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rbd: introduce copyup state machine

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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 2019-06-13 17:44:08 +02:00
parent ea9b743c97
commit 793333a303
1 changed files with 125 additions and 66 deletions
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191
drivers/block/rbd.c
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@ -226,6 +226,7 @@ enum obj_operation_type {
#define RBD_OBJ_FLAG_DELETION (1U << 0)
#define RBD_OBJ_FLAG_COPYUP_ENABLED (1U << 1)
#define RBD_OBJ_FLAG_COPYUP_ZEROS (1U << 2)
enum rbd_obj_read_state {
RBD_OBJ_READ_START = 1,
@ -261,9 +262,15 @@ enum rbd_obj_read_state {
enum rbd_obj_write_state {
RBD_OBJ_WRITE_START = 1,
RBD_OBJ_WRITE_OBJECT,
RBD_OBJ_WRITE_READ_FROM_PARENT,
RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC,
RBD_OBJ_WRITE_COPYUP_OPS,
__RBD_OBJ_WRITE_COPYUP,
RBD_OBJ_WRITE_COPYUP,
};
enum rbd_obj_copyup_state {
RBD_OBJ_COPYUP_START = 1,
RBD_OBJ_COPYUP_READ_PARENT,
__RBD_OBJ_COPYUP_WRITE_OBJECT,
RBD_OBJ_COPYUP_WRITE_OBJECT,
};
struct rbd_obj_request {
@ -286,12 +293,15 @@ struct rbd_obj_request {
u32 bvec_idx;
};
};
enum rbd_obj_copyup_state copyup_state;
struct bio_vec *copyup_bvecs;
u32 copyup_bvec_count;
struct list_head osd_reqs; /* w/ r_private_item */
struct mutex state_mutex;
struct pending_result pending;
struct kref kref;
};
@ -2568,8 +2578,8 @@ static bool is_zero_bvecs(struct bio_vec *bvecs, u32 bytes)
#define MODS_ONLY U32_MAX
static int rbd_obj_issue_copyup_empty_snapc(struct rbd_obj_request *obj_req,
u32 bytes)
static int rbd_obj_copyup_empty_snapc(struct rbd_obj_request *obj_req,
u32 bytes)
{
struct ceph_osd_request *osd_req;
int ret;
@ -2595,7 +2605,8 @@ static int rbd_obj_issue_copyup_empty_snapc(struct rbd_obj_request *obj_req,
return 0;
}
static int rbd_obj_issue_copyup_ops(struct rbd_obj_request *obj_req, u32 bytes)
static int rbd_obj_copyup_current_snapc(struct rbd_obj_request *obj_req,
u32 bytes)
{
struct ceph_osd_request *osd_req;
int num_ops = count_write_ops(obj_req);
@ -2628,33 +2639,6 @@ static int rbd_obj_issue_copyup_ops(struct rbd_obj_request *obj_req, u32 bytes)
return 0;
}
static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
{
/*
* 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;
}
if (obj_req->img_request->snapc->num_snaps && bytes > 0) {
/*
* Send a copyup request with an empty snapshot context to
* deep-copyup the object through all existing snapshots.
* A second request with the current snapshot context will be
* sent for the actual modification.
*/
obj_req->write_state = RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC;
return rbd_obj_issue_copyup_empty_snapc(obj_req, bytes);
}
obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
return rbd_obj_issue_copyup_ops(obj_req, bytes);
}
static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
{
u32 i;
@ -2688,7 +2672,7 @@ static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
* target object up to the overlap point (if any) from the parent,
* so we can use it for a copyup.
*/
static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
static int rbd_obj_copyup_read_parent(struct rbd_obj_request *obj_req)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
int ret;
@ -2703,22 +2687,111 @@ static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
* request -- pass MODS_ONLY since the copyup isn't needed
* anymore.
