Fix free-space leak truncating files in JFS.

There was a bug truncating large files to non-zero lengths which led
to space not being marked free in the block map.

fs/jfs/jfs_txnmgr.c

@@ -720,6 +720,8 @@ tlock_t *txLock(tid_t tid, struct inode *ip, metapage_t * mp, int type)
 			    le16_to_cpu(p->header.nextindex);
 		}
 		xtlck->lwm.length = 0;	/* ! */
+		xtlck->twm.offset = 0;
+		xtlck->hwm.offset = 0;
 
 		xtlck->index = 2;
 		break;
@@ -1868,6 +1870,7 @@ void xtLog(log_t * log, tblock_t * tblk, lrd_t * lrd, tlock_t * tlck)
 	 */
 	if (tlck->type & tlckTRUNCATE) {
 		pxd_t tpxd;	/* truncated extent of xad */
+		int twm;
 
 		/*
 		 * For truncation the entire linelock may be used, so it would
@@ -1881,6 +1884,7 @@ void xtLog(log_t * log, tblock_t * tblk, lrd_t * lrd, tlock_t * tlck)
 		if (lwm == 0)
 			lwm = XTPAGEMAXSLOT;
 		hwm = xtlck->hwm.offset;
+		twm = xtlck->twm.offset;
 
 		/*
 		 *      write log records
@@ -1906,9 +1910,9 @@ void xtLog(log_t * log, tblock_t * tblk, lrd_t * lrd, tlock_t * tlck)
 		}
 
 		/*
-		 * truncate entry XAD[hwm == next - 1]:
+		 * truncate entry XAD[twm == next - 1]:
 		 */
-		if (hwm == next - 1) {
+		if (twm == next - 1) {
 			/* init LOG_UPDATEMAP for logredo() to update bmap for
 			 * free of truncated delta extent of the truncated
 			 * entry XAD[next - 1]:
@@ -1975,9 +1979,9 @@ void xtLog(log_t * log, tblock_t * tblk, lrd_t * lrd, tlock_t * tlck)
 		}
 
 		/*
-		 * truncate entry XAD[hwm == next - 1]:
+		 * truncate entry XAD[twm == next - 1]:
 		 */
-		if (hwm == next - 1) {
+		if (twm == next - 1) {
 			pxdlock_t *pxdlock;
 
 			/* format a maplock for txUpdateMap() to update bmap

fs/jfs/jfs_xtree.c

@@ -3574,6 +3574,7 @@ s64 xtTruncate(tid_t tid, struct inode *ip, s64 newsize, int flag)
 				    min(index, (int)xtlck->lwm.offset) : index;
 				xtlck->lwm.length = index + 1 -
 				    xtlck->lwm.offset;
+				xtlck->twm.offset = index;
 				pxdlock = (pxdlock_t *) & xtlck->pxdlock;
 				pxdlock->flag = mlckFREEPXD;
 				PXDaddress(&pxdlock->pxd, xaddr);
@@ -3705,7 +3706,6 @@ s64 xtTruncate(tid_t tid, struct inode *ip, s64 newsize, int flag)
 				 */
 				tlck = txLock(tid, ip, mp, tlckXTREE);
 				xtlck = (xtlock_t *) & tlck->lock;
-				xtlck->twm.offset = index;
 				if (!(tlck->type & tlckTRUNCATE)) {
 					xtlck->hwm.offset =
 					    le16_to_cpu(p->header.
@@ -3782,7 +3782,6 @@ s64 xtTruncate(tid_t tid, struct inode *ip, s64 newsize, int flag)
 			 */
 			tlck = txLock(tid, ip, mp, tlckXTREE);
 			xtlck = (xtlock_t *) & tlck->lock;
-			xtlck->twm.offset = index;
 			xtlck->hwm.offset =
 			    le16_to_cpu(p->header.nextindex) - 1;
 			tlck->type = tlckXTREE | tlckFREE;
@@ -3989,11 +3988,10 @@ s64 xtTruncate_pmap(tid_t tid, struct inode *ip, s64 committed_size)
 		return  (xoff + xlen) << JFS_SBI(ip->i_sb)->l2bsize;
 	}
 	tlck = txLock(tid, ip, mp, tlckXTREE);
-	tlck->type = tlckXTREE | tlckTRUNCATE;
+	tlck->type = tlckXTREE | tlckFREE;
 	xtlck = (xtlock_t *) & tlck->lock;
 	xtlck->hwm.offset = index;
 
-	tlck->type = tlckXTREE | tlckFREE;
 
 	XT_PUTPAGE(mp);
 
@@ -4024,7 +4022,6 @@ s64 xtTruncate_pmap(tid_t tid, struct inode *ip, s64 committed_size)
 		 */
 		tlck = txLock(tid, ip, mp, tlckXTREE);
 		xtlck = (xtlock_t *) & tlck->lock;
-		xtlck->twm.offset = index;
 		xtlck->hwm.offset =
 		    le16_to_cpu(p->header.nextindex) - 1;
 		tlck->type = tlckXTREE | tlckFREE;