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linux/fs/ocfs2/cluster/heartbeat.c
Sunil Mushran 87d3d3f393 ocfs2/hb: Expose the list of heartbeating nodes via debugfs 
This patch creates a debugfs file, o2hb/livesnodes, which exposes the
aggregate list of heartbeating node across all heartbeat regions.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-04-03 11:39:14 -07:00

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49 KiB
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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* Copyright (C) 2004, 2005 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/sched.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/file.h>
#include <linux/kthread.h>
#include <linux/configfs.h>
#include <linux/random.h>
#include <linux/crc32.h>
#include <linux/time.h>
#include <linux/debugfs.h>
#include "heartbeat.h"
#include "tcp.h"
#include "nodemanager.h"
#include "quorum.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(o2hb_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(o2hb_live_lock);
static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
static LIST_HEAD(o2hb_node_events);
static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
#define O2HB_DEBUG_DIR "o2hb"
#define O2HB_DEBUG_LIVENODES "livenodes"
static struct dentry *o2hb_debug_dir;
static struct dentry *o2hb_debug_livenodes;
static LIST_HEAD(o2hb_all_regions);
static struct o2hb_callback {
struct list_head list;
} o2hb_callbacks[O2HB_NUM_CB];
static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
#define O2HB_DEFAULT_BLOCK_BITS 9
unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
/* Only sets a new threshold if there are no active regions.
*
* No locking or otherwise interesting code is required for reading
* o2hb_dead_threshold as it can't change once regions are active and
* it's not interesting to anyone until then anyway. */
static void o2hb_dead_threshold_set(unsigned int threshold)
{
if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
spin_lock(&o2hb_live_lock);
if (list_empty(&o2hb_all_regions))
o2hb_dead_threshold = threshold;
spin_unlock(&o2hb_live_lock);
}
}
struct o2hb_node_event {
struct list_head hn_item;
enum o2hb_callback_type hn_event_type;
struct o2nm_node *hn_node;
int hn_node_num;
};
struct o2hb_disk_slot {
struct o2hb_disk_heartbeat_block *ds_raw_block;
u8 ds_node_num;
u64 ds_last_time;
u64 ds_last_generation;
u16 ds_equal_samples;
u16 ds_changed_samples;
struct list_head ds_live_item;
};
/* each thread owns a region.. when we're asked to tear down the region
* we ask the thread to stop, who cleans up the region */
struct o2hb_region {
struct config_item hr_item;
struct list_head hr_all_item;
unsigned hr_unclean_stop:1;
/* protected by the hr_callback_sem */
struct task_struct *hr_task;
unsigned int hr_blocks;
unsigned long long hr_start_block;
unsigned int hr_block_bits;
unsigned int hr_block_bytes;
unsigned int hr_slots_per_page;
unsigned int hr_num_pages;
struct page **hr_slot_data;
struct block_device *hr_bdev;
struct o2hb_disk_slot *hr_slots;
/* let the person setting up hb wait for it to return until it
* has reached a 'steady' state. This will be fixed when we have
* a more complete api that doesn't lead to this sort of fragility. */
atomic_t hr_steady_iterations;
char hr_dev_name[BDEVNAME_SIZE];
unsigned int hr_timeout_ms;
/* randomized as the region goes up and down so that a node
* recognizes a node going up and down in one iteration */
u64 hr_generation;
struct delayed_work hr_write_timeout_work;
unsigned long hr_last_timeout_start;
/* Used during o2hb_check_slot to hold a copy of the block
* being checked because we temporarily have to zero out the
* crc field. */
struct o2hb_disk_heartbeat_block *hr_tmp_block;
};
struct o2hb_bio_wait_ctxt {
atomic_t wc_num_reqs;
struct completion wc_io_complete;
int wc_error;
};
static void o2hb_write_timeout(struct work_struct *work)
{
struct o2hb_region *reg =
container_of(work, struct o2hb_region,
hr_write_timeout_work.work);
mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
"milliseconds\n", reg->hr_dev_name,
jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
o2quo_disk_timeout();
}
static void o2hb_arm_write_timeout(struct o2hb_region *reg)
{
mlog(0, "Queue write timeout for %u ms\n", O2HB_MAX_WRITE_TIMEOUT_MS);
cancel_delayed_work(&reg->hr_write_timeout_work);
reg->hr_last_timeout_start = jiffies;
schedule_delayed_work(&reg->hr_write_timeout_work,
msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
}
static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
{
cancel_delayed_work(&reg->hr_write_timeout_work);
flush_scheduled_work();
}
static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
{
atomic_set(&wc->wc_num_reqs, 1);
init_completion(&wc->wc_io_complete);
wc->wc_error = 0;
}
/* Used in error paths too */
static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
unsigned int num)
{
/* sadly atomic_sub_and_test() isn't available on all platforms. The
* good news is that the fast path only completes one at a time */
while(num--) {
if (atomic_dec_and_test(&wc->wc_num_reqs)) {
BUG_ON(num > 0);
complete(&wc->wc_io_complete);
}
}
}
static void o2hb_wait_on_io(struct o2hb_region *reg,
struct o2hb_bio_wait_ctxt *wc)
{
struct address_space *mapping = reg->hr_bdev->bd_inode->i_mapping;
blk_run_address_space(mapping);
o2hb_bio_wait_dec(wc, 1);
wait_for_completion(&wc->wc_io_complete);
}
static void o2hb_bio_end_io(struct bio *bio,
int error)
{
struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
