I recently updated one of my servers from an older 4.19 Linux kernel to the latest 5.5 kernel mainly because of the many filesystem improvements, just to find that some of my filesystems simply cannot be mounted anymore. The kernel reports: EXT4-fs: unsupported inode size: 4096 Here is a simple test to reproduce the issue: truncate --size 16G data losetup /dev/loop0 data mkfs.ext4 -I 4096 /dev/loop0 mount /dev/loop0 /media [33700.299204] EXT4-fs (loop0): unsupported inode size: 4096 Note: this works perfectly fine und 4.19.84 and 4.14.145. My guess so far is that somehow the ext4 filesystem now checks that the inode size is not larger than the logical block size of the underlying block device. # cat /sys/block/loop0/queue/logical_block_size 512 Note that the logical block size is also 512 on many SATA drives which have a physical block size of 4096. Any ideas how to address this problem and get the file- systems to mount under Linux 5.5? Many thanks in advance, Herbert