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 2018-01-29 14:04:08 +01:00
parent 45a267dbb4
commit 3da691bf43
1 changed files with 601 additions and 77 deletions

View File

@ -235,11 +235,37 @@ enum obj_req_flags {
OBJ_REQ_EXISTS, /* target exists: no = 0, yes = 1 */ OBJ_REQ_EXISTS, /* target exists: no = 0, yes = 1 */
}; };
/*
* Writes go through the following state machine to deal with
* layering:
*
* need copyup
* RBD_OBJ_WRITE_GUARD ---------------> RBD_OBJ_WRITE_COPYUP
* | ^ |
* v \------------------------------/
* done
* ^
* |
* RBD_OBJ_WRITE_FLAT
*
* Writes start in RBD_OBJ_WRITE_GUARD or _FLAT, depending on whether
* there is a parent or not.
*/
enum rbd_obj_write_state {
RBD_OBJ_WRITE_FLAT = 1,
RBD_OBJ_WRITE_GUARD,
RBD_OBJ_WRITE_COPYUP,
};
struct rbd_obj_request { struct rbd_obj_request {
u64 object_no; u64 object_no;
u64 offset; /* object start byte */ u64 offset; /* object start byte */
u64 length; /* bytes from offset */ u64 length; /* bytes from offset */
unsigned long flags; unsigned long flags;
union {
bool tried_parent; /* for reads */
enum rbd_obj_write_state write_state; /* for writes */
};
/* /*
* An object request associated with an image will have its * An object request associated with an image will have its
@ -1282,6 +1308,27 @@ static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
})); }));
} }
/*
* Zero a range in @obj_req data buffer defined by a bio (list) or
* bio_vec array.
*
* @off is relative to the start of the data buffer.
*/
static void rbd_obj_zero_range(struct rbd_obj_request *obj_req, u32 off,
u32 bytes)
{
switch (obj_req->type) {
case OBJ_REQUEST_BIO:
zero_bios(&obj_req->bio_pos, off, bytes);
break;
case OBJ_REQUEST_BVECS:
zero_bvecs(&obj_req->bvec_pos, off, bytes);
break;
default:
rbd_assert(0);
}
}
/* /*
* The default/initial value for all object request flags is 0. For * The default/initial value for all object request flags is 0. For
* each flag, once its value is set to 1 it is never reset to 0 * each flag, once its value is set to 1 it is never reset to 0
@ -1567,6 +1614,35 @@ rbd_img_request_op_type(struct rbd_img_request *img_request)
return OBJ_OP_READ; return OBJ_OP_READ;
} }
static bool rbd_obj_is_entire(struct rbd_obj_request *obj_req)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
return !obj_req->offset &&
obj_req->length == rbd_dev->layout.object_size;
}
static bool rbd_obj_is_tail(struct rbd_obj_request *obj_req)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
return obj_req->offset + obj_req->length ==
rbd_dev->layout.object_size;
}
static bool rbd_img_is_write(struct rbd_img_request *img_req)
{
switch (rbd_img_request_op_type(img_req)) {
case OBJ_OP_READ:
return false;
case OBJ_OP_WRITE:
case OBJ_OP_DISCARD:
return true;
default:
rbd_assert(0);
}
}
static void static void
rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request) rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
{ {
@ -1697,63 +1773,28 @@ static void rbd_osd_call_callback(struct rbd_obj_request *obj_request)
obj_request_done_set(obj_request); obj_request_done_set(obj_request);
} }
static void rbd_obj_handle_request(struct rbd_obj_request *obj_req);
static void rbd_osd_req_callback(struct ceph_osd_request *osd_req) static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
{ {
struct rbd_obj_request *obj_request = osd_req->r_priv; struct rbd_obj_request *obj_req = osd_req->r_priv;
u16 opcode;
dout("%s: osd_req %p\n", __func__, osd_req); dout("%s osd_req %p result %d for obj_req %p\n", __func__, osd_req,
rbd_assert(osd_req == obj_request->osd_req); osd_req->r_result, obj_req);
if (obj_request_img_data_test(obj_request)) { rbd_assert(osd_req == obj_req->osd_req);
rbd_assert(obj_request->img_request);
rbd_assert(obj_request->which != BAD_WHICH);
} else {
rbd_assert(obj_request->which == BAD_WHICH);
}
if (osd_req->r_result < 0) obj_req->result = osd_req->r_result < 0 ? osd_req->r_result : 0;
obj_request->result = osd_req->r_result; if (!obj_req->result && !rbd_img_is_write(obj_req->img_request))
obj_req->xferred = osd_req->r_result;
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;
/* rbd_obj_handle_request(obj_req);
* We support a 64-bit length, but ultimately it has to be
* passed to the block layer, which just supports a 32-bit
* length field.
