dm_bufio_get_device_size returns returns the device size in blocks. Before returning the value, we must subtract the nubmer of starting sectors. The number of starting sectos may not be divisible by block size. Note that currently, no target is using dm_bufio_set_sector_offset and dm_bufio_get_device_size simultaneously, so this patch has no effect. However, an upcoming patch that fixes dm-verity-fec needs this change. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/md/dm-bufio.c | 4 ++++ 1 file changed, 4 insertions(+) Index: linux-2.6/drivers/md/dm-bufio.c =================================================================== --- linux-2.6.orig/drivers/md/dm-bufio.c 2021-01-22 17:28:39.000000000 +0100 +++ linux-2.6/drivers/md/dm-bufio.c 2021-02-23 12:35:16.000000000 +0100 @@ -1526,6 +1526,10 @@ EXPORT_SYMBOL_GPL(dm_bufio_get_block_siz sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) { sector_t s = i_size_read(c->bdev->bd_inode) >> SECTOR_SHIFT; + if (s >= c->start) + s -= c->start; + else + s = 0; if (likely(c->sectors_per_block_bits >= 0)) s >>= c->sectors_per_block_bits; else -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel