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Subject[PATCH 10/19] TuxOnIce: Storage manager support.
Date
Add support for a userspace storage manager. This can be used - for
example - to provide nbd support, establishing a connection when we
begin to hibernate or resume and reestablishing the connection after the
atomic restore at resume time.

Signed-off-by: Nigel Cunningham <nigel@tuxonice.net>
---
include/linux/netlink.h | 1 +
kernel/power/Makefile | 2 +-
kernel/power/tuxonice_storage.c | 282 +++++++++++++++++++++++++++++++++++++++
kernel/power/tuxonice_storage.h | 10 ++
4 files changed, 294 insertions(+), 1 deletions(-)
create mode 100644 kernel/power/tuxonice_storage.c
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 5ba398e..d597e15 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -24,6 +24,7 @@
/* leave room for NETLINK_DM (DM Events) */
#define NETLINK_SCSITRANSPORT 18 /* SCSI Transports */
#define NETLINK_ECRYPTFS 19
+#define NETLINK_TOI_USM 21 /* Userspace storage manager */

#define MAX_LINKS 32

diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 180b89a..9ad139e 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -11,7 +11,7 @@ tuxonice_core-objs := tuxonice_modules.o tuxonice_sysfs.o tuxonice_highlevel.o \
obj-$(CONFIG_TOI) += tuxonice_builtin.o

ifdef CONFIG_NET
-tuxonice_core-objs += tuxonice_netlink.o
+tuxonice_core-objs += tuxonice_storage.o tuxonice_netlink.o
endif

