LXR busybox/e2fsprogs/old_e2fsprogs/ext2fs/kernel-jbd.h

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * linux/include/linux/jbd.h
   4 *
   5 * Written by Stephen C. Tweedie <sct@redhat.com>
   6 *
   7 * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
   8 *
   9 * This file is part of the Linux kernel and is made available under
  10 * the terms of the GNU General Public License, version 2, or at your
  11 * option, any later version, incorporated herein by reference.
  12 *
  13 * Definitions for transaction data structures for the buffer cache
  14 * filesystem journaling support.
  15 */
  16#ifndef LINUX_JBD_H
  17#define LINUX_JBD_H 1
  18
  19#include <sys/types.h>
  20#include <linux/types.h>
  21#include "ext2fs.h"
  22
  23/*
  24 * Standard header for all descriptor blocks:
  25 */
  26
  27typedef struct journal_header_s
  28{
  29        __u32           h_magic;
  30        __u32           h_blocktype;
  31        __u32           h_sequence;
  32} journal_header_t;
  33
  34/*
  35 * This is the global e2fsck structure.
  36 */
  37typedef struct e2fsck_struct *e2fsck_t;
  38
  39
  40struct inode {
  41        e2fsck_t        i_ctx;
  42        ext2_ino_t      i_ino;
  43        struct ext2_inode i_ext2;
  44};
  45
  46
  47/*
  48 * The journal superblock.  All fields are in big-endian byte order.
  49 */
  50typedef struct journal_superblock_s
  51{
  52/* 0x0000 */
  53        journal_header_t s_header;
  54
  55/* 0x000C */
  56        /* Static information describing the journal */
  57        __u32   s_blocksize;            /* journal device blocksize */
  58        __u32   s_maxlen;               /* total blocks in journal file */
  59        __u32   s_first;                /* first block of log information */
  60
  61/* 0x0018 */
  62        /* Dynamic information describing the current state of the log */
  63        __u32   s_sequence;             /* first commit ID expected in log */
  64        __u32   s_start;                /* blocknr of start of log */
  65
  66/* 0x0020 */
  67        /* Error value, as set by journal_abort(). */
  68        __s32   s_errno;
  69
  70/* 0x0024 */
  71        /* Remaining fields are only valid in a version-2 superblock */
  72        __u32   s_feature_compat;       /* compatible feature set */
  73        __u32   s_feature_incompat;     /* incompatible feature set */
  74        __u32   s_feature_ro_compat;    /* readonly-compatible feature set */
  75/* 0x0030 */
  76        __u8    s_uuid[16];             /* 128-bit uuid for journal */
  77
  78/* 0x0040 */
  79        __u32   s_nr_users;             /* Nr of filesystems sharing log */
  80
  81        __u32   s_dynsuper;             /* Blocknr of dynamic superblock copy*/
  82
  83/* 0x0048 */
  84        __u32   s_max_transaction;      /* Limit of journal blocks per trans.*/
  85        __u32   s_max_trans_data;       /* Limit of data blocks per trans. */
  86
  87/* 0x0050 */
  88        __u32   s_padding[44];
  89
  90/* 0x0100 */
  91        __u8    s_users[16*48];         /* ids of all fs'es sharing the log */
  92/* 0x0400 */
  93} journal_superblock_t;
  94
  95
  96extern int journal_blocks_per_page(struct inode *inode);
  97extern int jbd_blocks_per_page(struct inode *inode);
  98
  99#define JFS_MIN_JOURNAL_BLOCKS 1024
 100
 101
 102/*
 103 * Internal structures used by the logging mechanism:
 104 */
 105
 106#define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
 107
 108/*
 109 * Descriptor block types:
 110 */
 111
 112#define JFS_DESCRIPTOR_BLOCK    1
 113#define JFS_COMMIT_BLOCK        2
 114#define JFS_SUPERBLOCK_V1       3
 115#define JFS_SUPERBLOCK_V2       4
 116#define JFS_REVOKE_BLOCK        5
 117
 118/*
 119 * The block tag: used to describe a single buffer in the journal
 120 */
 121typedef struct journal_block_tag_s
 122{
 123        __u32           t_blocknr;      /* The on-disk block number */
 124        __u32           t_flags;        /* See below */
 125} journal_block_tag_t;
 126
 127/*
 128 * The revoke descriptor: used on disk to describe a series of blocks to
 129 * be revoked from the log
 130 */
 131typedef struct journal_revoke_header_s
 132{
 133        journal_header_t r_header;
 134        int              r_count;       /* Count of bytes used in the block */
