On Fri, Aug 7, 2020 at 9:55 PM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > fuse_file_put(sync) can be called with sync=true/false. If sync=true, > it waits for release request response and then calls iput() in the > caller's context. If sync=false, it does not wait for release request > response, frees the fuse_file struct immediately and req->end function > does the iput(). > > iput() can be a problem with DAX if called in req->end context. If this > is last reference to inode (VFS has let go its reference already), then > iput() will clean DAX mappings as well and send REMOVEMAPPING requests > and wait for completion. (All the the worker thread context which is > processing fuse replies from daemon on the host). > > That means it blocks worker thread and it stops processing further > replies and system deadlocks. Is this reasoning specific to DAX? Seems to me this is a virtio-fs specific issue. Thanks, Miklos
