From: Michael Lass bevan@bi-co.net
commit 51b86f9a8d1c4bb4e3862ee4b4c5f46072f7520d upstream.
Commit 61697a6abd24 ("dm: eliminate 'split_discard_bios' flag from DM target interface") incorrectly removed code from __send_changing_extent_only() that is required to impose a per-target IO boundary on IO that exceeds max_io_len_target_boundary(). Otherwise "special" IO (e.g. DISCARD, WRITE SAME, WRITE ZEROES) can write beyond where allowed.
Fix this by restoring the max_io_len_target_boundary() limit in __send_changing_extent_only()
Fixes: 61697a6abd24 ("dm: eliminate 'split_discard_bios' flag from DM target interface") Cc: stable@vger.kernel.org # 5.1+ Signed-off-by: Michael Lass bevan@bi-co.net Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1467,7 +1467,7 @@ static unsigned get_num_write_zeroes_bio static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti, unsigned num_bios) { - unsigned len = ci->sector_count; + unsigned len;
/* * Even though the device advertised support for this type of @@ -1478,6 +1478,8 @@ static int __send_changing_extent_only(s if (!num_bios) return -EOPNOTSUPP;
+ len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); + __send_duplicate_bios(ci, ti, num_bios, &len);
ci->sector += len;