[lvm-devel] LVM2 ./WHATS_NEW doc/example.conf lib/device/d ...
snitzer at sourceware.org
snitzer at sourceware.org
Mon Jul 6 19:04:26 UTC 2009
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: snitzer at sourceware.org 2009-07-06 19:04:25
Modified files:
. : WHATS_NEW
doc : example.conf
lib/device : dev-md.c device.h
lib/metadata : metadata.c
man : lvm.conf.5.in
Log message:
Use the MD device's stripe-width, instead of chunk_size, to align the
data blocks of a Physical Volume that is placed directly upon an MD
device.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW.diff?cvsroot=lvm2&r1=1.1163&r2=1.1164
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/doc/example.conf.diff?cvsroot=lvm2&r1=1.40&r2=1.41
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/device/dev-md.c.diff?cvsroot=lvm2&r1=1.13&r2=1.14
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/device/device.h.diff?cvsroot=lvm2&r1=1.39&r2=1.40
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/metadata.c.diff?cvsroot=lvm2&r1=1.230&r2=1.231
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/man/lvm.conf.5.in.diff?cvsroot=lvm2&r1=1.2&r2=1.3
--- LVM2/WHATS_NEW 2009/07/03 11:04:06 1.1163
+++ LVM2/WHATS_NEW 2009/07/06 19:04:24 1.1164
@@ -1,5 +1,6 @@
Version 2.02.49 -
================================
+ Update 'md_chunk_alignment' to use stripe-width to align PV data area.
Update test/t-inconsistent-metadata.sh to match new vg_read interface.
Add lvmcache_init() to polldaemon initialization.
Convert tools to use new vg_read / vg_read_for_update.
--- LVM2/doc/example.conf 2009/06/04 12:01:15 1.40
+++ LVM2/doc/example.conf 2009/07/06 19:04:25 1.41
@@ -94,7 +94,7 @@
md_component_detection = 1
# By default, if a PV is placed directly upon an md device, LVM2
- # will align its data blocks with the the chunk_size exposed in sysfs.
+ # will align its data blocks with the md device's stripe-width.
# 1 enables; 0 disables.
md_chunk_alignment = 1
--- LVM2/lib/device/dev-md.c 2008/10/03 14:22:18 1.13
+++ LVM2/lib/device/dev-md.c 2009/07/06 19:04:25 1.14
@@ -125,39 +125,57 @@
return ret;
}
-/*
- * Retrieve chunk size from md device using sysfs.
- */
-unsigned long dev_md_chunk_size(const char *sysfs_dir, struct device *dev)
+static int _md_sysfs_attribute_snprintf(char *path, size_t size,
+ const char *sysfs_dir,
+ struct device *dev,
+ const char *attribute)
{
- char path[PATH_MAX+1], buffer[64];
- FILE *fp;
struct stat info;
- unsigned long chunk_size_bytes = 0UL;
+ int ret = -1;
if (MAJOR(dev->dev) != md_major())
- return 0;
+ return ret;
if (!sysfs_dir || !*sysfs_dir)
- return_0;
+ return ret;
- if (dm_snprintf(path, PATH_MAX, "%s/dev/block/%d:%d/md/chunk_size",
- sysfs_dir, MAJOR(dev->dev), MINOR(dev->dev)) < 0) {
- log_error("dm_snprintf md chunk_size failed");
- return 0;
+ ret = dm_snprintf(path, size, "%s/dev/block/%d:%d/md/%s",
+ sysfs_dir, MAJOR(dev->dev), MINOR(dev->dev), attribute);
