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