rbd: new request handling code
The notable changes are: - instead of explicitly stat'ing the object to see if it exists before issuing the write, send the write optimistically along with the stat in a single OSD request - zero copyup optimization - all object requests are associated with an image request and have a valid ->img_request pointer; there are no standalone (!IMG_DATA) object requests anymore - code is structured as a state machine (vs a bunch of callbacks with implicit state) Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov
parent
45a267dbb4
commit
3da691bf43
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@ -235,11 +235,37 @@ enum obj_req_flags {
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OBJ_REQ_EXISTS, /* target exists: no = 0, yes = 1 */
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};
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/*
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* Writes go through the following state machine to deal with
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* layering:
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*
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* need copyup
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* RBD_OBJ_WRITE_GUARD ---------------> RBD_OBJ_WRITE_COPYUP
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* | ^ |
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* v \------------------------------/
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* done
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* ^
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* |
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* RBD_OBJ_WRITE_FLAT
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*
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* Writes start in RBD_OBJ_WRITE_GUARD or _FLAT, depending on whether
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* there is a parent or not.
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*/
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enum rbd_obj_write_state {
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RBD_OBJ_WRITE_FLAT = 1,
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RBD_OBJ_WRITE_GUARD,
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RBD_OBJ_WRITE_COPYUP,
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};
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struct rbd_obj_request {
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u64 object_no;
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u64 offset; /* object start byte */
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u64 length; /* bytes from offset */
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unsigned long flags;
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union {
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bool tried_parent; /* for reads */
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enum rbd_obj_write_state write_state; /* for writes */
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};
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/*
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* An object request associated with an image will have its
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@ -1282,6 +1308,27 @@ static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
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}));
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}
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/*
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* Zero a range in @obj_req data buffer defined by a bio (list) or
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* bio_vec array.
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*
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* @off is relative to the start of the data buffer.
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*/
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static void rbd_obj_zero_range(struct rbd_obj_request *obj_req, u32 off,
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u32 bytes)
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{
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switch (obj_req->type) {
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case OBJ_REQUEST_BIO:
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zero_bios(&obj_req->bio_pos, off, bytes);
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break;
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case OBJ_REQUEST_BVECS:
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zero_bvecs(&obj_req->bvec_pos, off, bytes);
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break;
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default:
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rbd_assert(0);
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}
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}
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/*
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* The default/initial value for all object request flags is 0. For
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* each flag, once its value is set to 1 it is never reset to 0
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@ -1567,6 +1614,35 @@ rbd_img_request_op_type(struct rbd_img_request *img_request)
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return OBJ_OP_READ;
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}
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static bool rbd_obj_is_entire(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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return !obj_req->offset &&
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obj_req->length == rbd_dev->layout.object_size;
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}
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static bool rbd_obj_is_tail(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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return obj_req->offset + obj_req->length ==
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rbd_dev->layout.object_size;
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}
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static bool rbd_img_is_write(struct rbd_img_request *img_req)
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{
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switch (rbd_img_request_op_type(img_req)) {
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case OBJ_OP_READ:
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return false;
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case OBJ_OP_WRITE:
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case OBJ_OP_DISCARD:
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return true;
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default:
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rbd_assert(0);
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}
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}
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static void
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rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
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{
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@ -1697,63 +1773,28 @@ static void rbd_osd_call_callback(struct rbd_obj_request *obj_request)
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obj_request_done_set(obj_request);
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}
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static void rbd_obj_handle_request(struct rbd_obj_request *obj_req);
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static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
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{
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struct rbd_obj_request *obj_request = osd_req->r_priv;
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u16 opcode;
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struct rbd_obj_request *obj_req = osd_req->r_priv;
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dout("%s: osd_req %p\n", __func__, osd_req);
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rbd_assert(osd_req == obj_request->osd_req);
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if (obj_request_img_data_test(obj_request)) {
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rbd_assert(obj_request->img_request);
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rbd_assert(obj_request->which != BAD_WHICH);
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} else {
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rbd_assert(obj_request->which == BAD_WHICH);
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}
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dout("%s osd_req %p result %d for obj_req %p\n", __func__, osd_req,
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osd_req->r_result, obj_req);
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rbd_assert(osd_req == obj_req->osd_req);
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if (osd_req->r_result < 0)
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obj_request->result = osd_req->r_result;
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obj_req->result = osd_req->r_result < 0 ? osd_req->r_result : 0;
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if (!obj_req->result && !rbd_img_is_write(obj_req->img_request))
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obj_req->xferred = osd_req->r_result;
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else
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/*
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* Writes aren't allowed to return a data payload. In some
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* guarded write cases (e.g. stat + zero on an empty object)
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* a stat response makes it through, but we don't care.
