jbd2: fix checkpoint list cleanup

Unlike comments and expectation of callers journal_clean_one_cp_list()
returned 1 not only if it freed the transaction but also if it freed
some buffers in the transaction. That could make
__jbd2_journal_clean_checkpoint_list() skip processing
t_checkpoint_io_list and continue with processing the next transaction.
This is mostly a cosmetic issue since the only result is we can
sometimes free less memory than we could. But it's still worth fixing.
Fix journal_clean_one_cp_list() to return 1 only if the transaction was
really freed.

Fixes: 50849db32a9f529235a84bcc84a6b8e631b1d0ec
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

1 files changed, 3 insertions, 5 deletions

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 8c44654ce274..684996c8a3a4 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -427,7 +427,6 @@ static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
         struct journal_head *last_jh;
         struct journal_head *next_jh = jh;
         int ret;
-        int freed = 0;
 
         if (!jh)
                 return 0;
@@ -441,10 +440,9 @@ static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
                 else
                         ret = __jbd2_journal_remove_checkpoint(jh) + 1;
                 if (!ret)
-                        return freed;
+                        return 0;
                 if (ret == 2)
                         return 1;
-                freed = 1;
                 /*
                  * This function only frees up some memory
                  * if possible so we dont have an obligation
@@ -452,10 +450,10 @@ static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
                  * requested:
                  */
                 if (need_resched())
-                        return freed;
+                        return 0;
         } while (jh != last_jh);
 
-        return freed;
+        return 0;
 }
 
 /*