[SMB3] Send durable handle v2 contexts when use of persistent handles required

Version 2 of the patch. Thanks to Dan Carpenter and the smatch
tool for finding a problem in the first version of this patch.

CC: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <steve.french@primarydata.com>

fs/cifs/cifsglob.h

@@ -1018,6 +1018,7 @@ struct cifs_fid {
 	__u64 persistent_fid;	/* persist file id for smb2 */
 	__u64 volatile_fid;	/* volatile file id for smb2 */
 	__u8 lease_key[SMB2_LEASE_KEY_SIZE];	/* lease key for smb2 */
+	__u8 create_guid[16];
 #endif
 	struct cifs_pending_open *pending_open;
 	unsigned int epoch;

fs/cifs/smb2pdu.c

@@ -1151,13 +1151,130 @@ add_lease_context(struct TCP_Server_Info *server, struct kvec *iov,
 	return 0;
 }
 
+static struct create_durable_v2 *
+create_durable_v2_buf(struct cifs_fid *pfid)
+{
+	struct create_durable_v2 *buf;
+
+	buf = kzalloc(sizeof(struct create_durable_v2), GFP_KERNEL);
+	if (!buf)
+		return NULL;
+
+	buf->ccontext.DataOffset = cpu_to_le16(offsetof
+					(struct create_durable_v2, dcontext));
+	buf->ccontext.DataLength = cpu_to_le32(sizeof(struct durable_context_v2));
+	buf->ccontext.NameOffset = cpu_to_le16(offsetof
+				(struct create_durable_v2, Name));
+	buf->ccontext.NameLength = cpu_to_le16(4);
+
+	buf->dcontext.Timeout = 0; /* Should this be configurable by workload */
+	buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
+	get_random_bytes(buf->dcontext.CreateGuid, 16);
+	memcpy(pfid->create_guid, buf->dcontext.CreateGuid, 16);
+
+	/* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DH2Q" */
+	buf->Name[0] = 'D';
+	buf->Name[1] = 'H';
+	buf->Name[2] = '2';
+	buf->Name[3] = 'Q';
+	return buf;
+}
+
+static struct create_durable_handle_reconnect_v2 *
+create_reconnect_durable_v2_buf(struct cifs_fid *fid)
+{
+	struct create_durable_handle_reconnect_v2 *buf;
+
+	buf = kzalloc(sizeof(struct create_durable_handle_reconnect_v2),
+			GFP_KERNEL);
+	if (!buf)
+		return NULL;
+
+	buf->ccontext.DataOffset =
+		cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
+				     dcontext));
+	buf->ccontext.DataLength =
+		cpu_to_le32(sizeof(struct durable_reconnect_context_v2));
+	buf->ccontext.NameOffset =
+		cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
+			    Name));
+	buf->ccontext.NameLength = cpu_to_le16(4);
+
+	buf->dcontext.Fid.PersistentFileId = fid->persistent_fid;
+	buf->dcontext.Fid.VolatileFileId = fid->volatile_fid;
+	buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
+	memcpy(buf->dcontext.CreateGuid, fid->create_guid, 16);
+
+	/* SMB2_CREATE_DURABLE_HANDLE_RECONNECT_V2 is "DH2C" */
+	buf->Name[0] = 'D';
+	buf->Name[1] = 'H';
+	buf->Name[2] = '2';
+	buf->Name[3] = 'C';
+	return buf;
+}
+
 static int
-add_durable_context(struct kvec *iov, unsigned int *num_iovec,
+add_durable_v2_context(struct kvec *iov, unsigned int *num_iovec,
 		    struct cifs_open_parms *oparms)
 {
 	struct smb2_create_req *req = iov[0].iov_base;
 	unsigned int num = *num_iovec;
 
