rbd: handle DISCARD and WRITE_ZEROES separately

With discard_zeroes_data gone in commit 48920ff2a5 ("block: remove
the discard_zeroes_data flag"), continuing to provide this guarantee is
pointless: applications can't query it and discards can only be used
for deallocating.

Add OBJ_OP_ZEROOUT and move the existing logic under it.  As the first
step to divorcing OBJ_OP_DISCARD, stop worrying about copyups but keep
special casing whole-object layered discards.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
This commit is contained in:
Ilya Dryomov 2019-01-29 12:46:25 +01:00
parent fd7e3f0d8f
commit 6484cbe987

View file

@ -214,6 +214,7 @@ enum obj_operation_type {
OBJ_OP_READ = 1,
OBJ_OP_WRITE,
OBJ_OP_DISCARD,
OBJ_OP_ZEROOUT,
};
/*
@ -857,6 +858,8 @@ static char* obj_op_name(enum obj_operation_type op_type)
return "write";
case OBJ_OP_DISCARD:
return "discard";
case OBJ_OP_ZEROOUT:
return "zeroout";
default:
return "???";
}
@ -1419,6 +1422,7 @@ static bool rbd_img_is_write(struct rbd_img_request *img_req)
return false;
case OBJ_OP_WRITE:
case OBJ_OP_DISCARD:
case OBJ_OP_ZEROOUT:
return true;
default:
BUG();
@ -1841,7 +1845,40 @@ static int rbd_obj_setup_write(struct rbd_obj_request *obj_req)
return 0;
}
static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
static u16 truncate_or_zero_opcode(struct rbd_obj_request *obj_req)
{
return rbd_obj_is_tail(obj_req) ? CEPH_OSD_OP_TRUNCATE :
CEPH_OSD_OP_ZERO;
}
static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
{
int ret;
/* reverse map the entire object onto the parent */
ret = rbd_obj_calc_img_extents(obj_req, true);
if (ret)
return ret;
obj_req->osd_req = rbd_osd_req_create(obj_req, 1);
if (!obj_req->osd_req)
return -ENOMEM;
if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents) {
osd_req_op_init(obj_req->osd_req, 0, CEPH_OSD_OP_DELETE, 0);
} else {
osd_req_op_extent_init(obj_req->osd_req, 0,
truncate_or_zero_opcode(obj_req),
obj_req->ex.oe_off, obj_req->ex.oe_len,
0, 0);
}
obj_req->write_state = RBD_OBJ_WRITE_FLAT;
rbd_osd_req_format_write(obj_req);
return 0;
}
static void __rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req,
unsigned int which)
{
u16 opcode;
@ -1856,10 +1893,8 @@ static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
CEPH_OSD_OP_DELETE, 0);
opcode = 0;
}
} else if (rbd_obj_is_tail(obj_req)) {
opcode = CEPH_OSD_OP_TRUNCATE;
} else {
opcode = CEPH_OSD_OP_ZERO;
opcode = truncate_or_zero_opcode(obj_req);
}
if (opcode)
@ -1871,7 +1906,7 @@ static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
rbd_osd_req_format_write(obj_req);
}
static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
static int rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req)
{
unsigned int num_osd_ops, which = 0;
int ret;
@ -1907,7 +1942,7 @@ static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
return ret;
}
__rbd_obj_setup_discard(obj_req, which);
__rbd_obj_setup_zeroout(obj_req, which);
return 0;
}
@ -1932,6 +1967,9 @@ static int __rbd_img_fill_request(struct rbd_img_request *img_req)
case OBJ_OP_DISCARD:
ret = rbd_obj_setup_discard(obj_req);
break;
case OBJ_OP_ZEROOUT:
ret = rbd_obj_setup_zeroout(obj_req);
break;
default:
rbd_assert(0);
}
@ -2392,9 +2430,9 @@ static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
case OBJ_OP_WRITE:
__rbd_obj_setup_write(obj_req, 1);
break;
case OBJ_OP_DISCARD:
case OBJ_OP_ZEROOUT:
rbd_assert(!rbd_obj_is_entire(obj_req));
__rbd_obj_setup_discard(obj_req, 1);
__rbd_obj_setup_zeroout(obj_req, 1);
break;
default:
rbd_assert(0);
@ -2524,6 +2562,7 @@ static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req)
case OBJ_OP_WRITE:
return rbd_obj_handle_write(obj_req);
case OBJ_OP_DISCARD:
case OBJ_OP_ZEROOUT:
if (rbd_obj_handle_write(obj_req)) {
/*
* Hide -ENOENT from delete/truncate/zero -- discarding
@ -3636,9 +3675,11 @@ static void rbd_queue_workfn(struct work_struct *work)
switch (req_op(rq)) {
case REQ_OP_DISCARD:
case REQ_OP_WRITE_ZEROES:
op_type = OBJ_OP_DISCARD;
break;
case REQ_OP_WRITE_ZEROES:
op_type = OBJ_OP_ZEROOUT;
break;
case REQ_OP_WRITE:
op_type = OBJ_OP_WRITE;
break;
@ -3718,7 +3759,7 @@ static void rbd_queue_workfn(struct work_struct *work)
img_request->rq = rq;
snapc = NULL; /* img_request consumes a ref */
if (op_type == OBJ_OP_DISCARD)
if (op_type == OBJ_OP_DISCARD || op_type == OBJ_OP_ZEROOUT)
result = rbd_img_fill_nodata(img_request, offset, length);
else
result = rbd_img_fill_from_bio(img_request, offset, length,