xfs: make for_each_perag... a first class citizen

for_each_perag_tag() is defined in xfs_icache.c for local use.
Promote this to xfs_ag.h and define equivalent iteration functions
so that we can use them to iterate AGs instead to replace open coded
perag walks and perag lookups.

We also convert as many of the straight forward open coded AG walks
to use these iterators as possible. Anything that is not a direct
conversion to an iterator is ignored and will be updated in future
commits.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 15 insertions, 25 deletions

diff --git a/fs/xfs/scrub/fscounters.c b/fs/xfs/scrub/fscounters.c
index 453ae9adf94c..fd7941e04ae1 100644
--- a/fs/xfs/scrub/fscounters.c
+++ b/fs/xfs/scrub/fscounters.c
@@ -71,11 +71,11 @@ xchk_fscount_warmup(
 	xfs_agnumber_t		agno;
 	int			error = 0;
 
-	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
-		pag = xfs_perag_get(mp, agno);
-
+	for_each_perag(mp, agno, pag) {
+		if (xchk_should_terminate(sc, &error))
+			break;
 		if (pag->pagi_init && pag->pagf_init)
-			goto next_loop_perag;
+			continue;
 
 		/* Lock both AG headers. */
 		error = xfs_ialloc_read_agi(mp, sc->tp, agno, &agi_bp);
@@ -89,21 +89,15 @@ xchk_fscount_warmup(
 		 * These are supposed to be initialized by the header read
 		 * function.
 		 */
-		error = -EFSCORRUPTED;
-		if (!pag->pagi_init || !pag->pagf_init)
+		if (!pag->pagi_init || !pag->pagf_init) {
+			error = -EFSCORRUPTED;
 			break;
+		}
 
 		xfs_buf_relse(agf_bp);
 		agf_bp = NULL;
 		xfs_buf_relse(agi_bp);
 		agi_bp = NULL;
-next_loop_perag:
-		xfs_perag_put(pag);
-		pag = NULL;
-		error = 0;
-
-		if (xchk_should_terminate(sc, &error))
-			break;
 	}
 
 	if (agf_bp)
@@ -196,13 +190,14 @@ retry:
 	fsc->ifree = 0;
 	fsc->fdblocks = 0;
 
-	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
-		pag = xfs_perag_get(mp, agno);
+	for_each_perag(mp, agno, pag) {
+		if (xchk_should_terminate(sc, &error))
+			break;
 
 		/* This somehow got unset since the warmup? */
 		if (!pag->pagi_init || !pag->pagf_init) {
-			xfs_perag_put(pag);
-			return -EFSCORRUPTED;
+			error = -EFSCORRUPTED;
+			break;
 		}
 
 		/* Count all the inodes */
@@ -216,10 +211,8 @@ retry:
 			fsc->fdblocks += pag->pagf_btreeblks;
 		} else {
 			error = xchk_fscount_btreeblks(sc, fsc, agno);
-			if (error) {
-				xfs_perag_put(pag);
+			if (error)
 				break;
-			}
 		}
 
 		/*
@@ -229,12 +222,9 @@ retry:
 		fsc->fdblocks -= pag->pag_meta_resv.ar_reserved;
 		fsc->fdblocks -= pag->pag_rmapbt_resv.ar_orig_reserved;
 
-		xfs_perag_put(pag);
-
-		if (xchk_should_terminate(sc, &error))
-			break;
 	}
-
+	if (pag)
+		xfs_perag_put(pag);
 	if (error)
 		return error;