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authorDave Chinner <dchinner@redhat.com>2010-07-13 03:50:50 -0400
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 12:26:29 -0400
commitf10d9f617a65905c556c3b37c9b9646ae7d04ed7 (patch)
tree0e1d1a28578e8c1b2115b8486add3b235f7e3619 /block/blk-barrier.c
parent2669b19fa4debcdd6a660ace1a124c0900f113e6 (diff)
blkdev: check for valid request queue before issuing flush
Issuing a blkdev_issue_flush() on an unconfigured loop device causes a panic as q->make_request_fn is not configured. This can occur when trying to mount the unconfigured loop device as an XFS filesystem. There are no guards that catch the bio before the request function is called because we don't add a payload to the bio. Instead, manually check this case as soon as we have a pointer to the queue to flush. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block/blk-barrier.c')
-rw-r--r--block/blk-barrier.c9
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,
310 if (!q) 310 if (!q)
311 return -ENXIO; 311 return -ENXIO;
312 312
313 /*
314 * some block devices may not have their queue correctly set up here
315 * (e.g. loop device without a backing file) and so issuing a flush
316 * here will panic. Ensure there is a request function before issuing
317 * the barrier.
318 */
319 if (!q->make_request_fn)
320 return -ENXIO;
321
313 bio = bio_alloc(gfp_mask, 0); 322 bio = bio_alloc(gfp_mask, 0);
314 bio->bi_end_io = bio_end_empty_barrier; 323 bio->bi_end_io = bio_end_empty_barrier;
315 bio->bi_bdev = bdev; 324 bio->bi_bdev = bdev;