1b2441318SGreg Kroah-Hartman /* SPDX-License-Identifier: GPL-2.0 */ 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * include/linux/journal-head.h 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * buffer_head fields for JBD 61da177e4SLinus Torvalds * 7e1f8e874SFrancois Cami * 27 May 2001 Andrew Morton 81da177e4SLinus Torvalds * Created - pulled out of fs.h 91da177e4SLinus Torvalds */ 101da177e4SLinus Torvalds 111da177e4SLinus Torvalds #ifndef JOURNAL_HEAD_H_INCLUDED 121da177e4SLinus Torvalds #define JOURNAL_HEAD_H_INCLUDED 131da177e4SLinus Torvalds 14*46417064SThomas Gleixner #include <linux/spinlock.h> 15*46417064SThomas Gleixner 161da177e4SLinus Torvalds typedef unsigned int tid_t; /* Unique transaction ID */ 171da177e4SLinus Torvalds typedef struct transaction_s transaction_t; /* Compound transaction type */ 18e06c8227SJoel Becker 19e06c8227SJoel Becker 201da177e4SLinus Torvalds struct buffer_head; 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds struct journal_head { 231da177e4SLinus Torvalds /* 241da177e4SLinus Torvalds * Points back to our buffer_head. [jbd_lock_bh_journal_head()] 251da177e4SLinus Torvalds */ 261da177e4SLinus Torvalds struct buffer_head *b_bh; 271da177e4SLinus Torvalds 281da177e4SLinus Torvalds /* 29*46417064SThomas Gleixner * Protect the buffer head state 30*46417064SThomas Gleixner */ 31*46417064SThomas Gleixner spinlock_t b_state_lock; 32*46417064SThomas Gleixner 33*46417064SThomas Gleixner /* 341da177e4SLinus Torvalds * Reference count - see description in journal.c 351da177e4SLinus Torvalds * [jbd_lock_bh_journal_head()] 361da177e4SLinus Torvalds */ 371da177e4SLinus Torvalds int b_jcount; 381da177e4SLinus Torvalds 391da177e4SLinus Torvalds /* 40*46417064SThomas Gleixner * Journalling list for this buffer [b_state_lock] 41e2555fdeSJan Kara * NOTE: We *cannot* combine this with b_modified into a bitfield 42e2555fdeSJan Kara * as gcc would then (which the C standard allows but which is 43e2555fdeSJan Kara * very unuseful) make 64-bit accesses to the bitfield and clobber 44e2555fdeSJan Kara * b_jcount if its update races with bitfield modification. 451da177e4SLinus Torvalds */ 46e2555fdeSJan Kara unsigned b_jlist; 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds /* 491da177e4SLinus Torvalds * This flag signals the buffer has been modified by 501da177e4SLinus Torvalds * the currently running transaction 51*46417064SThomas Gleixner * [b_state_lock] 521da177e4SLinus Torvalds */ 53e2555fdeSJan Kara unsigned b_modified; 54c2cc7028SAmir Goldstein 55c2cc7028SAmir Goldstein /* 561da177e4SLinus Torvalds * Copy of the buffer data frozen for writing to the log. 57*46417064SThomas Gleixner * [b_state_lock] 581da177e4SLinus Torvalds */ 591da177e4SLinus Torvalds char *b_frozen_data; 601da177e4SLinus Torvalds 611da177e4SLinus Torvalds /* 621da177e4SLinus Torvalds * Pointer to a saved copy of the buffer containing no uncommitted 631da177e4SLinus Torvalds * deallocation references, so that allocations can avoid overwriting 64*46417064SThomas Gleixner * uncommitted deletes. [b_state_lock] 651da177e4SLinus Torvalds */ 661da177e4SLinus Torvalds char *b_committed_data; 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds /* 691da177e4SLinus Torvalds * Pointer to the compound transaction which owns this buffer's 701da177e4SLinus Torvalds * metadata: either the running transaction or the committing 711da177e4SLinus Torvalds * transaction (if there is one). Only applies to buffers on a 721da177e4SLinus Torvalds * transaction's data or metadata journaling list. 73*46417064SThomas Gleixner * [j_list_lock] [b_state_lock] 74932bb305SJan Kara * Either of these locks is enough for reading, both are needed for 75932bb305SJan Kara * changes. 761da177e4SLinus Torvalds */ 771da177e4SLinus Torvalds transaction_t *b_transaction; 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds /* 801da177e4SLinus Torvalds * Pointer to the running compound transaction which is currently 811da177e4SLinus Torvalds * modifying the buffer's metadata, if there was already a transaction 821da177e4SLinus Torvalds * committing it when the new transaction touched it. 83*46417064SThomas Gleixner * [t_list_lock] [b_state_lock] 841da177e4SLinus Torvalds */ 851da177e4SLinus Torvalds transaction_t *b_next_transaction; 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds /* 881da177e4SLinus Torvalds * Doubly-linked list of buffers on a transaction's data, metadata or 89*46417064SThomas Gleixner * forget queue. [t_list_lock] [b_state_lock] 901da177e4SLinus Torvalds */ 911da177e4SLinus Torvalds struct journal_head *b_tnext, *b_tprev; 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds /* 941da177e4SLinus Torvalds * Pointer to the compound transaction against which this buffer 951da177e4SLinus Torvalds * is checkpointed. Only dirty buffers can be checkpointed. 961da177e4SLinus Torvalds * [j_list_lock] 971da177e4SLinus Torvalds */ 981da177e4SLinus Torvalds transaction_t *b_cp_transaction; 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds /* 1011da177e4SLinus Torvalds * Doubly-linked list of buffers still remaining to be flushed 1021da177e4SLinus Torvalds * before an old transaction can be checkpointed. 1031da177e4SLinus Torvalds * [j_list_lock] 1041da177e4SLinus Torvalds */ 1051da177e4SLinus Torvalds struct journal_head *b_cpnext, *b_cpprev; 106e06c8227SJoel Becker 107e06c8227SJoel Becker /* Trigger type */ 108e06c8227SJoel Becker struct jbd2_buffer_trigger_type *b_triggers; 109e06c8227SJoel Becker 110e06c8227SJoel Becker /* Trigger type for the committing transaction's frozen data */ 111e06c8227SJoel Becker struct jbd2_buffer_trigger_type *b_frozen_triggers; 1121da177e4SLinus Torvalds }; 1131da177e4SLinus Torvalds 1141da177e4SLinus Torvalds #endif /* JOURNAL_HEAD_H_INCLUDED */ 115