1 files changed, 83 insertions, 15 deletions
diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h
index 3c748c456ed..73e2ad39743 100644
--- a/fs/xfs/xfs_trans_priv.h
+++ b/fs/xfs/xfs_trans_priv.h
@@ -44,25 +44,93 @@ xfs_log_busy_slot_t		*xfs_trans_add_busy(xfs_trans_t *tp,
                                                    xfs_extlen_t idx);
 /*
- * From xfs_trans_ail.c
+ * AIL traversal cursor.
+ *
+ * Rather than using a generation number for detecting changes in the ail, use
+ * a cursor that is protected by the ail lock. The aild cursor exists in the
+ * struct xfs_ail, but other traversals can declare it on the stack and link it
+ * to the ail list.
+ *
+ * When an object is deleted from or moved int the AIL, the cursor list is
+ * searched to see if the object is a designated cursor item. If it is, it is
+ * deleted from the cursor so that the next time the cursor is used traversal
+ * will return to the start.
+ *
+ * This means a traversal colliding with a removal will cause a restart of the
+ * list scan, rather than any insertion or deletion anywhere in the list. The
+ * low bit of the item pointer is set if the cursor has been invalidated so
+ * that we can tell the difference between invalidation and reaching the end
+ * of the list to trigger traversal restarts.
 */
-void                    xfs_trans_update_ail(struct xfs_mount *mp,
+struct xfs_ail_cursor {
-                                     struct xfs_log_item *lip, xfs_lsn_t lsn)
+        struct xfs_ail_cursor   *next;
-                                     __releases(mp->m_ail_lock);
+        struct xfs_log_item     *item;
-void                    xfs_trans_delete_ail(struct xfs_mount *mp,
+};
-                                     struct xfs_log_item *lip)
-                                     __releases(mp->m_ail_lock);
-struct xfs_log_item     *xfs_trans_first_ail(struct xfs_mount *, int *);
-struct xfs_log_item     *xfs_trans_next_ail(struct xfs_mount *,
-                                     struct xfs_log_item *, int *, int *);
+/*
+ * Private AIL structures.
+ *
+ * Eventually we need to drive the locking in here as well.
+ */
+struct xfs_ail {
+        struct xfs_mount        *xa_mount;
+        struct list_head        xa_ail;
+        uint                    xa_gen;
+        struct task_struct      *xa_task;
+        xfs_lsn_t               xa_target;
+        struct xfs_ail_cursor   xa_cursors;
+        spinlock_t              xa_lock;
+};
 /*
- * AIL push thread support
+ * From xfs_trans_ail.c
 */
-long    xfsaild_push(struct xfs_mount *, xfs_lsn_t *);
+void                    xfs_trans_ail_update(struct xfs_ail *ailp,
-void    xfsaild_wakeup(struct xfs_mount *, xfs_lsn_t);
+                                        struct xfs_log_item *lip, xfs_lsn_t lsn)
-int     xfsaild_start(struct xfs_mount *);
+                                        __releases(ailp->xa_lock);
-void    xfsaild_stop(struct xfs_mount *);
+void                    xfs_trans_ail_delete(struct xfs_ail *ailp,
+                                        struct xfs_log_item *lip)
+                                        __releases(ailp->xa_lock);
+void                    xfs_trans_ail_push(struct xfs_ail *, xfs_lsn_t);
+void                    xfs_trans_unlocked_item(struct xfs_ail *,
+                                        xfs_log_item_t *);
+xfs_lsn_t               xfs_trans_ail_tail(struct xfs_ail *ailp);
+struct xfs_log_item     *xfs_trans_ail_cursor_first(struct xfs_ail *ailp,
+                                        struct xfs_ail_cursor *cur,
+                                        xfs_lsn_t lsn);
+struct xfs_log_item     *xfs_trans_ail_cursor_next(struct xfs_ail *ailp,
+                                        struct xfs_ail_cursor *cur);
+void                    xfs_trans_ail_cursor_done(struct xfs_ail *ailp,
+                                        struct xfs_ail_cursor *cur);
+long    xfsaild_push(struct xfs_ail *, xfs_lsn_t *);
+void    xfsaild_wakeup(struct xfs_ail *, xfs_lsn_t);
+int     xfsaild_start(struct xfs_ail *);
+void    xfsaild_stop(struct xfs_ail *);
+#if BITS_PER_LONG != 64
+static inline void
+xfs_trans_ail_copy_lsn(
+        struct xfs_ail  *ailp,
+        xfs_lsn_t       *dst,
+        xfs_lsn_t       *src)
+{
+        ASSERT(sizeof(xfs_lsn_t) == 8); /* don't lock if it shrinks */
+        spin_lock(&ailp->xa_lock);
+        *dst = *src;
+        spin_unlock(&ailp->xa_lock);
+}
+#else
+static inline void
+xfs_trans_ail_copy_lsn(
+        struct xfs_ail  *ailp,
+        xfs_lsn_t       *dst,
+        xfs_lsn_t       *src)
+{
+        ASSERT(sizeof(xfs_lsn_t) == 8);
+        *dst = *src;
+}
+#endif
 #endif  /* __XFS_TRANS_PRIV_H__ */

diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h index 3c748c456ed..73e2ad39743 100644 --- a/fs/xfs/xfs_trans_priv.h +++ b/fs/xfs/xfs_trans_priv.h
@@ -44,25 +44,93 @@ xfs_log_busy_slot_t xfs_trans_add_busy(xfs_trans_t tp,
44	xfs_extlen_t idx);	44	xfs_extlen_t idx);
45		45
46	/*	46	/*
47	* From xfs_trans_ail.c	47	* AIL traversal cursor.