*/
obj_request->xferred = osd_req->r_ops[0].outdata_len;
rbd_assert(obj_request->xferred < (u64)UINT_MAX);
opcode = osd_req->r_ops[0].op;
switch (opcode) {
case CEPH_OSD_OP_READ:
rbd_osd_read_callback(obj_request);
break;
case CEPH_OSD_OP_SETALLOCHINT:
rbd_assert(osd_req->r_ops[1].op == CEPH_OSD_OP_WRITE ||
osd_req->r_ops[1].op == CEPH_OSD_OP_WRITEFULL);
/* fall through */
case CEPH_OSD_OP_WRITE:
case CEPH_OSD_OP_WRITEFULL:
rbd_osd_write_callback(obj_request);
break;
case CEPH_OSD_OP_STAT:
rbd_osd_stat_callback(obj_request);
break;
case CEPH_OSD_OP_DELETE:
case CEPH_OSD_OP_TRUNCATE:
case CEPH_OSD_OP_ZERO:
rbd_osd_discard_callback(obj_request);
break;
case CEPH_OSD_OP_CALL:
rbd_osd_call_callback(obj_request);
break;
default:
rbd_warn(NULL, "unexpected OSD op: object_no %016llx opcode %d",
obj_request->object_no, opcode);
break;
}
if (obj_request_done_test(obj_request))
rbd_obj_request_complete(obj_request);
} }
static void rbd_osd_req_format_read(struct rbd_obj_request *obj_request) static void rbd_osd_req_format_read(struct rbd_obj_request *obj_request)
@ -1806,12 +1847,6 @@ __rbd_osd_req_create(struct rbd_device *rbd_dev,
return NULL; return NULL;
} }
/*
* Create an osd request. A read request has one osd op (read).
* A write request has either one (watch) or two (hint+write) osd ops.
* (All rbd data writes are prefixed with an allocation hint op, but
* technically osd watch is a write request, hence this distinction.)
*/
static struct ceph_osd_request *rbd_osd_req_create( static struct ceph_osd_request *rbd_osd_req_create(
struct rbd_device *rbd_dev, struct rbd_device *rbd_dev,
enum obj_operation_type op_type, enum obj_operation_type op_type,
@ -1831,8 +1866,6 @@ static struct ceph_osd_request *rbd_osd_req_create(
snapc = img_request->snapc; snapc = img_request->snapc;
} }
rbd_assert(num_ops == 1 || ((op_type == OBJ_OP_WRITE) && num_ops == 2));
return __rbd_osd_req_create(rbd_dev, snapc, num_ops, return __rbd_osd_req_create(rbd_dev, snapc, num_ops,
(op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD) ? (op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD) ?
