On Mon, Oct 14, 2024 at 04:42:07PM +0000, Jaegeuk Kim wrote: > > > > Plz, refer to this patch and the description there. > > > > https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git/commit/?h=dev-test&id=8cc4e257ec20bee207bb034d5ac406e1ab31eaea > > Also, I added this in the description. > > --- > For example, > "mkfs.f2fs -c /dev/block/test@test_alias /dev/block/main" gives > a file $root/test_alias which carves out /dev/block/test partition. What partition? So mkfs.f2fs adds additional devices based on the man page. So the above creates a file system with two devices, but the second device is not added to the general space pool, but mapped to a specific file? How does this file work. I guess it can't be unlinked and renamed. It probably also can't be truncated and hole punched, or use insert/collapse range. How does the user find out about this magic file? What is the use case? Are the exact semantics documented somewhere?