On Wed, Jan 15, 2014 at 10:17:49AM -0500, J. Bruce Fields wrote: > From: "J. Bruce Fields" <bfields@xxxxxxxxxx> > > d_splice_alias can create duplicate directory aliases (in the !new > case), or (in the new case) d_move without holding appropriate locks. > > d_materialise_unique deals with both of these problems. (The latter > seems to be dealt by trylocks (see __d_unalias), which look like they > could cause spurious lookup failures--but that's at least better than > corrupting the dcache.) I'm a bit worried about those spurious failures, maybe we should retry in that case? Also looking over the changes I wonder if the explicit cecking for aliases for every non-directory might have a major performance impact, all the dcache growling already was a major issues in NFS workloads years ago and I dumb it's become any better. Also looking at this area I'd like to suggest that if you end up merging the two I'd continue using the d_splice_alias name and calling conventions. Also the inode == NULL case really should be split out from d_materialise_unique into a separate helper. It shares almost no code, is entirely undocumented to the point that I don't really understand what the purpose is, and the only caller that can get there (fuse) already branches around that case in the caller anyway. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
