EXT4 Finally Picking Up Support For The Common Get/Set Label Ioctls

It looks like EXT4 with Linux 5.17 will finally be supporting the FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls that several other prominent file-systems have been supporting the past few years.

FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL are ioctls for online reading and setting the file-system label for supported and mounted file-systems. These ioctls originally started out as specific ioctls for the Btrfs file-system but since Linux 4.18 were made generic. The ioctls were merged to the kernel's VFS area to allow this common interface for reading/setting the file-system label by user-space software without having to worry about file-system particulars. In turn file-systems like XFS and F2FS have also picked up FS_IOC_GETFSLABEL/FS_IOC_SETFSLABEL support and carrying it in the mainline kernel going back to 2019.

Now thanks to Red Hat's Lukas Czerner, EXT4 is joining the party in supporting the SETFSLABEL/GETFSLABEL functionality.

After floating the patch for review the past few months, Ted Ts'o has queued the patch now into EXT4's "dev" branch. With Linux 5.17 right ahead and the EXT4 patches having not yet been cut for that next merge window, it looks like v5.17 will be the kernel to finally offer this functionality on EXT4.