1/*
2 *   Copyright (C) International Business Machines Corp., 2000-2002
3 *   Portions Copyright (C) Christoph Hellwig, 2001-2002
4 *
5 *   This program is free software;  you can redistribute it and/or modify
6 *   it under the terms of the GNU General Public License as published by
7 *   the Free Software Foundation; either version 2 of the License, or
8 *   (at your option) any later version.
9 *
10 *   This program is distributed in the hope that it will be useful,
11 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
12 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13 *   the GNU General Public License for more details.
14 *
15 *   You should have received a copy of the GNU General Public License
16 *   along with this program;  if not, write to the Free Software
17 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19#ifndef	_H_JFS_METAPAGE
20#define _H_JFS_METAPAGE
21
22#include <linux/pagemap.h>
23
24struct metapage {
25	/* Common logsyncblk prefix (see jfs_logmgr.h) */
26	u16 xflag;
27	u16 unused;
28	lid_t lid;
29	int lsn;
30	struct list_head synclist;
31	/* End of logsyncblk prefix */
32
33	unsigned long flag;	/* See Below */
34	unsigned long count;	/* Reference count */
35	void *data;		/* Data pointer */
36	sector_t index;		/* block address of page */
37	wait_queue_head_t wait;
38
39	/* implementation */
40	struct page *page;
41	unsigned int logical_size;
42
43	/* Journal management */
44	int clsn;
45	int nohomeok;
46	struct jfs_log *log;
47};
48
49/* metapage flag */
50#define META_locked	0
51#define META_dirty	2
52#define META_sync	3
53#define META_discard	4
54#define META_forcewrite	5
55#define META_io		6
56
57#define mark_metapage_dirty(mp) set_bit(META_dirty, &(mp)->flag)
58
59/* function prototypes */
60extern int metapage_init(void);
61extern void metapage_exit(void);
62extern struct metapage *__get_metapage(struct inode *inode,
63				  unsigned long lblock, unsigned int size,
64				  int absolute, unsigned long new);
65
66#define read_metapage(inode, lblock, size, absolute)\
67	 __get_metapage(inode, lblock, size, absolute, false)
68
69#define get_metapage(inode, lblock, size, absolute)\
70	 __get_metapage(inode, lblock, size, absolute, true)
71
72extern void release_metapage(struct metapage *);
73extern void grab_metapage(struct metapage *);
74extern void force_metapage(struct metapage *);
75
76/*
77 * hold_metapage and put_metapage are used in conjunction.  The page lock
78 * is not dropped between the two, so no other threads can get or release
79 * the metapage
80 */
81extern void hold_metapage(struct metapage *);
82extern void put_metapage(struct metapage *);
83
84static inline void write_metapage(struct metapage *mp)
85{
86	set_bit(META_dirty, &mp->flag);
87	release_metapage(mp);
88}
89
90static inline void flush_metapage(struct metapage *mp)
91{
92	set_bit(META_sync, &mp->flag);
93	write_metapage(mp);
94}
95
96static inline void discard_metapage(struct metapage *mp)
97{
98	clear_bit(META_dirty, &mp->flag);
99	set_bit(META_discard, &mp->flag);
100	release_metapage(mp);
101}
102
103static inline void metapage_nohomeok(struct metapage *mp)
104{
105	struct page *page = mp->page;
106	lock_page(page);
107	if (!mp->nohomeok++) {
108		mark_metapage_dirty(mp);
109		page_cache_get(page);
110		wait_on_page_writeback(page);
111	}
112	unlock_page(page);
113}
114
115/*
116 * This serializes access to mp->lsn when metapages are added to logsynclist
117 * without setting nohomeok.  i.e. updating imap & dmap
118 */
119static inline void metapage_wait_for_io(struct metapage *mp)
120{
121	if (test_bit(META_io, &mp->flag))
122		wait_on_page_writeback(mp->page);
123}
124
125/*
126 * This is called when already holding the metapage
127 */
128static inline void _metapage_homeok(struct metapage *mp)
129{
130	if (!--mp->nohomeok)
131		page_cache_release(mp->page);
132}
133
134static inline void metapage_homeok(struct metapage *mp)
135{
136	hold_metapage(mp);
137	_metapage_homeok(mp);
138	put_metapage(mp);
139}
140
141extern const struct address_space_operations jfs_metapage_aops;
142
143/*
144 * This routines invalidate all pages for an extent.
145 */
146extern void __invalidate_metapages(struct inode *, s64, int);
147#define invalidate_pxd_metapages(ip, pxd) \
148	__invalidate_metapages((ip), addressPXD(&(pxd)), lengthPXD(&(pxd)))
149#define invalidate_dxd_metapages(ip, dxd) \
150	__invalidate_metapages((ip), addressDXD(&(dxd)), lengthDXD(&(dxd)))
151#define invalidate_xad_metapages(ip, xad) \
152	__invalidate_metapages((ip), addressXAD(&(xad)), lengthXAD(&(xad)))
153
154#endif				/* _H_JFS_METAPAGE */
155