[people/ms/linux.git] / fs / gfs2 / glock.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 */

#ifndef __GLOCK_DOT_H__
#define __GLOCK_DOT_H__

#include <linux/sched.h>
#include <linux/parser.h>
#include "incore.h"
#include "util.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		0x0001
#define LM_FLAG_TRY_1CB		0x0002
#define LM_FLAG_NOEXP		0x0004
#define LM_FLAG_ANY		0x0008
#define LM_FLAG_PRIORITY	0x0010
#define GL_ASYNC		0x0040
#define GL_EXACT		0x0080
#define GL_SKIP			0x0100
#define GL_NOCACHE		0x0400
  
/*
 * 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_lockref.lock);
	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_lockref.lock);

	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_hold(struct gfs2_glock *gl);
extern void gfs2_glock_put(struct gfs2_glock *gl);
extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
			     u16 flags, struct gfs2_holder *gh);
extern void gfs2_holder_reinit(unsigned int state, u16 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, u16 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 void gfs2_dump_glock(struct seq_file *seq, 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, u16 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 void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
extern void gfs2_register_debugfs(void);
extern void gfs2_unregister_debugfs(void);

extern const struct lm_lockops gfs2_dlm_ops;

static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
{
	gh->gh_gl = NULL;
}

static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
{
	return gh->gh_gl;
}

/**
 * glock_set_object - set the gl_object field of a glock
 * @gl: the glock
 * @object: the object
 */
static inline void glock_set_object(struct gfs2_glock *gl, void *object)
{
	spin_lock(&gl->gl_lockref.lock);
	if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
		gfs2_dump_glock(NULL, gl);
	gl->gl_object = object;
	spin_unlock(&gl->gl_lockref.lock);
}

/**
 * glock_clear_object - clear the gl_object field of a glock
 * @gl: the glock
 * @object: the object
 *
 * I'd love to similarly add this:
 *	else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
 *		gfs2_dump_glock(NULL, gl);
 * Unfortunately, that's not possible because as soon as gfs2_delete_inode
 * frees the block in the rgrp, another process can reassign it for an I_NEW
 * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
 * That means gfs2_delete_inode may subsequently try to call this function
 * for a glock that's already pointing to a brand new inode. If we clear the
 * new inode's gl_object, we'll introduce metadata corruption. Function
 * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
 * tries to clear gl_object, so it's more than just gfs2_delete_inode.
 *
 */
static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
{
	spin_lock(&gl->gl_lockref.lock);
	if (gl->gl_object == object)
		gl->gl_object = NULL;
	spin_unlock(&gl->gl_lockref.lock);
}

