Stefan Hegnauer wrote:
On Monday, December 09, 2013 at 5:43 AM Konstantin Belousov wrote:

On Sun, Dec 08, 2013 at 06:31:36PM +0100, Stefan Hegnauer wrote:

I am using freebsd-current (FreeBSD BUILDMASTER 11.0-CURRENT FreeBSD
11.0-CURRENT #0 r259095: Sun Dec  8 10:20:40 CET 2013
root@BUILDMASTER:/usr/obj/usr/src/sys/ASUS  i386) in a VirtualBox as
a build
machine for nanobsd images to be used on alix boards.
The only
difference to GENERIC is the inclusion of 'march=geode' and disabling
most debugging switches (malloc, Witness etc). Worked like a charm in

Since late summer - sorry, no exact date / svn revision -
at the last stage when building the disk image, e.g. with


00:00:25 ### log: /usr/obj/nanobsd.alixpf//_.di


Looking a bit closer it seems that dd(1) returns with an I/O error
the input is a file created with mdconfig(8):

# dd if=/dev/zero of=somebackingfile bs=1k count=5k

# mdconfig -f somebackingfile -u md0

# newfs -U /dev/md0

# dd if=/dev/md0 of=/dev/null

dd: /dev/md0: Input/output error

10241+0 records in

10241+0 records out

5243392 bytes transferred in 3.240345 secs (1618159 bytes/sec)

The outputfile in seems to be error-free.
It should be one block larger than the right size.
Anyone else seen similar behaviour? How to proceed/fix it?

The following patch should clear the error.

The issue is that kern_physio() incorrectly detects EOF due to
calculation of bio bio_resid after the bio_length was clipped by the
'excess' code in g_io_check(). Both bio_length and bio_resid appear
to be 0 in the pre-last dd transfer, which starts exactly and the
mediasize, and kern_physio() thinks that it transferred one more block
than was transferred.

I _suspect_ that it was caused by 'excess' code moving in r256880,
but I am really not in the right condition to analyze it.  If somebody
could try the same dd experiment to confirm or deny my suspicion, it
would be useful.

The patch below should be a right thing to do anyway.

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index c23a74b..b7c4d60 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -3679,7 +3679,6 @@ bufdonebio(struct bio *bip)

        bp = bip->bio_caller2;
        bp->b_resid = bp->b_bcount - bip->bio_completed;
-       bp->b_resid = bip->bio_resid;     /* XXX: remove */
        bp->b_ioflags = bip->bio_flags;
        bp->b_error = bip->bio_error;
        if (bp->b_error)
Works for me - please commit!
Thanks a lot!


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I have a similar problem with on FreeBSD 10.x. I am able to build the image but sometimes (could not figured out the reason why) the image is build incorrectly.

For example on an incorrectly built image when I boot i got:

Trying to mount root from ufs:/dev/ada0s1a [ro]...
mount: /dev/ada0s3: Invalid argument
mount -o ro /dev/ada0s3 /conf/default/etc failed: dropping into /bin/sh

It seems the partition that hold config files cannot be accessed.

Hope your fix will fix this problem too (asumming you will also commit on 10.x).

Theres also an issue with package management, the nanobsd script still uses pkg_add instead of pkg.


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