Goffredo Baroncelli
2011-Oct-21 17:36 UTC
Avoid error message during a scan of a static /dev directory
Hi all,
as highlighted by Helmut (see "Re: btrfs still looks for not existing
devices"), some btrfs tools (like mkfs.btrfs, btrfsck, btrfs-image, btrfs-
label...) have the habit to scan the /dev directories looking for a valid
block device in order to assemble all the devices of a btrfs filesystems.
Some systems doesn''t use udev, so they have a static /dev with a lot of
block
device nodes without a real device. Another source of error is that some
devices return ENOMEDIUM (No medium found) when they haven''t a medium
(think
about a CD with the tray empty, or a SD/CF reader). These two kind of errors
are reported by these tools.
I think that it is perfectly safe to ignore these error because the fact that
a device doesn''t exist or a CD is empty is not an error which should be
handled and/or reported when the system is trying to assemble the devices for
a filesystem.
In any case if a device *needed* for a btrfs filesystem is missing, an error is
raised.
The patch enclosed allow to ignore the errors:
- ENXIO (device don''t exists)
- ENOMEDIUM (No medium found)
avoiding spurious messages during a scanning of the /dev directory.
I have to highlight that if a CDROM/DVD is inserted, the btrfs tools read the
cdrom, and this is a very slow operation.
Hugo, Chris,
please apply.
Anyway comments are welcome.
BR
P.S.
you can pull this patch from the following repository:
http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git
branch
skip-not-existent-devices
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