fs/ext4/ext4_journal.h

   1 /*
   2  * (C) Copyright 2011 - 2012 Samsung Electronics
   3  * EXT4 filesystem implementation in Uboot by
   4  * Uma Shankar <uma.shankar@samsung.com>
   5  * Manjunatha C Achar <a.manjunatha@samsung.com>
   6  *
   7  * Journal data structures and headers for Journaling feature of ext4
   8  * have been referred from JBD2 (Journaling Block device 2)
   9  * implementation in Linux Kernel.
  10  *
  11  * Written by Stephen C. Tweedie <sct@redhat.com>
  12  *
  13  * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
  14  * SPDX-License-Identifier:     GPL-2.0+
  15  */
  16
  17 #ifndef __EXT4_JRNL__
  18 #define __EXT4_JRNL__
  19
  20 #define EXT2_JOURNAL_INO                8       /* Journal inode */
  21 #define EXT2_JOURNAL_SUPERBLOCK 0       /* Journal  Superblock number */
  22
  23 #define JBD2_FEATURE_COMPAT_CHECKSUM    0x00000001
  24 #define EXT3_JOURNAL_MAGIC_NUMBER       0xc03b3998U
  25 #define TRANSACTION_RUNNING             1
  26 #define TRANSACTION_COMPLETE            0
  27 #define EXT3_FEATURE_INCOMPAT_RECOVER   0x0004  /* Needs recovery */
  28 #define EXT3_JOURNAL_DESCRIPTOR_BLOCK   1
  29 #define EXT3_JOURNAL_COMMIT_BLOCK       2
  30 #define EXT3_JOURNAL_SUPERBLOCK_V1      3
  31 #define EXT3_JOURNAL_SUPERBLOCK_V2      4
  32 #define EXT3_JOURNAL_REVOKE_BLOCK       5
  33 #define EXT3_JOURNAL_FLAG_ESCAPE        1
  34 #define EXT3_JOURNAL_FLAG_SAME_UUID     2
  35 #define EXT3_JOURNAL_FLAG_DELETED       4
  36 #define EXT3_JOURNAL_FLAG_LAST_TAG      8
  37
  38 /* Maximum entries in 1 journal transaction */
  39 #define MAX_JOURNAL_ENTRIES 100
  40 struct journal_log {
  41         char *buf;
  42         int blknr;
  43 };
  44
  45 struct dirty_blocks {
  46         char *buf;
  47         int blknr;
  48 };
  49
  50 /* Standard header for all descriptor blocks: */
  51 struct journal_header_t {
  52         __be32 h_magic;
  53         __be32 h_blocktype;
  54         __be32 h_sequence;
  55 };
  56
  57 /* The journal superblock.  All fields are in big-endian byte order. */
  58 struct journal_superblock_t {
  59         /* 0x0000 */
  60         struct journal_header_t s_header;
  61
  62         /* Static information describing the journal */
  63         __be32 s_blocksize;     /* journal device blocksize */
  64         __be32 s_maxlen;                /* total blocks in journal file */
  65         __be32 s_first;         /* first block of log information */
  66
  67         /* Dynamic information describing the current state of the log */
  68         __be32 s_sequence;      /* first commit ID expected in log */
  69         __be32 s_start;         /* blocknr of start of log */
  70
  71         /* Error value, as set by journal_abort(). */
  72         __be32 s_errno;
  73
  74         /* Remaining fields are only valid in a version-2 superblock */
  75         __be32 s_feature_compat;        /* compatible feature set */
  76         __be32 s_feature_incompat;      /* incompatible feature set */
  77         __be32 s_feature_ro_compat;     /* readonly-compatible feature set */
  78         /* 0x0030 */
  79         __u8 s_uuid[16];        /* 128-bit uuid for journal */
  80
  81         /* 0x0040 */
  82         __be32 s_nr_users;      /* Nr of filesystems sharing log */
  83
  84         __be32 s_dynsuper;      /* Blocknr of dynamic superblock copy */
  85
  86         /* 0x0048 */
  87         __be32 s_max_transaction;       /* Limit of journal blocks per trans. */
  88         __be32 s_max_trans_data;        /* Limit of data blocks per trans. */
  89
  90         /* 0x0050 */
  91         __be32 s_padding[44];
  92
  93         /* 0x0100 */
  94         __u8 s_users[16 * 48];  /* ids of all fs'es sharing the log */
  95         /* 0x0400 */
  96 } ;
  97
  98 struct ext3_journal_block_tag {
  99         __be32 block;
 100         __be32 flags;
 101 };
 102
 103 struct journal_revoke_header_t {
 104         struct journal_header_t r_header;
 105         __be32 r_count;         /* Count of bytes used in the block */
 106 };
 107
 108 struct revoke_blk_list {
 109         char *content;          /* revoke block itself */
 110         struct revoke_blk_list *next;
 111 };
 112
 113 extern struct ext2_data *ext4fs_root;
 114
 115 int ext4fs_init_journal(void);
 116 int ext4fs_log_gdt(char *gd_table);
 117 int ext4fs_check_journal_state(int recovery_flag);
 118 int ext4fs_log_journal(char *journal_buffer, uint32_t blknr);
 119 int ext4fs_put_metadata(char *metadata_buffer, uint32_t blknr);
 120 void ext4fs_update_journal(void);
 121 void ext4fs_dump_metadata(void);
 122 void ext4fs_push_revoke_blk(char *buffer);
 123 void ext4fs_free_journal(void);
 124 void ext4fs_free_revoke_blks(void);
 125 #endif