jbd2: minimize region locked by j_list_lock in journal_get_create_access()

It's not needed until we start trying to modifying fields in the
journal_head which are protected by j_list_lock.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 78900a1..357f3dc 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1073,7 +1073,6 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
         * reused here.
         */
        jbd_lock_bh_state(bh);
-       spin_lock(&journal->j_list_lock);
        J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
                jh->b_transaction == NULL ||
                (jh->b_transaction == journal->j_committing_transaction &&
@@ -1096,12 +1095,14 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
                jh->b_modified = 0;
 
                JBUFFER_TRACE(jh, "file as BJ_Reserved");
+               spin_lock(&journal->j_list_lock);
                __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
        } else if (jh->b_transaction == journal->j_committing_transaction) {
                /* first access by this transaction */
                jh->b_modified = 0;
 
                JBUFFER_TRACE(jh, "set next transaction");
+               spin_lock(&journal->j_list_lock);
                jh->b_next_transaction = transaction;
        }
        spin_unlock(&journal->j_list_lock);