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rbd: get rid of obj_req->xferred, obj_req->result and img_req->xferred
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obj_req->xferred and img_req->xferred don't bring any value.  The
former is used for short reads and has to be set to obj_req->ex.oe_len
after that and elsewhere.  The latter is just an aggregate.

Use result for short reads (>=0 - number of bytes read, <0 - error) and
pass it around explicitly.  No need to store it in obj_req.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
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Ilya Dryomov committed Jul 8, 2019
1 parent 2635053 commit 54ab3b2
Showing 1 changed file with 58 additions and 91 deletions.
149 changes: 58 additions & 91 deletions drivers/block/rbd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -276,9 +276,6 @@ struct rbd_obj_request {

struct ceph_osd_request *osd_req;

u64 xferred; /* bytes transferred */
int result;

struct kref kref;
};

Expand All @@ -301,7 +298,6 @@ struct rbd_img_request {
struct rbd_obj_request *obj_request; /* obj req initiator */
};
spinlock_t completion_lock;
u64 xferred;/* aggregate bytes transferred */
int result; /* first nonzero obj_request result */

struct list_head object_extents; /* obj_req.ex structs */
Expand Down Expand Up @@ -584,6 +580,8 @@ static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
u64 *snap_features);

static void rbd_obj_handle_request(struct rbd_obj_request *obj_req, int result);

static int rbd_open(struct block_device *bdev, fmode_t mode)
{
struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
Expand Down Expand Up @@ -1317,6 +1315,8 @@ static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
static void rbd_obj_zero_range(struct rbd_obj_request *obj_req, u32 off,
u32 bytes)
{
dout("%s %p data buf %u~%u\n", __func__, obj_req, off, bytes);

switch (obj_req->img_request->data_type) {
case OBJ_REQUEST_BIO:
zero_bios(&obj_req->bio_pos, off, bytes);
Expand Down Expand Up @@ -1457,28 +1457,26 @@ static bool rbd_img_is_write(struct rbd_img_request *img_req)
}
}

static void rbd_obj_handle_request(struct rbd_obj_request *obj_req);

static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
{
struct rbd_obj_request *obj_req = osd_req->r_priv;
int result;

dout("%s osd_req %p result %d for obj_req %p\n", __func__, osd_req,
osd_req->r_result, obj_req);
rbd_assert(osd_req == obj_req->osd_req);

obj_req->result = osd_req->r_result < 0 ? osd_req->r_result : 0;
if (!obj_req->result && !rbd_img_is_write(obj_req->img_request))
obj_req->xferred = osd_req->r_result;
/*
* Writes aren't allowed to return a data payload. In some
* guarded write cases (e.g. stat + zero on an empty object)
* a stat response makes it through, but we don't care.
*/
if (osd_req->r_result > 0 && rbd_img_is_write(obj_req->img_request))
result = 0;
else
/*
* Writes aren't allowed to return a data payload. In some
* guarded write cases (e.g. stat + zero on an empty object)
* a stat response makes it through, but we don't care.
*/
obj_req->xferred = 0;
result = osd_req->r_result;

rbd_obj_handle_request(obj_req);
rbd_obj_handle_request(obj_req, result);
}

static void rbd_osd_req_format_read(struct rbd_obj_request *obj_request)
Expand Down Expand Up @@ -2041,7 +2039,6 @@ static int __rbd_img_fill_request(struct rbd_img_request *img_req)
if (ret < 0)
return ret;
if (ret > 0) {
img_req->xferred += obj_req->ex.oe_len;
img_req->pending_count--;
rbd_img_obj_request_del(img_req, obj_req);
continue;
Expand Down Expand Up @@ -2400,25 +2397,25 @@ static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req)
return 0;
}

static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req)
static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req, int *result)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
int ret;

if (obj_req->result == -ENOENT &&
if (*result == -ENOENT &&
rbd_dev->parent_overlap && !obj_req->tried_parent) {
/* reverse map this object extent onto the parent */
ret = rbd_obj_calc_img_extents(obj_req, false);
if (ret) {
obj_req->result = ret;
*result = ret;
return true;
}

if (obj_req->num_img_extents) {
obj_req->tried_parent = true;
ret = rbd_obj_read_from_parent(obj_req);
if (ret) {
obj_req->result = ret;
*result = ret;
return true;
}
return false;
Expand All @@ -2428,16 +2425,18 @@ static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req)
/*
* -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.
* to the end of the request.
*/
if (obj_req->result == -ENOENT ||
(!obj_req->result && obj_req->xferred < obj_req->ex.oe_len)) {
rbd_assert(!obj_req->xferred || !obj_req->result);
rbd_obj_zero_range(obj_req, obj_req->xferred,
obj_req->ex.oe_len - obj_req->xferred);
obj_req->result = 0;
obj_req->xferred = obj_req->ex.oe_len;
if (*result == -ENOENT) {
rbd_obj_zero_range(obj_req, 0, obj_req->ex.oe_len);
*result = 0;
} else if (*result >= 0) {
if (*result < obj_req->ex.oe_len)
rbd_obj_zero_range(obj_req, *result,
obj_req->ex.oe_len - *result);
else
rbd_assert(*result == obj_req->ex.oe_len);
*result = 0;
}

