[PATCH 1/3] xfs: fix the calculation of length and end

[Shiyang Ruan]

The end should be start + length - 1.  Also fix the calculation of the
length when seeking for intersection of notify range and device.

Signed-off-by: Shiyang Ruan <ruansy.f...@fujitsu.com>
Reviewed-by: Darrick J. Wong <djw...@kernel.org>
---
 fs/xfs/xfs_notify_failure.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_notify_failure.c b/fs/xfs/xfs_notify_failure.c
index c4078d0ec108..3830f908e215 100644
--- a/fs/xfs/xfs_notify_failure.c
+++ b/fs/xfs/xfs_notify_failure.c
@@ -114,7 +114,7 @@ xfs_dax_notify_ddev_failure(
        int                     error = 0;
        xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, daddr);
        xfs_agnumber_t          agno = XFS_FSB_TO_AGNO(mp, fsbno);
-       xfs_fsblock_t           end_fsbno = XFS_DADDR_TO_FSB(mp, daddr + bblen);
+       xfs_fsblock_t           end_fsbno = XFS_DADDR_TO_FSB(mp, daddr + bblen 
- 1);
        xfs_agnumber_t          end_agno = XFS_FSB_TO_AGNO(mp, end_fsbno);
 
        error = xfs_trans_alloc_empty(mp, &tp);
@@ -210,7 +210,7 @@ xfs_dax_notify_failure(
        ddev_end = ddev_start + bdev_nr_bytes(mp->m_ddev_targp->bt_bdev) - 1;
 
        /* Ignore the range out of filesystem area */
-       if (offset + len < ddev_start)
+       if (offset + len - 1 < ddev_start)
                return -ENXIO;
        if (offset > ddev_end)
                return -ENXIO;
@@ -222,8 +222,8 @@ xfs_dax_notify_failure(
                len -= ddev_start - offset;
                offset = 0;
        }
-       if (offset + len > ddev_end)
-               len -= ddev_end - offset;
+       if (offset + len - 1 > ddev_end)
+               len -= offset + len - 1 - ddev_end;
 
        return xfs_dax_notify_ddev_failure(mp, BTOBB(offset), BTOBB(len),
                        mf_flags);
-- 
2.37.3