit (EXIT_FAILURE);

-  }

-  fclose (fp);

-

-  /* Set environment variable so we use the clean configuration. */

-  setenv ("LVM_SYSTEM_DIR", env, 1);

-

-  /* Set a handler to remove the temporary directory at exit. */

-  atexit (rm_lvm_system_dir);

+/* Read LVM_SYSTEM_DIR environment variable, or set it to a default

+ * value if the environment variable is not set.

+ */

+static char *lvm_system_dir;

+static void get_lvm_system_dir (void) __attribute__((constructor));

+static void free_lvm_system_dir (void) __attribute__((destructor));

-  debug_lvm_config ();

-}

-

-/* Try to run lvmetad, without failing if it couldn't. */

-void

-start_lvmetad (void)

+static void

+get_lvm_system_dir (void)

 {

-  int r;

+  const char *p;

-  if (verbose)

-    printf ("%s\n", "lvmetad");

-  r = system ("lvmetad");

-  if (r == -1)

-    perror ("system/lvmetad");

-  else if (!WIFEXITED (r) || WEXITSTATUS (r) != 0)

-    fprintf (stderr, "warning: lvmetad command failed\n");

+  p = getenv ("LVM_SYSTEM_DIR");

+  if (p) {

+    lvm_system_dir = strdup (p);

+    if (lvm_system_dir == NULL) abort ();

+  }

+  if (!lvm_system_dir) {

+    lvm_system_dir = strdup ("/etc/lvm");

+    if (lvm_system_dir == NULL) abort ();

+  }

+  fprintf (stderr, "lvm_system_dir = %s\n", lvm_system_dir);

 }

 static void

-rm_lvm_system_dir (void)

+free_lvm_system_dir (void)

 {

-  char cmd[64];

-

-  snprintf (cmd, sizeof cmd, "rm -rf %s", lvm_system_dir);

-  ignore_value (system (cmd));

+  free (lvm_system_dir);

 }

 /* Rewrite the 'filter = [ ... ]' line in lvm.conf. */

@@ -112,7 +77,7 @@ set_filter (char *const *filters)

   FILE *fp;

   size_t i, j;

-  if (asprintf (&conf, "%s/lvm/lvm.conf", lvm_system_dir) == -1) {

+  if (asprintf (&conf, "%s/lvm.conf", lvm_system_dir) == -1) {

     reply_with_perror ("asprintf");

     return -1;

   }

@@ -177,7 +142,7 @@ static int

 rescan (void)

 {

   char lvm_cache[64];

-  snprintf (lvm_cache, sizeof lvm_cache, "%s/lvm/cache/.cache", lvm_system_dir);

+  snprintf (lvm_cache, sizeof lvm_cache, "%s/cache/.cache", lvm_system_dir);

   unlink (lvm_cache);

-- 

2.17.1