[PATCH 5.7 090/265] loop: replace kill_bdev with invalidate_bdev

Sasha Levin
2020-06-29T18:36:14Z

From: Zheng Bin <zhengbin13@huawei.com>

[ Upstream commit f4bd34b139a3fa2808c4205f12714c65e1548c6c ]

When a filesystem is mounted on a loop device and on a loop ioctl
LOOP_SET_STATUS64, because of kill_bdev, buffer_head mappings are getting
destroyed.
kill_bdev
truncate_inode_pages
truncate_inode_pages_range
do_invalidatepage
block_invalidatepage
discard_buffer -->clear BH_Mapped flag

sb_bread
__bread_gfp
bh = __getblk_gfp
-->discard_buffer clear BH_Mapped flag
__bread_slow
submit_bh
submit_bh_wbc
BUG_ON(!buffer_mapped(bh)) --> hit this BUG_ON

Fixes: 5db470e229e2 ("loop: drop caches if offset or block_size are changed")
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/loop.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index da693e6a834e5..418bb4621255a 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1289,7 +1289,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit) {
sync_blockdev(lo->lo_device);
- kill_bdev(lo->lo_device);
+ invalidate_bdev(lo->lo_device);
}

/* I/O need to be drained during transfer transition */
@@ -1320,7 +1320,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)

if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit) {
- /* kill_bdev should have truncated all the pages */
+ /* invalidate_bdev should have truncated all the pages */
if (lo->lo_device->bd_inode->i_mapping->nrpages) {
err = -EAGAIN;
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
@@ -1565,11 +1565,11 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
return 0;

sync_blockdev(lo->lo_device);
- kill_bdev(lo->lo_device);
+ invalidate_bdev(lo->lo_device);

blk_mq_freeze_queue(lo->lo_queue);

- /* kill_bdev should have truncated all the pages */
+ /* invalidate_bdev should have truncated all the pages */
if (lo->lo_device->bd_inode->i_mapping->nrpages) {
err = -EAGAIN;
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
--
2.25.1