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DEFINITIONS
This source file includes following definitions.
- dlm_init_lock_cache
- dlm_destroy_lock_cache
- dlm_can_grant_new_lock
- dlmlock_master
- dlm_revert_pending_lock
- dlmlock_remote
- dlm_send_remote_lock_request
- dlm_lock_get
- dlm_lock_put
- dlm_lock_release
- dlm_lock_attach_lockres
- dlm_lock_detach_lockres
- dlm_init_lock
- dlm_new_lock
- dlm_create_lock_handler
- dlm_get_next_cookie
- dlmlock
/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* dlmlock.c
*
* underlying calls for lock creation
*
* Copyright (C) 2004 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/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"
#include "dlmapi.h"
#include "dlmcommon.h"
#include "dlmconvert.h"
#define MLOG_MASK_PREFIX ML_DLM
#include "cluster/masklog.h"
static struct kmem_cache *dlm_lock_cache = NULL;
static DEFINE_SPINLOCK(dlm_cookie_lock);
static u64 dlm_next_cookie = 1;
static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_lock *lock, int flags);
static void dlm_init_lock(struct dlm_lock *newlock, int type,
u8 node, u64 cookie);
static void dlm_lock_release(struct kref *kref);
static void dlm_lock_detach_lockres(struct dlm_lock *lock);
int dlm_init_lock_cache(void)
{
dlm_lock_cache = kmem_cache_create("o2dlm_lock",
sizeof(struct dlm_lock),
0, SLAB_HWCACHE_ALIGN, NULL);
if (dlm_lock_cache == NULL)
return -ENOMEM;
return 0;
}
void dlm_destroy_lock_cache(void)
{
if (dlm_lock_cache)
kmem_cache_destroy(dlm_lock_cache);
}
/* Tell us whether we can grant a new lock request.
* locking:
* caller needs: res->spinlock
* taken: none
* held on exit: none
* returns: 1 if the lock can be granted, 0 otherwise.
*/
static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
struct dlm_lock *lock)
{
struct list_head *iter;
struct dlm_lock *tmplock;
list_for_each(iter, &res->granted) {
tmplock = list_entry(iter, struct dlm_lock, list);
if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
return 0;
}
list_for_each(iter, &res->converting) {
tmplock = list_entry(iter, struct dlm_lock, list);
if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
return 0;
}
return 1;
}
/* performs lock creation at the lockres master site
* locking:
* caller needs: none
* taken: takes and drops res->spinlock
* held on exit: none
* returns: DLM_NORMAL, DLM_NOTQUEUED
*/
static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_lock *lock, int flags)
{
int call_ast = 0, kick_thread = 0;
enum dlm_status status = DLM_NORMAL;
mlog_entry("type=%d\n", lock->ml.type);
spin_lock(&res->spinlock);
/* if called from dlm_create_lock_handler, need to
* ensure it will not sleep in dlm_wait_on_lockres */
status = __dlm_lockres_state_to_status(res);
if (status != DLM_NORMAL &&
lock->ml.node != dlm->node_num) {
/* erf. state changed after lock was dropped. */
spin_unlock(&res->spinlock);
dlm_error(status);
return status;
}
__dlm_wait_on_lockres(res);
__dlm_lockres_reserve_ast(res);
if (dlm_can_grant_new_lock(res, lock)) {
mlog(0, "I can grant this lock right away\n");
/* got it right away */
lock->lksb->status = DLM_NORMAL;
status = DLM_NORMAL;
dlm_lock_get(lock);
list_add_tail(&lock->list, &res->granted);
/* for the recovery lock, we can't allow the ast
* to be queued since the dlmthread is already
* frozen. but the recovery lock is always locked
* with LKM_NOQUEUE so we do not need the ast in
* this special case */
if (!dlm_is_recovery_lock(res->lockname.name,
