Re: How to fix errors that check --mode lomem finds, but --mode normal doesn't?

[Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>]

At 06/21/2017 11:13 PM, Marc MERLIN wrote:
> On Tue, Jun 20, 2017 at 08:43:52PM -0700, Marc MERLIN wrote:
> > On Tue, Jun 20, 2017 at 09:31:42PM -0600, Chris Murphy wrote:
> > > On Tue, Jun 20, 2017 at 5:12 PM, Marc MERLIN <marc@xxxxxxxxxxx> wrote:
> > >
> > > > I'm now going to remount this with nospace_cache to see if your guess about
> > > > space_cache was correct.
> > > > Other suggestions also welcome :)
> > >
> > > What results do you get with lowmem mode? It won't repair without
> > > additional patches, but might give a dev a clue what's going on. I
> > > regularly see normal mode check finds no problems, and lowmem mode
> > > finds problems. Lowmem mode is a total rewrite so it's a different
> > > implementation and can find things normal mode won't.
> >
> > Oh, I kind of forgot that lowmem mode looked for more things than regular
> > mode.
> > I will run this tonight and see what it says.
>   
> It's probably still a ways from being finished given how slow lowmem is in
> comparison, but sadly it found a bunch of problems which regular mode didn't
> find.
>
> I'm pretty bummed. I just spent way too long recreating this filesystem and
> the multiple btrfs send/receive relationships from other machines. Too a bit
> over a week :(
>
> It looks like the errors are not major (especially if the regular mode
> doesn't even see them), but without lowmem --repair, I'm kind of screwed.
>
> I'm wondering if I could/should leave those errors unfixed until lowmem --repair
> finally happens, or whether I'm looking at spending another week rebuilding
> this filesystem :-/
>
>
> gargamel:~# btrfs check -p --mode lowmem  /dev/mapper/dshelf2
> Checking filesystem on /dev/mapper/dshelf2
> UUID: 85441c59-ad11-4b25-b1fe-974f9e4acede
> ERROR: extent[3886187384832, 81920] referencer count mismatch (root: 11930, owner: 375444, offset: 1851654144) wanted: 1, have: 4

This means that in extent tree, btrfs says there is only one referring 
to this extent, but lowmem mode find 4.

It would provide great help if you could dump extent tree for it.
# btrfs-debug-tree <dev> | grep -C 10 3886187384832


