xfs: Add trace points for per-ag refcount debugging.

[safe/jmp/linux-2.6] / fs / xfs / xfs_mount.c

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index f241fec..049dbc7 100644 (file)
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -201,6 +201,38 @@ xfs_uuid_unmount(
 
 
 /*
+ * Reference counting access wrappers to the perag structures.
+ */
+struct xfs_perag *
+xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
+{
+       struct xfs_perag        *pag;
+       int                     ref = 0;
+
+       spin_lock(&mp->m_perag_lock);
+       pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+       if (pag) {
+               ASSERT(atomic_read(&pag->pag_ref) >= 0);
+               /* catch leaks in the positive direction during testing */
+               ASSERT(atomic_read(&pag->pag_ref) < 1000);
+               ref = atomic_inc_return(&pag->pag_ref);
+       }
+       spin_unlock(&mp->m_perag_lock);
+       trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
+       return pag;
+}
+
+void
+xfs_perag_put(struct xfs_perag *pag)
+{
+       int     ref;
+
+       ASSERT(atomic_read(&pag->pag_ref) > 0);
+       ref = atomic_dec_return(&pag->pag_ref);
+       trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);
+}
+
+/*
  * Free up the resources associated with a mount structure.  Assume that
  * the structure was initially zeroed, so we can tell which fields got
  * initialized.
@@ -433,6 +465,8 @@ xfs_initialize_perag(
                        kmem_free(pag);
                        return -EEXIST;
                }
+               pag->pag_agno = index;
+               pag->pag_mount = mp;
                spin_unlock(&mp->m_perag_lock);
                radix_tree_preload_end();
        }