[PATCH 2/3] xfs: clean up the metadata validation in xfs_swap_extent_rmap

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Bail out if there's something not right with either file's fork
mappings.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_bmap_util.c |   31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)


diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index cc23a3e23e2d..2774939e176d 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1342,8 +1342,16 @@ xfs_swap_extent_rmap(
 				&nimaps, 0);
 		if (error)
 			goto out;
-		ASSERT(nimaps == 1);
-		ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
+		if (nimaps != 1 || tirec.br_startblock == DELAYSTARTBLOCK) {
+			/*
+			 * We should never get no mapping or a delalloc extent
+			 * since the donor file should have been flushed by the
+			 * caller.
+			 */
+			ASSERT(0);
+			error = -EINVAL;
+			goto out;
+		}
 
 		trace_xfs_swap_extent_rmap_remap(tip, &tirec);
 		ilen = tirec.br_blockcount;
@@ -1360,8 +1368,17 @@ xfs_swap_extent_rmap(
 					&nimaps, 0);
 			if (error)
 				goto out;
-			ASSERT(nimaps == 1);
-			ASSERT(tirec.br_startoff == irec.br_startoff);
+			if (nimaps != 1 ||
+			    tirec.br_startoff != irec.br_startoff) {
+				/*
+				 * We should never get no mapping or a mapping
+				 * for another offset, but bail out if that
+				 * ever does.
+				 */
+				ASSERT(0);
+				error = -EFSCORRUPTED;
+				goto out;
+			}
 			trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
 
 			/* Trim the extent. */
@@ -1400,11 +1417,9 @@ xfs_swap_extent_rmap(
 		offset_fsb += ilen;
 	}
 
-	tip->i_d.di_flags2 = tip_flags2;
-	return 0;
-
 out:
-	trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
+	if (error)
+		trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
 	tip->i_d.di_flags2 = tip_flags2;
 	return error;
 }