On 06/25/2014 12:16 PM, Ilya Dryomov wrote:
> Introduce ceph_osdc_cancel_request() intended for canceling requests
> from the higher layers (rbd and cephfs). Because higher layers are in
> charge and are supposed to know what and when they are canceling, the
> request is not completed, only unref'ed and removed from the libceph
> data structures.
This seems reasonable.
But you make two changes here that I'd like to see a little
more explanation on. They seem significant enough to warrant
a little more attention in the commit description.
- __cancel_request() is no longer called when
ceph_osdc_wait_request() fails due to an
an interrupt. This is my main concern, and I
plan to work through it but I'm in a small hurry
right now.
- __unregister_linger_request() is now called when
a request is canceled, but it wasn't before. (Since
we're consistent about setting the r_linger flag
this should be fine, but it *is* a behavior change.)
I'm going to keep looking at this; I have about
20 minutes before I have to leave for a while.
-Alex
> Signed-off-by: Ilya Dryomov <[email protected]>
> ---
> include/linux/ceph/osd_client.h | 1 +
> net/ceph/osd_client.c | 31 +++++++++++++++++++++++++------
> 2 files changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
> index a8d5652f589d..de09cad7b7c7 100644
> --- a/include/linux/ceph/osd_client.h
> +++ b/include/linux/ceph/osd_client.h
> @@ -334,6 +334,7 @@ extern void ceph_osdc_put_request(struct ceph_osd_request
> *req);
> extern int ceph_osdc_start_request(struct ceph_osd_client *osdc,
> struct ceph_osd_request *req,
> bool nofail);
> +extern void ceph_osdc_cancel_request(struct ceph_osd_request *req);
> extern int ceph_osdc_wait_request(struct ceph_osd_client *osdc,
> struct ceph_osd_request *req);
> extern void ceph_osdc_sync(struct ceph_osd_client *osdc);
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index 8104db24bc09..ef44cc0bbc6a 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -2470,6 +2470,25 @@ int ceph_osdc_start_request(struct ceph_osd_client
> *osdc,
> EXPORT_SYMBOL(ceph_osdc_start_request);
>
> /*
> + * Unregister a registered request. The request is not completed (i.e.
> + * no callbacks or wakeups) - higher layers are supposed to know what
> + * they are canceling.
> + */
> +void ceph_osdc_cancel_request(struct ceph_osd_request *req)
> +{
> + struct ceph_osd_client *osdc = req->r_osdc;
> +
> + mutex_lock(&osdc->request_mutex);
> + if (req->r_linger)
> + __unregister_linger_request(osdc, req);
> + __unregister_request(osdc, req);
> + mutex_unlock(&osdc->request_mutex);
> +
> + dout("%s %p tid %llu canceled\n", __func__, req, req->r_tid);
> +}
> +EXPORT_SYMBOL(ceph_osdc_cancel_request);
> +
> +/*
> * wait for a request to complete
> */
> int ceph_osdc_wait_request(struct ceph_osd_client *osdc,
> @@ -2477,18 +2496,18 @@ int ceph_osdc_wait_request(struct ceph_osd_client
> *osdc,
> {
> int rc;
>
> + dout("%s %p tid %llu\n", __func__, req, req->r_tid);
> +
> rc = wait_for_completion_interruptible(&req->r_completion);
> if (rc < 0) {
> - mutex_lock(&osdc->request_mutex);
> - __cancel_request(req);
> - __unregister_request(osdc, req);
> - mutex_unlock(&osdc->request_mutex);
> + dout("%s %p tid %llu interrupted\n", __func__, req, req->r_tid);
> + ceph_osdc_cancel_request(req);
> complete_request(req);
> - dout("wait_request tid %llu canceled/timed out\n", req->r_tid);
> return rc;
> }
>
> - dout("wait_request tid %llu result %d\n", req->r_tid, req->r_result);
> + dout("%s %p tid %llu result %d\n", __func__, req, req->r_tid,
> + req->r_result);
> return req->r_result;
> }
> EXPORT_SYMBOL(ceph_osdc_wait_request);
>
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