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*/
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obj_req->xferred = 0;
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/*
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* We support a 64-bit length, but ultimately it has to be
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* passed to the block layer, which just supports a 32-bit
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* length field.
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*/
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obj_request->xferred = osd_req->r_ops[0].outdata_len;
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rbd_assert(obj_request->xferred < (u64)UINT_MAX);
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opcode = osd_req->r_ops[0].op;
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switch (opcode) {
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case CEPH_OSD_OP_READ:
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rbd_osd_read_callback(obj_request);
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break;
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case CEPH_OSD_OP_SETALLOCHINT:
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rbd_assert(osd_req->r_ops[1].op == CEPH_OSD_OP_WRITE ||
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osd_req->r_ops[1].op == CEPH_OSD_OP_WRITEFULL);
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/* fall through */
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case CEPH_OSD_OP_WRITE:
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case CEPH_OSD_OP_WRITEFULL:
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rbd_osd_write_callback(obj_request);
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break;
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case CEPH_OSD_OP_STAT:
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rbd_osd_stat_callback(obj_request);
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break;
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case CEPH_OSD_OP_DELETE:
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case CEPH_OSD_OP_TRUNCATE:
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case CEPH_OSD_OP_ZERO:
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rbd_osd_discard_callback(obj_request);
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break;
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case CEPH_OSD_OP_CALL:
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rbd_osd_call_callback(obj_request);
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break;
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default:
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rbd_warn(NULL, "unexpected OSD op: object_no %016llx opcode %d",
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obj_request->object_no, opcode);
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break;
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}
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if (obj_request_done_test(obj_request))
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rbd_obj_request_complete(obj_request);
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rbd_obj_handle_request(obj_req);
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}
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static void rbd_osd_req_format_read(struct rbd_obj_request *obj_request)
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@ -1806,12 +1847,6 @@ err_req:
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return NULL;
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}
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/*
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* Create an osd request. A read request has one osd op (read).
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* A write request has either one (watch) or two (hint+write) osd ops.
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* (All rbd data writes are prefixed with an allocation hint op, but
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* technically osd watch is a write request, hence this distinction.)
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*/
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static struct ceph_osd_request *rbd_osd_req_create(
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struct rbd_device *rbd_dev,
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enum obj_operation_type op_type,
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@ -1831,8 +1866,6 @@ static struct ceph_osd_request *rbd_osd_req_create(
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snapc = img_request->snapc;
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}
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rbd_assert(num_ops == 1 || ((op_type == OBJ_OP_WRITE) && num_ops == 2));
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return __rbd_osd_req_create(rbd_dev, snapc, num_ops,
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(op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD) ?
