fs/reiser4/wander.h

   1 /* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
   2
   3 #if !defined (__FS_REISER4_WANDER_H__)
   4 #define __FS_REISER4_WANDER_H__
   5
   6 #include "dformat.h"
   7
   8 #include <linux/fs.h>           /* for struct super_block  */
   9
  10 /* REISER4 JOURNAL ON-DISK DATA STRUCTURES   */
  11
  12 #define TX_HEADER_MAGIC  "TxMagic4"
  13 #define WANDER_RECORD_MAGIC "LogMagc4"
  14
  15 #define TX_HEADER_MAGIC_SIZE  (8)
  16 #define WANDER_RECORD_MAGIC_SIZE (8)
  17
  18 /* journal header block format */
  19 struct journal_header {
  20         /* last written transaction head location */
  21         d64 last_committed_tx;
  22 };
  23
  24 typedef struct journal_location {
  25         reiser4_block_nr footer;
  26         reiser4_block_nr header;
  27 } journal_location;
  28
  29 /* The wander.c head comment describes usage and semantic of all these structures */
  30 /* journal footer block format */
  31 struct journal_footer {
  32         /* last flushed transaction location. */
  33         /* This block number is no more valid after the transaction it points
  34            to gets flushed, this number is used only at journal replaying time
  35            for detection of the end of on-disk list of committed transactions
  36            which were not flushed completely */
  37         d64 last_flushed_tx;
  38
  39         /* free block counter is written in journal footer at transaction
  40            flushing , not in super block because free blocks counter is logged
  41            by another way than super block fields (root pointer, for
  42            example). */
  43         d64 free_blocks;
  44
  45         /* number of used OIDs and maximal used OID are logged separately from
  46            super block */
  47         d64 nr_files;
  48         d64 next_oid;
  49 };
  50
  51 /* Each wander record (except the first one) has unified format with wander
  52    record header followed by an array of log entries */
  53 struct wander_record_header {
  54         /* when there is no predefined location for wander records, this magic
  55            string should help reiser4fsck. */
  56         char magic[WANDER_RECORD_MAGIC_SIZE];
  57
  58         /* transaction id */
  59         d64 id;
  60
  61         /* total number of wander records in current transaction  */
  62         d32 total;
  63
  64         /* this block number in transaction */
  65         d32 serial;
  66
  67         /* number of previous block in commit */
  68         d64 next_block;
  69 };
  70
  71 /* The first wander record (transaction head) of written transaction has the
  72    special format */
  73 struct tx_header {
  74         /* magic string makes first block in transaction different from other
  75            logged blocks, it should help fsck. */
  76         char magic[TX_HEADER_MAGIC_SIZE];
  77
  78         /* transaction id */
  79         d64 id;
  80
  81         /* total number of records (including this first tx head) in the
  82            transaction */
  83         d32 total;
  84
  85         /* align next field to 8-byte boundary; this field always is zero */
  86         d32 padding;
  87
  88         /* block number of previous transaction head */
  89         d64 prev_tx;
  90
  91         /* next wander record location */
  92         d64 next_block;
  93
  94         /* committed versions of free blocks counter */
  95         d64 free_blocks;
  96
  97         /* number of used OIDs (nr_files) and maximal used OID are logged
  98            separately from super block */
  99         d64 nr_files;
 100         d64 next_oid;
 101 };
 102
 103 /* A transaction gets written to disk as a set of wander records (each wander
 104    record size is fs block) */
 105
 106 /* As it was told above a wander The rest of wander record is filled by these log entries, unused space filled
 107    by zeroes */
 108 struct wander_entry {
 109         d64 original;           /* block original location */
 110         d64 wandered;           /* block wandered location */
 111 };
 112
 113 /* REISER4 JOURNAL WRITER FUNCTIONS   */
 114
 115 extern int reiser4_write_logs(long *);
 116 extern int reiser4_journal_replay(struct super_block *);
 117 extern int reiser4_journal_recover_sb_data(struct super_block *);
 118
 119 extern int reiser4_init_journal_info(struct super_block *);
 120 extern void reiser4_done_journal_info(struct super_block *);
 121
 122 extern int write_jnode_list(struct list_head *, flush_queue_t *, long *, int);
 123
 124 #endif                          /* __FS_REISER4_WANDER_H__ */
 125
 126 /* Make Linus happy.
 127    Local variables:
 128    c-indentation-style: "K&R"
 129    mode-name: "LC"
 130    c-basic-offset: 8
 131    tab-width: 8
 132    fill-column: 80
 133    scroll-step: 1
 134    End:
 135 */