#endif /* __GLOCK_DOT_H__ */
Commit	Line	Data
7336d0e6	1	/* SPDX-License-Identifier: GPL-2.0-only */
b3b94faa DT	2	/*
b3b94faa DT	3	* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3a8a9a10	4	* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
b3b94faa DT	5	*/
	6
	7	#ifndef __GLOCK_DOT_H__
	8	#define __GLOCK_DOT_H__
	9
e8edc6e0	10	#include <linux/sched.h>
f057f6cd	11	#include <linux/parser.h>
f2f7ba52	12	#include "incore.h"
df3d87bd	13	#include "util.h"
f2f7ba52	14
f057f6cd SW	15	/* Options for hostdata parser */
	16
	17	enum {
	18	Opt_jid,
	19	Opt_id,
	20	Opt_first,
	21	Opt_nodir,
	22	Opt_err,
	23	};
	24
	25	/*
	26	* lm_lockname types
	27	*/
	28
	29	#define LM_TYPE_RESERVED 0x00
	30	#define LM_TYPE_NONDISK 0x01
	31	#define LM_TYPE_INODE 0x02
	32	#define LM_TYPE_RGRP 0x03
	33	#define LM_TYPE_META 0x04
	34	#define LM_TYPE_IOPEN 0x05
	35	#define LM_TYPE_FLOCK 0x06
	36	#define LM_TYPE_PLOCK 0x07
	37	#define LM_TYPE_QUOTA 0x08
	38	#define LM_TYPE_JOURNAL 0x09
	39
	40	/*
	41	* lm_lock() states
	42	*
	43	* SHARED is compatible with SHARED, not with DEFERRED or EX.
	44	* DEFERRED is compatible with DEFERRED, not with SHARED or EX.
	45	*/
	46
	47	#define LM_ST_UNLOCKED 0
	48	#define LM_ST_EXCLUSIVE 1
	49	#define LM_ST_DEFERRED 2
	50	#define LM_ST_SHARED 3
	51
	52	/*
	53	* lm_lock() flags
	54	*
	55	* LM_FLAG_TRY
	56	* Don't wait to acquire the lock if it can't be granted immediately.
	57	*
	58	* LM_FLAG_TRY_1CB
	59	* Send one blocking callback if TRY is set and the lock is not granted.
	60	*
	61	* LM_FLAG_NOEXP
	62	* GFS sets this flag on lock requests it makes while doing journal recovery.
	63	* These special requests should not be blocked due to the recovery like
	64	* ordinary locks would be.
	65	*
	66	* LM_FLAG_ANY
	67	* A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
	68	* also be granted in SHARED. The preferred state is whichever is compatible
	69	* with other granted locks, or the specified state if no other locks exist.
	70	*
	71	* LM_FLAG_PRIORITY
	72	* Override fairness considerations. Suppose a lock is held in a shared state
	73	* and there is a pending request for the deferred state. A shared lock
	74	* request with the priority flag would be allowed to bypass the deferred
	75	* request and directly join the other shared lock. A shared lock request
	76	* without the priority flag might be forced to wait until the deferred
	77	* requested had acquired and released the lock.
	78	*/
79
b58bf407 BP	80	#define LM_FLAG_TRY 0x0001
	81	#define LM_FLAG_TRY_1CB 0x0002
	82	#define LM_FLAG_NOEXP 0x0004
	83	#define LM_FLAG_ANY 0x0008
	84	#define LM_FLAG_PRIORITY 0x0010
	85	#define GL_ASYNC 0x0040
	86	#define GL_EXACT 0x0080
	87	#define GL_SKIP 0x0100
	88	#define GL_NOCACHE 0x0400
f057f6cd SW	89
f057f6cd SW	90	/*
921169ca	91	* lm_async_cb return flags
f057f6cd SW	92	*
	93	* LM_OUT_ST_MASK
	94	* Masks the lower two bits of lock state in the returned value.
	95	*
	96	* LM_OUT_CANCELED
	97	* The lock request was canceled.
	98	*
f057f6cd SW	99	*/
	100
	101	#define LM_OUT_ST_MASK 0x00000003
	102	#define LM_OUT_CANCELED 0x00000008
921169ca	103	#define LM_OUT_ERROR 0x00000004
f057f6cd SW	104
	105	/*
	106	* lm_recovery_done() messages
	107	*/
	108
	109	#define LM_RD_GAVEUP 308
	110	#define LM_RD_SUCCESS 309
	111
	112	#define GLR_TRYFAILED 13
	113
7cf8dcd3 BP	114	#define GL_GLOCK_MAX_HOLD (long)(HZ / 5)
	115	#define GL_GLOCK_DFT_HOLD (long)(HZ / 5)
	116	#define GL_GLOCK_MIN_HOLD (long)(10)
	117	#define GL_GLOCK_HOLD_INCR (long)(HZ / 20)
	118	#define GL_GLOCK_HOLD_DECR (long)(HZ / 40)
	119
f057f6cd SW	120	struct lm_lockops {
f057f6cd SW	121	const char *lm_proto_name;
e0c2a9aa DT	122	int (lm_mount) (struct gfs2_sbd sdp, const char *table);
	123	void (lm_first_done) (struct gfs2_sbd sdp);
	124	void (lm_recovery_result) (struct gfs2_sbd sdp, unsigned int jid,
	125	unsigned int result);
	126	void (lm_unmount) (struct gfs2_sbd sdp);
f057f6cd	127	void (lm_withdraw) (struct gfs2_sbd sdp);
bc015cb8	128	void (lm_put_lock) (struct gfs2_glock gl);
921169ca SW	129	int (lm_lock) (struct gfs2_glock gl, unsigned int req_state,
921169ca SW	130	unsigned int flags);
f057f6cd SW	131	void (lm_cancel) (struct gfs2_glock gl);
	132	const match_table_t *lm_tokens;
	133	};
	134
b94a170e	135	extern struct workqueue_struct *gfs2_delete_workqueue;
7afd88d9	136	static inline struct gfs2_holder gfs2_glock_is_locked_by_me(struct gfs2_glock gl)
b3b94faa DT	137	{
b3b94faa DT	138	struct gfs2_holder *gh;
b1e058da	139	struct pid *pid;
b3b94faa DT	140
b3b94faa DT	141	/* Look in glock's list of holders for one with current task as owner */
f3dd1649	142	spin_lock(&gl->gl_lockref.lock);
b1e058da	143	pid = task_pid(current);
b3b94faa	144	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
6802e340 SW	145	if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
6802e340 SW	146	break;
7afd88d9 SW	147	if (gh->gh_owner_pid == pid)
7afd88d9 SW	148	goto out;
b3b94faa	149	}
7afd88d9 SW	150	gh = NULL;
7afd88d9 SW	151	out:
f3dd1649	152	spin_unlock(&gl->gl_lockref.lock);
b3b94faa	153
7afd88d9	154	return gh;
b3b94faa DT	155	}
	156
	157	static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
	158	{
50299965	159	return gl->gl_state == LM_ST_EXCLUSIVE;
b3b94faa DT	160	}
	161
	162	static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
	163	{
50299965	164	return gl->gl_state == LM_ST_DEFERRED;
b3b94faa DT	165	}
	166
