lxcfs: explicitly enable direct_IO for libfuse3

It was discovered that with libfuse3 we lost FOPEN_DIRECT_IO flag
on (struct fuse_file)->open_flags. I'm sure that this is the reason
for all the strange bugs that our users met recently.

Fixes:
https://github.com/lxc/lxcfs/issues/565
https://discuss.linuxcontainers.org/t/number-of-cpus-reported-by-proc-stat-fluctuates-causing-issues/15780/14

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

diff --git a/src/lxcfs.c b/src/lxcfs.c
index fed896c965835ae14c4dc1219aff6b3297035cf0..5c0f70d17d992d5c99c7d3b628a79dad0462f5ea 100644 (file)
--- a/src/lxcfs.c
+++ b/src/lxcfs.c
@@ -1030,6 +1030,10 @@ static void *lxcfs_init(struct fuse_conn_info *conn)
        if (lxcfs_init_library() < 0)
                return NULL;
 
+#if HAVE_FUSE3
+       cfg->direct_io = 1;
+#endif
+
        return fuse_get_context()->private_data;
 }