Mysterious device (id 0).

DISCUSSION Christian 3 participants 7 messages May 15, 2015 Btrfs file system

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Christian

author

2015-05-15 00:09 UTC #0 lore raw

Hi,

My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3

When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:

scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710
scrub device /dev/sda3 (id 1) history
scrub started at Thu May 14 19:54:02 2015 and finished after 235 seconds total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0 seconds total bytes scrubbed: 0.00B with 0 errors

As device (id 0) is indicated, but I have no idea what it is.

When I run scrub with a script (cron) the same device (id 0) shows up in a warning:

/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors

What is this device (id 0) which never gets scrubbed but always shows up?

I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.

P.S. I am not a developer.

Signature · 1 line

//Christian

Austin S Hemmelgarn

2015-05-15 11:25 UTC #1 lore raw

Quoted 34 lines · Christian

Hi,
My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3
When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:
scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710 scrub device /dev/sda3 (id 1) history
     scrub started at Thu May 14 19:54:02 2015 and finished after 235
seconds
total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
As device (id 0) is indicated, but I have no idea what it is.
When I run scrub with a script (cron) the same device (id 0) shows up in a warning:
/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors

Quoted 4 lines

What is this device (id 0) which never gets scrubbed but always shows up?
I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.

Have you ever run 'btrfs replace' to replace a device in the filesystem?
I know that new device in a replace operation get's tagged as device
id 0 until the replace operation completes (at which point it gets the devid of the device it replaced). Personally, this is the only case that I know of that devid 0 is actually used in the code. Thinking further though, it might also be an off-by-one error somewhere, although I have no idea where.

Christian

author

2015-05-15 15:36 UTC #2 lore raw

Quoted 39 lines · Austin S Hemmelgarn

Quoted 34 lines · Christian
Hi,
My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3
When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:
scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710 scrub device /dev/sda3 (id 1) history
     scrub started at Thu May 14 19:54:02 2015 and finished after 235
seconds
total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
As device (id 0) is indicated, but I have no idea what it is.
When I run scrub with a script (cron) the same device (id 0) shows up in a warning:
/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
Quoted 4 lines
What is this device (id 0) which never gets scrubbed but always shows up?
I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.

Quoted 9 lines

Have you ever run 'btrfs replace' to replace a device in the filesystem?
I know that new device in a replace operation get's tagged as device
id 0 until the replace operation completes (at which point it gets the devid of the device it replaced). Personally, this is the only case that I know of that devid 0 is actually used in the code. Thinking further though, it might also be an off-by-one error somewhere, although I have no idea where.

No, I have never run 'btrfs replace'. This problem was discussed in a previous thread covering the script I am using for daily scrub. The author had the same problem, but for him it simply went away. Not for me though. The thread was

"Re: 3.19.3: check tree block failed + WARNING: device 0 not present on scrub".

I have had some problems with btrfs in the past so I am very ware of any error message! I can't live without the snapshots anymore though :)

Signature · 1 line

//Christian

Anand Jain

2015-05-15 16:20 UTC #3 lore raw

In reply to Christian

Quoted 10 lines · Christian

Hi,
My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3
When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:
scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710 scrub device /dev/sda3 (id 1) history

Quoted 7 lines

     scrub started at Thu May 14 19:54:02 2015 and finished after 235
seconds
total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors

we are reading an uninitialized device struct and that uninitialized devid happens to be 0. looks like num_devices count went haywire.

in this config was there any device delete ? or a reduce in # of devices? and has the system been rebooted after that ?

Thanks, Anand

Quoted 22 lines

As device (id 0) is indicated, but I have no idea what it is.
When I run scrub with a script (cron) the same device (id 0) shows up in a warning:
/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
What is this device (id 0) which never gets scrubbed but always shows up?
I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.
P.S. I am not a developer.

Christian

author

2015-05-15 16:37 UTC #4 lore raw

Quoted 21 lines · Anand Jain

Quoted 10 lines · Christian
Hi,
My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3
When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:
scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710 scrub device /dev/sda3 (id 1) history
Quoted 7 lines
     scrub started at Thu May 14 19:54:02 2015 and finished after 235
seconds
total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors

Quoted 7 lines

we are reading an uninitialized device struct and that uninitialized devid happens to be 0. looks like num_devices count went haywire.
in this config was there any device delete ? or a reduce in # of devices? and has the system been rebooted after that ?
Thanks, Anand

Not sure I understand fully what you are asking, but I deleted a swap partition on the drive a while back and increased the size of the btrfs partition (with gparted). I have rebooted many times since then. That is all the changes I have done to this SSD recently.

Thanks.