obj-$(CONFIG_TOI_CORE) += tuxonice_core.o
diff --git a/kernel/power/tuxonice_storage.c b/kernel/power/tuxonice_storage.c
new file mode 100644
index 0000000..5dafc95
--- /dev/null
+++ b/kernel/power/tuxonice_storage.c
@@ -0,0 +1,282 @@
+/*
+ * kernel/power/tuxonice_storage.c
+ *
+ * Copyright (C) 2005-2008 Nigel Cunningham (nigel at tuxonice net)
+ *
+ * This file is released under the GPLv2.
+ *
+ * Routines for talking to a userspace program that manages storage.
+ *
+ * The kernel side:
+ * - starts the userspace program;
+ * - sends messages telling it when to open and close the connection;
+ * - tells it when to quit;
+ *
+ * The user space side:
+ * - passes messages regarding status;
+ *
+ */
+
+#include <linux/suspend.h>
+#include <linux/freezer.h>
+
+#include "tuxonice_sysfs.h"
+#include "tuxonice_modules.h"
+#include "tuxonice_netlink.h"
+#include "tuxonice_storage.h"
+#include "tuxonice_ui.h"
+
+static struct user_helper_data usm_helper_data;
+static struct toi_module_ops usm_ops;
+static int message_received, usm_prepare_count;
+static int storage_manager_last_action, storage_manager_action;
+
+static int usm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+ int type;
+ int *data;
+
+ type = nlh->nlmsg_type;
+
+ /* A control message: ignore them */
+ if (type < NETLINK_MSG_BASE)
+ return 0;
+
+ /* Unknown message: reply with EINVAL */
+ if (type >= USM_MSG_MAX)
+ return -EINVAL;
+
+ /* All operations require privileges, even GET */
+ if (security_netlink_recv(skb, CAP_NET_ADMIN))
+ return -EPERM;
+
+ /* Only allow one task to receive NOFREEZE privileges */
+ if (type == NETLINK_MSG_NOFREEZE_ME && usm_helper_data.pid != -1)
+ return -EBUSY;
+
+ data = (int *) NLMSG_DATA(nlh);
+
+ switch (type) {
+ case USM_MSG_SUCCESS:
+ case USM_MSG_FAILED:
+ message_received = type;
+ complete(&usm_helper_data.wait_for_process);
+ break;
+ default:
+ printk(KERN_INFO "Storage manager doesn't recognise "
+ "message %d.\n", type);
+ }
+
+ return 1;
+}
+
+#ifdef CONFIG_NET
+static int activations;
+
+int toi_activate_storage(int force)
+{
+ int tries = 1;
+
+ if (usm_helper_data.pid == -1 || !usm_ops.enabled)
+ return 0;
+
+ message_received = 0;
+ activations++;
+
+ if (activations > 1 && !force)
+ return 0;
+
+ while ((!message_received || message_received == USM_MSG_FAILED) &&
+ tries < 2) {
+ toi_prepare_status(DONT_CLEAR_BAR, "Activate storage attempt "
+ "%d.\n", tries);
+
+ init_completion(&usm_helper_data.wait_for_process);
+
+ toi_send_netlink_message(&usm_helper_data,
+ USM_MSG_CONNECT,
+ NULL, 0);
+
+ /* Wait 2 seconds for the userspace process to make contact */
+ wait_for_completion_timeout(&usm_helper_data.wait_for_process,
+ 2*HZ);
+
+ tries++;
+ }
+
+ return 0;
+}
+
+int toi_deactivate_storage(int force)
+{
+ if (usm_helper_data.pid == -1 || !usm_ops.enabled)
+ return 0;
+
+ message_received = 0;
+ activations--;
+
+ if (activations && !force)
+ return 0;
+
+ init_completion(&usm_helper_data.wait_for_process);
+
+ toi_send_netlink_message(&usm_helper_data,
+ USM_MSG_DISCONNECT,
+ NULL, 0);
+
+ wait_for_completion_timeout(&usm_helper_data.wait_for_process, 2*HZ);
+
+ if (!message_received || message_received == USM_MSG_FAILED) {
+ printk(KERN_INFO "Returning failure disconnecting storage.\n");
+ return 1;
+ }
+
+ return 0;
+}
+#endif
+
+static void storage_manager_simulate(void)
+{
+ printk(KERN_INFO "--- Storage manager simulate ---\n");
+ toi_prepare_usm();
+ schedule();
+ printk(KERN_INFO "--- Activate storage 1 ---\n");
+ toi_activate_storage(1);
+ schedule();
+ printk(KERN_INFO "--- Deactivate storage 1 ---\n");
+ toi_deactivate_storage(1);
+ schedule();
+ printk(KERN_INFO "--- Cleanup usm ---\n");
+ toi_cleanup_usm();
+ schedule();
+ printk(KERN_INFO "--- Storage manager simulate ends ---\n");
+}
+
+static int usm_storage_needed(void)
+{
+ return strlen(usm_helper_data.program);
+}
+
+static int usm_save_config_info(char *buf)
+{
+ int len = strlen(usm_helper_data.program);
+ memcpy(buf, usm_helper_data.program, len);
+ return len;
+}
+
+static void usm_load_config_info(char *buf, int size)
+{
+ /* Don't load the saved path if one has already been set */
+ if (usm_helper_data.program[0])
+ return;
+
+ memcpy(usm_helper_data.program, buf, size);
+}
+
+static int usm_memory_needed(void)
+{
+ /* ball park figure of 32 pages */
+ return 32 * PAGE_SIZE;
+}
+
+/* toi_prepare_usm
+ */
+int toi_prepare_usm(void)
+{
+ usm_prepare_count++;
+
+ if (usm_prepare_count > 1 || !usm_ops.enabled)
+ return 0;
+
+ usm_helper_data.pid = -1;
+
+ if (!*usm_helper_data.program)
+ return 0;
+
+ toi_netlink_setup(&usm_helper_data);
+
+ if (usm_helper_data.pid == -1)
+ printk(KERN_INFO "TuxOnIce Storage Manager wanted, but couldn't"
+ " start it.\n");
+
+ toi_activate_storage(0);
+
+ return usm_helper_data.pid != -1;
+}
+
+void toi_cleanup_usm(void)
+{
+ usm_prepare_count--;
+
+ if (usm_helper_data.pid > -1 && !usm_prepare_count) {
+ toi_deactivate_storage(0);
+ toi_netlink_close(&usm_helper_data);
+ }
+}
+
+static void storage_manager_activate(void)
+{
+ if (storage_manager_action == storage_manager_last_action)
+ return;
+
+ if (storage_manager_action)
+ toi_prepare_usm();
+ else
+ toi_cleanup_usm();
+
+ storage_manager_last_action = storage_manager_action;
+}
+
+/*
+ * User interface specific /sys/power/tuxonice entries.
+ */
+
+static struct toi_sysfs_data sysfs_params[] = {
+ SYSFS_NONE("simulate_atomic_copy", storage_manager_simulate),
+ SYSFS_INT("enabled", SYSFS_RW, &usm_ops.enabled, 0, 1, 0, NULL),
+ SYSFS_STRING("program", SYSFS_RW, usm_helper_data.program, 254, 0,
+ NULL),
+ SYSFS_INT("activate_storage", SYSFS_RW , &storage_manager_action, 0, 1,
+ 0, storage_manager_activate)
+};
+
+static struct toi_module_ops usm_ops = {
+ .type = MISC_MODULE,
+ .name = "usm",
+ .directory = "storage_manager",
+ .module = THIS_MODULE,
+ .storage_needed = usm_storage_needed,
+ .save_config_info = usm_save_config_info,
+ .load_config_info = usm_load_config_info,
+ .memory_needed = usm_memory_needed,
+
+ .sysfs_data = sysfs_params,
+ .num_sysfs_entries = sizeof(sysfs_params) /
+ sizeof(struct toi_sysfs_data),
+};
+
+/* toi_usm_sysfs_init
+ * Description: Boot time initialisation for user interface.
+ */
+int toi_usm_init(void)
+{
+ usm_helper_data.nl = NULL;
+ usm_helper_data.program[0] = '\0';
+ usm_helper_data.pid = -1;
+ usm_helper_data.skb_size = 0;
+ usm_helper_data.pool_limit = 6;
+ usm_helper_data.netlink_id = NETLINK_TOI_USM;
+ usm_helper_data.name = "userspace storage manager";
+ usm_helper_data.rcv_msg = usm_user_rcv_msg;
+ usm_helper_data.interface_version = 2;
+ usm_helper_data.must_init = 0;
+ init_completion(&usm_helper_data.wait_for_process);
+
+ return toi_register_module(&usm_ops);
+}
+
+void toi_usm_exit(void)
+{
+ toi_netlink_close_complete(&usm_helper_data);
+ toi_unregister_module(&usm_ops);
+}
diff --git a/kernel/power/tuxonice_storage.h b/kernel/power/tuxonice_storage.h
index af48608..24f8e8a 100644
--- a/kernel/power/tuxonice_storage.h
+++ b/kernel/power/tuxonice_storage.h
@@ -6,6 +6,15 @@
* This file is released under the GPLv2.
*/

+#ifdef CONFIG_NET
+int toi_prepare_usm(void);
+void toi_cleanup_usm(void);
+
+int toi_activate_storage(int force);
+int toi_deactivate_storage(int force);
+extern int toi_usm_init(void);
+extern void toi_usm_exit(void);
+#else
static inline int toi_usm_init(void) { return 0; }
static inline void toi_usm_exit(void) { }

@@ -21,6 +30,7 @@ static inline int toi_deactivate_storage(int force)

static inline int toi_prepare_usm(void) { return 0; }
static inline void toi_cleanup_usm(void) { }
+#endif

enum {
USM_MSG_BASE = 0x10,
--
1.5.6.3


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