jbd2: Change j_state_lock to be a rwlock_t

Lockstat reports have shown that j_state_lock is a major source of
lock contention, especially on systems with more than 4 CPU cores.  So
change it to be a read/write spinlock.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 47878cf16418..9c1b92ebeb94 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -760,13 +760,13 @@ void ocfs2_set_journal_params(struct ocfs2_super *osb)
         if (osb->osb_commit_interval)
                 commit_interval = osb->osb_commit_interval;
 
-        spin_lock(&journal->j_state_lock);
+        write_lock(&journal->j_state_lock);
         journal->j_commit_interval = commit_interval;
         if (osb->s_mount_opt & OCFS2_MOUNT_BARRIER)
                 journal->j_flags |= JBD2_BARRIER;
         else
                 journal->j_flags &= ~JBD2_BARRIER;
-        spin_unlock(&journal->j_state_lock);
+        write_unlock(&journal->j_state_lock);
 }
 
 int ocfs2_journal_init(struct ocfs2_journal *journal, int *dirty)