dm-integrity: align the outgoing bio in integrity_recheck

[ 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>

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 92bed6ce17931116756f66abe9d58b27cdff020f..47cf1ab34941fdd2c74d98efa0bf4315dddf6c69 100644 (file)
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1699,7 +1699,6 @@ 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,
@@ -1708,13 +1707,14 @@ 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;
@@ -1727,6 +1727,14 @@ 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);