jbd2: minimize region locked by j_list_lock in jbd2_journal_forget()

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>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 357f3dc5201f..d999b1f6847c 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1416,7 +1416,6 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
         BUFFER_TRACE(bh, "entry");
 
         jbd_lock_bh_state(bh);
-        spin_lock(&journal->j_list_lock);
 
         if (!buffer_jbd(bh))
                 goto not_jbd;
@@ -1469,6 +1468,7 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
                  * we know to remove the checkpoint after we commit.
                  */
 
+                spin_lock(&journal->j_list_lock);
                 if (jh->b_cp_transaction) {
                         __jbd2_journal_temp_unlink_buffer(jh);
                         __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
@@ -1481,6 +1481,7 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
                                 goto drop;
                         }
                 }
+                spin_unlock(&journal->j_list_lock);
         } else if (jh->b_transaction) {
                 J_ASSERT_JH(jh, (jh->b_transaction ==
                                  journal->j_committing_transaction));
@@ -1492,7 +1493,9 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
 
                 if (jh->b_next_transaction) {
                         J_ASSERT(jh->b_next_transaction == transaction);
+                        spin_lock(&journal->j_list_lock);
                         jh->b_next_transaction = NULL;
+                        spin_unlock(&journal->j_list_lock);
 
                         /*
                          * only drop a reference if this transaction modified
@@ -1504,7 +1507,6 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
         }
 
 not_jbd:
-        spin_unlock(&journal->j_list_lock);
         jbd_unlock_bh_state(bh);
         __brelse(bh);
 drop: