[linux-cifs-client] [PATCH 2/2] cifs: fix busy-file renames and refactor cifs_rename logic

[Christoph Hellwig]

On Thu, Sep 04, 2008 at 10:45:26PM -0400, Jeff Layton wrote:
> Break out the code that does the actual renaming into a separate
> function and have cifs_rename call that. That function will attempt a
> path based rename first and then do a filehandle based one if it looks
> like the source is busy.
> 
> The existing logic tried a path based rename first, but if we needed to
> remove the destination then it only attempted a filehandle based rename
> afterward. Not all servers support renaming by filehandle, so we need to
> always attempt path rename first and fall back to filehandle rename if
> it doesn't work.
> 
> The renaming logic also wasn't quite right in some cases. If the source
> and target are hardlinked then it's not really a no-op (we still need to
> unlink the source).

Actually per posix rename _is_ a no-op if old and new are hardlinks to
same inode.  But this case is completely handled in the VFS, and
filesystems don't need to consider it at all.