diff options
Diffstat (limited to 'drivers/staging/zcache/ramster/heartbeat.c')
-rw-r--r-- | drivers/staging/zcache/ramster/heartbeat.c | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/drivers/staging/zcache/ramster/heartbeat.c b/drivers/staging/zcache/ramster/heartbeat.c new file mode 100644 index 00000000000..75d3fe80b05 --- /dev/null +++ b/drivers/staging/zcache/ramster/heartbeat.c @@ -0,0 +1,462 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * Copyright (C) 2004, 2005, 2012 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/configfs.h> + +#include "heartbeat.h" +#include "tcp.h" +#include "nodemanager.h" + +#include "masklog.h" + +/* + * The first heartbeat pass had one global thread that would serialize all hb + * callback calls. This global serializing sem should only be removed once + * we've made sure that all callees can deal with being called concurrently + * from multiple hb region threads. + */ +static DECLARE_RWSEM(r2hb_callback_sem); + +/* + * multiple hb threads are watching multiple regions. A node is live + * whenever any of the threads sees activity from the node in its region. + */ +static DEFINE_SPINLOCK(r2hb_live_lock); +static unsigned long r2hb_live_node_bitmap[BITS_TO_LONGS(R2NM_MAX_NODES)]; + +static struct r2hb_callback { + struct list_head list; +} r2hb_callbacks[R2HB_NUM_CB]; + +enum r2hb_heartbeat_modes { + R2HB_HEARTBEAT_LOCAL = 0, + R2HB_HEARTBEAT_GLOBAL, + R2HB_HEARTBEAT_NUM_MODES, +}; + +char *r2hb_heartbeat_mode_desc[R2HB_HEARTBEAT_NUM_MODES] = { + "local", /* R2HB_HEARTBEAT_LOCAL */ + "global", /* R2HB_HEARTBEAT_GLOBAL */ +}; + +unsigned int r2hb_dead_threshold = R2HB_DEFAULT_DEAD_THRESHOLD; +unsigned int r2hb_heartbeat_mode = R2HB_HEARTBEAT_LOCAL; + +/* Only sets a new threshold if there are no active regions. + * + * No locking or otherwise interesting code is required for reading + * r2hb_dead_threshold as it can't change once regions are active and + * it's not interesting to anyone until then anyway. */ +static void r2hb_dead_threshold_set(unsigned int threshold) +{ + if (threshold > R2HB_MIN_DEAD_THRESHOLD) { + spin_lock(&r2hb_live_lock); + r2hb_dead_threshold = threshold; + spin_unlock(&r2hb_live_lock); + } +} + +static int r2hb_global_hearbeat_mode_set(unsigned int hb_mode) +{ + int ret = -1; + + if (hb_mode < R2HB_HEARTBEAT_NUM_MODES) { + spin_lock(&r2hb_live_lock); + r2hb_heartbeat_mode = hb_mode; + ret = 0; + spin_unlock(&r2hb_live_lock); + } + + return ret; +} + +void r2hb_exit(void) +{ +} + +int r2hb_init(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(r2hb_callbacks); i++) + INIT_LIST_HEAD(&r2hb_callbacks[i].list); + + memset(r2hb_live_node_bitmap, 0, sizeof(r2hb_live_node_bitmap)); + + return 0; +} + +/* if we're already in a callback then we're already serialized by the sem */ +static void r2hb_fill_node_map_from_callback(unsigned long *map, + unsigned bytes) +{ + BUG_ON(bytes < (BITS_TO_LONGS(R2NM_MAX_NODES) * sizeof(unsigned long))); + + memcpy(map, &r2hb_live_node_bitmap, bytes); +} + +/* + * get a map of all nodes that are heartbeating in any regions + */ +void r2hb_fill_node_map(unsigned long *map, unsigned bytes) +{ + /* callers want to serialize this map and callbacks so that they + * can trust that they don't miss nodes coming to the party */ + down_read(&r2hb_callback_sem); + spin_lock(&r2hb_live_lock); + r2hb_fill_node_map_from_callback(map, bytes); + spin_unlock(&r2hb_live_lock); + up_read(&r2hb_callback_sem); +} +EXPORT_SYMBOL_GPL(r2hb_fill_node_map); + +/* + * heartbeat configfs bits. The heartbeat set is a default set under + * the cluster set in nodemanager.c. + */ + +/* heartbeat set */ + +struct r2hb_hb_group { + struct config_group hs_group; + /* some stuff? */ +}; + +static struct r2hb_hb_group *to_r2hb_hb_group(struct config_group *group) +{ + return group ? + container_of(group, struct