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btrfs: tree-checker: Add ROOT_ITEM check 

This patch will introduce ROOT_ITEM check, which includes:
- Key->objectid and key->offset check
  Currently only some easy check, e.g. 0 as rootid is invalid.

- Item size check
  Root item size is fixed.

- Generation checks
  Generation, generation_v2 and last_snapshot should not be greater than
  super generation + 1

- Level and alignment check
  Level should be in [0, 7], and bytenr must be aligned to sector size.

- Flags check

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203261
Reported-by: Jungyeon Yoon <jungyeon.yoon@gmail.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2019-07-16 17:00:34 +08:00 committed by David Sterba
parent 2a28468e52
commit 259ee7754b
1 changed files with 92 additions and 0 deletions
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92
fs/btrfs/tree-checker.c
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@ -821,6 +821,95 @@ static int check_inode_item(struct extent_buffer *leaf,
return 0;
}
static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key,
int slot)
{
struct btrfs_fs_info *fs_info = leaf->fs_info;
struct btrfs_root_item ri;
const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |
BTRFS_ROOT_SUBVOL_DEAD;
/* No such tree id */
if (key->objectid == 0) {
generic_err(leaf, slot, "invalid root id 0");
return -EUCLEAN;
}
/*
* Some older kernel may create ROOT_ITEM with non-zero offset, so here
* we only check offset for reloc tree whose key->offset must be a
* valid tree.
*/
if (key->objectid == BTRFS_TREE_RELOC_OBJECTID && key->offset == 0) {
generic_err(leaf, slot, "invalid root id 0 for reloc tree");
return -EUCLEAN;
}
if (btrfs_item_size_nr(leaf, slot) != sizeof(ri)) {
generic_err(leaf, slot,
"invalid root item size, have %u expect %zu",
btrfs_item_size_nr(leaf, slot), sizeof(ri));
}
read_extent_buffer(leaf, &ri, btrfs_item_ptr_offset(leaf, slot),
sizeof(ri));
/* Generation related */
if (btrfs_root_generation(&ri) >
btrfs_super_generation(fs_info->super_copy) + 1) {
generic_err(leaf, slot,
"invalid root generation, have %llu expect (0, %llu]",
btrfs_root_generation(&ri),
btrfs_super_generation(fs_info->super_copy) + 1);
return -EUCLEAN;
}
if (btrfs_root_generation_v2(&ri) >
btrfs_super_generation(fs_info->super_copy) + 1) {
generic_err(leaf, slot,
"invalid root v2 generation, have %llu expect (0, %llu]",
btrfs_root_generation_v2(&ri),
btrfs_super_generation(fs_info->super_copy) + 1);
return -EUCLEAN;
}
if (btrfs_root_last_snapshot(&ri) >
btrfs_super_generation(fs_info->super_copy) + 1) {
generic_err(leaf, slot,
"invalid root last_snapshot, have %llu expect (0, %llu]",
btrfs_root_last_snapshot(&ri),
btrfs_super_generation(fs_info->super_copy) + 1);
return -EUCLEAN;
}
/* Alignment and level check */
if (!IS_ALIGNED(btrfs_root_bytenr(&ri), fs_info->sectorsize)) {
generic_err(leaf, slot,
"invalid root bytenr, have %llu expect to be aligned to %u",
btrfs_root_bytenr(&ri), fs_info->sectorsize);
return -EUCLEAN;
}
if (btrfs_root_level(&ri) >= BTRFS_MAX_LEVEL) {
generic_err(leaf, slot,
"invalid root level, have %u expect [0, %u]",
btrfs_root_level(&ri), BTRFS_MAX_LEVEL - 1);
return -EUCLEAN;
}
if (ri.drop_level >= BTRFS_MAX_LEVEL) {
generic_err(leaf, slot,
"invalid root level, have %u expect [0, %u]",
ri.drop_level, BTRFS_MAX_LEVEL - 1);
return -EUCLEAN;
}
/* Flags check */
if (btrfs_root_flags(&ri) & ~valid_root_flags) {
generic_err(leaf, slot,
"invalid root flags, have 0x%llx expect mask 0x%llx",
btrfs_root_flags(&ri), valid_root_flags);
return -EUCLEAN;
}
return 0;
}
/*
* Common point to switch the item-specific validation.
*/
@ -856,6 +945,9 @@ static int check_leaf_item(struct extent_buffer *leaf,
case BTRFS_INODE_ITEM_KEY:
ret = check_inode_item(leaf, key, slot);
break;
case BTRFS_ROOT_ITEM_KEY:
ret = check_root_item(leaf, key, slot);
break;
}
return ret;
}