+ if (ret < 0) {
+ log_error("dm_snprintf md %s failed", attribute);
+ return ret;
}
- /* old sysfs structure */
- if (stat(path, &info) &&
- dm_snprintf(path, PATH_MAX, "%s/block/md%d/md/chunk_size",
- sysfs_dir, MINOR(dev->dev)) < 0) {
- log_error("dm_snprintf old md chunk size failed");
- return 0;
+ if (stat(path, &info) < 0) {
+ /* old sysfs structure */
+ ret = dm_snprintf(path, size, "%s/block/md%d/md/%s",
+ sysfs_dir, MINOR(dev->dev), attribute);
+ if (ret < 0) {
+ log_error("dm_snprintf old md %s failed", attribute);
+ return ret;
+ }
}
+ return ret;
+}
+
+static int _md_sysfs_attribute_scanf(const char *sysfs_dir,
+ struct device *dev,
+ const char *attribute_name,
+ const char *attribute_fmt,
+ void *attribute_value)
+{
+ char path[PATH_MAX+1], buffer[64];
+ FILE *fp;
+ int ret = 0;
+
+ if (_md_sysfs_attribute_snprintf(path, PATH_MAX, sysfs_dir,
+ dev, attribute_name) < 0)
+ return ret;
+
if (!(fp = fopen(path, "r"))) {
log_sys_error("fopen", path);
- return 0;
+ return ret;
}
if (!fgets(buffer, sizeof(buffer), fp)) {
@@ -165,22 +183,130 @@
goto out;
}
- if (sscanf(buffer, "%lu", &chunk_size_bytes) != 1) {
- log_error("sysfs file %s not in expected format: %s", path,
- buffer);
+ if ((ret = sscanf(buffer, attribute_fmt, attribute_value)) != 1) {
+ log_error("%s sysfs attr %s not in expected format: %s",
+ dev_name(dev), attribute_name, buffer);
goto out;
}
- log_very_verbose("Device %s md chunk size is %lu bytes.",
- dev_name(dev), chunk_size_bytes);
-
out:
if (fclose(fp))
log_sys_error("fclose", path);
+ return ret;
+}
+
+/*
+ * Retrieve chunk size from md device using sysfs.
+ */
+static unsigned long dev_md_chunk_size(const char *sysfs_dir,
+ struct device *dev)
+{
+ const char *attribute = "chunk_size";
+ unsigned long chunk_size_bytes = 0UL;
+
+ if (_md_sysfs_attribute_scanf(sysfs_dir, dev, attribute,
+ "%lu", &chunk_size_bytes) != 1)
+ return 0;
+
+ log_very_verbose("Device %s %s is %lu bytes.",
+ dev_name(dev), attribute, chunk_size_bytes);
+
return chunk_size_bytes >> SECTOR_SHIFT;
}
+/*
+ * Retrieve level from md device using sysfs.
+ */
+static int dev_md_level(const char *sysfs_dir, struct device *dev)
+{
+ const char *attribute = "level";
+ int level = -1;
+
+ if (_md_sysfs_attribute_scanf(sysfs_dir, dev, attribute,
+ "raid%d", &level) != 1)
+ return -1;
+
+ log_very_verbose("Device %s %s is raid%d.",
+ dev_name(dev), attribute, level);
+
+ return level;
+}
+
+/*
+ * Retrieve raid_disks from md device using sysfs.
+ */
+static int dev_md_raid_disks(const char *sysfs_dir, struct device *dev)
+{
+ const char *attribute = "raid_disks";
+ int raid_disks = 0;
+
+ if (_md_sysfs_attribute_scanf(sysfs_dir, dev, attribute,
+ "%d", &raid_disks) != 1)
+ return 0;
+
+ log_very_verbose("Device %s %s is %d.",
+ dev_name(dev), attribute, raid_disks);
+
+ return raid_disks;
+}
+
+/*
+ * Calculate stripe width of md device using its sysfs files.
