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From: Alex Lyakas <alex.btrfs@zadarastorage.com>
To: Jan Schmidt <list.btrfs@jan-o-sch.net>,
	linux-btrfs <linux-btrfs@vger.kernel.org>
Cc: Arne Jansen <sensille@gmx.net>,
	Alexander Block <ablock84@googlemail.com>
Subject: backref for an extent not found in send_root (!backref_ctx->found_itself)
Date: Mon, 28 Jan 2013 18:11:08 +0200	[thread overview]
Message-ID: <CAOcd+r36TOugPs+5P3W6v6m5pzojGnqZ3YUNS-zzFK2pdm1A8A@mail.gmail.com> (raw)

Hi Jan,
I have a set of unit tests (part of the larger system) for the
send-receive functionality, with which I am able to hit this error:

Jan 28 18:01:00 687-dev kernel: [16968.451358] btrfs: ERROR did not
find backref in send_root. inode=259, offset=139264, disk_byte=4263936
found extent=4263936

As the code states, this could indicate a bug in backref walking. This
reproduces with "for-linus" branch.

Typically this happens when a snapshot is deleted, immediately a new
snap with the same name is created, and then "btrfs send" is issued
without parent (i.e., full-send) on this snap.

To debug this further, we can do one of two things:
# I can apply patches/debug prints & reproduce
# I can work to isolate the unit test into a bash script and send you
a script that reproduces

Please let me know.

Thanks,
Alex.

             reply	other threads:[~2013-01-28 16:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-28 16:11 Alex Lyakas [this message]
2013-01-29  9:07 ` backref for an extent not found in send_root (!backref_ctx->found_itself) Jan Schmidt
2013-01-31 19:24   ` Alex Lyakas
2013-02-19  7:58     ` Alex Lyakas
2013-02-19  8:11       ` Jan Schmidt
2013-02-21 15:35 ` [PATCH] Btrfs: fix backref walking race with tree deletions Jan Schmidt
2013-03-12 11:47   ` Alex Lyakas
2013-03-19 16:32     ` Jan Schmidt

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