xfs: Convert filestreams code to use per-ag get/put routines

Use xfs_perag_get() and xfs_perag_put() in the filestreams code.

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

fs/xfs/xfs_filestream.c

@@ -140,6 +140,7 @@ _xfs_filestream_pick_ag(
 	int		flags,
 	xfs_extlen_t	minlen)
 {
+	int		streams, max_streams;
 	int		err, trylock, nscan;
 	xfs_extlen_t	longest, free, minfree, maxfree = 0;
 	xfs_agnumber_t	ag, max_ag = NULLAGNUMBER;
@@ -155,15 +156,15 @@ _xfs_filestream_pick_ag(
 	trylock = XFS_ALLOC_FLAG_TRYLOCK;
 
 	for (nscan = 0; 1; nscan++) {
-
-		TRACE_AG_SCAN(mp, ag, xfs_filestream_peek_ag(mp, ag));
-
-		pag = mp->m_perag + ag;
+		pag = xfs_perag_get(mp, ag);
+		TRACE_AG_SCAN(mp, ag, atomic_read(&pag->pagf_fstrms));
 
 		if (!pag->pagf_init) {
 			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
-			if (err && !trylock)
+			if (err && !trylock) {
+				xfs_perag_put(pag);
 				return err;
+			}
 		}
 
 		/* Might fail sometimes during the 1st pass with trylock set. */
@@ -173,6 +174,7 @@ _xfs_filestream_pick_ag(
 		/* Keep track of the AG with the most free blocks. */
 		if (pag->pagf_freeblks > maxfree) {
 			maxfree = pag->pagf_freeblks;
+			max_streams = atomic_read(&pag->pagf_fstrms);
 			max_ag = ag;
 		}
 
@@ -195,13 +197,16 @@ _xfs_filestream_pick_ag(
 
 			/* Break out, retaining the reference on the AG. */
 			free = pag->pagf_freeblks;
+			streams = atomic_read(&pag->pagf_fstrms);
+			xfs_perag_put(pag);
 			*agp = ag;
 			break;
 		}
 
 		/* Drop the reference on this AG, it's not usable. */
 		xfs_filestream_put_ag(mp, ag);
 next_ag:
+		xfs_perag_put(pag);
 		/* Move to the next AG, wrapping to AG 0 if necessary. */
 		if (++ag >= mp->m_sb.sb_agcount)
 			ag = 0;
@@ -229,6 +234,7 @@ _xfs_filestream_pick_ag(
 		if (max_ag != NULLAGNUMBER) {
 			xfs_filestream_get_ag(mp, max_ag);
 			TRACE_AG_PICK1(mp, max_ag, maxfree);
+			streams = max_streams;
 			free = maxfree;
 			*agp = max_ag;
 			break;
@@ -240,8 +246,7 @@ _xfs_filestream_pick_ag(
 		return 0;
 	}
 
-	TRACE_AG_PICK2(mp, startag, *agp, xfs_filestream_peek_ag(mp, *agp),
-			free, nscan, flags);
+	TRACE_AG_PICK2(mp, startag, *agp, streams, free, nscan, flags);
 
 	return 0;
 }

fs/xfs/xfs_filestream.h

@@ -79,28 +79,49 @@ extern ktrace_t *xfs_filestreams_trace_buf;
  * the cache that reference per-ag array elements that have since been
  * reallocated.
  */
+/*
+ * xfs_filestream_peek_ag is only used in tracing code
+ */
 static inline int
 xfs_filestream_peek_ag(
 	xfs_mount_t	*mp,
 	xfs_agnumber_t	agno)
 {
-	return atomic_read(&mp->m_perag[agno].pagf_fstrms);
+	struct xfs_perag *pag;
+	int		ret;
+
+	pag = xfs_perag_get(mp, agno);
+	ret = atomic_read(&pag->pagf_fstrms);
+	xfs_perag_put(pag);
+	return ret;
 }
 
 static inline int
 xfs_filestream_get_ag(
 	xfs_mount_t	*mp,
 	xfs_agnumber_t	agno)
 {
-	return atomic_inc_return(&mp->m_perag[agno].pagf_fstrms);
+	struct xfs_perag *pag;
+	int		ret;
+
+	pag = xfs_perag_get(mp, agno);
+	ret = atomic_inc_return(&pag->pagf_fstrms);
+	xfs_perag_put(pag);
+	return ret;
 }
 
 static inline int
 xfs_filestream_put_ag(
 	xfs_mount_t	*mp,
 	xfs_agnumber_t	agno)
 {
-	return atomic_dec_return(&mp->m_perag[agno].pagf_fstrms);
+	struct xfs_perag *pag;
+	int		ret;
+
+	pag = xfs_perag_get(mp, agno);
+	ret = atomic_dec_return(&pag->pagf_fstrms);
+	xfs_perag_put(pag);
+	return ret;
 }
 
 /* allocation selection flags */