From ad42d391ae388bd4ce4d53e8d7b4089cfdcba411 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 1 Dec 2014 14:01:13 +0100 Subject: [PATCH] xen/blkfront: improve protection against issuing unsupported REQ_FUA Guard against issuing unsupported REQ_FUA and REQ_FLUSH was introduced in d11e61583 and was factored out into blkif_request_flush_valid() in 0f1ca65ee. However: 1) This check in incomplete. In case we negotiated to feature_flush = REQ_FLUSH and flush_op = BLKIF_OP_FLUSH_DISKCACHE (so FUA is unsupported) FUA request will still pass the check. 2) blkif_request_flush_valid() is misnamed. It is bool but returns true when the request is invalid. 3) When blkif_request_flush_valid() fails -EIO is being returned. It seems that -EOPNOTSUPP is more appropriate here. Fix all of the above issues. This patch is based on the original patch by Laszlo Ersek and a comment by Jeff Moyer. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Laszlo Ersek Reviewed-by: Boris Ostrovsky Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkfront.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 5ac312f6e0be..2e6c10371b24 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -582,12 +582,14 @@ static inline void flush_requests(struct blkfront_info *info) notify_remote_via_irq(info->irq); } -static inline bool blkif_request_flush_valid(struct request *req, - struct blkfront_info *info) +static inline bool blkif_request_flush_invalid(struct request *req, + struct blkfront_info *info) { return ((req->cmd_type != REQ_TYPE_FS) || - ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) && - !info->flush_op)); + ((req->cmd_flags & REQ_FLUSH) && + !(info->feature_flush & REQ_FLUSH)) || + ((req->cmd_flags & REQ_FUA) && + !(info->feature_flush & REQ_FUA))); } /* @@ -612,8 +614,8 @@ static void do_blkif_request(struct request_queue *rq) blk_start_request(req); - if (blkif_request_flush_valid(req, info)) { - __blk_end_request_all(req, -EIO); + if (blkif_request_flush_invalid(req, info)) { + __blk_end_request_all(req, -EOPNOTSUPP); continue; }