> ERROR: extent[3886189391872, 122880] referencer count mismatch (root: 11712, owner: 863395, offset: 79659008) wanted: 1, have: 2
> ERROR: extent[3933249708032, 69632] referencer count mismatch (root: 12424, owner: 6945, offset: 2083389440) wanted: 1, have: 2
> ERROR: extent[3933249708032, 69632] referencer count mismatch (root: 12172, owner: 6945, offset: 2083389440) wanted: 1, have: 2
> ERROR: extent[4571729862656, 876544] referencer count mismatch (root: 11058, owner: 375442, offset: 907706368) wanted: 6, have: 21
> ERROR: extent[4641490833408, 270336] referencer count mismatch (root: 11712, owner: 375444, offset: 1848672256) wanted: 3, have: 5
> ERROR: extent[4641490833408, 270336] referencer count mismatch (root: 11276, owner: 375444, offset: 1848672256) wanted: 3, have: 5
> ERROR: extent[4641490833408, 270336] referencer count mismatch (root: 11058, owner: 375444, offset: 1848672256) wanted: 3, have: 5
> ERROR: extent[4641490833408, 270336] referencer count mismatch (root: 11494, owner: 375444, offset: 1848672256) wanted: 3, have: 5
> ERROR: extent[4658555617280, 122880] referencer count mismatch (root: 11712, owner: 375444, offset: 1848705024) wanted: 1, have: 3
> ERROR: extent[4677858123776, 417792] referencer count mismatch (root: 11712, owner: 863395, offset: 79523840) wanted: 1, have: 3
> ERROR: extent[4677858123776, 417792] referencer count mismatch (root: 11930, owner: 863395, offset: 79523840) wanted: 1, have: 3
> ERROR: extent[4698380947456, 409600] referencer count mismatch (root: 11930, owner: 375444, offset: 1851596800) wanted: 3, have: 4
> ERROR: extent[4720470421504, 667648] referencer count mismatch (root: 11058, owner: 3463478, offset: 2334720) wanted: 2, have: 10
> ERROR: extent[4783941246976, 65536] referencer count mismatch (root: 9365, owner: 24493, offset: 4562944) wanted: 2, have: 3
> ERROR: extent[5077564477440, 106496] referencer count mismatch (root: 9370, owner: 1602694, offset: 734756864) wanted: 1, have: 2
> ERROR: extent[5136306929664, 131489792] referencer count mismatch (root: 11712, owner: 375441, offset: 910999552) wanted: 16, have: 1864
> ERROR: extent[5136306929664, 131489792] referencer count mismatch (root: 11276, owner: 375441, offset: 910999552) wanted: 867, have: 1865
> ERROR: extent[5136306929664, 131489792] referencer count mismatch (root: 11058, owner: 375441, offset: 910999552) wanted: 126, have: 1872
> ERROR: extent[5136306929664, 131489792] referencer count mismatch (root: 11494, owner: 375441, offset: 910999552) wanted: 866, have: 1864
> ERROR: extent[5136306929664, 131489792] referencer count mismatch (root: 11930, owner: 375441, offset: 910999552) wanted: 861, have: 1859
> ERROR: extent[5136649891840, 66781184] referencer count mismatch (root: 11058, owner: 375442, offset: 192659456) wanted: 5, have: 19
> ERROR: extent[5136879157248, 134217728] referencer count mismatch (root: 11930, owner: 375442, offset: 394543104) wanted: 10, have: 33
> ERROR: extent[5137380671488, 80945152] referencer count mismatch (root: 11058, owner: 375442, offset: 875233280) wanted: 1, have: 21
> ERROR: extent[5137380671488, 80945152] referencer count mismatch (root: 11930, owner: 375442, offset: 875233280) wanted: 11, have: 21
> ERROR: extent[5138641395712, 524288] referencer count mismatch (root: 11494, owner: 375445, offset: 39845888) wanted: 1, have: 3
> ERROR: extent[5190245990400, 53248] referencer count mismatch (root: 11712, owner: 863395, offset: 51118080) wanted: 1, have: 4
> ERROR: extent[5190245990400, 53248] referencer count mismatch (root: 11276, owner: 863395, offset: 51118080) wanted: 1, have: 4
> ERROR: extent[5190245990400, 53248] referencer count mismatch (root: 11494, owner: 863395, offset: 51118080) wanted: 1, have: 4
> ERROR: extent[5190274174976, 77824] referencer count mismatch (root: 11276, owner: 863395, offset: 74952704) wanted: 3, have: 5
> ERROR: extent[5190274174976, 77824] referencer count mismatch (root: 11058, owner: 863395, offset: 74952704) wanted: 3, have: 5
> ERROR: extent[5190274174976, 77824] referencer count mismatch (root: 11494, owner: 863395, offset: 74952704) wanted: 3, have: 5
> ERROR: extent[5190274174976, 77824] referencer count mismatch (root: 11930, owner: 863395, offset: 74952704) wanted: 3, have: 5
> ERROR: extent[5190275895296, 77824] referencer count mismatch (root: 11712, owner: 863395, offset: 77705216) wanted: 1, have: 6
> ERROR: extent[5190275895296, 77824] referencer count mismatch (root: 11276, owner: 863395, offset: 77705216) wanted: 5, have: 6
> ERROR: extent[5190275895296, 77824] referencer count mismatch (root: 11058, owner: 863395, offset: 77705216) wanted: 5, have: 6
> ERROR: extent[5427326599168, 61440] referencer count mismatch (root: 9370, owner: 1225712, offset: 29753344) wanted: 1, have: 5
> ERROR: extent[5456623030272, 24576] referencer count mismatch (root: 11058, owner: 2278892, offset: 786432) wanted: 2, have: 3
> ERROR: extent[5851251269632, 134217728] referencer count mismatch (root: 9370, owner: 1602695, offset: 534061056) wanted: 3, have: 4
> ERROR: errors found in extent allocation tree or chunk allocation
> cache and super generation don't match, space cache will be invalidated
> ERROR: root 3857 EXTENT_DATA[108864 4096] interrupt

This means that, for root 3857, inode 108864, file offset 4096, there is 
a gap before that extent.
In NO_HOLES mode it's allowed, but if NO_HOLES incompat flag is not set, 
this should be a problem.

I wonder if this is a problem caused by inlined compressed file extent.

This can also be dumped by the following command.
# btrfs-debug-tree -t 3857 <dev> | grep -C 10 108864

Thanks,
Qu

> ERROR: root 3857 EXTENT_DATA[133050 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[388570 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[729583 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[984778 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[997394 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1002954 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1007491 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1111463 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1111506 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1111536 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1111536 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1134500 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1136498 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1175965 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1185977 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1190919 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1201340 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1230370 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1230530 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1230530 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1235960 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1248784 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1271827 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1295242 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1406074 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1410780 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1412938 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1413532 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1413532 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1421245 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1423365 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1425985 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1429229 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1430615 4096] interrupt
> ERROR: root 3857 EXTENT_DATA[1443769 4096] interrupt
> ERROR: root 3860 EXTENT_DATA[599089 4096] interrupt
>
> (not finished, still going on)
>
> Marc


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