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

Uninline xfs_perag_{get,put} so that tracepoints can be inserted
into them to speed debugging of reference count problems.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

4 files changed, 65 insertions, 23 deletions

diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index 3353aef50530..1bb09e70b2eb 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -78,6 +78,33 @@ DECLARE_EVENT_CLASS(xfs_attr_list_class,
         )
 )
 
+#define DEFINE_PERAG_REF_EVENT(name) \
+TRACE_EVENT(name, \
+        TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount, \
+                 unsigned long caller_ip), \
+        TP_ARGS(mp, agno, refcount, caller_ip), \
+        TP_STRUCT__entry( \
+                __field(dev_t, dev) \
+                __field(xfs_agnumber_t, agno) \
+                __field(int, refcount) \
+                __field(unsigned long, caller_ip) \
+        ), \
+        TP_fast_assign( \
+                __entry->dev = mp->m_super->s_dev; \
+                __entry->agno = agno; \
+                __entry->refcount = refcount; \
+                __entry->caller_ip = caller_ip; \
+        ), \
+        TP_printk("dev %d:%d agno %u refcount %d caller %pf", \
+                  MAJOR(__entry->dev), MINOR(__entry->dev), \
+                  __entry->agno, \
+                  __entry->refcount, \
+                  (char *)__entry->caller_ip) \
+);
+
+DEFINE_PERAG_REF_EVENT(xfs_perag_get)
+DEFINE_PERAG_REF_EVENT(xfs_perag_put)
+
 #define DEFINE_ATTR_LIST_EVENT(name) \
 DEFINE_EVENT(xfs_attr_list_class, name, \
         TP_PROTO(struct xfs_attr_list_context *ctx), \
diff --git a/fs/xfs/xfs_ag.h b/fs/xfs/xfs_ag.h
index 18ae43f4255d..963bc2700bf7 100644
--- a/fs/xfs/xfs_ag.h
+++ b/fs/xfs/xfs_ag.h
@@ -197,6 +197,8 @@ typedef struct xfs_perag_busy {
 #endif
 
 typedef struct xfs_perag {
+        struct xfs_mount *pag_mount;    /* owner filesystem */
+        xfs_agnumber_t  pag_agno;       /* AG this structure belongs to */
         atomic_t        pag_ref;        /* perag reference count */
         char            pagf_init;      /* this agf's entry is initialized */
         char            pagi_init;      /* this agi's entry is initialized */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index f241fec26070..049dbc71c28e 100644
--- 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();
         }
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 16b22120b98f..e62fd1cde464 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -386,29 +386,8 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
 /*
  * perag get/put wrappers for ref counting
  */
-static inline struct xfs_perag *
-xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
-{
-        struct xfs_perag        *pag;
-
-        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);
-                atomic_inc(&pag->pag_ref);
-        }
-        spin_unlock(&mp->m_perag_lock);
-        return pag;
-}
-
-static inline void
-xfs_perag_put(struct xfs_perag *pag)
-{
-        ASSERT(atomic_read(&pag->pag_ref) > 0);
-        atomic_dec(&pag->pag_ref);
-}
+struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno);
+void    xfs_perag_put(struct xfs_perag *pag);
 
 /*
  * Per-cpu superblock locking functions