if (error) {
mlog(ML_ERROR, "IO Error %d\n", error);
wc->wc_error = error;
}
o2hb_bio_wait_dec(wc, 1);
bio_put(bio);
}
/* Setup a Bio to cover I/O against num_slots slots starting at
* start_slot. */
static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
struct o2hb_bio_wait_ctxt *wc,
unsigned int *current_slot,
unsigned int max_slots)
{
int len, current_page;
unsigned int vec_len, vec_start;
unsigned int bits = reg->hr_block_bits;
unsigned int spp = reg->hr_slots_per_page;
unsigned int cs = *current_slot;
struct bio *bio;
struct page *page;
/* Testing has shown this allocation to take long enough under
* GFP_KERNEL that the local node can get fenced. It would be
* nicest if we could pre-allocate these bios and avoid this
* all together. */
bio = bio_alloc(GFP_ATOMIC, 16);
if (!bio) {
mlog(ML_ERROR, "Could not alloc slots BIO!\n");
bio = ERR_PTR(-ENOMEM);
goto bail;
}
/* Must put everything in 512 byte sectors for the bio... */
bio->bi_sector = (reg->hr_start_block + cs) << (bits - 9);
bio->bi_bdev = reg->hr_bdev;
bio->bi_private = wc;
bio->bi_end_io = o2hb_bio_end_io;
vec_start = (cs << bits) % PAGE_CACHE_SIZE;
while(cs < max_slots) {
current_page = cs / spp;
page = reg->hr_slot_data[current_page];
vec_len = min(PAGE_CACHE_SIZE - vec_start,
(max_slots-cs) * (PAGE_CACHE_SIZE/spp) );
mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
current_page, vec_len, vec_start);
len = bio_add_page(bio, page, vec_len, vec_start);
if (len != vec_len) break;
cs += vec_len / (PAGE_CACHE_SIZE/spp);
vec_start = 0;
}
bail:
*current_slot = cs;
return bio;
}
static int o2hb_read_slots(struct o2hb_region *reg,
unsigned int max_slots)
{
unsigned int current_slot=0;
int status;
struct o2hb_bio_wait_ctxt wc;
struct bio *bio;
o2hb_bio_wait_init(&wc);
while(current_slot < max_slots) {
bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
if (IS_ERR(bio)) {
status = PTR_ERR(bio);
mlog_errno(status);
goto bail_and_wait;
}
atomic_inc(&wc.wc_num_reqs);
submit_bio(READ, bio);
}
status = 0;
bail_and_wait:
o2hb_wait_on_io(reg, &wc);
if (wc.wc_error && !status)
status = wc.wc_error;
return status;
}
static int o2hb_issue_node_write(struct o2hb_region *reg,
struct o2hb_bio_wait_ctxt *write_wc)
{
int status;
unsigned int slot;
struct bio *bio;
o2hb_bio_wait_init(write_wc);
slot = o2nm_this_node();
bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
if (IS_ERR(bio)) {
status = PTR_ERR(bio);
mlog_errno(status);
goto bail;
}
atomic_inc(&write_wc->wc_num_reqs);
submit_bio(WRITE, bio);
status = 0;
bail:
return status;
}
static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
struct o2hb_disk_heartbeat_block *hb_block)
{
__le32 old_cksum;
u32 ret;
/* We want to compute the block crc with a 0 value in the
* hb_cksum field. Save it off here and replace after the
* crc. */
old_cksum = hb_block->hb_cksum;
hb_block->hb_cksum = 0;
ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
hb_block->hb_cksum = old_cksum;
return ret;
}
static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
{
mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
"cksum = 0x%x, generation 0x%llx\n",
(long long)le64_to_cpu(hb_block->hb_seq),
hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
(long long)le64_to_cpu(hb_block->hb_generation));
}
static int o2hb_verify_crc(struct o2hb_region *reg,
struct o2hb_disk_heartbeat_block *hb_block)
{
u32 read, computed;
read = le32_to_cpu(hb_block->hb_cksum);
computed = o2hb_compute_block_crc_le(reg, hb_block);
return read == computed;
}
/* We want to make sure that nobody is heartbeating on top of us --
* this will help detect an invalid configuration. */
static int o2hb_check_last_timestamp(struct o2hb_region *reg)
{
int node_num, ret;
struct o2hb_disk_slot *slot;
struct o2hb_disk_heartbeat_block *hb_block;
node_num = o2nm_this_node();
ret = 1;
slot = &reg->hr_slots[node_num];
/* Don't check on our 1st timestamp */
if (slot->ds_last_time) {
hb_block = slot->ds_raw_block;
if (le64_to_cpu(hb_block->hb_seq) != slot->ds_last_time)
ret = 0;
}
return ret;
}
static inline void o2hb_prepare_block(struct o2hb_region *reg,
u64 generation)
{
int node_num;
u64 cputime;
struct o2hb_disk_slot *slot;
struct o2hb_disk_heartbeat_block *hb_block;
node_num = o2nm_this_node();
slot = &reg->hr_slots[node_num];
hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
memset(hb_block, 0, reg->hr_block_bytes);
/* TODO: time stuff */
cputime = CURRENT_TIME.tv_sec;
if (!cputime)
cputime = 1;
hb_block->hb_seq = cpu_to_le64(cputime);
hb_block->hb_node = node_num;
hb_block->hb_generation = cpu_to_le64(generation);
hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
/* This step must always happen last! */
hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
hb_block));
mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
(long long)generation,
le32_to_cpu(hb_block->hb_cksum));
}
static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
struct o2nm_node *node,
int idx)
{
struct list_head *iter;
struct o2hb_callback_func *f;
list_for_each(iter, &hbcall->list) {
f = list_entry(iter, struct o2hb_callback_func, hc_item);
mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
(f->hc_func)(node, idx, f->hc_data);
}
}
/* Will run the list in order until we process the passed event */
static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
{
int empty;
struct o2hb_callback *hbcall;
struct o2hb_node_event *event;
spin_lock(&o2hb_live_lock);
empty = list_empty(&queued_event->hn_item);
spin_unlock(&o2hb_live_lock);
if (empty)
return;
