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 12B1170838; Mon, 23 Jun 2025 21:58:52 +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=1750715932; cv=none; b=A8/6swMnMv/mJQMqHUCmUOjNyJMAtrzV4h2EO0ObyxWHvfyMmJ5vgjPilN/73sDiRu53U65p3npJZLL3KJ+Gd+ECcowsfI7U7gA18Ie79dj+FmIXxWMakujgtwmSFkMqotX3nZxr0r21llUprFexfm2J5JVsjr3eLvLe+uj5Sik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750715932; c=relaxed/simple; bh=l98DksYqtW+A/wqOzKdSQt0qAZFdmDYup0fGNjkLxY4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aVMD9FhGLSrUtwP/mUjCzMgshGCnAUPsCioj/4dp8Eha6O0iU5tv4o1ClVDnJ+8w3PS0v1aW+xnD2wKN8idd5y3ogrnebfM7SuJf8PMffWpQ9ng5Z4/0tH+jo7Vh7rS9CXaVEHZzE++qv3NjLTciUj4Bt2JJIH17WUA0kT2qm5M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fUESRquK; 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="fUESRquK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95EEAC4CEEA; Mon, 23 Jun 2025 21:58:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750715931; bh=l98DksYqtW+A/wqOzKdSQt0qAZFdmDYup0fGNjkLxY4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fUESRquKev3GEviH8Sd6MjL4kn2VsQ3SxzoSfNVpKNAtarxJqqJX7ECV+uwKFiiTs qp/LNMAZr6kIaPOQi0yOMaxJq49bcg5Pl7qKbtksvDs5XjBhxHYLvzokqdDrCe1Zta FYovPd7/4YQQoE2abV52gYCp3hs6W9PQ/7T8tboA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhang Yi , Theodore Tso , Sasha Levin Subject: [PATCH 5.15 292/411] ext4: prevent stale extent cache entries caused by concurrent get es_cache Date: Mon, 23 Jun 2025 15:07:16 +0200 Message-ID: <20250623130641.003629254@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130632.993849527@linuxfoundation.org> References: <20250623130632.993849527@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Yi [ Upstream commit f22a0ef2231a7d8374bb021eb86404d0e9de5a02 ] The EXT4_IOC_GET_ES_CACHE and EXT4_IOC_PRECACHE_EXTENTS currently invokes ext4_ext_precache() to preload the extent cache without holding the inode's i_rwsem. This can result in stale extent cache entries when competing with operations such as ext4_collapse_range() which calls ext4_ext_remove_space() or ext4_ext_shift_extents(). The problem arises when ext4_ext_remove_space() temporarily releases i_data_sem due to insufficient journal credits. During this interval, a concurrent EXT4_IOC_GET_ES_CACHE or EXT4_IOC_PRECACHE_EXTENTS may cache extent entries that are about to be deleted. As a result, these cached entries become stale and inconsistent with the actual extents. Loading the extents cache without holding the inode's i_rwsem or the mapping's invalidate_lock is not permitted besides during the writeback. Fix this by holding the i_rwsem during EXT4_IOC_GET_ES_CACHE and EXT4_IOC_PRECACHE_EXTENTS. Signed-off-by: Zhang Yi Link: https://patch.msgid.link/20250423085257.122685-6-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/extents.c | 2 ++ fs/ext4/ioctl.c | 8 +++++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index e41a6d642472b..35bc58a26f7f4 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -5041,7 +5041,9 @@ int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo, } if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) { + inode_lock_shared(inode); error = ext4_ext_precache(inode); + inode_unlock_shared(inode); if (error) return error; fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE; diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 18002b0a908ce..bd90b454c6213 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1130,8 +1130,14 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return 0; } case EXT4_IOC_PRECACHE_EXTENTS: - return ext4_ext_precache(inode); + { + int ret; + inode_lock_shared(inode); + ret = ext4_ext_precache(inode); + inode_unlock_shared(inode); + return ret; + } case FS_IOC_SET_ENCRYPTION_POLICY: if (!ext4_has_feature_encrypt(sb)) return -EOPNOTSUPP; -- 2.39.5