On Wed, Jun 16, 2021 at 03:14:17PM +0000, Trond Myklebust wrote: > The setxattr() manpage appears to suggest ERANGE is the correct return > value here. > > ERANGE The size of name or value exceeds a filesystem-specific > limit. > > > However I can't tell if ext4 and xfs ever do that. Furthermore, it > looks as if the VFS is always returning E2BIG if size > XATTR_SIZE_MAX. > The basic issue here is that there are two limits: the generic one (XATTR_SIZE_MAX), and the fs-specific one. When crossing the generic one, the xattr code returns E2BIG. When crossing the fs-specific one, it looks like there are a few filesystems that return E2BIG, but others (like ext4) return ENOSPC. For the server, NFS4ERR_XATTR2BIG is the right value to return for all these cases. For the generic limit, it's an easy check. For the fs-specific limit, the server code doesn't necessarily know what's going on, since filesystems don't have a way to advertise their limits. So ENOSPC will *probably* mean that the attribute was too large for the filesystem, but it might not. You could change the server code to translate ENOSPC to NFS4ERR_XATTR2BIG. But that might not be totally correct either, you're going to end up returning an error to the client that is not correct in all cases either way. The problem here for xfstests is how to define the 'correct' behavior across all filesystems so that there's a clean pass/fail, as long as these inconsistencies exist. - Frank