Quoted 25 lines

Quoted 18 lines
As device (id 0) is indicated, but I have no idea what it is.
When I run scrub with a script (cron) the same device (id 0) shows up in a warning:
/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
Quoted 6 lines
What is this device (id 0) which never gets scrubbed but always shows up?
I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.
P.S. I am not a developer.
--

Signature · 1 line

//Christian

Anand Jain

2015-05-15 16:51 UTC #5 lore raw

Quoted 28 lines · Christian

Quoted 27 lines · Anand Jain
Quoted 10 lines · Christian
Hi,
My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3
When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:
scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710 scrub device /dev/sda3 (id 1) history
Quoted 7 lines
     scrub started at Thu May 14 19:54:02 2015 and finished after 235
seconds
total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
we are reading an uninitialized device struct and that uninitialized devid happens to be 0. looks like num_devices count went haywire.
in this config was there any device delete ? or a reduce in # of devices? and has the system been rebooted after that ?

Quoted 6 lines

Quoted 1 line
Thanks, Anand
Not sure I understand fully what you are asking, but I deleted a swap partition on the drive a while back and increased the size of the btrfs partition (with gparted). I have rebooted many times since then. That is all the changes I have done to this SSD recently.

ok got it. now do you have any other disk in the system with the same fsid ? what does the btrfs fi show -d or blkid show.

Thanks

Quoted 30 lines

Thanks.
Quoted 26 lines
Quoted 18 lines
As device (id 0) is indicated, but I have no idea what it is.
When I run scrub with a script (cron) the same device (id 0) shows up in a warning:
/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
Quoted 7 lines
What is this device (id 0) which never gets scrubbed but always shows up?
I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.
P.S. I am not a developer.
--

Christian

author

2015-05-15 17:17 UTC #6 lore raw

Quoted 38 lines · Anand Jain

Quoted 28 lines · Christian
Quoted 27 lines · Anand Jain
Quoted 10 lines · Christian
Hi,
My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs partition containing / and /home as a sub volume /dev/sda3
When I run scrub on /dev/sda3 and check status with sudo btrfs scrub status -d /dev/sda3 I get:
scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710 scrub device /dev/sda3 (id 1) history
Quoted 7 lines
     scrub started at Thu May 14 19:54:02 2015 and finished after 235
seconds
total bytes scrubbed: 111.03GiB with 0 errors
scrub device (id 0) history
scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
we are reading an uninitialized device struct and that uninitialized devid happens to be 0. looks like num_devices count went haywire.
in this config was there any device delete ? or a reduce in # of devices? and has the system been rebooted after that ?
Quoted 6 lines
Quoted 1 line
Thanks, Anand
Not sure I understand fully what you are asking, but I deleted a swap partition on the drive a while back and increased the size of the btrfs partition (with gparted). I have rebooted many times since then. That is all the changes I have done to this SSD recently.

Quoted 4 lines

ok got it. now do you have any other disk in the system with the same fsid ? what does the btrfs fi show -d or blkid show.
Thanks

btrfs fi show -d
Label: none uuid: 3d52dc93-c89f-453f-965d-8601d11e7710

	Total devices 1 FS bytes used 108.94GiB
	devid    1 size 222.84GiB used 111.03GiB path /dev/sda3

blkid
/dev/sda1: UUID="82348a5a-6c11-47dc-a4aa-884431c7cc1a" TYPE="ext4" PARTUUID="8e3b64c9-0f7d-4720-be83-8de7a63ec246"
/dev/sda3: UUID="3d52dc93-c89f-453f-965d-8601d11e7710" UUID_SUB="91c64b93-2eb7-4e98-b940-57a2ae3edd6e" TYPE="btrfs" PARTUUID="40fcadee-050e-4f5d-8538-6abdfc57c7b8"

It probably doesn't matter but the drive is an INTEL SSD on a Lenovo Thinkpad X1 Carbon with Ubuntu 15.04

Quoted 34 lines

Quoted 33 lines
Thanks.
Quoted 27 lines
Quoted 19 lines
As device (id 0) is indicated, but I have no idea what it is.
When I run scrub with a script (cron) the same device (id 0) shows up in
a warning:
/etc/cron.daily/btrfs-scrub:
WARNING: device 0 not present
scrub device /dev/sda3 (id 1) done
scrub started at Sat May 2 08:03:46 2015 and finished after 241
seconds
total bytes scrubbed: 109.06GiB with 0 errors
scrub device (id 0) canceled
scrub started at Sat May 2 08:03:46 2015 and was aborted after 0
seconds
total bytes scrubbed: 0.00B with 0 errors
Quoted 7 lines
What is this device (id 0) which never gets scrubbed but always shows up?
I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.
P.S. I am not a developer.
--
--

Signature · 1 line

//Christian