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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115/* SPDX-License-Identifier: GPL-2.0 *//* * include/linux/journal-head.h * * buffer_head fields for JBD * * 27 May 2001 Andrew Morton * Created - pulled out of fs.h */
#ifndef JOURNAL_HEAD_H_INCLUDED#define JOURNAL_HEAD_H_INCLUDED
#include <linux/spinlock.h>
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;
/* * Protect the buffer head state */ spinlock_t b_state_lock;
/* * Reference count - see description in journal.c * [jbd_lock_bh_journal_head()] */ int b_jcount;
/* * Journalling list for this buffer [b_state_lock] * NOTE: We *cannot* combine this with b_modified into a bitfield * as gcc would then (which the C standard allows but which is * very unuseful) make 64-bit accesses to the bitfield and clobber * b_jcount if its update races with bitfield modification. */ unsigned b_jlist;
/* * This flag signals the buffer has been modified by * the currently running transaction * [b_state_lock] */ unsigned b_modified;
/* * Copy of the buffer data frozen for writing to the log. * [b_state_lock] */ 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. [b_state_lock] */ 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] [b_state_lock] * Either of these locks is enough for reading, both are needed for * changes. */ 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] [b_state_lock] */ transaction_t *b_next_transaction;
/* * Doubly-linked list of buffers on a transaction's data, metadata or * forget queue. [t_list_lock] [b_state_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. * [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;
/* Trigger type */ struct jbd2_buffer_trigger_type *b_triggers;
/* Trigger type for the committing transaction's frozen data */ struct jbd2_buffer_trigger_type *b_frozen_triggers;};
#endif /* JOURNAL_HEAD_H_INCLUDED */