		48	*
		49	* Rather than using a generation number for detecting changes in the ail, use
		50	* a cursor that is protected by the ail lock. The aild cursor exists in the
		51	* struct xfs_ail, but other traversals can declare it on the stack and link it
		52	* to the ail list.
		53	*
		54	* When an object is deleted from or moved int the AIL, the cursor list is
		55	* searched to see if the object is a designated cursor item. If it is, it is
		56	* deleted from the cursor so that the next time the cursor is used traversal
		57	* will return to the start.
		58	*
		59	* This means a traversal colliding with a removal will cause a restart of the
		60	* list scan, rather than any insertion or deletion anywhere in the list. The
		61	* low bit of the item pointer is set if the cursor has been invalidated so
		62	* that we can tell the difference between invalidation and reaching the end
		63	* of the list to trigger traversal restarts.
48	*/	64	*/
49	void xfs_trans_update_ail(struct xfs_mount *mp,	65	struct xfs_ail_cursor {
50	struct xfs_log_item *lip, xfs_lsn_t lsn)	66	struct xfs_ail_cursor *next;
51	__releases(mp->m_ail_lock);	67	struct xfs_log_item *item;
52	void xfs_trans_delete_ail(struct xfs_mount *mp,	68	};
53	struct xfs_log_item *lip)
54	__releases(mp->m_ail_lock);
55	struct xfs_log_item xfs_trans_first_ail(struct xfs_mount , int *);
56	struct xfs_log_item xfs_trans_next_ail(struct xfs_mount ,
57	struct xfs_log_item , int , int *);
58		69
		70	/*
		71	* Private AIL structures.
		72	*
		73	* Eventually we need to drive the locking in here as well.
		74	*/
		75	struct xfs_ail {
		76	struct xfs_mount *xa_mount;
		77	struct list_head xa_ail;
		78	uint xa_gen;
		79	struct task_struct *xa_task;
		80	xfs_lsn_t xa_target;
		81	struct xfs_ail_cursor xa_cursors;
		82	spinlock_t xa_lock;
		83	};
59		84
60	/*	85	/*
61	* AIL push thread support	86	* From xfs_trans_ail.c
62	*/	87	*/
63	long xfsaild_push(struct xfs_mount , xfs_lsn_t );	88	void xfs_trans_ail_update(struct xfs_ail *ailp,
64	void xfsaild_wakeup(struct xfs_mount *, xfs_lsn_t);	89	struct xfs_log_item *lip, xfs_lsn_t lsn)
65	int xfsaild_start(struct xfs_mount *);	90	__releases(ailp->xa_lock);
66	void xfsaild_stop(struct xfs_mount *);	91	void xfs_trans_ail_delete(struct xfs_ail *ailp,
		92	struct xfs_log_item *lip)
		93	__releases(ailp->xa_lock);
		94	void xfs_trans_ail_push(struct xfs_ail *, xfs_lsn_t);
		95	void xfs_trans_unlocked_item(struct xfs_ail *,
		96	xfs_log_item_t *);
		97
		98	xfs_lsn_t xfs_trans_ail_tail(struct xfs_ail *ailp);
		99
		100	struct xfs_log_item xfs_trans_ail_cursor_first(struct xfs_ail ailp,
		101	struct xfs_ail_cursor *cur,
		102	xfs_lsn_t lsn);
		103	struct xfs_log_item xfs_trans_ail_cursor_next(struct xfs_ail ailp,
		104	struct xfs_ail_cursor *cur);
		105	void xfs_trans_ail_cursor_done(struct xfs_ail *ailp,
		106	struct xfs_ail_cursor *cur);
		107
		108	long xfsaild_push(struct xfs_ail , xfs_lsn_t );
		109	void xfsaild_wakeup(struct xfs_ail *, xfs_lsn_t);
		110	int xfsaild_start(struct xfs_ail *);
		111	void xfsaild_stop(struct xfs_ail *);
67		112
		113	#if BITS_PER_LONG != 64
		114	static inline void
		115	xfs_trans_ail_copy_lsn(
		116	struct xfs_ail *ailp,
		117	xfs_lsn_t *dst,
		118	xfs_lsn_t *src)
		119	{
		120	ASSERT(sizeof(xfs_lsn_t) == 8); /* don't lock if it shrinks */
		121	spin_lock(&ailp->xa_lock);
		122	dst = src;
		123	spin_unlock(&ailp->xa_lock);
		124	}
		125	#else
		126	static inline void
		127	xfs_trans_ail_copy_lsn(
		128	struct xfs_ail *ailp,
		129	xfs_lsn_t *dst,
		130	xfs_lsn_t *src)
		131	{
		132	ASSERT(sizeof(xfs_lsn_t) == 8);
		133	dst = src;
		134	}
		135	#endif
68	#endif /* __XFS_TRANS_PRIV_H__ */	136	#endif /* __XFS_TRANS_PRIV_H__ */