I'm thinking of adding support to the NFS client code so that the open_by_handle_at(2) and name_to_handle_at(2) services would work on NFS mounted file systems. As far as I can tell, this support currently doesn't exist in mainline, correct? Many years ago I created and still maintain (unreleased) code for RHEL4-RHEL6 kernels that provide open-by-file-handle services for NFS clients. The approach was loosely based on Robert Love's ext3 open-by-inode patch of long ago. We have used the modified NFS client code as a significant performance boost in accessing mostly read-only files from NFS file servers. The files number in the many 10s of millions in trees spread across many hundreds of thousands of nested directories. (Come to think of it, that was several years ago. I'm sure since then the numbers have grown by at least an order of magnitude or two.) With the sheer numbers of files and directories, attempting to use even openat(2) with all those directories would still be overwhelming to the servers' inode cache. Also, just doing all the constant tree-walks down to the files kill performance and stresses the dentry cache, let alone all the network traffic and load on our filers that would generate. So that's why an open-by-file-handle hack was added to our kernels. Now the time has come for that functionality to be ported to a RHEL7-based kernel. Seems to me the best approach would be not to port my old work forward but to complete the fhandle callbacks for NFS clients. However, before I begin my journey down that path, I'd like to hear if anyone has tried it before, or if there's a good reason not to choose this approach. Any comments? If the NFS client fhandle support is the right way to go, since it wouldn't be a hackfest like my previous effort, I'd attempt contribute it upstream in case anyone else would ever find it useful. Quentin -- 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
