3 files changed, 25 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index d2f4ab1..7eb9970 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4057,6 +4057,17 @@ xfs_trim_extent(
 	}
 }
 
+/* trim extent to within eof */
+void
+xfs_trim_extent_eof(
+	struct xfs_bmbt_irec	*irec,
+	struct xfs_inode	*ip)
+
+{
+	xfs_trim_extent(irec, 0, XFS_B_TO_FSB(ip->i_mount,
+					      i_size_read(VFS_I(ip))));
+}
+
 /*
  * Trim the returned map to the required bounds
  */
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index db53ac7f..f1446d1 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -196,6 +196,7 @@ void	xfs_bmap_trace_exlist(struct xfs_inode *ip, xfs_extnum_t cnt,
 
 void	xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
 		xfs_filblks_t len);
+void	xfs_trim_extent_eof(struct xfs_bmbt_irec *, struct xfs_inode *);
 int	xfs_bmap_add_attrfork(struct xfs_inode *ip, int size, int rsvd);
 void	xfs_bmap_local_to_extents_empty(struct xfs_inode *ip, int whichfork);
 void	xfs_bmap_add_free(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index c2dee43..d31cd1e 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -438,6 +438,19 @@ xfs_imap_valid(
 {
 	offset >>= inode->i_blkbits;
 
+	/*
+	 * We have to make sure the cached mapping is within EOF to protect
+	 * against eofblocks trimming on file release leaving us with a stale
+	 * mapping. Otherwise, a page for a subsequent file extending buffered
+	 * write could get picked up by this writeback cycle and written to the
+	 * wrong blocks.
+	 *
+	 * Note that what we really want here is a generic mapping invalidation
+	 * mechanism to protect us from arbitrary extent modifying contexts, not
+	 * just eofblocks.
+	 */
+	xfs_trim_extent_eof(imap, XFS_I(inode));
+
 	return offset >= imap->br_startoff &&
 		offset < imap->br_startoff + imap->br_blockcount;
 }