Linux storage

ForkPress uses Linux reflinks when the project filesystem supports them. If the project filesystem rejects reflinks, ForkPress can use a shared XFS loop volume as the copy-on-write fallback.

FICLONE reflinks

The default Linux path uses the FICLONE ioctl. New branch files share unchanged blocks with their source files until one branch writes to them.

The branch directories live directly in the project directory:

main/
marketing/
.forkpress/

Shared XFS loop fallback

When the project filesystem cannot reflink files, ForkPress expands an embedded reflink-capable XFS image under the user’s ForkPress data directory, attaches it to a loop device, and mounts one shared XFS volume for ForkPress sites.

Each site gets a stable storage directory inside that shared mount. Public branch directories remain visible in the project directory.

The setup uses Linux ioctls and mount(2) directly. It still requires permission to allocate loop devices and mount filesystems, usually root or CAP_SYS_ADMIN.

Mount lifecycle

Inspect storage:

forkpress storage status
forkpress doctor storage

Detach storage only after stopping other ForkPress sites that use the same shared XFS file view:

forkpress storage detach

Before deleting a Linux XFS-loop site, remove the site work dir, public branch symlinks, and hidden per-site directory inside the shared mount while storage is attached. forkpress storage detach prints the exact rm -rf command before it unmounts the shared volume.

du can over-count reflink sharing on XFS. Compare filesystem free space before and after branch operations when you need to measure physical growth.