/* * include/linux/journal-head.h * * buffer_head fields for JBD * * 27 May 2001 Andrew Morton <akpm@digeo.com> * 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 { /* * Points back to our buffer_head. [jbd_lock_bh_journal_head()] */ struct buffer_head *b_bh; /* * Reference count - see description in journal.c * [jbd_lock_bh_journal_head()] */ int b_jcount; /* * Journalling list for this buffer [jbd_lock_bh_state()] */ unsigned b_jlist; /* * This flag signals the buffer has been modified by * the currently running transaction * [jbd_lock_bh_state()] */ unsigned b_modified; /* * Copy of the buffer data frozen for writing to the log. * [jbd_lock_bh_state()] */ 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. [jbd_lock_bh_state()] */ 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. * [j_list_lock] [jbd_lock_bh_state()] */ 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. * [t_list_lock] [jbd_lock_bh_state()] */ transaction_t *b_next_transaction; /* * Doubly-linked list of buffers on a transaction's data, metadata or * forget queue. [t_list_lock] [jbd_lock_bh_state()] */ struct journal_head *b_tnext, *b_tprev; /* * Pointer to the compound transaction against which this buffer * is checkpointed. Only dirty buffers can be checkpointed. * [j_list_lock] */ transaction_t *b_cp_transaction; /* * Doubly-linked list of buffers still remaining to be flushed * before an old transaction can be checkpointed. * [j_list_lock] */ struct journal_head *b_cpnext, *b_cpprev; }; #endif /* JOURNAL_HEAD_H_INCLUDED */