volumes::edit

Tag 9: a client names a volume from its listing and states its size in bytes; the server sends exactly one response stating that the volume has that size, that the server has insufficient capacity for it, that the content of the volume exceeds it, or an error, and the scope finishes; the size is the only property an edit changes.

A client opens the scope with a request whose payload is the tag byte 9 followed by the name of a volume and a size. The server sends exactly one response, which states that the volume has the size stated, that the server has insufficient capacity for it, that the content of the volume exceeds it, or an error. The response finish follows the response, and no frame follows the finish.

The request. The request carries the name of one volume and a size in bytes. Request states its form.
The volume named. The client names a volume by the name its volumes::list listing gave it. The server resolves the name against the identity under which the connection was authorized, as Authorization provides. A name that is not in the client’s listing is answered with an error. A client cannot name another client’s volume. A server may refuse to edit a volume that it offered on its own account and that the client did not create; the refusal is an error.
The size. The size is absolute: the request states the size the volume has after the edit, not a change to its size. When the server sends the byte 0, the volume has the size stated. From that moment, every volumes::list listing and every volumes::stat response of the client reports that size as bytes, until a later edit changes it. The size is the only property an edit changes: the name, the content, the bytes in use and the hash of the content are as they were before the request. Response states the form of the response.
Insufficient capacity. When the server cannot reserve the size stated, it does not change the size and sends the byte 1. The volume has the size it had before the request. The server does not send the byte 0 for a size it cannot reserve. The number of bytes by which the volume can grow at a given time is reported by volumes::edit_capacity.
Content too large. When the size stated is smaller than the number of bytes the volume holds, the server does not change the size and sends the byte 2. The volume has the size it had before the request, and its content is as it was. The server does not send the byte 0 for a size that the content of the volume exceeds. A client that wants the smaller size removes content from the volume, by a container in which the volume is mounted, and asks again.
The error. An error states that the size was not changed, for a reason other than capacity or content: the volume has the size it had before the request, and every listing and every stat reports that size.

In this section

Request — The payload is the tag byte 9 followed by the name of the volume as a varint length and UTF-8 bytes and its size in bytes as a varint, in the postcard wire format.
Response — The server sends exactly one response, whose payload is exactly the byte 0 when the volume has the size stated, exactly the byte 1 when the server has insufficient capacity for it, exactly the byte 2 when the content of the volume exceeds it, or the byte 3 followed by an error as one JSON value, and the response finish follows it.