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 Signed-off-by: Josh Durgin <[email protected]> --- drivers/block/rbd.c | 14 +++++++------- 1 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 0d669ae..f8fd7d3 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -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); } -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
