[LU-17423] Upstream dir_data feature

Related — Tue, 30 Jan 2024 15:09:27 +0000

The data-in-dirent patch was being discussed for upstream inclusion for 64-but inode support, but eventually that was not accepted because the 64-bit inode patch was only partially tested (ie. it built and didn't break 32-bit inodes, but had code and testing gaps for actual 64-bit inode numbers).

Landing the dirdata patch has now become more complex because the "fscrypt+case-insensitive" features are now storing extra information after the name in the dirent. This would have been a perfect case to use dirdata and get it included, except Google had already started using this in Android and didn't want to update the format, so there needs to be additional compatibility added for this case.

An agreed-upon proposal to get dirdata accepted without the Lustre kernel dependency is to add a dedicated test ioctl interface to store dirdata in directory entries, and confirm that it is being handled properly (eg. across rename, with e2fsck, etc). For compatibility with Lustre, this could store the "inode|generation" into the Lustre FID slot, since this is equivalent to an IGIF FID, and is also easy to verify later.

Whamcloud Community JIRA

[LU-17423] Upstream dir_data feature