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sheepdog: resend write requests when SD_RES_READONLY is received

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When a snapshot is taken from out side of qemu (e.g. qemu-img
snapshot), write requests to the current vdi return SD_RES_READONLY.
In this case, the sheepdog block driver needs to update the current
inode to the latest one and resend the write requests.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
MORITA Kazutaka 2013-04-26 01:19:54 +09:00 committed by Stefan Hajnoczi
parent 9ff53a0eb8
commit 13c31de2fd
1 changed files with 59 additions and 1 deletions
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60
block/sheepdog.c
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@ -605,6 +605,7 @@ static int do_req(int sockfd, SheepdogReq *hdr, void *data,
static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
struct iovec *iov, int niov, bool create,
enum AIOCBState aiocb_type);
static int coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req);
static AIOReq *find_pending_req(BDRVSheepdogState *s, uint64_t oid)
@ -749,9 +750,19 @@ static void coroutine_fn aio_read_response(void *opaque)
}
}
if (rsp.result != SD_RES_SUCCESS) {
switch (rsp.result) {
case SD_RES_SUCCESS:
break;
case SD_RES_READONLY:
ret = resend_aioreq(s, aio_req);
if (ret == SD_RES_SUCCESS) {
goto out;
}
/* fall through */
default:
acb->ret = -EIO;
error_report("%s", sd_strerror(rsp.result));
break;
}
free_aio_req(s, aio_req);
@ -1186,6 +1197,53 @@ out:
return ret;
}
static int coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
{
SheepdogAIOCB *acb = aio_req->aiocb;
bool create = false;
int ret;
ret = reload_inode(s, 0, "");
if (ret < 0) {
return ret;
}
aio_req->oid = vid_to_data_oid(s->inode.vdi_id,
data_oid_to_idx(aio_req->oid));
/* check whether this request becomes a CoW one */
if (acb->aiocb_type == AIOCB_WRITE_UDATA) {
int idx = data_oid_to_idx(aio_req->oid);
AIOReq *areq;
if (s->inode.data_vdi_id[idx] == 0) {
create = true;
goto out;
}
if (is_data_obj_writable(&s->inode, idx)) {
goto out;
}
/* link to the pending list if there is another CoW request to
* the same object */
QLIST_FOREACH(areq, &s->inflight_aio_head, aio_siblings) {
if (areq != aio_req && areq->oid == aio_req->oid) {
dprintf("simultaneous CoW to %" PRIx64 "\n", aio_req->oid);
QLIST_REMOVE(aio_req, aio_siblings);
QLIST_INSERT_HEAD(&s->pending_aio_head, aio_req, aio_siblings);
return SD_RES_SUCCESS;
}
}
aio_req->base_oid = vid_to_data_oid(s->inode.data_vdi_id[idx], idx);
aio_req->flags |= SD_FLAG_CMD_COW;
create = true;
}
out:
return add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
create, acb->aiocb_type);
}
/* TODO Convert to fine grained options */
static QemuOptsList runtime_opts = {
.name = "sheepdog",