/******************************************************************************
*******************************************************************************
**
** Copyright (C) 2005-2010 Red Hat, Inc. All rights reserved.
**
** This copyrighted material is made available to anyone wishing to use,
** modify, copy, or redistribute it subject to the terms and conditions
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
/* Central locking logic has four stages:
dlm_lock()
dlm_unlock()
request_lock(ls, lkb)
convert_lock(ls, lkb)
unlock_lock(ls, lkb)
cancel_lock(ls, lkb)
_request_lock(r, lkb)
_convert_lock(r, lkb)
_unlock_lock(r, lkb)
_cancel_lock(r, lkb)
do_request(r, lkb)
do_convert(r, lkb)
do_unlock(r, lkb)
do_cancel(r, lkb)
Stage 1 (lock, unlock) is mainly about checking input args and
splitting into one of the four main operations:
dlm_lock = request_lock
dlm_lock+CONVERT = convert_lock
dlm_unlock = unlock_lock
dlm_unlock+CANCEL = cancel_lock
Stage 2, xxxx_lock(), just finds and locks the relevant rsb which is
provided to the next stage.
Stage 3, _xxxx_lock(), determines if the operation is local or remote.
When remote, it calls send_xxxx(), when local it calls do_xxxx().
Stage 4, do_xxxx(), is the guts of the operation. It manipulates the
given rsb and lkb and queues callbacks.
For remote operations, send_xxxx() results in the corresponding do_xxxx()
function being executed on the remote node. The connecting send/receive
calls on local (L) and remote (R) nodes:
L: send_xxxx() -> R: receive_xxxx()
R: do_xxxx()
L: receive_xxxx_reply() <- R: send_xxxx_reply()
*/
#include <linux/types.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include "dlm_internal.h"
#include <linux/dlm_device.h>
#include "memory.h"
#include "lowcomms.h"
#include "requestqueue.h"
#include "util.h"
#include "dir.h"
#include "member.h"
#include "lockspace.h"
#include "ast.h"
#include "lock.h"
#include "rcom.h"
#include "recover.h"
#include "lvb_table.h"
#include "user.h"
#include "config.h"
static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode);
static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_remove(struct dlm_rsb *r);
static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
struct dlm_message *ms);
static int receive_extralen(struct dlm_message *ms);
static void do_purge(struct dlm_ls *ls, int nodeid, int pid);
static void del_timeout(struct dlm_lkb *lkb);
static void toss_rsb(struct kref *kref);
/*
* Lock compatibilty matrix - thanks Steve
* UN = Unlocked state. Not really a state, used as a flag
* PD = Padding. Used to make the matrix a nice power of two in size
* Other states are the same as the VMS DLM.
* Usage: matrix[grmode+1][rqmode+1] (although m[rq+1][gr+1] is the same)
*/
static const int __dlm_compat_matrix[8][8] = {
/* UN NL CR CW PR PW EX PD */
{1, 1, 1, 1, 1, 1, 1, 0}, /* UN */
{1, 1, 1, 1, 1, 1, 1, 0}, /* NL */
{1, 1, 1, 1, 1, 1, 0, 0}, /* CR */
{1, 1, 1, 1, 0, 0, 0, 0}, /* CW */
{1, 1, 1, 0, 1, 0, 0, 0}, /* PR */
{1, 1, 1, 0, 0, 0, 0, 0}, /* PW */
{1, 1, 0, 0, 0, 0, 0, 0}, /* EX */
{0, 0, 0, 0, 0, 0, 0, 0} /* PD */
};
/*
* This defines the direction of transfer of LVB data.
* Granted mode is the row; requested mode is the column.
