[PATCH 7/6] XFS: Add trace points for per-ag refcount debugging.

Dave Chinner
2009-12-20T04:27:36Z

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>
---
fs/xfs/linux-2.6/xfs_trace.h | 27 +++++++++++++++++++++++++++
fs/xfs/xfs_ag.h | 2 ++
fs/xfs/xfs_mount.c | 34 ++++++++++++++++++++++++++++++++++
fs/xfs/xfs_mount.h | 25 ++-----------------------
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 d4ded59..5ec1475 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -33,6 +33,33 @@ struct xfs_dquot;
struct xlog_ticket;
struct log;

+#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) \
TRACE_EVENT(name, \
TP_PROTO(struct xfs_attr_list_context *ctx), \
diff --git a/fs/xfs/xfs_ag.h b/fs/xfs/xfs_ag.h
index 18ae43f..963bc27 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 1d00f7f..223d9c3 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 16b2212..e62fd1c 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