On 2017-02-14 11:46, Austin S. Hemmelgarn wrote:
On 2017-02-14 11:07, Chris Murphy wrote:
On Tue, Feb 14, 2017 at 8:30 AM, Austin S. Hemmelgarn
<ahferroin7@xxxxxxxxx> 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).
Huh, I can't reproduce this with 4.9.8 or 4.10rc7. systemd sets
journal files with chattr +C, and I do manual snapshots of rootfs
periodically, and those snapshots have journal files that have +C
still set.
Just tested on a different filesystem, and I'm not seeing it there
either, I'll take a closer look at the FS I saw this on and see if I can
figure out what's up.
After poking around a bit further, the system crashed, and it looks like
there was some memory corruption scattered throughout the kernel from
one of the other modules I had loaded (now I get to spend a day or more
figuring out which one and reporting that bug). Given the state of the
kernel crash dump though, I'm actually somewhat surprised that things
weren't misbehaving more spectacularly than this.
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