[lvm-devel] [PATCH] improve dmeventd monitoring option processing

[Mike Snitzer]

Add "monitoring" option to "dmeventd" section of lvm.conf

Have clvmd consult the lvm.conf "dmeventd/monitoring" too.

Error out when both --monitor and --ignoremonitoring are provided.

Clarify that '--monitor' controls the start and stop of monitoring in
the {vg,lv}change man pages.

NOTE: should this identical code in {vg,lv}change.c be split out into
toollib.c?

Signed-off-by: Mike Snitzer <snitzer at redhat.com>
---
 daemons/clvmd/lvm-functions.c |    8 ++++++--
 doc/example.conf              |    5 +++++
 man/lvchange.8.in             |    3 +--
 man/vgchange.8.in             |    3 +--
 tools/lvchange.c              |   21 +++++++++++++++++----
 tools/vgchange.c              |   21 +++++++++++++++++----
 6 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/daemons/clvmd/lvm-functions.c b/daemons/clvmd/lvm-functions.c
index 02d401b..5d4b867 100644
--- a/daemons/clvmd/lvm-functions.c
+++ b/daemons/clvmd/lvm-functions.c
@@ -542,8 +542,12 @@ int do_lock_lv(unsigned char command, unsigned char lock_flags, char *resource)
 	if (lock_flags & LCK_MIRROR_NOSYNC_MODE)
 		init_mirror_in_sync(0);
 
-	if (!(lock_flags & LCK_DMEVENTD_MONITOR_MODE))
-		init_dmeventd_monitor(DEFAULT_DMEVENTD_MONITOR);
+	if (!(lock_flags & LCK_DMEVENTD_MONITOR_MODE)) {
+		int dmeventd_mode =
+			find_config_tree_bool(cmd, "dmeventd/monitoring",
+					      DEFAULT_DMEVENTD_MONITOR);
+		init_dmeventd_monitor(dmeventd_mode);
+	}
 
 	cmd->partial_activation = 0;
 
diff --git a/doc/example.conf b/doc/example.conf
index 511e20c..2f9d5ee 100644
--- a/doc/example.conf
+++ b/doc/example.conf
@@ -469,6 +469,11 @@ activation {
 # Event daemon
 #
 dmeventd {
+    # Monitoring is enabled by default when using vgchange or
+    # lvchange.  Set to 0 to disable monitoring or use the
+    # --ignoremonitoring option.
+    monitoring = 1
+
     # mirror_library is the library used when monitoring a mirror device.
     #
     # "libdevmapper-event-lvm2mirror.so" attempts to recover from
diff --git a/man/lvchange.8.in b/man/lvchange.8.in
index 08a83c4..99f9bf3 100644
--- a/man/lvchange.8.in
+++ b/man/lvchange.8.in
@@ -56,8 +56,7 @@ of your data.
 Set the minor number.
 .TP
 .I \-\-monitor y|n
-Controls whether or not a mirrored logical volume is monitored by
-dmeventd, if it is installed.
+Start or stop monitoring a logical volume, if dmeventd is installed.
 If a device used by a monitored mirror reports an I/O error,
 the failure is handled according to 
 \fBmirror_image_fault_policy\fP and \fBmirror_log_fault_policy\fP
diff --git a/man/vgchange.8.in b/man/vgchange.8.in
index 5013c1e..e01158a 100644
--- a/man/vgchange.8.in
+++ b/man/vgchange.8.in
@@ -78,8 +78,7 @@ are not marked as clustered.
 Generate new random UUID for specified Volume Groups.
 .TP
 .BR \-\-monitor " " { y | n }
-Controls whether or not a mirrored logical volume is monitored by
-dmeventd, if it is installed.
+Start or stop monitoring a logical volume, if dmeventd is installed.
 If a device used by a monitored mirror reports an I/O error,
 the failure is handled according to 
 .BR mirror_image_fault_policy
diff --git a/tools/lvchange.c b/tools/lvchange.c
index 2d7955e..711217f 100644
--- a/tools/lvchange.c
+++ b/tools/lvchange.c
@@ -518,7 +518,7 @@ static int lvchange_single(struct cmd_context *cmd, struct logical_volume *lv,
 			   void *handle __attribute((unused)))
 {
 	int doit = 0, docmds = 0;
-	int archived = 0;
+	int dmeventd_mode, archived = 0;
 	struct logical_volume *origin;
 
