Re: nilfs_clean_segments: segment construction failed. (err=-2)

[dE <de.techno-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 06/26/14 19:04, Vyacheslav Dubeyko wrote:
> On Thu, 2014-06-26 at 11:30 +0530, dE wrote:
>
> [snip]
>> I'm using 3.14.4. I thought there was only 1 selection policy, so it's
>> set to timestamp.
> It was added 2 additional GC policies. But code for these policies is
> available in 3.15 kernel version, as I see.
>
>> nilfs-tune -l /dev/bitcoin/bitcoin
>> nilfs-tune 2.1.6
>> Filesystem volume name:   test
>> Filesystem UUID:          9e1064e0-4ce8-4831-93c0-758b46118884
>> Filesystem magic number:  0x3434
>> Filesystem revision #:    2.0
>> Filesystem features:      (none)
>> Filesystem state:         invalid or mounted
>> Filesystem OS type:       Linux
>> Block size:               1024
> Such block size can be a environment of the issue reproducing. I've
> fixed one issue for 1KB block size, namely. What do you have for 4 KB
> block size? Can you reproduce the issue for 4 KB block size?
>
>> Filesystem created:       Sun Jun 22 15:31:18 2014
> So, it's freshly created file system. Am I correct? I hoped to see the
> superblock state for the file system with issue. Or, maybe, you've found
> the issue soon after file system creation?
>
>> Last mount time:          Thu Jun 26 11:26:50 2014
>> Last write time:          Thu Jun 26 11:27:23 2014
>> Mount count:              5
>> Maximum mount count:      50
>> Reserve blocks uid:       0 (user root)
>> Reserve blocks gid:       0 (group root)
>> First inode:              11
>> Inode size:               128
>> DAT entry size:           32
>> Checkpoint size:          192
>> Segment usage size:       16
>> Number of segments:       11375
>> Device size:              23857201152
>> First data block:         4
>> # of blocks per segment:  2048
>> Reserved segments %:      1
>> Last checkpoint #:        208680
>> Last block address:       13015040
>> Last sequence #:          525413
>> Free blocks count:        3723264
>> Commit interval:          0
>> # of blks to create seg:  0
>> CRC seed:                 0x1b525ab2
>> CRC check sum:            0xcede51d1
>> CRC check data size:      0x00000118
>>
>> I suspect this has to do with the segment size. So I've re-formatted a
>> device with the default segment size. Let's see if I can reproduce it now.
> So, anyway, I need to understand how to reproduce the issue. As far as I
> can see, you have the issue on segctor side during segment construction.
> Frankly speaking, it's really bad situation. It means that you don't
> save your information into segments. Moreover, it takes place during GC
> operations. Operation of trying to create segment is repeated till
> success. So, maybe, finally you have success. Otherwise, if you have
> sequence of likewise messages ("nilfs_clean_segments: segment
> construction failed") and you need to force shutdown then, potentially,
> it means that you have dangerous situation.
>
> But, it needs to understand your issue more deeply for any final
> statements.
>
> With the best regards,
> Vyacheslav Dubeyko.
>
>

I can confirm this bug triggers cause of smaller block size. Increasing 
segment size did not help.
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