[PATCH 6.6 635/638] dm-integrity: align the outgoing bio in integrity_recheck

Sasha Levin
2024-03-24T23:11:46Z

From: Mikulas Patocka <mpatocka@redhat.com>

[ Upstream commit b4d78cfeb30476239cf08f4f40afc095c173d6e3 ]

It is possible to set up dm-integrity with smaller sector size than
the logical sector size of the underlying device. In this situation,
dm-integrity guarantees that the outgoing bios have the same alignment as
incoming bios (so, if you create a filesystem with 4k block size,
dm-integrity would send 4k-aligned bios to the underlying device).

This guarantee was broken when integrity_recheck was implemented.
integrity_recheck sends bio that is aligned to ic->sectors_per_block. So
if we set up integrity with 512-byte sector size on a device with logical
block size 4k, we would be sending unaligned bio. This triggered a bug in
one of our internal tests.

This commit fixes it by determining the actual alignment of the
incoming bio and then makes sure that the outgoing bio in
integrity_recheck has the same alignment.

Fixes: c88f5e553fe3 ("dm-integrity: recheck the integrity tag after a failure")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/md/dm-integrity.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 71c3b891c4df5..e7cd27e387df1 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1709,7 +1709,6 @@ static noinline void integrity_recheck(struct dm_integrity_io *dio, char *checks
struct bio_vec bv;
sector_t sector, logical_sector, area, offset;
struct page *page;
- void *buffer;

get_area_and_offset(ic, dio->range.logical_sector, &area, &offset);
dio->metadata_block = get_metadata_sector_and_offset(ic, area, offset,
@@ -1718,13 +1717,14 @@ static noinline void integrity_recheck(struct dm_integrity_io *dio, char *checks
logical_sector = dio->range.logical_sector;

page = mempool_alloc(&ic->recheck_pool, GFP_NOIO);
- buffer = page_to_virt(page);

__bio_for_each_segment(bv, bio, iter, dio->bio_details.bi_iter) {
unsigned pos = 0;

do {
+ sector_t alignment;
char *mem;
+ char *buffer = page_to_virt(page);
int r;
struct dm_io_request io_req;
struct dm_io_region io_loc;
@@ -1737,6 +1737,14 @@ static noinline void integrity_recheck(struct dm_integrity_io *dio, char *checks
io_loc.sector = sector;
io_loc.count = ic->sectors_per_block;

+ /* Align the bio to logical block size */
+ alignment = dio->range.logical_sector | bio_sectors(bio) | (PAGE_SIZE >> SECTOR_SHIFT);
+ alignment &= -alignment;
+ io_loc.sector = round_down(io_loc.sector, alignment);
+ io_loc.count += sector - io_loc.sector;
+ buffer += (sector - io_loc.sector) << SECTOR_SHIFT;
+ io_loc.count = round_up(io_loc.count, alignment);
+
r = dm_io(&io_req, 1, &io_loc, NULL, IOPRIO_DEFAULT);
if (unlikely(r)) {
dio->bi_status = errno_to_blk_status(r);
--
2.43.0