From: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
To: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Cosmetics bug: remounting ssd does not clear nossd
Date: Fri, 31 Mar 2017 01:01:28 +0200 [thread overview]
Message-ID: <0939c5df-3abd-ec68-16ef-538ad04251aa@mendix.com> (raw)
If I have a filesystem that shows this...
rw,relatime,ssd,space_cache=v2,subvolid=5,subvol=/
...and then I do this...
-# mount -o remount,nossd /mnt/btrfs/
...then it shows...
rw,relatime,nossd,space_cache=v2,subvolid=5,subvol=/
...but when I do this...
-# mount -o remount,ssd /mnt/btrfs/
...it ends up with a rotational identity crisis:
rw,relatime,nossd,ssd,space_cache=v2,subvolid=5,subvol=/
^^^^^ ^^^
The only thing the nossd option does when mounting first time is
preventing that ssd gets enabled automatically. When doing nossd with
remount, it clears out the ssd flag, but telling it to ssd again does
not clear the nossd flag.
The actual kernel code which changes behaviour based on these options
only ever checks for SSD, never for NOSSD.
So, the situation does not lead to any wrong behaviour right now, but
it's confusing, and it could be a source of bugs in the future, when
anything would test for NOSSD explicitely and make a decision based on
the result.
Moo,
--
Hans van Kranenburg
next reply other threads:[~2017-03-30 23:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-30 23:01 Hans van Kranenburg [this message]
2017-03-31 15:19 ` [PATCH] btrfs: drop the nossd flag when remounting with -o ssd Adam Borowski
2017-03-31 16:00 ` Hans van Kranenburg
2017-03-31 17:10 ` David Sterba
2017-03-31 20:08 ` [PATCH v2] " Adam Borowski
2017-03-31 20:24 ` Hans van Kranenburg
2017-03-31 20:43 ` Adam Borowski
2017-03-31 20:50 ` Hans van Kranenburg
2017-04-03 12:24 ` David Sterba
2017-04-03 22:43 ` Hans van Kranenburg
2017-04-10 17:35 ` David Sterba
2017-04-03 12:25 ` David Sterba
2017-04-15 19:12 ` [PATCH] " Hans van Kranenburg
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