On Tue, Jan 2, 2024 at 12:16 PM shanthosh krishna moorthy <santy.accet@xxxxxxxxx> wrote: > > Hi, > > Is the Linux support for mounting overlay file system over another > overlayfs lowerdir still supported? > In kernel 4.1, this seems supported but not in 4.19 and above. > > //Create lower directoy on an overlayfs mount > root@device2:/# mkdir /lower /upper /work /merged > So /upper and /work are also on overlayfs? Even if it did work, I think that some operations may have unexpected results (creating opaque directory). > //User the 'lower' directory as lowerdir in overlayfs mount > root@device2:/# mount -t overlay overlay -o > lowerdir=/lower,upperdir=/upper,workdir=/work /merged > mount: /merged: wrong fs type, bad option, bad superblock on overlay, > missing codepage or helper program, or other error. > > root@device2:/# mount > ... > /dev/mmcblk0p9 on /overlay type ext4 (rw,noatime,nodelalloc,data=journal) > overlayfs:/overlay on / type overlay > (rw,noatime,lowerdir=/,upperdir=/overlay/bank_1,workdir=/overlay/work) > ... > root@device2:/# > > Could someone please shed some light on this error. The specific reason is to be found in the kernel log. It may indicate that some configs or mount options could help. Please check the difference in CONFIG_OVERLAY_FS* values in the two kernels you are comparing. Thanks, Amir.
