[Qemu-devel] Severe data corruption in QEMU under Mac OS X

[Natalia Portillo]

10% of saved PPMs are corrupted or empty, hard disk images are  
randomly corrupted.

Tested under Mac OS X 10.6.1 (x86-64) and under Linux 2.6.31-gentoo-r1  
(x86-64) using QEMU 0.12.2 (manually compiled both)

No other program corrupts files (cp, Finder, Mail, TextEdit), neither  
they are corrupted when working on local hard disks.
There is no hardware error and testing have been done over an AFP  
share (shared by netatalk in the Linux test machine) as well as under  
local hard disk (Intel AHCI SATA)

When installing Nexenta OS Alpha 6 over the AFP share, the installer  
"ends" the copy at 5%, letting the QCOW2 image at 462 mebibytes, and  
restarting it shows corrupt on boot sector (GRUB unable to load).
When instaling in local hard disk, the installer ends at 100%, and the  
QCOW2 image is 1.7 gibibytes (1868300288 bytes). Bootloader is unable  
to find superblock.
When installing in Linux, using same QEMU command line and same  
installer choices (what should give the same QCOW2 image), the QCOW2  
image is 1.8 gibibytes (1919287296 bytes) and Nexenta boots correctly.

Using QCOW1 gives the same results.

zeus:QEMU claunia$ ls -l *.qcow2
-rw-r--r--  1 claunia  staff  1868300288 23 feb 20:21 Elatte Alpha  
6.qcow2

address@hidden /mnt/datos/Operating Systems/Incoming/feo/finished/ 
Elatte Alpha 6 $ ls -l *.qcow2
-rwxr-xr-x 1 claunia claunia 1919287296 feb 23 20:27 Elatte Alpha  
6.qcow2

zeus:Debian GNU-Hurd K10 claunia$ qemu -m 1024 -hda Debian\ GNU-Hurd\  
K10.qcow2 -monitor stdio -cdrom ../Debian\ GNU-Hurd\ K10\ \(DVD\).iso - 
net user -soundhw sb16 -vga cirrus -net nic,model=rtl8139
QEMU 0.12.2 monitor - type 'help' for more information
(qemu) screendump 1.ppm
(qemu) screendump 2.ppm
(qemu) screendump 3.ppm
(qemu) screendump 4.ppm
(qemu) screendump 5.ppm
(qemu) screendump 6.ppm
(qemu) screendump 7.ppm
(qemu) screendump 8.ppm
(qemu) screendump 9.ppm
(qemu) screendump 10.ppm
(qemu) screendump 11.ppm
(qemu) screendump 12.ppm
(qemu) screendump 13.ppm
(qemu) quit
zeus:Debian GNU-Hurd K10 claunia$ for i in *.ppm; do j=`basename  
"$i" .ppm`; convert -quality 90 "$i" "${j}.jpg"; done
convert: unable to read image data `11.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `11.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `9.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `9.jpg' @ convert.c/ 
ConvertImageCommand/2849.


zeus:Elatte Alpha 6 claunia$ qemu -m 1024 -hda Elatte\ Alpha\ 6.qcow2 - 
monitor stdio -cdrom Elatte\ Alpha\ 6.iso -net user -soundhw sb16 -vga  
cirrus -net nic,model=rtl8139
QEMU 0.12.2 monitor - type 'help' for more information
(qemu) screendump 1.ppm
(qemu) screendump 2.ppm
(qemu) screendump 3.ppm
(qemu) screendump 4.ppm
(qemu) screendump 5.ppm
(qemu) screendump 6.ppm
(qemu) screendump 7.ppm
(qemu) screendump 8.ppm
(qemu) screendump 9.ppm
(qemu) screendump 10.ppm
(qemu) screendump 11.ppm
(qemu) screendump 12.ppm
(qemu) screendump 13.ppm
(qemu) screendump 14.ppm
(qemu) screendump 15.ppm
(qemu) screendump 16.ppm
(qemu) screendump 17.ppm
(qemu) screendump 18.ppm
(qemu) screendump 19.ppm
(qemu) screendump 20.ppm
(qemu) screendump 21.ppm
(qemu) screendump 22.ppm
(qemu) screendump 23.ppm
(qemu) screendump 24.ppm
(qemu) screendump 25.ppm
(qemu) screendump 26.ppm
(qemu) screendump 27.ppm
(qemu) screendump 28.ppm
(qemu) quit
zeus:Elatte Alpha 6 claunia$ for i in *.ppm; do j=`basename  
"$i" .ppm`; convert -quality 90 "$i" "${j}.jpg"; done
convert: unable to read image data `15.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `15.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `19.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `19.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `20.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `20.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `21.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `21.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `27.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `27.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `28.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `28.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `3.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `3.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: improper image header `4.ppm' @ pnm.c/ReadPNMImage/298.
convert: missing an image filename `4.jpg' @ convert.c/ 
ConvertImageCommand/2849.
convert: unable to read image data `7.ppm' @ pnm.c/ReadPNMImage/924.
convert: missing an image filename `7.jpg' @ convert.c/ 
ConvertImageCommand/2849.