NFS: Do uncached readdir when we're seeking a cookie in an empty page cache
If the directory is changing, causing the page cache to get invalidated while we are listing the contents, then the NFS client is currently forced to read in the entire directory contents from scratch, because it needs to perform a linear search for the readdir cookie. While this is not an issue for small directories, it does not scale to directories with millions of entries. In order to be able to deal with large directories that are changing, add a heuristic to ensure that if the page cache is empty, and we are searching for a cookie that is not the zero cookie, we just default to performing uncached readdir. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Please register or sign in to comment