diff mbox series

[7/7] multipath: add option to skip multipathd delegation

Message ID 1592439867-18427-8-git-send-email-bmarzins@redhat.com (mailing list archive)
State Not Applicable, archived
Delegated to: christophe varoqui
Headers show
Series Fix muitpath/multipathd flush issue | expand

Commit Message

Benjamin Marzinski June 18, 2020, 12:24 a.m. UTC 
Add the -D option to allow users to skip delegating commands to
multipathd.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmultipath/config.h |  1 +
 multipath/main.c      | 15 +++++++++++----
 multipath/multipath.8 | 16 +++++++++++-----
 3 files changed, 23 insertions(+), 9 deletions(-)

Comments

Martin Wilck June 18, 2020, 8:44 p.m. UTC | #1 
On Wed, 2020-06-17 at 19:24 -0500, Benjamin Marzinski wrote:
> Add the -D option to allow users to skip delegating commands to
> multipathd.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> ---
>  libmultipath/config.h |  1 +
>  multipath/main.c      | 15 +++++++++++----
>  multipath/multipath.8 | 16 +++++++++++-----
>  3 files changed, 23 insertions(+), 9 deletions(-)
> 

I wonder if we really need this. We fall back to NOT_DELEGATED anyway.
If users really, really want this, they can run multipath while
multipathd is stopped.

I'm not saying it's totally useless, but the presence of this option
suggests to users that they may want to use it, which I doubt.
Perhaps we want to have it, for debugging or expert usage purpose, as a
hidden/undocumented option?

Martin
Benjamin Marzinski June 18, 2020, 11:15 p.m. UTC | #2 
On Thu, Jun 18, 2020 at 08:44:10PM +0000, Martin Wilck wrote:
> On Wed, 2020-06-17 at 19:24 -0500, Benjamin Marzinski wrote:
> > Add the -D option to allow users to skip delegating commands to
> > multipathd.
> > 
> > Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> > ---
> >  libmultipath/config.h |  1 +
> >  multipath/main.c      | 15 +++++++++++----
> >  multipath/multipath.8 | 16 +++++++++++-----
> >  3 files changed, 23 insertions(+), 9 deletions(-)
> > 
> 
> I wonder if we really need this. We fall back to NOT_DELEGATED anyway.
> If users really, really want this, they can run multipath while
> multipathd is stopped.
> 
> I'm not saying it's totally useless, but the presence of this option
> suggests to users that they may want to use it, which I doubt.
> Perhaps we want to have it, for debugging or expert usage purpose, as a
> hidden/undocumented option?

I'm fine with having it as an undocumented option.

-Ben

> 
> Martin
> 
> -- 
> Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
> SUSE  Software Solutions Germany GmbH
> HRB 36809, AG Nürnberg GF: Felix
> Imendörffer
> 

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diff mbox series

Patch

diff --git a/libmultipath/config.h b/libmultipath/config.h
index 55569360..92c61a0d 100644
--- a/libmultipath/config.h
+++ b/libmultipath/config.h
@@ -190,6 +190,7 @@  struct config {
 	int ghost_delay;
 	int find_multipaths_timeout;
 	int marginal_pathgroups;
+	int skip_delegate;
 	unsigned int version[3];
 	unsigned int sequence_nr;
 
diff --git a/multipath/main.c b/multipath/main.c
index 6a24e483..0cf7608f 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -130,9 +130,9 @@  usage (char * progname)
 {
 	fprintf (stderr, VERSION_STRING);
 	fprintf (stderr, "Usage:\n");
-	fprintf (stderr, "  %s [-v level] [-B|-d|-i|-q|-r] [-b file] [-p policy] [device]\n", progname);
-	fprintf (stderr, "  %s [-v level] [-R retries] -f device\n", progname);
-	fprintf (stderr, "  %s [-v level] [-R retries] -F\n", progname);
+	fprintf (stderr, "  %s [-v level] [-B|-d|-D|-i|-q|-r] [-b file] [-p policy] [device]\n", progname);
+	fprintf (stderr, "  %s [-v level] [-D|-R retries] -f device\n", progname);
+	fprintf (stderr, "  %s [-v level] [-D|-R retries] -F\n", progname);
 	fprintf (stderr, "  %s [-v level] [-l|-ll] [device]\n", progname);
 	fprintf (stderr, "  %s [-v level] [-a|-w] device\n", progname);
 	fprintf (stderr, "  %s [-v level] -W\n", progname);
@@ -153,6 +153,7 @@  usage (char * progname)
 		"  -C      check if a multipath device has usable paths\n"
 		"  -q      allow queue_if_no_path when multipathd is not running\n"
 		"  -d      dry run, do not create or update devmaps\n"
+		"  -D      Do not delegate command to multipathd\n"
 		"  -t      display the currently used multipathd configuration\n"
 		"  -T      display the multipathd configuration without builtin defaults\n"
 		"  -r      force devmap reload\n"
@@ -817,6 +818,9 @@  int delegate_to_multipathd(enum mpath_cmds cmd,
 	*p = '\0';
 	n = sizeof(command);
 