* Usage: matrix[grmode+1][rqmode+1]
* 1 = LVB is returned to the caller
* 0 = LVB is written to the resource
* -1 = nothing happens to the LVB
*/
const int dlm_lvb_operations[8][8] = {
/* UN NL CR CW PR PW EX PD*/
{ -1, 1, 1, 1, 1, 1, 1, -1 }, /* UN */
{ -1, 1, 1, 1, 1, 1, 1, 0 }, /* NL */
{ -1, -1, 1, 1, 1, 1, 1, 0 }, /* CR */
{ -1, -1, -1, 1, 1, 1, 1, 0 }, /* CW */
{ -1, -1, -1, -1, 1, 1, 1, 0 }, /* PR */
{ -1, 0, 0, 0, 0, 0, 1, 0 }, /* PW */
{ -1, 0, 0, 0, 0, 0, 0, 0 }, /* EX */
{ -1, 0, 0, 0, 0, 0, 0, 0 } /* PD */
};
#define modes_compat(gr, rq) \
__dlm_compat_matrix[(gr)->lkb_grmode + 1][(rq)->lkb_rqmode + 1]
int dlm_modes_compat(int mode1, int mode2)
{
return __dlm_compat_matrix[mode1 + 1][mode2 + 1];
}
/*
* Compatibility matrix for conversions with QUECVT set.
* Granted mode is the row; requested mode is the column.
* Usage: matrix[grmode+1][rqmode+1]
*/
static const int __quecvt_compat_matrix[8][8] = {
/* UN NL CR CW PR PW EX PD */
{0, 0, 0, 0, 0, 0, 0, 0}, /* UN */
{0, 0, 1, 1, 1, 1, 1, 0}, /* NL */
{0, 0, 0, 1, 1, 1, 1, 0}, /* CR */
{0, 0, 0, 0, 1, 1, 1, 0}, /* CW */
{0, 0, 0, 1, 0, 1, 1, 0}, /* PR */
{0, 0, 0, 0, 0, 0, 1, 0}, /* PW */
{0, 0, 0, 0, 0, 0, 0, 0}, /* EX */
{0, 0, 0, 0, 0, 0, 0, 0} /* PD */
};
void dlm_print_lkb(struct dlm_lkb *lkb)
{
printk(KERN_ERR "lkb: nodeid %d id %x remid %x exflags %x flags %x "
"sts %d rq %d gr %d wait_type %d wait_nodeid %d seq %llu\n",
lkb->lkb_nodeid, lkb->lkb_id, lkb->lkb_remid, lkb->lkb_exflags,
lkb->lkb_flags, lkb->lkb_status, lkb->lkb_rqmode,
lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_wait_nodeid,
(unsigned long long)lkb->lkb_recover_seq);
}
static void dlm_print_rsb(struct dlm_rsb *r)
{
printk(KERN_ERR "rsb: nodeid %d master %d dir %d flags %lx first %x "
"rlc %d name %s\n",
r->res_nodeid, r->res_master_nodeid, r->res_dir_nodeid,
r->res_flags, r->res_first_lkid, r->res_recover_locks_count,
r->res_name);
}
void dlm_dump_rsb(struct dlm_rsb *r)
{
struct dlm_lkb *lkb;
dlm_print_rsb(r);
printk(KERN_ERR "rsb: root_list empty %d recover_list empty %d\n",
list_empty(&r->res_root_list), list_empty(&r->res_recover_list));
printk(KERN_ERR "rsb lookup list\n");
list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup)
dlm_print_lkb(lkb);
printk(KERN_ERR "rsb grant queue:\n");
list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue)
dlm_print_lkb(lkb);
printk(KERN_ERR "rsb convert queue:\n");
list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue)
dlm_print_lkb(lkb);
printk(KERN_ERR "rsb wait queue:\n");
list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue)
dlm_print_lkb(lkb);
}
/* Threads cannot use the lockspace while it's being recovered */
static inline void dlm_lock_recovery(struct dlm_ls *ls)
{
down_read(&ls->ls_in_recovery);
}
void dlm_unlock_recovery(struct dlm_ls *ls)
{
up_read(&ls->ls_in_recovery);
}
int dlm_lock_recovery_try(struct dlm_ls *ls)
{
return down_read_trylock(&ls->ls_in_recovery);
}
static inline int can_be_queued(struct dlm_lkb *lkb)
{
return !(lkb->lkb_exflags & DLM_LKF_NOQUEUE);
}
static inline int force_blocking_asts(struct dlm_lkb *lkb)
{
return (lkb->lkb_exflags & DLM_LKF_NOQUEUEBAST);
}
static inline int is_demoted(struct dlm_lkb *lkb)
