Re: FreeBSD is receiving traps on os/FileJournal.cc:1036

[Willem Jan Withagen <wjw@digiware.nl>]

On 16-12-2015 13:51, Xinze Chi (信泽) wrote:
> Would you mind create an issue in http://tracker.ceph.com/ and tell me
> how to reproduce the bug?

You are aware that that requires running FreeBSD?

I will enter a ticket into the tracker.

--WjW


> Thanks.
>
> 2015-12-16 18:26 GMT+08:00 Willem Jan Withagen <wjw@digiware.nl>:
>> On 16-12-2015 10:40, Xinze Chi (信泽) wrote:
>>>
>>> Because we use the new strategy for filejournal in master branch. the
>>> write entry submit to writeq is aligned already.
>>> So if assert at this line, this strategy should have bug.
>>>
>>> I do not know why you have some heads #include, Maybe you modify the
>>> logic in filejournal?
>>
>>
>> No, the adds I've done are to work around the fact that the linux_version
>> stuff
>> is not really going to work for FreeBSD. Not the test, nor the resulting
>> code.
>>
>> So the header part of the file  now looks like:
>> #include "common/blkdev.h"
>> #if defined(__linux__)
>> #include "common/linux_version.h"
>> #endif
>>
>> #if defined(__FreeBSD__)
>> #include "common/freebsd_version.h"
>> #define O_DSYNC O_SYNC
>> #endif
>>
>> The remainder of the diffs are about locking when using aio, which i do not
>> ATM.
>>
>> So never say never with software, but I think I've left the logic as it
>> is/was.
>>
>> --WjW
>>
>>
>>>
>>> 2015-12-16 17:20 GMT+08:00 Willem Jan Withagen <wjw@digiware.nl>:
>>>>
>>>> On 16-12-2015 02:57, Xinze Chi (信泽) wrote:
>>>>>
>>>>> You mean your ceph assert(0 == "bl should be align"), right?
>>>>>
>>>>> But in master branch, the 1036 line is not assert(0 == "bl should be
>>>>> align").
>>>>
>>>>
>>>> Yes you are correct. I think I have some heade #includes why this moves
>>>> down in my file.
>>>>
>>>> None the less I still get trapped on that specific assert.
>>>>
>>>> Next question is of course why this code is what it is. Since once the
>>>> assert triggers, the remainder does not get executed.
>>>> Unless compiled with NDEBUG, then only the warning gets printed.
>>>> But the other asserts never get triggered.
>>>>
>>>> So back to my original question, Why have this very stringent test and
>>>> than in test/buffer.cc forgo the fact that this could/should be aligned.
>>>>
>>>> --WjW
>>>>
>>>>
>>>>> 2015-12-16 7:56 GMT+08:00 Willem Jan Withagen <wjw@digiware.nl>:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I'm receiving traps when running the tests going with 'gmake check'
>>>>>> and on one of the tests it traps on:
>>>>>>
>>>>>> os/FileJournal.cc:1036
>>>>>> void FileJournal::align_bl(off64_t pos, bufferlist& bl)
>>>>>> {
>>>>>>     // make sure list segments are page aligned
>>>>>>     if (directio && (!bl.is_aligned(block_size) ||
>>>>>>                      !bl.is_n_align_sized(CEPH_MINIMUM_BLOCK_SIZE))) {
>>>>>>       assert(0 == "bl should be align");
>>>>>>       if ((bl.length() & (CEPH_MINIMUM_BLOCK_SIZE - 1)) != 0 ||
>>>>>>           (pos & (CEPH_MINIMUM_BLOCK_SIZE - 1)) != 0)
>>>>>>         dout(0) << "rebuild_page_aligned failed, " << bl << dendl;
>>>>>>       assert((bl.length() & (CEPH_MINIMUM_BLOCK_SIZE - 1)) == 0);
>>>>>>       assert((pos & (CEPH_MINIMUM_BLOCK_SIZE - 1)) == 0);
>>>>>>     }
>>>>>> }
>>>>>>
>>>>>> And then I get confused with the following commit in other tests:
>>>>>> commit 8ed724222651812c2ee8cc3804dc1f54c973897d
>>>>>> Author: Kefu Chai <kchai@redhat.com>
>>>>>> Date:   Fri Sep 4 01:23:31 2015 +0800
>>>>>>
>>>>>>       test/bufferlist: do not expect !is_page_aligned() after unaligned
>>>>>> rebuild
>>>>>>
>>>>>>       if the size of a bufferlist is page aligned we allocate page
>>>>>> aligned
>>>>>>       memory chunk for it when rebuild() is called. otherwise we just
>>>>>> call
>>>>>>       the plain new() to allocate new memory chunk for holding the
>>>>>> continuous
>>>>>>       buffer. but we should not expect that `new` allocator always
>>>>>> returns
>>>>>>       unaligned memory chunks. instead, it *could* return page aligned
>>>>>>       memory chunk as long as the allocator feels appropriate. so, the
>>>>>>       `EXPECT_FALSE(bl.is_page_aligned())` after the `rebuild()` call is
>>>>>>       removed.
>>>>>>
>>>>>>       Signed-off-by: Kefu Chai <kchai@redhat.com>
>>>>>>
>>>>>> Could these 2 be related, and do I have an alignment problem when
>>>>>> allocating buffers and bufferlists....
>>>>>>
>>>>>> Note that I also have not solved the illegal writes to _len in
>>>>>> bufferlists when running unittest_erasure_code_shec_arguments.
>>>>>>
>>>>>> So any suggestions as to where to look at for this, are welcome.
>>>>>>
>>>>>> --WjW
>>>>>>
>>>>>> --
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>>
>>
>
>
>
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