+ */
+unsigned long dev_md_stripe_width(const char *sysfs_dir, struct device *dev)
+{
+ unsigned long chunk_size_sectors = 0UL;
+ unsigned long stripe_width_sectors = 0UL;
+ int level, raid_disks, data_disks;
+
+ chunk_size_sectors = dev_md_chunk_size(sysfs_dir, dev);
+ if (!chunk_size_sectors)
+ return 0;
+
+ level = dev_md_level(sysfs_dir, dev);
+ if (level < 0)
+ return 0;
+
+ raid_disks = dev_md_raid_disks(sysfs_dir, dev);
+ if (!raid_disks)
+ return 0;
+
+ /* The raid level governs the number of data disks. */
+ switch (level) {
+ case 0:
+ /* striped md does not have any parity disks */
+ data_disks = raid_disks;
+ break;
+ case 1:
+ case 10:
+ /* mirrored md effectively has 1 data disk */
+ data_disks = 1;
+ break;
+ case 4:
+ case 5:
+ /* both raid 4 and 5 have a single parity disk */
+ data_disks = raid_disks - 1;
+ break;
+ case 6:
+ /* raid 6 has 2 parity disks */
+ data_disks = raid_disks - 2;
+ break;
+ default:
+ log_error("Device %s has an unknown md raid level: %d",
+ dev_name(dev), level);
+ return 0;
+ }
+
+ stripe_width_sectors = chunk_size_sectors * data_disks;
+
+ log_very_verbose("Device %s stripe-width is %lu bytes.",
+ dev_name(dev),
+ stripe_width_sectors << SECTOR_SHIFT);
+
+ return stripe_width_sectors;
+}
+
#else
int dev_is_md(struct device *dev __attribute((unused)),
@@ -189,8 +315,8 @@
return 0;
}
-unsigned long dev_md_chunk_size(const char *sysfs_dir __attribute((unused)),
- struct device *dev __attribute((unused)))
+unsigned long dev_md_stripe_width(const char *sysfs_dir __attribute((unused)),
+ struct device *dev __attribute((unused)))
{
return 0UL;
}
--- LVM2/lib/device/device.h 2009/05/20 11:09:49 1.39
+++ LVM2/lib/device/device.h 2009/07/06 19:04:25 1.40
@@ -96,7 +96,7 @@
/* Does device contain md superblock? If so, where? */
int dev_is_md(struct device *dev, uint64_t *sb);
int dev_is_swap(struct device *dev, uint64_t *signature);
-unsigned long dev_md_chunk_size(const char *sysfs_dir, struct device *dev);
+unsigned long dev_md_stripe_width(const char *sysfs_dir, struct device *dev);
int is_partitioned_dev(struct device *dev);
--- LVM2/lib/metadata/metadata.c 2009/07/01 17:03:38 1.230
+++ LVM2/lib/metadata/metadata.c 2009/07/06 19:04:25 1.231
@@ -81,13 +81,13 @@
goto out;
/*
- * Align to chunk size of underlying md device if present
+ * Align to stripe-width of underlying md device if present
*/
if (find_config_tree_bool(pv->fmt->cmd, "devices/md_chunk_alignment",
DEFAULT_MD_CHUNK_ALIGNMENT))
pv->pe_align = MAX(pv->pe_align,
- dev_md_chunk_size(pv->fmt->cmd->sysfs_dir,
- pv->dev));
+ dev_md_stripe_width(pv->fmt->cmd->sysfs_dir,
+ pv->dev));
log_very_verbose("%s: Setting PE alignment to %lu sectors.",
dev_name(pv->dev), pv->pe_align);
--- LVM2/man/lvm.conf.5.in 2009/02/22 19:00:28 1.2
+++ LVM2/man/lvm.conf.5.in 2009/07/06 19:04:25 1.3
@@ -134,8 +134,8 @@
has been reused without wiping the md superblocks first.
.IP
\fBmd_chunk_alignment\fP \(em If set to 1, and a Physical Volume is placed
-directly upon an md device, LVM2 will align its data blocks with the the
-chunk_size exposed in sysfs.
+directly upon an md device, LVM2 will align its data blocks with the
+md device's stripe-width.
.IP
\fBdata_alignment\fP \(em Default alignment (in KB) of start of data area
when creating a new Physical Volume using the \fBlvm2\fP format.
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