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FUSEFS(5)		    BSD	File Formats Manual		     FUSEFS(5)

NAME
     fusefs -- File system in USErspace

SYNOPSIS
     To	link into the kernel:

	   options FUSEFS

     To	load as	a loadable kernel module:

	   kldload fusefs

DESCRIPTION
     The fusefs	driver implements a file system	that is	serviced by a
     userspace program.

     There are many uses for fusefs.  Userspace	daemons	can access libraries
     or	programming languages that cannot run in kernel-mode, for example.
     fusefs is also useful for developing and debugging	file systems, because
     a crash of	the daemon will	not take down the entire operating system.
     Finally, the fusefs API is	portable.  Many	daemons	can run	on multiple
     operating systems with minimal modifications.

SYSCTL VARIABLES
     The following sysctl(8) variables are available:

     vfs.fusefs.kernelabi_major
	     Major version of the FUSE kernel ABI supported by this driver.

     vfs.fusefs.kernelabi_minor
	     Minor version of the FUSE kernel ABI supported by this driver.

     vfs.fusefs.data_cache_mode
	     Controls how fusefs will cache file data for pre-7.23 file	sys-
	     tems.  A value of 0 will disable caching entirely.	 Every data
	     access will be forwarded to the daemon.  A	value of 1 will	select
	     write-through caching.  Reads will	be cached in the VFS layer as
	     usual.  Writes will be immediately	forwarded to the daemon, and
	     also added	to the cache.  A value of 2 will select	write-back
	     caching.  Reads and writes	will both be cached, and writes	will
	     occasionally be flushed to	the daemon by the page daemon.	Write-
	     back caching is usually unsafe, especially	for FUSE file systems
	     that require network access.

	     FUSE file systems using protocol 7.23 or later specify their
	     cache behavior on a per-mountpoint	basis, ignoring	this sysctl.

     vfs.fusefs.stats.filehandle_count
	     Current number of open FUSE file handles.

     vfs.fusefs.stats.lookup_cache_hits
	     Total number of lookup cache hits.

     vfs.fusefs.stats.lookup_cache_misses
	     Total number of lookup cache misses.

     vfs.fusefs.stats.node_count
	     Current number of allocated FUSE vnodes.

     vfs.fusefs.stats.ticket_count
	     Current number of allocated FUSE tickets, which is	roughly	equal
	     to	the number of FUSE operations currently	being processed	by
	     daemons.

SEE ALSO
     mount_fusefs(8)

HISTORY
     The fuse driver was written as the	part of	the FreeBSD implementation of
     the FUSE userspace	file system framework (see
     https://github.com/libfuse/libfuse) and first appeared in the
     sysutils/fusefs-kmod port,	supporting FreeBSD 6.0.	 It was	added to the
     base system in FreeBSD 10.0, and renamed to fusefs	for FreeBSD 12.1.

AUTHORS
     The fuse driver was originally written by Csaba Henk as a Google Summer
     of	Code project in	2005.  It was further developed	by Ilya	Putsikau dur-
     ing Google	Summer of Code 2011, and that version was integrated into the
     base system by Attilio Rao	<attilio@FreeBSD.org>.

     This manual page was written by Alan Somers <asomers@FreeBSD.org>.

BSD				 July 31, 2019				   BSD

NAME | SYNOPSIS | DESCRIPTION | SYSCTL VARIABLES | SEE ALSO | HISTORY | AUTHORS

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