xfs: convert xfs_iwalk to use perag references

Rather than manually walking the ags and passing agnunbers around,
pass the perag for the AG we are currently working on around in the
iwalk structure.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/libxfs/xfs_ag.h

@@ -117,19 +117,23 @@ void	xfs_perag_put(struct xfs_perag *pag);
 /*
  * Perag iteration APIs
  */
-#define for_each_perag(mp, next_agno, pag) \
-	for ((next_agno) = 0, (pag) = xfs_perag_get((mp), 0); \
+#define for_each_perag_from(mp, next_agno, pag) \
+	for ((pag) = xfs_perag_get((mp), (next_agno)); \
 		(pag) != NULL; \
 		(next_agno) = (pag)->pag_agno + 1, \
 		xfs_perag_put(pag), \
 		(pag) = xfs_perag_get((mp), (next_agno)))
 
-#define for_each_perag_tag(mp, next_agno, pag, tag) \
-	for ((next_agno) = 0, (pag) = xfs_perag_get_tag((mp), 0, (tag)); \
+#define for_each_perag(mp, agno, pag) \
+	(agno) = 0; \
+	for_each_perag_from((mp), (agno), (pag))
+
+#define for_each_perag_tag(mp, agno, pag, tag) \
+	for ((agno) = 0, (pag) = xfs_perag_get_tag((mp), 0, (tag)); \
 		(pag) != NULL; \
-		(next_agno) = (pag)->pag_agno + 1, \
+		(agno) = (pag)->pag_agno + 1, \
 		xfs_perag_put(pag), \
-		(pag) = xfs_perag_get_tag((mp), (next_agno), (tag)))
+		(pag) = xfs_perag_get_tag((mp), (agno), (tag)))
 
 struct aghdr_init_data {
 	/* per ag data */

fs/xfs/xfs_iwalk.c

@@ -21,6 +21,7 @@
 #include "xfs_health.h"
 #include "xfs_trans.h"
 #include "xfs_pwork.h"
+#include "xfs_ag.h"
 
 /*
  * Walking Inodes in the Filesystem
@@ -51,6 +52,7 @@ struct xfs_iwalk_ag {
 
 	struct xfs_mount		*mp;
 	struct xfs_trans		*tp;
+	struct xfs_perag		*pag;
 
 	/* Where do we start the traversal? */
 	xfs_ino_t			startino;
@@ -90,7 +92,7 @@ struct xfs_iwalk_ag {
 STATIC void
 xfs_iwalk_ichunk_ra(
 	struct xfs_mount		*mp,
-	xfs_agnumber_t			agno,
+	struct xfs_perag		*pag,
 	struct xfs_inobt_rec_incore	*irec)
 {
 	struct xfs_ino_geometry		*igeo = M_IGEO(mp);
@@ -106,7 +108,7 @@ xfs_iwalk_ichunk_ra(
 
 		imask = xfs_inobt_maskn(i, igeo->inodes_per_cluster);
 		if (imask & ~irec->ir_free) {
-			xfs_btree_reada_bufs(mp, agno, agbno,
+			xfs_btree_reada_bufs(mp, pag->pag_agno, agbno,
 					igeo->blocks_per_cluster,
 					&xfs_inode_buf_ops);
 		}
@@ -178,22 +180,21 @@ xfs_iwalk_ag_recs(
 {
 	struct xfs_mount	*mp = iwag->mp;
 	struct xfs_trans	*tp = iwag->tp;
+	struct xfs_perag	*pag = iwag->pag;
 	xfs_ino_t		ino;
 	unsigned int		i, j;
-	xfs_agnumber_t			agno;
 	int			error;
 
-	agno = XFS_INO_TO_AGNO(mp, iwag->startino);
 	for (i = 0; i < iwag->nr_recs; i++) {
 		struct xfs_inobt_rec_incore	*irec = &iwag->recs[i];
 
-		trace_xfs_iwalk_ag_rec(mp, agno, irec);
+		trace_xfs_iwalk_ag_rec(mp, pag->pag_agno, irec);
 
 		if (xfs_pwork_want_abort(&iwag->pwork))
 			return 0;
 
 		if (iwag->inobt_walk_fn) {
-			error = iwag->inobt_walk_fn(mp, tp, agno, irec,
+			error = iwag->inobt_walk_fn(mp, tp, pag->pag_agno, irec,
 					iwag->data);
 			if (error)
 				return error;
@@ -211,7 +212,8 @@ xfs_iwalk_ag_recs(
 				continue;
 
