linux/fs/jfs/jfs_metapage.h
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   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_free       1
  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 */
  61extern int metapage_init(void);
  62extern void metapage_exit(void);
  63extern 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
  73extern void release_metapage(struct metapage *);
  74extern void grab_metapage(struct metapage *);
  75extern 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 */
  82extern void hold_metapage(struct metapage *);
  83extern void put_metapage(struct metapage *);
  84
  85static inline void write_metapage(struct metapage *mp)
  86{
  87        set_bit(META_dirty, &mp->flag);
  88        release_metapage(mp);
  89}
  90
  91static inline void flush_metapage(struct metapage *mp)
  92{
  93        set_bit(META_sync, &mp->flag);
  94        write_metapage(mp);
  95}
  96
  97static 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
 104static 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                page_cache_get(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 */
 120static 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 */
 129static inline void _metapage_homeok(struct metapage *mp)
 130{
 131        if (!--mp->nohomeok)
 132                page_cache_release(mp->page);
 133}
 134
 135static inline void metapage_homeok(struct metapage *mp)
 136{
 137        hold_metapage(mp);
 138        _metapage_homeok(mp);
 139        put_metapage(mp);
 140}
 141
 142extern const struct address_space_operations jfs_metapage_aops;
 143
 144/*
 145 * This routines invalidate all pages for an extent.
 146 */
 147extern 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
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