Test failure: podman image-volume: ext2/ext3/ext4 mismatch

[edsantiago]

Pretty sure this is a logic failure in the test itself. It dates back to #22831. It fails on 1mt, but (apparently???) never in CI or gating:

✗ [160] podman --image-volume
...
[10:55:02.588334219] # podman run --image-volume anonymous --rm volume_image sh -c grep ' /data ' /proc/mounts | cut -f3 -d' '
   [10:55:02.979190999] ext4        
   #/vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
   #|     FAIL: Should match hosts graphroot fs                           
   #| expected: ext2/ext3                                                       
   #|   actual: ext4

The test code is hard to read, but here's a simple reproducer:

# stat -f $(podman info --format '{{.Store.GraphRoot}}')
  File: "/var/lib/containers/storage"
    ID: 1f1c00f584175bfd Namelen: 255     Type: ext2/ext3   <<<<< MAKE A NOTE OF THIS
Block size: 4096       Fundamental block size: 4096
Blocks: Total: 5135280    Free: 4533086    Available: 4303610
Inodes: Total: 1310720    Free: 1222081

# printf "FROM quay.io/libpod/testimage:20241011\nVOLUME /data\n" | podman build -t foo -q -
c8ccb37ea0b143024cf17dee633b6a2fd05d11f2b1f9d0d904c78a2ac173e6e2

# podman run --rm foo stat -f /data
  File: "/data"
    ID: 1f1c00f584175bfd Namelen: 255     Type: ext2/ext3    <<<< SAME
Block size: 4096      
Blocks: Total: 5135280    Free: 4533059    Available: 4303583
Inodes: Total: 1310720    Free: 1222055

# podman run --rm foo grep ' /data ' /proc/mounts
/dev/vda2 /data ext4 rw,seclabel,nosuid,nodev,relatime 0 0
                ^^^^------ OH NOES

Ed's tentative conclusion: we can't compare apples (output of stat) and oranges (/proc/mounts which comes from the kernel).

Fix in progress.