res->lockname.len)) {
kick_thread = 1;
call_ast = 1;
} else {
mlog(0, "%s: returning DLM_NORMAL to "
"node %u for reco lock\n", dlm->name,
lock->ml.node);
}
} else {
/* for NOQUEUE request, unless we get the
* lock right away, return DLM_NOTQUEUED */
if (flags & LKM_NOQUEUE) {
status = DLM_NOTQUEUED;
if (dlm_is_recovery_lock(res->lockname.name,
res->lockname.len)) {
mlog(0, "%s: returning NOTQUEUED to "
"node %u for reco lock\n", dlm->name,
lock->ml.node);
}
} else {
dlm_lock_get(lock);
list_add_tail(&lock->list, &res->blocked);
kick_thread = 1;
}
}
/* reduce the inflight count, this may result in the lockres
* being purged below during calc_usage */
if (lock->ml.node == dlm->node_num)
dlm_lockres_drop_inflight_ref(dlm, res);
spin_unlock(&res->spinlock);
wake_up(&res->wq);
/* either queue the ast or release it */
if (call_ast)
dlm_queue_ast(dlm, lock);
else
dlm_lockres_release_ast(dlm, res);
dlm_lockres_calc_usage(dlm, res);
if (kick_thread)
dlm_kick_thread(dlm, res);
return status;
}
void dlm_revert_pending_lock(struct dlm_lock_resource *res,
struct dlm_lock *lock)
{
/* remove from local queue if it failed */
list_del_init(&lock->list);
lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
}
/*
* locking:
* caller needs: none
* taken: takes and drops res->spinlock
* held on exit: none
* returns: DLM_DENIED, DLM_RECOVERING, or net status
*/
static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_lock *lock, int flags)
{
enum dlm_status status = DLM_DENIED;
int lockres_changed = 1;
mlog_entry("type=%d\n", lock->ml.type);
mlog(0, "lockres %.*s, flags = 0x%x\n", res->lockname.len,
res->lockname.name, flags);
spin_lock(&res->spinlock);
/* will exit this call with spinlock held */
__dlm_wait_on_lockres(res);
res->state |= DLM_LOCK_RES_IN_PROGRESS;
/* add lock to local (secondary) queue */
dlm_lock_get(lock);
list_add_tail(&lock->list, &res->blocked);
lock->lock_pending = 1;
spin_unlock(&res->spinlock);
/* spec seems to say that you will get DLM_NORMAL when the lock
* has been queued, meaning we need to wait for a reply here. */
status = dlm_send_remote_lock_request(dlm, res, lock, flags);
spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
lock->lock_pending = 0;
if (status != DLM_NORMAL) {
if (status == DLM_RECOVERING &&
dlm_is_recovery_lock(res->lockname.name,
res->lockname.len)) {
/* recovery lock was mastered by dead node.
* we need to have calc_usage shoot down this
* lockres and completely remaster it. */
mlog(0, "%s: recovery lock was owned by "
"dead node %u, remaster it now.\n",
dlm->name, res->owner);
} else if (status != DLM_NOTQUEUED) {
/*
* DO NOT call calc_usage, as this would unhash
* the remote lockres before we ever get to use
* it. treat as if we never made any change to
* the lockres.
*/
lockres_changed = 0;
dlm_error(status);
}
dlm_revert_pending_lock(res, lock);
dlm_lock_put(lock);
} else if (dlm_is_recovery_lock(res->lockname.name,
res->lockname.len)) {
/* special case for the $RECOVERY lock.
* there will never be an AST delivered to put
* this lock on the proper secondary queue
* (granted), so do it manually. */
mlog(0, "%s: $RECOVERY lock for this node (%u) is "
"mastered by %u; got lock, manually granting (no ast)\n",
dlm->name, dlm->node_num, res->owner);
list_move_tail(&lock->list, &res->granted);
}
spin_unlock(&res->spinlock);
if (lockres_changed)
dlm_lockres_calc_usage(dlm, res);
wake_up(&res->wq);
return status;
}
/* for remote lock creation.
