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LVM2 ./WHATS_NEW lib/metadata/lv_manip.c lib/m ...
- From: jbrassow at sourceware dot org
- To: lvm-devel at redhat dot com, lvm2-cvs at sourceware dot org
- Date: 23 Feb 2012 17:36:38 -0000
- Subject: LVM2 ./WHATS_NEW lib/metadata/lv_manip.c lib/m ...
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: jbrassow@sourceware.org 2012-02-23 17:36:37
Modified files:
. : WHATS_NEW
lib/metadata : lv_manip.c raid_manip.c
tools : lvcreate.c
Log message:
Require number of stripes to be greater than parity devices in higher RAID.
Also, add some comments to code that I recently added that may be unclear
otherwise.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW.diff?cvsroot=lvm2&r1=1.2303&r2=1.2304
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/lv_manip.c.diff?cvsroot=lvm2&r1=1.364&r2=1.365
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/raid_manip.c.diff?cvsroot=lvm2&r1=1.23&r2=1.24
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/tools/lvcreate.c.diff?cvsroot=lvm2&r1=1.254&r2=1.255
--- LVM2/WHATS_NEW 2012/02/23 11:24:07 1.2303
+++ LVM2/WHATS_NEW 2012/02/23 17:36:35 1.2304
@@ -1,5 +1,6 @@
Version 2.02.93 -
====================================
+ Require number of stripes to be greater than parity devices in higher RAID.
Add LVMetaD systemd units.
Fix allocation code to allow replacement of single RAID 4/5/6 device.
Check all tags and LV names are in a valid form in vg_validate.
--- LVM2/lib/metadata/lv_manip.c 2012/02/23 03:57:23 1.364
+++ LVM2/lib/metadata/lv_manip.c 2012/02/23 17:36:36 1.365
@@ -752,6 +752,22 @@
area_count = stripes;
size = sizeof(*ah);
+
+ /*
+ * It is a requirement that RAID 4/5/6 are created with a number of
+ * stripes that is greater than the number of parity devices. (e.g
+ * RAID4/5 must have at least 2 stripes and RAID6 must have at least
+ * 3.) It is also a constraint that, when replacing individual devices
+ * in a RAID 4/5/6 array, no more devices can be replaced than
+ * there are parity devices. (Otherwise, there would not be enough
+ * redundancy to maintain the array.) Understanding these two
+ * constraints allows us to infer whether the caller of this function
+ * is intending to allocate an entire array or just replacement
+ * component devices. In the former case, we must account for the
+ * necessary parity_count. In the later case, we do not need to
+ * account for the extra parity devices because the array already
+ * exists and they only want replacement drives.
+ */
parity_count = (area_count <= segtype->parity_devs) ? 0 :
segtype->parity_devs;
alloc_count = area_count + parity_count;
--- LVM2/lib/metadata/raid_manip.c 2012/02/23 03:57:23 1.23
+++ LVM2/lib/metadata/raid_manip.c 2012/02/23 17:36:36 1.24
@@ -519,9 +519,18 @@
else if (!(segtype = get_segtype_from_string(lv->vg->cmd, "raid1")))
return_0;
+ /*
+ * The number of extents is based on the RAID type. For RAID1,
+ * each of the rimages is the same size - 'le_count'. However
+ * for RAID 4/5/6, the stripes add together (NOT including the parity
+ * devices) to equal 'le_count'. Thus, when we are allocating
+ * individual devies, we must specify how large the individual device
+ * is along with the number we want ('count').
+ */
extents = (segtype->parity_devs) ?
(lv->le_count / (seg->area_count - segtype->parity_devs)) :
lv->le_count;
+
if (!(ah = allocate_extents(lv->vg, NULL, segtype, 0, count, count,
region_size, extents, pvs,
lv->alloc, parallel_areas)))
--- LVM2/tools/lvcreate.c 2012/02/15 15:18:44 1.254
+++ LVM2/tools/lvcreate.c 2012/02/23 17:36:36 1.255
@@ -485,9 +485,10 @@
*
* For RAID 4/5/6, these values must be set.
*/
- if (!segtype_is_mirrored(lp->segtype) && (lp->stripes < 2)) {
- log_error("Number of stripes to %s not specified",
- lp->segtype->name);
+ if (!segtype_is_mirrored(lp->segtype) &&
+ (lp->stripes <= lp->segtype->parity_devs)) {
+ log_error("Number of stripes must be at least %d for %s",
+ lp->segtype->parity_devs + 1, lp->segtype->name);
return 0;
}