commit b42db0860e13067fcc7cbfba3966c9e652668bbc
Author: Eric Sandeen <sandeen@sandeen.net>
Date:   Mon Apr 16 23:06:53 2018 -0700

    xfs: enhance dinode verifier

    Add several more validations to xfs_dinode_verify:

    - For LOCAL data fork formats, di_nextents must be 0.
    - For LOCAL attr fork formats, di_anextents must be 0.
    - For inodes with no attr fork offset,
      - format must be XFS_DINODE_FMT_EXTENTS if set at all
      - di_anextents must be 0.

    Thanks to dchinner for pointing out a couple related checks I had
    forgotten to add.

    Signed-off-by: Eric Sandeen <sandeen@redhat.com>
    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199377
    Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
    Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

[ Srinidhi Rao : Backported this fix to 4.9 ]
Signed-off-by: srinidhira0 <srinidhir@vmware.com>
---
 fs/xfs/libxfs/xfs_inode_buf.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 5872cd9..429ee58 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -456,6 +456,8 @@ xfs_dinode_verify(
                                 return false;
                         if (di_size > XFS_DFORK_DSIZE(dip, mp))
                                 return false;
+			if (dip->di_nextents)
+				return false;
                 /* fall through */
                 case XFS_DINODE_FMT_EXTENTS:
                 case XFS_DINODE_FMT_BTREE:
@@ -474,13 +476,32 @@ xfs_dinode_verify(
         if (XFS_DFORK_Q(dip)) {
                 switch (dip->di_aformat) {
                 case XFS_DINODE_FMT_LOCAL:
+			if (dip->di_anextents)
+				return false;
+		/* fall through */
                 case XFS_DINODE_FMT_EXTENTS:
                 case XFS_DINODE_FMT_BTREE:
                         break;
                 default:
                         return false;
                 }
-        }
+        } else {
+		/*
+		 * If there is no fork offset, this may be a freshly-made inode
+		 * in a new disk cluster, in which case di_aformat is zeroed.
+		 * Otherwise, such an inode must be in EXTENTS format; this goes
+		 * for freed inodes as well.
+		 */
+		switch (dip->di_aformat) {
+		case 0:
+		case XFS_DINODE_FMT_EXTENTS:
+			break;
+		default:
+			return false;
+		}
+		if (dip->di_anextents)
+			return false;
+	}
 
 
 	/* only version 3 or greater inodes are extensively verified here */
-- 
2.7.4