From 6aebc0d11a10f48a54146c5e71bbef15a1a458fc Mon Sep 17 00:00:00 2001 From: Tom Rini Date: Sat, 27 Apr 2019 11:34:55 -0400 Subject: [PATCH] Revert "fs: btrfs: fix false negatives in ROOT_ITEM search" Per Pierre this change shouldn't have been applied as it was superseded by "fs: btrfs: fix btrfs_search_tree invalid results" which is also applied now as 1627e5e5985d. This reverts commit 633967f9818cb6a0e87ffa8cba33148a5bcc6edb. Signed-off-by: Tom Rini --- fs/btrfs/ctree.h | 44 ++++++-------------------------------------- 1 file changed, 6 insertions(+), 38 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index ca44a2404d..65c152a52f 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -292,52 +292,20 @@ btrfs_search_tree_key_type(const struct btrfs_root *root, u64 objectid, { struct btrfs_key key, *res; - /* - * In some cases (e.g. tree roots), we need to look for a given - * objectid and type without knowing the offset value (3rd element of a - * btrfs tree node key). We can rely on the fact that btrfs_search_tree - * returns the first element with key >= search_key, and then perform - * our own comparison between the returned element and the search key. - * - * It is tempting to use a search key with offset 0 to perform this - * "fuzzy search". This would return the first item with the (objectid, - * type) we're looking for. However, using offset 0 has the wrong - * behavior when the wanted item is the first in a leaf: since our - * search key will be lower than the wanted item, the recursive search - * will explore the wrong branch of the tree. - * - * Instead, use the largest possible offset (-1). The result of this - * search will either be: - * 1. An element with the (objectid, type) we're looking for, if it - * has offset -1 or if it is the last element in its leaf. - * 2. The first element *after* an element with the (objectid, type) - */ key.objectid = objectid; key.type = type; - key.offset = -1; + key.offset = 0; if (btrfs_search_tree(root, &key, path)) return NULL; - /* - * Compare with the previous element first -- this is the likely case - * since the result of the search is only what we want if it had offset - * == -1 or if it was last in its leaf. - */ - if (path->slots[0] > 0) { - path->slots[0]--; - res = btrfs_path_leaf_key(path); - if (!btrfs_comp_keys_type(&key, res)) - return res; - path->slots[0]++; - } - res = btrfs_path_leaf_key(path); - if (!btrfs_comp_keys_type(&key, res)) - return res; + if (btrfs_comp_keys_type(&key, res)) { + btrfs_free_path(path); + return NULL; + } - btrfs_free_path(path); - return NULL; + return res; } static inline u32 btrfs_path_item_size(struct btrfs_path *p) -- 2.39.5