linux/fs/btrfs/tree-checker.h
Qu Wenruo 69fc6cbbac btrfs: tree-checker: Fix false panic for sanity test
[BUG]
If we run btrfs with CONFIG_BTRFS_FS_RUN_SANITY_TESTS=y, it will
instantly cause kernel panic like:

------
...
assertion failed: 0, file: fs/btrfs/disk-io.c, line: 3853
...
Call Trace:
 btrfs_mark_buffer_dirty+0x187/0x1f0 [btrfs]
 setup_items_for_insert+0x385/0x650 [btrfs]
 __btrfs_drop_extents+0x129a/0x1870 [btrfs]
...
-----

[Cause]
Btrfs will call btrfs_check_leaf() in btrfs_mark_buffer_dirty() to check
if the leaf is valid with CONFIG_BTRFS_FS_RUN_SANITY_TESTS=y.

However quite some btrfs_mark_buffer_dirty() callers(*) don't really
initialize its item data but only initialize its item pointers, leaving
item data uninitialized.

This makes tree-checker catch uninitialized data as error, causing
such panic.

*: These callers include but not limited to
setup_items_for_insert()
btrfs_split_item()
btrfs_expand_item()

[Fix]
Add a new parameter @check_item_data to btrfs_check_leaf().
With @check_item_data set to false, item data check will be skipped and
fallback to old btrfs_check_leaf() behavior.

So we can still get early warning if we screw up item pointers, and
avoid false panic.

Cc: Filipe Manana <fdmanana@gmail.com>
Reported-by: Lakshmipathi.G <lakshmipathi.g@gmail.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-28 14:59:09 +01:00

39 lines
1.1 KiB
C

/*
* Copyright (C) Qu Wenruo 2017. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program.
*/
#ifndef __BTRFS_TREE_CHECKER__
#define __BTRFS_TREE_CHECKER__
#include "ctree.h"
#include "extent_io.h"
/*
* Comprehensive leaf checker.
* Will check not only the item pointers, but also every possible member
* in item data.
*/
int btrfs_check_leaf_full(struct btrfs_root *root, struct extent_buffer *leaf);
/*
* Less strict leaf checker.
* Will only check item pointers, not reading item data.
*/
int btrfs_check_leaf_relaxed(struct btrfs_root *root,
struct extent_buffer *leaf);
int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node);
#endif