On Wed, Nov 12, 2014 at 05:49:39PM +0800, Xiaoguang Wang wrote:
> 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@xxxxxxxxxxxxxx>
> ---
> 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);
> +
Aha! expand_inode_table() fails to recompute the checksums of the inode blocks
it's moving around, and happily your change takes care of recomputing the inode
checksums for a metadata_csum FS. The changelog for this patch doesn't mention
this, but it should.
There ought to be a regression test for this. Can you send one along, please?
I crafted my own test case for the metadata_csum failure while trying to figure
out what this patchset does, so I'll simply send it out. Unfortunately, the
test requires a fix for a bug in the hugefile code that I'll cram onto the
patchbomb.
Other than that, you can add for all three patches:
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> if (l_flag)
> list_super(sb);
> if (stride_set) {
> --
> 1.8.2.1
>
> --
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