save-some-atomic-ops-in-JI_COMMIT_RUNNING-handling

   1 jbd2: save some atomic ops in __JI_COMMIT_RUNNING handling
   2
   3 From: Jan Kara <jack@suse.cz>
   4
   5 Currently we used atomic bit operations to manipulate
   6 __JI_COMMIT_RUNNING bit. However this is unnecessary as i_flags are
   7 always written and read under j_list_lock. So just change the operations
   8 to standard bit operations.
   9
  10 Signed-off-by: Jan Kara <jack@suse.cz>
  11 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  12 ---
  13  fs/jbd2/commit.c  | 12 ++++++------
  14  fs/jbd2/journal.c |  2 +-
  15  2 files changed, 7 insertions(+), 7 deletions(-)
  16
  17 diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
  18 index ae832cd44dd8..517f2de784cf 100644
  19 --- a/fs/jbd2/commit.c
  20 +++ b/fs/jbd2/commit.c
  21 @@ -220,7 +220,7 @@ static int journal_submit_data_buffers(journal_t *journal,
  22         spin_lock(&journal->j_list_lock);
  23         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
  24                 mapping = jinode->i_vfs_inode->i_mapping;
  25 -               set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
  26 +               jinode->i_flags |= JI_COMMIT_RUNNING;
  27                 spin_unlock(&journal->j_list_lock);
  28                 /*
  29                  * submit the inode data buffers. We use writepage
  30 @@ -234,8 +234,8 @@ static int journal_submit_data_buffers(journal_t *journal,
  31                         ret = err;
  32                 spin_lock(&journal->j_list_lock);
  33                 J_ASSERT(jinode->i_transaction == commit_transaction);
  34 -               clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
  35 -               smp_mb__after_atomic();
  36 +               jinode->i_flags &= ~JI_COMMIT_RUNNING;
  37 +               smp_mb();
  38                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
  39         }
  40         spin_unlock(&journal->j_list_lock);
  41 @@ -256,7 +256,7 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
  42         /* For locking, see the comment in journal_submit_data_buffers() */
  43         spin_lock(&journal->j_list_lock);
  44         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
  45 -               set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
  46 +               jinode->i_flags |= JI_COMMIT_RUNNING;
  47                 spin_unlock(&journal->j_list_lock);
  48                 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
  49                 if (err) {
  50 @@ -272,8 +272,8 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
  51                                 ret = err;
  52                 }
  53                 spin_lock(&journal->j_list_lock);
  54 -               clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
  55 -               smp_mb__after_atomic();
  56 +               jinode->i_flags &= ~JI_COMMIT_RUNNING;
  57 +               smp_mb();
  58                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
  59         }
  60
  61 diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
  62 index defa962a8e15..7bf1683e81af 100644
  63 --- a/fs/jbd2/journal.c
  64 +++ b/fs/jbd2/journal.c
  65 @@ -2587,7 +2587,7 @@ void jbd2_journal_release_jbd_inode(journal_t *journal,
  66  restart:
  67         spin_lock(&journal->j_list_lock);
  68         /* Is commit writing out inode - we have to wait */
  69 -       if (test_bit(__JI_COMMIT_RUNNING, &jinode->i_flags)) {
  70 +       if (jinode->i_flags & JI_COMMIT_RUNNING) {
  71                 wait_queue_head_t *wq;
  72                 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
  73                 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
  74 --
  75 2.6.2
  76
  77