* locking:
* caller needs: none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
* taken: none
* held on exit: none
* returns: DLM_NOLOCKMGR, or net status
*/
static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_lock *lock, int flags)
{
struct dlm_create_lock create;
int tmpret, status = 0;
enum dlm_status ret;
mlog_entry_void();
memset(&create, 0, sizeof(create));
create.node_idx = dlm->node_num;
create.requested_type = lock->ml.type;
create.cookie = lock->ml.cookie;
create.namelen = res->lockname.len;
create.flags = cpu_to_be32(flags);
memcpy(create.name, res->lockname.name, create.namelen);
tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
sizeof(create), res->owner, &status);
if (tmpret >= 0) {
// successfully sent and received
ret = status; // this is already a dlm_status
if (ret == DLM_REJECTED) {
mlog(ML_ERROR, "%s:%.*s: BUG. this is a stale lockres "
"no longer owned by %u. that node is coming back "
"up currently.\n", dlm->name, create.namelen,
create.name, res->owner);
dlm_print_one_lock_resource(res);
BUG();
}
} else {
mlog_errno(tmpret);
if (dlm_is_host_down(tmpret)) {
ret = DLM_RECOVERING;
mlog(0, "node %u died so returning DLM_RECOVERING "
"from lock message!\n", res->owner);
} else {
ret = dlm_err_to_dlm_status(tmpret);
}
}
return ret;
}
void dlm_lock_get(struct dlm_lock *lock)
{
kref_get(&lock->lock_refs);
}
void dlm_lock_put(struct dlm_lock *lock)
{
kref_put(&lock->lock_refs, dlm_lock_release);
}
static void dlm_lock_release(struct kref *kref)
{
struct dlm_lock *lock;
lock = container_of(kref, struct dlm_lock, lock_refs);
BUG_ON(!list_empty(&lock->list));
BUG_ON(!list_empty(&lock->ast_list));
BUG_ON(!list_empty(&lock->bast_list));
BUG_ON(lock->ast_pending);
BUG_ON(lock->bast_pending);
dlm_lock_detach_lockres(lock);
if (lock->lksb_kernel_allocated) {
mlog(0, "freeing kernel-allocated lksb\n");
kfree(lock->lksb);
}
kmem_cache_free(dlm_lock_cache, lock);
}
/* associate a lock with it's lockres, getting a ref on the lockres */
void dlm_lock_attach_lockres(struct dlm_lock *lock,
struct dlm_lock_resource *res)
{
dlm_lockres_get(res);
lock->lockres = res;
}
/* drop ref on lockres, if there is still one associated with lock */
static void dlm_lock_detach_lockres(struct dlm_lock *lock)
{
struct dlm_lock_resource *res;
res = lock->lockres;
if (res) {
lock->lockres = NULL;
mlog(0, "removing lock's lockres reference\n");
dlm_lockres_put(res);
}
}
static void dlm_init_lock(struct dlm_lock *newlock, int type,
u8 node, u64 cookie)
{
INIT_LIST_HEAD(&newlock->list);
INIT_LIST_HEAD(&newlock->ast_list);
INIT_LIST_HEAD(&newlock->bast_list);
spin_lock_init(&newlock->spinlock);
newlock->ml.type = type;
newlock->ml.convert_type = LKM_IVMODE;
newlock->ml.highest_blocked = LKM_IVMODE;
newlock->ml.node = node;
newlock->ml.pad1 = 0;
newlock->ml.list = 0;
newlock->ml.flags = 0;
newlock->ast = NULL;
newlock->bast = NULL;
newlock->astdata = NULL;
newlock->ml.cookie = cpu_to_be64(cookie);
newlock->ast_pending = 0;
newlock->bast_pending = 0;
newlock->convert_pending = 0;
newlock->lock_pending = 0;
newlock->unlock_pending = 0;
newlock->cancel_pending = 0;
newlock->lksb_kernel_allocated = 0;
kref_init(&newlock->lock_refs);
}
struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
struct dlm_lockstatus *lksb)
{
struct dlm_lock *lock;
int kernel_allocated = 0;
lock = (struct dlm_lock *) kmem_cache_zalloc(dlm_lock_cache, GFP_NOFS);
if (!lock)
return NULL;
if (!lksb) {
/* zero memory only if kernel-allocated */
lksb = kzalloc(sizeof(*lksb), GFP_NOFS);
if (!lksb) {
kfree(lock);
return NULL;
}
kernel_allocated = 1;
}
dlm_init_lock(lock, type, node, cookie);
if (kernel_allocated)
lock->lksb_kernel_allocated = 1;
lock->lksb = lksb;
lksb->lockid = lock;
