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/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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* header file extracted from linux/include/linux/jbd2.h
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* Originally written by Stephen C. Tweedie <sct@redhat.com>
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* Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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* Definitions for transaction data structures for the buffer cache
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* filesystem journaling support.
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* Internal structures used by the logging mechanism:
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#define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
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* Descriptor block types:
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#define JBD2_DESCRIPTOR_BLOCK 1
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#define JBD2_COMMIT_BLOCK 2
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#define JBD2_SUPERBLOCK_V1 3
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#define JBD2_SUPERBLOCK_V2 4
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#define JBD2_REVOKE_BLOCK 5
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* Standard header for all descriptor blocks:
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typedef struct journal_header_s
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#define JBD2_CRC32_CHKSUM 1
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#define JBD2_MD5_CHKSUM 2
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#define JBD2_SHA2_CHKSUM 3
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#define JBD2_CRC32_CHKSUM_SIZE 4
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#define JBD2_CHECKSUM_BYTES (32 / sizeof(uint32_t))
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* Commit block header for storing transactional checksums:
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struct commit_header {
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unsigned char h_chksum_type;
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unsigned char h_chksum_size;
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unsigned char h_padding[2];
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__be32 h_chksum[JBD2_CHECKSUM_BYTES];
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* The block tag: used to describe a single buffer in the journal.
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* t_blocknr_high is only used if INCOMPAT_64BIT is set, so this
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* raw struct shouldn't be used for pointer math or sizeof() - use
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* journal_tag_bytes(journal) instead to compute this.
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typedef struct journal_block_tag_s
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__be32 t_blocknr; /* The on-disk block number */
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__be32 t_flags; /* See below */
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__be32 t_blocknr_high; /* most-significant high 32bits. */
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} journal_block_tag_t;
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#define JBD2_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high))
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#define JBD2_TAG_SIZE64 (sizeof(journal_block_tag_t))
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* The revoke descriptor: used on disk to describe a series of blocks to
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* be revoked from the log
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typedef struct journal_revoke_header_s
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journal_header_t r_header;
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int r_count; /* Count of bytes used in the block */
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} journal_revoke_header_t;
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/* Definitions for the journal tag flags word: */
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#define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */
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#define JBD2_FLAG_SAME_UUID 2 /* block has same uuid as previous */
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#define JBD2_FLAG_DELETED 4 /* block deleted by this transaction */
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#define JBD2_FLAG_LAST_TAG 8 /* last tag in this descriptor block */
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* The journal superblock. All fields are in big-endian byte order.
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typedef struct journal_superblock_s
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journal_header_t s_header;
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/* Static information describing the journal */
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__be32 s_blocksize; /* journal device blocksize */
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__be32 s_maxlen; /* total blocks in journal file */
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__be32 s_first; /* first block of log information */
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/* Dynamic information describing the current state of the log */
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__be32 s_sequence; /* first commit ID expected in log */
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__be32 s_start; /* blocknr of start of log */
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/* Error value, as set by jbd2_journal_abort(). */
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/* Remaining fields are only valid in a version-2 superblock */
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__be32 s_feature_compat; /* compatible feature set */
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__be32 s_feature_incompat; /* incompatible feature set */
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__be32 s_feature_ro_compat; /* readonly-compatible feature set */
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__u8 s_uuid[16]; /* 128-bit uuid for journal */
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__be32 s_nr_users; /* Nr of filesystems sharing log */
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__be32 s_dynsuper; /* Blocknr of dynamic superblock copy*/
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__be32 s_max_transaction; /* Limit of journal blocks per trans.*/
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__be32 s_max_trans_data; /* Limit of data blocks per trans. */
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__be32 s_padding[44];
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__u8 s_users[16*48]; /* ids of all fs'es sharing the log */
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} journal_superblock_t;
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#define JBD2_HAS_COMPAT_FEATURE(jsb,mask) \
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(((jsb)->s_header.h_blocktype == JBD2_SUPERBLOCK_V2) && \
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((jsb)->s_feature_compat & mask))
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#define JBD2_HAS_RO_COMPAT_FEATURE(jsb,mask) \
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(((jsb)->s_header.h_blocktype == JBD2_SUPERBLOCK_V2) && \
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((jsb)->s_feature_ro_compat & mask))
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#define JBD2_HAS_INCOMPAT_FEATURE(jsb,mask) \
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(((jsb)->s_header.h_blocktype == JBD2_SUPERBLOCK_V2) && \
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((jsb)->s_feature_incompat & mask))
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#define JBD2_FEATURE_COMPAT_CHECKSUM 0x00000001
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#define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001
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#define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002
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#define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004
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/* Features known to this kernel version: */
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#define JBD2_KNOWN_COMPAT_FEATURES 0
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#define JBD2_KNOWN_ROCOMPAT_FEATURES 0
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#define JBD2_KNOWN_INCOMPAT_FEATURES (JBD2_FEATURE_INCOMPAT_REVOKE \
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| JBD2_FEATURE_INCOMPAT_64BIT)
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#endif /* _JBD2_H_ */
added
removed
include/ocfs2/jbd2.h
