[Nbd] kernel errors when sharing DVD via nbd

[Kirill Belokurov <kirill.belokurov@...17...>]

Hi!

I am trying to share the DVD using nbd, but from time to time I am getting the 
following errors: nbd client connects successfuly to the server, but during 
read, the disk read errors appear. The DVD itself is OK, it is playable on 
server, copiable via 'dd', etc.

I tried to play the DVD in the other DVD drive and got the similar errors, 
there was only the name of DVD device that changed. This happens both for IDE 
and SCSI  DVD drives.

I would appreciate any advice on this. Thanks in advance.

The kernel on both client and server is:
2.6.20-16 , i686
NBD version is 2.8.7

I am quoting the syslog messages that appear on attempt to playback the DVD at 
client (using xine):

client-side:
Jul 18 11:32:14 moon kernel: nbd0: Other side returned error (-1)
Jul 18 11:32:14 moon kernel: end_request: I/O error, dev nbd0, sector 2416
Jul 18 11:32:14 moon kernel: Buffer I/O error on device nbd0, logical block 
1208
Jul 18 11:32:14 moon kernel: Buffer I/O error on device nbd0, logical block 
1209
Jul 18 11:32:14 moon kernel: Buffer I/O error on device nbd0, logical block 
1210
...


server-side:
Jul 18 11:32:09 sun nbd_server[25398]: connect from 192.168.80.2, assigned 
file is /dev/cdrom
Jul 18 11:32:09 sun nbd_server[25398]: Can't open authorization file (null) 
(Bad address).
Jul 18 11:32:09 sun nbd_server[25398]: Authorized client
Jul 18 11:32:09 sun nbd_server[10523]: Starting to serve
Jul 18 11:32:09 sun nbd_server[10523]: size of exported file/device is 
8208672768
Jul 18 11:32:13 sun kernel: [85920.508000] hdc: command error: status=0x51 { 
DriveReady SeekComplete Error }
Jul 18 11:32:13 sun kernel: [85920.508000] hdc: command error: error=0x54 { 
AbortedCommand LastFailedSense=0x05 }
Jul 18 11:32:13 sun kernel: [85920.508000] ide: failed opcode was: unknown
Jul 18 11:32:13 sun kernel: [85920.508000] hdc: error code: 0x70  sense_key: 
0x05  asc: 0x6f  ascq: 0x03
Jul 18 11:32:13 sun kernel: [85920.508000] end_request: I/O error, dev hdc, 
sector 2496
Jul 18 11:32:13 sun kernel: [85920.508000] Buffer I/O error on device hdc, 
logical block 624
Jul 18 11:32:13 sun kernel: [85920.508000] Buffer I/O error on device hdc, 
logical block 625
Jul 18 11:32:13 sun kernel: [85920.508000] Buffer I/O error on device hdc, 
logical block 626
...


Best regards, Kirill