Re: [Bug #14472] EXT4 corruption
From: Andrew Lutomirski
Date: Tue Nov 03 2009 - 18:43:22 EST
On Thu, Oct 29, 2009 at 5:23 PM, Theodore Tso <tytso@xxxxxxx> wrote:
> On Thu, Oct 29, 2009 at 03:57:32PM -0400, Andrew Lutomirski wrote:
>>
>> This but is *not* fixed. I just triggered it a few minutes ago by
>> abusing i915 and drm, which caused a panic. This is slightly newer
>> than 2.6.32-rc5, with a couple of i915 bugfixes thrown in.
>
> Andrew, can you test to see if this patch helps?
>
> Thanks,
>
> - Ted
>
> commit a8836b1d6f92273e001012c7705ae8f4c3d5fb65
> Author: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> Date: Tue Oct 27 15:36:38 2009 +0530
>
> ext4: discard preallocation during truncate
>
> We need to make sure when we drop and reacquire the inode's
> i_data_sem we discard the inode preallocation. Otherwise we
> could have blocks marked as free in bitmap but still belonging
> to prealloc space.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 5c5bc5d..a1ef1c3 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -209,6 +209,12 @@ static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
> up_write(&EXT4_I(inode)->i_data_sem);
> ret = ext4_journal_restart(handle, blocks_for_truncate(inode));
> down_write(&EXT4_I(inode)->i_data_sem);
> + /*
> + * We have dropped i_data_sem. So somebody else could have done
> + * block allocation. So discard the prealloc space created as a
> + * part of block allocation
> + */
> + ext4_discard_preallocations(inode);
>
> return ret;
> }
>
It looks like 2.6.32-rc6 is supposed to fix this bug, but it also
looks like this patch didn't make it in. Should I still be using this
patch?
Thanks,
Andy
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