 135} journal_revoke_header_t;
 136
 137
 138/* Definitions for the journal tag flags word: */
 139#define JFS_FLAG_ESCAPE         1       /* on-disk block is escaped */
 140#define JFS_FLAG_SAME_UUID      2       /* block has same uuid as previous */
 141#define JFS_FLAG_DELETED        4       /* block deleted by this transaction */
 142#define JFS_FLAG_LAST_TAG       8       /* last tag in this descriptor block */
 143
 144
 145
 146
 147#define JFS_HAS_COMPAT_FEATURE(j,mask)                                  \
 148        ((j)->j_format_version >= 2 &&                                  \
 149         ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
 150#define JFS_HAS_RO_COMPAT_FEATURE(j,mask)                               \
 151        ((j)->j_format_version >= 2 &&                                  \
 152         ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
 153#define JFS_HAS_INCOMPAT_FEATURE(j,mask)                                \
 154        ((j)->j_format_version >= 2 &&                                  \
 155         ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 156
 157#define JFS_FEATURE_INCOMPAT_REVOKE     0x00000001
 158
 159/* Features known to this kernel version: */
 160#define JFS_KNOWN_COMPAT_FEATURES       0
 161#define JFS_KNOWN_ROCOMPAT_FEATURES     0
 162#define JFS_KNOWN_INCOMPAT_FEATURES     JFS_FEATURE_INCOMPAT_REVOKE
 163
 164/* Comparison functions for transaction IDs: perform comparisons using
 165 * modulo arithmetic so that they work over sequence number wraps. */
 166
 167
 168/*
 169 * Definitions which augment the buffer_head layer
 170 */
 171
 172/* journaling buffer types */
 173#define BJ_None         0       /* Not journaled */
 174#define BJ_SyncData     1       /* Normal data: flush before commit */
 175#define BJ_AsyncData    2       /* writepage data: wait on it before commit */
 176#define BJ_Metadata     3       /* Normal journaled metadata */
 177#define BJ_Forget       4       /* Buffer superceded by this transaction */
 178#define BJ_IO           5       /* Buffer is for temporary IO use */
 179#define BJ_Shadow       6       /* Buffer contents being shadowed to the log */
 180#define BJ_LogCtl       7       /* Buffer contains log descriptors */
 181#define BJ_Reserved     8       /* Buffer is reserved for access by journal */
 182#define BJ_Types        9
 183
 184
 185struct kdev_s {
 186        e2fsck_t        k_ctx;
 187        int             k_dev;
 188};
 189
 190typedef struct kdev_s *kdev_t;
 191typedef unsigned int tid_t;
 192
 193struct journal_s
 194{
 195        unsigned long           j_flags;
 196        int                     j_errno;
 197        struct buffer_head *    j_sb_buffer;
 198        struct journal_superblock_s *j_superblock;
 199        int                     j_format_version;
 200        unsigned long           j_head;
 201        unsigned long           j_tail;
 202        unsigned long           j_free;
 203        unsigned long           j_first, j_last;
 204        kdev_t                  j_dev;
 205        kdev_t                  j_fs_dev;
 206        int                     j_blocksize;
 207        unsigned int            j_blk_offset;
 208        unsigned int            j_maxlen;
 209        struct inode *          j_inode;
 210        tid_t                   j_tail_sequence;
 211        tid_t                   j_transaction_sequence;
 212        __u8                    j_uuid[16];
 213        struct jbd_revoke_table_s *j_revoke;
 214};
 215
 216typedef struct journal_s journal_t;
 217
 218extern int         journal_recover    (journal_t *journal);
 219extern int         journal_skip_recovery (journal_t *);
 220
 221/* Primary revoke support */
 222extern int         journal_init_revoke(journal_t *, int);
 223extern void        journal_destroy_revoke_caches(void);
 224extern int         journal_init_revoke_caches(void);
 225
 226/* Recovery revoke support */
 227extern int         journal_set_revoke(journal_t *, unsigned long, tid_t);
 228extern int         journal_test_revoke(journal_t *, unsigned long, tid_t);
 229extern void        journal_clear_revoke(journal_t *);
 230extern void        journal_brelse_array(struct buffer_head *b[], int n);
 231
 232extern void        journal_destroy_revoke(journal_t *);
 233
 234
 235#endif
 236