From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF7F422425B; Tue, 12 Aug 2025 19:03:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755025395; cv=none; b=EfotCQV4oggdLk/14nIXU9PrItxNVAbcw2w2QFlWoTQ2Az2t5ZThziNbpLeDbLtL30TQ7F9/kTQPy1n3eRwNzGAMmiLMsYNUYVb2HEhb5nHOlTA1NMtHvuleclriaKogViOh1ceT1Ecf3c11oM4dBcoJXnnYnNVbr6FFobZEqIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755025395; c=relaxed/simple; bh=MxMXoDI5BztNXVx6/F5kWzcdUXVFvQxOMBwR6hw9RDU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WIw2eXhCJNf2SL7Kq8mhmcw9CeRhTwSs1AobyxWVK8dN3v7qdcyMpATCo4/yow5pQophrjE7Cdew/W506ejr2MJoX7n9QHbQlkzR60XtantCsg1vKveJPyDMCL5R0v4fsiqRFPegIQNDcDEYnjE+JNpbzJtYv/jVVsJiVBH9jgk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zum2cRmX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zum2cRmX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F41BC4CEF0; Tue, 12 Aug 2025 19:03:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755025394; bh=MxMXoDI5BztNXVx6/F5kWzcdUXVFvQxOMBwR6hw9RDU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zum2cRmXc/z1rskP4uynX0nU8mem5JBu+gFb3RcaOD+grzpHGRtLcBT7YzUsYhZCF sxO5qsgpWfn1BqBQhCn+GU0/xQtUxCzn+HPTXaF4LM/RwJny9VctfJfWdXJyEauCde JYmfa2UVJatLlPhpHENGHACbjHPz5kMHdfJj+8S0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qu Wenruo , Filipe Manana , Sun YangKai , David Sterba , Sasha Levin Subject: [PATCH 6.15 028/480] btrfs: remove partial support for lowest level from btrfs_search_forward() Date: Tue, 12 Aug 2025 19:43:56 +0200 Message-ID: <20250812174358.498097700@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250812174357.281828096@linuxfoundation.org> References: <20250812174357.281828096@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sun YangKai [ Upstream commit 27260dd1904bb409cf84709928ba9bc5506fbe8e ] Commit 323ac95bce44 ("Btrfs: don't read leaf blocks containing only checksums during truncate") changed the condition from `level == 0` to `level == path->lowest_level`, while its original purpose was just to do some leaf node handling (calling btrfs_item_key_to_cpu()) and skip some code that doesn't fit leaf nodes. After changing the condition, the code path: 1. Also handles the non-leaf nodes when path->lowest_level is nonzero, which is wrong. However btrfs_search_forward() is never called with a nonzero path->lowest_level, which makes this bug not found before. 2. Makes the later if block with the same condition, which was originally used to handle non-leaf node (calling btrfs_node_key_to_cpu()) when lowest_level is not zero, dead code. Since btrfs_search_forward() is never called for a path with a lowest_level different from zero, just completely remove the partial support for a non-zero lowest_level, simplifying a bit the code, and assert that lowest_level is zero at the start of the function. Suggested-by: Qu Wenruo Fixes: 323ac95bce44 ("Btrfs: don't read leaf blocks containing only checksums during truncate") Reviewed-by: Filipe Manana Signed-off-by: Sun YangKai Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/ctree.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index a2e7979372cc..648531fe0900 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -4585,16 +4585,13 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, /* * 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. + * for leaves that have a minimum transaction id. * This is used by the btree defrag code, and tree logging * * This does not cow, but it does stuff the starting key it finds back * into min_key, so you can call btrfs_search_slot with cow=1 on the * key and get a writable path. * - * This honors path->lowest_level to prevent descent past a given level - * of the tree. - * * min_trans indicates the oldest transaction that you are interested * in walking through. Any nodes or leaves older than min_trans are * skipped over (without reading them). @@ -4615,6 +4612,7 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, int keep_locks = path->keep_locks; ASSERT(!path->nowait); + ASSERT(path->lowest_level == 0); path->keep_locks = 1; again: cur = btrfs_read_lock_root_node(root); @@ -4636,8 +4634,8 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, goto out; } - /* at the lowest level, we're done, setup the path and exit */ - if (level == path->lowest_level) { + /* At level 0 we're done, setup the path and exit. */ + if (level == 0) { if (slot >= nritems) goto find_next_key; ret = 0; @@ -4678,12 +4676,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, goto out; } } - if (level == path->lowest_level) { - ret = 0; - /* Save our key for returning back. */ - btrfs_node_key_to_cpu(cur, min_key, slot); - goto out; - } cur = btrfs_read_node_slot(cur, slot); if (IS_ERR(cur)) { ret = PTR_ERR(cur); @@ -4699,7 +4691,7 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, out: path->keep_locks = keep_locks; if (ret == 0) - btrfs_unlock_up_safe(path, path->lowest_level + 1); + btrfs_unlock_up_safe(path, 1); return ret; } -- 2.39.5