Use the -o intr mount option on FreeBSD (#462)

FUSE file systems normally indicate their interruptibility by returning
ENOSYS to the first FUSE_INTERRUPT operation.  But that causes two
problems for file systems that aren't interruptible:

1) A process may block on a signal, even if another thread could've
handled the signal.  The kernel must know whether the FUSE thread is
interruptible before deciding which thread should receive a signal.

2) The protocol allows a FUSE daemon to simply ignore FUSE_INTERRUPT
operations.  From the kernel's point of view, that is indistinguishable
from a FUSE_INTERRUPT operation arriving after the original operation
had already completed.  Thus, the kernel can't interpret an ignored
FUSE_INTERRUPT as an indication that the daemon is non-interruptible.

With the -o nointr mount option, no FUSE_INTERRUPT operations will ever
be sent.  Most FUSE file systems should require no modifications to take
advantage of this mount option.

diff --git a/lib/mount_bsd.c b/lib/mount_bsd.c
index f731cb68525ef081a509a46f7489bee3d1abf846..35f363452c74136e08976cbde564f3eb908f4866 100644 (file)
--- a/lib/mount_bsd.c
+++ b/lib/mount_bsd.c
@@ -86,6 +86,9 @@ static const struct fuse_opt fuse_mount_opts[] = {
        FUSE_DUAL_OPT_KEY("neglect_shares",     KEY_KERN),
        FUSE_DUAL_OPT_KEY("push_symlinks_in",   KEY_KERN),
        FUSE_OPT_KEY("nosync_unmount",          KEY_KERN),
+#if __FreeBSD_version >= 1200519
+       FUSE_DUAL_OPT_KEY("intr",               KEY_KERN),
+#endif
        /* stock FBSD mountopt parsing routine lets anything be negated... */
        /*
         * Linux specific mount options, but let just the mount util