NOTE: This info is not relevant to the near-term Fedora merge or any infrastructure supporting it. We will continue to use the existing CVS + ACL system.
Toshio was wondering about the possibility of using filesystem ACL's as part of a future ideal SCM's ACL enforcement. It would work something like this: 1) PackageDB knows about all packages, owners, granted permissions, groups, etc. 2) PackageDB generates xattrs or FS ACL (themselves based on xattrs) within the SCM files/directories. 3) SCM has a custom ACL enforcement script that reads those xattrs, making it very fast and flexible. ACL's could be enforced based on a list of users, groups, or a combination of users and groups.
I talked with a few filesystem experts within Red Hat. They said... - ext3 has a limit of 4KB for xattr data. If you use the standard encoding of 8 bytes per uid, that has a limit of roughly 100 entities that could be associated with a file. Is this too limiting? I dunno. Perhaps it need not be too limiting if more extensive use of group-based-ACL's are used. - XFS could possibly allow a maximum of 64KB xattr's per file, but that is very inefficient in filesystem storage. - xattr's are currently not supported by NFS.
Warren Togami wtogami@redhat.com