On Thu, Apr 17, 2014 at 09:17:03AM +0800, Qu Wenruo wrote:
> But after some tests, it seems that the ctime/mtime based cache seems not
> perfect due to the fact that multiple
Yes, the cache is not perfect -- it was originally introduced by Ted
in time when things was less complicated :-) The current goal is to
avoid the cache usage, so we have low-level API in libblkid to bypass
the cache at all, and in userspace we use this API or udev db. I guess
that many users have the cache empty, because it's unnecessary for
fsck, mount, lsblk, findmnt, systemd etc.
> device file can be created in different fs with same major/minor number.
> especially each of them has individual ctime/mtime timestamp.
>
> So if someone (maybe insane) use mknod to create as block device file and
> use 'btrfs dev del' on the newly created
> block device file, libblkid will still be unable to detect the change since
> the ctime/mtime of block device file in /dev/
> does not change.
Not sure if I understand, it would be nice to have complete example.
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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