From: Chuck Lever <chuck.lever@xxxxxxxxxx>
RFC 7862 states that if an NFS server implements a CLONE operation,
it MUST also implement FATTR4_CLONE_BLKSIZE. NFSD implements CLONE,
but does not implement FATTR4_CLONE_BLKSIZE.
Note that in Section 12.2, RFC 7862 claims that
FATTR4_CLONE_BLKSIZE is RECOMMENDED, not REQUIRED. Likely this is
because a minor version is not permitted to add a REQUIRED
attribute. Confusing.
NFSD can return 0 here, as at least one client implementation we
are aware of (the Linux NFS client) treats 0 as meaning "CLONE has
no alignment restrictions".
Meanwhile we need to consult the nfsv4 Working Group to clarify the
meaning and use of the value of this attribute.
Reported-by: Roland Mainz <roland.mainz@xxxxxxxxxxx>
X-Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/nfs4xdr.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index e67420729ecd..44e7fb34f433 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3391,6 +3391,13 @@ static __be32 nfsd4_encode_fattr4_suppattr_exclcreat(struct xdr_stream *xdr,
return nfsd4_encode_bitmap4(xdr, supp[0], supp[1], supp[2]);
}
+static __be32 nfsd4_encode_fattr4_clone_blksize(struct xdr_stream *xdr,
+ const struct nfsd4_fattr_args *args)
+{
+ /* Linux filesystems have no clone alignment restrictions */
+ return nfsd4_encode_uint32_t(xdr, 0);
+}
+
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
static __be32 nfsd4_encode_fattr4_sec_label(struct xdr_stream *xdr,
const struct nfsd4_fattr_args *args)
@@ -3545,7 +3552,7 @@ static const nfsd4_enc_attr nfsd4_enc_fattr4_encode_ops[] = {
[FATTR4_MODE_SET_MASKED] = nfsd4_encode_fattr4__noop,
[FATTR4_SUPPATTR_EXCLCREAT] = nfsd4_encode_fattr4_suppattr_exclcreat,
[FATTR4_FS_CHARSET_CAP] = nfsd4_encode_fattr4__noop,
- [FATTR4_CLONE_BLKSIZE] = nfsd4_encode_fattr4__noop,
+ [FATTR4_CLONE_BLKSIZE] = nfsd4_encode_fattr4_clone_blksize,
[FATTR4_SPACE_FREED] = nfsd4_encode_fattr4__noop,
[FATTR4_CHANGE_ATTR_TYPE] = nfsd4_encode_fattr4__noop,
--
2.49.0