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CEPH_OSD_FLAG_WRITE : CEPH_OSD_FLAG_READ, obj_request);
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@ -2251,6 +2284,211 @@ static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
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rbd_osd_req_format_read(obj_request);
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}
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static void rbd_osd_req_setup_data(struct rbd_obj_request *obj_req, u32 which)
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{
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switch (obj_req->type) {
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case OBJ_REQUEST_BIO:
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osd_req_op_extent_osd_data_bio(obj_req->osd_req, which,
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&obj_req->bio_pos,
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obj_req->length);
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break;
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case OBJ_REQUEST_BVECS:
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rbd_assert(obj_req->bvec_pos.iter.bi_size ==
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obj_req->length);
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osd_req_op_extent_osd_data_bvec_pos(obj_req->osd_req, which,
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&obj_req->bvec_pos);
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break;
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default:
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rbd_assert(0);
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}
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}
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static int rbd_obj_setup_read(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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obj_req->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1, obj_req);
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if (!obj_req->osd_req)
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return -ENOMEM;
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osd_req_op_extent_init(obj_req->osd_req, 0, CEPH_OSD_OP_READ,
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obj_req->offset, obj_req->length, 0, 0);
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rbd_osd_req_setup_data(obj_req, 0);
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rbd_osd_req_format_read(obj_req);
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return 0;
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}
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static int __rbd_obj_setup_stat(struct rbd_obj_request *obj_req,
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unsigned int which)
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{
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struct page **pages;
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/*
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* The response data for a STAT call consists of:
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* le64 length;
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* struct {
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* le32 tv_sec;
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* le32 tv_nsec;
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* } mtime;
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*/
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pages = ceph_alloc_page_vector(1, GFP_NOIO);
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if (IS_ERR(pages))
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return PTR_ERR(pages);
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osd_req_op_init(obj_req->osd_req, which, CEPH_OSD_OP_STAT, 0);
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osd_req_op_raw_data_in_pages(obj_req->osd_req, which, pages,
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8 + sizeof(struct ceph_timespec),
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0, false, true);
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return 0;
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}
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static void __rbd_obj_setup_write(struct rbd_obj_request *obj_req,
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unsigned int which)
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{
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struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
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u16 opcode;
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osd_req_op_alloc_hint_init(obj_req->osd_req, which++,
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rbd_dev->layout.object_size,
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rbd_dev->layout.object_size);
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if (rbd_obj_is_entire(obj_req))
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opcode = CEPH_OSD_OP_WRITEFULL;
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else
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opcode = CEPH_OSD_OP_WRITE;
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osd_req_op_extent_init(obj_req->osd_req, which, opcode,
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obj_req->offset, obj_req->length, 0, 0);
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rbd_osd_req_setup_data(obj_req, which++);
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rbd_assert(which == obj_req->osd_req->r_num_ops);
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rbd_osd_req_format_write(obj_req);
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}
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static int rbd_obj_setup_write(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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unsigned int num_osd_ops, which = 0;
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int ret;
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if (obj_request_overlaps_parent(obj_req)) {
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obj_req->write_state = RBD_OBJ_WRITE_GUARD;
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num_osd_ops = 3; /* stat + setallochint + write/writefull */
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} else {
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obj_req->write_state = RBD_OBJ_WRITE_FLAT;
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num_osd_ops = 2; /* setallochint + write/writefull */
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}
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obj_req->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_WRITE,
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num_osd_ops, obj_req);
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if (!obj_req->osd_req)
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return -ENOMEM;
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if (obj_request_overlaps_parent(obj_req)) {
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ret = __rbd_obj_setup_stat(obj_req, which++);
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if (ret)
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return ret;
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}
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__rbd_obj_setup_write(obj_req, which);
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return 0;
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}
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static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
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unsigned int which)
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{
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u16 opcode;
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if (rbd_obj_is_entire(obj_req)) {
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if (obj_request_overlaps_parent(obj_req)) {
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opcode = CEPH_OSD_OP_TRUNCATE;
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} else {
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osd_req_op_init(obj_req->osd_req, which++,
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CEPH_OSD_OP_DELETE, 0);
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opcode = 0;
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}
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} else if (rbd_obj_is_tail(obj_req)) {
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opcode = CEPH_OSD_OP_TRUNCATE;
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} else {
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opcode = CEPH_OSD_OP_ZERO;
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}
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if (opcode)
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osd_req_op_extent_init(obj_req->osd_req, which++, opcode,
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obj_req->offset, obj_req->length,
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0, 0);
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rbd_assert(which == obj_req->osd_req->r_num_ops);
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rbd_osd_req_format_write(obj_req);
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}
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static int rbd_obj_setup_discard(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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unsigned int num_osd_ops, which = 0;
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int ret;
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if (rbd_obj_is_entire(obj_req)) {
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obj_req->write_state = RBD_OBJ_WRITE_FLAT;
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num_osd_ops = 1; /* truncate/delete */
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} else {
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if (obj_request_overlaps_parent(obj_req)) {
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obj_req->write_state = RBD_OBJ_WRITE_GUARD;
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num_osd_ops = 2; /* stat + truncate/zero */
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} else {
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obj_req->write_state = RBD_OBJ_WRITE_FLAT;
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num_osd_ops = 1; /* truncate/zero */
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}
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}
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obj_req->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_DISCARD,
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num_osd_ops, obj_req);
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if (!obj_req->osd_req)
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return -ENOMEM;
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if (!rbd_obj_is_entire(obj_req) &&
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obj_request_overlaps_parent(obj_req)) {
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ret = __rbd_obj_setup_stat(obj_req, which++);
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if (ret)
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return ret;
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}
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__rbd_obj_setup_discard(obj_req, which);
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return 0;
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}
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/*
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* For each object request in @img_req, allocate an OSD request, add
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* individual OSD ops and prepare them for submission. The number of
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* OSD ops depends on op_type and the overlap point (if any).
