[sheepdog] [PATCH v2] sheep: handle a case of small buffer in cinfo collection
Hitoshi Mitake
mitake.hitoshi at lab.ntt.co.jp
Mon Dec 15 05:54:02 CET 2014
At Thu, 11 Dec 2014 11:15:27 +0900,
Hitoshi Mitake wrote:
>
> Current cinfo_collection_work() and SD_OP_VDI_STATE_SNAPSHOT_CTL
> doesn't handle a case of small buffer. This patch solves it.
>
> Cc: Saeki Masaki <saeki.masaki at po.ntts.co.jp>
> Cc: Yuka Kawasaki <kawasaki.yuka at po.ntts.co.jp>
> Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
> ---
> sheep/group.c | 56 +++++++++++++++++++++++++++++++++++++++---------------
> sheep/ops.c | 21 ++++++++++----------
> sheep/sheep_priv.h | 3 ++-
> sheep/vdi.c | 24 ++++++++++++++++-------
> 4 files changed, 71 insertions(+), 33 deletions(-)
>
> v2: calculate correct length of buffer
Sorry, this version also has a bug. I'll post v3 later.
Thanks,
Hitoshi
>
> diff --git a/sheep/group.c b/sheep/group.c
> index 2b98a9b..e633bc3 100644
> --- a/sheep/group.c
> +++ b/sheep/group.c
> @@ -694,43 +694,69 @@ struct cinfo_collection_work {
>
> static struct cinfo_collection_work *collect_work;
>
> -static void cinfo_collection_work(struct work *work)
> +static struct vdi_state *do_cinfo_collection_work(uint32_t epoch,
> + struct sd_node *n,
> + int *nr_vdi_states)
> {
> + struct vdi_state *vs = NULL;
> + unsigned int rlen = 512;
> struct sd_req hdr;
> struct sd_rsp *rsp = (struct sd_rsp *)&hdr;
> + int ret;
> +
> + vs = xcalloc(rlen, sizeof(*vs));
> +
> +retry:
> + sd_init_req(&hdr, SD_OP_VDI_STATE_SNAPSHOT_CTL);
> + hdr.vdi_state_snapshot.get = 1;
> + hdr.vdi_state_snapshot.tgt_epoch = epoch;
> + hdr.data_length = rlen;
> +
> + ret = sheep_exec_req(&n->nid, &hdr, (char *)vs);
> + if (ret == SD_RES_SUCCESS) {
> + sd_debug("succeed to obtain snapshot of vdi states");
> + *nr_vdi_states = rsp->data_length / sizeof(*vs);
> + return vs;
> + } else if (ret == SD_RES_BUFFER_SMALL) {
> + sd_debug("buffer is small for obtaining snapshot of vdi states,"
> + " doubling it (%lu -> %lu)", rlen * sizeof(*vs),
> + rlen * 2 * sizeof(*vs));
> + rlen *= 2;
> + vs = xrealloc(vs, sizeof(*vs) * rlen);
> + goto retry;
> + }
> +
> + sd_err("failed to obtain snapshot of vdi states from node %s",
> + node_to_str(n));
> + return NULL;
> +}
> +
> +static void cinfo_collection_work(struct work *work)
> +{
> + struct sd_req hdr;
> struct vdi_state *vs = NULL;
> - unsigned int rlen;
> struct cinfo_collection_work *w =
> container_of(work, struct cinfo_collection_work, work);
> struct sd_node *n;
> - int ret;
> + int ret, nr_vdi_states = 0;
>
> sd_debug("start collection of cinfo...");
>
> assert(w == collect_work);
>
> - rlen = SD_DATA_OBJ_SIZE; /* FIXME */
> - vs = xzalloc(rlen);
> -
> rb_for_each_entry(n, &w->members->nroot, rb) {
> if (node_is_local(n))
> continue;
>
> - sd_init_req(&hdr, SD_OP_VDI_STATE_SNAPSHOT_CTL);
> - hdr.vdi_state_snapshot.get = 1;
> - hdr.vdi_state_snapshot.tgt_epoch = w->epoch;
> - hdr.data_length = rlen;
> -
> - ret = sheep_exec_req(&n->nid, &hdr, (char *)vs);
> - if (ret == SD_RES_SUCCESS)
> + vs = do_cinfo_collection_work(w->epoch, n, &nr_vdi_states);
> + if (vs)
> goto get_succeed;
> }
>
> panic("getting a snapshot of vdi state at epoch %d failed", w->epoch);