{
return (lkb->lkb_sbflags & DLM_SBF_DEMOTED);
}
static inline int is_altmode(struct dlm_lkb *lkb)
{
return (lkb->lkb_sbflags & DLM_SBF_ALTMODE);
}
static inline int is_granted(struct dlm_lkb *lkb)
{
return (lkb->lkb_status == DLM_LKSTS_GRANTED);
}
static inline int is_remote(struct dlm_rsb *r)
{
DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r););
return !!r->res_nodeid;
}
static inline int is_process_copy(struct dlm_lkb *lkb)
{
return (lkb->lkb_nodeid && !(lkb->lkb_flags & DLM_IFL_MSTCPY));
}
static inline int is_master_copy(struct dlm_lkb *lkb)
{
return (lkb->lkb_flags & DLM_IFL_MSTCPY) ? 1 : 0;
}
static inline int middle_conversion(struct dlm_lkb *lkb)
{
if ((lkb->lkb_grmode==DLM_LOCK_PR && lkb->lkb_rqmode==DLM_LOCK_CW) ||
(lkb->lkb_rqmode==DLM_LOCK_PR && lkb->lkb_grmode==DLM_LOCK_CW))
return 1;
return 0;
}
static inline int down_conversion(struct dlm_lkb *lkb)
{
return (!middle_conversion(lkb) && lkb->lkb_rqmode < lkb->lkb_grmode);
}
static inline int is_overlap_unlock(struct dlm_lkb *lkb)
{
return lkb->lkb_flags & DLM_IFL_OVERLAP_UNLOCK;
}
static inline int is_overlap_cancel(struct dlm_lkb *lkb)
{
return lkb->lkb_flags & DLM_IFL_OVERLAP_CANCEL;
}
static inline int is_overlap(struct dlm_lkb *lkb)
{
return (lkb->lkb_flags & (DLM_IFL_OVERLAP_UNLOCK |
DLM_IFL_OVERLAP_CANCEL));
}
static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
if (is_master_copy(lkb))
return;
del_timeout(lkb);
DLM_ASSERT(lkb->lkb_lksb, dlm_print_lkb(lkb););
/* if the operation was a cancel, then return -DLM_ECANCEL, if a
timeout caused the cancel then return -ETIMEDOUT */
if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_TIMEOUT_CANCEL)) {
lkb->lkb_flags &= ~DLM_IFL_TIMEOUT_CANCEL;
rv = -ETIMEDOUT;
}
if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_DEADLOCK_CANCEL)) {
lkb->lkb_flags &= ~DLM_IFL_DEADLOCK_CANCEL;
rv = -EDEADLK;
}
dlm_add_cb(lkb, DLM_CB_CAST, lkb->lkb_grmode, rv, lkb->lkb_sbflags);
}
static inline void queue_cast_overlap(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
queue_cast(r, lkb,
is_overlap_unlock(lkb) ? -DLM_EUNLOCK : -DLM_ECANCEL);
}
static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
{
if (is_master_copy(lkb)) {
send_bast(r, lkb, rqmode);
} else {
dlm_add_cb(lkb, DLM_CB_BAST, rqmode, 0, 0);
}
}
/*
* Basic operations on rsb's and lkb's
*/
/* This is only called to add a reference when the code already holds
a valid reference to the rsb, so there's no need for locking. */
static inline void hold_rsb(struct dlm_rsb *r)
{
kref_get(&r->res_ref);
}
void dlm_hold_rsb(struct dlm_rsb *r)
{
hold_rsb(r);
}
/* When all references to the rsb are gone it's transferred to
the tossed list for later disposal. */
static void put_rsb(struct dlm_rsb *r)
{
struct dlm_ls *ls = r->res_ls;
uint32_t bucket = r->res_bucket;
spin_lock(&ls->ls_rsbtbl[bucket].lock);
kref_put(&r->res_ref, toss_rsb);
spin_unlock(&ls->ls_rsbtbl[bucket].lock);
}
void dlm_put_rsb(struct dlm_rsb *r)
{
put_rsb(r);
}
static int pre_rsb_struct(struct dlm_ls *ls)
{
struct dlm_rsb *r1, *r2;
int count = 0;
spin_lock(&ls->ls_new_rsb_spin);
if (ls->ls_new_rsb_count > dlm_config.ci_new_rsb_count / 2) {
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