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*/
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static int __rbd_img_fill_request(struct rbd_img_request *img_req)
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{
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struct rbd_obj_request *obj_req;
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int ret;
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for_each_obj_request(img_req, obj_req) {
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switch (rbd_img_request_op_type(img_req)) {
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case OBJ_OP_READ:
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ret = rbd_obj_setup_read(obj_req);
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break;
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case OBJ_OP_WRITE:
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ret = rbd_obj_setup_write(obj_req);
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break;
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case OBJ_OP_DISCARD:
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ret = rbd_obj_setup_discard(obj_req);
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break;
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default:
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rbd_assert(0);
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}
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if (ret)
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return ret;
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}
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return 0;
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}
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/*
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* Split up an image request into one or more object requests, each
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* to a different object. The "type" parameter indicates whether
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@ -2268,7 +2506,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
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struct rbd_obj_request *next_obj_request;
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struct ceph_bio_iter bio_it;
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struct ceph_bvec_iter bvec_it;
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enum obj_operation_type op_type;
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u64 img_offset;
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u64 resid;
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@ -2278,7 +2515,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
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img_offset = img_request->offset;
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resid = img_request->length;
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rbd_assert(resid > 0);
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op_type = rbd_img_request_op_type(img_request);
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||||
if (type == OBJ_REQUEST_BIO) {
|
||||
bio_it = *(struct ceph_bio_iter *)data_desc;
|
||||
|
|
@ -2289,7 +2525,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
|
|||
}
|
||||
|
||||
while (resid) {
|
||||
struct ceph_osd_request *osd_req;
|
||||
u64 object_no = img_offset >> rbd_dev->header.obj_order;
|
||||
u64 offset = rbd_segment_offset(rbd_dev, img_offset);
|
||||
u64 length = rbd_segment_length(rbd_dev, img_offset, resid);
|
||||
|
|
@ -2317,23 +2552,14 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
|
|||
ceph_bvec_iter_advance(&bvec_it, length);
|
||||
}
|
||||
|
||||
osd_req = rbd_osd_req_create(rbd_dev, op_type,
|
||||
(op_type == OBJ_OP_WRITE) ? 2 : 1,
|
||||
obj_request);
|
||||
if (!osd_req)
|
||||
goto out_unwind;
|
||||
|
||||
obj_request->osd_req = osd_req;
|
||||
obj_request->callback = rbd_img_obj_callback;
|
||||
obj_request->img_offset = img_offset;
|
||||
|
||||
rbd_img_obj_request_fill(obj_request, osd_req, op_type, 0);
|
||||
|
||||
img_offset += length;
|
||||
resid -= length;
|
||||
}
|
||||
|
||||
return 0;
|
||||
return __rbd_img_fill_request(img_request);
