From 51b86f9a8d1c4bb4e3862ee4b4c5f46072f7520d Mon Sep 17 00:00:00 2001 From: Michael Lass Date: Tue, 21 May 2019 21:58:07 +0200 Subject: [PATCH] dm: make sure to obey max_io_len_target_boundary 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 Signed-off-by: Mike Snitzer --- drivers/md/dm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1fb1333fefec..997385c1ca54 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1469,7 +1469,7 @@ static unsigned get_num_write_zeroes_bios(struct dm_target *ti) 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 @@ -1480,6 +1480,8 @@ static int __send_changing_extent_only(struct clone_info *ci, struct dm_target * 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;