/* Holding callback sem assures we don't alter the callback
* lists when doing this, and serializes ourselves with other
* processes wanting callbacks. */
down_write(&o2hb_callback_sem);
spin_lock(&o2hb_live_lock);
while (!list_empty(&o2hb_node_events)
&& !list_empty(&queued_event->hn_item)) {
event = list_entry(o2hb_node_events.next,
struct o2hb_node_event,
hn_item);
list_del_init(&event->hn_item);
spin_unlock(&o2hb_live_lock);
mlog(ML_HEARTBEAT, "Node %s event for %d\n",
event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
event->hn_node_num);
hbcall = hbcall_from_type(event->hn_event_type);
/* We should *never* have gotten on to the list with a
* bad type... This isn't something that we should try
* to recover from. */
BUG_ON(IS_ERR(hbcall));
o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
spin_lock(&o2hb_live_lock);
}
spin_unlock(&o2hb_live_lock);
up_write(&o2hb_callback_sem);
}
static void o2hb_queue_node_event(struct o2hb_node_event *event,
enum o2hb_callback_type type,
struct o2nm_node *node,
int node_num)
{
assert_spin_locked(&o2hb_live_lock);
event->hn_event_type = type;
event->hn_node = node;
event->hn_node_num = node_num;
mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
list_add_tail(&event->hn_item, &o2hb_node_events);
}
static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
{
struct o2hb_node_event event =
{ .hn_item = LIST_HEAD_INIT(event.hn_item), };
struct o2nm_node *node;
node = o2nm_get_node_by_num(slot->ds_node_num);
if (!node)
return;
spin_lock(&o2hb_live_lock);
if (!list_empty(&slot->ds_live_item)) {
mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
slot->ds_node_num);
list_del_init(&slot->ds_live_item);
if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
slot->ds_node_num);
}
}
spin_unlock(&o2hb_live_lock);
o2hb_run_event_list(&event);
o2nm_node_put(node);
}
static int o2hb_check_slot(struct o2hb_region *reg,
struct o2hb_disk_slot *slot)
{
int changed = 0, gen_changed = 0;
struct o2hb_node_event event =
{ .hn_item = LIST_HEAD_INIT(event.hn_item), };
struct o2nm_node *node;
struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
u64 cputime;
unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
unsigned int slot_dead_ms;
memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
/* Is this correct? Do we assume that the node doesn't exist
* if we're not configured for him? */
node = o2nm_get_node_by_num(slot->ds_node_num);
if (!node)
return 0;
if (!o2hb_verify_crc(reg, hb_block)) {
/* all paths from here will drop o2hb_live_lock for
* us. */
spin_lock(&o2hb_live_lock);
/* Don't print an error on the console in this case -
* a freshly formatted heartbeat area will not have a
* crc set on it. */
if (list_empty(&slot->ds_live_item))
goto out;
/* The node is live but pushed out a bad crc. We
* consider it a transient miss but don't populate any
* other values as they may be junk. */
mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
slot->ds_node_num, reg->hr_dev_name);
o2hb_dump_slot(hb_block);
slot->ds_equal_samples++;
goto fire_callbacks;
}
/* we don't care if these wrap.. the state transitions below
* clear at the right places */
cputime = le64_to_cpu(hb_block->hb_seq);
if (slot->ds_last_time != cputime)
slot->ds_changed_samples++;
else
slot->ds_equal_samples++;
slot->ds_last_time = cputime;
/* The node changed heartbeat generations. We assume this to
* mean it dropped off but came back before we timed out. We
* want to consider it down for the time being but don't want
* to lose any changed_samples state we might build up to
* considering it live again. */
if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
gen_changed = 1;
slot->ds_equal_samples = 0;
mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
"to 0x%llx)\n", slot->ds_node_num,
(long long)slot->ds_last_generation,
(long long)le64_to_cpu(hb_block->hb_generation));
}
slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
"seq %llu last %llu changed %u equal %u\n",
slot->ds_node_num, (long long)slot->ds_last_generation,
le32_to_cpu(hb_block->hb_cksum),
(unsigned long long)le64_to_cpu(hb_block->hb_seq),
(unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
slot->ds_equal_samples);
spin_lock(&o2hb_live_lock);
fire_callbacks:
/* dead nodes only come to life after some number of
* changes at any time during their dead time */
if (list_empty(&slot->ds_live_item) &&
slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
slot->ds_node_num, (long long)slot->ds_last_generation);
/* first on the list generates a callback */
if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
slot->ds_node_num);
changed = 1;
}
list_add_tail(&slot->ds_live_item,
&o2hb_live_slots[slot->ds_node_num]);
slot->ds_equal_samples = 0;
/* We want to be sure that all nodes agree on the
* number of milliseconds before a node will be
* considered dead. The self-fencing timeout is
* computed from this value, and a discrepancy might
* result in heartbeat calling a node dead when it
* hasn't self-fenced yet. */
slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
if (slot_dead_ms && slot_dead_ms != dead_ms) {
/* TODO: Perhaps we can fail the region here. */
mlog(ML_ERROR, "Node %d on device %s has a dead count "
"of %u ms, but our count is %u ms.\n"
"Please double check your configuration values "
"for 'O2CB_HEARTBEAT_THRESHOLD'\n",
slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
dead_ms);
}
goto out;
}
/* if the list is dead, we're done.. */
if (list_empty(&slot->ds_live_item))
goto out;