|
||||
|
||||
out_unwind:
|
||||
for_each_obj_request_safe(img_request, obj_request, next_obj_request)
|
||||
|
|
@ -2712,16 +2938,171 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request)
|
|||
|
||||
rbd_img_request_get(img_request);
|
||||
for_each_obj_request_safe(img_request, obj_request, next_obj_request) {
|
||||
ret = rbd_img_obj_request_submit(obj_request);
|
||||
if (ret)
|
||||
goto out_put_ireq;
|
||||
rbd_obj_request_submit(obj_request);
|
||||
}
|
||||
|
||||
out_put_ireq:
|
||||
rbd_img_request_put(img_request);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void rbd_img_end_child_request(struct rbd_img_request *img_req);
|
||||
|
||||
static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req,
|
||||
u64 img_offset, u32 bytes)
|
||||
{
|
||||
struct rbd_img_request *img_req = obj_req->img_request;
|
||||
struct rbd_img_request *child_img_req;
|
||||
int ret;
|
||||
|
||||
child_img_req = rbd_parent_request_create(obj_req, img_offset, bytes);
|
||||
if (!child_img_req)
|
||||
return -ENOMEM;
|
||||
|
||||
child_img_req->callback = rbd_img_end_child_request;
|
||||
|
||||
if (!rbd_img_is_write(img_req)) {
|
||||
switch (obj_req->type) {
|
||||
case OBJ_REQUEST_BIO:
|
||||
ret = rbd_img_request_fill(child_img_req,
|
||||
OBJ_REQUEST_BIO,
|
||||
&obj_req->bio_pos);
|
||||
break;
|
||||
case OBJ_REQUEST_BVECS:
|
||||
ret = rbd_img_request_fill(child_img_req,
|
||||
OBJ_REQUEST_BVECS,
|
||||
&obj_req->bvec_pos);
|
||||
break;
|
||||
default:
|
||||
rbd_assert(0);
|
||||
}
|
||||
} else {
|
||||
struct ceph_bvec_iter it = {
|
||||
.bvecs = obj_req->copyup_bvecs,
|
||||
.iter = { .bi_size = bytes },
|
||||
};
|
||||
|
||||
ret = rbd_img_request_fill(child_img_req, OBJ_REQUEST_BVECS,
|
||||
&it);
|
||||
}
|
||||
if (ret) {
|
||||
rbd_img_request_put(child_img_req);
|
||||
return ret;
|
||||
}
|
||||
|
||||
rbd_img_request_submit(child_img_req);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req)
|
||||
{
|
||||
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
|
||||
int ret;
|
||||
|
||||
if (obj_req->result == -ENOENT &&
|
||||
obj_req->img_offset < rbd_dev->parent_overlap &&
|
||||
!obj_req->tried_parent) {
|
||||
u64 obj_overlap = min(obj_req->length,
|
||||
rbd_dev->parent_overlap - obj_req->img_offset);
|
||||
|
||||
obj_req->tried_parent = true;
|
||||
ret = rbd_obj_read_from_parent(obj_req, obj_req->img_offset,
|
||||
obj_overlap);
|
||||
if (ret) {
|
||||
obj_req->result = ret;
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
/*
|
||||
* -ENOENT means a hole in the image -- zero-fill the entire
|
||||
* length of the request. A short read also implies zero-fill
|
||||
* to the end of the request. In both cases we update xferred
|
||||
* count to indicate the whole request was satisfied.
|
||||
*/
|
||||
if (obj_req->result == -ENOENT ||
|
||||
(!obj_req->result && obj_req->xferred < obj_req->length)) {
|
||||
rbd_assert(!obj_req->xferred || !obj_req->result);
|
||||
rbd_obj_zero_range(obj_req, obj_req->xferred,
|
||||
obj_req->length - obj_req->xferred);
|
||||
obj_req->result = 0;
|
||||
obj_req->xferred = obj_req->length;
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
/*
|
||||
* copyup_bvecs pages are never highmem pages
|
||||
*/
|
||||
static bool is_zero_bvecs(struct bio_vec *bvecs, u32 bytes)
|
||||
{
|
||||
struct ceph_bvec_iter it = {
|
||||
.bvecs = bvecs,
|
||||
.iter = { .bi_size = bytes },
|
||||
};
|
||||
|
||||
ceph_bvec_iter_advance_step(&it, bytes, ({
|
||||
if (memchr_inv(page_address(bv.bv_page) + bv.bv_offset, 0,
|
||||
bv.bv_len))
|
||||
return false;
|
||||
}));
|
||||
return true;
|
||||
}
|
||||
|
||||
static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
|
||||
{
|
||||
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
|
||||
unsigned int num_osd_ops = obj_req->osd_req->r_num_ops;
|
||||
|
||||
dout("%s obj_req %p bytes %u\n", __func__, obj_req, bytes);
|
||||
rbd_assert(obj_req->osd_req->r_ops[0].op == CEPH_OSD_OP_STAT);
|
||||
rbd_osd_req_destroy(obj_req->osd_req);
|
||||
|
||||
/*
|
||||
* Create a copyup request with the same number of OSD ops as
|
||||
* the original request. The original request was stat + op(s),
|
||||
* the new copyup request will be copyup + the same op(s).
