From: Zheng Bin zhengbin13@huawei.com
commit f4bd34b139a3fa2808c4205f12714c65e1548c6c upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/block/loop.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 57ed6b70d2950..565e35e69f249 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1284,7 +1284,7 @@ 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 */ @@ -1558,12 +1558,12 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
if (lo->lo_queue->limits.logical_block_size != arg) { 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_queue->limits.logical_block_size != arg && lo->lo_device->bd_inode->i_mapping->nrpages) { err = -EAGAIN;