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Commit 9ff86446 authored by Dmitry Monakhov's avatar Dmitry Monakhov Committed by Theodore Ts'o
Browse files

jbd2: optimize jbd2_journal_force_commit 



Current implementation of jbd2_journal_force_commit() is suboptimal because
result in empty and useless commits. But callers just want to force and wait
any unfinished commits. We already have jbd2_journal_force_commit_nested()
which does exactly what we want, except we are guaranteed that we do not hold
journal transaction open.

Signed-off-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 981250ca

fs/jbd2/journal.c

+48 −14
Original line number Diff line number Diff line
@@ -529,20 +529,17 @@ int jbd2_log_start_commit(journal_t *journal, tid_t tid) 
}



/*

 * Force and wait upon a commit if the calling process is not within

 * transaction.  This is used for forcing out undo-protected data which contains

 * bitmaps, when the fs is running out of space.

 *

 * We can only force the running transaction if we don't have an active handle;

 * otherwise, we will deadlock.

 *

 * Returns true if a transaction was started.

 * Force and wait any uncommitted transactions.  We can only force the running

 * transaction if we don't have an active handle, otherwise, we will deadlock.

 * Returns: <0 in case of error,

 *           0 if nothing to commit,

 *           1 if transaction was successfully committed.

 */

int jbd2_journal_force_commit_nested(journal_t *journal)

static int __jbd2_journal_force_commit(journal_t *journal)

{

	transaction_t *transaction = NULL;

	tid_t tid;

	int need_to_start = 0;

	int need_to_start = 0, ret = 0;



	read_lock(&journal->j_state_lock);

	if (journal->j_running_transaction && !current->journal_info) {
@@ -553,16 +550,53 @@ int jbd2_journal_force_commit_nested(journal_t *journal) 
		transaction = journal->j_committing_transaction;



	if (!transaction) {

		/* Nothing to commit */

		read_unlock(&journal->j_state_lock);

		return 0;	/* Nothing to retry */

		return 0;

	}



	tid = transaction->t_tid;

	read_unlock(&journal->j_state_lock);

	if (need_to_start)

		jbd2_log_start_commit(journal, tid);

	jbd2_log_wait_commit(journal, tid);

	return 1;

	ret = jbd2_log_wait_commit(journal, tid);

	if (!ret)

		ret = 1;



	return ret;

}



/**

 * Force and wait upon a commit if the calling process is not within

 * transaction.  This is used for forcing out undo-protected data which contains

 * bitmaps, when the fs is running out of space.

 *

 * @journal: journal to force

 * Returns true if progress was made.

 */

int jbd2_journal_force_commit_nested(journal_t *journal)

{

	int ret;



	ret = __jbd2_journal_force_commit(journal);

	return ret > 0;

}



/**

 * int journal_force_commit() - force any uncommitted transactions

 * @journal: journal to force

 *

 * Caller want unconditional commit. We can only force the running transaction

 * if we don't have an active handle, otherwise, we will deadlock.

 */

int jbd2_journal_force_commit(journal_t *journal)

{

	int ret;



	J_ASSERT(!current->journal_info);

	ret = __jbd2_journal_force_commit(journal);

	if (ret > 0)

		ret = 0;

	return ret;

}



/*

fs/jbd2/transaction.c

+0 −23
Original line number Diff line number Diff line
@@ -1661,29 +1661,6 @@ int jbd2_journal_stop(handle_t *handle) 
	return err;

}



/**

 * int jbd2_journal_force_commit() - force any uncommitted transactions

 * @journal: journal to force

 *

 * For synchronous operations: force any uncommitted transactions

 * to disk.  May seem kludgy, but it reuses all the handle batching

 * code in a very simple manner.

 */

int jbd2_journal_force_commit(journal_t *journal)

{

	handle_t *handle;

	int ret;



	handle = jbd2_journal_start(journal, 1);

	if (IS_ERR(handle)) {

		ret = PTR_ERR(handle);

	} else {

		handle->h_sync = 1;

		ret = jbd2_journal_stop(handle);

	}

	return ret;

}



/*

 *

 * List management code snippets: various functions for manipulating the

include/linux/jbd2.h

+1 −1
Original line number Diff line number Diff line
@@ -1160,6 +1160,7 @@ extern void jbd2_journal_ack_err (journal_t *); 
extern int	   jbd2_journal_clear_err  (journal_t *);

extern int	   jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);

extern int	   jbd2_journal_force_commit(journal_t *);

extern int	   jbd2_journal_force_commit_nested(journal_t *);

extern int	   jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *inode);

extern int	   jbd2_journal_begin_ordered_truncate(journal_t *journal,

				struct jbd2_inode *inode, loff_t new_size);
@@ -1235,7 +1236,6 @@ extern void jbd2_clear_buffer_revoked_flags(journal_t *journal); 
int jbd2_log_start_commit(journal_t *journal, tid_t tid);

int __jbd2_log_start_commit(journal_t *journal, tid_t tid);

int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);

int jbd2_journal_force_commit_nested(journal_t *journal);

int jbd2_log_wait_commit(journal_t *journal, tid_t tid);

int jbd2_complete_transaction(journal_t *journal, tid_t tid);

int jbd2_log_do_checkpoint(journal_t *journal);