[intermittent] podman ps --size sometimes returns '0B', 'error unmounting' #3540
Description
Seeing this on f29 only; in particular, a non-dnf-upgraded f29. And only intermittently:
# podman run alpine true;podman run alpine dd if=/dev/zero of=/bigfile bs=1M count=10
10+0 records in
10+0 records out
# podman ps --size -a
ERRO[0000] error unmounting /var/lib/containers/storage/overlay/d90aed636ff383f7c3d36367864a87cea6e02e40e51e67913d7df5591553e53e/merged: invalid argument
ERRO[0000] error getting rw size for "25ed230c29166e2df5d6c01da29e4e385619b3378b366ba8a84c1c656b293fc3": error creating overlay mount to /var/lib/containers/storage/overlay/d90aed636ff383f7c3d36367864a87cea6e02e40e51e67913d7df5591553e53e/merged: device or resource busy
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES SIZE
25ed230c2916 docker.io/library/alpine:latest dd if=/dev/zero o... 2 seconds ago Exited (0) 2 seconds ago nifty_burnell 0B (virtual 5.58MB)
79415a40fc42 docker.io/library/alpine:latest true 3 seconds ago Exited (0) 3 seconds ago eloquent_noether 0B (virtual 5.58MB)
It only seems to happen when there are two containers; I haven't yet seen it with only one.
The '0B' thing is sporadic; sometimes it displays 10.5MB.
podman-1.4.4-2.fc29.x86_64; kernel 5.1.16-200.fc29.x86_64
I cannot reproduce on f30. This leads me to suspect that there's a dependency somewhere that needs to be updated. (And if this is the case, the RPM should be rebuilt to Require it). Any ideas on whether this seems plausible, and where I should begin checking?