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From: Doni Crosby <doni.crosby1995@gmail.com>
To: lists@colorremedies.com
Cc: linux-btrfs@vger.kernel.org
Subject: Re: System unable to mount partition after a power loss
Date: Fri, 7 Dec 2018 01:43:38 -0500	[thread overview]
Message-ID: <CAJkMDByx_H3xjJmN4gO+L0pxpkd7sWLTmTxRfNjUp06r8o3E7w@mail.gmail.com> (raw)
In-Reply-To: <CAJCQCtSiYk4RMRWRoaAFchzvinQ4tq1wC_Ru9d8gJWRsebvbTw@mail.gmail.com>

[-- Attachment #1: Type: text/plain, Size: 3921 bytes --]

> This is qemu-kvm? What's the cache mode being used? It's possible the
> usual write guarantees are thwarted by VM caching.
Yes it is a proxmox host running the system so it is a qemu vm, I'm
unsure on the caching situation.

> Old version of progs, I suggest upgrading to 4.17.1 and run
I updated the progs to 4.17 and ran the following

btrfs insp dump-s -f /device/:
See attachment

btrfs rescue super -v /device/ (insp rescue super wasn't valid)
All Devices:
        Device: id = 1, name = /dev/vda1

Before Recovering:
        [All good supers]:
                device name = /dev/vda1
                superblock bytenr = 65536

                device name = /dev/vda1
                superblock bytenr = 67108864

                device name = /dev/vda1
                superblock bytenr = 274877906944

        [All bad supers]:

All supers are valid, no need to recover

btrfs check --mode=lowmem /dev/vda1:
parent transid verify failed on 3563224121344 wanted 5184691 found 5184688
parent transid verify failed on 3563224121344 wanted 5184691 found 5184688
parent transid verify failed on 3563221630976 wanted 5184691 found 5184688
parent transid verify failed on 3563221630976 wanted 5184691 found 5184688
parent transid verify failed on 3563223138304 wanted 5184691 found 5184688
parent transid verify failed on 3563223138304 wanted 5184691 found 5184688
parent transid verify failed on 3563224072192 wanted 5184691 found 5184688
parent transid verify failed on 3563224072192 wanted 5184691 found 5184688
parent transid verify failed on 3563225268224 wanted 5184691 found 5184689
parent transid verify failed on 3563225268224 wanted 5184691 found 5184689
parent transid verify failed on 3563227398144 wanted 5184691 found 5184689
parent transid verify failed on 3563227398144 wanted 5184691 found 5184689
parent transid verify failed on 3563229593600 wanted 5184691 found 5184689
parent transid verify failed on 3563229593600 wanted 5184691 found 5184689
parent transid verify failed on 3563229593600 wanted 5184691 found 5184689
parent transid verify failed on 3563229593600 wanted 5184691 found 5184689
Ignoring transid failure
ERROR: child eb corrupted: parent bytenr=3563210342400 item=120 parent
level=1 child level=1
ERROR: cannot open file system

mount -o ro,norecovery,usebackuproot /dev/vda1 /mnt:
Same dmesg output as before.
On Fri, Dec 7, 2018 at 12:56 AM Chris Murphy <lists@colorremedies.com> wrote:
>
> On Thu, Dec 6, 2018 at 10:24 PM Doni Crosby <doni.crosby1995@gmail.com> wrote:
> >
> > All,
> >
> > I'm coming to you to see if there is a way to fix or at least recover
> > most of the data I have from a btrfs filesystem. The system went down
> > after both a breaker and the battery backup failed. I cannot currently
> > mount the system, with the following error from dmesg:
> >
> > Note: The vda1 is just the entire disk being passed from the VM host
> > to the VM it's not an actual true virtual block device
>
> This is qemu-kvm? What's the cache mode being used? It's possible the
> usual write guarantees are thwarted by VM caching.
>
>
>
> > btrfs check --recover also ends in a segmentation fault
>
> I'm not familiar with --recover option, the --repair option is flagged
> with a warning in the man page.
>            Warning
>            Do not use --repair unless you are advised to do so by a
> developer or an experienced user,
>
>
> > btrfs --version:
> > btrfs-progs v4.7.3
>
> Old version of progs, I suggest upgrading to 4.17.1 and run
>
> btrfs insp dump-s -f /device/
> btrfs insp rescue super -v /device/
> btrfs check --mode=lowmem /device/
>
> These are all read only commands. Please post output to the list,
> hopefully a developer will get around to looking at it.
>
> It is safe to try:
>
> mount -o ro,norecovery,usebackuproot /device/ /mnt/
>
> If that works, I suggest updating your backup while it's still
> possible in the meantime.
>
>
> --
> Chris Murphy

