1 files changed, 36 insertions, 13 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 1410fa893653..739b372a5112 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -417,18 +417,20 @@ out_free_page:
 	return ret;
 }
 
-static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
+static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
+			int mode)
 {
 	/*
-	 * We use punch hole to reclaim the free space used by the
-	 * image a.k.a. discard. However we do not support discard if
-	 * encryption is enabled, because it may give an attacker
-	 * useful information.
+	 * We use fallocate to manipulate the space mappings used by the image
+	 * a.k.a. discard/zerorange. However we do not support this if
+	 * encryption is enabled, because it may give an attacker useful
+	 * information.
 	 */
 	struct file *file = lo->lo_backing_file;
-	int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
 	int ret;
 
+	mode |= FALLOC_FL_KEEP_SIZE;
+
 	if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) {
 		ret = -EOPNOTSUPP;
 		goto out;
@@ -596,9 +598,17 @@ 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:
-		return lo_discard(lo, rq, pos);
+		/*
+		 * If the caller doesn't want deallocation, call zeroout to
+		 * write zeroes the range.  Otherwise, punch them out.
+		 */
+		return lo_fallocate(lo, rq, pos,
+			(rq->cmd_flags & REQ_NOUNMAP) ?
+				FALLOC_FL_ZERO_RANGE :
+				FALLOC_FL_PUNCH_HOLE);
+	case REQ_OP_DISCARD:
+		return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
 	case REQ_OP_WRITE:
 		if (lo->transfer)
 			return lo_write_transfer(lo, rq, pos);
@@ -630,7 +640,9 @@ static void loop_reread_partitions(struct loop_device *lo,
 {
 	int rc;
 
-	rc = blkdev_reread_part(bdev);
+	mutex_lock(&bdev->bd_mutex);
+	rc = bdev_disk_changed(bdev, false);
+	mutex_unlock(&bdev->bd_mutex);
 	if (rc)
 		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
 			__func__, lo->lo_number, lo->lo_file_name, rc);
@@ -994,6 +1006,16 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
 		blk_queue_write_cache(lo->lo_queue, true, false);
 
+	if (io_is_direct(lo->lo_backing_file) && inode->i_sb->s_bdev) {
+		/* In case of direct I/O, match underlying block size */
+		unsigned short bsize = bdev_logical_block_size(
+			inode->i_sb->s_bdev);
+
+		blk_queue_logical_block_size(lo->lo_queue, bsize);
+		blk_queue_physical_block_size(lo->lo_queue, bsize);
+		blk_queue_io_min(lo->lo_queue, bsize);
+	}
+
 	loop_update_rotational(lo);
 	loop_update_dio(lo);
 	set_capacity(lo->lo_disk, size);
@@ -1144,10 +1166,11 @@ out_unlock:
 		 * must be at least one and it can only become zero when the
 		 * current holder is released.
 		 */
-		if (release)
-			err = __blkdev_reread_part(bdev);
-		else
-			err = blkdev_reread_part(bdev);
+		if (!release)
+			mutex_lock(&bdev->bd_mutex);
+		err = bdev_disk_changed(bdev, false);
+		if (!release)
+			mutex_unlock(&bdev->bd_mutex);
 		if (err)
 			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
 				__func__, lo_number, err);