On 2011-08-10, at 9:28 PM, Yongqiang Yang wrote:
> This patch adds a function named ext4_add_new_desc() which adds
> a new desc to a fs and whose code is copied from ext4_group_add().
>
> The function will be used by new resize implementation.
Similarly, this is duplicating a hunk of code from the middle of
ext4_group_add(), and instead of just adding a second copy of that
code, ext4_group_add() should be changed to call this new function
to avoid the code duplication.
> Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
> ---
> fs/ext4/resize.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 42 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
> index 6ffbdb6..4fcd515 100644
> --- a/fs/ext4/resize.c
> +++ b/fs/ext4/resize.c
> @@ -735,6 +735,48 @@ exit_err:
> }
> }
>
> +/*
> + * ext4_add_new_desc() adds group descriptor of group @group
> + *
> + * @handle: journal handle
> + * @sb; super block
> + * @group: the group no. of the first group desc to be added
> + * @resize_inode: the resize inode
> + */
> +static int ext4_add_new_desc(handle_t *handle, struct super_block *sb,
> + ext4_group_t group, struct inode *resize_inode)
> +{
> + struct ext4_sb_info *sbi = EXT4_SB(sb);
> + struct ext4_super_block *es = sbi->s_es;
> + struct buffer_head *gdb_bh;
> + int gdb_off, gdb_num, err = 0;
> + int reserved_gdb = ext4_bg_has_super(sb, group) ?
> + le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
> +
> + gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
> + gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
> +
> + /*
> + * We will only either add reserved group blocks to a backup group
> + * or remove reserved blocks for the first group in a new group block.
> + * Doing both would be mean more complex code, and sane people don't
> + * use non-sparse filesystems anymore. This is already checked above.
> + */
> + if (gdb_off) {
> + gdb_bh = sbi->s_group_desc[gdb_num];
> + err = ext4_journal_get_write_access(handle, gdb_bh);
> + if (err)
> + goto out;
> +
> + if (reserved_gdb && ext4_bg_num_gdb(sb, group))
> + err = reserve_backup_gdb(handle, resize_inode, group);
> + } else
> + err = add_new_gdb(handle, resize_inode, group);
> +
> +out:
> + return err;
> +}
> +
> /* Add group descriptor data to an existing or new group descriptor block.
> * Ensure we handle all possible error conditions _before_ we start modifying
> * the filesystem, because we cannot abort the transaction and not have it
> --
> 1.7.5.1
>
Cheers, Andreas
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