Take a pass through fixing some of the most egregious whitespace issues in
fs/fuse. Also fix some style(9) warts while here. Not 100% cleaned up, but
somewhat less painful to look at and edit.
No functional change.
At least prior to 7.23 (which adds FUSE_WRITEBACK_CACHE), the FUSE protocol
specifies only clean data to be cached.
Prior to this change, we implement and default to writeback caching. This
is ok enough for local only filesystems without hardlinks, but violates the
general design contract with FUSE and breaks distributed filesystems or
concurrent access to hardlinks of the same inode.
In this change, add cache mode as an extension of cache enable/disable. The
new modes are UC (was: cache disabled), WT (default), and WB (was: cache
enabled).
For now, WT caching is implemented as write-around, which meets the goal of
only caching clean data. WT can be better than WA for workloads that
frequently read data that was recently written, but WA is trivial to
implement. Note that this has no effect on O_WRONLY-opened files, which
were already coerced to write-around.
Refs:
* https://sourceforge.net/p/fuse/mailman/message/8902254/
* https://github.com/vgough/encfs/issues/315
PR: 230258 (inspired by)
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
This has been developed during 2 summer of code mandates and being revived
by gnn recently.
The functionality in this commit mirrors entirely content of fusefs-kmod
port, which doesn't need to be installed anymore for -CURRENT setups.
In order to get some sparse technical notes, please refer to:
http://lists.freebsd.org/pipermail/freebsd-fs/2012-March/013876.html
or to the project branch:
svn://svn.freebsd.org/base/projects/fuse/
which also contains granular history of changes happened during port
refinements. This commit does not came from the branch reintegration
itself because it seems svn is not behaving properly for this functionaly
at the moment.
Partly Sponsored by: Google, Summer of Code program 2005, 2011
Originally submitted by: ilya, Csaba Henk <csaba-ml AT creo DOT hu >
In collabouration with: pho
Tested by: flo, gnn, Gustau Perez,
Kevin Oberman <rkoberman AT gmail DOT com>
MFC after: 2 months
