Hi, Negative dentry is a VFS concept where it maintains a cache of dentries even for files that do not exist. This can come in handy for situations where they are looked up. For example, many applications first check the existence of a file before creating it. Ideally, negative dentries should allow a filename lookup to happen entirely from the dentry cache if the lookup had happened once already. But I noticed that the SMB client goes to the server every time we do a stat of a file that does not exist. I investigated this more and it looks like vfs_getattr does make use of negative dentry, but the revalidate always comes to cifs_d_revalidate even for negative dentries. And we do not have the code necessary to deal with it. We do use d_really_is_positive before we do the dentry validation, but it looks like that comes to us as success, even in case of non-existent dentries. Is this expected? I compared the revalidate code on the NFS client, and it does look like nfs_neg_need_reval deals with this situation based on some heuristics. -- Regards, Shyam
