nfsd: rework NFS4_SHARE_WANT_* flag handling

The delstid draft adds new NFS4_SHARE_WANT_TYPE_MASK values that don't
fit neatly into the existing WANT_MASK or WHEN_MASK. Add a new
NFS4_SHARE_WANT_MOD_MASK value and redefine NFS4_SHARE_WANT_MASK to
include it.

Also fix the checks in nfsd4_deleg_xgrade_none_ext() to check for the
flags instead of equality, since there may be modifier flags in the
value.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: jtlayton

fs/nfsd/nfs4state.c

@@ -6224,10 +6224,10 @@ static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
 					struct nfs4_delegation *dp)
 {
 	if (deleg_is_write(dp->dl_type)) {
-		if (open->op_deleg_want == OPEN4_SHARE_ACCESS_WANT_READ_DELEG) {
+		if (open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_READ_DELEG) {
 			open->op_delegate_type = OPEN_DELEGATE_NONE_EXT;
 			open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
-		} else if (open->op_deleg_want == OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG) {
+		} else if (open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG) {
 			open->op_delegate_type = OPEN_DELEGATE_NONE_EXT;
 			open->op_why_no_deleg = WND4_NOT_SUPP_UPGRADE;
 		}

fs/nfsd/nfs4xdr.c

@@ -1067,7 +1067,7 @@ static __be32 nfsd4_decode_share_access(struct nfsd4_compoundargs *argp, u32 *sh
 		return nfs_ok;
 	if (!argp->minorversion)
 		return nfserr_bad_xdr;
-	switch (w & NFS4_SHARE_WANT_MASK) {
+	switch (w & NFS4_SHARE_WANT_TYPE_MASK) {
 	case OPEN4_SHARE_ACCESS_WANT_NO_PREFERENCE:
 	case OPEN4_SHARE_ACCESS_WANT_READ_DELEG:
 	case OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG:

include/uapi/linux/nfs4.h

@@ -58,21 +58,24 @@
 #define NFS4_SHARE_DENY_BOTH	0x0003
 
 /* nfs41 */
-#define NFS4_SHARE_WANT_MASK		0xFF00
+#define NFS4_SHARE_WANT_TYPE_MASK	0xFF00
 #define NFS4_SHARE_WANT_NO_PREFERENCE	0x0000
 #define NFS4_SHARE_WANT_READ_DELEG	0x0100
 #define NFS4_SHARE_WANT_WRITE_DELEG	0x0200
 #define NFS4_SHARE_WANT_ANY_DELEG	0x0300
 #define NFS4_SHARE_WANT_NO_DELEG	0x0400
 #define NFS4_SHARE_WANT_CANCEL		0x0500
 
-#define NFS4_SHARE_WHEN_MASK		0xF0000
+#define NFS4_SHARE_WHEN_MASK				0xF0000
 #define NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL	0x10000
 #define NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED		0x20000
 
+#define NFS4_SHARE_WANT_MOD_MASK			0xF00000
 #define NFS4_SHARE_WANT_DELEG_TIMESTAMPS		0x100000
 #define NFS4_SHARE_WANT_OPEN_XOR_DELEGATION		0x200000
 
+#define NFS4_SHARE_WANT_MASK	(NFS4_SHARE_WANT_TYPE_MASK | NFS4_SHARE_WANT_MOD_MASK)
+
 #define NFS4_CDFC4_FORE	0x1
 #define NFS4_CDFC4_BACK 0x2
 #define NFS4_CDFC4_BOTH 0x3