*/
obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
return rbd_obj_issue_copyup_ops(obj_req, MODS_ONLY);
return rbd_obj_copyup_current_snapc(obj_req, MODS_ONLY);
}
ret = setup_copyup_bvecs(obj_req, rbd_obj_img_extents_bytes(obj_req));
if (ret)
return ret;
obj_req->write_state = RBD_OBJ_WRITE_READ_FROM_PARENT;
return rbd_obj_read_from_parent(obj_req);
}
static void rbd_obj_copyup_write_object(struct rbd_obj_request *obj_req)
{
u32 bytes = rbd_obj_img_extents_bytes(obj_req);
int ret;
rbd_assert(!obj_req->pending.result && !obj_req->pending.num_pending);
/*
* 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 (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ZEROS)
bytes = 0;
if (obj_req->img_request->snapc->num_snaps && bytes > 0) {
/*
* Send a copyup request with an empty snapshot context to
* deep-copyup the object through all existing snapshots.
* A second request with the current snapshot context will be
* sent for the actual modification.
*/
ret = rbd_obj_copyup_empty_snapc(obj_req, bytes);
if (ret) {
obj_req->pending.result = ret;
return;
}
obj_req->pending.num_pending++;
bytes = MODS_ONLY;
}
ret = rbd_obj_copyup_current_snapc(obj_req, bytes);
if (ret) {
obj_req->pending.result = ret;
return;
}
obj_req->pending.num_pending++;
}
static bool rbd_obj_advance_copyup(struct rbd_obj_request *obj_req, int *result)
{
int ret;
again:
switch (obj_req->copyup_state) {
case RBD_OBJ_COPYUP_START:
rbd_assert(!*result);
ret = rbd_obj_copyup_read_parent(obj_req);
if (ret) {
*result = ret;
return true;
}
if (obj_req->num_img_extents)
obj_req->copyup_state = RBD_OBJ_COPYUP_READ_PARENT;
else
obj_req->copyup_state = RBD_OBJ_COPYUP_WRITE_OBJECT;
return false;
case RBD_OBJ_COPYUP_READ_PARENT:
if (*result)
return true;
if (is_zero_bvecs(obj_req->copyup_bvecs,
rbd_obj_img_extents_bytes(obj_req))) {
dout("%s %p detected zeros\n", __func__, obj_req);
obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ZEROS;
}
rbd_obj_copyup_write_object(obj_req);
if (!obj_req->pending.num_pending) {
*result = obj_req->pending.result;
obj_req->copyup_state = RBD_OBJ_COPYUP_WRITE_OBJECT;
goto again;
}
obj_req->copyup_state = __RBD_OBJ_COPYUP_WRITE_OBJECT;
return false;
case __RBD_OBJ_COPYUP_WRITE_OBJECT:
if (!pending_result_dec(&obj_req->pending, result))
return false;
/* fall through */
case RBD_OBJ_COPYUP_WRITE_OBJECT:
return true;
default:
BUG();
}
}
static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
int ret;
again:
switch (obj_req->write_state) {
case RBD_OBJ_WRITE_START:
rbd_assert(!*result);
@ -2733,12 +2806,10 @@ static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
case RBD_OBJ_WRITE_OBJECT:
if (*result == -ENOENT) {
if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
ret = rbd_obj_handle_write_guard(obj_req);
if (ret) {
*result = ret;
return true;
}
return false;
*result = 0;
obj_req->copyup_state = RBD_OBJ_COPYUP_START;
obj_req->write_state = __RBD_OBJ_WRITE_COPYUP;
goto again;
}
/*
* On a non-existent object:
@ -2747,31 +2818,19 @@ static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
if (obj_req->flags & RBD_OBJ_FLAG_DELETION)
*result = 0;
}
if (*result)
return true;
obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
goto again;
case __RBD_OBJ_WRITE_COPYUP:
if (!rbd_obj_advance_copyup(obj_req, result))
return false;
/* fall through */
case RBD_OBJ_WRITE_COPYUP_OPS:
case RBD_OBJ_WRITE_COPYUP:
if (*result)
rbd_warn(rbd_dev, "copyup failed: %d", *result);
return true;
case RBD_OBJ_WRITE_READ_FROM_PARENT:
if (*result)
return true;
ret = rbd_obj_issue_copyup(obj_req,
rbd_obj_img_extents_bytes(obj_req));
if (ret) {
*result = ret;
return true;
}
return false;
case RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC:
if (*result)
return true;
obj_req->write_state = RBD_OBJ_WRITE_COPYUP_OPS;
ret = rbd_obj_issue_copyup_ops(obj_req, MODS_ONLY);
if (ret) {
*result = ret;
return true;
}
return false;
default:
BUG();
}