 	if (!(lv->vg->status & LVM_WRITE) &&
@@ -575,9 +575,22 @@ static int lvchange_single(struct cmd_context *cmd, struct logical_volume *lv,
 		return ECMD_FAILED;
 	}
 
-	init_dmeventd_monitor(arg_int_value(cmd, monitor_ARG,
-					    (is_static() || arg_count(cmd, ignoremonitoring_ARG)) ?
-					    DMEVENTD_MONITOR_IGNORE : DEFAULT_DMEVENTD_MONITOR));
+	if (arg_count(cmd, monitor_ARG) &&
+	    arg_count(cmd, ignoremonitoring_ARG)) {
+		log_error("Conflicting monitor and ignoremonitoring options");
+		return ECMD_FAILED;
+	}
+
+	dmeventd_mode = DEFAULT_DMEVENTD_MONITOR;
+	if (arg_count(cmd, monitor_ARG))
+		dmeventd_mode = arg_int_value(cmd, monitor_ARG,
+					      DEFAULT_DMEVENTD_MONITOR);
+	else if (is_static() || arg_count(cmd, ignoremonitoring_ARG) ||
+		 !find_config_tree_bool(cmd, "dmeventd/monitoring",
+					DEFAULT_DMEVENTD_MONITOR))
+		dmeventd_mode = DMEVENTD_MONITOR_IGNORE;
+
+	init_dmeventd_monitor(dmeventd_mode);
 
 	/*
 	 * FIXME: DEFAULT_BACKGROUND_POLLING should be "unspecified".
diff --git a/tools/vgchange.c b/tools/vgchange.c
index 6d869f9..f343584 100644
--- a/tools/vgchange.c
+++ b/tools/vgchange.c
@@ -522,16 +522,29 @@ static int vgchange_single(struct cmd_context *cmd, const char *vg_name,
 			   struct volume_group *vg,
 			   void *handle __attribute((unused)))
 {
-	int r = ECMD_FAILED;
+	int dmeventd_mode, r = ECMD_FAILED;
 
 	if (vg_is_exported(vg)) {
 		log_error("Volume group \"%s\" is exported", vg_name);
 		return ECMD_FAILED;
 	}
 
-	init_dmeventd_monitor(arg_int_value(cmd, monitor_ARG,
-					    (is_static() || arg_count(cmd, ignoremonitoring_ARG)) ?
-					    DMEVENTD_MONITOR_IGNORE : DEFAULT_DMEVENTD_MONITOR));
+	if (arg_count(cmd, monitor_ARG) &&
+	    arg_count(cmd, ignoremonitoring_ARG)) {
+		log_error("Conflicting monitor and ignoremonitoring options");
+		return ECMD_FAILED;
+	}
+
+	dmeventd_mode = DEFAULT_DMEVENTD_MONITOR;
+	if (arg_count(cmd, monitor_ARG))
+		dmeventd_mode = arg_int_value(cmd, monitor_ARG,
+					      DEFAULT_DMEVENTD_MONITOR);
+	else if (is_static() || arg_count(cmd, ignoremonitoring_ARG) ||
+		 !find_config_tree_bool(cmd, "dmeventd/monitoring",
+					DEFAULT_DMEVENTD_MONITOR))
+		dmeventd_mode = DMEVENTD_MONITOR_IGNORE;
+
+	init_dmeventd_monitor(dmeventd_mode);
 
 	/*
 	 * FIXME: DEFAULT_BACKGROUND_POLLING should be "unspecified".