return lock;
}
/* handler for lock creation net message
* locking:
* caller needs: none
* taken: takes and drops res->spinlock
* held on exit: none
* returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
*/
int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data)
{
struct dlm_ctxt *dlm = data;
struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
struct dlm_lock_resource *res = NULL;
struct dlm_lock *newlock = NULL;
struct dlm_lockstatus *lksb = NULL;
enum dlm_status status = DLM_NORMAL;
char *name;
unsigned int namelen;
BUG_ON(!dlm);
mlog_entry_void();
if (!dlm_grab(dlm))
return DLM_REJECTED;
name = create->name;
namelen = create->namelen;
status = DLM_REJECTED;
if (!dlm_domain_fully_joined(dlm)) {
mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
"sending a create_lock message for lock %.*s!\n",
dlm->name, create->node_idx, namelen, name);
dlm_error(status);
goto leave;
}
status = DLM_IVBUFLEN;
if (namelen > DLM_LOCKID_NAME_MAX) {
dlm_error(status);
goto leave;
}
status = DLM_SYSERR;
newlock = dlm_new_lock(create->requested_type,
create->node_idx,
be64_to_cpu(create->cookie), NULL);
if (!newlock) {
dlm_error(status);
goto leave;
}
lksb = newlock->lksb;
if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
lksb->flags |= DLM_LKSB_GET_LVB;
mlog(0, "set DLM_LKSB_GET_LVB flag\n");
}
status = DLM_IVLOCKID;
res = dlm_lookup_lockres(dlm, name, namelen);
if (!res) {
dlm_error(status);
goto leave;
}
spin_lock(&res->spinlock);
status = __dlm_lockres_state_to_status(res);
spin_unlock(&res->spinlock);
if (status != DLM_NORMAL) {
mlog(0, "lockres recovering/migrating/in-progress\n");
goto leave;
}
dlm_lock_attach_lockres(newlock, res);
status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
leave:
if (status != DLM_NORMAL)
if (newlock)
dlm_lock_put(newlock);
if (res)
dlm_lockres_put(res);
dlm_put(dlm);
return status;
}
/* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
{
u64 tmpnode = node_num;
/* shift single byte of node num into top 8 bits */
tmpnode <<= 56;
spin_lock(&dlm_cookie_lock);
*cookie = (dlm_next_cookie | tmpnode);
if (++dlm_next_cookie & 0xff00000000000000ull) {
mlog(0, "This node's cookie will now wrap!\n");
dlm_next_cookie = 1;
}
spin_unlock(&dlm_cookie_lock);
}
enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
struct dlm_lockstatus *lksb, int flags,
const char *name, int namelen, dlm_astlockfunc_t *ast,
void *data, dlm_bastlockfunc_t *bast)
{
enum dlm_status status;
struct dlm_lock_resource *res = NULL;
struct dlm_lock *lock = NULL;
int convert = 0, recovery = 0;
/* yes this function is a mess.
* TODO: clean this up. lots of common code in the
* lock and convert paths, especially in the retry blocks */
if (!lksb) {
dlm_error(DLM_BADARGS);
return DLM_BADARGS;
}
status = DLM_BADPARAM;
if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
dlm_error(status);
goto error;
}
if (flags & ~LKM_VALID_FLAGS) {
dlm_error(status);
goto error;
}
convert = (flags & LKM_CONVERT);
recovery = (flags & LKM_RECOVERY);
if (recovery &&
(!dlm_is_recovery_lock(name, namelen) || convert) ) {
dlm_error(status);
goto error;
}
if (convert && (flags & LKM_LOCAL)) {
mlog(ML_ERROR, "strange LOCAL convert request!\n");
goto error;
}
if (convert) {
/* CONVERT request */
/* if converting, must pass in a valid dlm_lock */
lock = lksb->lockid;
if (!lock) {
mlog(ML_ERROR, "NULL lock pointer in convert "
"request\n");
goto error;
}
res = lock->lockres;
if (!res) {
mlog(ML_ERROR, "NULL lockres pointer in convert "
"request\n");
goto error;
}
dlm_lockres_get(res);
/* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
* static after the original lock call. convert requests will
* ensure that everything is the same, or return DLM_BADARGS.
