On 2017-06-21 08:43, Christoph Anton Mitterer wrote:
On Wed, 2017-06-21 at 16:45 +0800, Qu Wenruo wrote:
Btrfs is always using device ID to build up its device mapping.
And for any multi-device implementation (LVM,mdadam) it's never a
good
idea to use device path.
Isn't it rather the other way round? Using the ID is bad? Don't you
remember our discussion about using leaked UUIDs (or accidental
collisions) for all kinds of attacks?
Both are bad for different reasons. For the particular case of sanely
handling transient storage failures (device disappears then reappears),
you can't do it with a path in /dev (which is what most people mean when
they say device path), and depending on how the hardware failed and the
specifics of the firmware, you may not be able to do it with a
hardware-level device path, but you can do it with a device ID assuming
you sanely verify the ID. Right now, BTRFS is not sanely checking the
ID (it only verifies the UUID's in the FS itself, it should also be
checking hardware-level identifiers like WWN).
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