Dear Maintainer,

Using fuse-overlayfs on tmpfs (/dev/shm/[folder]) causing system to
freeze during suspend / resume cycle. With kernel message:

[60730.265604] task:systemd-sleep state:D stack:0 pid:88748 ppid:1
flags:0x00004002
[60730.267480] Call Trace:
[60730.269418] <TASK>
[60730.271199] __schedule+0x351/0xa20
[60730.273102] ? __ia32_sys_tee+0xd0/0xd0
[60730.274827] schedule+0x5d/0xe0
[60730.276542] wb_wait_for_completion+0x82/0xb0
[60730.278412] ? dequeue_task_stop+0x70/0x70
[60730.280135] sync_inodes_sb+0xda/0x2b0
[60730.281958] ? __ia32_sys_tee+0xd0/0xd0
[60730.283632] iterate_supers+0x85/0xe0
[60730.285397] ksys_sync+0x40/0xa0
[60730.287002] ksys_sync_helper+0x13/0x80
[60730.288597] pm_suspend.cold+0x126/0x35e
[60730.290276] state_store+0x68/0xd0
[60730.291765] kernfs_fop_write_iter+0x11b/0x1f0
[60730.293304] vfs_write+0x241/0x400
[60730.294638] ksys_write+0x6b/0xf0
[60730.295916] do_syscall_64+0x58/0xc0
[60730.297302] ? exit_to_user_mode_prepare+0x3c/0x1c0
[60730.298552] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[60730.299869] RIP: 0033:0x7f74082f4190
[60730.301228] RSP: 002b:00007fff12152e88 EFLAGS: 00000202 ORIG_RAX:
0000000000000001
[60730.302451] RAX: ffffffffffffffda RBX: 0000000000000004 RCX:
00007f74082f4190
[60730.303688] RDX: 0000000000000004 RSI: 00007fff12152f70 RDI:
0000000000000004
[60730.304731] RBP: 00007fff12152f70 R08: 0000000000000007 R09:
0000558b894ce590
[60730.305098] R10: f664a9c3885c4633 R11: 0000000000000202 R12:
0000000000000004
[60730.305447] R13: 0000558b894cc2d0 R14: 0000000000000004 R15:
00007f74083ca9e0
[60730.305780] </TASK>

Steps to reproduce:

mkdir -p /dev/shm/test/up
mkdir -p /dev/shm/test/tmp
mkdir -p /dev/shm/test/data

fuse-overlayfs -o
"static_nlink,noacl,upperdir=/dev/shm/test/up,lowerdir=$HOME/.mozilla/firefox/,workdir=/dev/shm/test/tmp"
/dev/shm/test/data

firefox --profile /dev/shm/test/data/c9933.default

systemctl suspend