[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <20070803180916.GT6142@schatzie.adilger.int>
Date: Fri, 3 Aug 2007 12:09:16 -0600
From: Andreas Dilger <adilger@...sterfs.com>
To: Yan Zheng <yanzheng@...n.com>
Cc: linux-ext4@...r.kernel.org
Subject: Re: How to insure ext4_alloc_blocks always returns blocks below 0xffffffff when using indirect index.
On Aug 03, 2007 10:22 +0800, Yan Zheng wrote:
> Druing reading the source codes of indirect index, there is a doubt
> in my mind. When using indirect index, physical block number must not
> exceed 0xffffffff, but I cann' t find any clue about how
> ext4_alloc_blocks insure that. Codes that check 64bit_feature is only
> in ext4_fill_super and they do nothing affects block allocation
> algorithm. Maybe ext4_alloc_blocks should check whether inode has
> EXT4_EXTENTS_FL flags and only search block groups that have blocks
> below 0xffffffff when not.
>
> The source codes I read is 2.6.22.
Good question. It is intended that extents be used for filesystems
larger than 2^32 blocks, but there is no guarantee that existing
block-mapped files will not still exist.
I think the check you propose makes sense. The code should return
EFBIG or maybe EOVERFLOW in this case (not ENOSPC I think).
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
-
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists