fs/jfs/jfs_metapage.h

   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         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 */
  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 conjuction.  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
  85 static inline void write_metapage(struct metapage *mp)
  86 {
  87         set_bit(META_dirty, &mp->flag);
  88         release_metapage(mp);
  89 }
  90
  91 static inline void flush_metapage(struct metapage *mp)
  92 {
  93         set_bit(META_sync, &mp->flag);
  94         write_metapage(mp);
  95 }
  96
  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
 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                 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  */
 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  */
 129 static inline void _metapage_homeok(struct metapage *mp)
 130 {
 131         if (!--mp->nohomeok)
 132                 page_cache_release(mp->page);
 133 }
 134
 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 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 */