Commit 34fc8768 authored by Andrew Perepechko's avatar Andrew Perepechko Committed by Theodore Ts'o
Browse files

jbd2: wake up journal waiters in FIFO order, not LIFO 



LIFO wakeup order is unfair and sometimes leads to a journal
user not being able to get a journal handle for hundreds of
transactions in a row.

FIFO wakeup can make things more fair.

Cc: stable@kernel.org
Signed-off-by: default avatarAlexey Lyashkov <alexey.lyashkov@gmail.com>
Reviewed-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20220907165959.1137482-1-alexey.lyashkov@gmail.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent d1052d23

fs/jbd2/commit.c

+1 −1
Original line number Diff line number Diff line
@@ -568,7 +568,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) 
	journal->j_running_transaction = NULL;

	start_time = ktime_get();

	commit_transaction->t_log_start = journal->j_head;

	wake_up(&journal->j_wait_transaction_locked);

	wake_up_all(&journal->j_wait_transaction_locked);

	write_unlock(&journal->j_state_lock);



	jbd2_debug(3, "JBD2: commit phase 2a\n");

fs/jbd2/transaction.c

+3 −3
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ static void wait_transaction_locked(journal_t *journal) 
	int need_to_start;

	tid_t tid = journal->j_running_transaction->t_tid;



	prepare_to_wait(&journal->j_wait_transaction_locked, &wait,

	prepare_to_wait_exclusive(&journal->j_wait_transaction_locked, &wait,

			TASK_UNINTERRUPTIBLE);

	need_to_start = !tid_geq(journal->j_commit_request, tid);

	read_unlock(&journal->j_state_lock);
@@ -194,7 +194,7 @@ static void wait_transaction_switching(journal_t *journal) 
		read_unlock(&journal->j_state_lock);

		return;

	}

	prepare_to_wait(&journal->j_wait_transaction_locked, &wait,

	prepare_to_wait_exclusive(&journal->j_wait_transaction_locked, &wait,

			TASK_UNINTERRUPTIBLE);

	read_unlock(&journal->j_state_lock);

	/*
@@ -920,7 +920,7 @@ void jbd2_journal_unlock_updates (journal_t *journal) 
	write_lock(&journal->j_state_lock);

	--journal->j_barrier_count;

	write_unlock(&journal->j_state_lock);

	wake_up(&journal->j_wait_transaction_locked);

	wake_up_all(&journal->j_wait_transaction_locked);

}



static void warn_dirty_buffer(struct buffer_head *bh)