[-- Attachment #2: btrfs-insp.txt --]
[-- Type: text/plain, Size: 5349 bytes --]

superblock: bytenr=65536, device=/dev/vda1
---------------------------------------------------------
csum_type               0 (crc32c)
csum_size               4
csum                    0xbfa6fd72 [match]
bytenr                  65536
flags                   0x1
                        ( WRITTEN )
magic                   _BHRfS_M [match]
fsid                    7c76bb05-b3dc-4804-bf56-88d010a214c6
label                   Array
generation              5184693
root                    31801344
sys_array_size          226
chunk_root_generation   5183734
root_level              1
chunk_root              20971520
chunk_root_level        1
log_root                0
log_root_transid        0
log_root_level          0
total_bytes             32003947737088
bytes_used              6652776640512
sectorsize              4096
nodesize                16384
leafsize (deprecated)           16384
stripesize              4096
root_dir                6
num_devices             1
compat_flags            0x0
compat_ro_flags         0x0
incompat_flags          0x161
                        ( MIXED_BACKREF |
                          BIG_METADATA |
                          EXTENDED_IREF |
                          SKINNY_METADATA )
cache_generation        5184691
uuid_tree_generation    5184691
dev_item.uuid           e0543326-f76c-4409-98dc-98a782a75490
dev_item.fsid           7c76bb05-b3dc-4804-bf56-88d010a214c6 [match]
dev_item.type           0
dev_item.total_bytes    32003947737088
dev_item.bytes_used     6744210145280
dev_item.io_align       4096
dev_item.io_width       4096
dev_item.sector_size    4096
dev_item.devid          1
dev_item.dev_group      0
dev_item.seek_speed     0
dev_item.bandwidth      0
dev_item.generation     0
sys_chunk_array[2048]:
        item 0 key (FIRST_CHUNK_TREE CHUNK_ITEM 0)
                length 4194304 owner 2 stripe_len 65536 type SYSTEM
                io_align 4096 io_width 4096 sector_size 4096
                num_stripes 1 sub_stripes 0
                        stripe 0 devid 1 offset 0
                        dev_uuid e0543326-f76c-4409-98dc-98a782a75490
        item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 20971520)
                length 8388608 owner 2 stripe_len 65536 type SYSTEM|DUP
                io_align 65536 io_width 65536 sector_size 4096
                num_stripes 2 sub_stripes 0
                        stripe 0 devid 1 offset 20971520
                        dev_uuid e0543326-f76c-4409-98dc-98a782a75490
                        stripe 1 devid 1 offset 29360128
                        dev_uuid e0543326-f76c-4409-98dc-98a782a75490
backup_roots[4]:
        backup 0:
                backup_tree_root:       3563189026816   gen: 5184690    level: 1
                backup_chunk_root:      20971520        gen: 5183734    level: 1
                backup_extent_root:     3563188224000   gen: 5184690    level: 2
                backup_fs_root:         3563187421184   gen: 5184690    level: 2
                backup_dev_root:        7413296562176   gen: 5183734    level: 1
                backup_csum_root:       3563187732480   gen: 5184690    level: 3
                backup_total_bytes:     32003947737088
                backup_bytes_used:      6652776640512
                backup_num_devices:     1

        backup 1:
                backup_tree_root:       3563196792832   gen: 5184691    level: 1
                backup_chunk_root:      20971520        gen: 5183734    level: 1
                backup_extent_root:     3563193925632   gen: 5184691    level: 2
                backup_fs_root:         3563190501376   gen: 5184691    level: 2
                backup_dev_root:        7413296562176   gen: 5183734    level: 1
                backup_csum_root:       3563190648832   gen: 5184691    level: 3
                backup_total_bytes:     32003947737088
                backup_bytes_used:      6652776640512
                backup_num_devices:     1

        backup 2:
                backup_tree_root:       3563187781632   gen: 5184688    level: 1
                backup_chunk_root:      20971520        gen: 5183734    level: 1
                backup_extent_root:     3563185471488   gen: 5184688    level: 2
                backup_fs_root:         3563179261952   gen: 5184688    level: 2
                backup_dev_root:        7413296562176   gen: 5183734    level: 1
                backup_csum_root:       3563183734784   gen: 5184688    level: 3
                backup_total_bytes:     32003947737088
                backup_bytes_used:      6652776640512
                backup_num_devices:     1

        backup 3:
                backup_tree_root:       3563187617792   gen: 5184689    level: 1
                backup_chunk_root:      20971520        gen: 5183734    level: 1
                backup_extent_root:     3563186143232   gen: 5184689    level: 2
                backup_fs_root:         3563183833088   gen: 5184689    level: 2
                backup_dev_root:        7413296562176   gen: 5183734    level: 1
                backup_csum_root:       3563184963584   gen: 5184689    level: 3
                backup_total_bytes:     32003947737088
                backup_bytes_used:      6652776640512
                backup_num_devices:     1

  reply	other threads:[~2018-12-07  6:43 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-07  5:24 System unable to mount partition after a power loss Doni Crosby
2018-12-07  5:56 ` Chris Murphy
2018-12-07  6:43   ` Doni Crosby [this message]
2018-12-07 12:24     ` Austin S. Hemmelgarn
2018-12-07 16:31       ` Doni Crosby
2018-12-07  7:22 ` Qu Wenruo
     [not found]   ` <CAJkMDBxD89DFYxV3Nc8EqKDupcxM2+kNGLtTo6QDWaTz-juT6g@mail.gmail.com>
2018-12-07 17:31     ` Doni Crosby

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