[Libguestfs] [libnbd PATCH 0/3] Expose server block size constraints

Necessary when writing a client that wants to avoid unnecessary EINVAL errors from sending unaligned requests. At some point, we may want to add synchronous convenience API wrappers that do request splitting or read-modify-write to obey server constraints while still appearing to the library client as accepting any possible request. But such a wrapper should only be synchronous and not copied to nbd_aio_*, because getting locking right is a bear if you have two non-overlapping client requests that want to visit the same larger-granularity window of the server in parallel. Eric Blake (3): states: Request NBD_INFO_BLOCK_SIZE during NBD_OPT_GO api: Add new API to query negotiated block size nbdinfo: Expose block size constraints info/nbdinfo.pod | 6 +++ lib/internal.h | 7 +++ lib/nbd-protocol.h | 10 ++++- generator/API.ml | 70 +++++++++++++++++++++++++++--- generator/state_machine.ml | 7 +++ generator/states-newstyle-opt-go.c | 31 +++++++++++-- lib/flags.c | 18 +++++++- info/nbdinfo.c | 18 ++++++++ 8 files changed, 156 insertions(+), 11 deletions(-) -- 2.27.0