CEPH_OSD_FLAG_WRITE : CEPH_OSD_FLAG_READ, obj_request); CEPH_OSD_FLAG_WRITE : CEPH_OSD_FLAG_READ, obj_request);
@ -2251,6 +2284,211 @@ static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
rbd_osd_req_format_read(obj_request); rbd_osd_req_format_read(obj_request);
} }
static void rbd_osd_req_setup_data(struct rbd_obj_request *obj_req, u32 which)
{
switch (obj_req->type) {
case OBJ_REQUEST_BIO:
osd_req_op_extent_osd_data_bio(obj_req->osd_req, which,
&obj_req->bio_pos,
obj_req->length);
break;
case OBJ_REQUEST_BVECS:
rbd_assert(obj_req->bvec_pos.iter.bi_size ==
obj_req->length);
osd_req_op_extent_osd_data_bvec_pos(obj_req->osd_req, which,
&obj_req->bvec_pos);
break;
default:
rbd_assert(0);
}
}
static int rbd_obj_setup_read(struct rbd_obj_request *obj_req)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
obj_req->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1, obj_req);
if (!obj_req->osd_req)
return -ENOMEM;
osd_req_op_extent_init(obj_req->osd_req, 0, CEPH_OSD_OP_READ,
obj_req->offset, obj_req->length, 0, 0);
rbd_osd_req_setup_data(obj_req, 0);
rbd_osd_req_format_read(obj_req);
return 0;
}
static int __rbd_obj_setup_stat(struct rbd_obj_request *obj_req,
unsigned int which)
{
struct page **pages;
/*
* The response data for a STAT call consists of:
* le64 length;
* struct {
* le32 tv_sec;
* le32 tv_nsec;
* } mtime;
*/
pages = ceph_alloc_page_vector(1, GFP_NOIO);
if (IS_ERR(pages))
return PTR_ERR(pages);
osd_req_op_init(obj_req->osd_req, which, CEPH_OSD_OP_STAT, 0);
osd_req_op_raw_data_in_pages(obj_req->osd_req, which, pages,
8 + sizeof(struct ceph_timespec),
0, false, true);
return 0;
}
static void __rbd_obj_setup_write(struct rbd_obj_request *obj_req,
unsigned int which)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
u16 opcode;
osd_req_op_alloc_hint_init(obj_req->osd_req, which++,
rbd_dev->layout.object_size,
rbd_dev->layout.object_size);
if (rbd_obj_is_entire(obj_req))
opcode = CEPH_OSD_OP_WRITEFULL;
else
opcode = CEPH_OSD_OP_WRITE;
osd_req_op_extent_init(obj_req->osd_req, which, opcode,
obj_req->offset, obj_req->length, 0, 0);
rbd_osd_req_setup_data(obj_req, which++);
rbd_assert(which == obj_req->osd_req->r_num_ops);
rbd_osd_req_format_write(obj_req);
}
static int rbd_obj_setup_write(struct rbd_obj_request *obj_req)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
unsigned int num_osd_ops, which = 0;
int ret;
if (obj_request_overlaps_parent(obj_req)) {
obj_req->write_state = RBD_OBJ_WRITE_GUARD;
num_osd_ops = 3; /* stat + setallochint + write/writefull */
} else {
obj_req->write_state = RBD_OBJ_WRITE_FLAT;
num_osd_ops = 2; /* setallochint + write/writefull */
}
obj_req->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_WRITE,
num_osd_ops, obj_req);
if (!obj_req->osd_req)
return -ENOMEM;
if (obj_request_overlaps_parent(obj_req)) {
ret = __rbd_obj_setup_stat(obj_req, which++);
if (ret)
return ret;
}
__rbd_obj_setup_write(obj_req, which);
return 0;
}
static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,
unsigned int which)
{
u16 opcode;
if (rbd_obj_is_entire(obj_req)) {
if (obj_request_overlaps_parent(obj_req)) {
opcode = CEPH_OSD_OP_TRUNCATE;
} else {
osd_req_op_init(obj_req->osd_req, which++,
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;
}
if (opcode)
osd_req_op_extent_init(obj_req->osd_req, which++, opcode,
obj_req->offset, obj_req->length,
0, 0);
rbd_assert(which == obj_req->osd_req->r_num_ops);
rbd_osd_req_format_write(obj_req);
}
static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
{
struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
unsigned int num_osd_ops, which = 0;
int ret;
if (rbd_obj_is_entire(obj_req)) {
obj_req->write_state = RBD_OBJ_WRITE_FLAT;
num_osd_ops = 1; /* truncate/delete */
} else {
if (obj_request_overlaps_parent(obj_req)) {
obj_req->write_state = RBD_OBJ_WRITE_GUARD;
num_osd_ops = 2; /* stat + truncate/zero */
} else {
obj_req->write_state = RBD_OBJ_WRITE_FLAT;
num_osd_ops = 1; /* truncate/zero */
}
}
obj_req->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_DISCARD,
num_osd_ops, obj_req);
if (!obj_req->osd_req)
return -ENOMEM;
if (!rbd_obj_is_entire(obj_req) &&
obj_request_overlaps_parent(obj_req)) {
ret = __rbd_obj_setup_stat(obj_req, which++);
if (ret)
return ret;
}
__rbd_obj_setup_discard(obj_req, which);
return 0;
}
/*
* For each object request in @img_req, allocate an OSD request, add
* individual OSD ops and prepare them for submission. The number of
* OSD ops depends on op_type and the overlap point (if any).