	167	static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
	168	{
50299965	169	return gl->gl_state == LM_ST_SHARED;
b3b94faa DT	170	}
b3b94faa DT	171
009d8518 SW	172	static inline struct address_space gfs2_glock2aspace(struct gfs2_glock gl)
	173	{
	174	if (gl->gl_ops->go_flags & GLOF_ASPACE)
	175	return (struct address_space *)(gl + 1);
	176	return NULL;
	177	}
	178
8eae1ca0 SW	179	extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
	180	const struct gfs2_glock_operations *glops,
	181	int create, struct gfs2_glock **glp);
71c1b213	182	extern void gfs2_glock_hold(struct gfs2_glock *gl);
8eae1ca0	183	extern void gfs2_glock_put(struct gfs2_glock *gl);
71c1b213	184	extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
8eae1ca0	185	extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
b58bf407 BP	186	u16 flags, struct gfs2_holder *gh);
b58bf407 BP	187	extern void gfs2_holder_reinit(unsigned int state, u16 flags,
8eae1ca0 SW	188	struct gfs2_holder *gh);
	189	extern void gfs2_holder_uninit(struct gfs2_holder *gh);
	190	extern int gfs2_glock_nq(struct gfs2_holder *gh);
	191	extern int gfs2_glock_poll(struct gfs2_holder *gh);
	192	extern int gfs2_glock_wait(struct gfs2_holder *gh);
	193	extern void gfs2_glock_dq(struct gfs2_holder *gh);
	194	extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
	195	extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
	196	extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
	197	const struct gfs2_glock_operations *glops,
b58bf407	198	unsigned int state, u16 flags,
8eae1ca0 SW	199	struct gfs2_holder *gh);
	200	extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
	201	extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
27a2660f	202	extern void gfs2_dump_glock(struct seq_file seq, struct gfs2_glock gl);
8eae1ca0 SW	203	#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0)
8eae1ca0 SW	204	extern __printf(2, 3)
6802e340	205	void gfs2_print_dbg(struct seq_file seq, const char fmt, ...);
b3b94faa	206
d0dc80db	207	/**
33027af6	208	* gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
d0dc80db SW	209	* @gl: the glock
	210	* @state: the state we're requesting
	211	* @flags: the modifier flags
	212	* @gh: the holder structure
	213	*
	214	* Returns: 0, GLR_*, or errno
	215	*/
	216
	217	static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
b58bf407	218	unsigned int state, u16 flags,
d0dc80db SW	219	struct gfs2_holder *gh)
	220	{
	221	int error;
	222
	223	gfs2_holder_init(gl, state, flags, gh);
	224
	225	error = gfs2_glock_nq(gh);
	226	if (error)
	227	gfs2_holder_uninit(gh);
	228
	229	return error;
	230	}
	231
bc015cb8 SW	232	extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
bc015cb8 SW	233	extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
bc015cb8 SW	234	extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
	235	extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
	236	extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
29687a2a	237	extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
fc0e38da	238	extern void gfs2_glock_free(struct gfs2_glock *gl);
bc015cb8 SW	239
	240	extern int __init gfs2_glock_init(void);
	241	extern void gfs2_glock_exit(void);
	242
2abbf9a4	243	extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
bc015cb8	244	extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
2abbf9a4	245	extern void gfs2_register_debugfs(void);
bc015cb8	246	extern void gfs2_unregister_debugfs(void);
85d1da67	247
f057f6cd SW	248	extern const struct lm_lockops gfs2_dlm_ops;
f057f6cd SW	249
6df9f9a2 AG	250	static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
	251	{
	252	gh->gh_gl = NULL;
	253	}
	254
	255	static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
	256	{
	257	return gh->gh_gl;
	258	}
	259
df3d87bd BP	260	/**
	261	* glock_set_object - set the gl_object field of a glock
	262	* @gl: the glock
	263	* @object: the object
	264	*/
4fd1a579 AG	265	static inline void glock_set_object(struct gfs2_glock gl, void object)
	266	{
	267	spin_lock(&gl->gl_lockref.lock);
df3d87bd BP	268	if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
df3d87bd BP	269	gfs2_dump_glock(NULL, gl);
4fd1a579 AG	270	gl->gl_object = object;
	271	spin_unlock(&gl->gl_lockref.lock);
	272	}
	273
df3d87bd BP	274	/**
	275	* glock_clear_object - clear the gl_object field of a glock
	276	* @gl: the glock
	277	* @object: the object
	278	*
	279	* I'd love to similarly add this:
	280	* else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
	281	* gfs2_dump_glock(NULL, gl);
	282	* Unfortunately, that's not possible because as soon as gfs2_delete_inode
	283	* frees the block in the rgrp, another process can reassign it for an I_NEW
	284	* inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
	285	* That means gfs2_delete_inode may subsequently try to call this function
	286	* for a glock that's already pointing to a brand new inode. If we clear the
	287	* new inode's gl_object, we'll introduce metadata corruption. Function
	288	* gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
	289	* tries to clear gl_object, so it's more than just gfs2_delete_inode.
	290	*
	291	*/
	292	static inline void glock_clear_object(struct gfs2_glock gl, void object)
	293	{
	294	spin_lock(&gl->gl_lockref.lock);
	295	if (gl->gl_object == object)
	296	gl->gl_object = NULL;
	297	spin_unlock(&gl->gl_lockref.lock);
	298	}
	299
b3b94faa	300	#endif /* __GLOCK_DOT_H__ */