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
--
gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreijack@xxxxxxxxx>
Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512commit 3635fcf3f7358f006a5025b9773034088bdd01fd
Author: Goffredo Baroncelli <kreijack@xxxxxxxxx>
Date: Fri Oct 21 19:00:28 2011 +0200
Ignore the error ENXIO and ENOMEDIUM during a devs scan
Ignore the error ENXIO (device don't exists) and ENOMEDIUM (
No medium found -> like a cd tray empty) in the function
btrfs_scan_one_dir.
This avoids spurios errors due to an empty CD or a block device node
without a device (which is frequent in a static /dev).
Signed-off-by: Goffredo Baroncelli <kreijack@xxxxxxxxx>
diff --git a/utils.c b/utils.c
index 86c643c..5761e47 100644
--- a/utils.c
+++ b/utils.c
@@ -997,8 +997,14 @@ again:
}
fd = open(fullpath, O_RDONLY);
if (fd < 0) {
- fprintf(stderr, "failed to read %s: %s\n", fullpath,
- strerror(errno));
+ /* ignore the following errors:
+ ENXIO (device don't exists)
+ ENOMEDIUM (No medium found ->
+ like a cd tray empty)
+ */
+ if(errno != ENXIO && errno != ENOMEDIUM)
+ fprintf(stderr, "failed to read %s: %s\n",
+ fullpath, strerror(errno));
continue;
}
ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
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