Hello, Please be aware that there seems to be a possible problem with using NOCOW flag on files situated on a filesystem mounted with compress-force(=lzo, in my case). Since experimenting with NOCOW, I started regularly hitting this BUG at extent-tree.c:5813 5813 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); I was unable to make netconsole work over a bridged interface, so can only post screenshots of this OOPS: http://romanrm.ru/pics/2012/2012-02-16-btrfs-bug-1.jpg http://romanrm.ru/pics/2012/2012-02-16-btrfs-bug-2.jpg This happened four times already, and always on snapshot creation (but not every case). I have hourly snapshots in crontab, and only one case out of about ten fails with this problem. Did not try to deliberately reproduce it yet by manually making snapshots very often, etc. On Mon, 13 Feb 2012 15:10:40 +0100 David Sterba wrote: > Hi, > > On Mon, Feb 13, 2012 at 04:40:03PM +0900, dima wrote: > > Actually it is possible. Check out David's response to my question from > > some time ago: > > http://permalink.gmane.org/gmane.comp.file-systems.btrfs/14227 > > this was a quick aid, please see attached file for an updated tool to set > the file flags, now added 'z' for NOCOMPRESS flag, and supports chattr > syntax plus all of the standard file flags. > > Setting and unsetting nocow is done like 'fileflags +C file' or -C for > unseting. Without any + or - options it prints current state. > > > david -- With respect, Roman ~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Stallman had a printer, with code he could not see. So he began to tinker, and set the software free."