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 <[email protected]>
---
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 5ac312f..2e6c103 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;
}
--
1.9.3
On 10/27/14 14:44, Vitaly Kuznetsov wrote:
> 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 <[email protected]>
> ---
> 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 5ac312f..2e6c103 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;
> }
>
>
Not sure if there has been some feedback yet (I can't see anything
threaded with this message in my inbox).
FWIW I consulted "Documentation/block/writeback_cache_control.txt" for
this review. Apparently, REQ_FLUSH forces out "previously completed
write requests", whereas REQ_FUA delays the IO completion signal for
*this* request until "the data has been committed to non-volatile
storage". So, indeed, support for REQ_FLUSH only does not guarantee that
REQ_FUA can be served.
Reviewed-by: Laszlo Ersek <[email protected]>
Thanks
Laszlo
On 11/03/2014 07:22 AM, Laszlo Ersek wrote:
> On 10/27/14 14:44, Vitaly Kuznetsov wrote:
>> 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 <[email protected]>
>> ---
>> 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 5ac312f..2e6c103 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)));
Somewhat unrelated to the patch, but I am wondering whether we actually
need flush_op field at all as it seems that it is unambiguously defined
by REQ_FLUSH/REQ_FUA.
-boris
>> }
>>
>> /*
>> @@ -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;
>> }
>>
>>
> Not sure if there has been some feedback yet (I can't see anything
> threaded with this message in my inbox).
>
> FWIW I consulted "Documentation/block/writeback_cache_control.txt" for
> this review. Apparently, REQ_FLUSH forces out "previously completed
> write requests", whereas REQ_FUA delays the IO completion signal for
> *this* request until "the data has been committed to non-volatile
> storage". So, indeed, support for REQ_FLUSH only does not guarantee that
> REQ_FUA can be served.
>
> Reviewed-by: Laszlo Ersek <[email protected]>
>
> Thanks
> Laszlo
Boris Ostrovsky <[email protected]> writes:
> On 11/03/2014 07:22 AM, Laszlo Ersek wrote:
>> On 10/27/14 14:44, Vitaly Kuznetsov wrote:
>>> 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 <[email protected]>
>>> ---
>>> 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 5ac312f..2e6c103 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)));
>
> Somewhat unrelated to the patch, but I am wondering whether we
> actually need flush_op field at all as it seems that it is
> unambiguously defined by REQ_FLUSH/REQ_FUA.
I was under an impression it was added for readability sake but we
definitely can remove it. If noone objects I'll send separate cleanup
patch (don't want to mix these two).
>
> -boris
>
>>> }
>>> /*
>>> @@ -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;
>>> }
>>>
>>>
>> Not sure if there has been some feedback yet (I can't see anything
>> threaded with this message in my inbox).
>>
>> FWIW I consulted "Documentation/block/writeback_cache_control.txt" for
>> this review. Apparently, REQ_FLUSH forces out "previously completed
>> write requests", whereas REQ_FUA delays the IO completion signal for
>> *this* request until "the data has been committed to non-volatile
>> storage". So, indeed, support for REQ_FLUSH only does not guarantee that
>> REQ_FUA can be served.
>>
>> Reviewed-by: Laszlo Ersek <[email protected]>
>>
>> Thanks
>> Laszlo
--
Vitaly
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 <[email protected]>
Reviewed-by: Laszlo Ersek <[email protected]>
---
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 5ac312f..2e6c103 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;
}
--
1.9.3
On 12/01/2014 08:01 AM, Vitaly Kuznetsov wrote:
> 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 <[email protected]>
> Reviewed-by: Laszlo Ersek <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
(although, as I mentioned last time, a companion patch to remove
flush_op would be a good thing to have)
-boris
> ---
> 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 5ac312f..2e6c103 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;
> }
>
Boris Ostrovsky <[email protected]> writes:
> On 12/01/2014 08:01 AM, Vitaly Kuznetsov wrote:
>> 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 <[email protected]>
>> Reviewed-by: Laszlo Ersek <[email protected]>
>
> Reviewed-by: Boris Ostrovsky <[email protected]>
>
> (although, as I mentioned last time, a companion patch to remove
> flush_op would be a good thing to have)
>
Thanks, it is on my todo list but I'm trying to separate this
(potential) bugfix from straight cleanup.
> -boris
>
>> ---
>> 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 5ac312f..2e6c103 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;
>> }
>>
--
Vitaly