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By Zayden R., September 20, 2026
Linux 7.3-rc4 addresses a Btrfs FSID regression and GRUB2 boot problems. Engineers should update to regain stable FSID function and proper GRUB2 detection in initramdisk-less systems.
Linux 7.3-rc4 brings crucial fixes to the Btrfs file-system, addressing two significant bugs that have impacted users since earlier release candidates. The most pressing of these is a regression from Linux 7.2-rc1 that altered how the fs_fsid identifier was derived, breaking backwards compatibility and affecting user-space applications. This regression particularly disrupted applications like NetworkManager OpenConnect, where VPN access was compromised due to changing FSIDs across reboots.
With the latest release candidate, the FSID derivation reverts to using the file-system UUID, restoring stability for applications relying on a consistent FSID. This is a solid improvement, ensuring that user-space applications can function without unexpected interruptions following kernel updates.
The second fix targets an issue present in the Linux 7.3 development cycle that affected systems booting without an initramfs. GRUB2 failed to detect the root file-system device on Btrfs setups, causing boot failures. This fix means that systems using GRUB2 can now properly detect /dev/root and boot without an initramdisk, a relief for sysadmins who prefer or require initramdisk-less configurations.
These updates are part of a broader set of Btrfs file-system fixes merged ahead of the Linux 7.3-rc4 release. Engineers running affected systems should consider updating to this release candidate to benefit from these improvements and ensure smoother operation of their Btrfs file-systems.