| Message ID | 20171122090325.29458-3-wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/cmds-check.c b/cmds-check.c index 644ee084cb8e..03ff89a4221c 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -2149,7 +2149,12 @@ static int need_check(struct btrfs_root *root, struct ulist *roots) struct rb_node *node; struct ulist_node *u; - if (roots->nnodes == 1) + /* + * @roots can be empty if it belongs to tree reloc tree + * In that case, we should always check the leaf, as we can't use + * the tree owner to ensure some other root will check it. + */ + if (roots->nnodes == 1 || roots->nnodes == 0) return 1; node = rb_first(&roots->root);
[BUG] v4.14 btrfs-progs can't pass new self test image with large tree reloc trees. It will fail with later "shared_block_ref_only.raw.xz" test image with NULL pointer access. [CAUSE] For image with higher (level >= 2) tree reloc tree, for function need_check() its ulist will be empty as tree reloc tree won't be accounted in btrfs_find_all_roots(). Then accessing ulist->roots with rb_first() will return NULL pointer. [FIX] For need_check() function, if @roots is empty, meaning it's a tree reloc tree, always check them. Although this can be slow, but at least it's safe that we won't skip any possible wrong tree block. Fixes: 5e2dc770471b ("btrfs-progs: check: skip shared node or leaf check for low_memory mode") Signed-off-by: Qu Wenruo <wqu@suse.com> --- cmds-check.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)