On Thursday, February 03, 2011, Martin Steigerwald wrote:

Added linux-btrfs and Helmut Hullen, who seemed to experience hangs on a 
T23 with BTRFS as well, to Cc.

Am Thursday 03 February 2011 schrieb Rafael J. Wysocki:

quoted

This message has been generated automatically as a part of a report
of regressions introduced between 2.6.36 and 2.6.37.

The following bug entry is on the current list of known regressions
introduced between 2.6.36 and 2.6.37.  Please verify if it still should
be listed and let the tracking team know (either way).


Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=27842
Subject		: [regression?] hang with 2.6.37 on a BTRFS test machine
Submitter	: Martin Steigerwald [off-list ref]
Date		: 2011-01-23 12:06 (11 days old)
Message-ID	: [ref]
References	: http://marc.info/?l=linux-kernel&m=129578445613283&w=2

Well I now tested with 2.6.36 for more than a week and I did not see any 
of such hangs upto now. The machine seems table with 2.6.36. So I think 
its really an regression of 2.6.37.

I am stuck with what to try next. Since trying to track it down to a 
specific commit appears too involved for me and its appears also quite 
laborious to get any value debug information out of the kernel - cause it 
can take days for the bug to appear -, I am inclined to either test with 
2.6.37.1 once its available or just give it a go with 2.6.38-rc3 or rc4. 
Maybe 2.6.38-rc3/4 would be the best bet, I have seen a report on the 
btrfs mailing list of 2.6.38 fixing a BTRFS hang bug that appeared with 
2.6.37. I am just not sure whether its related or not.

Re: [PATCH v2]Btrfs: pwrite blocked when writing from the mmaped buffer of 
the same page
http://marc.info/?l=linux-btrfs&m=129623925116051&w=2

There is another thread about 2.6.37 related BTRFS hang:

flush-btrfs-1 hangs when building openwrt
http://marc.info/?l=linux-btrfs&m=129594547616298&w=2

I will add this as comment to the bug report as well.

Thanks for the update.

Rafael