/* live nodes only go dead after enough consequtive missed
* samples.. reset the missed counter whenever we see
* activity */
if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
mlog(ML_HEARTBEAT, "Node %d left my region\n",
slot->ds_node_num);
/* last off the live_slot generates a callback */
list_del_init(&slot->ds_live_item);
if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
slot->ds_node_num);
changed = 1;
}
/* We don't clear this because the node is still
* actually writing new blocks. */
if (!gen_changed)
slot->ds_changed_samples = 0;
goto out;
}
if (slot->ds_changed_samples) {
slot->ds_changed_samples = 0;
slot->ds_equal_samples = 0;
}
out:
spin_unlock(&o2hb_live_lock);
o2hb_run_event_list(&event);
o2nm_node_put(node);
return changed;
}
/* This could be faster if we just implmented a find_last_bit, but I
* don't think the circumstances warrant it. */
static int o2hb_highest_node(unsigned long *nodes,
int numbits)
{
int highest, node;
highest = numbits;
node = -1;
while ((node = find_next_bit(nodes, numbits, node + 1)) != -1) {
if (node >= numbits)
break;
highest = node;
}
return highest;
}
static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
{
int i, ret, highest_node, change = 0;
unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
struct o2hb_bio_wait_ctxt write_wc;
ret = o2nm_configured_node_map(configured_nodes,
sizeof(configured_nodes));
if (ret) {
mlog_errno(ret);
return ret;
}
highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
if (highest_node >= O2NM_MAX_NODES) {
mlog(ML_NOTICE, "ocfs2_heartbeat: no configured nodes found!\n");
return -EINVAL;
}
/* No sense in reading the slots of nodes that don't exist
* yet. Of course, if the node definitions have holes in them
* then we're reading an empty slot anyway... Consider this
* best-effort. */
ret = o2hb_read_slots(reg, highest_node + 1);
if (ret < 0) {
mlog_errno(ret);
return ret;
}
/* With an up to date view of the slots, we can check that no
* other node has been improperly configured to heartbeat in
* our slot. */
if (!o2hb_check_last_timestamp(reg))
mlog(ML_ERROR, "Device \"%s\": another node is heartbeating "
"in our slot!\n", reg->hr_dev_name);
/* fill in the proper info for our next heartbeat */
o2hb_prepare_block(reg, reg->hr_generation);
/* And fire off the write. Note that we don't wait on this I/O
* until later. */
ret = o2hb_issue_node_write(reg, &write_wc);
if (ret < 0) {
mlog_errno(ret);
return ret;
}
i = -1;
while((i = find_next_bit(configured_nodes, O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
}
/*
* We have to be sure we've advertised ourselves on disk
* before we can go to steady state. This ensures that
* people we find in our steady state have seen us.
*/
o2hb_wait_on_io(reg, &write_wc);
if (write_wc.wc_error) {
/* Do not re-arm the write timeout on I/O error - we
* can't be sure that the new block ever made it to
* disk */
mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
write_wc.wc_error, reg->hr_dev_name);
return write_wc.wc_error;
}
o2hb_arm_write_timeout(reg);
/* let the person who launched us know when things are steady */
if (!change && (atomic_read(&reg->hr_steady_iterations) != 0)) {
if (atomic_dec_and_test(&reg->hr_steady_iterations))
wake_up(&o2hb_steady_queue);
}
return 0;
}
/* Subtract b from a, storing the result in a. a *must* have a larger
* value than b. */
static void o2hb_tv_subtract(struct timeval *a,
struct timeval *b)
{
/* just return 0 when a is after b */
if (a->tv_sec < b->tv_sec ||
(a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) {
a->tv_sec = 0;
a->tv_usec = 0;
return;
}
a->tv_sec -= b->tv_sec;
a->tv_usec -= b->tv_usec;
while ( a->tv_usec < 0 ) {
a->tv_sec--;
a->tv_usec += 1000000;
}
}
static unsigned int o2hb_elapsed_msecs(struct timeval *start,
struct timeval *end)
{
struct timeval res = *end;
o2hb_tv_subtract(&res, start);
return res.tv_sec * 1000 + res.tv_usec / 1000;
}
/*
* we ride the region ref that the region dir holds. before the region
* dir is removed and drops it ref it will wait to tear down this
* thread.
*/
static int o2hb_thread(void *data)
{
int i, ret;
struct o2hb_region *reg = data;
struct o2hb_bio_wait_ctxt write_wc;
struct timeval before_hb, after_hb;
unsigned int elapsed_msec;
mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
set_user_nice(current, -20);
while (!kthread_should_stop() && !reg->hr_unclean_stop) {
/* We track the time spent inside
* o2hb_do_disk_heartbeat so that we avoid more than
* hr_timeout_ms between disk writes. On busy systems
* this should result in a heartbeat which is less
* likely to time itself out. */
do_gettimeofday(&before_hb);
i = 0;
do {
ret = o2hb_do_disk_heartbeat(reg);
} while (ret && ++i < 2);
do_gettimeofday(&after_hb);
elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb);
mlog(0, "start = %lu.%lu, end = %lu.%lu, msec = %u\n",
before_hb.tv_sec, (unsigned long) before_hb.tv_usec,
after_hb.tv_sec, (unsigned long) after_hb.tv_usec,
elapsed_msec);
if (elapsed_msec < reg->hr_timeout_ms) {
/* the kthread api has blocked signals for us so no
* need to record the return value. */
msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
}
}
o2hb_disarm_write_timeout(reg);
/* unclean stop is only used in very bad situation */
for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
o2hb_shutdown_slot(&reg->hr_slots[i]);
/* Explicit down notification - avoid forcing the other nodes
* to timeout on this region when we could just as easily
* write a clear generation - thus indicating to them that
* this node has left this region.
