From f469c8bd90b7d595414e4b1876983dc94d0df47e Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 12 Apr 2023 11:33:10 +0100 Subject: btrfs: unexport btrfs_prev_leaf() btrfs_prev_leaf() is not used outside ctree.c, so there's no need to export it at ctree.h - just make it static at ctree.c and move its definition above btrfs_search_slot_for_read(), since that function calls it. Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.c | 161 ++++++++++++++++++++++++++++--------------------------- 1 file changed, 81 insertions(+), 80 deletions(-) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 2ff2961b1183..28b0402a008f 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2378,6 +2378,87 @@ done: return ret; } +/* + * Search the tree again to find a leaf with smaller keys. + * Returns 0 if it found something. + * Returns 1 if there are no smaller keys. + * Returns < 0 on error. + * + * This may release the path, and so you may lose any locks held at the + * time you call it. + */ +static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) +{ + struct btrfs_key key; + struct btrfs_key orig_key; + struct btrfs_disk_key found_key; + int ret; + + btrfs_item_key_to_cpu(path->nodes[0], &key, 0); + orig_key = key; + + if (key.offset > 0) { + key.offset--; + } else if (key.type > 0) { + key.type--; + key.offset = (u64)-1; + } else if (key.objectid > 0) { + key.objectid--; + key.type = (u8)-1; + key.offset = (u64)-1; + } else { + return 1; + } + + btrfs_release_path(path); + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret <= 0) + return ret; + + /* + * Previous key not found. Even if we were at slot 0 of the leaf we had + * before releasing the path and calling btrfs_search_slot(), we now may + * be in a slot pointing to the same original key - this can happen if + * after we released the path, one of more items were moved from a + * sibling leaf into the front of the leaf we had due to an insertion + * (see push_leaf_right()). + * If we hit this case and our slot is > 0 and just decrement the slot + * so that the caller does not process the same key again, which may or + * may not break the caller, depending on its logic. + */ + if (path->slots[0] < btrfs_header_nritems(path->nodes[0])) { + btrfs_item_key(path->nodes[0], &found_key, path->slots[0]); + ret = comp_keys(&found_key, &orig_key); + if (ret == 0) { + if (path->slots[0] > 0) { + path->slots[0]--; + return 0; + } + /* + * At slot 0, same key as before, it means orig_key is + * the lowest, leftmost, key in the tree. We're done. + */ + return 1; + } + } + + btrfs_item_key(path->nodes[0], &found_key, 0); + ret = comp_keys(&found_key, &key); + /* + * We might have had an item with the previous key in the tree right + * before we released our path. And after we released our path, that + * item might have been pushed to the first slot (0) of the leaf we + * were holding due to a tree balance. Alternatively, an item with the + * previous key can exist as the only element of a leaf (big fat item). + * Therefore account for these 2 cases, so that our callers (like + * btrfs_previous_item) don't miss an existing item with a key matching + * the previous key we computed above. + */ + if (ret <= 0) + return 0; + return 1; +} + /* * helper to use instead of search slot if no exact match is needed but * instead the next or previous item should be returned. @@ -4473,86 +4554,6 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, return ret; } -/* - * search the tree again to find a leaf with lesser keys - * returns 0 if it found something or 1 if there are no lesser leaves. - * returns < 0 on io errors. - * - * This may release the path, and so you may lose any locks held at the - * time you call it. - */ -int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) -{ - struct btrfs_key key; - struct btrfs_key orig_key; - struct btrfs_disk_key found_key; - int ret; - - btrfs_item_key_to_cpu(path->nodes[0], &key, 0); - orig_key = key; - - if (key.offset > 0) { - key.offset--; - } else if (key.type > 0) { - key.type--; - key.offset = (u64)-1; - } else if (key.objectid > 0) { - key.objectid--; - key.type = (u8)-1; - key.offset = (u64)-1; - } else { - return 1; - } - - btrfs_release_path(path); - ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); - if (ret <= 0) - return ret; - - /* - * Previous key not found. Even if we were at slot 0 of the leaf we had - * before releasing the path and calling btrfs_search_slot(), we now may - * be in a slot pointing to the same original key - this can happen if - * after we released the path, one of more items were moved from a - * sibling leaf into the front of the leaf we had due to an insertion - * (see push_leaf_right()). - * If we hit this case and our slot is > 0 and just decrement the slot - * so that the caller does not process the same key again, which may or - * may not break the caller, depending on its logic. - */ - if (path->slots[0] < btrfs_header_nritems(path->nodes[0])) { - btrfs_item_key(path->nodes[0], &found_key, path->slots[0]); - ret = comp_keys(&found_key, &orig_key); - if (ret == 0) { - if (path->slots[0] > 0) { - path->slots[0]--; - return 0; - } - /* - * At slot 0, same key as before, it means orig_key is - * the lowest, leftmost, key in the tree. We're done. - */ - return 1; - } - } - - btrfs_item_key(path->nodes[0], &found_key, 0); - ret = comp_keys(&found_key, &key); - /* - * We might have had an item with the previous key in the tree right - * before we released our path. And after we released our path, that - * item might have been pushed to the first slot (0) of the leaf we - * were holding due to a tree balance. Alternatively, an item with the - * previous key can exist as the only element of a leaf (big fat item). - * Therefore account for these 2 cases, so that our callers (like - * btrfs_previous_item) don't miss an existing item with a key matching - * the previous key we computed above. - */ - if (ret <= 0) - return 0; - return 1; -} - /* * A helper function to walk down the tree starting at min_key, and looking * for nodes or leaves that are have a minimum transaction id. -- cgit v1.2.3