linux-ext4 - [PATCH v3 2/3] e2fsprogs/tune2fs: rewrite metadata checksums when resizing inode size

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Date:	Fri, 14 Nov 2014 17:15:36 +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 v3 2/3] 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, and the inode
's size has also changed, we also need to recompute the checksums of inodes for
metadata_csum filesystem, so here we choose to call a rewrite_metadata_checksums(),
this will fix checksum issues.

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>
Reviewed-by: Darrick J. Wong <darrick.wong@...cle.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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