There used to be an ext2 filesystem for AmigaOS available; it allowed you to read and write ext2 partitions. No new versions have been released in a while, however. Let me know if you know where to locate a copy.
Other ways to transfer files from Linux to AmigaOS are to use an msdos partition, an Amiga/PC formatted floppy with msdos file system (this requires a Mountlist entry on AmigaOS side), use of a partition with Minix file system and the Minix file handler on AmigaOS side (the driver is somewhat unstable) or by accessing the floppy or any (empty!) partition directly via GNU tar.
You can also read and write Amiga partitions from Linux (using the affs filesystem). Some older install guides say that affs is read-only, but that restriction was lifted in the 2.0 series of kernels (only Directory Cache disks are read-only now).
AmigaOS text files are normally formatted using ASCII Latin1 text; Linux normally defaults to using Latin1 encoding (also called ISO 8859-1), so you shouldn't have any problems. CR/LF problems should not appear either.