Add activation/udev_sync to lvm.conf.

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.51 - 
 ================================
+  Add activation/udev_sync to lvm.conf.
   Only change LV symlinks on ACTIVATE not PRELOAD.
   Make lvconvert honour log mirror options combined with downconversion.
   Allow LV suspend while --ignorelockingfailure is in force.

doc/example.conf

@@ -301,6 +301,16 @@ global {
 }
 
 activation {
+    # Set to 0 to disable udev syncronisation (if compiled into the binaries).
+    # Processes will not wait for notification from udev.
+    # They will continue irrespective of any possible udev processing
+    # in the background.  You should only use this if udev is not running
+    # or has rules that ignore the devices LVM2 creates.
+    # The command line argument --nodevsync takes precedence over this setting.
+    # If set to 1 when udev is not running, and there are LVM2 processes
+    # waiting for udev, run 'dmsetup udevcomplete' manually to wake them up.
+    udev_sync = 1
+
     # How to fill in missing stripes if activating an incomplete volume.
     # Using "error" will make inaccessible parts of the device return
     # I/O errors on access.  You can instead use a device path, in which 

lib/activate/dev_manager.c

@@ -455,6 +455,8 @@ struct dev_manager *dev_manager_create(struct cmd_context *cmd,
 
 	dm->target_state = NULL;
 
+	dm_udev_set_sync_support(cmd->current_settings.udev_sync);
+
 	return dm;
 
       bad:

lib/commands/toolcontext.c

@@ -265,6 +265,10 @@ static int _process_config(struct cmd_context *cmd)
 		return 0;
 	}
 
+	cmd->default_settings.udev_sync = find_config_tree_int(cmd,
+								"activation/udev_sync",
+								DEFAULT_UDEV_SYNC);
+
 	cmd->stripe_filler = find_config_tree_str(cmd,
 						  "activation/missing_stripe_filler",
 						  DEFAULT_STRIPE_FILLER);

lib/commands/toolcontext.h

@@ -34,6 +34,7 @@ struct config_info {
 	int archive;		/* should we archive ? */
 	int backup;		/* should we backup ? */
 	int read_ahead;		/* DM_READ_AHEAD_NONE or _AUTO */
+	int udev_sync;
 	int cache_vgmetadata;
 	const char *msg_prefix;
 	struct format_type *fmt;

lib/config/defaults.h

@@ -68,6 +68,7 @@
 #define DEFAULT_PVMETADATACOPIES 1
 #define DEFAULT_LABELSECTOR UINT64_C(1)
 #define DEFAULT_READ_AHEAD "auto"
+#define DEFAULT_UDEV_SYNC 0
 #define DEFAULT_EXTENT_SIZE 4096	/* In KB */
 #define DEFAULT_MAX_PV 0
 #define DEFAULT_MAX_LV 0

tools/lvmcmdline.c

@@ -830,6 +830,9 @@ static int _get_settings(struct cmd_context *cmd)
 	} else
 		init_trust_cache(0);
 
+	if (arg_count(cmd, noudevsync_ARG))
+		cmd->current_settings.udev_sync = 0;
+
 	/* Handle synonyms */
 	if (!_merge_synonym(cmd, resizable_ARG, resizeable_ARG) ||
 	    !_merge_synonym(cmd, allocation_ARG, allocatable_ARG) ||