Linux 5.18 Makes Two Key Improvements To exFAT File-System Support
Ahead of the Linux 5.18 merge window ending this weekend, the driver for Microsoft's exFAT file-system saw its pull request today. There are just two patches this cycle for exFAT but both changes are significant.
The Linux 5.18 exFAT file-system driver updates include just two patches but at least are notable alterations.
First, exFAT on Linux 5.18+ adds an option to allow access to paths with trailing dots. Up to now the exFAT driver unconditionally stripped out trailing periods from path components while with Linux 5.18 that is being loosened up. The patch adds an exFAT "keep_last_dots" mount option to control whether or not trailing periods are stripped. This work was motivated by discovering that the FUSE exFAT driver allows trailing dots fine but the Linux kernel driver does not. More details in this patch.
The other patch for Linux 5.18 no longer clears VolumeDirty in writeback and important change to avoid shortening the life of the storage device.
Before this commit, VolumeDirty will be cleared first in writeback if 'dirsync' or 'sync' is not enabled. If the power is suddenly cut off after cleaning VolumeDirty but other updates are not written, the exFAT filesystem will not be able to detect the power failure in the next mount.
And VolumeDirty will be set again but not cleared when updating the parent directory. It means that BootSector will be written at least once in each write-back, which will shorten the life of the device.
That's it for the exFAT pull in Linux 5.18.