@@ -553,8 +553,9 @@ static noinline int check_leaf(struct btrfs_root *root,
struct extent_buffer *leaf)
{
struct btrfs_fs_info *fs_info = root->fs_info;
+ /* No valid key type is 0, so all key should be larger than this key */
+ struct btrfs_key prev_key = {0, 0, 0};
struct btrfs_key key;
- struct btrfs_key leaf_key;
u32 nritems = btrfs_header_nritems(leaf);
int slot;
@@ -597,26 +598,21 @@ static noinline int check_leaf(struct btrfs_root *root,
if (nritems == 0)
return 0;
- /* Check the 0 item */
- if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
- BTRFS_LEAF_DATA_SIZE(fs_info)) {
- CORRUPT("invalid item offset size pair", leaf, root, 0);
- return -EIO;
- }
-
/*
- * Check to make sure each items keys are in the correct order and their
- * offsets make sense. We only have to loop through nritems-1 because
- * we check the current slot against the next slot, which verifies the
- * next slot's offset+size makes sense and that the current's slot
- * offset is correct.
+ * Check the following things to make sure this is a good leaf, and
+ * leaf users won't need to bother similar sanity check:
+ *
+ * 1) key order
+ * 2) item offset and size
+ * No overlap, no hole, all inside the leaf.
*/
- for (slot = 0; slot < nritems - 1; slot++) {
- btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
- btrfs_item_key_to_cpu(leaf, &key, slot + 1);
+ for (slot = 0; slot < nritems; slot++) {
+ u32 item_end_expected;
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
/* Make sure the keys are in the right order */
- if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
+ if (btrfs_comp_cpu_keys(&prev_key, &key) >= 0) {
CORRUPT("bad key order", leaf, root, slot);
return -EIO;
}
@@ -626,8 +622,12 @@ static noinline int check_leaf(struct btrfs_root *root,
* item data starts at the end of the leaf and grows towards the
* front.
*/
- if (btrfs_item_offset_nr(leaf, slot) !=
- btrfs_item_end_nr(leaf, slot + 1)) {
+ if (slot == 0)
+ item_end_expected = BTRFS_LEAF_DATA_SIZE(fs_info);
+ else
+ item_end_expected = btrfs_item_offset_nr(leaf,
+ slot - 1);
+ if (btrfs_item_end_nr(leaf, slot) != item_end_expected) {
CORRUPT("slot offset bad", leaf, root, slot);
return -EIO;
}
@@ -642,6 +642,10 @@ static noinline int check_leaf(struct btrfs_root *root,
CORRUPT("slot end outside of leaf", leaf, root, slot);
return -EIO;
}
+
+ prev_key.objectid = key.objectid;
+ prev_key.type = key.type;
+ prev_key.offset = key.offset;
}
return 0;
Current check_leaf() function does a good job checking key orders and item offset/size. However it only checks from slot 0 to the last but one slot, this is good but makes later expansion hard. So this refactoring iterates from slot 0 to the last slot. For key comparison, it uses a key with all 0 as initial key, so all valid key should be larger than it. And for item size/offset check, it compares current item end with previous item offset. For slot 0, use leaf end as special case. This makes later item/key offset check and item size check easier to be implemented. Signed-off-by: Qu Wenruo <quwenruo.btrfs@gmx.com> --- fs/btrfs/disk-io.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-)