linux-ext4 - [PATCH 3/4] e2fsprogs/tune2fs: rewrite metadata checksums when resizing inode size

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Date:	Tue, 11 Nov 2014 14:59:28 +0800
From:	Xiaoguang Wang <wangxg.fnst@...fujitsu.com>
To:	<linux-ext4@...r.kernel.org>
CC:	<tytso@....edu>, <darrick.wong@...cle.com>,
	Xiaoguang Wang <wangxg.fnst@...fujitsu.com>
Subject: [PATCH 3/4] e2fsprogs/tune2fs: rewrite metadata checksums when resizing inode size

When we use tune2fs -I new_ino_size to change inode size, if everything is OK,
the corresponding ext4_group_desc.bg_free_blocks_count will be decreased, so
obviously, we need to re-compute the group descriptor checksums, fix this. If
not doing this, mount operation will fail.

Meanwhile, the patch will trigger an existing memory write overflow, which will
casue segfault, please see the next patch.

Signed-off-by: Xiaoguang Wang <wangxg.fnst@...fujitsu.com>
---
 misc/tune2fs.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index 065b483..91dc7c1 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -2908,8 +2908,7 @@ retry_open:
 				EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 			rewrite_checksums = 1;
 	}
-	if (rewrite_checksums)
-		rewrite_metadata_checksums(fs);
+
 	if (I_flag) {
 		if (mount_flags & EXT2_MF_MOUNTED) {
 			fputs(_("The inode size may only be "
@@ -2935,6 +2934,7 @@ retry_open:
 		if (resize_inode(fs, new_inode_size) == 0) {
 			printf(_("Setting inode size %lu\n"),
 							new_inode_size);
+			rewrite_checksums = 1;
 		} else {
 			printf("%s", _("Failed to change inode size\n"));
 			rc = 1;
@@ -2942,6 +2942,9 @@ retry_open:
 		}
 	}
 
+	if (rewrite_checksums)
+		rewrite_metadata_checksums(fs);
+
 	if (l_flag)
 		list_super(sb);
 	if (stride_set) {
-- 
1.8.2.1

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