custom etag for dav module

[Joel Ebel <jb...@google.com>]

Apache core supports a FileETag directive to customize the attributes
that go into creating an etag.  In our case, since we have multiple
backends, using the inode as part of the etag is not useful, so we
removed it.  However, we also recently attempted to use davfs2 fuse
filesystem with apache, and found the clearly documented note that
apache's mod_dav_fs doesn't support customized etags.  Since davfs2
uses PROPFIND for directory listings (using mod_dav_fs and a hard
coded etag with inode) and GET for actual file retrieval (using core,
and thus the customized etag with no inode) it sees the etag as having
changed and invalidates its cache of the file on every directory
listing.

My question is if there's any justification for why mod_dav_fs hard
codes the etag to include inode, or if this would be a reasonable bug
report or patch for it to respect the FileETag directive as well.  I
see this suggested as part of discussion of a different issue here:
http://mail-archives.apache.org/mod_mbox/httpd-dev/200710.mbox/%3C470E9A9F.8020202@pearsoncmg.com%3E
but I don't see any evidence that anything happened with it.

Joel