xfs: don't allow insert-range to shift extents past the maximum offset

Zorro Lang reports that generic/485 blows an assert on a filesystem with
512 byte blocks.  The test tries to fallocate a post-eof extent at the
maximum file size and calls insert range to shift the extents right by
two blocks.  On a 512b block filesystem this causes startoff to overflow
the 54-bit startoff field, leading to the assert.

Therefore, always check the rightmost extent to see if it would overflow
prior to invoking the insert range machinery.

Reported-by: [email protected]
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200137
Signed-off-by: Darrick J. Wong <[email protected]>
Reviewed-by: Allison Henderson <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>

0 files changed, 0 insertions, 0 deletions