On Tue, 14 Feb 2017 10:30:43 -0500 "Austin S. Hemmelgarn" <ahferro...@gmail.com> wrote:
> I was just experimenting with snapshots on 4.9.0, and came across some > unexpected behavior. > > The simple explanation is that if you snapshot a subvolume, any files in > the subvolume that have the NOCOW attribute will not have that attribute > in the snapshot. Some further testing indicates that this is the only > file attribute that isn't preserved (I checked all the chattr flags that > BTRFS supports). > > I'm kind of curious whether: > 1. This is actually documented somewhere, as it's somewhat unexpected > given that everything else is preserved when snapshotting. > 2. This is intended behavior, or just happens to be a side effect of the > implementation. I don't seem to get this on 4.4.45 and 4.4.47. $ btrfs sub create test Create subvolume './test' $ touch test/abc $ chattr +C test/abc $ echo def > test/abc $ ls -la test/abc -rw-r--r-- 1 rm rm 4 Feb 14 20:52 test/abc $ lsattr test/abc ---------------C test/abc $ btrfs sub snap test test2 Create a snapshot of 'test' in './test2' $ ls -la test2/abc -rw-r--r-- 1 rm rm 4 Feb 14 20:52 test2/abc $ lsattr test2/abc ---------------C test2/abc -- With respect, Roman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
