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btrfs: tree-checker: Fix false panic for sanity test

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[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>
This commit is contained in:
Qu Wenruo
2017-11-08 08:54:24 +08:00
committed by David Sterba
parent ebb70442cd
commit 69fc6cbbac
3 changed files with 43 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
fs/btrfs/tree-checker.c
View File

@@ -242,7 +242,8 @@ static int check_leaf_item(struct btrfs_root *root,
return ret;
}
int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf)
static int check_leaf(struct btrfs_root *root, struct extent_buffer *leaf,
bool check_item_data)
{
struct btrfs_fs_info *fs_info = root->fs_info;
/* No valid key type is 0, so all key should be larger than this key */
@@ -361,10 +362,15 @@ int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf)
return -EUCLEAN;
}
/* Check if the item size and content meet other criteria */
ret = check_leaf_item(root, leaf, &key, slot);
if (ret < 0)
return ret;
if (check_item_data) {
/*
* Check if the item size and content meet other
* criteria
*/
ret = check_leaf_item(root, leaf, &key, slot);
if (ret < 0)
return ret;
}
prev_key.objectid = key.objectid;
prev_key.type = key.type;
@@ -374,6 +380,17 @@ int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf)
return 0;
}
int btrfs_check_leaf_full(struct btrfs_root *root, struct extent_buffer *leaf)
{
return check_leaf(root, leaf, true);
}
int btrfs_check_leaf_relaxed(struct btrfs_root *root,
struct extent_buffer *leaf)
{
return check_leaf(root, leaf, false);
}
int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node)
{
unsigned long nr = btrfs_header_nritems(node);