From a5e0f06c63440b07d43e678684d6190b2bed758a Mon Sep 17 00:00:00 2001
From: Evgeniy Polyakov <zbr@ioremap.net>
Date: Mon, 24 Sep 2012 22:57:38 +0400
Subject: [PATCH] Populate cache on READ command when DNET_IO_FLAGS_CACHE
 ioflag is set

---
 cache/cache.cpp     |  5 +----
 library/dnet.c      | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 library/elliptics.h |  2 +-
 3 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/cache/cache.cpp b/cache/cache.cpp
index f7d0c4f..fe4df6a 100644
--- a/cache/cache.cpp
+++ b/cache/cache.cpp
@@ -320,7 +320,7 @@ class cache_t {
 
 using namespace ioremap::cache;
 
-int dnet_cmd_cache_io(struct dnet_net_state *st, struct dnet_cmd *cmd, char *data)
+int dnet_cmd_cache_io(struct dnet_net_state *st, struct dnet_cmd *cmd, struct dnet_io_attr *io, char *data)
 {
 	struct dnet_node *n = st->n;
 	int err = -ENOTSUP;
@@ -331,11 +331,8 @@ int dnet_cmd_cache_io(struct dnet_net_state *st, struct dnet_cmd *cmd, char *dat
 	cache_t *cache = (cache_t *)n->cache;
 
 	try {
-		struct dnet_io_attr *io = (struct dnet_io_attr *)data;
 		boost::shared_ptr<raw_data_t> d;
 
-		data += sizeof(struct dnet_io_attr);
-
 		switch (cmd->cmd) {
 			case DNET_CMD_WRITE:
 				cache->write(io->id, io->start, data, io->size, !!(io->flags & DNET_IO_FLAGS_CACHE_REMOVE_FROM_DISK));
diff --git a/library/dnet.c b/library/dnet.c
index d4e6e93..7cd9501 100644
--- a/library/dnet.c
+++ b/library/dnet.c
@@ -630,7 +630,7 @@ int dnet_process_cmd_raw(struct dnet_net_state *st, struct dnet_cmd *cmd, void *
 				 * Always check cache when reading!
 				 */
 				if ((io->flags & DNET_IO_FLAGS_CACHE) || (cmd->cmd != DNET_CMD_WRITE)) {
-					err = dnet_cmd_cache_io(st, cmd, data);
+					err = dnet_cmd_cache_io(st, cmd, io, data + sizeof(struct dnet_io_attr));
 
 					if (io->flags & DNET_IO_FLAGS_CACHE_ONLY)
 						break;
@@ -846,6 +846,47 @@ err_out_exit:
 	return err;
 }
 
+static int dnet_populate_cache(struct dnet_node *n, struct dnet_cmd *cmd, struct dnet_io_attr *io,
+		void *data, int fd, size_t fd_offset, size_t size)
+{
+	void *orig_data = data;
+	ssize_t err;
+
+	if (!data && fd >= 0) {
+		ssize_t tmp_size = size;
+
+		if (size >= n->cache_size)
+			return -ENOMEM;
+
+		orig_data = data = malloc(size);
+		if (!data)
+			return -ENOMEM;
+
+		while (tmp_size > 0) {
+			err = pread(fd, data, tmp_size, fd_offset);
+			if (err <= 0) {
+				dnet_log_err(n, "%s: failed to populate cache: pread: offset: %zd, size: %zd",
+						dnet_dump_id(&cmd->id), fd_offset, size);
+				goto err_out_free;
+			}
+
+			data += err;
+			tmp_size -= err;
+			fd_offset += err;
+		}
+	}
+
+	cmd->cmd = DNET_CMD_WRITE;
+	err = dnet_cmd_cache_io(n->st, cmd, io, orig_data);
+	cmd->cmd = DNET_CMD_READ;
+
+err_out_free:
+	if (data != orig_data)
+		free(orig_data);
+
+	return err;
+}
+
 int dnet_send_read_data(void *state, struct dnet_cmd *cmd, struct dnet_io_attr *io, void *data,
 		int fd, uint64_t offset, int close_on_exit)
 {
@@ -890,6 +931,11 @@ int dnet_send_read_data(void *state, struct dnet_cmd *cmd, struct dnet_io_attr *
 			dnet_dump_id(&c->id), dnet_cmd_string(c->cmd),
 			(unsigned long long)io->offset,	(unsigned long long)io->size);
 
+	/* only populate data which has zero offset and from column 0 */
+	if ((io->flags & DNET_IO_FLAGS_CACHE) && !io->offset && (io->type == 0)) {
+		err = dnet_populate_cache(st->n, c, rio, data, fd, offset, io->size);
+	}
+
 	dnet_convert_cmd(c);
 	dnet_convert_io_attr(rio);
 
diff --git a/library/elliptics.h b/library/elliptics.h
index 97ef058..c2992ef 100644
--- a/library/elliptics.h
+++ b/library/elliptics.h
@@ -720,7 +720,7 @@ int dnet_cmd_exec_raw(struct dnet_net_state *st, struct dnet_cmd *cmd, struct sp
 
 int dnet_cache_init(struct dnet_node *n);
 void dnet_cache_cleanup(struct dnet_node *n);
-int dnet_cmd_cache_io(struct dnet_net_state *st, struct dnet_cmd *cmd, char *data);
+int dnet_cmd_cache_io(struct dnet_net_state *st, struct dnet_cmd *cmd, struct dnet_io_attr *io, char *data);
 
 int __attribute__((weak)) dnet_remove_local(struct dnet_node *n, struct dnet_id *id);
 
-- 
2.11.4.GIT