This repository is cloned from the last CVS snapshot of
Fix for a race condition in multi-threaded mode (see #4).
This is a binding to fuse for the ocaml programming language, enabling
you to write multithreaded filesystems in the ocaml language. It has
been designed with simplicity as a goal, as you can see by looking at
example/fusexmp.ml. Efficiency has also been a separate goal. The
Bigarray library is used for read and writes, allowing the library to
do zero-copy in ocaml land.
You need fuse (version 2.7 or greater)
You also need ocaml >= 4.02.3 and camlidl >= 1.05.
The reccomended way to install this library is using
opam install ocamlfuse
If you don't want to install OPAM, you need to manually install this
Should be in the major linux distributions, but you can find it at
You need to install
libfuse-devin debian and ubuntu.
OCaml >= 4.02.3
Should be there in the major linux distributions, but is also available at
CamlIDL >= 1.05
present at least in ubuntu, also available at
dune >= 1.6
unpack the tarball, then
make make install
This will install ocamlfuse in your ocaml library directory. To uninstall
it you can use "make uninstall"
make example cd _build/default/example mkdir tmp ./fusexmp.exe tmp cd tmp #you'll find a copy of your "/" directory here
NOTE: if you access the "clone" of the mountpoint of the filesystem, the fs will hang (kill it and then use fusermount -u to umount it). This is a known bug/limitation.
BEFORE YOU WRITE YOUR OWN FILESYSTEM
KNOWN PROBLEMS (if you can help, please do)
The stateful interface for readdir is not implemented
There is a stub in Fuse_util.c regarding st_blocks - if one
implements statfs with a block size different
than 512 "du" will not work on the filesystem.
many ocaml exceptions are reported as 127
we should add non-blocking lstat64 and statfs,*xattr implementations for
ocaml in Unix_util
translation between ocaml unix errors and C unix error is dependent
on the order of constructor names in ocaml. There should be a way to
get error names from caml and create a translation table.
the Unix_util library uses unsafe coercions between unix file
handles (which are defined as ints) and ints. Even if this works, in
the future it might stop working.
IMPORTANT: Unix_util.read and write operations have not been tested
in case of errors. Error code conversion might be incorrect but I
don't have test cases (maybe the easy way is to modify fusexmp to
return various errors).
Unix errors which are unknown to ocaml should be reported as EUNKNOWNERR
Test statfs (never used until now)
Some errors are missing in the unix module (e.g. ENOTSUP,ENOATTR,
see man lsxattr). We could solve all these problems with errors using
a custom error type instead of unix_error but this would create
deadlock (and consequent necessity to kill -KILL the program) if
accessing the mountpoint mirrored inside the mountpoint in
fusexmp. I remember it was easy to understand why, but right now I
have no idea.
HELPING THE PROJECT
The best help you can give to the project is to test everything,
including, but not limited to:
large file operations (files >= 4gb)
multithreaded operations: the filesystem should always be responsive,
no matter if reading a certain file blocks
robustness: the filesystem should NEVER exit from its mainloop if not
explicitly requested from the user.
Please report if you do serious tests! We need to know which programs
did you use, if you found any bug, and how to reproduce the tests.
Also, we need packaging, I don't have the necessary time and don't know
ocamlfindlib or GODI. Please if you have the time and the necessary
knowledge help with packaging. Autoconf support would be highly appreciated,
A mailing list has been set up on sourceforge, you are strongly
encouraged to post feedback there and in general to subscribe if you use ocamlfuse.
The sourceforge page for ocamlfuse is
Bye and have fun
vincenzo_ml at yahoo dot it
ciancia at di dot unipi dot it
applejack at users dot sourceforge dot net