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/*
* include/linux/journal-head.h
*
* buffer_head fields for JBD
*
* 27 May 2001 ANdrew Morton <andrewm@uow.edu.au>
* Created - pulled out of fs.h
*/
#ifndef JOURNAL_HEAD_H_INCLUDED
#define JOURNAL_HEAD_H_INCLUDED
typedef unsigned int tid_t; /* Unique transaction ID */
typedef struct transaction_s transaction_t; /* Compound transaction type */
struct buffer_head;
struct journal_head {
#ifndef CONFIG_JBD_UNIFIED_BUFFERS
/* Points back to our buffer_head. */
struct buffer_head *b_bh;
#endif
/* Reference count - see description in journal.c */
int b_jcount;
/* Journaling list for this buffer */
unsigned b_jlist;
/* Copy of the buffer data frozen for writing to the log. */
char * b_frozen_data;
/* Pointer to a saved copy of the buffer containing no
uncommitted deallocation references, so that allocations can
avoid overwriting uncommitted deletes. */
char * b_committed_data;
/* Pointer to the compound transaction which owns this buffer's
metadata: either the running transaction or the committing
transaction (if there is one). Only applies to buffers on a
transaction's data or metadata journaling list. */
/* Protected by journal_datalist_lock */
transaction_t * b_transaction;
/* Pointer to the running compound transaction which is
currently modifying the buffer's metadata, if there was
already a transaction committing it when the new transaction
touched it. */
transaction_t * b_next_transaction;
/* Doubly-linked list of buffers on a transaction's data,
metadata or forget queue. */
/* Protected by journal_datalist_lock */
struct journal_head *b_tnext, *b_tprev;
/*
* Pointer to the compound transaction against which this buffer
* is checkpointed. Only dirty buffers can be checkpointed.
*/
/* Protected by journal_datalist_lock */
transaction_t * b_cp_transaction;
/*
* Doubly-linked list of buffers still remaining to be flushed
* before an old transaction can be checkpointed.
*/
/* Protected by journal_datalist_lock */
struct journal_head *b_cpnext, *b_cpprev;
};
#endif /* JOURNAL_HEAD_H_INCLUDED */
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