Commit 51b86f9a authored May 21, 2019 by Michael Lass Committed by Mike Snitzer May 21, 2019

dm: make sure to obey max_io_len_target_boundary



Commit 61697a6a ("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: 61697a6a ("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>

parent 8454fca4

drivers/md/dm.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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;

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