*
* XXX: Should we skip this on unclean_stop? */
o2hb_prepare_block(reg, 0);
ret = o2hb_issue_node_write(reg, &write_wc);
if (ret == 0) {
o2hb_wait_on_io(reg, &write_wc);
} else {
mlog_errno(ret);
}
mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread exiting\n");
return 0;
}
#ifdef CONFIG_DEBUG_FS
static int o2hb_debug_open(struct inode *inode, struct file *file)
{
unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
char *buf = NULL;
int i = -1;
int out = 0;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
goto bail;
o2hb_fill_node_map(map, sizeof(map));
while ((i = find_next_bit(map, O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES)
out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
out += snprintf(buf + out, PAGE_SIZE - out, "\n");
i_size_write(inode, out);
file->private_data = buf;
return 0;
bail:
return -ENOMEM;
}
static int o2hb_debug_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
}
static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
size_t nbytes, loff_t *ppos)
{
return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
i_size_read(file->f_mapping->host));
}
#else
static int o2hb_debug_open(struct inode *inode, struct file *file)
{
return 0;
}
static int o2hb_debug_release(struct inode *inode, struct file *file)
{
return 0;
}
static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
size_t nbytes, loff_t *ppos)
{
return 0;
}
#endif /* CONFIG_DEBUG_FS */
static struct file_operations o2hb_debug_fops = {
.open = o2hb_debug_open,
.release = o2hb_debug_release,
.read = o2hb_debug_read,
.llseek = generic_file_llseek,
};
void o2hb_exit(void)
{
if (o2hb_debug_livenodes)
debugfs_remove(o2hb_debug_livenodes);
if (o2hb_debug_dir)
debugfs_remove(o2hb_debug_dir);
}
int o2hb_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
INIT_LIST_HEAD(&o2hb_callbacks[i].list);
for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
INIT_LIST_HEAD(&o2hb_live_slots[i]);
INIT_LIST_HEAD(&o2hb_node_events);
memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
if (!o2hb_debug_dir) {
mlog_errno(-ENOMEM);
return -ENOMEM;
}
o2hb_debug_livenodes = debugfs_create_file(O2HB_DEBUG_LIVENODES,
S_IFREG|S_IRUSR,
o2hb_debug_dir, NULL,
&o2hb_debug_fops);
if (!o2hb_debug_livenodes) {
mlog_errno(-ENOMEM);
debugfs_remove(o2hb_debug_dir);
return -ENOMEM;
}
return 0;
}
/* if we're already in a callback then we're already serialized by the sem */
static void o2hb_fill_node_map_from_callback(unsigned long *map,
unsigned bytes)
{
BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
memcpy(map, &o2hb_live_node_bitmap, bytes);
}
/*
* get a map of all nodes that are heartbeating in any regions
*/
void o2hb_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(&o2hb_callback_sem);
spin_lock(&o2hb_live_lock);
o2hb_fill_node_map_from_callback(map, bytes);
spin_unlock(&o2hb_live_lock);
up_read(&o2hb_callback_sem);
}
EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
/*
* heartbeat configfs bits. The heartbeat set is a default set under
* the cluster set in nodemanager.c.
*/
static struct o2hb_region *to_o2hb_region(struct config_item *item)
{
return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
}
/* drop_item only drops its ref after killing the thread, nothing should
* be using the region anymore. this has to clean up any state that
* attributes might have built up. */
static void o2hb_region_release(struct config_item *item)
{
int i;
struct page *page;
struct o2hb_region *reg = to_o2hb_region(item);
if (reg->hr_tmp_block)
kfree(reg->hr_tmp_block);
if (reg->hr_slot_data) {
for (i = 0; i < reg->hr_num_pages; i++) {
page = reg->hr_slot_data[i];
if (page)
__free_page(page);
}
kfree(reg->hr_slot_data);
}
if (reg->hr_bdev)
blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
if (reg->hr_slots)
kfree(reg->hr_slots);
spin_lock(&o2hb_live_lock);
list_del(&reg->hr_all_item);
spin_unlock(&o2hb_live_lock);
kfree(reg);
}
static int o2hb_read_block_input(struct o2hb_region *reg,
const char *page,
size_t count,
unsigned long *ret_bytes,
unsigned int *ret_bits)
{
unsigned long bytes;
char *p = (char *)page;
bytes = simple_strtoul(p, &p, 0);
if (!p || (*p && (*p != '\n')))
return -EINVAL;
/* Heartbeat and fs min / max block sizes are the same. */
if (bytes > 4096 || bytes < 512)
return -ERANGE;
if (hweight16(bytes) != 1)
return -EINVAL;
if (ret_bytes)
*ret_bytes = bytes;
if (ret_bits)
*ret_bits = ffs(bytes) - 1;
return 0;
}
static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
char *page)
{
return sprintf(page, "%u\n", reg->hr_block_bytes);
}
static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
const char *page,
size_t count)
{
int status;
unsigned long block_bytes;
unsigned int block_bits;
if (reg->hr_bdev)
return -EINVAL;
status = o2hb_read_block_input(reg, page, count,
&block_bytes, &block_bits);
if (status)
return status;
reg->hr_block_bytes = (unsigned int)block_bytes;
reg->hr_block_bits = block_bits;
return count;
}
static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
char *page)
{
return sprintf(page, "%llu\n", reg->hr_start_block);
}
static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