* this means that DLM_DENIED_NOASTS will never be returned.
*/
if (lock->lksb != lksb || lock->ast != ast ||
lock->bast != bast || lock->astdata != data) {
status = DLM_BADARGS;
mlog(ML_ERROR, "new args: lksb=%p, ast=%p, bast=%p, "
"astdata=%p\n", lksb, ast, bast, data);
mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
"astdata=%p\n", lock->lksb, lock->ast,
lock->bast, lock->astdata);
goto error;
}
retry_convert:
dlm_wait_for_recovery(dlm);
if (res->owner == dlm->node_num)
status = dlmconvert_master(dlm, res, lock, flags, mode);
else
status = dlmconvert_remote(dlm, res, lock, flags, mode);
if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
status == DLM_FORWARD) {
/* for now, see how this works without sleeping
* and just retry right away. I suspect the reco
* or migration will complete fast enough that
* no waiting will be necessary */
mlog(0, "retrying convert with migration/recovery/"
"in-progress\n");
msleep(100);
goto retry_convert;
}
} else {
u64 tmpcookie;
/* LOCK request */
status = DLM_BADARGS;
if (!name) {
dlm_error(status);
goto error;
}
status = DLM_IVBUFLEN;
if (namelen > DLM_LOCKID_NAME_MAX || namelen < 1) {
dlm_error(status);
goto error;
}
dlm_get_next_cookie(dlm->node_num, &tmpcookie);
lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
if (!lock) {
dlm_error(status);
goto error;
}
if (!recovery)
dlm_wait_for_recovery(dlm);
/* find or create the lock resource */
res = dlm_get_lock_resource(dlm, name, namelen, flags);
if (!res) {
status = DLM_IVLOCKID;
dlm_error(status);
goto error;
}
mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
dlm_lock_attach_lockres(lock, res);
lock->ast = ast;
lock->bast = bast;
lock->astdata = data;
retry_lock:
if (flags & LKM_VALBLK) {
mlog(0, "LKM_VALBLK passed by caller\n");
/* LVB requests for non PR, PW or EX locks are
* ignored. */
if (mode < LKM_PRMODE)
flags &= ~LKM_VALBLK;
else {
flags |= LKM_GET_LVB;
lock->lksb->flags |= DLM_LKSB_GET_LVB;
}
}
if (res->owner == dlm->node_num)
status = dlmlock_master(dlm, res, lock, flags);
else
status = dlmlock_remote(dlm, res, lock, flags);
if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
status == DLM_FORWARD) {
mlog(0, "retrying lock with migration/"
"recovery/in progress\n");
msleep(100);
/* no waiting for dlm_reco_thread */
if (recovery) {
if (status != DLM_RECOVERING)
goto retry_lock;
mlog(0, "%s: got RECOVERING "
"for $RECOVERY lock, master "
"was %u\n", dlm->name,
res->owner);
/* wait to see the node go down, then
* drop down and allow the lockres to
* get cleaned up. need to remaster. */
dlm_wait_for_node_death(dlm, res->owner,
DLM_NODE_DEATH_WAIT_MAX);
} else {
dlm_wait_for_recovery(dlm);
goto retry_lock;
}
}
if (status != DLM_NORMAL) {
lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
if (status != DLM_NOTQUEUED)
dlm_error(status);
goto error;
}
}
error:
if (status != DLM_NORMAL) {
if (lock && !convert)
dlm_lock_put(lock);
// this is kind of unnecessary
lksb->status = status;
}
/* put lockres ref from the convert path
* or from dlm_get_lock_resource */
if (res)
dlm_lockres_put(res);
return status;
}
EXPORT_SYMBOL_GPL(dlmlock);