The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a14e5ec66a7a66e57b24e2469f9212a78460207e Mon Sep 17 00:00:00 2001
From: Mikulas Patocka mpatocka@redhat.com Date: Tue, 23 Feb 2021 21:21:20 +0100 Subject: [PATCH] dm bufio: subtract the number of initial sectors in dm_bufio_get_device_size
dm_bufio_get_device_size returns the device size in blocks. Before returning the value, we must subtract the nubmer of starting sectors. The number of starting sectors 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 change has no effect. However, an upcoming dm-verity-fec fix needs this change.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Reviewed-by: Milan Broz gmazyland@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer snitzer@redhat.com
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index fce4cbf9529d..50f3e673729c 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1526,6 +1526,10 @@ EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); 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