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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>struct journal_s</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Linux Filesystems API" /><link rel="up" href="ch05s02.html#structures" title="Structures" /><link rel="prev" href="re177.html" title="struct handle_s" /><link rel="next" href="ch05s03.html" title="Functions" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>struct journal_s</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re177.html">Prev</a> </td><th width="60%" align="center">Structures</th><td width="20%" align="right"> <a accesskey="n" href="ch05s03.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="struct journal_s"><a id="API-struct-journal-s"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>struct journal_s —
this is the concrete type associated with journal_t.
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><pre class="programlisting">
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;
spinlock_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_logspace;
wait_queue_head_t j_wait_done_commit;
wait_queue_head_t j_wait_checkpoint;
wait_queue_head_t j_wait_commit;
wait_queue_head_t j_wait_updates;
struct mutex j_checkpoint_mutex;
unsigned int j_head;
unsigned int j_tail;
unsigned int j_free;
unsigned int j_first;
unsigned int j_last;
struct block_device * j_dev;
int j_blocksize;
unsigned int j_blk_offset;
struct block_device * j_fs_dev;
unsigned int j_maxlen;
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 jbd_revoke_table_s * j_revoke;
struct jbd_revoke_table_s * j_revoke_table[2];
struct buffer_head ** j_wbuf;
int j_wbufsize;
pid_t j_last_sync_writer;
u64 j_average_commit_time;
void * j_private;
}; </pre></div><div class="refsect1" title="Members"><a id="id3031133"></a><h2>Members</h2><div class="variablelist"><dl><dt><span class="term">j_flags</span></dt><dd><p>
General journaling state flags
</p></dd><dt><span class="term">j_errno</span></dt><dd><p>
Is there an outstanding uncleared error on the journal (from a
prior abort)?
</p></dd><dt><span class="term">j_sb_buffer</span></dt><dd><p>
First part of superblock buffer
</p></dd><dt><span class="term">j_superblock</span></dt><dd><p>
Second part of superblock buffer
</p></dd><dt><span class="term">j_format_version</span></dt><dd><p>
Version of the superblock format
</p></dd><dt><span class="term">j_state_lock</span></dt><dd><p>
Protect the various scalars in the journal
</p></dd><dt><span class="term">j_barrier_count</span></dt><dd><p>
Number of processes waiting to create a barrier lock
</p></dd><dt><span class="term">j_barrier</span></dt><dd><p>
The barrier lock itself
</p></dd><dt><span class="term">j_running_transaction</span></dt><dd><p>
The current running transaction..
</p></dd><dt><span class="term">j_committing_transaction</span></dt><dd><p>
the transaction we are pushing to disk
</p></dd><dt><span class="term">j_checkpoint_transactions</span></dt><dd><p>
a linked circular list of all transactions
waiting for checkpointing
</p></dd><dt><span class="term">j_wait_transaction_locked</span></dt><dd><p>
Wait queue for waiting for a locked transaction
to start committing, or for a barrier lock to be released
</p></dd><dt><span class="term">j_wait_logspace</span></dt><dd><p>
Wait queue for waiting for checkpointing to complete
</p></dd><dt><span class="term">j_wait_done_commit</span></dt><dd><p>
Wait queue for waiting for commit to complete
</p></dd><dt><span class="term">j_wait_checkpoint</span></dt><dd><p>
Wait queue to trigger checkpointing
</p></dd><dt><span class="term">j_wait_commit</span></dt><dd><p>
Wait queue to trigger commit
</p></dd><dt><span class="term">j_wait_updates</span></dt><dd><p>
Wait queue to wait for updates to complete
</p></dd><dt><span class="term">j_checkpoint_mutex</span></dt><dd><p>
Mutex for locking against concurrent checkpoints
</p></dd><dt><span class="term">j_head</span></dt><dd><p>
Journal head - identifies the first unused block in the journal
</p></dd><dt><span class="term">j_tail</span></dt><dd><p>
Journal tail - identifies the oldest still-used block in the
journal.
</p></dd><dt><span class="term">j_free</span></dt><dd><p>
Journal free - how many free blocks are there in the journal?
</p></dd><dt><span class="term">j_first</span></dt><dd><p>
The block number of the first usable block
</p></dd><dt><span class="term">j_last</span></dt><dd><p>
The block number one beyond the last usable block
</p></dd><dt><span class="term">j_dev</span></dt><dd><p>
Device where we store the journal
</p></dd><dt><span class="term">j_blocksize</span></dt><dd><p>
blocksize for the location where we store the journal.
</p></dd><dt><span class="term">j_blk_offset</span></dt><dd><p>
starting block offset for into the device where we store the
journal
</p></dd><dt><span class="term">j_fs_dev</span></dt><dd><p>
Device which holds the client fs. For internal journal this will
be equal to j_dev
</p></dd><dt><span class="term">j_maxlen</span></dt><dd><p>
Total maximum capacity of the journal region on disk.
</p></dd><dt><span class="term">j_list_lock</span></dt><dd><p>
Protects the buffer lists and internal buffer state.
</p></dd><dt><span class="term">j_inode</span></dt><dd><p>
Optional inode where we store the journal. If present, all journal
block numbers are mapped into this inode via <code class="function">bmap</code>.
</p></dd><dt><span class="term">j_tail_sequence</span></dt><dd><p>
Sequence number of the oldest transaction in the log
</p></dd><dt><span class="term">j_transaction_sequence</span></dt><dd><p>
Sequence number of the next transaction to grant
</p></dd><dt><span class="term">j_commit_sequence</span></dt><dd><p>
Sequence number of the most recently committed
transaction
</p></dd><dt><span class="term">j_commit_request</span></dt><dd><p>
Sequence number of the most recent transaction wanting
commit
</p></dd><dt><span class="term">j_uuid[16]</span></dt><dd><p>
Uuid of client object.
</p></dd><dt><span class="term">j_task</span></dt><dd><p>
Pointer to the current commit thread for this journal
</p></dd><dt><span class="term">j_max_transaction_buffers</span></dt><dd><p>
Maximum number of metadata buffers to allow in a
single compound commit transaction
</p></dd><dt><span class="term">j_commit_interval</span></dt><dd><p>
What is the maximum transaction lifetime before we begin
a commit?
</p></dd><dt><span class="term">j_commit_timer</span></dt><dd><p>
The timer used to wakeup the commit thread
</p></dd><dt><span class="term">j_revoke_lock</span></dt><dd><p>
Protect the revoke table
</p></dd><dt><span class="term">j_revoke</span></dt><dd><p>
The revoke table - maintains the list of revoked blocks in the
current transaction.
</p></dd><dt><span class="term">j_revoke_table[2]</span></dt><dd><p>
alternate revoke tables for j_revoke
</p></dd><dt><span class="term">j_wbuf</span></dt><dd><p>
array of buffer_heads for journal_commit_transaction
</p></dd><dt><span class="term">j_wbufsize</span></dt><dd><p>
maximum number of buffer_heads allowed in j_wbuf, the
number that will fit in j_blocksize
</p></dd><dt><span class="term">j_last_sync_writer</span></dt><dd><p>
most recent pid which did a synchronous write
</p></dd><dt><span class="term">j_average_commit_time</span></dt><dd><p>
the average amount of time in nanoseconds it
takes to commit a transaction to the disk.
</p></dd><dt><span class="term">j_private</span></dt><dd><p>
An opaque pointer to fs-private information.
</p></dd></dl></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re177.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch05s02.html#structures">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch05s03.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>struct handle_s</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Functions</td></tr></table></div></body></html>
