Bug 502365

Summary: RAMDISK: incomplete write (-28 != 32768) 16777216
Product: [Fedora] Fedora Reporter: Richard W.M. Jones <rjones>
Component: libguestfsAssignee: Richard W.M. Jones <rjones>
Status: CLOSED UPSTREAM QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: low    
Version: rawhideCC: rjones, virt-maint
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2009-05-24 14:42:46 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Richard W.M. Jones 2009-05-24 13:53:27 UTC 
Appliance fails to boot.  When you boot with LIBGUESTFS_DEBUG=1
you see messages such as:

RAMDISK: Compressed image found at block 0
RAMDISK: incomplete write (-28 != 32768) 16777216

RAMDISK: Compressed image found at block 0
RAMDISK: incomplete write (-28 != 32768) 40960000

(The precise numbers may be slightly different).
Comment 1 Richard W.M. Jones 2009-05-24 13:56:46 UTC 
This error only happens when we try to run libguestfs
on Debian (still using Fedora inside the appliance of
course).

We found by googling and experimentation that we can
get rid of the 'RAMDISK: incomplete write' error by adding
ramdisk=NNN option, eg:

LIBGUESTFS_APPEND="ramdisk_size=128000"

However this doesn't in itself resolve the problem with
booting.
Comment 2 Richard W.M. Jones 2009-05-24 13:57:48 UTC 
(In reply to comment #1)
> ramdisk=NNN option, eg:

That should be 'ramdisk_size=NNN' of course.
Comment 3 Richard W.M. Jones 2009-05-24 14:42:46 UTC 
False alarms all round - the ramdisk_size parameter is NOT needed.

The problem was that Debian's cpio command defaults to using
the obsolete 'bin' cpio format, not 'newc' (which is what Fedora
defaults to).  Therefore Debian's cpio was making an initramfs
image that the kernel simply couldn't understand.

Fixes to this are:
http://git.et.redhat.com/?p=febootstrap.git;a=commit;h=346a893d8035212e8d2acbe3a14521df504116e2
http://git.et.redhat.com/?p=febootstrap.git;a=commit;h=0eacd743cb1ff655a09f7b941320a0235d482df0