rbd: fix I/O error propagation for reads (17c1cc1d) · Commits · 戴 / test

When a request returns an error, the driver needs to report the entire extent of the request as completed. Writes already did this, since they always set xferred = length, but reads were skipping that step if an error other than -ENOENT occurred. Instead, rbd would end up passing 0 xferred to blk_end_request(), which would always report needing more data. This resulted in an assert failing when more data was required by the block layer, but all the object requests were done: [ 1868.719077] rbd: obj_request read result -108 xferred 0 [ 1868.719077] [ 1868.719518] end_request: I/O error, dev rbd1, sector 0 [ 1868.719739] [ 1868.719739] Assertion failure in rbd_img_obj_callback() at line 1736: [ 1868.719739] [ 1868.719739] rbd_assert(more ^ (which == img_request->obj_request_count)); Without this assert, reads that hit errors would hang forever, since the block layer considered them incomplete. Fixes: http://tracker.ceph.com/issues/5647 CC: stable@vger.kernel.org # v3.10 Signed-off-by:

Josh Durgin <josh.durgin@inktank.com> Reviewed-by:

Alex Elder <alex.elder@linaro.org>

drivers/block/rbd.c

+7 −7

Original line number	Diff line number	Diff line
		@@ -1557,11 +1557,12 @@ rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
		obj_request, obj_request->img_request, obj_request->result,
		xferred, length);
		/*
		* ENOENT means a hole in the image. We zero-fill the
		* entire length of the request. A short read also implies
		* zero-fill to the end of the request. Either way we
		* update the xferred count to indicate the whole request
		* was satisfied.
		* ENOENT means a hole in the image. We zero-fill the entire
		* length of the request. A short read also implies zero-fill
		* to the end of the request. An error requires the whole
		* length of the request to be reported finished with an error
		* to the block layer. In each case we update the xferred
		* count to indicate the whole request was satisfied.
		*/
		rbd_assert(obj_request->type != OBJ_REQUEST_NODATA);
		if (obj_request->result == -ENOENT) {
		@@ -1570,14 +1571,13 @@ rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
		else
		zero_pages(obj_request->pages, 0, length);
		obj_request->result = 0;
		obj_request->xferred = length;
		} else if (xferred < length && !obj_request->result) {
		if (obj_request->type == OBJ_REQUEST_BIO)
		zero_bio_chain(obj_request->bio_list, xferred);
		else
		zero_pages(obj_request->pages, xferred, length);
		obj_request->xferred = length;
		}
		obj_request->xferred = length;
		obj_request_done_set(obj_request);
		}

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