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kernel-fxtec-pro1x/fs/gfs2/glock.h
Steven Whitehouse e66cf16109 GFS2: Use lockref for glocks 
Currently glocks have an atomic reference count and also a spinlock
which covers various internal fields, such as the state. This intent of
this patch is to replace the spinlock and the atomic reference count
with a lockref structure. This contains a spinlock which we can continue
to use as before, and a reference counter which is used in conjuction
with the spinlock to replace the previous atomic counter.

As a result of this there are some new rules for reference counting on
glocks. We need to distinguish between reference count changes under
gl_spin (which are now just increment or decrement of the new counter,
provided the count cannot hit zero) and those which are outside of
gl_spin, but which now take gl_spin internally.

The conversion is relatively straight forward. There is probably some
further clean up which can be done, but the priority at this stage is to
make the change in as simple a manner as possible.

A consequence of this change is that the reference count is being
decoupled from the lru list processing. This should allow future
adoption of the lru_list code with glocks in due course.

The reason for using the "dead" state and not just relying on 0 being
the "invalid state" is so that in due course 0 ref counts can be
allowable. The intent is to eventually be able to remove the ref count
changes which are currently hidden away in state_change().

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-10-15 15:18:08 +01:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 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 version 2.
*/
#ifndef __GLOCK_DOT_H__
#define __GLOCK_DOT_H__
#include <linux/sched.h>
#include <linux/parser.h>
#include "incore.h"
/* Options for hostdata parser */
enum {
Opt_jid,
Opt_id,
Opt_first,
Opt_nodir,
Opt_err,
};
/*
* lm_lockname types
*/
#define LM_TYPE_RESERVED 0x00
#define LM_TYPE_NONDISK 0x01
#define LM_TYPE_INODE 0x02
#define LM_TYPE_RGRP 0x03
#define LM_TYPE_META 0x04
#define LM_TYPE_IOPEN 0x05
#define LM_TYPE_FLOCK 0x06
#define LM_TYPE_PLOCK 0x07
#define LM_TYPE_QUOTA 0x08
#define LM_TYPE_JOURNAL 0x09
/*
* lm_lock() states
*
* SHARED is compatible with SHARED, not with DEFERRED or EX.
* DEFERRED is compatible with DEFERRED, not with SHARED or EX.
*/
#define LM_ST_UNLOCKED 0
#define LM_ST_EXCLUSIVE 1
#define LM_ST_DEFERRED 2
#define LM_ST_SHARED 3
/*
* lm_lock() flags
*
* LM_FLAG_TRY
* Don't wait to acquire the lock if it can't be granted immediately.
*
* LM_FLAG_TRY_1CB
* Send one blocking callback if TRY is set and the lock is not granted.
*
* LM_FLAG_NOEXP
* GFS sets this flag on lock requests it makes while doing journal recovery.
* These special requests should not be blocked due to the recovery like
* ordinary locks would be.
*
* LM_FLAG_ANY
* A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
* also be granted in SHARED. The preferred state is whichever is compatible
* with other granted locks, or the specified state if no other locks exist.
*
* LM_FLAG_PRIORITY
* Override fairness considerations. Suppose a lock is held in a shared state
* and there is a pending request for the deferred state. A shared lock
* request with the priority flag would be allowed to bypass the deferred
* request and directly join the other shared lock. A shared lock request
* without the priority flag might be forced to wait until the deferred
* requested had acquired and released the lock.
*/
#define LM_FLAG_TRY 0x00000001
#define LM_FLAG_TRY_1CB 0x00000002
#define LM_FLAG_NOEXP 0x00000004
#define LM_FLAG_ANY 0x00000008
#define LM_FLAG_PRIORITY 0x00000010
#define GL_ASYNC 0x00000040
#define GL_EXACT 0x00000080
#define GL_SKIP 0x00000100
#define GL_NOCACHE 0x00000400
/*
* lm_async_cb return flags
*
* LM_OUT_ST_MASK
