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loop: replace kill_bdev with invalidate_bdev 

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: 5db470e229 ("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>
alistair/sunxi64-5.8
Zheng Bin 2020-06-18 12:21:37 +08:00 committed by Jens Axboe
parent bc163c2046
commit f4bd34b139
1 changed files with 4 additions and 4 deletions
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8
drivers/block/loop.c
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@ -1368,14 +1368,14 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
lo->lo_sizelimit != info->lo_sizelimit) {
size_changed = true;
sync_blockdev(lo->lo_device);
kill_bdev(lo->lo_device);
invalidate_bdev(lo->lo_device);
}
/* I/O need to be drained during transfer transition */
blk_mq_freeze_queue(lo->lo_queue);
if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
/* If any pages were dirtied after kill_bdev(), try again */
/* If any pages were dirtied after invalidate_bdev(), try again */
err = -EAGAIN;
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
__func__, lo->lo_number, lo->lo_file_name,
@ -1615,11 +1615,11 @@ 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",