From mboxrd@z Thu Jan  1 00:00:00 1970
From: Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH] ext4: Only call update_backups if necessary in online
 resize.
Date: Tue, 25 Sep 2012 23:39:35 -0400
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Cc: linux-ext4@vger.kernel.org
To: Tao Ma <tm@tao.ma>
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On Mon, Sep 24, 2012 at 11:00:17PM +0800, Tao Ma wrote:
> @@ -1355,8 +1356,16 @@ exit_journal:
>  			int gdb_num;
>  			gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb);
>  			gdb_bh = sbi->s_group_desc[gdb_num];
> -			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
> -				       gdb_bh->b_size);
> +			/*
> +			 * only backup the group descriptor block
> +			 * which hasn't been updated before.
> +			 */
> +			if (old_gdb != gdb_bh->b_blocknr) {
> +				update_backups(sb, gdb_bh->b_blocknr,
> +					       gdb_bh->b_data,
> +					       gdb_bh->b_size);
> +				old_gdb = gdb_bh->b_blocknr;
> +			}
>  		}
>  	}

Don't we also need to add a call to update_backups() at the end of the
loop so we update the backup block descriptors for the very last set
of block groups?

Thanks,

						- Ted