>
> get_succeed:
> -
> - w->nr_vdi_states = rsp->data_length / sizeof(*vs);
> + w->nr_vdi_states = nr_vdi_states;
> w->result = vs;
>
> sd_debug("collecting cinfo done, freeing from remote nodes");
> diff --git a/sheep/ops.c b/sheep/ops.c
> index a617a83..3991060 100644
> --- a/sheep/ops.c
> +++ b/sheep/ops.c
> @@ -1391,21 +1391,22 @@ static int local_vdi_state_snapshot_ctl(const struct sd_req *req,
> {
> bool get = !!req->vdi_state_snapshot.get;
> int epoch = req->vdi_state_snapshot.tgt_epoch;
> - int ret;
> + int ret, length = 0;
>
> sd_info("%s vdi state snapshot at epoch %d",
> get ? "getting" : "freeing", epoch);
>
> if (get) {
> - /*
> - * FIXME: assuming request has enough space for storing
> - * the snapshot
> - */
> - ret = get_vdi_state_snapshot(epoch, data);
> - if (0 <= ret)
> - rsp->data_length = ret;
> - else
> - return SD_RES_AGAIN;
> + ret = get_vdi_state_snapshot(epoch, data, req->data_length,
> + &length);
> + if (ret == SD_RES_SUCCESS)
> + rsp->data_length = length;
> + else {
> + sd_err("failed to get vdi state snapshot: %s",
> + sd_strerror(ret));
> +
> + return ret;
> + }
> } else
> free_vdi_state_snapshot(epoch);
>
> diff --git a/sheep/sheep_priv.h b/sheep/sheep_priv.h
> index 5fc6b90..72817b9 100644
> --- a/sheep/sheep_priv.h
> +++ b/sheep/sheep_priv.h
> @@ -344,7 +344,8 @@ bool vdi_lock(uint32_t vid, const struct node_id *owner, int type);
> bool vdi_unlock(uint32_t vid, const struct node_id *owner, int type);
> void apply_vdi_lock_state(struct vdi_state *vs);
> void take_vdi_state_snapshot(int epoch);
> -int get_vdi_state_snapshot(int epoch, void *data);
> +int get_vdi_state_snapshot(int epoch, void *data, int data_len_max,
> + int *data_len_result);
> void free_vdi_state_snapshot(int epoch);
> void log_vdi_op_lock(uint32_t vid, const struct node_id *owner, int type);
> void log_vdi_op_unlock(uint32_t vid, const struct node_id *owner, int type);
> diff --git a/sheep/vdi.c b/sheep/vdi.c
> index 1c8fb36..a85bbf5 100644
> --- a/sheep/vdi.c
> +++ b/sheep/vdi.c
> @@ -1793,21 +1793,31 @@ main_fn void take_vdi_state_snapshot(int epoch)
> sd_debug("a number of vdi state: %d", snapshot->nr_vs);
> }
>
> -main_fn int get_vdi_state_snapshot(int epoch, void *data)
> +main_fn int get_vdi_state_snapshot(int epoch, void *data, int data_len_max,
> + int *data_len_result)
> {
> struct vdi_state_snapshot *snapshot;
> + int len;
>
> list_for_each_entry(snapshot, &vdi_state_snapshot_list, list) {
> - if (snapshot->epoch == epoch) {
> - memcpy(data, snapshot->vs,
> - sizeof(*snapshot->vs) * snapshot->nr_vs);
> - return sizeof(*snapshot->vs) * snapshot->nr_vs;
> - }
> + if (snapshot->epoch == epoch)
> + goto found;
> }
>
> sd_info("get request for not prepared vdi state snapshot, epoch: %d",
> epoch);
> - return -1;
> + return SD_RES_AGAIN;
> +
> +found:
> + len = sizeof(*snapshot->vs) * snapshot->nr_vs;
> + if (data_len_max < len) {
> + sd_info("maximum allowed length: %d, required length: %d",
> + data_len_max, len);
> + return SD_RES_BUFFER_SMALL;
> + }
> +
> + memcpy(data, snapshot->vs, len);
> + return len;
> }
>
> main_fn void free_vdi_state_snapshot(int epoch)
> --
> 1.8.3.2
>
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