+	iov[num].iov_base = create_durable_v2_buf(oparms->fid);
+	if (iov[num].iov_base == NULL)
+		return -ENOMEM;
+	iov[num].iov_len = sizeof(struct create_durable_v2);
+	if (!req->CreateContextsOffset)
+		req->CreateContextsOffset =
+			cpu_to_le32(sizeof(struct smb2_create_req) - 4 +
+								iov[1].iov_len);
+	le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable_v2));
+	inc_rfc1001_len(&req->hdr, sizeof(struct create_durable_v2));
+	*num_iovec = num + 1;
+	return 0;
+}
+
+static int
+add_durable_reconnect_v2_context(struct kvec *iov, unsigned int *num_iovec,
+		    struct cifs_open_parms *oparms)
+{
+	struct smb2_create_req *req = iov[0].iov_base;
+	unsigned int num = *num_iovec;
+
+	/* indicate that we don't need to relock the file */
+	oparms->reconnect = false;
+
+	iov[num].iov_base = create_reconnect_durable_v2_buf(oparms->fid);
+	if (iov[num].iov_base == NULL)
+		return -ENOMEM;
+	iov[num].iov_len = sizeof(struct create_durable_handle_reconnect_v2);
+	if (!req->CreateContextsOffset)
+		req->CreateContextsOffset =
+			cpu_to_le32(sizeof(struct smb2_create_req) - 4 +
+								iov[1].iov_len);
+	le32_add_cpu(&req->CreateContextsLength,
+			sizeof(struct create_durable_handle_reconnect_v2));
+	inc_rfc1001_len(&req->hdr,
+			sizeof(struct create_durable_handle_reconnect_v2));
+	*num_iovec = num + 1;
+	return 0;
+}
+
+static int
+add_durable_context(struct kvec *iov, unsigned int *num_iovec,
+		    struct cifs_open_parms *oparms, bool use_persistent)
+{
+	struct smb2_create_req *req = iov[0].iov_base;
+	unsigned int num = *num_iovec;
+
+	if (use_persistent) {
+		if (oparms->reconnect)
+			return add_durable_reconnect_v2_context(iov, num_iovec,
+								oparms);
+		else
+			return add_durable_v2_context(iov, num_iovec, oparms);
+	}
+
 	if (oparms->reconnect) {
 		iov[num].iov_base = create_reconnect_durable_buf(oparms->fid);
 		/* indicate that we don't need to relock the file */
@@ -1275,7 +1392,9 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 			ccontext->Next =
 				cpu_to_le32(server->vals->create_lease_size);
 		}
-		rc = add_durable_context(iov, &num_iovecs, oparms);
+
+		rc = add_durable_context(iov, &num_iovecs, oparms,
+					tcon->use_persistent);
 		if (rc) {
 			cifs_small_buf_release(req);
 			kfree(copy_path);

fs/cifs/smb2pdu.h

@@ -590,6 +590,44 @@ struct create_durable {
 	} Data;
 } __packed;
 
+/* See MS-SMB2 2.2.13.2.11 */
+/* Flags */
+#define SMB2_DHANDLE_FLAG_PERSISTENT	0x00000002
+struct durable_context_v2 {
+	__le32 Timeout;
+	__le32 Flags;
+	__u64 Reserved;
+	__u8 CreateGuid[16];
+} __packed;
+
+struct create_durable_v2 {
+	struct create_context ccontext;
+	__u8   Name[8];
+	struct durable_context_v2 dcontext;
+} __packed;
+
+/* See MS-SMB2 2.2.13.2.12 */
+struct durable_reconnect_context_v2 {
+	struct {
+		__u64 PersistentFileId;
+		__u64 VolatileFileId;
+	} Fid;
+	__u8 CreateGuid[16];
+	__le32 Flags; /* see above DHANDLE_FLAG_PERSISTENT */
+} __packed;
+
+/* See MS-SMB2 2.2.14.2.12 */
+struct durable_reconnect_context_v2_rsp {
+	__le32 Timeout;
+	__le32 Flags; /* see above DHANDLE_FLAG_PERSISTENT */
+} __packed;
+
+struct create_durable_handle_reconnect_v2 {
+	struct create_context ccontext;
+	__u8   Name[8];
+	struct durable_reconnect_context_v2 dcontext;
+} __packed;
+
 #define COPY_CHUNK_RES_KEY_SIZE	24
 struct resume_key_req {
 	char ResumeKey[COPY_CHUNK_RES_KEY_SIZE];
@@ -643,6 +681,13 @@ struct fsctl_get_integrity_information_rsp {
 /* Integrity flags for above */
 #define FSCTL_INTEGRITY_FLAG_CHECKSUM_ENFORCEMENT_OFF	0x00000001
 
+/* See MS-SMB2 2.2.31.3 */
+struct network_resiliency_req {
+	__le32 Timeout;
+	__le32 Reserved;
+} __packed;
+/* There is no buffer for the response ie no struct network_resiliency_rsp */
+
 
 struct validate_negotiate_info_req {
 	__le32 Capabilities;

fs/cifs/smbfsctl.h

@@ -90,7 +90,7 @@
 #define FSCTL_SRV_ENUMERATE_SNAPSHOTS 0x00144064
 /* Retrieve an opaque file reference for server-side data movement ie copy */
 #define FSCTL_SRV_REQUEST_RESUME_KEY 0x00140078
-#define FSCTL_LMR_REQUEST_RESILIENCY 0x001401D4 /* BB add struct */
+#define FSCTL_LMR_REQUEST_RESILIENCY 0x001401D4
 #define FSCTL_LMR_GET_LINK_TRACK_INF 0x001400E8 /* BB add struct */
 #define FSCTL_LMR_SET_LINK_TRACK_INF 0x001400EC /* BB add struct */
 #define FSCTL_VALIDATE_NEGOTIATE_INFO 0x00140204