*/
static int __rbd_img_fill_request(struct rbd_img_request *img_req)
{
struct rbd_obj_request *obj_req;
int ret;
for_each_obj_request(img_req, obj_req) {
switch (rbd_img_request_op_type(img_req)) {
case OBJ_OP_READ:
ret = rbd_obj_setup_read(obj_req);
break;
case OBJ_OP_WRITE:
ret = rbd_obj_setup_write(obj_req);
break;
case OBJ_OP_DISCARD:
ret = rbd_obj_setup_discard(obj_req);
break;
default:
rbd_assert(0);
}
if (ret)
return ret;
}
return 0;
}
/* /*
* Split up an image request into one or more object requests, each * Split up an image request into one or more object requests, each
* to a different object. The "type" parameter indicates whether * to a different object. The "type" parameter indicates whether
@ -2268,7 +2506,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
struct rbd_obj_request *next_obj_request; struct rbd_obj_request *next_obj_request;
struct ceph_bio_iter bio_it; struct ceph_bio_iter bio_it;
struct ceph_bvec_iter bvec_it; struct ceph_bvec_iter bvec_it;
enum obj_operation_type op_type;
u64 img_offset; u64 img_offset;
u64 resid; u64 resid;
@ -2278,7 +2515,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
img_offset = img_request->offset; img_offset = img_request->offset;
resid = img_request->length; resid = img_request->length;
rbd_assert(resid > 0); rbd_assert(resid > 0);
op_type = rbd_img_request_op_type(img_request);
if (type == OBJ_REQUEST_BIO) { if (type == OBJ_REQUEST_BIO) {
bio_it = *(struct ceph_bio_iter *)data_desc; 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) { while (resid) {
struct ceph_osd_request *osd_req;
u64 object_no = img_offset >> rbd_dev->header.obj_order; u64 object_no = img_offset >> rbd_dev->header.obj_order;
u64 offset = rbd_segment_offset(rbd_dev, img_offset); u64 offset = rbd_segment_offset(rbd_dev, img_offset);
u64 length = rbd_segment_length(rbd_dev, img_offset, resid); 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); 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->callback = rbd_img_obj_callback;
obj_request->img_offset = img_offset; obj_request->img_offset = img_offset;
rbd_img_obj_request_fill(obj_request, osd_req, op_type, 0);
img_offset += length; img_offset += length;
resid -= length; resid -= length;
} }
return 0; return __rbd_img_fill_request(img_request);
out_unwind: out_unwind:
for_each_obj_request_safe(img_request, obj_request, next_obj_request) 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); rbd_img_request_get(img_request);
for_each_obj_request_safe(img_request, obj_request, next_obj_request) { for_each_obj_request_safe(img_request, obj_request, next_obj_request) {
ret = rbd_img_obj_request_submit(obj_request); rbd_obj_request_submit(obj_request);
if (ret)
goto out_put_ireq;
} }
out_put_ireq:
rbd_img_request_put(img_request); rbd_img_request_put(img_request);
return ret; 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) static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
{ {
u32 i; u32 i;
@ -2850,6 +3231,149 @@ static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
obj_request_done_set(obj_request); 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 const struct rbd_client_id rbd_empty_cid;
static bool rbd_cid_equal(const struct rbd_client_id *lhs, static bool rbd_cid_equal(const struct rbd_client_id *lhs,