1 files changed, 29 insertions, 18 deletions

diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
index b7b838bd4ba4..4dd52b15f09c 100644
--- a/fs/xfs/scrub/agheader.c
+++ b/fs/xfs/scrub/agheader.c
@@ -609,9 +609,16 @@ out:
 /* AGFL */
 
 struct xchk_agfl_info {
-	unsigned int		sz_entries;
+	/* Number of AGFL entries that the AGF claims are in use. */
+	unsigned int		agflcount;
+
+	/* Number of AGFL entries that we found. */
 	unsigned int		nr_entries;
+
+	/* Buffer to hold AGFL entries for extent checking. */
 	xfs_agblock_t		*entries;
+
+	struct xfs_buf		*agfl_bp;
 	struct xfs_scrub	*sc;
 };
 
@@ -641,10 +648,10 @@ xchk_agfl_block(
 	struct xfs_scrub	*sc = sai->sc;
 
 	if (xfs_verify_agbno(sc->sa.pag, agbno) &&
-	    sai->nr_entries < sai->sz_entries)
+	    sai->nr_entries < sai->agflcount)
 		sai->entries[sai->nr_entries++] = agbno;
 	else
-		xchk_block_set_corrupt(sc, sc->sa.agfl_bp);
+		xchk_block_set_corrupt(sc, sai->agfl_bp);
 
 	xchk_agfl_block_xref(sc, agbno);
 
@@ -696,19 +703,26 @@ int
 xchk_agfl(
 	struct xfs_scrub	*sc)
 {
-	struct xchk_agfl_info	sai;
+	struct xchk_agfl_info	sai = {
+		.sc		= sc,
+	};
 	struct xfs_agf		*agf;
 	xfs_agnumber_t		agno = sc->sm->sm_agno;
-	unsigned int		agflcount;
 	unsigned int		i;
 	int			error;
 
+	/* Lock the AGF and AGI so that nobody can touch this AG. */
 	error = xchk_ag_read_headers(sc, agno, &sc->sa);
 	if (!xchk_process_error(sc, agno, XFS_AGFL_BLOCK(sc->mp), &error))
-		goto out;
+		return error;
 	if (!sc->sa.agf_bp)
 		return -EFSCORRUPTED;
-	xchk_buffer_recheck(sc, sc->sa.agfl_bp);
+
+	/* Try to read the AGFL, and verify its structure if we get it. */
+	error = xfs_alloc_read_agfl(sc->sa.pag, sc->tp, &sai.agfl_bp);
+	if (!xchk_process_error(sc, agno, XFS_AGFL_BLOCK(sc->mp), &error))
+		return error;
+	xchk_buffer_recheck(sc, sai.agfl_bp);
 
 	xchk_agfl_xref(sc);
 
@@ -717,24 +731,21 @@ xchk_agfl(
 
 	/* Allocate buffer to ensure uniqueness of AGFL entries. */
 	agf = sc->sa.agf_bp->b_addr;
-	agflcount = be32_to_cpu(agf->agf_flcount);
-	if (agflcount > xfs_agfl_size(sc->mp)) {
+	sai.agflcount = be32_to_cpu(agf->agf_flcount);
+	if (sai.agflcount > xfs_agfl_size(sc->mp)) {
 		xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 		goto out;
 	}
-	memset(&sai, 0, sizeof(sai));
-	sai.sc = sc;
-	sai.sz_entries = agflcount;
-	sai.entries = kmem_zalloc(sizeof(xfs_agblock_t) * agflcount,
-			KM_MAYFAIL);
+	sai.entries = kvcalloc(sai.agflcount, sizeof(xfs_agblock_t),
+			       XCHK_GFP_FLAGS);
 	if (!sai.entries) {
 		error = -ENOMEM;
 		goto out;
 	}
 
 	/* Check the blocks in the AGFL. */
-	error = xfs_agfl_walk(sc->mp, sc->sa.agf_bp->b_addr,
-			sc->sa.agfl_bp, xchk_agfl_block, &sai);
+	error = xfs_agfl_walk(sc->mp, sc->sa.agf_bp->b_addr, sai.agfl_bp,
+			xchk_agfl_block, &sai);
 	if (error == -ECANCELED) {
 		error = 0;
 		goto out_free;
@@ -742,7 +753,7 @@ xchk_agfl(
 	if (error)
 		goto out_free;
 
-	if (agflcount != sai.nr_entries) {
+	if (sai.agflcount != sai.nr_entries) {
 		xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 		goto out_free;
 	}
@@ -758,7 +769,7 @@ xchk_agfl(
 	}
 
 out_free:
-	kmem_free(sai.entries);
+	kvfree(sai.entries);
 out:
 	return error;
 }