From: "Swâmi Petaramesh" <swami@petaramesh.org>
To: linux-btrfs@vger.kernel.org
Subject: mount options ignored / unclear
Date: Fri, 11 Apr 2014 11:21:55 +0200 [thread overview]
Message-ID: <1988570.7Waz7R0erI@zafu> (raw)
Hello,
(Still in my quest for BTRFS performance)
It is extremely unclear which BTRFS mount options are "filesystem wide" and
will apply to each and every mountpoint in the BTRFS filesystem, and which
options can be set per subvolume or per mountpoint.
As far as I can tell, there is no reliable documentation about this, is there
any ?
(Kernel is 3.13, Fedora)
i.e. I have in fstab :
/dev/sda3 / btrfs subvol=FEDORA,noatime,compress=lzo,autodefrag
...So without suprise I get in /proc/self/mountinfo:
36 1 0:32 /FEDORA / rw,noatime shared:1 - btrfs /dev/sda3
rw,seclabel,compress=lzo,space_cache,autodefrag
...But then I have in fstab:
/dev/sda3 /home/me/.cache btrfs
subvol=/NOCOW/me/.cache,nodatacow,compress=no,noatime
So it is with great suprise the I get in /proc/self/mountinfo:
49 47 0:32 /NOCOW/me/.cache /home/me/.cache rw,noatime shared:33 - btrfs
/dev/sda3 rw,seclabel,compress=lzo,space_cache,autodefrag
...I'm not suprised to see "space_cache" which I would assume to be FS-wide,
but what the hell does "autodefrag" do in there, or even worse "compress=lzo",
where "compress=no" has been exlicitely specified in fstab ?
That's a bug, as far as I can tell.
Kind regards.
--
Swâmi Petaramesh <swami@petaramesh.org> http://petaramesh.org PGP 9076E32E
next reply other threads:[~2014-04-11 9:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-11 9:21 Swâmi Petaramesh [this message]
2014-04-12 4:42 ` mount options ignored / unclear Duncan
-- strict thread matches above, loose matches on Subject: below --
2014-04-12 20:05 Chris Murphy
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