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xen/blkfront: improve protection against issuing unsupported REQ_FUA

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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 <vkuznets@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Vitaly Kuznetsov 2014-12-01 14:01:13 +01:00 committed by Konrad Rzeszutek Wilk
parent 9af8785a38
commit ad42d391ae
1 changed files with 8 additions and 6 deletions
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14
drivers/block/xen-blkfront.c
View file

@ -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;
}