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rbd: introduce copyup state machine
Both write and copyup paths will get more complex with object map. Factor copyup code out into a separate state machine. While at it, take advantage of obj_req->osd_reqs list and issue empty and current snapc OSD requests together, one after another. Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
This commit is contained in:
Ilya Dryomov
parent
ea9b743c97
commit
793333a303
@ -226,6 +226,7 @@ enum obj_operation_type {
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#define RBD_OBJ_FLAG_DELETION (1U << 0)
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#define RBD_OBJ_FLAG_COPYUP_ENABLED (1U << 1)
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#define RBD_OBJ_FLAG_COPYUP_ZEROS (1U << 2)
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enum rbd_obj_read_state {
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RBD_OBJ_READ_START = 1,
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@ -261,9 +262,15 @@ enum rbd_obj_read_state {
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enum rbd_obj_write_state {
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RBD_OBJ_WRITE_START = 1,
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RBD_OBJ_WRITE_OBJECT,
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RBD_OBJ_WRITE_READ_FROM_PARENT,
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RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC,
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RBD_OBJ_WRITE_COPYUP_OPS,
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__RBD_OBJ_WRITE_COPYUP,
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RBD_OBJ_WRITE_COPYUP,
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};
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enum rbd_obj_copyup_state {
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RBD_OBJ_COPYUP_START = 1,
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RBD_OBJ_COPYUP_READ_PARENT,
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__RBD_OBJ_COPYUP_WRITE_OBJECT,
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RBD_OBJ_COPYUP_WRITE_OBJECT,
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};
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struct rbd_obj_request {
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@ -286,12 +293,15 @@ struct rbd_obj_request {
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u32 bvec_idx;
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};
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};
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enum rbd_obj_copyup_state copyup_state;
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struct bio_vec *copyup_bvecs;
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u32 copyup_bvec_count;
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struct list_head osd_reqs; /* w/ r_private_item */
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struct mutex state_mutex;
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struct pending_result pending;
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struct kref kref;
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};
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@ -2568,8 +2578,8 @@ static bool is_zero_bvecs(struct bio_vec *bvecs, u32 bytes)
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#define MODS_ONLY U32_MAX
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static int rbd_obj_issue_copyup_empty_snapc(struct rbd_obj_request *obj_req,
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u32 bytes)
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static int rbd_obj_copyup_empty_snapc(struct rbd_obj_request *obj_req,
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u32 bytes)
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{
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struct ceph_osd_request *osd_req;
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int ret;
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@ -2595,7 +2605,8 @@ static int rbd_obj_issue_copyup_empty_snapc(struct rbd_obj_request *obj_req,
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return 0;
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}
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static int rbd_obj_issue_copyup_ops(struct rbd_obj_request *obj_req, u32 bytes)
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static int rbd_obj_copyup_current_snapc(struct rbd_obj_request *obj_req,
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u32 bytes)
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{
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struct ceph_osd_request *osd_req;
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int num_ops = count_write_ops(obj_req);
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@ -2628,33 +2639,6 @@ static int rbd_obj_issue_copyup_ops(struct rbd_obj_request *obj_req, u32 bytes)
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return 0;
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}
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static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
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{
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/*
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* Only send non-zero copyup data to save some I/O and network
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* bandwidth -- zero copyup data is equivalent to the object not
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* existing.
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*/
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if (is_zero_bvecs(obj_req->copyup_bvecs, bytes)) {
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dout("%s obj_req %p detected zeroes\n", __func__, obj_req);
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bytes = 0;
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}
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if (obj_req->img_request->snapc->num_snaps && bytes > 0) {
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/*
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* Send a copyup request with an empty snapshot context to
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* deep-copyup the object through all existing snapshots.
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* A second request with the current snapshot context will be
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* sent for the actual modification.
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*/
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obj_req->write_state = RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC;
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return rbd_obj_issue_copyup_empty_snapc(obj_req, bytes);
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}
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obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
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return rbd_obj_issue_copyup_ops(obj_req, bytes);
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}
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static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
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{
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u32 i;
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@ -2688,7 +2672,7 @@ static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
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* target object up to the overlap point (if any) from the parent,
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* so we can use it for a copyup.
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*/
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static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
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static int rbd_obj_copyup_read_parent(struct rbd_obj_request *obj_req)
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{
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struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
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int ret;
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@ -2703,22 +2687,111 @@ static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
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* request -- pass MODS_ONLY since the copyup isn't needed
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* anymore.
