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FUSEFS(4)		     Kernel Interfaces Manual		       FUSEFS(4)

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 systems.
	     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 ac-
	     cess.

	     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  during
     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>.

FreeBSD ports 15.1		  July 31, 2019 		       FUSEFS(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=fusefs&sektion=4&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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