+	if (conf->skip_delegate)
+		return NOT_DELEGATED;
+
 	if (cmd == CMD_CREATE && conf->force_reload == FORCE_RELOAD_YES) {
 		p += snprintf(p, n, "reconfigure");
 	}
@@ -890,7 +894,7 @@  main (int argc, char *argv[])
 	multipath_conf = conf;
 	conf->retrigger_tries = 0;
 	conf->force_sync = 1;
-	while ((arg = getopt(argc, argv, ":adcChl::eFfM:v:p:b:BrR:itTquUwW")) != EOF ) {
+	while ((arg = getopt(argc, argv, ":adDcChl::eFfM:v:p:b:BrR:itTquUwW")) != EOF ) {
 		switch(arg) {
 		case 1: printf("optarg : %s\n",optarg);
 			break;
@@ -922,6 +926,9 @@  main (int argc, char *argv[])
 			if (cmd == CMD_CREATE)
 				cmd = CMD_DRY_RUN;
 			break;
+		case 'D':
+			conf->skip_delegate = 1;
+			break;
 		case 'f':
 			cmd = CMD_FLUSH_ONE;
 			break;
diff --git a/multipath/multipath.8 b/multipath/multipath.8
index 6fb8645a..16a27363 100644
--- a/multipath/multipath.8
+++ b/multipath/multipath.8
@@ -22,7 +22,7 @@  multipath \- Device mapper target autoconfig.
 .B multipath
 .RB [\| \-v\ \c
 .IR level \|]
-.RB [\| \-B | \-d | \-i | \-q | \-r \|]
+.RB [\| \-B | \-d | \-D | \-i | \-q | \-r \|]
 .RB [\| \-b\ \c
 .IR file \|]
 .RB [\| \-p\ \c
@@ -33,7 +33,7 @@  multipath \- Device mapper target autoconfig.
 .B multipath
 .RB [\| \-v\ \c
 .IR level \|]
-.RB [\| \-R\ \c
+.RB [\| \-D | \-R\ \c
 .IR retries \|]
 .B \-f device
 .
@@ -41,7 +41,7 @@  multipath \- Device mapper target autoconfig.
 .B multipath
 .RB [\| \-v\ \c
 .IR level \|]
-.RB [\| \-R\ \c
+.RB [\| \-D | \-R\ \c
 .IR retries \|]
 .B \-F
 .
@@ -125,11 +125,11 @@  the system.
 Other operation modes are chosen by using one of the following command line switches:
 .TP
 .B \-f
-Flush (remove) a multipath device map specified as parameter, if unused.
+Flush (remove) a multipath device map specified as parameter, if unused. This operation is delegated to the multipathd daemon if it's running.
 .
 .TP
 .B \-F
-Flush (remove) all unused multipath device maps.
+Flush (remove) all unused multipath device maps. This operation is delegated to the multipathd daemon if it's running.
 .
 .TP
 .B \-l
@@ -223,6 +223,12 @@  The verbosity level also controls the level of log and debug messages printed to
 Dry run, do not create or update devmaps.
 .
 .TP
+.B \-D
+Do not delegate operation to multipathd. By default, multipath delegates
+forced reloads and flushes (removes) to multipathd. Setting this option will
+cause the multipath command to execute these operations itself.
+.
+.TP
 .B \-e
 Enable all foreign libraries. This overrides the
 .I enable_foreign