From: Adam Kwolek <adam.kwolek@intel.com>
Date: Thu, 6 Jan 2011 07:29:11 +0000 (+1100)
Subject: imsm: FIX: Division by 0
X-Git-Tag: mdadm-3.2~130
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6345120e387df797bb734bea907112ef1b226030;p=thirdparty%2Fmdadm.git

imsm: FIX: Division by 0

For general migration function blocks_per_migr_unit() has to return valid value.
If there is no valid return, 0 is returned instead and causes division by 0 error.
Additionally guard in function was added for such case.

Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/super-intel.c b/super-intel.c
index 27385bb7..ffb03437 100644
--- a/super-intel.c
+++ b/super-intel.c
@@ -1498,6 +1498,7 @@ static __u64 blocks_per_migr_unit(struct imsm_dev *dev)
 		return 0;
 
 	switch (migr_type(dev)) {
+	case MIGR_GEN_MIGR:
 	case MIGR_VERIFY:
 	case MIGR_REPAIR:
 	case MIGR_INIT: {
@@ -1534,8 +1535,6 @@ static __u64 blocks_per_migr_unit(struct imsm_dev *dev)
 		migr_chunk = migr_strip_blocks_rebuild(dev);
 		return migr_chunk * stripes_per_unit;
 	}
-	case MIGR_GEN_MIGR:
-		/* FIXME I need a number here */
 	case MIGR_STATE_CHANGE:
 	default:
 		return 0;
@@ -4877,10 +4876,14 @@ static int imsm_set_array_state(struct active_array *a, int consistent)
 			/* still reshaping, maybe update curr_migr_unit */
 			long long blocks_per_unit = blocks_per_migr_unit(dev);
 			long long unit = a->last_checkpoint;
-			unit /= blocks_per_unit;
-			if (unit > __le32_to_cpu(dev->vol.curr_migr_unit)) {
-				dev->vol.curr_migr_unit = __cpu_to_le32(unit);
-				super->updates_pending++;
+			if (blocks_per_unit) {
+				unit /= blocks_per_unit;
+				if (unit >
+				    __le32_to_cpu(dev->vol.curr_migr_unit)) {
+					dev->vol.curr_migr_unit =
+						__cpu_to_le32(unit);
+					super->updates_pending++;
+				}
 			}
 			return 0;
 		} else {