Linux 7.3 KSMBD Adds Interoperability For Apple Time Machine Backups

KSMBD as the in-kernel SMB3/CIFS server for higher performance and lower resource usage than user-space SMB/CIFS protocol implementations is becoming even more useful with the in-development Linux 7.3 kernel.

KSMBD now boasts opt-in support for Apple Time Machine integration. This allows Apple Time Machine backups over SMB via backupd to use a Linux KSMBD server for backing up data. This comes as there are a number of Apple SMB extensions it relies upon that until now were unsupported by Linux KSMBD.

The Apple "AAPL" SMB2 extensions include Finder, stream, COPYCHUNK, sparse-file, CHANGE_NOTIFY, and RPC compatibility bits. With code authored by Gael Blivet, enough of these Apple extensions are implemented to satisfy Apple TIme Machine interfacing with KSMBD.

These Apple extensions are not publicly documented and had to be reverse-engineered from client/server behavior. Thus this support is opt-in at least for the time being.

KSMBD in Linux 7.3 also implemented SMB2 command sequence window support, SMB3 request replay support, per-share SMB3 encryption support, and SMB Direct RDMA encryption support.

More details on these new features as well as many fixes to this Linux in-kernel SMB server via this pull.

Meanwhile there was also the SMB client updates merged this week for Linux 7.3. There are a collection of thirty-three client fixes. No major feature changes queued up there as Paulo Alcantara took over abruptly following the unfortunate and unexpected passing of maintainer Steve French.