 			/* Otherwise call our function. */
-			ino = XFS_AGINO_TO_INO(mp, agno, irec->ir_startino + j);
+			ino = XFS_AGINO_TO_INO(mp, pag->pag_agno,
+						irec->ir_startino + j);
 			error = iwag->iwalk_fn(mp, tp, ino, iwag->data);
 			if (error)
 				return error;
@@ -257,7 +259,6 @@ xfs_iwalk_del_inobt(
 STATIC int
 xfs_iwalk_ag_start(
 	struct xfs_iwalk_ag	*iwag,
-	xfs_agnumber_t		agno,
 	xfs_agino_t		agino,
 	struct xfs_btree_cur	**curpp,
 	struct xfs_buf		**agi_bpp,
@@ -265,12 +266,14 @@ xfs_iwalk_ag_start(
 {
 	struct xfs_mount	*mp = iwag->mp;
 	struct xfs_trans	*tp = iwag->tp;
+	struct xfs_perag	*pag = iwag->pag;
 	struct xfs_inobt_rec_incore *irec;
 	int			error;
 
 	/* Set up a fresh cursor and empty the inobt cache. */
 	iwag->nr_recs = 0;
-	error = xfs_inobt_cur(mp, tp, agno, XFS_BTNUM_INO, curpp, agi_bpp);
+	error = xfs_inobt_cur(mp, tp, pag->pag_agno, XFS_BTNUM_INO,
+				curpp, agi_bpp);
 	if (error)
 		return error;
 
@@ -304,7 +307,7 @@ xfs_iwalk_ag_start(
 	if (XFS_IS_CORRUPT(mp, *has_more != 1))
 		return -EFSCORRUPTED;
 
-	iwag->lastino = XFS_AGINO_TO_INO(mp, agno,
+	iwag->lastino = XFS_AGINO_TO_INO(mp, pag->pag_agno,
 				irec->ir_startino + XFS_INODES_PER_CHUNK - 1);
 
 	/*
@@ -345,7 +348,6 @@ xfs_iwalk_ag_start(
 STATIC int
 xfs_iwalk_run_callbacks(
 	struct xfs_iwalk_ag		*iwag,
-	xfs_agnumber_t			agno,
 	struct xfs_btree_cur		**curpp,
 	struct xfs_buf			**agi_bpp,
 	int				*has_more)
@@ -376,7 +378,8 @@ xfs_iwalk_run_callbacks(
 		return 0;
 
 	/* ...and recreate the cursor just past where we left off. */
-	error = xfs_inobt_cur(mp, tp, agno, XFS_BTNUM_INO, curpp, agi_bpp);
+	error = xfs_inobt_cur(mp, tp, iwag->pag->pag_agno, XFS_BTNUM_INO,
+				curpp, agi_bpp);
 	if (error)
 		return error;
 
@@ -390,17 +393,17 @@ xfs_iwalk_ag(
 {
 	struct xfs_mount		*mp = iwag->mp;
 	struct xfs_trans		*tp = iwag->tp;
+	struct xfs_perag		*pag = iwag->pag;
 	struct xfs_buf			*agi_bp = NULL;
 	struct xfs_btree_cur		*cur = NULL;
-	xfs_agnumber_t			agno;
 	xfs_agino_t			agino;
 	int				has_more;
 	int				error = 0;
 
 	/* Set up our cursor at the right place in the inode btree. */
-	agno = XFS_INO_TO_AGNO(mp, iwag->startino);
+	ASSERT(pag->pag_agno == XFS_INO_TO_AGNO(mp, iwag->startino));
 	agino = XFS_INO_TO_AGINO(mp, iwag->startino);
-	error = xfs_iwalk_ag_start(iwag, agno, agino, &cur, &agi_bp, &has_more);
+	error = xfs_iwalk_ag_start(iwag, agino, &cur, &agi_bp, &has_more);
 
 	while (!error && has_more) {
 		struct xfs_inobt_rec_incore	*irec;
@@ -417,7 +420,7 @@ xfs_iwalk_ag(
 			break;
 
 		/* Make sure that we always move forward. */
-		rec_fsino = XFS_AGINO_TO_INO(mp, agno, irec->ir_startino);
+		rec_fsino = XFS_AGINO_TO_INO(mp, pag->pag_agno, irec->ir_startino);
 		if (iwag->lastino != NULLFSINO &&
 		    XFS_IS_CORRUPT(mp, iwag->lastino >= rec_fsino)) {
 			error = -EFSCORRUPTED;
@@ -438,7 +441,7 @@ xfs_iwalk_ag(
 		 * walking the inodes.
 		 */
 		if (iwag->iwalk_fn)
-			xfs_iwalk_ichunk_ra(mp, agno, irec);
+			xfs_iwalk_ichunk_ra(mp, pag, irec);
 
 		/*
 		 * If there's space in the buffer for more records, increment
@@ -458,15 +461,14 @@ xfs_iwalk_ag(
 		 * we would be if we had been able to increment like above.
 		 */
 		ASSERT(has_more);
-		error = xfs_iwalk_run_callbacks(iwag, agno, &cur, &agi_bp,
-				&has_more);
+		error = xfs_iwalk_run_callbacks(iwag, &cur, &agi_bp, &has_more);
 	}
 
 	if (iwag->nr_recs == 0 || error)
 		goto out;
 
