From: Ted Ts'o <tytso@mit.edu>
To: Robin Dong <hao.bigrat@gmail.com>
Cc: linux-ext4@vger.kernel.org, Robin Dong <sanbai@taobao.com>
Subject: Re: [PATCH 1/4] ext4: use stream-alloc when mb_group_prealloc set to zero
Date: Wed, 26 Oct 2011 05:17:10 -0400 [thread overview]
Message-ID: <20111026091710.GS31921@thunk.org> (raw)
In-Reply-To: <1316070580-10723-1-git-send-email-hao.bigrat@gmail.com>
On Thu, Sep 15, 2011 at 03:09:37PM +0800, Robin Dong wrote:
> From: Robin Dong <sanbai@taobao.com>
>
> The kernel will crash on
>
> ext4_mb_mark_diskspace_used:
> BUG_ON(ac->ac_b_ex.fe_len <= 0);
>
> after we set /sys/fs/ext4/sda/mb_group_prealloc to zero and create new files in an ext4 filesystem.
>
> The reason is: ac_b_ex.fe_len also set to zero(mb_group_prealloc) in ext4_mb_normalize_group_request
> because the ac_flags contains EXT4_MB_HINT_GROUP_ALLOC.
>
> I think when someone set mb_group_prealloc to zero, it means DO NOT USE GROUP PREALLOCATION,
> so we should set alloc-strategy to STREAM in this case.
>
> Signed-off-by: Robin Dong <sanbai@taobao.com>
Thanks, applied.
- Ted
prev parent reply other threads:[~2011-10-26 9:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-15 7:09 [PATCH 1/4] ext4: use stream-alloc when mb_group_prealloc set to zero Robin Dong
2011-09-15 7:09 ` [PATCH 2/4] ext4: remove unused argument in ext4_mb_generate_from_pa Robin Dong
2011-10-26 9:24 ` Ted Ts'o
2011-09-15 7:09 ` [PATCH 3/4] ext4: remove unused argument in mb_find_extent Robin Dong
2011-10-26 9:34 ` Ted Ts'o
2011-09-15 7:09 ` [PATCH 4/4] ext4: fix a wrong comment in __mb_check_buddy Robin Dong
2011-10-26 12:53 ` Ted Ts'o
2011-10-26 9:17 ` Ted Ts'o [this message]
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