const char *page,
size_t count)
{
unsigned long long tmp;
char *p = (char *)page;
if (reg->hr_bdev)
return -EINVAL;
tmp = simple_strtoull(p, &p, 0);
if (!p || (*p && (*p != '\n')))
return -EINVAL;
reg->hr_start_block = tmp;
return count;
}
static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
char *page)
{
return sprintf(page, "%d\n", reg->hr_blocks);
}
static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
const char *page,
size_t count)
{
unsigned long tmp;
char *p = (char *)page;
if (reg->hr_bdev)
return -EINVAL;
tmp = simple_strtoul(p, &p, 0);
if (!p || (*p && (*p != '\n')))
return -EINVAL;
if (tmp > O2NM_MAX_NODES || tmp == 0)
return -ERANGE;
reg->hr_blocks = (unsigned int)tmp;
return count;
}
static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
char *page)
{
unsigned int ret = 0;
if (reg->hr_bdev)
ret = sprintf(page, "%s\n", reg->hr_dev_name);
return ret;
}
static void o2hb_init_region_params(struct o2hb_region *reg)
{
reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
reg->hr_start_block, reg->hr_blocks);
mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
reg->hr_block_bytes, reg->hr_block_bits);
mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
}
static int o2hb_map_slot_data(struct o2hb_region *reg)
{
int i, j;
unsigned int last_slot;
unsigned int spp = reg->hr_slots_per_page;
struct page *page;
char *raw;
struct o2hb_disk_slot *slot;
reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
if (reg->hr_tmp_block == NULL) {
mlog_errno(-ENOMEM);
return -ENOMEM;
}
reg->hr_slots = kcalloc(reg->hr_blocks,
sizeof(struct o2hb_disk_slot), GFP_KERNEL);
if (reg->hr_slots == NULL) {
mlog_errno(-ENOMEM);
return -ENOMEM;
}
for(i = 0; i < reg->hr_blocks; i++) {
slot = &reg->hr_slots[i];
slot->ds_node_num = i;
INIT_LIST_HEAD(&slot->ds_live_item);
slot->ds_raw_block = NULL;
}
reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
"at %u blocks per page\n",
reg->hr_num_pages, reg->hr_blocks, spp);
reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
GFP_KERNEL);
if (!reg->hr_slot_data) {
mlog_errno(-ENOMEM);
return -ENOMEM;
}
for(i = 0; i < reg->hr_num_pages; i++) {
page = alloc_page(GFP_KERNEL);
if (!page) {
mlog_errno(-ENOMEM);
return -ENOMEM;
}
reg->hr_slot_data[i] = page;
last_slot = i * spp;
raw = page_address(page);
for (j = 0;
(j < spp) && ((j + last_slot) < reg->hr_blocks);
j++) {
BUG_ON((j + last_slot) >= reg->hr_blocks);
slot = &reg->hr_slots[j + last_slot];
slot->ds_raw_block =
(struct o2hb_disk_heartbeat_block *) raw;
raw += reg->hr_block_bytes;
}
}
return 0;
}
/* Read in all the slots available and populate the tracking
* structures so that we can start with a baseline idea of what's
* there. */
static int o2hb_populate_slot_data(struct o2hb_region *reg)
{
int ret, i;
struct o2hb_disk_slot *slot;
struct o2hb_disk_heartbeat_block *hb_block;
mlog_entry_void();
ret = o2hb_read_slots(reg, reg->hr_blocks);
if (ret) {
mlog_errno(ret);
goto out;
}
/* We only want to get an idea of the values initially in each
* slot, so we do no verification - o2hb_check_slot will
* actually determine if each configured slot is valid and
* whether any values have changed. */
for(i = 0; i < reg->hr_blocks; i++) {
slot = &reg->hr_slots[i];
hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
/* Only fill the values that o2hb_check_slot uses to
* determine changing slots */
slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
}
out:
mlog_exit(ret);
return ret;
}
/* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
const char *page,
size_t count)
{
struct task_struct *hb_task;
long fd;
int sectsize;
char *p = (char *)page;
struct file *filp = NULL;
struct inode *inode = NULL;
ssize_t ret = -EINVAL;
if (reg->hr_bdev)
goto out;
/* We can't heartbeat without having had our node number
* configured yet. */
if (o2nm_this_node() == O2NM_MAX_NODES)
goto out;
fd = simple_strtol(p, &p, 0);
if (!p || (*p && (*p != '\n')))
goto out;
if (fd < 0 || fd >= INT_MAX)
goto out;
filp = fget(fd);
if (filp == NULL)
goto out;
if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
reg->hr_block_bytes == 0)
goto out;
inode = igrab(filp->f_mapping->host);
if (inode == NULL)
goto out;
if (!S_ISBLK(inode->i_mode))
goto out;
reg->hr_bdev = I_BDEV(filp->f_mapping->host);
ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ);
if (ret) {
reg->hr_bdev = NULL;
goto out;
}
inode = NULL;
bdevname(reg->hr_bdev, reg->hr_dev_name);
sectsize = bdev_hardsect_size(reg->hr_bdev);
if (sectsize != reg->hr_block_bytes) {
mlog(ML_ERROR,
"blocksize %u incorrect for device, expected %d",
reg->hr_block_bytes, sectsize);
ret = -EINVAL;
goto out;
}
o2hb_init_region_params(reg);
/* Generation of zero is invalid */
do {
get_random_bytes(&reg->hr_generation,
sizeof(reg->hr_generation));
} while (reg->hr_generation == 0);
ret = o2hb_map_slot_data(reg);
if (ret) {
mlog_errno(ret);
goto out;
}
ret = o2hb_populate_slot_data(reg);
if (ret) {
mlog_errno(ret);
goto out;
}
INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
/*
* A node is considered live after it has beat LIVE_THRESHOLD
* times. We're not steady until we've given them a chance
* _after_ our first read.
