Re: btrfs-image failure (btrfs-tools 4.4)

[Marc MERLIN <marc@merlins.org>]

On Thu, Feb 11, 2016 at 03:16:47PM +0800, Qu Wenruo wrote:
> >I started making a dump, image was growing past 3GB, and then it failed
> >and the image got deleted:
> >
> >gargamel:~# btrfs-image -s -c 9 /dev/mapper/dshelf1old /mnt/dshelf1/ds1old.dump
> >Error adding space cache blocks -5
> 
> It seems that btrfs-image failed to read space cache, in
> read_data_extent() function.
> 
> And since there is no "Couldn't map the block XXXX" error message,
> either some device is missing or pread64 failed to read the desired
> data.
 
It's a 5 drive raid5 underneath, all drives are there.

> >Is there a 4G file size limit, or did I hit another problem?
> 
> For the 4G file size limit, did you mean the limit from old
> filesystem like FAT32?
 
No, I wrote on btrfs, so it's not a filesystem limit, but I meant that
maybe if there was a 32bit pointer somewhere, it could have caused this.
I did use the 64bit version of the tools on a 64bit kernel though, so I
don't see why it could have happened.

> I didn't think there is such limit for modern Linux filesystem, or
> normal read/write operation won't has such limit either.

Agreed.

At this point, is there anything else I should get/do before I wipe this
filesystem?

Thanks,
Marc
-- 
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