'\" t .\" Title: struct journal_s .\" Author: .\" Generator: DocBook XSL Stylesheets v1.79.1 .\" Date: June 2017 .\" Manual: The Linux Journalling API .\" Source: Kernel Hackers Manual 4.9.30 .\" Language: English .\" .TH "STRUCT JOURNAL_S" "9" "June 2017" "Kernel Hackers Manual 4\&.9\&." "The Linux Journalling API" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" struct_journal_s \- The journal_s type is the concrete type associated with journal_t\&. .SH "SYNOPSIS" .sp .nf struct journal_s { unsigned long j_flags; int j_errno; struct buffer_head * j_sb_buffer; journal_superblock_t * j_superblock; int j_format_version; rwlock_t j_state_lock; int j_barrier_count; struct mutex j_barrier; transaction_t * j_running_transaction; transaction_t * j_committing_transaction; transaction_t * j_checkpoint_transactions; wait_queue_head_t j_wait_transaction_locked; wait_queue_head_t j_wait_done_commit; wait_queue_head_t j_wait_commit; wait_queue_head_t j_wait_updates; wait_queue_head_t j_wait_reserved; struct mutex j_checkpoint_mutex; unsigned long j_head; unsigned long j_tail; unsigned long j_free; unsigned long j_first; unsigned long j_last; struct block_device * j_dev; int j_blocksize; unsigned long long j_blk_offset; struct block_device * j_fs_dev; unsigned int j_maxlen; atomic_t j_reserved_credits; spinlock_t j_list_lock; struct inode * j_inode; tid_t j_tail_sequence; tid_t j_transaction_sequence; tid_t j_commit_sequence; tid_t j_commit_request; __u8 j_uuid[16]; struct task_struct * j_task; int j_max_transaction_buffers; unsigned long j_commit_interval; struct timer_list j_commit_timer; spinlock_t j_revoke_lock; struct jbd2_revoke_table_s * j_revoke; struct jbd2_revoke_table_s * j_revoke_table[2]; struct buffer_head ** j_wbuf; int j_wbufsize; pid_t j_last_sync_writer; spinlock_t j_history_lock; struct proc_dir_entry * j_proc_entry; struct transaction_stats_s j_stats; void * j_private; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map j_trans_commit_map; #endif }; .fi .SH "MEMBERS" .PP j_flags .RS 4 General journaling state flags .RE .PP j_errno .RS 4 Is there an outstanding uncleared error on the journal (from a prior abort)? .RE .PP j_sb_buffer .RS 4 First part of superblock buffer .RE .PP j_superblock .RS 4 Second part of superblock buffer .RE .PP j_format_version .RS 4 Version of the superblock format .RE .PP j_state_lock .RS 4 Protect the various scalars in the journal .RE .PP j_barrier_count .RS 4 Number of processes waiting to create a barrier lock .RE .PP j_barrier .RS 4 The barrier lock itself .RE .PP j_running_transaction .RS 4 The current running transaction\&.\&. .RE .PP j_committing_transaction .RS 4 the transaction we are pushing to disk .RE .PP j_checkpoint_transactions .RS 4 a linked circular list of all transactions waiting for checkpointing .RE .PP j_wait_transaction_locked .RS 4 Wait queue for waiting for a locked transaction to start committing, or for a barrier lock to be released .RE .PP j_wait_done_commit .RS 4 Wait queue for waiting for commit to complete .RE .PP j_wait_commit .RS 4 Wait queue to trigger commit .RE .PP j_wait_updates .RS 4 Wait queue to wait for updates to complete .RE .PP j_wait_reserved .RS 4 Wait queue to wait for reserved buffer credits to drop .RE .PP j_checkpoint_mutex .RS 4 Mutex for locking against concurrent checkpoints .RE .PP j_head .RS 4 Journal head \- identifies the first unused block in the journal .RE .PP j_tail .RS 4 Journal tail \- identifies the oldest still\-used block in the journal\&. .RE .PP j_free .RS 4 Journal free \- how many free blocks are there in the journal? .RE .PP j_first .RS 4 The block number of the first usable block .RE .PP j_last .RS 4 The block number one beyond the last usable block .RE .PP j_dev .RS 4 Device where we store the journal .RE .PP j_blocksize .RS 4 blocksize for the location where we store the journal\&. .RE .PP j_blk_offset .RS 4 starting block offset for into the device where we store the journal .RE .PP j_fs_dev .RS 4 Device which holds the client fs\&. For internal journal this will be equal to j_dev .RE .PP j_maxlen .RS 4 Total maximum capacity of the journal region on disk\&. .RE .PP j_reserved_credits .RS 4 Number of buffers reserved from the running transaction .RE .PP j_list_lock .RS 4 Protects the buffer lists and internal buffer state\&. .RE .PP j_inode .RS 4 Optional inode where we store the journal\&. If present, all journal block numbers are mapped into this inode via \fBbmap\fR\&. .RE .PP j_tail_sequence .RS 4 Sequence number of the oldest transaction in the log .RE .PP j_transaction_sequence .RS 4 Sequence number of the next transaction to grant .RE .PP j_commit_sequence .RS 4 Sequence number of the most recently committed transaction .RE .PP j_commit_request .RS 4 Sequence number of the most recent transaction wanting commit .RE .PP j_uuid[16] .RS 4 Uuid of client object\&. .RE .PP j_task .RS 4 Pointer to the current commit thread for this journal .RE .PP j_max_transaction_buffers .RS 4 Maximum number of metadata buffers to allow in a single compound commit transaction .RE .PP j_commit_interval .RS 4 What is the maximum transaction lifetime before we begin a commit? .RE .PP j_commit_timer .RS 4 The timer used to wakeup the commit thread .RE .PP j_revoke_lock .RS 4 Protect the revoke table .RE .PP j_revoke .RS 4 The revoke table \- maintains the list of revoked blocks in the current transaction\&. .RE .PP j_revoke_table[2] .RS 4 alternate revoke tables for j_revoke .RE .PP j_wbuf .RS 4 array of buffer_heads for jbd2_journal_commit_transaction .RE .PP j_wbufsize .RS 4 maximum number of buffer_heads allowed in j_wbuf, the number that will fit in j_blocksize .RE .PP j_last_sync_writer .RS 4 most recent pid which did a synchronous write .RE .PP j_history_lock .RS 4 Protect the transactions statistics history .RE .PP j_proc_entry .RS 4 procfs entry for the jbd statistics directory .RE .PP j_stats .RS 4 Overall statistics .RE .PP j_private .RS 4 An opaque pointer to fs\-private information\&. .RE .PP j_trans_commit_map .RS 4 Lockdep entity to track transaction commit dependencies .RE .SH "AUTHORS" .PP \fBRoger Gammans\fR <\&rgammans@computer-surgery.co.uk\&> .RS 4 Author. .RE .PP \fBStephen Tweedie\fR <\&sct@redhat.com\&> .RS 4 Author. .RE .SH "COPYRIGHT" .br