xfs: fix the calculation for "end" and "length"

The value of "end" should be "start + length - 1".

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/xfs_notify_failure.c b/fs/xfs/xfs_notify_failure.c
index c4078d0..4a9bbd3 100644 (file)
--- a/fs/xfs/xfs_notify_failure.c
+++ b/fs/xfs/xfs_notify_failure.c
@@ -114,7 +114,8 @@ 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 +211,7 @@ 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 +223,8 @@ 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 = ddev_end - offset + 1;
 
        return xfs_dax_notify_ddev_failure(mp, BTOBB(offset), BTOBB(len),
                        mf_flags);