r2hb_hb_group, hs_group) + : NULL; +} + +static struct config_item r2hb_config_item; + +static struct config_item *r2hb_hb_group_make_item(struct config_group *group, + const char *name) +{ + int ret; + + if (strlen(name) > R2HB_MAX_REGION_NAME_LEN) { + ret = -ENAMETOOLONG; + goto free; + } + + config_item_put(&r2hb_config_item); + + return &r2hb_config_item; +free: + return ERR_PTR(ret); +} + +static void r2hb_hb_group_drop_item(struct config_group *group, + struct config_item *item) +{ + if (r2hb_global_heartbeat_active()) { + pr_notice("ramster: Heartbeat %s on region %s (%s)\n", + "stopped/aborted", config_item_name(item), + "no region"); + } + + config_item_put(item); +} + +struct r2hb_hb_group_attribute { + struct configfs_attribute attr; + ssize_t (*show)(struct r2hb_hb_group *, char *); + ssize_t (*store)(struct r2hb_hb_group *, const char *, size_t); +}; + +static ssize_t r2hb_hb_group_show(struct config_item *item, + struct configfs_attribute *attr, + char *page) +{ + struct r2hb_hb_group *reg = to_r2hb_hb_group(to_config_group(item)); + struct r2hb_hb_group_attribute *r2hb_hb_group_attr = + container_of(attr, struct r2hb_hb_group_attribute, attr); + ssize_t ret = 0; + + if (r2hb_hb_group_attr->show) + ret = r2hb_hb_group_attr->show(reg, page); + return ret; +} + +static ssize_t r2hb_hb_group_store(struct config_item *item, + struct configfs_attribute *attr, + const char *page, size_t count) +{ + struct r2hb_hb_group *reg = to_r2hb_hb_group(to_config_group(item)); + struct r2hb_hb_group_attribute *r2hb_hb_group_attr = + container_of(attr, struct r2hb_hb_group_attribute, attr); + ssize_t ret = -EINVAL; + + if (r2hb_hb_group_attr->store) + ret = r2hb_hb_group_attr->store(reg, page, count); + return ret; +} + +static ssize_t r2hb_hb_group_threshold_show(struct r2hb_hb_group *group, + char *page) +{ + return sprintf(page, "%u\n", r2hb_dead_threshold); +} + +static ssize_t r2hb_hb_group_threshold_store(struct r2hb_hb_group *group, + const char *page, + size_t count) +{ + unsigned long tmp; + char *p = (char *)page; + int err; + + err = kstrtoul(p, 10, &tmp); + if (err) + return err; + + /* this will validate ranges for us. */ + r2hb_dead_threshold_set((unsigned int) tmp); + + return count; +} + +static +ssize_t r2hb_hb_group_mode_show(struct r2hb_hb_group *group, + char *page) +{ + return sprintf(page, "%s\n", + r2hb_heartbeat_mode_desc[r2hb_heartbeat_mode]); +} + +static +ssize_t r2hb_hb_group_mode_store(struct r2hb_hb_group *group, + const char *page, size_t count) +{ + unsigned int i; + int ret; + size_t len; + + len = (page[count - 1] == '\n') ? count - 1 : count; + if (!len) + return -EINVAL; + + for (i = 0; i < R2HB_HEARTBEAT_NUM_MODES; ++i) { + if (strnicmp(page, r2hb_heartbeat_mode_desc[i], len)) + continue; + + ret = r2hb_global_hearbeat_mode_set(i); + if (!ret) + pr_notice("ramster: Heartbeat mode set to %s\n", + r2hb_heartbeat_mode_desc[i]); + return count; + } + + return -EINVAL; + +} + +static struct r2hb_hb_group_attribute r2hb_hb_group_attr_threshold = { + .attr = { .ca_owner = THIS_MODULE, + .ca_name = "dead_threshold", + .ca_mode = S_IRUGO | S_IWUSR }, + .show = r2hb_hb_group_threshold_show, + .store = r2hb_hb_group_threshold_store, +}; + +static struct r2hb_hb_group_attribute r2hb_hb_group_attr_mode = { + .attr = { .ca_owner = THIS_MODULE, + .ca_name = "mode", + .ca_mode = S_IRUGO | S_IWUSR }, + .show = r2hb_hb_group_mode_show, + .store = r2hb_hb_group_mode_store, +}; + +static struct configfs_attribute *r2hb_hb_group_attrs[] = { + &r2hb_hb_group_attr_threshold.attr, + &r2hb_hb_group_attr_mode.attr, + NULL, +}; + +static struct configfs_item_operations r2hb_hearbeat_group_item_ops = { + .show_attribute = r2hb_hb_group_show, + .store_attribute = r2hb_hb_group_store, +}; + +static struct configfs_group_operations r2hb_hb_group_group_ops = { + .make_item = r2hb_hb_group_make_item, + .drop_item = r2hb_hb_group_drop_item, +}; + +static struct config_item_type r2hb_hb_group_type = { + .ct_group_ops = &r2hb_hb_group_group_ops, + .ct_item_ops = &r2hb_hearbeat_group_item_ops, + .ct_attrs = r2hb_hb_group_attrs, + .ct_owner = THIS_MODULE, +}; + +/* this is just here to avoid touching group in heartbeat.h which the + * entire damn world #includes */ +struct config_group *r2hb_alloc_hb_set(void) +{ + struct r2hb_hb_group *hs = NULL; + struct config_group *ret = NULL; + + hs = kzalloc(sizeof(struct r2hb_hb_group), GFP_KERNEL); + if (hs == NULL) + goto out; + + config_group_init_type_name(&hs->hs_group, "heartbeat", + &r2hb_hb_group_type); + + ret = &hs->hs_group; +out: + if (ret == NULL) + kfree(hs); + return ret; +} + +void r2hb_free_hb_set(struct config_group *group) +{ + struct r2hb_hb_group *hs = to_r2hb_hb_group(group); + kfree(hs); +} + +/* hb callback registration and issuing */ + +static struct r2hb_callback *hbcall_from_type(enum r2hb_callback_type type) +{ + if (type == R2HB_NUM_CB) + return ERR_PTR(-EINVAL); + + return &r2hb_callbacks[type]; +} + +void r2hb_setup_callback(struct r2hb_callback_func *hc, + enum r2hb_callback_type type, + r2hb_cb_func *func, + void *data, + int priority) +{ + INIT_LIST_HEAD(&hc->hc_item); + hc->hc_func = func; + hc->hc_data = data; + hc->hc_priority = priority; + hc->hc_type = type; + hc->hc_magic = R2HB_CB_MAGIC; +} +EXPORT_SYMBOL_GPL(r2hb_setup_callback); + +int r2hb_register_callback(const char *region_uuid, + struct r2hb_callback_func *hc) +{ + struct r2hb_callback_func *tmp; + struct list_head *iter; + struct r2hb_callback *hbcall; + int ret; + + BUG_ON(hc->hc_magic != R2HB_CB_MAGIC); + BUG_ON(!list_empty(&hc->hc_item)); + + hbcall = hbcall_from_type(hc->hc_type); + if (IS_ERR(hbcall)) { + ret = PTR_ERR(hbcall); + goto out; + } + + down_write(&r2hb_callback_sem); + + list_for_each(iter, &hbcall->list) { + tmp = list_entry(iter, struct r2hb_callback_func, hc_item); + if (hc->hc_priority < tmp->hc_priority) { + list_add_tail(&hc->hc_item, iter); + break; + } + } + if (list_empty(&hc->hc_item)) + list_add_tail(&hc->hc_item, &hbcall->list); + + up_write(&r2hb_callback_sem); + ret = 0; +out: + mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n", + ret, __builtin_return_address(0), hc); + return ret; +} +EXPORT_SYMBOL_GPL(r2hb_register_callback); + +void r2hb_unregister_callback(const char *region_uuid, + struct r2hb_callback_func *hc) +{ + BUG_ON(hc->hc_magic != R2HB_CB_MAGIC); + + mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n", + __builtin_return_address(0), hc); + + /* XXX Can this happen _with_ a region reference? */ + if (list_empty(&hc->hc_item)) + return; + + down_write(&r2hb_callback_sem); + + list_del_init(&hc->hc_item); + + up_write(&r2hb_callback_sem); +} +EXPORT_SYMBOL_GPL(r2hb_unregister_callback); + +int r2hb_check_node_heartbeating_from_callback(u8 node_num) +{ + unsigned long testing_map[BITS_TO_LONGS(R2NM_MAX_NODES)]; + + r2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map)); + if (!test_bit(node_num, testing_map)) { + mlog(ML_HEARTBEAT, + "node (%u) does not have heartbeating enabled.\n", + node_num); + return 0; + } + + return 1; +} +EXPORT_SYMBOL_GPL(r2hb_check_node_heartbeating_from_callback); + +void r2hb_stop_all_regions(void) +{ +} +EXPORT_SYMBOL_GPL(r2hb_stop_all_regions); + +/* + * this is just a hack until we get the plumbing which flips file systems + * read only and drops the hb ref instead of killing the node dead. + */ +int r2hb_global_heartbeat_active(void) +{ + return (r2hb_heartbeat_mode == R2HB_HEARTBEAT_GLOBAL); +} +EXPORT_SYMBOL(r2hb_global_heartbeat_active); + +/* added for RAMster */ +void r2hb_manual_set_node_heartbeating(int node_num) +{ + if (node_num < R2NM_MAX_NODES) + set_bit(node_num, r2hb_live_node_bitmap); +} +EXPORT_SYMBOL(r2hb_manual_set_node_heartbeating); |