device-mapper-multipath/0099-multipathd-Add-auto_resize-config-option.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Thu, 9 Nov 2023 18:46:16 -0500
Subject: [PATCH] multipathd: Add auto_resize config option

This option gives multipathd the ability to automatically resize a
device when it detects that all of the path devices have changed. By
default it is set to never, and multipathd will continue to work like it
always has, where a users must manually resize a multipath device.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
---
 libmultipath/config.h      |  1 +
 libmultipath/defaults.h    |  1 +
 libmultipath/dict.c        | 38 ++++++++++++++++++++++++++++++++++++++
 libmultipath/dict.h        |  1 +
 libmultipath/structs.h     |  7 +++++++
 multipath/multipath.conf.5 | 15 +++++++++++++++
 multipathd/main.c          | 28 ++++++++++++++++++++++++++++
 7 files changed, 91 insertions(+)

diff --git a/libmultipath/config.h b/libmultipath/config.h
index b0ee8241..5807ac68 100644
--- a/libmultipath/config.h
+++ b/libmultipath/config.h
@@ -201,6 +201,7 @@ struct config {
 	int skip_delegate;
 	unsigned int sequence_nr;
 	int recheck_wwid;
+	int auto_resize;
 
 	char * multipath_dir;
 	char * selector;
diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
index cec82f07..c3788bbc 100644
--- a/libmultipath/defaults.h
+++ b/libmultipath/defaults.h
@@ -54,6 +54,7 @@
 #define DEFAULT_UNKNOWN_FIND_MULTIPATHS_TIMEOUT 1
 #define DEFAULT_ALL_TG_PT ALL_TG_PT_OFF
 #define DEFAULT_RECHECK_WWID RECHECK_WWID_OFF
+#define DEFAULT_AUTO_RESIZE AUTO_RESIZE_NEVER
 /* Enable no foreign libraries by default */
 #define DEFAULT_ENABLE_FOREIGN "NONE"
 
diff --git a/libmultipath/dict.c b/libmultipath/dict.c
index 0c66c1e1..c4db60df 100644
--- a/libmultipath/dict.c
+++ b/libmultipath/dict.c
@@ -1736,6 +1736,43 @@ declare_hw_snprint(recheck_wwid, print_yes_no_undef)
 
 declare_def_range_handler(uxsock_timeout, DEFAULT_REPLY_TIMEOUT, INT_MAX)
 
+static int
+def_auto_resize_handler(struct config *conf, vector strvec, const char *file,
+			int line_nr)
+{
+	char * buff;
+
+	buff = set_value(strvec);
+	if (!buff)
+		return 1;
+
+	if (strcmp(buff, "never") == 0)
+		conf->auto_resize = AUTO_RESIZE_NEVER;
+	else if (strcmp(buff, "grow_only") == 0)
+		conf->auto_resize = AUTO_RESIZE_GROW_ONLY;
+	else if (strcmp(buff, "grow_shrink") == 0)
+		conf->auto_resize = AUTO_RESIZE_GROW_SHRINK;
+	else
+		condlog(1, "%s line %d, invalid value for auto_resize: \"%s\"",
+			file, line_nr, buff);
+
+	free(buff);
+	return 0;
+}
+
+int
+print_auto_resize(struct strbuf *buff, long v)
+{
+	if (!v)
+		return 0;
+	return append_strbuf_quoted(buff,
+			v == AUTO_RESIZE_GROW_ONLY ? "grow_only" :
+			v == AUTO_RESIZE_GROW_SHRINK ? "grow_shrink" :
+			"never");
+}
+
+declare_def_snprint(auto_resize, print_auto_resize)
+
 static int
 hw_vpd_vendor_handler(struct config *conf, vector strvec, const char *file,
 		      int line_nr)
@@ -2202,6 +2239,7 @@ init_keywords(vector keywords)
 	install_keyword("remove_retries", &def_remove_retries_handler, &snprint_def_remove_retries);
 	install_keyword("max_sectors_kb", &def_max_sectors_kb_handler, &snprint_def_max_sectors_kb);
 	install_keyword("ghost_delay", &def_ghost_delay_handler, &snprint_def_ghost_delay);
+	install_keyword("auto_resize", &def_auto_resize_handler, &snprint_def_auto_resize);
 	install_keyword("find_multipaths_timeout",
 			&def_find_multipaths_timeout_handler,
 			&snprint_def_find_multipaths_timeout);
diff --git a/libmultipath/dict.h b/libmultipath/dict.h
index d80f990a..d963b4ad 100644
--- a/libmultipath/dict.h
+++ b/libmultipath/dict.h
@@ -19,4 +19,5 @@ int print_dev_loss(struct strbuf *buff, unsigned long v);
 int print_reservation_key(struct strbuf *buff,
 			  struct be64 key, uint8_t flags, int source);
 int print_off_int_undef(struct strbuf *buff, long v);
+int print_auto_resize(struct strbuf *buff, long v);
 #endif /* _DICT_H */
diff --git a/libmultipath/structs.h b/libmultipath/structs.h
index b4252ab5..8c2d7131 100644
--- a/libmultipath/structs.h
+++ b/libmultipath/structs.h
@@ -167,6 +167,13 @@ enum queue_mode_states {
 	QUEUE_MODE_RQ,
 };
 
