Released on 2020-04-20.
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The reconfiguration protocol has completely changed in order to support
more efficient reconfigurations. If you are using sandboxfs with Bazel,
you will need to upgrade to Bazel 3.0.0 to use this version. See below for
more details on how the protocol has changed. -
Made sandboxfs process reconfiguration requests in parallel, which has a
significant performance impact when those requests are large. -
Fixed a bug where writes on a file descriptor that had been duplicated and
closed did not update the file size, resulting in bad data being returned
on future reads. -
Fixed timestamp updates so that the
birthtimerolls back to an older
mtimeto mimic BSD semantics. -
Fixed hardlink counts so that they are zero for handles that point to
deleted files or directories. -
Added support for extended attributes. Must be explicitly enabled by
passing the--xattrsoption. -
Added support to change the timestamps of a symlink on systems that have
this feature. -
Disabled the path-based node cache by default and added a
--node_cache
flag to reenable it. This fixes crashes when running Java within a
sandboxfs instance where the Java toolchain is mapped under multiple
locations and the first mapped location vanishes. See
The OSXFUSE, hard links, and dladdr puzzle
for details.
The following are the highlights of the changes to the reconfiguration protocol
in this release. You can read the full specification in the sandboxfs(1)
manual page:
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Use JSON streams for both the requests and the responses, instead of
the previous ad-hoc line-oriented protocol. -
Each map and unmap request carries a list of mappings to map and
unmap, respectively, along with the "root" path where all those mappings
start. This is to allow sandboxfs to process the requests more
efficiently. -
Each request contains a tag, which is then propagated to the response
for that request. This is to allow sandboxfs to process requests in
parallel. -
Work at the level of sandboxes, not paths, where a sandbox is defined
as a top-level directory with a collection of mappings beneath it.This essentially makes reconfigurations less powerful than they were, but
also makes them infinitely simpler to understand and manage. Furthermore,
this lines up better with the needs of Bazel, our primary customer, and
with sandboxfs' own name. -
Take prefix-encoded paths to minimize the size of the reconfiguration
requests. This has shown to significantly reduce the CPU consumption of
both sandboxfs and Bazel during a build, as the size of the reconfiguration
messages is drastically smaller. -
Accept short aliases for all fields, thus further minimizing the size
of reconfiguration requests, and also to accept omitting optional fields.