rename of hardlinked files

[Steven French]

One of the connectathon POSIX file subtests does a rename of fileA to fileB
where fileA and fileB are hardlinked.   For POSIX this is supposed to be a
noop, but Samba (and Windows) return STATUS_NAME_COLLISION which causes the
Linux cifs client (which does not realize that they are hardlinked) to
delete the target and retry the rename.   Since the rename smb op (and the
SMB NT Rename as well) only have a 16 bit attributes field passed on the
request, it does not look like the trick of passing ATTR_POSIX_SEMANTICS
would work (since it is an attribute flag in the range above 64K which can
only be passed in 32 bit attribute fields such as what NTCreate allows).

Ideas?

Negotiating a posix dialect would work for Samba to be able to respond
differently (such code for negotiating a new dialect is ifdef out currently
in the 2.6.7pre Linux CIFS client), but there may be a better way - I might
be able to save off Samba's inode number (returned on UNIXQPathInfos - but
can it be relied upon to match when returned over the existing CIFS Unix
extensions?) and compare after the failure - but it could add to the size
of the existing inode struct which would be expensive in memory on the
client (lots of inode structs get cached).


Steve French
Senior Software Engineer
Linux Technology Center - IBM Austin
phone: 512-838-2294
email: sfrench at-sign us dot ibm dot com