3 files changed, 12 insertions, 10 deletions

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 3fccde7ba008..7e958c86242f 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -602,15 +602,15 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 
         /*
          * There is one special case to worry about: if we have just pulled the
-         * buffer off a committing transaction's forget list, then even if the
-         * checkpoint list is empty, the transaction obviously cannot be
-         * dropped!
+         * buffer off a running or committing transaction's checkpoing list,
+         * then even if the checkpoint list is empty, the transaction obviously
+         * cannot be dropped!
          *
-         * The locking here around j_committing_transaction is a bit sleazy.
+         * The locking here around t_state is a bit sleazy.
          * See the comment at the end of jbd2_journal_commit_transaction().
          */
-        if (transaction == journal->j_committing_transaction) {
-                JBUFFER_TRACE(jh, "belongs to committing transaction");
+        if (transaction->t_state != T_FINISHED) {
+                JBUFFER_TRACE(jh, "belongs to running/committing transaction");
                 goto out;
         }
 
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 6986f334c643..39b5cee3dd8a 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -867,10 +867,10 @@ restart_loop:
         }
         spin_unlock(&journal->j_list_lock);
         /*
-         * This is a bit sleazy.  We borrow j_list_lock to protect
-         * journal->j_committing_transaction in __jbd2_journal_remove_checkpoint.
-         * Really, __jbd2_journal_remove_checkpoint should be using j_state_lock but
-         * it's a bit hassle to hold that across __jbd2_journal_remove_checkpoint
+         * This is a bit sleazy.  We use j_list_lock to protect transition
+         * of a transaction into T_FINISHED state and calling
+         * __jbd2_journal_drop_transaction(). Otherwise we could race with
+         * other checkpointing code processing the transaction...
          */
         spin_lock(&journal->j_state_lock);
         spin_lock(&journal->j_list_lock);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index d5f7cff4cb28..d861ffd49821 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -442,6 +442,8 @@ struct transaction_s
         /*
          * Transaction's current state
          * [no locking - only kjournald2 alters this]
+         * [j_list_lock] guards transition of a transaction into T_FINISHED
+         * state and subsequent call of __jbd2_journal_drop_transaction()
          * FIXME: needs barriers
          * KLUDGE: [use j_state_lock]
          */