On Tue, May 10, 2011 at 10:35 PM, Lukas Czerner <lczerner@xxxxxxxxxx> wrote:
> On Tue, 10 May 2011, Yongqiang Yang wrote:
>
>> v1->v2:
>> Add more specific description.
>>
>> To get delayed-extent information, ext4_ext_fiemap_cb() lookups pagecache,
>> it thus collects information starting from a page's head block.
>> If blockszie < pagesize, the beginning blocks of a page may lie before the
>> range. ext4_ext_fiemap_cb() should proceed ignoring them, because they
>> has been handled before.
>
> Thanks for the description, but I have one question below.
>
>>
>> Reported-by: Amir Goldstein <amir73il@xxxxxxxxxxxx>
>> Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
>> ---
>> fs/ext4/extents.c | 7 ++++++-
>> 1 files changed, 6 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
>> index e363f21..ec37109 100644
>> --- a/fs/ext4/extents.c
>> +++ b/fs/ext4/extents.c
>> @@ -3718,9 +3718,14 @@ out:
>>
>> bh = head;
>> do {
>> + if (end < newex->ec_block)
>> + /* The buffer is not in
>> + * the request range.
>> + */
>> + continue;
> So if the condition is true, then we might leave the loop, because (bh ==
> head) in the first iteration, is that desired behavior? Also if we hit
> this condition in other than first iteration we will spin forever. I do
> not think this is right. How did you tested this case ?
You are right. Maybe the patch sent out is not same as the patch with
which I tested. What a stupid error!
I am not sure what happened now. I will check the patch with which I
tested tomorrow.
My working tree passed xfstests 225 in both 1k blocksize and 4k
blocksize cases.
Sorry!
Yongqiang.
>
> Thanks!
> -Lukas
>
>> if (buffer_mapped(bh)) {
>> /* get the 1st mapped buffer. */
>> - if (end > newex->ec_block +
>> + if (end >= newex->ec_block +
>> newex->ec_len)
>> /* The buffer is out of
>> * the request range.
>>
>
--
Best Wishes
Yongqiang Yang
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