Introduce ocf_forward_write_zeros()

This is meant to be used in atomic mode to avoid allocating huge buffers
for zeroing data on drive.

Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>

inc/ocf_io.h

@@ -285,6 +285,20 @@ void ocf_forward_flush(ocf_volume_t volume, ocf_forward_token_t token);
 void ocf_forward_discard(ocf_volume_t volume, ocf_forward_token_t token,
 		uint64_t addr, uint64_t bytes);
 
+/**
+ * @brief Forward write_zeros to another subvolume
+ *
+ * Forwarding automatically increases forwarded io refcount, so at some
+ * point additional ocf_forward_end() needs to be called to balance it.
+ *
+ * @param[in] volume Volume to which IO is being submitted
+ * @param[in] token Token representing IO to be forwarded
+ * @param[in] addr Address to which IO is being submitted
+ * @param[in] bytes Length of the IO
+ */
+void ocf_forward_write_zeros(ocf_volume_t volume, ocf_forward_token_t token,
+		uint64_t addr, uint64_t bytes);
+
 /**
  * @brief Increment forwarded io refcount
  *

inc/ocf_volume.h

@@ -116,6 +116,19 @@ struct ocf_volume_ops {
 	void (*forward_discard)(ocf_volume_t volume, ocf_forward_token_t token,
 			uint64_t addr, uint64_t bytes);
 
+	/**
+	 * @brief Froward operation to write zeros to target address (including
+	 *        metadata extended LBAs in atomic mode)
+	 *
+	 * @param[in] volume Volume to which IO is being submitted
+	 * @param[in] token Token representing IO to be forwarded
+	 * @param[in] addr Address to which IO is being submitted
+	 * @param[in] bytes Length of the IO
+	 */
+	void (*forward_write_zeros)(ocf_volume_t volume,
+			ocf_forward_token_t token, uint64_t addr,
+			uint64_t bytes);
+
 	/**
 	 * @brief Volume initialization callback, called when volume object
 	 *        is being initialized

src/ocf_request.c

@@ -467,6 +467,18 @@ void ocf_req_forward_cache_discard(struct ocf_request *req, uint64_t addr,
 	ocf_volume_forward_discard(volume, token, addr, bytes);
 }
 
+void ocf_req_forward_cache_write_zeros(struct ocf_request *req, uint64_t addr,
+		uint64_t bytes)
+{
+	ocf_volume_t volume = ocf_cache_get_volume(req->cache);
+	ocf_forward_token_t token = ocf_req_to_cache_forward_token(req);
+
+	req->cache_error = 0;
+
+	ocf_req_forward_cache_get(req);
+	ocf_volume_forward_write_zeros(volume, token, addr, bytes);
+}
+
 void ocf_req_forward_core_io(struct ocf_request *req, int dir, uint64_t addr,
 		uint64_t bytes, uint64_t offset)
 {
@@ -544,6 +556,13 @@ void ocf_forward_discard(ocf_volume_t volume, ocf_forward_token_t token,
 	ocf_volume_forward_discard(volume, token, addr, bytes);
 }
 
+void ocf_forward_write_zeros(ocf_volume_t volume, ocf_forward_token_t token,
+		uint64_t addr, uint64_t bytes)
+{
+	_ocf_forward_get(token);
+	ocf_volume_forward_write_zeros(volume, token, addr, bytes);
+}
+
 void ocf_forward_end(ocf_forward_token_t token, int error)
 {
 	struct ocf_request *req = ocf_req_forward_token_to_req(token);

src/ocf_request.h

@@ -561,6 +561,9 @@ void ocf_req_forward_cache_flush(struct ocf_request *req);
 void ocf_req_forward_cache_discard(struct ocf_request *req, uint64_t addr,
 		uint64_t bytes);
 
+void ocf_req_forward_cache_write_zeros(struct ocf_request *req, uint64_t addr,
+		uint64_t bytes);
+
 void ocf_req_forward_core_io(struct ocf_request *req, int dir, uint64_t addr,
 		uint64_t bytes, uint64_t offset);
 

src/ocf_volume.c

@@ -370,6 +370,20 @@ void ocf_volume_forward_discard(ocf_volume_t volume, ocf_forward_token_t token,
 			addr, bytes);
 }
 
+void ocf_volume_forward_write_zeros(ocf_volume_t volume,
+		ocf_forward_token_t token, uint64_t addr, uint64_t bytes)
+{
+	ENV_BUG_ON(!volume->type->properties->ops.forward_write_zeros);
+
+	if (!volume->opened) {
+		ocf_forward_end(token, -OCF_ERR_IO);
+		return;
+	}
+
+	volume->type->properties->ops.forward_write_zeros(volume, token,
+			addr, bytes);
+}
+
 int ocf_volume_open(ocf_volume_t volume, void *volume_params)
 {
 	int ret;

src/ocf_volume_priv.h

@@ -55,6 +55,9 @@ void ocf_volume_forward_flush(ocf_volume_t volume, ocf_forward_token_t token);
 void ocf_volume_forward_discard(ocf_volume_t volume, ocf_forward_token_t token,
 		uint64_t addr, uint64_t bytes);
 
+void ocf_volume_forward_write_zeros(ocf_volume_t volume,
+		ocf_forward_token_t token, uint64_t addr, uint64_t bytes);
+
 static inline void ocf_volume_submit_metadata(struct ocf_io *io)
 {
 	ocf_volume_t volume = ocf_io_get_volume(io);

tests/functional/pyocf/types/volume.py

@@ -54,6 +54,7 @@ class VolumeOps(Structure):
     FORWARD_IO = CFUNCTYPE(None, c_void_p, c_uint64, c_int, c_uint64, c_uint64, c_uint64)
     FORWARD_FLUSH = CFUNCTYPE(None, c_void_p, c_uint64)
     FORWARD_DISCARD = CFUNCTYPE(None, c_void_p, c_uint64, c_uint64, c_uint64)
+    FORWARD_WRITE_ZEROS = CFUNCTYPE(None, c_void_p, c_uint64, c_uint64, c_uint64)
     ON_INIT = CFUNCTYPE(c_int, c_void_p)
     ON_DEINIT = CFUNCTYPE(None, c_void_p)
     OPEN = CFUNCTYPE(c_int, c_void_p, c_void_p)
@@ -70,6 +71,7 @@ class VolumeOps(Structure):
         ("_forward_io", FORWARD_IO),
         ("_forward_flush", FORWARD_FLUSH),
         ("_forward_discard", FORWARD_DISCARD),
+        ("_forward_write_zeros", FORWARD_WRITE_ZEROS),
         ("_on_init", ON_INIT),
         ("_on_deinit", ON_DEINIT),
         ("_open", OPEN),