On Thu, Jun 29, 2017 at 10:25:28AM -0700, Darrick J. Wong wrote: > Was there ever a version of NFS (or more generally callers of the > exportfs code) that couldn't deal with i_generation in the file handle, > and therefore we invented this generation hack to work around the loss > of the generation information? > > There's a comment in xfs_fs_encode_fh about not supporting 64bit inodes > with subtree_check (which seems to require one ino/gen pair for the file > and a second pair for the file's parent) on NFSv2 because v2 doesn't > provide enough space for all the file handle information, but that's the > furthest I got with lazy-mining the git history. :) There's a comment in fs/ext4/super.c:ext4_nfs_get_inode * Currently we don't know the generation for parent directory, so * a generation of 0 means "accept any" But I don't see that used. It was used once upon a time; I see it actually used in old 2.5 code in nfsd_get_dentry. Hm. --b.
