NFSv4: Fix a regression against the FreeBSD server

Technically, the Linux client is allowed by the NFSv4 spec to send
3 word bitmaps as part of an OPEN request. However, this causes the
current FreeBSD server to return NFS4ERR_ATTRNOTSUPP errors.

Fix the regression by making the Linux client use a 2 word bitmap unless
doing NFSv4.2 with labeled NFS.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 14 insertions, 7 deletions

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 0abfb8466e79..c74d6168db99 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -999,6 +999,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
         __be32 *p;
         __be32 *q;
         int len;
+        uint32_t bmval_len = 2;
         uint32_t bmval0 = 0;
         uint32_t bmval1 = 0;
         uint32_t bmval2 = 0;
@@ -1010,7 +1011,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
          * = 40 bytes, plus any contribution from variable-length fields
          *            such as owner/group.
          */
-        len = 20;
+        len = 8;
 
         /* Sigh */
         if (iap->ia_valid & ATTR_SIZE)
@@ -1040,8 +1041,6 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
                 }
                 len += 4 + (XDR_QUADLEN(owner_grouplen) << 2);
         }
-        if (label)
-                len += 4 + 4 + 4 + (XDR_QUADLEN(label->len) << 2);
         if (iap->ia_valid & ATTR_ATIME_SET)
                 len += 16;
         else if (iap->ia_valid & ATTR_ATIME)
@@ -1050,15 +1049,22 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
                 len += 16;
         else if (iap->ia_valid & ATTR_MTIME)
                 len += 4;
+        if (label) {
+                len += 4 + 4 + 4 + (XDR_QUADLEN(label->len) << 2);
+                bmval_len = 3;
+        }
+
+        len += bmval_len << 2;
         p = reserve_space(xdr, len);
 
         /*
          * We write the bitmap length now, but leave the bitmap and the attribute
          * buffer length to be backfilled at the end of this routine.
          */
-        *p++ = cpu_to_be32(3);
+        *p++ = cpu_to_be32(bmval_len);
         q = p;
-        p += 4;
+        /* Skip bitmap entries + attrlen */
+        p += bmval_len + 1;
 
         if (iap->ia_valid & ATTR_SIZE) {
                 bmval0 |= FATTR4_WORD0_SIZE;
@@ -1112,10 +1118,11 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
                                 len, ((char *)p - (char *)q) + 4);
                 BUG();
         }
-        len = (char *)p - (char *)q - 16;
+        len = (char *)p - (char *)q - (bmval_len << 2);
         *q++ = htonl(bmval0);
         *q++ = htonl(bmval1);
-        *q++ = htonl(bmval2);
+        if (bmval_len == 3)
+                *q++ = htonl(bmval2);
         *q = htonl(len);
 
 /* out: */