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sheepdog: reorganize coroutine flow 

Delimit co_recv's lifetime clearly in aio_read_response.

Do a simple qemu_coroutine_enter in aio_read_response, letting
sd_co_writev call sd_write_done.

Handle nr_pending in the same way in sd_co_rw_vector,
sd_write_done and sd_co_flush_to_disk.

Remove sd_co_rw_vector's return value; just leave with no
pending requests.

[Jeff: added missing 'return' back, spotted by Paolo after
       series was applied.]

Signed-off-by: Jeff Cody <jcody@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-11-29 12:32:42 +01:00 committed by Jeff Cody
parent a71264f9f5
commit e80ab33dc0
1 changed files with 42 additions and 73 deletions
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115
block/sheepdog.c
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@ -345,8 +345,6 @@ struct SheepdogAIOCB {
enum AIOCBState aiocb_type;
Coroutine *coroutine;
void (*aio_done_func)(SheepdogAIOCB *);
int nr_pending;
uint32_t min_affect_data_idx;
@ -449,14 +447,13 @@ static const char * sd_strerror(int err)
*
* 1. In sd_co_rw_vector, we send the I/O requests to the server and
* link the requests to the inflight_list in the
* BDRVSheepdogState. The function exits without waiting for
* BDRVSheepdogState. The function yields while waiting for
* receiving the response.
*
* 2. We receive the response in aio_read_response, the fd handler to
* the sheepdog connection. If metadata update is needed, we send
* the write request to the vdi object in sd_write_done, the write
* completion function. We switch back to sd_co_readv/writev after
* all the requests belonging to the AIOCB are finished.
* the sheepdog connection. We switch back to sd_co_readv/sd_writev
* after all the requests belonging to the AIOCB are finished. If
* needed, sd_co_writev will send another requests for the vdi object.
*/
static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
@ -491,12 +488,6 @@ static inline void free_aio_req(BDRVSheepdogState *s, AIOReq *aio_req)
acb->nr_pending--;
}
static void coroutine_fn sd_finish_aiocb(SheepdogAIOCB *acb)
{
qemu_coroutine_enter(acb->coroutine);
qemu_aio_unref(acb);
}
static const AIOCBInfo sd_aiocb_info = {
.aiocb_size = sizeof(SheepdogAIOCB),
};
@ -517,7 +508,6 @@ static SheepdogAIOCB *sd_aio_setup(BlockDriverState *bs, QEMUIOVector *qiov,
acb->sector_num = sector_num;
acb->nb_sectors = nb_sectors;
acb->aio_done_func = NULL;
acb->coroutine = qemu_coroutine_self();
acb->ret = 0;
acb->nr_pending = 0;
@ -788,9 +778,6 @@ static void coroutine_fn aio_read_response(void *opaque)
switch (acb->aiocb_type) {
case AIOCB_WRITE_UDATA:
/* this coroutine context is no longer suitable for co_recv
* because we may send data to update vdi objects */
s->co_recv = NULL;
if (!is_data_obj(aio_req->oid)) {
break;
}
@ -838,6 +825,11 @@ static void coroutine_fn aio_read_response(void *opaque)
}
}
/* No more data for this aio_req (reload_inode below uses its own file
* descriptor handler which doesn't use co_recv).
*/
s->co_recv = NULL;
switch (rsp.result) {
case SD_RES_SUCCESS:
break;
@ -855,7 +847,7 @@ static void coroutine_fn aio_read_response(void *opaque)
aio_req->oid = vid_to_vdi_oid(s->inode.vdi_id);
}
resend_aioreq(s, aio_req);
goto out;
return;
default:
acb->ret = -EIO;
error_report("%s", sd_strerror(rsp.result));
@ -868,13 +860,12 @@ static void coroutine_fn aio_read_response(void *opaque)
* We've finished all requests which belong to the AIOCB, so
* we can switch back to sd_co_readv/writev now.
*/
acb->aio_done_func(acb);
qemu_coroutine_enter(acb->coroutine);
}
out:
s->co_recv = NULL;
return;
err:
s->co_recv = NULL;
reconnect_to_sdog(opaque);
}
@ -1973,7 +1964,6 @@ static int sd_truncate(BlockDriverState *bs, int64_t offset)
/*
* This function is called after writing data objects. If we need to
* update metadata, this sends a write request to the vdi object.
* Otherwise, this switches back to sd_co_readv/writev.
*/
static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
{
@ -1986,6 +1976,7 @@ static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
mx = acb->max_dirty_data_idx;
if (mn <= mx) {
/* we need to update the vdi object. */
++acb->nr_pending;
