update_plex_config: Eliminate a potential divide-by-zero.

Tripped-over-by: Karl Pielorz <kpielorz@tdx.co.uk>

1 files changed, 15 insertions, 13 deletions

diff --git a/sys/dev/vinum/vinumconfig.c b/sys/dev/vinum/vinumconfig.c
index 7fc6520..67cd1c6 100644
--- a/sys/dev/vinum/vinumconfig.c
+++ b/sys/dev/vinum/vinumconfig.c
@@ -1826,19 +1826,21 @@ update_plex_config(int plexno, int diskconfig)
 	 * the stripe size.  If not, trim off the end
 	 * of each subdisk and return it to the drive.
 	 */
-	remainder = (int) (plex->length % ((u_int64_t) plex->stripesize * data_sds)); /* are we exact? */
-	if (remainder) {				    /* no */
-	    log(LOG_INFO, "vinum: removing %d blocks of partial stripe at the end of %s\n",
-		remainder,
-		plex->name);
-	    plex->length -= remainder;			    /* shorten the plex */
-	    remainder /= data_sds;			    /* spread the remainder amongst the sds */
-	    for (sdno = 0; sdno < plex->subdisks; sdno++) {
-		sd = &SD[plex->sdnos[sdno]];		    /* point to the subdisk */
-		return_drive_space(sd->driveno,		    /* return the space */
-		    sd->driveoffset + sd->sectors - remainder,
-		    remainder);
-		sd->sectors -= remainder;		    /* and shorten it */
+	if (plex->length > 0) {
+	    remainder = (int) (plex->length % ((u_int64_t) plex->stripesize * data_sds)); /* are we exact? */
+	    if (remainder) {				    /* no */
+		log(LOG_INFO, "vinum: removing %d blocks of partial stripe at the end of %s\n",
+		    remainder,
+		    plex->name);
+		plex->length -= remainder;		    /* shorten the plex */
+		remainder /= data_sds;			    /* spread the remainder amongst the sds */
+		for (sdno = 0; sdno < plex->subdisks; sdno++) {
+		    sd = &SD[plex->sdnos[sdno]];	    /* point to the subdisk */
+		    return_drive_space(sd->driveno,	    /* return the space */
+			sd->driveoffset + sd->sectors - remainder,
+			remainder);
+		    sd->sectors -= remainder;		    /* and shorten it */
+		}
 	    }
 	}
     }