* Masks the lower two bits of lock state in the returned value.
*
* LM_OUT_CANCELED
* The lock request was canceled.
*
*/
#define LM_OUT_ST_MASK 0x00000003
#define LM_OUT_CANCELED 0x00000008
#define LM_OUT_ERROR 0x00000004
/*
* lm_recovery_done() messages
*/
#define LM_RD_GAVEUP 308
#define LM_RD_SUCCESS 309
#define GLR_TRYFAILED 13
#define GL_GLOCK_MAX_HOLD (long)(HZ / 5)
#define GL_GLOCK_DFT_HOLD (long)(HZ / 5)
#define GL_GLOCK_MIN_HOLD (long)(10)
#define GL_GLOCK_HOLD_INCR (long)(HZ / 20)
#define GL_GLOCK_HOLD_DECR (long)(HZ / 40)
struct lm_lockops {
const char *lm_proto_name;
int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
void (*lm_first_done) (struct gfs2_sbd *sdp);
void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
unsigned int result);
void (*lm_unmount) (struct gfs2_sbd *sdp);
void (*lm_withdraw) (struct gfs2_sbd *sdp);
void (*lm_put_lock) (struct gfs2_glock *gl);
int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
unsigned int flags);
void (*lm_cancel) (struct gfs2_glock *gl);
const match_table_t *lm_tokens;
};
extern struct workqueue_struct *gfs2_delete_workqueue;
static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
{
struct gfs2_holder *gh;
struct pid *pid;
/* Look in glock's list of holders for one with current task as owner */
spin_lock(&gl->gl_spin);
pid = task_pid(current);
list_for_each_entry(gh, &gl->gl_holders, gh_list) {
if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
break;
if (gh->gh_owner_pid == pid)
goto out;
}
gh = NULL;
out:
spin_unlock(&gl->gl_spin);
return gh;
}
static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
{
return gl->gl_state == LM_ST_EXCLUSIVE;
}
static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
{
return gl->gl_state == LM_ST_DEFERRED;
}
static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
{
return gl->gl_state == LM_ST_SHARED;
}
static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
{
if (gl->gl_ops->go_flags & GLOF_ASPACE)
return (struct address_space *)(gl + 1);
return NULL;
}
extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
const struct gfs2_glock_operations *glops,
int create, struct gfs2_glock **glp);
extern void gfs2_glock_put(struct gfs2_glock *gl);
extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
unsigned flags, struct gfs2_holder *gh);
extern void gfs2_holder_reinit(unsigned int state, unsigned flags,
struct gfs2_holder *gh);
extern void gfs2_holder_uninit(struct gfs2_holder *gh);
extern int gfs2_glock_nq(struct gfs2_holder *gh);
extern int gfs2_glock_poll(struct gfs2_holder *gh);
extern int gfs2_glock_wait(struct gfs2_holder *gh);
extern void gfs2_glock_dq(struct gfs2_holder *gh);
extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
const struct gfs2_glock_operations *glops,
unsigned int state, int flags,
struct gfs2_holder *gh);
extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
extern int gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0)
extern __printf(2, 3)
void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
/**
* gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
* @gl: the glock
* @state: the state we're requesting
* @flags: the modifier flags
* @gh: the holder structure
*
* Returns: 0, GLR_*, or errno
*/
static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
unsigned int state, int flags,
struct gfs2_holder *gh)
{
int error;
gfs2_holder_init(gl, state, flags, gh);
error = gfs2_glock_nq(gh);
if (error)
gfs2_holder_uninit(gh);
return error;
}
extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
extern void gfs2_glock_free(struct gfs2_glock *gl);
extern int __init gfs2_glock_init(void);
extern void gfs2_glock_exit(void);
extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
extern int gfs2_register_debugfs(void);
extern void gfs2_unregister_debugfs(void);
extern const struct lm_lockops gfs2_dlm_ops;
#endif /* __GLOCK_DOT_H__ */
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