[ceph-users] ceph-fuse false passed X_OK check

Hi Cephers, I'm using VSCode remote development with a docker server. It worked OK but fails to start the debugger after /root mounted by ceph-fuse. The log shows that the binary passes access X_OK check but cannot be actually executed. see: ``` strace_log: access("/root/.vscode-server/extensions/ms-vscode.cpptools-1.1.3/debugAdapters/OpenDebugAD7", X_OK) = 0 root@develop:~# ls -alh .vscode-server/extensions/ms-vscode.cpptools-1.1.3/debugAdapters/OpenDebugAD7 -rw-r--r-- 1 root root 978 Dec 10 13:06 .vscode-server/extensions/ms-vscode.cpptools-1.1.3/debugAdapters/OpenDebugAD7 ``` I also test the access syscall on ext4, xfs and even cephfs kernel client, all of them return -EACCES, which is expected (the extension will then explicitly call chmod +x). After some digging in the code, I found it is probably caused by https://github.com/ceph/ceph/blob/master/src/client/Client.cc#L5549-L5550. So here come two questions: 1. Is this a bug or is there any concern I missed? 2. It works again with fuse_default_permissions=true, any drawbacks if this option is set?