[Please keep replies on the mailing list so that others can benefit] On Tue, Oct 17, 2017 at 10:07:31PM +0300, Maxim Kozover wrote:
Hi Richard, Unfortunately I achieved a negative result, maybe you could help, please? . I'm using libguestfs-1.36.4 as a base since I changed for myself a bit some detection stuff that you recently moved from C to OCaml and I can't rewrite it immediately.
WIth vanilla 1.36.4 just changing fuse_loop to fuse_loop_mt gives almost immediate crash when the filesystem is accessed.
That's expected because plain 1.36 doesn't support multithreading, but ...
I've put the most recent gnulib, changed a bit bootstrap etc, put the patches from https://www.redhat.com/archives/libguestfs/2017-June/ msg00287.html and rebuilt.
... OK.
The system seems to work (with single-threaded fuse). Changed fuse_loop to fuse_loop_mt, rebuilt and fuse is stuck on the first call to appropriate fuse "system call" like mount_local_getattr in case of ls. It is stuck at guestfs_lstatns possibly at ACQUIRE_LOCK_FOR_CURRENT_SCOPE, while being called from fuse.
Can you get a stack trace from gdb. Use the command ‘t a a bt’ to show stacks from all threads at the same time.
What do you think could be a problem? Some lock already taken? Also, maybe less concern for me as I use fuse read-only, is the directory cache guarded?
Possibly not, I've not really looked at the fuse code w.r.t multithreading at all. Patches welcome as usual. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org