From: Nick Dokos Subject: [PATCH][64-BIT]ext2fs_extent_get() truncates block to 32 bits. Date: Mon, 06 Apr 2009 01:37:43 -0400 Message-ID: <2299.1238996263@gamaville.dokosmarshall.org> Reply-To: nicholas.dokos@hp.com Cc: nicholas.dokos@hp.com To: linux-ext4@vger.kernel.org Return-path: Received: from qmta07.emeryville.ca.mail.comcast.net ([76.96.30.64]:45543 "EHLO QMTA07.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750900AbZDFFhs (ORCPT ); Mon, 6 Apr 2009 01:37:48 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: e2image (after enabling 64-bitness) was reporting a corrupt extent header in a 16TiB file created on a 32TiB filesystem. Checking the on-disk extents did not uncover any problem. Debugging e2image showed truncation in the ext2fs_extent_get() routine. Code examination showed an inconsistency on line 428: blk = ext2fs_le32_to_cpu(ix->ei_leaf) + ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32); blk is treated as a 64 bit quantity but it is declared blk_t. This changes it to blk64_t. With this change, e2image has been running (in raw mode) for a couple of days without error (but it has not finished producing an image yet !-). Also, although I have not checked exhaustively, debugfs seems to produce the correct set of extents for the big file (stat <13>) - without this patch, the physical block number wrapped at the 32-bit limit. The second change is not based on debugging, just code examination: ext2fs_alloc_block2() has been modified in the 64-bit patch series (in the patch called add_64-bit_alloc_interface) so that its second argument (the goal block) is a blk64_t. However, extent_node_split() calls it with its second argument explicitly cast to blk_t. That looks wrong. There are some more blk_t's used in this file (extent.c), but they are in #ifdef DEBUG code, so I have not examined them any closer and I have not changed them (yet?). Signed-off-by: Nick Dokos --- lib/ext2fs/extent.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c index a6edd0c..1778955 100644 --- a/lib/ext2fs/extent.c +++ b/lib/ext2fs/extent.c @@ -273,7 +273,7 @@ errcode_t ext2fs_extent_get(ext2_extent_handle_t handle, struct ext3_extent_idx *ix = 0; struct ext3_extent *ex; errcode_t retval; - blk_t blk; + blk64_t blk; blk64_t end_blk; int orig_op, op; @@ -904,7 +904,7 @@ static errcode_t extent_node_split(ext2_extent_handle_t handle) goal_blk = (group * handle->fs->super->s_blocks_per_group) + handle->fs->super->s_first_data_block; } - retval = ext2fs_alloc_block2(handle->fs, (blk_t) goal_blk, block_buf, + retval = ext2fs_alloc_block2(handle->fs, goal_blk, block_buf, &new_node_pblk); if (retval) goto done; -- 1.6.0.3