@@ -441,6 +441,28 @@ static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
return ret;
}
+static int lo_zeroout(struct loop_device *lo, struct request *rq, loff_t pos)
+{
+ struct file *file = lo->lo_backing_file;
+ int mode = FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE;
+ int ret;
+
+ /*
+ * Ask the fs to zero out the blocks, which is supposed to result in
+ * space being allocated to the file.
+ */
+ if (!file->f_op->fallocate) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
+ if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
+ ret = -EIO;
+ out:
+ return ret;
+}
+
static int lo_req_flush(struct loop_device *lo, struct request *rq)
{
struct file *file = lo->lo_backing_file;
@@ -596,8 +618,15 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
switch (req_op(rq)) {
case REQ_OP_FLUSH:
return lo_req_flush(lo, rq);
- case REQ_OP_DISCARD:
case REQ_OP_WRITE_ZEROES:
+ /*
+ * If the caller doesn't want deallocation, call zeroout to
+ * write zeroes the range. Otherwise, punch them out.
+ */
+ if (rq->cmd_flags & REQ_NOUNMAP)
+ return lo_zeroout(lo, rq, pos);
+ /* fall through */
+ case REQ_OP_DISCARD:
return lo_discard(lo, rq, pos);
case REQ_OP_WRITE:
if (lo->transfer)