diff options
| -rw-r--r-- | nbd/server.c | 79 |
1 files changed, 60 insertions, 19 deletions
diff --git a/nbd/server.c b/nbd/server.c index 12f721482d..c3dd402b45 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1844,37 +1844,68 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, return ret; } -static int blockstatus_to_extent_be(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, NBDExtent *extent) +/* + * Populate @extents from block status. Update @bytes to be the actual + * length encoded (which may be smaller than the original), and update + * @nb_extents to the number of extents used. + * + * Returns zero on success and -errno on bdrv_block_status_above failure. + */ +static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, + uint64_t *bytes, NBDExtent *extents, + unsigned int *nb_extents) { - uint64_t remaining_bytes = bytes; + uint64_t remaining_bytes = *bytes; + NBDExtent *extent = extents, *extents_end = extents + *nb_extents; + bool first_extent = true; + assert(*nb_extents); while (remaining_bytes) { uint32_t flags; int64_t num; int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, &num, NULL, NULL); + if (ret < 0) { return ret; } flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); + offset += num; + remaining_bytes -= num; - if (remaining_bytes == bytes) { + if (first_extent) { extent->flags = flags; + extent->length = num; + first_extent = false; + continue; } - if (flags != extent->flags) { - break; + if (flags == extent->flags) { + /* extend current extent */ + extent->length += num; + } else { + if (extent + 1 == extents_end) { + break; + } + + /* start new extent */ + extent++; + extent->flags = flags; + extent->length = num; } + } - offset += num; - remaining_bytes -= num; + extents_end = extent + 1; + + for (extent = extents; extent < extents_end; extent++) { + cpu_to_be32s(&extent->flags); + cpu_to_be32s(&extent->length); } - cpu_to_be32s(&extent->flags); - extent->length = cpu_to_be32(bytes - remaining_bytes); + *bytes -= remaining_bytes; + *nb_extents = extents_end - extents; return 0; } @@ -1910,21 +1941,29 @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle, /* Get block status from the exported device and send it to the client */ static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, BlockDriverState *bs, uint64_t offset, - uint32_t length, bool last, - uint32_t context_id, Error **errp) + uint32_t length, bool dont_fragment, + bool last, uint32_t context_id, + Error **errp) { int ret; - NBDExtent extent; + unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; + NBDExtent *extents = g_new(NBDExtent, nb_extents); + uint64_t final_length = length; - ret = blockstatus_to_extent_be(bs, offset, length, &extent); + ret = blockstatus_to_extents(bs, offset, &final_length, extents, + &nb_extents); if (ret < 0) { + g_free(extents); return nbd_co_send_structured_error( client, handle, -ret, "can't get block status", errp); } - return nbd_co_send_extents(client, handle, &extent, 1, - be32_to_cpu(extent.length), last, - context_id, errp); + ret = nbd_co_send_extents(client, handle, extents, nb_extents, + final_length, last, context_id, errp); + + g_free(extents); + + return ret; } /* @@ -2231,10 +2270,12 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, (client->export_meta.base_allocation || client->export_meta.bitmap)) { + bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; + if (client->export_meta.base_allocation) { ret = nbd_co_send_block_status(client, request->handle, blk_bs(exp->blk), request->from, - request->len, + request->len, dont_fragment, !client->export_meta.bitmap, NBD_META_ID_BASE_ALLOCATION, errp); @@ -2247,7 +2288,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, ret = nbd_co_send_bitmap(client, request->handle, client->exp->export_bitmap, request->from, request->len, - request->flags & NBD_CMD_FLAG_REQ_ONE, + dont_fragment, true, NBD_META_ID_DIRTY_BITMAP, errp); if (ret < 0) { return ret; |