release/src/router/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
  27 typedef 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  */
  37 typedef struct e2fsck_struct *e2fsck_t;
  38
  39
  40 struct 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  */
  50 typedef 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
  96 extern int journal_blocks_per_page(struct inode *inode);
  97 extern 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  */
 121 typedef 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  */
 131 typedef 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
 185 struct kdev_s {
 186         e2fsck_t        k_ctx;
 187         int             k_dev;
 188 };
 189
 190 typedef struct kdev_s *kdev_t;
 191 typedef unsigned int tid_t;
 192
 193 struct 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
 216 typedef struct journal_s journal_t;
 217
 218 extern int         journal_recover    (journal_t *journal);
 219 extern int         journal_skip_recovery (journal_t *);
 220
 221 /* Primary revoke support */
 222 extern int         journal_init_revoke(journal_t *, int);
 223 extern void        journal_destroy_revoke_caches(void);
 224 extern int         journal_init_revoke_caches(void);
 225
 226 /* Recovery revoke support */
 227 extern int         journal_set_revoke(journal_t *, unsigned long, tid_t);
 228 extern int         journal_test_revoke(journal_t *, unsigned long, tid_t);
 229 extern void        journal_clear_revoke(journal_t *);
 230 extern void        journal_brelse_array(struct buffer_head *b[], int n);
 231
 232 extern void        journal_destroy_revoke(journal_t *);
 233
 234
 235 #endif