From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:4976 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752632AbaJCOio (ORCPT ); Fri, 3 Oct 2014 10:38:44 -0400 Received: from pps.filterd (m0004346 [127.0.0.1]) by mx0a-00082601.pphosted.com (8.14.5/8.14.5) with SMTP id s93EXpEX023380 for ; Fri, 3 Oct 2014 07:38:44 -0700 Received: from mail.thefacebook.com (mailwest.thefacebook.com [173.252.71.148]) by mx0a-00082601.pphosted.com with ESMTP id 1prpa2upfd-1 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=OK) for ; Fri, 03 Oct 2014 07:38:44 -0700 From: Josef Bacik To: Subject: [PATCH] Btrfs-progs: add shift_items to btrfs-corrupt-block V2 Date: Fri, 3 Oct 2014 10:38:41 -0400 Message-ID: <1412347121-2971-1-git-send-email-jbacik@fb.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-btrfs-owner@vger.kernel.org List-ID: A user had a corrupted fs where his items where shifted oddly. This adds the functionality I needed to btrfs-corrupt-block in order to reproduce this corruption in order to make fsck fix this sort of problem. Thanks, Signed-off-by: Josef Bacik --- V1->V2: fix shift issue, we need to use btrfs_leaf_data() in our math. btrfs-corrupt-block.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/btrfs-corrupt-block.c b/btrfs-corrupt-block.c index 474d48f..bb735cc 100644 --- a/btrfs-corrupt-block.c +++ b/btrfs-corrupt-block.c @@ -303,6 +303,7 @@ enum btrfs_file_extent_field { enum btrfs_metadata_block_field { BTRFS_METADATA_BLOCK_GENERATION, + BTRFS_METADATA_BLOCK_SHIFT_ITEMS, BTRFS_METADATA_BLOCK_BAD, }; @@ -332,6 +333,8 @@ convert_metadata_block_field(char *field) { if (!strncmp(field, "generation", FIELD_BUF_LEN)) return BTRFS_METADATA_BLOCK_GENERATION; + if (!strncmp(field, "shift_items", FIELD_BUF_LEN)) + return BTRFS_METADATA_BLOCK_SHIFT_ITEMS; return BTRFS_METADATA_BLOCK_BAD; } @@ -538,6 +541,27 @@ out: return ret; } +static void shift_items(struct btrfs_root *root, struct extent_buffer *eb) +{ + int nritems = btrfs_header_nritems(eb); + int shift_space = btrfs_leaf_free_space(root, eb) / 2; + int slot = nritems / 2; + int i = 0; + unsigned int data_end = btrfs_item_offset_nr(eb, nritems - 1); + + /* Shift the item data up to and including slot back by shift space */ + memmove_extent_buffer(eb, btrfs_leaf_data(eb) + data_end - shift_space, + btrfs_leaf_data(eb) + data_end, + btrfs_item_offset_nr(eb, slot - 1) - data_end); + + /* Now update the item pointers. */ + for (i = nritems - 1; i >= slot; i--) { + u32 offset = btrfs_item_offset_nr(eb, i); + offset -= shift_space; + btrfs_set_item_offset(eb, btrfs_item_nr(i), offset); + } +} + static int corrupt_metadata_block(struct btrfs_root *root, u64 block, char *field) { @@ -608,6 +632,9 @@ static int corrupt_metadata_block(struct btrfs_root *root, u64 block, bogus = generate_u64(orig); btrfs_set_header_generation(eb, bogus); break; + case BTRFS_METADATA_BLOCK_SHIFT_ITEMS: + shift_items(root, path->nodes[level]); + break; default: ret = -EINVAL; break; -- 1.8.3.1