[lvm-devel] LVM2 ./WHATS_NEW lib/format_text/import_vsn1.c

[mbroz at sourceware.org]

CVSROOT:	/cvs/lvm2
Module name:	LVM2
Changes by:	mbroz at sourceware.org	2010-03-31 17:20:03

Modified files:
	.              : WHATS_NEW 
	lib/format_text: import_vsn1.c 

Log message:
	Use hash table for quick lv reference when reading metadata.
	
	The _read_vg uses already hash for PVs to optimise
	reading of large VGs and avoiding repeated PV list traversing.
	
	Use the same aproach to speed up parsing VG with many LVs.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW.diff?cvsroot=lvm2&r1=1.1492&r2=1.1493
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/format_text/import_vsn1.c.diff?cvsroot=lvm2&r1=1.69&r2=1.70

--- LVM2/WHATS_NEW	2010/03/31 12:06:30	1.1492
+++ LVM2/WHATS_NEW	2010/03/31 17:20:02	1.1493
@@ -1,5 +1,6 @@
 Version 2.02.63 -  
 ================================
+  Use hash table of LVs to speed up parsing of text metadata with many LVs.
   Fix two messages, add a whitespace and parentheses
   When dmeventd is not forking because of -d flag, don't kill the parent process
   Fix 'make install' when $(builddir) is different from $(srcdir).
--- LVM2/lib/format_text/import_vsn1.c	2010/03/17 02:11:19	1.69
+++ LVM2/lib/format_text/import_vsn1.c	2010/03/31 17:20:03	1.70
@@ -28,6 +28,7 @@
 			   struct volume_group * vg, struct config_node * pvn,
 			   struct config_node * vgn,
 			   struct dm_hash_table * pv_hash,
+			   struct dm_hash_table * lv_hash,
 			   unsigned *scan_done_once,
 			   unsigned report_missing_devices);
 
@@ -155,7 +156,9 @@
 static int _read_pv(struct format_instance *fid, struct dm_pool *mem,
 		    struct volume_group *vg, struct config_node *pvn,
 		    struct config_node *vgn __attribute((unused)),
-		    struct dm_hash_table *pv_hash, unsigned *scan_done_once,
+		    struct dm_hash_table *pv_hash,
+		    struct dm_hash_table *lv_hash __attribute((unused)),
+		    unsigned *scan_done_once,
 		    unsigned report_missing_devices)
 {
 	struct physical_volume *pv;
@@ -495,6 +498,7 @@
 			 struct volume_group *vg, struct config_node *lvn,
 			 struct config_node *vgn __attribute((unused)),
 			 struct dm_hash_table *pv_hash __attribute((unused)),
+			 struct dm_hash_table *lv_hash,
 			 unsigned *scan_done_once __attribute((unused)),
 			 unsigned report_missing_devices __attribute((unused)))
 {
@@ -555,6 +559,9 @@
 		return 0;
 	}
 
+	if (!dm_hash_insert(lv_hash, lv->name, lv))
+		return_0;
+
 	return link_lv_to_vg(vg, lv);
 }
 
@@ -563,19 +570,17 @@
 			struct volume_group *vg, struct config_node *lvn,
 			struct config_node *vgn __attribute((unused)),
 			struct dm_hash_table *pv_hash,
+			struct dm_hash_table *lv_hash,
 			unsigned *scan_done_once __attribute((unused)),
 			unsigned report_missing_devices __attribute((unused)))
 {
 	struct logical_volume *lv;
-	struct lv_list *lvl;
 
-	if (!(lvl = find_lv_in_vg(vg, lvn->key))) {
+	if (!(lv = dm_hash_lookup(lv_hash, lvn->key))) {
 		log_error("Lost logical volume reference %s", lvn->key);
 		return 0;
 	}
 
-	lv = lvl->lv;
-
 	if (!(lvn = lvn->child)) {
 		log_error("Empty logical volume section.");
 		return 0;
@@ -617,7 +622,9 @@
 			  const char *section, section_fn fn,
 			  struct dm_pool *mem,
 			  struct volume_group *vg, struct config_node *vgn,
-			  struct dm_hash_table *pv_hash, int optional,
+			  struct dm_hash_table *pv_hash,
+			  struct dm_hash_table *lv_hash,
+			  int optional,
 			  unsigned *scan_done_once)
 {
 	struct config_node *n;
@@ -634,7 +641,7 @@
 	}
 
 	for (n = n->child; n; n = n->sib) {
-		if (!fn(fid, mem, vg, n, vgn, pv_hash, scan_done_once, report_missing_devices))
+		if (!fn(fid, mem, vg, n, vgn, pv_hash, lv_hash, scan_done_once, report_missing_devices))
 			return_0;
 	}
 
@@ -647,7 +654,7 @@
 {
 	struct config_node *vgn, *cn;
 	struct volume_group *vg;
-	struct dm_hash_table *pv_hash = NULL;
+	struct dm_hash_table *pv_hash = NULL, *lv_hash = NULL;
 	struct dm_pool *mem = dm_pool_create("lvm2 vg_read", VG_MEMPOOL_CHUNK);
 	unsigned scan_done_once = use_cached_pvs;
 
@@ -742,7 +749,7 @@
 	}
 
 	/*
-	 * The pv hash memoises the pv section names -> pv
+	 * The pv hash memorises the pv section names -> pv
 	 * structures.
 	 */
 	if (!(pv_hash = dm_hash_create(32))) {
@@ -752,7 +759,7 @@
 
 	dm_list_init(&vg->pvs);
 	if (!_read_sections(fid, "physical_volumes", _read_pv, mem, vg,
-			    vgn, pv_hash, 0, &scan_done_once)) {
+			    vgn, pv_hash, lv_hash, 0, &scan_done_once)) {
 		log_error("Couldn't find all physical volumes for volume "
 			  "group %s.", vg->name);
 		goto bad;
@@ -769,15 +776,24 @@
 		goto bad;
 	}
 
+	/*
+	 * The lv hash memorises the lv section names -> lv
+	 * structures.
+	 */
+	if (!(lv_hash = dm_hash_create(32))) {
+		log_error("Couldn't create hash table.");
+		goto bad;
+	}
+
 	if (!_read_sections(fid, "logical_volumes", _read_lvnames, mem, vg,
-			    vgn, pv_hash, 1, NULL)) {
+			    vgn, pv_hash, lv_hash, 1, NULL)) {
 		log_error("Couldn't read all logical volume names for volume "
 			  "group %s.", vg->name);
 		goto bad;
 	}
 
 	if (!_read_sections(fid, "logical_volumes", _read_lvsegs, mem, vg,
-			    vgn, pv_hash, 1, NULL)) {
+			    vgn, pv_hash, lv_hash, 1, NULL)) {
 		log_error("Couldn't read all logical volumes for "
 			  "volume group %s.", vg->name);
 		goto bad;
@@ -790,6 +806,7 @@
 	}
 
 	dm_hash_destroy(pv_hash);
+	dm_hash_destroy(lv_hash);
 
 	/*
 	 * Finished.
@@ -800,6 +817,9 @@
 	if (pv_hash)
 		dm_hash_destroy(pv_hash);
 
+	if (lv_hash)
+		dm_hash_destroy(lv_hash);
+
 	dm_pool_destroy(mem);
 	return NULL;
 }