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rbd: implement watch/unwatch with new code 

Implement a new function to set up or tear down a watch event
for an mapped rbd image header using the new request code.

Create a new object request type "nodata" to handle this.  And
define rbd_osd_trivial_callback() which simply marks a request done.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-01-18 12:31:10 -06:00 committed by Sage Weil
parent 86ea43bfcb
commit 9969ebc5af
1 changed files with 86 additions and 3 deletions
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89
drivers/block/rbd.c
View File

@ -170,7 +170,9 @@ typedef void (*rbd_img_callback_t)(struct rbd_img_request *);
struct rbd_obj_request;
typedef void (*rbd_obj_callback_t)(struct rbd_obj_request *);
enum obj_request_type { OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES };
enum obj_request_type {
OBJ_REQUEST_NODATA, OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES
};
struct rbd_obj_request {
const char *object_name;
@ -1083,6 +1085,7 @@ static inline void rbd_img_obj_request_del(struct rbd_img_request *img_request,
static bool obj_request_type_valid(enum obj_request_type type)
{
switch (type) {
case OBJ_REQUEST_NODATA:
case OBJ_REQUEST_BIO:
case OBJ_REQUEST_PAGES:
return true;
@ -1306,6 +1309,12 @@ static int rbd_obj_request_wait(struct rbd_obj_request *obj_request)
return wait_for_completion_interruptible(&obj_request->completion);
}
static void rbd_osd_trivial_callback(struct rbd_obj_request *obj_request,
struct ceph_osd_op *op)
{
atomic_set(&obj_request->done, 1);
}
static void rbd_obj_request_complete(struct rbd_obj_request *obj_request)
{
if (obj_request->callback)
@ -1500,6 +1509,9 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
case CEPH_OSD_OP_WRITE:
rbd_osd_write_callback(obj_request, op);
break;
case CEPH_OSD_OP_WATCH:
rbd_osd_trivial_callback(obj_request, op);
break;
default:
rbd_warn(NULL, "%s: unsupported op %hu\n",
obj_request->object_name, (unsigned short) opcode);
@ -1543,6 +1555,8 @@ static struct ceph_osd_request *rbd_osd_req_create(
rbd_assert(obj_request_type_valid(obj_request->type));
switch (obj_request->type) {
case OBJ_REQUEST_NODATA:
break; /* Nothing to do */
case OBJ_REQUEST_BIO:
rbd_assert(obj_request->bio_list != NULL);
osd_req->r_bio = obj_request->bio_list;
@ -1635,6 +1649,8 @@ static void rbd_obj_request_destroy(struct kref *kref)
rbd_assert(obj_request_type_valid(obj_request->type));
switch (obj_request->type) {
case OBJ_REQUEST_NODATA:
break; /* Nothing to do */
case OBJ_REQUEST_BIO:
if (obj_request->bio_list)
bio_chain_put(obj_request->bio_list);
@ -1862,6 +1878,72 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request)
return 0;
}
/*
* Request sync osd watch/unwatch. The value of "start" determines
* whether a watch request is being initiated or torn down.
*/
static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)
{
struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
struct rbd_obj_request *obj_request;
struct ceph_osd_req_op *op;
int ret;
rbd_assert(start ^ !!rbd_dev->watch_event);
rbd_assert(start ^ !!rbd_dev->watch_request);
if (start) {
ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0, rbd_dev,
&rbd_dev->watch_event);
if (ret < 0)
return ret;
}
ret = -ENOMEM;
obj_request = rbd_obj_request_create(rbd_dev->header_name, 0, 0,
OBJ_REQUEST_NODATA);
if (!obj_request)
goto out_cancel;
op = rbd_osd_req_op_create(CEPH_OSD_OP_WATCH,
rbd_dev->watch_event->cookie,
rbd_dev->header.obj_version, start);
if (!op)
goto out_cancel;
obj_request->osd_req = rbd_osd_req_create(rbd_dev, true,
obj_request, op);
rbd_osd_req_op_destroy(op);
if (!obj_request->osd_req)
goto out_cancel;
if (start) {
rbd_dev->watch_request = obj_request->osd_req;
ceph_osdc_set_request_linger(osdc, rbd_dev->watch_request);
}
ret = rbd_obj_request_submit(osdc, obj_request);
if (ret)
goto out_cancel;
ret = rbd_obj_request_wait(obj_request);
if (ret)
goto out_cancel;
ret = obj_request->result;
if (ret)
goto out_cancel;
if (start)
goto done; /* Done if setting up the watch request */
out_cancel:
/* Cancel the event if we're tearing down, or on error */
ceph_osdc_cancel_event(rbd_dev->watch_event);
rbd_dev->watch_event = NULL;
done:
if (obj_request)
rbd_obj_request_put(obj_request);
return ret;
}
static void rbd_request_fn(struct request_queue *q)
{
struct rbd_device *rbd_dev = q->queuedata;
@ -3879,7 +3961,8 @@ static int rbd_dev_probe_finish(struct rbd_device *rbd_dev)
if (ret)
goto err_out_bus;
ret = rbd_req_sync_watch(rbd_dev, 1);
(void) rbd_req_sync_watch; /* avoid a warning */
ret = rbd_dev_header_watch_sync(rbd_dev, 1);
if (ret)
goto err_out_bus;
@ -4042,7 +4125,7 @@ static void rbd_dev_release(struct device *dev)
rbd_dev->watch_request);
}
if (rbd_dev->watch_event)
rbd_req_sync_watch(rbd_dev, 0);
rbd_dev_header_watch_sync(rbd_dev, 0);
/* clean up and free blkdev */
rbd_free_disk(rbd_dev);