|
||||
*/
|
||||
obj_req->osd_req = rbd_osd_req_create(rbd_dev,
|
||||
rbd_img_request_op_type(obj_req->img_request),
|
||||
num_osd_ops, obj_req);
|
||||
if (!obj_req->osd_req)
|
||||
return -ENOMEM;
|
||||
|
||||
/*
|
||||
* Only send non-zero copyup data to save some I/O and network
|
||||
* bandwidth -- zero copyup data is equivalent to the object not
|
||||
* existing.
|
||||
*/
|
||||
if (is_zero_bvecs(obj_req->copyup_bvecs, bytes)) {
|
||||
dout("%s obj_req %p detected zeroes\n", __func__, obj_req);
|
||||
bytes = 0;
|
||||
}
|
||||
|
||||
osd_req_op_cls_init(obj_req->osd_req, 0, CEPH_OSD_OP_CALL, "rbd",
|
||||
"copyup");
|
||||
osd_req_op_cls_request_data_bvecs(obj_req->osd_req, 0,
|
||||
obj_req->copyup_bvecs, bytes);
|
||||
|
||||
switch (rbd_img_request_op_type(obj_req->img_request)) {
|
||||
case OBJ_OP_WRITE:
|
||||
__rbd_obj_setup_write(obj_req, 1);
|
||||
break;
|
||||
case OBJ_OP_DISCARD:
|
||||
rbd_assert(!rbd_obj_is_entire(obj_req));
|
||||
__rbd_obj_setup_discard(obj_req, 1);
|
||||
break;
|
||||
default:
|
||||
rbd_assert(0);
|
||||
}
|
||||
|
||||
rbd_obj_request_submit(obj_req);
|
||||
/* FIXME: in lieu of rbd_img_obj_callback() */
|
||||
rbd_img_request_put(obj_req->img_request);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
|
||||
{
|
||||
u32 i;
|
||||
|
|
@ -2850,6 +3231,149 @@ out_err:
|
|||
obj_request_done_set(obj_request);
|
||||
}
|
||||
|
||||
static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
|
||||
{
|
||||
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
|
||||
u64 img_offset;
|
||||
u64 obj_overlap;
|
||||
int ret;
|
||||
|
||||
if (!obj_request_overlaps_parent(obj_req)) {
|
||||
/*
|
||||
* The overlap has become 0 (most likely because the
|
||||
* image has been flattened). Use rbd_obj_issue_copyup()
|
||||
* to re-submit the original write request -- the copyup
|
||||
* operation itself will be a no-op, since someone must
|
||||
* have populated the child object while we weren't
|
||||
* looking. Move to WRITE_FLAT state as we'll be done
|
||||
* with the operation once the null copyup completes.
|
||||
*/
|
||||
obj_req->write_state = RBD_OBJ_WRITE_FLAT;
|
||||
return rbd_obj_issue_copyup(obj_req, 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Determine the byte range covered by the object in the
|
||||
* child image to which the original request was to be sent.
|
||||
*/
|
||||
img_offset = obj_req->img_offset - obj_req->offset;
|
||||
obj_overlap = rbd_dev->layout.object_size;
|
||||
|
||||
/*
|
||||
* There is no defined parent data beyond the parent
|
||||
* overlap, so limit what we read at that boundary if
|
||||
* necessary.
