[lvm-devel] LVM2 lib/metadata/metadata.c tools/toollib.c

[wysochanski at sourceware.org]

CVSROOT:	/cvs/lvm2
Module name:	LVM2
Changes by:	wysochanski at sourceware.org	2010-03-18 17:29:13

Modified files:
	lib/metadata   : metadata.c 
	tools          : toollib.c 

Log message:
	Avoid scanning all pvs in the system if operating on a device with mdas.
	
	When we pv_read() a device that has an orphan vgname, we might need to scan
	the system to be sure this is true.  However, if the PV has mdas, there's
	no way possible for it to have an orphan vgname unless it is a true orphan.
	Some areas of the code were optimized to take advantage of this fact, while
	others were not (we would still do the expensive scan if a device had mdas
	but had an orphan VG).
	
	This patch unifies the code so that every place we are operating on such
	a PV, we skip the expensive scan if there are mdas.
	
	Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
	Acked-by: Petr Rockai <prockai at redhat.com>
	Acked-by: Alasdair G Kergon <agk at redhat.com>

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/metadata.c.diff?cvsroot=lvm2&r1=1.323&r2=1.324
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/tools/toollib.c.diff?cvsroot=lvm2&r1=1.187&r2=1.188

--- LVM2/lib/metadata/metadata.c	2010/03/17 14:44:18	1.323
+++ LVM2/lib/metadata/metadata.c	2010/03/18 17:29:12	1.324
@@ -1251,11 +1251,14 @@
 	struct device *dev;
 	uint64_t md_superblock, swap_signature;
 	int wipe_md, wipe_swap;
+	struct dm_list mdas;
+
+	dm_list_init(&mdas);
 
 	/* FIXME Check partition type is LVM unless --force is given */
 
 	/* Is there a pv here already? */
-	pv = pv_read(cmd, name, NULL, NULL, 0, 0);
+	pv = pv_read(cmd, name, &mdas, NULL, 0, 0);
 
 	/*
 	 * If a PV has no MDAs it may appear to be an orphan until the
@@ -1263,7 +1266,7 @@
 	 * this means checking every VG by scanning every PV on the
 	 * system.
 	 */
-	if (pv && is_orphan(pv)) {
+	if (pv && is_orphan(pv) && !dm_list_size(&mdas)) {
 		if (!scan_vgs_for_pvs(cmd))
 			return_0;
 		pv = pv_read(cmd, name, NULL, NULL, 0, 0);
@@ -1747,14 +1750,16 @@
 static struct physical_volume *_find_pv_by_name(struct cmd_context *cmd,
 			 			const char *pv_name)
 {
+	struct dm_list mdas;
 	struct physical_volume *pv;
 
-	if (!(pv = _pv_read(cmd, cmd->mem, pv_name, NULL, NULL, 1, 0))) {
+	dm_list_init(&mdas);
+	if (!(pv = _pv_read(cmd, cmd->mem, pv_name, &mdas, NULL, 1, 0))) {
 		log_error("Physical volume %s not found", pv_name);
 		return NULL;
 	}
 
-	if (is_orphan_vg(pv->vg_name)) {
+	if (is_orphan_vg(pv->vg_name) && !dm_list_size(&mdas)) {
 		/* If a PV has no MDAs - need to search all VGs for it */
 		if (!scan_vgs_for_pvs(cmd))
 			return_NULL;
--- LVM2/tools/toollib.c	2010/03/16 16:57:05	1.187
+++ LVM2/tools/toollib.c	2010/03/18 17:29:12	1.188
@@ -642,6 +642,7 @@
 	struct str_list *sll;
 	char *tagname;
 	int scanned = 0;
+	struct dm_list mdas;
 
 	dm_list_init(&tags);
 
@@ -682,7 +683,9 @@
 				}
 				pv = pvl->pv;
 			} else {
-				if (!(pv = pv_read(cmd, argv[opt], NULL,
+
+				dm_list_init(&mdas);
+				if (!(pv = pv_read(cmd, argv[opt], &mdas,
 						   NULL, 1, scan_label_only))) {
 					log_error("Failed to read physical "
 						  "volume \"%s\"", argv[opt]);
@@ -697,7 +700,8 @@
 				 * means checking every VG by scanning every
 				 * PV on the system.
 				 */
-				if (!scanned && is_orphan(pv)) {
+				if (!scanned && is_orphan(pv) &&
+				    !dm_list_size(&mdas)) {
 					if (!scan_label_only &&
 					    !scan_vgs_for_pvs(cmd)) {
 						stack;