From 78fc479a691cb77600834936b4e47671dde82445 Mon Sep 17 00:00:00 2001
From: Joe Thornber <thornber@redhat.com>
Date: Tue, 13 Nov 2001 18:52:52 +0000
Subject: [PATCH] o  Deal with sparse lv arrays (on disk)

o  new fn. dev_zero which zero's an area of a device
---
 lib/device/dev-io.c         | 41 +++++++++++++++++++++++++++++++++++++
 lib/device/device.h         |  1 +
 lib/format1/disk-rep.c      | 26 ++++++++++++-----------
 lib/format1/import-export.c |  5 +++--
 lib/metadata/pv_map.c       |  1 -
 5 files changed, 59 insertions(+), 15 deletions(-)

diff --git a/lib/device/dev-io.c b/lib/device/dev-io.c
index 6ff16e8d4..1ece40263 100644
--- a/lib/device/dev-io.c
+++ b/lib/device/dev-io.c
@@ -15,6 +15,11 @@
 #include <sys/ioctl.h>
 #include <sys/mount.h>
 
+/*
+ * FIXME: all this opening and closing devices is
+ * killing performance.
+ */
+
 int dev_get_size(struct device *dev, uint64_t *size)
 {
 	int fd;
@@ -126,3 +131,39 @@ int64_t dev_write(struct device *dev, uint64_t offset,
 	close(fd);
 	return r;
 }
+
+int dev_zero(struct device *dev, uint64_t offset, int64_t len)
+{
+	int64_t r, s;
+	char buffer[4096];
+	const char *name = dev_name(dev);
+	int fd = open(name, O_WRONLY);
+
+	if (fd < 0) {
+		log_sys_error("open", name);
+		return 0;
+	}
+
+	if (lseek(fd, offset, SEEK_SET) < 0) {
+		log_sys_error("lseek", name);
+		return 0;
+	}
+
+	memset(buffer, 0, sizeof(buffer));
+	while (1) {
+		s = len > sizeof(buffer) ? sizeof(buffer) : len;
+		r = _write(fd, buffer, s);
+
+		if (r <= 0)
+			break;
+
+		len -= r;
+		if (!len) {
+			r = 1;
+			break;
+		}
+	}
+
+	close(fd);
+	return r;
+}
diff --git a/lib/device/device.h b/lib/device/device.h
index e690b979c..cdea30318 100644
--- a/lib/device/device.h
+++ b/lib/device/device.h
@@ -29,6 +29,7 @@ int64_t dev_read(struct device *dev,
 		 uint64_t offset, int64_t len, void *buffer);
 int64_t dev_write(struct device *dev,
 		  uint64_t offset, int64_t len, void *buffer);
+int dev_zero(struct device *dev, uint64_t offset, int64_t len);
 
 static inline const char *dev_name(struct device *dev) {
 	return list_item(dev->aliases.n, struct str_list)->str;
diff --git a/lib/format1/disk-rep.c b/lib/format1/disk-rep.c
index 7a590af80..f06ece0be 100644
--- a/lib/format1/disk-rep.c
+++ b/lib/format1/disk-rep.c
@@ -179,25 +179,19 @@ static int _read_uuids(struct disk_list *data)
 	return 1;
 }
 
-static int _check_lvd(struct lv_disk *lvd)
+static inline int _check_lvd(struct lv_disk *lvd)
 {
-	/* FIXME: add more checks */
-	if (lvd->lv_name[0] == '\0') {
-		log_debug("lv has no name");
-		return 0;
-	}
-
-	return 1;
+	return !(lvd->lv_name[0] == '\0');
 }
 
 static int _read_lvs(struct disk_list *data)
 {
-	int i;
+	int i, read = 0;
 	unsigned long pos;
 	struct lvd_list *ll;
+	struct vg_disk *vgd = &data->vgd;
 
-	/* FIXME May be gaps - use lv_max */
-	for(i = 0; i < data->vgd.lv_cur; i++) {
+	for(i = 0; (i < vgd->lv_max) && (read < vgd->lv_cur); i++) {
 		pos = data->pvd.lv_on_disk.base + (i * sizeof(struct lv_disk));
 		ll = pool_alloc(data->mem, sizeof(*ll));
 
@@ -208,8 +202,9 @@ static int _read_lvs(struct disk_list *data)
 			fail;
 
 		if (!_check_lvd(&ll->lvd))
-			fail;
+			continue;
 
+		read++;
 		list_add(&data->lvds, &ll->list);
 	}
 
@@ -391,6 +386,13 @@ static int _write_lvs(struct disk_list *data)
 	unsigned long pos;
 
 	pos = data->pvd.lv_on_disk.base;
+
+	if (!dev_zero(data->dev, pos, data->pvd.lv_on_disk.size)) {
+		log_err("couldn't zero lv area on device '%s'",
+			dev_name(data->dev));
+		return 0;
+	}
+
 	list_iterate(lvh, &data->lvds) {
 		struct lvd_list *ll = list_item(lvh, struct lvd_list);
 
diff --git a/lib/format1/import-export.c b/lib/format1/import-export.c
index 84dca77da..cd6922589 100644
--- a/lib/format1/import-export.c
+++ b/lib/format1/import-export.c
@@ -476,7 +476,7 @@ int export_lvs(struct disk_list *dl, struct volume_group *vg,
 	struct list *lvh;
 	struct lv_list *ll;
 	struct lvd_list *lvdl;
-	int lv_num = 1, len;
+	int lv_num = 0, len;
 
 	/*
 	 * setup the pv's extents array
@@ -498,13 +498,14 @@ int export_lvs(struct disk_list *dl, struct volume_group *vg,
 
 		export_lv(&lvdl->lvd, vg, &ll->lv, prefix);
 		lvdl->lvd.lv_number = lv_num;
-		if (!export_extents(dl, lv_num++, &ll->lv, pv)) {
+		if (!export_extents(dl, lv_num + 1, &ll->lv, pv)) {
 			stack;
 			return 0;
 		}
 
 		list_add(&dl->lvds, &lvdl->list);
 		dl->pvd.lv_cur++;
+		lv_num++;
 	}
 	return 1;
 }
diff --git a/lib/metadata/pv_map.c b/lib/metadata/pv_map.c
index 5a3a8de00..9666e1b87 100644
--- a/lib/metadata/pv_map.c
+++ b/lib/metadata/pv_map.c
@@ -29,7 +29,6 @@ static int _create_maps(struct pool *mem, struct list *pvs, struct list *maps)
 		}
 
 		list_init(&pvm->areas);
-
 		list_add(maps, &pvm->list);
 	}
 
-- 
2.43.5