On Fri, Jul 11, 2025 at 12:21:11PM +0800, Michael Chang via Grub-devel wrote: > On Btrfs, GRUB cannot update the environment block (grubenv) because > file based writes via blocklists are incompatible with Btrfs COW (Copy > On Write) design. Although GRUB’s filesystem drivers are read only, > environment updates rely on raw block access to fixed locations, which > is not safe on Btrfs due to its dynamic block relocation. > > To address this, we introduce support for storing the GRUB environment > block in a fixed block within Btrfs reserved bootloader area, an unused > region in the device header intended for bootloader use. > > This patch adds fs_envblk helpers to grub-editenv for accessing the > reserved area directly. Variables that require runtime write access > during boot, such as next_entry, will be mirrored into this external > block. Other variables will remain stored in the file based grubenv so > they can keep per snapshot. > > The embedding logic is also updated to mark the reserved area as used to > avoid conflicts with embedded core images. > > This enables support for runtime environment updates on Btrfs root > volumes, allowing tools like grub-reboot to boot an entry once.
The commit message suggests the patch should be split at least into two or more patches. So, please do that and rebase... Daniel _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
