On Wed, Aug 15, 2012 at 11:02:31AM +0800, Liu Bo wrote:

On 08/15/2012 10:48 AM, Marc MERLIN wrote:

quoted

On Tue, Aug 14, 2012 at 11:23:14AM -0700, Marc MERLIN wrote:

quoted

My laptop oopsed due to a wireless bug

When I rebooted, the system came back ok, and seemed to work, but soon went
to read only with the error in the subject line.

I have hourly snapshots for each of the 5 subvolumes in that btrfs
filesystem.

How do I recover from this? Revert all the snapshots one hour, find/guess
which one caused the problem somehow and revert just that one? (the error
message didn't give a subvolume or directory).

Also, before I do this, is there debug info I can get off my system?

I'm likely to have to do this tonight to get back to a working system.

If someone wants debug info before I lose it potentially, please ask soon ;)

What does the 'ret' shows?  Is it -ENOSPC?

I got nothing else in my logs.

I powered the laptop back on and it came up like nothing ever happened.

[   15.626700] device label btrfs_pool1 devid 1 transid 10222 /dev/mapper/cryptroot
[   15.627161] btrfs: disk space caching is enabled
[   15.631704] btrfs: bdev /dev/mapper/cryptroot errs: wr 0, rd 0, flush 0, corrupt 0, gen 0

It looks like the SSD was loose inside the laptop (the tray that holds it isn't quite the
right size it seems).
I think it may not have had a good connection, but what's interesting is that I 
got absolutely no lower level errors in dmesg (which didn't get written to disk).

All that said, I think it may just have been a write error due to a hardware 
connection problem (no way to prove this now).
If there is nothing suspicious in the code around that line, let's just ignore 
my report.

For what it's worth, I do have plenty of space left:
Label: 'btrfs_pool1'  uuid: 92584fa9-85cd-4df6-b182-d32198b76a0b
	Total devices 1 FS bytes used 227.44GB
	devid    1 size 441.70GB used 297.04GB path /dev/dm-0

Thanks for your reply.
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/