+enum auto_resize_state {
+	AUTO_RESIZE_UNDEF = 0,
+	AUTO_RESIZE_NEVER,
+	AUTO_RESIZE_GROW_ONLY,
+	AUTO_RESIZE_GROW_SHRINK,
+};
+
 #define PROTOCOL_UNSET -1
 
 enum scsi_protocol {
diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
index 789f0bfc..38eb5c90 100644
--- a/multipath/multipath.conf.5
+++ b/multipath/multipath.conf.5
@@ -1293,6 +1293,21 @@ The default is: \fBno\fR
 .
 .
 .TP
+.B auto_resize
+Controls when multipathd will automatically resize a multipath device.  If set
+to \fInever\fR, multipath devices must always be manually resized by either
+running \fBmultipathd resize map <name>\fR.  If set to \fIgrow_only\fR, when
+multipathd detects that all of a multipath device's paths have increased in
+size, it will automatically grow the multipath device to the new size. If set
+to \fIgrow_shrink\fR, multipathd will also automatically shrink the device
+once it detects all of its paths have decreased in size.
+.RS
+.TP
+The default is: \fBnever\fR
+.RE
+.
+.
+.TP
 .B enable_foreign
 Enables or disables foreign libraries (see section
 .I FOREIGN MULTIPATH SUPPORT
diff --git a/multipathd/main.c b/multipathd/main.c
index d99cad72..6d1a5e4e 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -1439,6 +1439,11 @@ uev_update_path (struct uevent *uev, struct vectors * vecs)
 	if (pp) {
 		struct multipath *mpp = pp->mpp;
 		char wwid[WWID_SIZE];
+		int auto_resize;
+
+		conf = get_multipath_config();
+		auto_resize = conf->auto_resize;
+		put_multipath_config(conf);
 
 		if (pp->initialized == INIT_REQUESTED_UDEV) {
 			needs_reinit = 1;
@@ -1489,6 +1494,29 @@ uev_update_path (struct uevent *uev, struct vectors * vecs)
 				}
 			}
 		}
+		if (auto_resize != AUTO_RESIZE_NEVER &&
+		    !mpp->wait_for_udev) {
+			struct pathgroup *pgp;
+			struct path *pp2;
+			unsigned int i, j;
+			unsigned long long orig_size = mpp->size;
+
+			if (!pp->size || pp->size == mpp->size ||
+			    (pp->size < mpp->size &&
+			     auto_resize == AUTO_RESIZE_GROW_ONLY))
+				goto out;
+
+			vector_foreach_slot(mpp->pg, pgp, i)
+				vector_foreach_slot (pgp->paths, pp2, j)
+					if (pp2->size && pp2->size != pp->size)
+						goto out;
+			retval = resize_map(mpp, pp->size, vecs);
+			if (retval == 2)
+				condlog(2, "%s: map removed during resize", pp->dev);
+			else if (retval == 0)
+				condlog(2, "%s: resized map from %llu to %llu",
+					mpp->alias, orig_size, pp->size);
+		}
 	}
 out:
 	lock_cleanup_pop(vecs->lock);