Ted, did you have any comment or objections to this patch?
Thanks,
Curt
On Mon, Jun 22, 2009 at 9:42 AM, Curt Wohlgemuth<curtw@xxxxxxxxxx> wrote:
> Hi Ted:
>
> I think the following patch is sufficient. It explicitly sets the aops to
> ext4_writeback_aops if there is no delayed allocation and no journal.
>
> I tested the locale-gen example with all combinations of
>
> data=writeback
> data=ordered
> data=journal
> <no journal at all>
>
> and
>
> delalloc
> nodelalloc
>
> and it works correctly now. The paths for writeback seem fine to me for an
> inode w/o a journal.
>
>
> Signed-off-by: Curt Wohlgemuth <curtw@xxxxxxxxxx>
> ---
> --- 2.6.26/fs/ext4/inode.c.orig 2009-06-09 20:05:27.000000000 -0700
> +++ 2.6.26/fs/ext4/inode.c 2009-06-22 08:55:13.000000000 -0700
> @@ -3442,15 +3442,12 @@ static const struct address_space_operat
>
> void ext4_set_aops(struct inode *inode)
> {
> - if (ext4_should_order_data(inode) &&
> - test_opt(inode->i_sb, DELALLOC))
> + if (test_opt(inode->i_sb, DELALLOC))
> inode->i_mapping->a_ops = &ext4_da_aops;
> else if (ext4_should_order_data(inode))
> inode->i_mapping->a_ops = &ext4_ordered_aops;
> - else if (ext4_should_writeback_data(inode) &&
> - test_opt(inode->i_sb, DELALLOC))
> - inode->i_mapping->a_ops = &ext4_da_aops;
> - else if (ext4_should_writeback_data(inode))
> + else if (ext4_should_writeback_data(inode) ||
> + EXT4_JOURNAL(inode) == NULL)
> inode->i_mapping->a_ops = &ext4_writeback_aops;
> else
> inode->i_mapping->a_ops = &ext4_journalled_aops;
>
>
> On Wed, Jun 17, 2009 at 4:46 PM, Theodore Tso<tytso@xxxxxxx> wrote:
>> Hi Curt,
>>
>> Thanks for your analysis of the bug. The reason for the strange logic
>> in ext4_set_aops() is because at the moment the code doesn't support
>> the combination of data=journalled && delalloc. That's why it was
>> explicitly checking for ext4_should_order_data() and
>> ext4_should_writeback_data().
>>
>> We have a check for this in ext4_fill_super(), so your patch should be
>> safe, since the combination of ext4_should_journal_data &&
>> test_opt(inode->i_sb, DELALLOC) should never happen.
>>
>> As to your question of whether the nodelalloc and nojournal case
>> should really be ext4_journalled_aops, I suspect ext4_writeback_aops
>> makes more sense. I haven't audited all of the code paths to make
>> sure they DTRT in the non-journalled case yet, though.
>>
>> - Ted
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>
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