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*/
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obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
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return rbd_obj_issue_copyup_ops(obj_req, MODS_ONLY);
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return rbd_obj_copyup_current_snapc(obj_req, MODS_ONLY);
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}
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ret = setup_copyup_bvecs(obj_req, rbd_obj_img_extents_bytes(obj_req));
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if (ret)
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return ret;
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obj_req->write_state = RBD_OBJ_WRITE_READ_FROM_PARENT;
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return rbd_obj_read_from_parent(obj_req);
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}
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static void rbd_obj_copyup_write_object(struct rbd_obj_request *obj_req)
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{
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u32 bytes = rbd_obj_img_extents_bytes(obj_req);
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int ret;
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rbd_assert(!obj_req->pending.result && !obj_req->pending.num_pending);
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/*
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* Only send non-zero copyup data to save some I/O and network
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* bandwidth -- zero copyup data is equivalent to the object not
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* existing.
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*/
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if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ZEROS)
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bytes = 0;
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if (obj_req->img_request->snapc->num_snaps && bytes > 0) {
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/*
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* Send a copyup request with an empty snapshot context to
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* deep-copyup the object through all existing snapshots.
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* A second request with the current snapshot context will be
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* sent for the actual modification.
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*/
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ret = rbd_obj_copyup_empty_snapc(obj_req, bytes);
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if (ret) {
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obj_req->pending.result = ret;
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return;
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}
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obj_req->pending.num_pending++;
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bytes = MODS_ONLY;
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}
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ret = rbd_obj_copyup_current_snapc(obj_req, bytes);
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if (ret) {
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obj_req->pending.result = ret;
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return;
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}
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obj_req->pending.num_pending++;
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}
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static bool rbd_obj_advance_copyup(struct rbd_obj_request *obj_req, int *result)
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{
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int ret;
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again:
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switch (obj_req->copyup_state) {
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case RBD_OBJ_COPYUP_START:
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rbd_assert(!*result);
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ret = rbd_obj_copyup_read_parent(obj_req);
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if (ret) {
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*result = ret;
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return true;
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}
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if (obj_req->num_img_extents)
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obj_req->copyup_state = RBD_OBJ_COPYUP_READ_PARENT;
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else
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obj_req->copyup_state = RBD_OBJ_COPYUP_WRITE_OBJECT;
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return false;
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case RBD_OBJ_COPYUP_READ_PARENT:
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if (*result)
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return true;
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if (is_zero_bvecs(obj_req->copyup_bvecs,
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rbd_obj_img_extents_bytes(obj_req))) {
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dout("%s %p detected zeros\n", __func__, obj_req);
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obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ZEROS;
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}
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rbd_obj_copyup_write_object(obj_req);
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if (!obj_req->pending.num_pending) {
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*result = obj_req->pending.result;
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obj_req->copyup_state = RBD_OBJ_COPYUP_WRITE_OBJECT;
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goto again;
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}
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obj_req->copyup_state = __RBD_OBJ_COPYUP_WRITE_OBJECT;
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return false;
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case __RBD_OBJ_COPYUP_WRITE_OBJECT:
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if (!pending_result_dec(&obj_req->pending, result))
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return false;
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/* fall through */
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case RBD_OBJ_COPYUP_WRITE_OBJECT:
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return true;
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default:
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BUG();
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}
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}
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static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
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{
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struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
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int ret;
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again:
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switch (obj_req->write_state) {
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case RBD_OBJ_WRITE_START:
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rbd_assert(!*result);
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@ -2733,12 +2806,10 @@ static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
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case RBD_OBJ_WRITE_OBJECT:
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if (*result == -ENOENT) {
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if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
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ret = rbd_obj_handle_write_guard(obj_req);
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if (ret) {
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*result = ret;
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return true;
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}
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return false;
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*result = 0;
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obj_req->copyup_state = RBD_OBJ_COPYUP_START;
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obj_req->write_state = __RBD_OBJ_WRITE_COPYUP;
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goto again;
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}
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/*
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* On a non-existent object:
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@ -2747,31 +2818,19 @@ static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
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if (obj_req->flags & RBD_OBJ_FLAG_DELETION)
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*result = 0;
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}
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if (*result)
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return true;
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obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
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goto again;
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case __RBD_OBJ_WRITE_COPYUP:
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if (!rbd_obj_advance_copyup(obj_req, result))
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return false;
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/* fall through */
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case RBD_OBJ_WRITE_COPYUP_OPS:
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case RBD_OBJ_WRITE_COPYUP:
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if (*result)
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rbd_warn(rbd_dev, "copyup failed: %d", *result);
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return true;
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case RBD_OBJ_WRITE_READ_FROM_PARENT:
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if (*result)
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return true;
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ret = rbd_obj_issue_copyup(obj_req,
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rbd_obj_img_extents_bytes(obj_req));
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if (ret) {
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*result = ret;
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return true;
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}
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return false;
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case RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC:
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if (*result)
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return true;
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obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
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ret = rbd_obj_issue_copyup_ops(obj_req, MODS_ONLY);
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if (ret) {
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*result = ret;
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return true;
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}
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return false;
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default:
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BUG();
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}
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