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    /*
     * (C) Copyright 2011 - 2012 Samsung Electronics
     * EXT4 filesystem implementation in Uboot by
     * Uma Shankar <uma.shankar@samsung.com>
     * Manjunatha C Achar <a.manjunatha@samsung.com>
     *
     * Journal data structures and headers for Journaling feature of ext4
     * have been referred from JBD2 (Journaling Block device 2)
     * implementation in Linux Kernel.
     *
     * Written by Stephen C. Tweedie <sct@redhat.com>
     *
     * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
    
     * SPDX-License-Identifier:	GPL-2.0+
    
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     */
    
    #ifndef __EXT4_JRNL__
    #define __EXT4_JRNL__
    
    #define EXT2_JOURNAL_INO		8	/* Journal inode */
    #define EXT2_JOURNAL_SUPERBLOCK	0	/* Journal  Superblock number */
    
    #define JBD2_FEATURE_COMPAT_CHECKSUM	0x00000001
    #define EXT3_JOURNAL_MAGIC_NUMBER	0xc03b3998U
    #define TRANSACTION_RUNNING		1
    #define TRANSACTION_COMPLETE		0
    #define EXT3_FEATURE_INCOMPAT_RECOVER	0x0004	/* Needs recovery */
    #define EXT3_JOURNAL_DESCRIPTOR_BLOCK	1
    #define EXT3_JOURNAL_COMMIT_BLOCK	2
    #define EXT3_JOURNAL_SUPERBLOCK_V1	3
    #define EXT3_JOURNAL_SUPERBLOCK_V2	4
    #define EXT3_JOURNAL_REVOKE_BLOCK	5
    #define EXT3_JOURNAL_FLAG_ESCAPE	1
    #define EXT3_JOURNAL_FLAG_SAME_UUID	2
    #define EXT3_JOURNAL_FLAG_DELETED	4
    #define EXT3_JOURNAL_FLAG_LAST_TAG	8
    
    /* Maximum entries in 1 journal transaction */
    #define MAX_JOURNAL_ENTRIES 100
    struct journal_log {
    	char *buf;
    	int blknr;
    };
    
    struct dirty_blocks {
    	char *buf;
    	int blknr;
    };
    
    /* Standard header for all descriptor blocks: */
    struct journal_header_t {
    	__u32 h_magic;
    	__u32 h_blocktype;
    	__u32 h_sequence;
    };
    
    /* The journal superblock.  All fields are in big-endian byte order. */
    struct journal_superblock_t {
    	/* 0x0000 */
    	struct journal_header_t s_header;
    
    	/* Static information describing the journal */
    	__u32 s_blocksize;	/* journal device blocksize */
    	__u32 s_maxlen;		/* total blocks in journal file */
    	__u32 s_first;		/* first block of log information */
    
    	/* Dynamic information describing the current state of the log */
    	__u32 s_sequence;	/* first commit ID expected in log */
    	__u32 s_start;		/* blocknr of start of log */
    
    	/* Error value, as set by journal_abort(). */
    	__s32 s_errno;
    
    	/* Remaining fields are only valid in a version-2 superblock */
    	__u32 s_feature_compat;	/* compatible feature set */
    	__u32 s_feature_incompat;	/* incompatible feature set */
    	__u32 s_feature_ro_compat;	/* readonly-compatible feature set */
    	/* 0x0030 */
    	__u8 s_uuid[16];	/* 128-bit uuid for journal */
    
    	/* 0x0040 */
    	__u32 s_nr_users;	/* Nr of filesystems sharing log */
    
    	__u32 s_dynsuper;	/* Blocknr of dynamic superblock copy */
    
    	/* 0x0048 */
    	__u32 s_max_transaction;	/* Limit of journal blocks per trans. */
    	__u32 s_max_trans_data;	/* Limit of data blocks per trans. */
    
    	/* 0x0050 */
    	__u32 s_padding[44];
    
    	/* 0x0100 */
    	__u8 s_users[16 * 48];	/* ids of all fs'es sharing the log */
    	/* 0x0400 */
    } ;
    
    struct ext3_journal_block_tag {
    	uint32_t block;
    	uint32_t flags;
    };
    
    struct journal_revoke_header_t {
    	struct journal_header_t r_header;
    	int r_count;		/* Count of bytes used in the block */
    };
    
    struct revoke_blk_list {
    	char *content;		/* revoke block itself */
    	struct revoke_blk_list *next;
    };
    
    extern struct ext2_data *ext4fs_root;
    
    int ext4fs_init_journal(void);
    int ext4fs_log_gdt(char *gd_table);
    int ext4fs_check_journal_state(int recovery_flag);
    int ext4fs_log_journal(char *journal_buffer, long int blknr);
    int ext4fs_put_metadata(char *metadata_buffer, long int blknr);
    void ext4fs_update_journal(void);
    void ext4fs_dump_metadata(void);
    void ext4fs_push_revoke_blk(char *buffer);
    void ext4fs_free_journal(void);
    void ext4fs_free_revoke_blks(void);
    #endif