Re: Btrfs check reports errors, filesystem seems fine

[Filippe LeMarchand <gasinvein@gmail.com>]

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Sure, here it is:
https://drive.google.com/drive/folders/0B1ax9Am81gx9YjJBVVA0LXRHeGc

In a letter dated Tuesday, July 4, 2017 16:16:36 MSK user Lu Fengqi wrote:
> On Mon, Jul 03, 2017 at 08:34:52AM +0800, Qu Wenruo wrote:
> >
> >
> >At 07/01/2017 07:59 PM, Filippe LeMarchand wrote:
> >> Hello everyone.
> >> 
> >> I have an btrfs root partition on Intel 530 ssd, which mounts without errors and seem to work fine,
> >> but `btrfs check` gives me foloowing output (and --repair doesn't remove errors):
> >> 
> >> enabling repair mode
> >> Checking filesystem on /dev/sda2
> >> UUID: 12c84aa3-ce65-4390-807e-a72cc8a7445e
> >> checking extents
> >> Fixed 0 roots.
> >> checking free space cache
> >> cache and super generation don't match, space cache will be invalidated
> >> checking fs roots
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >
> >This means that in dir whose inode number is 79177, it has a child inode
> >pointer pointing to depercated.sxt.
> >
> >But it doesn't have dir index and corresponding inode ref, which is breaking
> >the cross reference rule of btrfs.
> >
> >Would you please run the following command to dump needed info for us to
> >debug?
> >
> ># btrfs-debug-tree /dev/sda2 | grep 79177 -C 10
> >
> >and
> >
> ># btrfs-debug-tree /dev/sda2 | grep deprecated.sxt -C 10
> >
> >and
> >
> ># btrfs-debug-tree /dev/sda2 | grep deprecated.txt -C 10
> >
> >
> >Considering the output has both .txt and .sxt, I think that's the problem.
> >But such bit-flip should be detected by tree block csum.
> >I'm not sure what's wrong with it.
> >
> >Thanks,
> >Qu
> >
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> 	unresolved ref dir 79177 index 0 namelen 14 name deprecated.sxt filetype 1 errors 6, no dir index, no inode ref
> >> 	unresolved ref dir 79177 index 417 namelen 14 name deprecated.txt filetype 1 errors 1, no dir item
> >> checking csums
> >> checking root refs
> >> found 23421812736 bytes used err is 0
> >> total csum bytes: 21531608
> >> total tree bytes: 776650752
> >> total fs tree bytes: 711278592
> >> total extent tree bytes: 36798464
> >> btree space waste bytes: 116002036
> >> file data blocks allocated: 850546470912
> >>   referenced 27611987968
> >> 
> >> Is it dangerous and what should I do about it?
> >> 
> >> I also tried --clear-space-cache, but it just removes the line about space cache.
> >> 
> >
> >
> >--
> >To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> >the body of a message to majordomo@vger.kernel.org
> >More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> I'm afraid that your mail may be rejected because the attachment size
> exceeds the allowable limit(100kB) of btrfs mailing list. Could you
> share the attachment by google drive? 
> 
> Lastly, while Qu's timing is too tight, I will assist you on this issue.
> 
> 

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