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btrfs-progs: Check the consistence between the parent node and child node/leaf. 

When btrfs-progs walk down the tree, it does not check whether the child
node/leaf is valid.
In fact, there is some corrupted image whose csum is all valid but
parent node points to a invalid leaf.

In my case, the parent node in fs tree point to a invalid leaf(gen 11),
whose generation(15) and first key(EXTENT_TREE ROOT_ITEM 0) is
completely invalid, and will cause BUG_ON in process_inode_item().

Unfortunately, we are unable to fix when it happens.
So we can only output meaningful error message and avoid the insane
node/leaf, which is still much better than the original BUG_ON().

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
master
Qu Wenruo 2014-10-06 14:31:21 +08:00 committed by David Sterba
parent 935457f164
commit 0cf497719c
1 changed files with 55 additions and 0 deletions
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55
cmds-check.c
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@ -1335,6 +1335,56 @@ static void reada_walk_down(struct btrfs_root *root,
}
}
/*
* Check the child node/leaf by the following condition:
* 1. the first item key of the node/leaf should be the same with the one
* in parent.
* 2. block in parent node should match the child node/leaf.
* 3. generation of parent node and child's header should be consistent.
*
* Or the child node/leaf pointed by the key in parent is not valid.
*
* We hope to check leaf owner too, but since subvol may share leaves,
* which makes leaf owner check not so strong, key check should be
* sufficient enough for that case.
*/
static int check_child_node(struct btrfs_root *root,
struct extent_buffer *parent, int slot,
struct extent_buffer *child)
{
struct btrfs_key parent_key;
struct btrfs_key child_key;
int ret = 0;
btrfs_node_key_to_cpu(parent, &parent_key, slot);
if (btrfs_header_level(child) == 0)
btrfs_item_key_to_cpu(child, &child_key, 0);
else
btrfs_node_key_to_cpu(child, &child_key, 0);
if (memcmp(&parent_key, &child_key, sizeof(parent_key))) {
ret = -EINVAL;
fprintf(stderr,
"Wrong key of child node/leaf, wanted: (%llu, %u, %llu), have: (%llu, %u, %llu)\n",
parent_key.objectid, parent_key.type, parent_key.offset,
child_key.objectid, child_key.type, child_key.offset);
}
if (btrfs_header_bytenr(child) != btrfs_node_blockptr(parent, slot)) {
ret = -EINVAL;
fprintf(stderr, "Wrong block of child node/leaf, wanted: %llu, have: %llu\n",
btrfs_node_blockptr(parent, slot),
btrfs_header_bytenr(child));
}
if (btrfs_node_ptr_generation(parent, slot) !=
btrfs_header_generation(child)) {
ret = -EINVAL;
fprintf(stderr, "Wrong generation of child node/leaf, wanted: %llu, have: %llu\n",
btrfs_header_generation(child),
btrfs_node_ptr_generation(parent, slot));
}
return ret;
}
static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
struct walk_control *wc, int *level)
{
@ -1410,6 +1460,11 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
}
}
ret = check_child_node(root, cur, path->slots[*level], next);
if (ret) {
err = ret;
goto out;
}
*level = *level - 1;
free_extent_buffer(path->nodes[*level]);
path->nodes[*level] = next;