 	/* Walk the unprocessed records in the cache. */
-	error = xfs_iwalk_run_callbacks(iwag, agno, &cur, &agi_bp, &has_more);
+	error = xfs_iwalk_run_callbacks(iwag, &cur, &agi_bp, &has_more);
 
 out:
 	xfs_iwalk_del_inobt(tp, &cur, &agi_bp, error);
@@ -555,6 +557,7 @@ xfs_iwalk(
 		.pwork		= XFS_PWORK_SINGLE_THREADED,
 		.lastino	= NULLFSINO,
 	};
+	struct xfs_perag	*pag;
 	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, startino);
 	int			error;
 
@@ -565,15 +568,19 @@ xfs_iwalk(
 	if (error)
 		return error;
 
-	for (; agno < mp->m_sb.sb_agcount; agno++) {
+	for_each_perag_from(mp, agno, pag) {
+		iwag.pag = pag;
 		error = xfs_iwalk_ag(&iwag);
 		if (error)
 			break;
 		iwag.startino = XFS_AGINO_TO_INO(mp, agno + 1, 0);
 		if (flags & XFS_INOBT_WALK_SAME_AG)
 			break;
+		iwag.pag = NULL;
 	}
 
+	if (iwag.pag)
+		xfs_perag_put(pag);
 	xfs_iwalk_free(&iwag);
 	return error;
 }
@@ -598,6 +605,7 @@ xfs_iwalk_ag_work(
 	error = xfs_iwalk_ag(iwag);
 	xfs_iwalk_free(iwag);
 out:
+	xfs_perag_put(iwag->pag);
 	kmem_free(iwag);
 	return error;
 }
@@ -617,6 +625,7 @@ xfs_iwalk_threaded(
 	void			*data)
 {
 	struct xfs_pwork_ctl	pctl;
+	struct xfs_perag	*pag;
 	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, startino);
 	int			error;
 
@@ -627,7 +636,7 @@ xfs_iwalk_threaded(
 	if (error)
 		return error;
 
-	for (; agno < mp->m_sb.sb_agcount; agno++) {
+	for_each_perag_from(mp, agno, pag) {
 		struct xfs_iwalk_ag	*iwag;
 
 		if (xfs_pwork_ctl_want_abort(&pctl))
@@ -635,17 +644,25 @@ xfs_iwalk_threaded(
 
 		iwag = kmem_zalloc(sizeof(struct xfs_iwalk_ag), 0);
 		iwag->mp = mp;
+
+		/*
+		 * perag is being handed off to async work, so take another
+		 * reference for the async work to release.
+		 */
+		atomic_inc(&pag->pag_ref);
+		iwag->pag = pag;
 		iwag->iwalk_fn = iwalk_fn;
 		iwag->data = data;
 		iwag->startino = startino;
 		iwag->sz_recs = xfs_iwalk_prefetch(inode_records);
 		iwag->lastino = NULLFSINO;
 		xfs_pwork_queue(&pctl, &iwag->pwork);
-		startino = XFS_AGINO_TO_INO(mp, agno + 1, 0);
+		startino = XFS_AGINO_TO_INO(mp, pag->pag_agno + 1, 0);
 		if (flags & XFS_INOBT_WALK_SAME_AG)
 			break;
 	}
-
+	if (pag)
+		xfs_perag_put(pag);
 	if (polled)
 		xfs_pwork_poll(&pctl);
 	return xfs_pwork_destroy(&pctl);
@@ -715,6 +732,7 @@ xfs_inobt_walk(
 		.pwork		= XFS_PWORK_SINGLE_THREADED,
 		.lastino	= NULLFSINO,
 	};
+	struct xfs_perag	*pag;
 	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, startino);
 	int			error;
 
@@ -725,15 +743,19 @@ xfs_inobt_walk(
 	if (error)
 		return error;
 
-	for (; agno < mp->m_sb.sb_agcount; agno++) {
+	for_each_perag_from(mp, agno, pag) {
+		iwag.pag = pag;
 		error = xfs_iwalk_ag(&iwag);
 		if (error)
 			break;
-		iwag.startino = XFS_AGINO_TO_INO(mp, agno + 1, 0);
+		iwag.startino = XFS_AGINO_TO_INO(mp, pag->pag_agno + 1, 0);
 		if (flags & XFS_INOBT_WALK_SAME_AG)
 			break;
+		iwag.pag = NULL;
 	}
 
+	if (iwag.pag)
+		xfs_perag_put(pag);
 	xfs_iwalk_free(&iwag);
 	return error;
 }