diff options
| -rw-r--r-- | block/blk-barrier.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/block/blk-barrier.c b/block/blk-barrier.c index eefbde835308..557f69360b6a 100644 --- a/block/blk-barrier.c +++ b/block/blk-barrier.c @@ -310,6 +310,15 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, if (!q) return -ENXIO; + /* + * some block devices may not have their queue correctly set up here + * (e.g. loop device without a backing file) and so issuing a flush + * here will panic. Ensure there is a request function before issuing + * the barrier. + */ + if (!q->make_request_fn) + return -ENXIO; + bio = bio_alloc(gfp_mask, 0); bio->bi_end_io = bio_end_empty_barrier; bio->bi_bdev = bdev; |