|
||||
*/
|
||||
if (img_offset + obj_overlap > rbd_dev->parent_overlap) {
|
||||
rbd_assert(img_offset < rbd_dev->parent_overlap);
|
||||
obj_overlap = rbd_dev->parent_overlap - img_offset;
|
||||
}
|
||||
|
||||
ret = setup_copyup_bvecs(obj_req, obj_overlap);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
|
||||
return rbd_obj_read_from_parent(obj_req, img_offset, obj_overlap);
|
||||
}
|
||||
|
||||
static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req)
|
||||
{
|
||||
int ret;
|
||||
|
||||
again:
|
||||
switch (obj_req->write_state) {
|
||||
case RBD_OBJ_WRITE_GUARD:
|
||||
rbd_assert(!obj_req->xferred);
|
||||
if (obj_req->result == -ENOENT) {
|
||||
/*
|
||||
* The target object doesn't exist. Read the data for
|
||||
* the entire target object up to the overlap point (if
|
||||
* any) from the parent, so we can use it for a copyup.
|
||||
*/
|
||||
ret = rbd_obj_handle_write_guard(obj_req);
|
||||
if (ret) {
|
||||
obj_req->result = ret;
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
/* fall through */
|
||||
case RBD_OBJ_WRITE_FLAT:
|
||||
if (!obj_req->result)
|
||||
/*
|
||||
* There is no such thing as a successful short
|
||||
* write -- indicate the whole request was satisfied.
|
||||
*/
|
||||
obj_req->xferred = obj_req->length;
|
||||
return true;
|
||||
case RBD_OBJ_WRITE_COPYUP:
|
||||
obj_req->write_state = RBD_OBJ_WRITE_GUARD;
|
||||
if (obj_req->result)
|
||||
goto again;
|
||||
|
||||
rbd_assert(obj_req->xferred);
|
||||
ret = rbd_obj_issue_copyup(obj_req, obj_req->xferred);
|
||||
if (ret) {
|
||||
obj_req->result = ret;
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
default:
|
||||
rbd_assert(0);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Returns true if @obj_req is completed, or false otherwise.
|
||||
*/
|
||||
static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req)
|
||||
{
|
||||
switch (rbd_img_request_op_type(obj_req->img_request)) {
|
||||
case OBJ_OP_READ:
|
||||
return rbd_obj_handle_read(obj_req);
|
||||
case OBJ_OP_WRITE:
|
||||
return rbd_obj_handle_write(obj_req);
|
||||
case OBJ_OP_DISCARD:
|
||||
if (rbd_obj_handle_write(obj_req)) {
|
||||
/*
|
||||
* Hide -ENOENT from delete/truncate/zero -- discarding
|
||||
* a non-existent object is not a problem.
|
||||
*/
|
||||
if (obj_req->result == -ENOENT) {
|
||||
obj_req->result = 0;
|
||||
obj_req->xferred = obj_req->length;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
default:
|
||||
rbd_assert(0);
|
||||
}
|
||||
}
|
||||
|
||||
static void rbd_img_end_child_request(struct rbd_img_request *img_req)
|
||||
{
|
||||
struct rbd_obj_request *obj_req = img_req->obj_request;
|
||||
|
||||
rbd_assert(test_bit(IMG_REQ_CHILD, &img_req->flags));
|
||||
|
||||
obj_req->result = img_req->result;
|
||||
obj_req->xferred = img_req->xferred;
|
||||
rbd_img_request_put(img_req);
|
||||
|
||||
rbd_obj_handle_request(obj_req);
|
||||
}
|
||||
|
||||
static void rbd_obj_handle_request(struct rbd_obj_request *obj_req)
|
||||
{
|
||||
if (!__rbd_obj_handle_request(obj_req))
|
||||
return;
|
||||
|
||||
obj_request_done_set(obj_req);
|
||||
rbd_obj_request_complete(obj_req);
|
||||
}
|
||||
|
||||
static const struct rbd_client_id rbd_empty_cid;
|
||||
|
||||
static bool rbd_cid_equal(const struct rbd_client_id *lhs,
|
||||
|
|
|
|||
Loading…
Reference in New Issue