Hello Josef Bacik,
The patch c6100a4b4e3d: "Btrfs: replace tree->mapping with
tree->private_data" from May 5, 2017, leads to the following static
checker warning:
fs/btrfs/extent_io.c:3424 __extent_writepage_io()
error: we previously assumed 'tree->ops' could be null (see line 3334)
fs/btrfs/extent_io.c
3404 * compressed extents
3405 */
3406 if (!compressed && tree->ops &&
^^^^^^^^^
This function consistently check tree->ops before dereferencing it.
3407 tree->ops->writepage_end_io_hook)
3408 tree->ops->writepage_end_io_hook(page, cur,
3409 cur + iosize - 1,
3410 NULL, 1);
3411 else if (compressed) {
3412 /* we don't want to end_page_writeback on
3413 * a compressed extent. this happens
3414 * elsewhere
3415 */
3416 nr++;
3417 }
3418
3419 cur += iosize;
3420 pg_offset += iosize;
3421 continue;
3422 }
3423
3424 set_range_writeback(tree, cur, cur + iosize - 1);
^^^^
The patch adds a new unchecked dereference.
regards,
dan carpenter
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