return true;
Expand Down Expand Up @@ -2635,56 +2634,48 @@ static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
return rbd_obj_read_from_parent(obj_req);
}

static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req)
static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req, int *result)
{
int ret;

switch (obj_req->write_state) {
case RBD_OBJ_WRITE_GUARD:
rbd_assert(!obj_req->xferred);
if (obj_req->result == -ENOENT) {
if (*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;
*result = ret;
return true;
}
return false;
}
/* fall through */
case RBD_OBJ_WRITE_FLAT:
case RBD_OBJ_WRITE_COPYUP_OPS:
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->ex.oe_len;
return true;
case RBD_OBJ_WRITE_READ_FROM_PARENT:
if (obj_req->result)
if (*result < 0)
return true;

rbd_assert(obj_req->xferred);
ret = rbd_obj_issue_copyup(obj_req, obj_req->xferred);
rbd_assert(*result);
ret = rbd_obj_issue_copyup(obj_req, *result);
if (ret) {
obj_req->result = ret;
obj_req->xferred = 0;
*result = ret;
return true;
}
return false;
case RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC:
if (obj_req->result)
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) {
obj_req->result = ret;
*result = ret;
return true;
}
return false;
Expand All @@ -2696,24 +2687,23 @@ static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req)
/*
* Returns true if @obj_req is completed, or false otherwise.
*/
static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req)
static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req,
int *result)
{
switch (obj_req->img_request->op_type) {
case OBJ_OP_READ:
return rbd_obj_handle_read(obj_req);
return rbd_obj_handle_read(obj_req, result);
case OBJ_OP_WRITE:
return rbd_obj_handle_write(obj_req);
return rbd_obj_handle_write(obj_req, result);
case OBJ_OP_DISCARD:
case OBJ_OP_ZEROOUT:
if (rbd_obj_handle_write(obj_req)) {
if (rbd_obj_handle_write(obj_req, result)) {
/*
* 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->ex.oe_len;
}
if (*result == -ENOENT)
*result = 0;
return true;
}
return false;
Expand All @@ -2722,76 +2712,53 @@ static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req)
}
}

static void rbd_obj_end_request(struct rbd_obj_request *obj_req)
static void rbd_obj_end_request(struct rbd_obj_request *obj_req, int result)
{
struct rbd_img_request *img_req = obj_req->img_request;

rbd_assert((!obj_req->result &&
obj_req->xferred == obj_req->ex.oe_len) ||
(obj_req->result < 0 && !obj_req->xferred));
if (!obj_req->result) {
img_req->xferred += obj_req->xferred;
rbd_assert(result <= 0);
if (!result)
return;
}

rbd_warn(img_req->rbd_dev,
"%s at objno %llu %llu~%llu result %d xferred %llu",
rbd_warn(img_req->rbd_dev, "%s at objno %llu %llu~%llu result %d",
obj_op_name(img_req->op_type), obj_req->ex.oe_objno,
obj_req->ex.oe_off, obj_req->ex.oe_len, obj_req->result,
obj_req->xferred);
if (!img_req->result) {
img_req->result = obj_req->result;
img_req->xferred = 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));
rbd_assert((!img_req->result &&
img_req->xferred == rbd_obj_img_extents_bytes(obj_req)) ||
(img_req->result < 0 && !img_req->xferred));

obj_req->result = img_req->result;
obj_req->xferred = img_req->xferred;
rbd_img_request_put(img_req);
obj_req->ex.oe_off, obj_req->ex.oe_len, result);
if (!img_req->result)
img_req->result = result;
}

static void rbd_img_end_request(struct rbd_img_request *img_req)
{
rbd_assert(!test_bit(IMG_REQ_CHILD, &img_req->flags));
rbd_assert((!img_req->result &&
img_req->xferred == blk_rq_bytes(img_req->rq)) ||
(img_req->result < 0 && !img_req->xferred));

blk_mq_end_request(img_req->rq,
errno_to_blk_status(img_req->result));
rbd_img_request_put(img_req);
}

static void rbd_obj_handle_request(struct rbd_obj_request *obj_req)
static void rbd_obj_handle_request(struct rbd_obj_request *obj_req, int result)
{
struct rbd_img_request *img_req;

again:
if (!__rbd_obj_handle_request(obj_req))
if (!__rbd_obj_handle_request(obj_req, &result))
return;

img_req = obj_req->img_request;
spin_lock(&img_req->completion_lock);
rbd_obj_end_request(obj_req);
rbd_obj_end_request(obj_req, result);
rbd_assert(img_req->pending_count);
if (--img_req->pending_count) {
spin_unlock(&img_req->completion_lock);
return;
}

spin_unlock(&img_req->completion_lock);
rbd_assert(img_req->result <= 0);
if (test_bit(IMG_REQ_CHILD, &img_req->flags)) {
obj_req = img_req->obj_request;
rbd_img_end_child_request(img_req);
result = img_req->result ?: rbd_obj_img_extents_bytes(obj_req);
rbd_img_request_put(img_req);
goto again;
}
rbd_img_end_request(img_req);
Expand Down

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