offset = sizeof(s->inode) - sizeof(s->inode.data_vdi_id) +
mn * sizeof(s->inode.data_vdi_id[0]);
data_len = (mx - mn + 1) * sizeof(s->inode.data_vdi_id[0]);
@ -1999,13 +1990,10 @@ static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
data_len, offset, 0, false, 0, offset);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
acb->aio_done_func = sd_finish_aiocb;
acb->aiocb_type = AIOCB_WRITE_UDATA;
return;
if (--acb->nr_pending) {
qemu_coroutine_yield();
}
}
sd_finish_aiocb(acb);
}
/* Delete current working VDI on the snapshot chain */
@ -2117,7 +2105,7 @@ out:
* Returns 1 when we need to wait a response, 0 when there is no sent
* request and -errno in error cases.
*/
static int coroutine_fn sd_co_rw_vector(void *p)
static void coroutine_fn sd_co_rw_vector(void *p)
{
SheepdogAIOCB *acb = p;
int ret = 0;
@ -2138,7 +2126,7 @@ static int coroutine_fn sd_co_rw_vector(void *p)
ret = sd_create_branch(s);
if (ret) {
acb->ret = -EIO;
goto out;
return;
}
}
@ -2212,11 +2200,9 @@ static int coroutine_fn sd_co_rw_vector(void *p)
idx++;
done += len;
}
out:
if (!--acb->nr_pending) {
return acb->ret;
if (--acb->nr_pending) {
qemu_coroutine_yield();
}
return 1;
}
static bool check_overlapping_aiocb(BDRVSheepdogState *s, SheepdogAIOCB *aiocb)
@ -2249,7 +2235,6 @@ static coroutine_fn int sd_co_writev(BlockDriverState *bs, int64_t sector_num,
}
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors);
acb->aio_done_func = sd_write_done;
acb->aiocb_type = AIOCB_WRITE_UDATA;
retry:
@ -2258,20 +2243,14 @@ retry:
goto retry;
}
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
QLIST_REMOVE(acb, aiocb_siblings);
qemu_co_queue_restart_all(&s->overlapping_queue);
qemu_aio_unref(acb);
return ret;
}
qemu_coroutine_yield();
sd_co_rw_vector(acb);
sd_write_done(acb);
QLIST_REMOVE(acb, aiocb_siblings);
qemu_co_queue_restart_all(&s->overlapping_queue);
return acb->ret;
ret = acb->ret;
qemu_aio_unref(acb);
return ret;
}
static coroutine_fn int sd_co_readv(BlockDriverState *bs, int64_t sector_num,
@ -2283,7 +2262,6 @@ static coroutine_fn int sd_co_readv(BlockDriverState *bs, int64_t sector_num,
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors);
acb->aiocb_type = AIOCB_READ_UDATA;
acb->aio_done_func = sd_finish_aiocb;
retry:
if (check_overlapping_aiocb(s, acb)) {
@ -2291,25 +2269,20 @@ retry:
goto retry;
}
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
QLIST_REMOVE(acb, aiocb_siblings);
qemu_co_queue_restart_all(&s->overlapping_queue);
qemu_aio_unref(acb);
return ret;
}
qemu_coroutine_yield();
sd_co_rw_vector(acb);
QLIST_REMOVE(acb, aiocb_siblings);
qemu_co_queue_restart_all(&s->overlapping_queue);
return acb->ret;
ret = acb->ret;
qemu_aio_unref(acb);
return ret;
}
static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
{
BDRVSheepdogState *s = bs->opaque;
SheepdogAIOCB *acb;
int ret;
AIOReq *aio_req;
if (s->cache_flags != SD_FLAG_CMD_CACHE) {
@ -2318,15 +2291,19 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
acb = sd_aio_setup(bs, NULL, 0, 0);
acb->aiocb_type = AIOCB_FLUSH_CACHE;
acb->aio_done_func = sd_finish_aiocb;
acb->nr_pending++;
aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
0, 0, 0, false, 0, 0);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
add_aio_request(s, aio_req, NULL, 0, acb->aiocb_type);
qemu_coroutine_yield();
return acb->ret;
if (--acb->nr_pending) {
qemu_coroutine_yield();
}
ret = acb->ret;
qemu_aio_unref(acb);
return ret;
}
static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
@ -2783,7 +2760,6 @@ static coroutine_fn int sd_co_pdiscard(BlockDriverState *bs, int64_t offset,
acb = sd_aio_setup(bs, &discard_iov, offset >> BDRV_SECTOR_BITS,
count >> BDRV_SECTOR_BITS);
acb->aiocb_type = AIOCB_DISCARD_OBJ;
acb->aio_done_func = sd_finish_aiocb;
retry:
if (check_overlapping_aiocb(s, acb)) {
@ -2791,20 +2767,13 @@ retry:
goto retry;
}
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
QLIST_REMOVE(acb, aiocb_siblings);
qemu_co_queue_restart_all(&s->overlapping_queue);
qemu_aio_unref(acb);
return ret;
}
qemu_coroutine_yield();
sd_co_rw_vector(acb);
QLIST_REMOVE(acb, aiocb_siblings);
qemu_co_queue_restart_all(&s->overlapping_queue);
return acb->ret;
ret = acb->ret;
qemu_aio_unref(acb);
return ret;
}
static coroutine_fn int64_t