From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-op-o15.zoho.com (sender4-op-o15.zoho.com [136.143.188.15]) (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 08B82347523; Tue, 17 Mar 2026 08:49:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.15 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773737374; cv=pass; b=cNRogjq3ifPWTaIwMckDH5b+S1yBfQYlhR8oFSkDhPyJiYLEi8IIsPeRQZ0a6osBRATB1XUf4zPQ6CxFm9noRuuXbB4G7gu1kLZOw0v1rZYx8vawslgmGNthACY/nswe301KoGodiKaBjiADVEYycnalLPS3eg53xFf5zmY+VJ8= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773737374; c=relaxed/simple; bh=2T1XEP+0MbcGvf5V4jkWy/jAlUceMp6GSTuQIhUYAm8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IxxXHAxcdZTO55Vf+AySKQgEIv3ccU1h3b5GeWtzHgfccnPRu0rXE6h6BXiLKUDPuS/g5gtJHUUUIyiMcHNv3ckl4bXRtNlTT+Gvq1/SClz1bEhszqo9isszkahvl9XwIg/LXBz9pk4cvxDtv/2dyKvmsBDmcmS2s+f1MgfwdY4= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.beauty; spf=pass smtp.mailfrom=linux.beauty; dkim=pass (1024-bit key) header.d=linux.beauty header.i=me@linux.beauty header.b=h3slt7MN; arc=pass smtp.client-ip=136.143.188.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.beauty Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.beauty Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.beauty header.i=me@linux.beauty header.b="h3slt7MN" ARC-Seal: i=1; a=rsa-sha256; t=1773737207; cv=none; d=zohomail.com; s=zohoarc; b=fryVqFhxzvVeMHpI/nWxveNM4UdB+jJhipE1ePCuTQyHACojZ0DS3oErYr2pOk3hWwzMHlHDlpkSLYcMoLyh+TJHE/rqewN63q61yV7QT/G4iz1qX0X387anNI/fMlLVTpzlE4R88VOqn+DytRKi+A0YvAjoI+lOv5gy9G5mUFI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1773737207; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=rDK5gClFMcbUS8LdYCJMAjdOkGkFNx9hD8v2sQ0+bsw=; b=MzEBrYqHbnMXc7c9pM320X2sF3OtJ2FENNxzowq//tVclDjVWwtwmB321Gcq6PxL1QrNiO222vtwwIQ/HsHkC6UNo4E7OXHg0poorJ2q9YmTGLHu1XgF8h69GoiC9e0jGOXL5pZFa+tmYDFxD42HxxWgvA+0Tpxa2wbfPVzarIo= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=linux.beauty; spf=pass smtp.mailfrom=me@linux.beauty; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1773737207; s=zmail; d=linux.beauty; i=me@linux.beauty; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=rDK5gClFMcbUS8LdYCJMAjdOkGkFNx9hD8v2sQ0+bsw=; b=h3slt7MNz0BCbeMG3aQcwjhRcN25E2QM/XlfDGlzfDn3M/MDBhvPq6KRNlEV1nSL d6nYzBtpdZ2INluGW654jdtEAEdEm22lwoclgMY82ai2cmEQ7/t3Eck2t/sYTXrtrIZ +1FHhZW5HPKlR962DvXfTEu6unOhOAh+JIXDhnC4= Received: by mx.zohomail.com with SMTPS id 17737372049957.253615372300146; Tue, 17 Mar 2026 01:46:44 -0700 (PDT) From: Li Chen To: Zhang Yi , Theodore Ts'o , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org, Li Chen Subject: [RFC v5 2/7] ext4: lockdep: handle i_data_sem subclassing for special inodes Date: Tue, 17 Mar 2026 16:46:17 +0800 Message-ID: <20260317084624.457185-3-me@linux.beauty> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260317084624.457185-1-me@linux.beauty> References: <20260317084624.457185-1-me@linux.beauty> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-ZohoMailClient: External Fast commit can hold s_fc_lock while writing journal blocks. Mapping the journal inode can take its i_data_sem. Normal inode update paths can take a data inode i_data_sem and then s_fc_lock, which makes lockdep report a circular dependency. lockdep treats all i_data_sem instances as one lock class and cannot distinguish the journal inode i_data_sem from a regular inode i_data_sem. The journal inode is not tracked by fast commit and no FC waiters ever depend on it, so this is not a real ABBA deadlock. Assign the journal inode a dedicated i_data_sem lockdep subclass to avoid the false positive. Inode cache objects can be recycled, so also reset i_data_sem to I_DATA_SEM_NORMAL when allocating an ext4 inode. Otherwise a new inode may inherit an old subclass (journal/quota/ea) and trigger lockdep warnings. Signed-off-by: Li Chen --- fs/ext4/ext4.h | 4 +++- fs/ext4/super.c | 8 ++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index bd30c24d4f948..2e1681057196a 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1025,12 +1025,14 @@ do { \ * than the first * I_DATA_SEM_QUOTA - Used for quota inodes only * I_DATA_SEM_EA - Used for ea_inodes only + * I_DATA_SEM_JOURNAL - Used for journal inode only */ enum { I_DATA_SEM_NORMAL = 0, I_DATA_SEM_OTHER, I_DATA_SEM_QUOTA, - I_DATA_SEM_EA + I_DATA_SEM_EA, + I_DATA_SEM_JOURNAL }; struct ext4_fc_inode_snap; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 79762c3e0dff3..4f5f0c21d436f 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1423,6 +1423,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb) INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work); ext4_fc_init_inode(&ei->vfs_inode); spin_lock_init(&ei->i_fc_lock); +#ifdef CONFIG_LOCKDEP + lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_NORMAL); +#endif return &ei->vfs_inode; } @@ -5863,6 +5866,11 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb, return ERR_PTR(-EFSCORRUPTED); } +#ifdef CONFIG_LOCKDEP + lockdep_set_subclass(&EXT4_I(journal_inode)->i_data_sem, + I_DATA_SEM_JOURNAL); +#endif + ext4_debug("Journal inode found at %p: %lld bytes\n", journal_inode, journal_inode->i_size); return journal_inode; -- 2.53.0