jbd2: clean up jbd2_journal_try_to_free_buffers()

This patch reverts 3f31fddf, which is no longer needed because if a
race between freeing buffer and committing transaction functionality
occurs and dio gets error, currently dio falls back to buffered IO due
to the commit 6ccfa806.

Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Cc: Mingming Cao <cmm@us.ibm.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 996ffda..494501e 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1547,36 +1547,6 @@ out:
        return;
 }
 
-/*
- * jbd2_journal_try_to_free_buffers() could race with
- * jbd2_journal_commit_transaction(). The later might still hold the
- * reference count to the buffers when inspecting them on
- * t_syncdata_list or t_locked_list.
- *
- * jbd2_journal_try_to_free_buffers() will call this function to
- * wait for the current transaction to finish syncing data buffers, before
- * try to free that buffer.
- *
- * Called with journal->j_state_lock hold.
- */
-static void jbd2_journal_wait_for_transaction_sync_data(journal_t *journal)
-{
-       transaction_t *transaction;
-       tid_t tid;
-
-       spin_lock(&journal->j_state_lock);
-       transaction = journal->j_committing_transaction;
-
-       if (!transaction) {
-               spin_unlock(&journal->j_state_lock);
-               return;
-       }
-
-       tid = transaction->t_tid;
-       spin_unlock(&journal->j_state_lock);
-       jbd2_log_wait_commit(journal, tid);
-}
-
 /**
  * int jbd2_journal_try_to_free_buffers() - try to free page buffers.
  * @journal: journal for operation
@@ -1649,25 +1619,6 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
 
        ret = try_to_free_buffers(page);
 
-       /*
-        * There are a number of places where jbd2_journal_try_to_free_buffers()
-        * could race with jbd2_journal_commit_transaction(), the later still
-        * holds the reference to the buffers to free while processing them.
-        * try_to_free_buffers() failed to free those buffers. Some of the
-        * caller of releasepage() request page buffers to be dropped, otherwise
-        * treat the fail-to-free as errors (such as generic_file_direct_IO())
-        *
-        * So, if the caller of try_to_release_page() wants the synchronous
-        * behaviour(i.e make sure buffers are dropped upon return),
-        * let's wait for the current transaction to finish flush of
-        * dirty data buffers, then try to free those buffers again,
-        * with the journal locked.
-        */
-       if (ret == 0 && (gfp_mask & __GFP_WAIT) && (gfp_mask & __GFP_FS)) {
-               jbd2_journal_wait_for_transaction_sync_data(journal);
-               ret = try_to_free_buffers(page);
-       }
-
 busy:
        return ret;
 }