*/
atomic_set(&reg->hr_steady_iterations, O2HB_LIVE_THRESHOLD + 1);
hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
reg->hr_item.ci_name);
if (IS_ERR(hb_task)) {
ret = PTR_ERR(hb_task);
mlog_errno(ret);
goto out;
}
spin_lock(&o2hb_live_lock);
reg->hr_task = hb_task;
spin_unlock(&o2hb_live_lock);
ret = wait_event_interruptible(o2hb_steady_queue,
atomic_read(&reg->hr_steady_iterations) == 0);
if (ret) {
/* We got interrupted (hello ptrace!). Clean up */
spin_lock(&o2hb_live_lock);
hb_task = reg->hr_task;
reg->hr_task = NULL;
spin_unlock(&o2hb_live_lock);
if (hb_task)
kthread_stop(hb_task);
goto out;
}
/* Ok, we were woken. Make sure it wasn't by drop_item() */
spin_lock(&o2hb_live_lock);
hb_task = reg->hr_task;
spin_unlock(&o2hb_live_lock);
if (hb_task)
ret = count;
else
ret = -EIO;
out:
if (filp)
fput(filp);
if (inode)
iput(inode);
if (ret < 0) {
if (reg->hr_bdev) {
blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
reg->hr_bdev = NULL;
}
}
return ret;
}
static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
char *page)
{
pid_t pid = 0;
spin_lock(&o2hb_live_lock);
if (reg->hr_task)
pid = task_pid_nr(reg->hr_task);
spin_unlock(&o2hb_live_lock);
if (!pid)
return 0;
return sprintf(page, "%u\n", pid);
}
struct o2hb_region_attribute {
struct configfs_attribute attr;
ssize_t (*show)(struct o2hb_region *, char *);
ssize_t (*store)(struct o2hb_region *, const char *, size_t);
};
static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
.attr = { .ca_owner = THIS_MODULE,
.ca_name = "block_bytes",
.ca_mode = S_IRUGO | S_IWUSR },
.show = o2hb_region_block_bytes_read,
.store = o2hb_region_block_bytes_write,
};
static struct o2hb_region_attribute o2hb_region_attr_start_block = {
.attr = { .ca_owner = THIS_MODULE,
.ca_name = "start_block",
.ca_mode = S_IRUGO | S_IWUSR },
.show = o2hb_region_start_block_read,
.store = o2hb_region_start_block_write,
};
static struct o2hb_region_attribute o2hb_region_attr_blocks = {
.attr = { .ca_owner = THIS_MODULE,
.ca_name = "blocks",
.ca_mode = S_IRUGO | S_IWUSR },
.show = o2hb_region_blocks_read,
.store = o2hb_region_blocks_write,
};
static struct o2hb_region_attribute o2hb_region_attr_dev = {
.attr = { .ca_owner = THIS_MODULE,
.ca_name = "dev",
.ca_mode = S_IRUGO | S_IWUSR },
.show = o2hb_region_dev_read,
.store = o2hb_region_dev_write,
};
static struct o2hb_region_attribute o2hb_region_attr_pid = {
.attr = { .ca_owner = THIS_MODULE,
.ca_name = "pid",
.ca_mode = S_IRUGO | S_IRUSR },
.show = o2hb_region_pid_read,
};
static struct configfs_attribute *o2hb_region_attrs[] = {
&o2hb_region_attr_block_bytes.attr,
&o2hb_region_attr_start_block.attr,
&o2hb_region_attr_blocks.attr,
&o2hb_region_attr_dev.attr,
&o2hb_region_attr_pid.attr,
NULL,
};
static ssize_t o2hb_region_show(struct config_item *item,
struct configfs_attribute *attr,
char *page)
{
struct o2hb_region *reg = to_o2hb_region(item);
struct o2hb_region_attribute *o2hb_region_attr =
container_of(attr, struct o2hb_region_attribute, attr);
ssize_t ret = 0;
if (o2hb_region_attr->show)
ret = o2hb_region_attr->show(reg, page);
return ret;
}
static ssize_t o2hb_region_store(struct config_item *item,
struct configfs_attribute *attr,
const char *page, size_t count)
{
struct o2hb_region *reg = to_o2hb_region(item);
struct o2hb_region_attribute *o2hb_region_attr =
container_of(attr, struct o2hb_region_attribute, attr);
ssize_t ret = -EINVAL;
if (o2hb_region_attr->store)
ret = o2hb_region_attr->store(reg, page, count);
return ret;
}
static struct configfs_item_operations o2hb_region_item_ops = {
.release = o2hb_region_release,
.show_attribute = o2hb_region_show,
.store_attribute = o2hb_region_store,
};
static struct config_item_type o2hb_region_type = {
.ct_item_ops = &o2hb_region_item_ops,
.ct_attrs = o2hb_region_attrs,
.ct_owner = THIS_MODULE,
};
/* heartbeat set */
struct o2hb_heartbeat_group {
struct config_group hs_group;
/* some stuff? */
};
static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
{
return group ?
container_of(group, struct o2hb_heartbeat_group, hs_group)
: NULL;
}
static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
const char *name)
{
struct o2hb_region *reg = NULL;
reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
if (reg == NULL)
return ERR_PTR(-ENOMEM);
config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
spin_lock(&o2hb_live_lock);
list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
spin_unlock(&o2hb_live_lock);
return &reg->hr_item;
}
static void o2hb_heartbeat_group_drop_item(struct config_group *group,
struct config_item *item)
{
struct task_struct *hb_task;
struct o2hb_region *reg = to_o2hb_region(item);
/* stop the thread when the user removes the region dir */
spin_lock(&o2hb_live_lock);
hb_task = reg->hr_task;
reg->hr_task = NULL;
spin_unlock(&o2hb_live_lock);
if (hb_task)
kthread_stop(hb_task);
/*
* If we're racing a dev_write(), we need to wake them. They will
* check reg->hr_task
*/
if (atomic_read(&reg->hr_steady_iterations) != 0) {
atomic_set(&reg->hr_steady_iterations, 0);
wake_up(&o2hb_steady_queue);
}
config_item_put(item);
}
struct o2hb_heartbeat_group_attribute {
struct configfs_attribute attr;
ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
};
static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
struct configfs_attribute *attr,
char *page)
{
struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
ssize_t ret = 0;
if (o2hb_heartbeat_group_attr->show)
ret = o2hb_heartbeat_group_attr->show(reg, page);
return ret;
}
static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
struct configfs_attribute *attr,
const char *page, size_t count)
{
struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
ssize_t ret = -EINVAL;
if (o2hb_heartbeat_group_attr->store)
ret = o2hb_heartbeat_group_attr->store(reg, page, count);
return ret;
}
static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
char *page)
{
return sprintf(page, "%u\n", o2hb_dead_threshold);
}
static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
const char *page,
size_t count)
{
unsigned long tmp;
char *p = (char *)page;
tmp = simple_strtoul(p, &p, 10);
if (!p || (*p && (*p != '\n')))
return -EINVAL;
/* this will validate ranges for us. */
o2hb_dead_threshold_set((unsigned int) tmp);
return count;
}
static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
.attr = { .ca_owner = THIS_MODULE,
.ca_name = "dead_threshold",
.ca_mode = S_IRUGO | S_IWUSR },
.show = o2hb_heartbeat_group_threshold_show,
.store = o2hb_heartbeat_group_threshold_store,
};
static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
&o2hb_heartbeat_group_attr_threshold.attr,
NULL,
};
static struct configfs_item_operations o2hb_hearbeat_group_item_ops = {
.show_attribute = o2hb_heartbeat_group_show,
.store_attribute = o2hb_heartbeat_group_store,
};
static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
.make_item = o2hb_heartbeat_group_make_item,
.drop_item = o2hb_heartbeat_group_drop_item,
};
static struct config_item_type o2hb_heartbeat_group_type = {
.ct_group_ops = &o2hb_heartbeat_group_group_ops,
.ct_item_ops = &o2hb_hearbeat_group_item_ops,
.ct_attrs = o2hb_heartbeat_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 *o2hb_alloc_hb_set(void)
{
struct o2hb_heartbeat_group *hs = NULL;
struct config_group *ret = NULL;
hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
if (hs == NULL)
goto out;
config_group_init_type_name(&hs->hs_group, "heartbeat",
&o2hb_heartbeat_group_type);
ret = &hs->hs_group;
out:
if (ret == NULL)
kfree(hs);
return ret;
}
void o2hb_free_hb_set(struct config_group *group)
{
struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
kfree(hs);
}
/* hb callback registration and issueing */
static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
{
if (type == O2HB_NUM_CB)
return ERR_PTR(-EINVAL);
return &o2hb_callbacks[type];
}
void o2hb_setup_callback(struct o2hb_callback_func *hc,
enum o2hb_callback_type type,
o2hb_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 = O2HB_CB_MAGIC;
}
EXPORT_SYMBOL_GPL(o2hb_setup_callback);
static struct o2hb_region *o2hb_find_region(const char *region_uuid)
{
struct o2hb_region *p, *reg = NULL;
assert_spin_locked(&o2hb_live_lock);
list_for_each_entry(p, &o2hb_all_regions, hr_all_item) {
if (!strcmp(region_uuid, config_item_name(&p->hr_item))) {
reg = p;
break;
}
}
return reg;
}
static int o2hb_region_get(const char *region_uuid)
{
int ret = 0;
struct o2hb_region *reg;
spin_lock(&o2hb_live_lock);
reg = o2hb_find_region(region_uuid);
if (!reg)
ret = -ENOENT;
spin_unlock(&o2hb_live_lock);
if (ret)
goto out;
ret = o2nm_depend_this_node();
if (ret)
goto out;
ret = o2nm_depend_item(&reg->hr_item);
if (ret)
o2nm_undepend_this_node();
out:
return ret;
}
static void o2hb_region_put(const char *region_uuid)
{
struct o2hb_region *reg;
spin_lock(&o2hb_live_lock);
reg = o2hb_find_region(region_uuid);
spin_unlock(&o2hb_live_lock);
if (reg) {
o2nm_undepend_item(&reg->hr_item);
o2nm_undepend_this_node();
}
}
int o2hb_register_callback(const char *region_uuid,
struct o2hb_callback_func *hc)
{
struct o2hb_callback_func *tmp;
struct list_head *iter;
struct o2hb_callback *hbcall;
int ret;
BUG_ON(hc->hc_magic != O2HB_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;
}
if (region_uuid) {
ret = o2hb_region_get(region_uuid);
if (ret)
goto out;
}
down_write(&o2hb_callback_sem);
list_for_each(iter, &hbcall->list) {
tmp = list_entry(iter, struct o2hb_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(&o2hb_callback_sem);
ret = 0;
out:
mlog(ML_HEARTBEAT, "returning %d on behalf of %p for funcs %p\n",
ret, __builtin_return_address(0), hc);
return ret;
}
EXPORT_SYMBOL_GPL(o2hb_register_callback);
void o2hb_unregister_callback(const char *region_uuid,
struct o2hb_callback_func *hc)
{
BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
mlog(ML_HEARTBEAT, "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;
if (region_uuid)
o2hb_region_put(region_uuid);
down_write(&o2hb_callback_sem);
list_del_init(&hc->hc_item);
up_write(&o2hb_callback_sem);
}
EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
int o2hb_check_node_heartbeating(u8 node_num)
{
unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
o2hb_fill_node_map(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(o2hb_check_node_heartbeating);
int o2hb_check_node_heartbeating_from_callback(u8 node_num)
{
unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
o2hb_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(o2hb_check_node_heartbeating_from_callback);
/* Makes sure our local node is configured with a node number, and is
* heartbeating. */
int o2hb_check_local_node_heartbeating(void)
{
u8 node_num;
/* if this node was set then we have networking */
node_num = o2nm_this_node();
if (node_num == O2NM_MAX_NODES) {
mlog(ML_HEARTBEAT, "this node has not been configured.\n");
return 0;
}
return o2hb_check_node_heartbeating(node_num);
}
EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
/*
* 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.
*/
void o2hb_stop_all_regions(void)
{
struct o2hb_region *reg;
mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
spin_lock(&o2hb_live_lock);
list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
reg->hr_unclean_stop = 1;
spin_unlock(&o2hb_live_lock);
}
EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
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