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 
24 struct 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 	struct super_block *sb;
42 	unsigned int logical_size;
43 
44 	/* Journal management */
45 	int clsn;
46 	int nohomeok;
47 	struct jfs_log *log;
48 };
49 
50 /* metapage flag */
51 #define META_locked	0
52 #define META_dirty	2
53 #define META_sync	3
54 #define META_discard	4
55 #define META_forcewrite	5
56 #define META_io		6
57 
58 #define mark_metapage_dirty(mp) set_bit(META_dirty, &(mp)->flag)
59 
60 /* function prototypes */
61 extern int metapage_init(void);
62 extern void metapage_exit(void);
63 extern struct metapage *__get_metapage(struct inode *inode,
64 				  unsigned long lblock, unsigned int size,
65 				  int absolute, unsigned long new);
66 
67 #define read_metapage(inode, lblock, size, absolute)\
68 	 __get_metapage(inode, lblock, size, absolute, false)
69 
70 #define get_metapage(inode, lblock, size, absolute)\
71 	 __get_metapage(inode, lblock, size, absolute, true)
72 
73 extern void release_metapage(struct metapage *);
74 extern void grab_metapage(struct metapage *);
75 extern void force_metapage(struct metapage *);
76 
77 /*
78  * hold_metapage and put_metapage are used in conjunction.  The page lock
79  * is not dropped between the two, so no other threads can get or release
80  * the metapage
81  */
82 extern void hold_metapage(struct metapage *);
83 extern void put_metapage(struct metapage *);
84 
write_metapage(struct metapage * mp)85 static inline void write_metapage(struct metapage *mp)
86 {
87 	set_bit(META_dirty, &mp->flag);
88 	release_metapage(mp);
89 }
90 
flush_metapage(struct metapage * mp)91 static inline void flush_metapage(struct metapage *mp)
92 {
93 	set_bit(META_sync, &mp->flag);
94 	write_metapage(mp);
95 }
96 
discard_metapage(struct metapage * mp)97 static inline void discard_metapage(struct metapage *mp)
98 {
99 	clear_bit(META_dirty, &mp->flag);
100 	set_bit(META_discard, &mp->flag);
101 	release_metapage(mp);
102 }
103 
metapage_nohomeok(struct metapage * mp)104 static inline void metapage_nohomeok(struct metapage *mp)
105 {
106 	struct page *page = mp->page;
107 	lock_page(page);
108 	if (!mp->nohomeok++) {
109 		mark_metapage_dirty(mp);
110 		get_page(page);
111 		wait_on_page_writeback(page);
112 	}
113 	unlock_page(page);
114 }
115 
116 /*
117  * This serializes access to mp->lsn when metapages are added to logsynclist
118  * without setting nohomeok.  i.e. updating imap & dmap
119  */
metapage_wait_for_io(struct metapage * mp)120 static inline void metapage_wait_for_io(struct metapage *mp)
121 {
122 	if (test_bit(META_io, &mp->flag))
123 		wait_on_page_writeback(mp->page);
124 }
125 
126 /*
127  * This is called when already holding the metapage
128  */
_metapage_homeok(struct metapage * mp)129 static inline void _metapage_homeok(struct metapage *mp)
130 {
131 	if (!--mp->nohomeok)
132 		put_page(mp->page);
133 }
134 
metapage_homeok(struct metapage * mp)135 static inline void metapage_homeok(struct metapage *mp)
136 {
137 	hold_metapage(mp);
138 	_metapage_homeok(mp);
139 	put_metapage(mp);
140 }
141 
142 extern const struct address_space_operations jfs_metapage_aops;
143 
144 /*
145  * This routines invalidate all pages for an extent.
146  */
147 extern void __invalidate_metapages(struct inode *, s64, int);
148 #define invalidate_pxd_metapages(ip, pxd) \
149 	__invalidate_metapages((ip), addressPXD(&(pxd)), lengthPXD(&(pxd)))
150 #define invalidate_dxd_metapages(ip, dxd) \
151 	__invalidate_metapages((ip), addressDXD(&(dxd)), lengthDXD(&(dxd)))
152 #define invalidate_xad_metapages(ip, xad) \
153 	__invalidate_metapages((ip), addressXAD(&(xad)), lengthXAD(&(xad)))
154 
155 #endif				/* _H_JFS_METAPAGE */
156