NFSv4: Add support for the FATTR4_OPEN_ARGUMENTS attribute

Query the server for the OPEN arguments that it supports so that
we can figure out which extensions we can use.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs4proc.c

@@ -3885,11 +3885,14 @@ static void nfs4_close_context(struct nfs_open_context *ctx, int is_sync)
 
 #define FATTR4_WORD1_NFS40_MASK (2*FATTR4_WORD1_MOUNTED_ON_FILEID - 1UL)
 #define FATTR4_WORD2_NFS41_MASK (2*FATTR4_WORD2_SUPPATTR_EXCLCREAT - 1UL)
-#define FATTR4_WORD2_NFS42_MASK (2*FATTR4_WORD2_TIME_DELEG_MODIFY - 1UL)
+#define FATTR4_WORD2_NFS42_MASK (2*FATTR4_WORD2_OPEN_ARGUMENTS - 1UL)
 
 static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle)
 {
-	u32 bitmask[3] = {}, minorversion = server->nfs_client->cl_minorversion;
+	u32 minorversion = server->nfs_client->cl_minorversion;
+	u32 bitmask[3] = {
+		[0] = FATTR4_WORD0_SUPPORTED_ATTRS,
+	};
 	struct nfs4_server_caps_arg args = {
 		.fhandle = fhandle,
 		.bitmask = bitmask,
@@ -3915,6 +3918,14 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
 
 	status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
 	if (status == 0) {
+		bitmask[0] = (FATTR4_WORD0_SUPPORTED_ATTRS |
+			      FATTR4_WORD0_FH_EXPIRE_TYPE |
+			      FATTR4_WORD0_LINK_SUPPORT |
+			      FATTR4_WORD0_SYMLINK_SUPPORT |
+			      FATTR4_WORD0_ACLSUPPORT |
+			      FATTR4_WORD0_CASE_INSENSITIVE |
+			      FATTR4_WORD0_CASE_PRESERVING) &
+			     res.attr_bitmask[0];
 		/* Sanity check the server answers */
 		switch (minorversion) {
 		case 0:
@@ -3923,9 +3934,14 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
 			break;
 		case 1:
 			res.attr_bitmask[2] &= FATTR4_WORD2_NFS41_MASK;
+			bitmask[2] = FATTR4_WORD2_SUPPATTR_EXCLCREAT &
+				     res.attr_bitmask[2];
 			break;
 		case 2:
 			res.attr_bitmask[2] &= FATTR4_WORD2_NFS42_MASK;
+			bitmask[2] = (FATTR4_WORD2_SUPPATTR_EXCLCREAT |
+				      FATTR4_WORD2_OPEN_ARGUMENTS) &
+				     res.attr_bitmask[2];
 		}
 		memcpy(server->attr_bitmask, res.attr_bitmask, sizeof(server->attr_bitmask));
 		server->caps &= ~(NFS_CAP_ACLS | NFS_CAP_HARDLINKS |

fs/nfs/nfs4xdr.c

@@ -4337,6 +4337,28 @@ static int decode_attr_xattrsupport(struct xdr_stream *xdr, uint32_t *bitmap,
 	return 0;
 }
 
+static int decode_attr_open_arguments(struct xdr_stream *xdr, uint32_t *bitmap,
+		struct nfs4_open_caps *res)
+{
+	memset(res, 0, sizeof(*res));
+	if (unlikely(bitmap[2] & (FATTR4_WORD2_OPEN_ARGUMENTS - 1U)))
+		return -EIO;
+	if (likely(bitmap[2] & FATTR4_WORD2_OPEN_ARGUMENTS)) {
+		if (decode_bitmap4(xdr, res->oa_share_access, ARRAY_SIZE(res->oa_share_access)) < 0)
+			return -EIO;
+		if (decode_bitmap4(xdr, res->oa_share_deny, ARRAY_SIZE(res->oa_share_deny)) < 0)
+			return -EIO;
+		if (decode_bitmap4(xdr, res->oa_share_access_want, ARRAY_SIZE(res->oa_share_access_want)) < 0)
+			return -EIO;
+		if (decode_bitmap4(xdr, res->oa_open_claim, ARRAY_SIZE(res->oa_open_claim)) < 0)
+			return -EIO;
+		if (decode_bitmap4(xdr, res->oa_createmode, ARRAY_SIZE(res->oa_createmode)) < 0)
+			return -EIO;
+		bitmap[2] &= ~FATTR4_WORD2_OPEN_ARGUMENTS;
+	}
+	return 0;
+}
+
 static int verify_attr_len(struct xdr_stream *xdr, unsigned int savep, uint32_t attrlen)
 {
 	unsigned int attrwords = XDR_QUADLEN(attrlen);
@@ -4511,6 +4533,8 @@ static int decode_server_caps(struct xdr_stream *xdr, struct nfs4_server_caps_re
 	if ((status = decode_attr_exclcreat_supported(xdr, bitmap,
 				res->exclcreat_bitmask)) != 0)
 		goto xdr_error;
+	if ((status = decode_attr_open_arguments(xdr, bitmap, &res->open_caps)) != 0)
+		goto xdr_error;
 	status = verify_attr_len(xdr, savep, attrlen);
 xdr_error:
 	dprintk("%s: xdr returned %d!\n", __func__, -status);

include/linux/nfs4.h

@@ -512,6 +512,7 @@ enum {
 enum {
 	FATTR4_TIME_DELEG_ACCESS	= 84,
 	FATTR4_TIME_DELEG_MODIFY	= 85,
+	FATTR4_OPEN_ARGUMENTS		= 86,
 };
 
 /*
@@ -595,6 +596,7 @@ enum {
 #define FATTR4_WORD2_XATTR_SUPPORT	BIT(FATTR4_XATTR_SUPPORT - 64)
 #define FATTR4_WORD2_TIME_DELEG_ACCESS	BIT(FATTR4_TIME_DELEG_ACCESS - 64)
 #define FATTR4_WORD2_TIME_DELEG_MODIFY	BIT(FATTR4_TIME_DELEG_MODIFY - 64)
+#define FATTR4_WORD2_OPEN_ARGUMENTS	BIT(FATTR4_OPEN_ARGUMENTS - 64)
 
 /* MDS threshold bitmap bits */
 #define THRESHOLD_RD                    (1UL << 0)

include/linux/nfs_xdr.h

@@ -1213,6 +1213,14 @@ struct nfs4_statfs_res {
 	struct nfs_fsstat	       *fsstat;
 };
 
+struct nfs4_open_caps {
+	u32				oa_share_access[1];
+	u32				oa_share_deny[1];
+	u32				oa_share_access_want[1];
+	u32				oa_open_claim[1];
+	u32				oa_createmode[1];
+};
+
 struct nfs4_server_caps_arg {
 	struct nfs4_sequence_args	seq_args;
 	struct nfs_fh		       *fhandle;
@@ -1229,6 +1237,7 @@ struct nfs4_server_caps_res {
 	u32				fh_expire_type;
 	u32				case_insensitive;
 	u32				case_preserving;
+	struct nfs4_open_caps		open_caps;
 };
 
 #define NFS4_PATHNAME_MAXCOMPONENTS 512