Re: Regression in suspend to ram in 2.6.31-rc kernels

[OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>]

Zdenek Kabelac <zdenek.kabelac@gmail.com> writes:

> 2009/9/5 OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>:
>> Zdenek Kabelac <zdenek.kabelac@gmail.com> writes:
>>
>>> 2009/9/4 OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>:
>>>> Christoph Hellwig <hch@lst.de> writes:
>>>>
>>>>> Note that when you rever this patch on a current kernel you do actually
>>>>> get different behvaviour than when going back to before this commit.
>>>>>
>>>>> In 2.6.30 we called ->write_super in the various sync functions and
>>>>> then ->sync_fs, in 2.6.31-rc8 you would not call any syncing at all
>>>>> anymore.  I think this patch might just be a symptom for a situation
>>>>> where the suspend code causes a sync and the mmc driver can't handle
>>>>> it anymore.
>>>
>>> So - here is the console trace from suspend when I've added
>>> dump_stack() to the fat_sync_fs()   (and also added debug prints
>>> around each call in this function -so its obvious the function is
>>> actually left - but then it freezes later somewhere.)
>>>
>>> It's interesting that 3 calls to sync happens.
>>
>> It seems
>>
>>    1) sync() (probabry "sync" command)
>>    2) sync as part of suspend sequence
>>    3) sync_filesystem() by mmc remove event
>>
>> I guess the root-cause of the problem would be 3). However, it would not
>> be easy to fix, at least, we would need to think about what we want to
>> do for it. So, to workaround it for now, I've made this patch.
>>
>> Can you try whether this patch fixes this problem?
>>
>
> So I've tested your patch - it seems to fix the problem in suspend -
> the machine sleeps - however after resume the mmc SD card becomes
> unusable to the system and appended call trace filled my message log
> very quickly:
>
> After reboot the filesystem appeared to be usable again without errors.

Thanks for testing.  "logical block size: 27499" is wrong value
completely. Of course, fatfs is assuming the blocksize is not changed.
(mmc wasn't resumed correctly?)

Well, this problem seems to be completely different problem, and it
seems the problem of suspend or mmc (or block?) stuff, or something.

It would need to be analyzed by those people.

Meanwhile, I'll apply this patch to workaround suspend problem and to
remove unneeded write for next window.

Thanks.

> Call Trace:
>  [<ffffffff81134f6b>] __getblk+0x2cb/0x300
>  [<ffffffff813dcb58>] ? _spin_unlock_irqrestore+0x38/0x80
>  [<ffffffff81135122>] __breadahead+0x12/0x40
>  [<ffffffffa0520cb7>] fat_count_free_clusters+0x307/0x320 [fat]
>  [<ffffffff81103a58>] ? check_object+0xd8/0x260
>  [<ffffffff8107d83d>] ? trace_hardirqs_on+0xd/0x10
>  [<ffffffffa0522d55>] fat_statfs+0xf5/0x110 [fat]
>  [<ffffffff8110be5c>] vfs_statfs+0x7c/0xa0
>  [<ffffffff8110c0b0>] vfs_statfs_native+0x20/0xb0
>  [<ffffffff8110c243>] sys_statfs+0x73/0xb0
>  [<ffffffff8122ab2b>] ? __up_write+0xcb/0x120
>  [<ffffffff8100c18c>] ? sysret_check+0x27/0x62
>  [<ffffffff8109eb8b>] ? audit_syscall_entry+0x28b/0x2b0
>  [<ffffffff8107d7ed>] ? trace_hardirqs_on_caller+0x15d/0x1a0
>  [<ffffffff813dbf1e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
>  [<ffffffff8100c15b>] system_call_fastpath+0x16/0x1b
> getblk(): invalid block size 512 requested
> logical block size: 27499
>
>  [<ffffffff81135122>] __breadahead+0x12/0x40
>  [<ffffffffa0520cb7>] fat_count_free_clusters+0x307/0x320 [fat]
>  [<ffffffff81103a58>] ? check_object+0xd8/0x260
>  [<ffffffff8107d83d>] ? trace_hardirqs_on+0xd/0x10
>  [<ffffffffa0522d55>] fat_statfs+0xf5/0x110 [fat]
>  [<ffffffff8110be5c>] vfs_statfs+0x7c/0xa0
>  [<ffffffff8110c0b0>] vfs_statfs_native+0x20/0xb0
>  [<ffffffff8110c243>] sys_statfs+0x73/0xb0
>  [<ffffffff8122ab2b>] ? __up_write+0xcb/0x120
>  [<ffffffff8100c18c>] ? sysret_check+0x27/0x62
>  [<ffffffff8109eb8b>] ? audit_syscall_entry+0x28b/0x2b0
>  [<ffffffff8107d7ed>] ? trace_hardirqs_on_caller+0x15d/0x1a0
>  [<ffffffff813dbf1e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
>  [<ffffffff8100c15b>] system_call_fastpath+0x16/0x1b
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>