Security

There were no security issues found. All past security issues and information about how to report new ones can be found in nbdkit-security(1).

Plugins

nbdkit-streaming-plugin has been removed. It was deprecated in 1.26 and scheduled for removal in this release. If you were using this plugin, use nbdcopy(1) instead.

nbdkit-vddk-plugin(1) has several changes:

• This plugin can now create (as well as reading and writing) local VMDK files. See the new "create=true" option and the various "create-*" options.
• Read and write is now implemented using the VDDK Async functions, which improves performance. The full nbdkit parallel thread model is supported.
• VDDK ≥ 6.5 (released Nov 2016) is now the minimum required version.
• Stats collected when using -D vddk.stats=1 have been extended to include number of calls and bytes transferred.
• --dump-plugin output now includes the VDDK major version and information about each VDDK API that is implemented by the library.
• A new example scripts/vddk-open.sh is provided to help with automating connections to remote ESXi virtual machines.

nbdkit-curl-plugin(1) adds support for choosing TLS/SSL versions and ciphers and TLS 1.3 cipher versions (Przemyslaw Czarnowski).

nbdkit-file-plugin(1) now implements "cache=none" for writes so that the Linux page cache is not destroyed when writing huge files.

nbdkit-cc-plugin(1) now implements the ".cleanup" callback. Also we document how to use this plugin to implement OCaml plugin scripts.

nbdkit-info-plugin(1) --dump-plugin option now prints "info_address=yes" when the platform supports "mode=address".

Filters

New nbdkit-retry-request-filter(1), which is similar to nbdkit-retry-filter(1) but only retries a single failing request.

New nbdkit-protect-filter(1) lets you add write-protection over regions of a plugin.

New nbdkit-blocksize-policy-filter(1) lets you adjust or set the block size constraints and policy of underlying plugins. See "API" below.

nbdkit-cow-filter(1) now permits the COW block size to be set as small as 4096 bytes.

Debug messages in nbdkit-error-filter(1) are now easier to read because they no longer all have an "error:" prefix (Eric Blake).

Language bindings

For plugins written in OCaml the minimum version of OCaml is now 4.03 (instead of 4.02.2 previously). Various source-level incompatible changes were made to OCaml plugins in this release. Please consult the new documentation and example if writing plugins in OCaml.

OCaml plugins now support "magic_config_key".

Several fixes to the handling of integers in Python plugins (Nir Soffer).

New Python example which simulates request errors (Nir Soffer).

Server

The server no longer requests the "AI_ADDRCONFIG" hint when opening a server socket. This improves handling of IPv6. In a related change, the -i (--ipaddr) option now works as intended, and new -4 and -6 options have been added to restrict the listening socket to IPv4 or IPv6 addresses (Laszlo Ersek).

API

There is a new ".block_size" callback for plugins and filters. nbdkit uses this to export block size constraints to clients, specifically the minimum, preferred and maximum block size that clients should use.

As well as regular C plugins, nbdkit-cc-plugin(3), nbdkit-eval-plugin(1), nbdkit-ocaml-plugin(3), nbdkit-python-plugin(3) and nbdkit-sh-plugin(3) support block size constraints. nbdkit-nbd-plugin(1) reexports block size constraints from the proxied NBD server. nbdkit-vddk-plugin(1) now advertises a minimum 512 byte block size.

nbdkit-blocksize-filter(1), nbdkit-cache-filter(1), nbdkit-cow-filter(1) and nbdkit-swab-filter(1) adjust block size constraints from plugins (Eric Blake).

nbdkit-blocksize-filter(1) can also use the block size hints from the plugin instead of needing manual adjustment on the command line. nbdkit-log-filter(1) logs block size constraints (Eric Blake).

nbdkit-blocksize-policy-filter(1) can be used to add block size constraints to plugins which don't support it, or adjust constraints, or set the error policy.

Bug fixes

nbdkit-memory-plugin(1) (and others), using "allocator=malloc,mlock=true" was broken. This was especially evident on non-Linux or on Linux with 64K pages (eg. POWER). It should now work correctly.

Tests

"./configure --disable-libguestfs-tests" can now be used to disable tests which need libguestfs, without disabling nbdkit-guestfs-plugin(1).

We now use mke2fs(8) instead of guestfish(1) to create the ext4 test image. On armv7 this allows the test suite to run much more quickly.

The time taken to run the test suite has been reduced significantly.

Build

Multiple fixes to the Windows (MinGW) build. The test suite should now pass fully if you have the version of Wine with the unofficial "AF_UNIX" patch.

The top level bash source directory has been renamed to bash-completion. This prevents problems when setting $PATH to the source directory and trying to run bash.

Internals

The performance of the internal vector library has been improved greatly and overflow is now handled correctly (Nir Soffer, Laszlo Ersek and Eric Blake).

New "nbdkit-string.h" header file which defines a common string type (based on vector). Existing places which defined a string based on vector have been updated to use it.

"MIN" and "MAX" macros can be nested (thanks Eric Blake).