fuse: interrupt handling framework

- add sub-framework to send timed responses to kernel
- add interrupt handler queue
- implement INTERRUPT

fuse_interrupt looks up handlers for interrupted messages
in the queue. If found, it invokes the handler function.
Else responds with EAGAIN with a delay.

See spec at

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/fuse.txt?h=v4.17#n148

and explanation in comments.

Change-Id: I1a79d3679b31f36e14b4ac8f60b7f2c1ea2badfb
updates: #465
Signed-off-by: Csaba Henk <csaba@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/libglusterfs/src/timespec.c b/libglusterfs/src/timespec.c
index d17506662ac..c0d4ab9315b 100644
--- a/libglusterfs/src/timespec.c
+++ b/libglusterfs/src/timespec.c
@@ -90,3 +90,19 @@ timespec_sub(const struct timespec *begin, const struct timespec *end,
         res->tv_nsec = end->tv_nsec - begin->tv_nsec;
     }
 }
+
+int
+timespec_cmp(const struct timespec *lhs_ts, const struct timespec *rhs_ts)
+{
+    if (lhs_ts->tv_sec < rhs_ts->tv_sec) {
+        return -1;
+    } else if (lhs_ts->tv_sec > rhs_ts->tv_sec) {
+        return 1;
+    } else if (lhs_ts->tv_nsec < rhs_ts->tv_nsec) {
+        return -1;
+    } else if (lhs_ts->tv_nsec > rhs_ts->tv_nsec) {
+        return 1;
+    }
+
+    return 0;
+}