file corruption copying from cifs mounted OS/2 share

[[e-mail]]

I recenty installed linux mint 13 maya - x64 edition on a multiboot system for testing. I recently found that files copied from a cifs mounted OS/2 share are corrupted in a particular pattern.

The first 4297 bytes are copied correctly, so any small files would not manifest the problem. The next 3895 bytes of the file are replaced with x'00' bytes. The next 12489 bytes are copied correctly, followed by another 3895 bytes of x'00' instead of the actual file contents. This pattern continues with 12489 bytes from the original file followed by 3895 x'00' bytes until the file size is reached.

The smbstatus command reports Samba version 3.6.3 is running in my copy of maya. I have tested this on my other two versions of mint that are running here and neither of them manifest this problem. One system is linux mint 11 katya - x64 edition, which reports Samba version 3.5.8 and the other is the current linux mint 8 helena - x64 edition on the same system I am testing maya on which reports Samba version 3.4.0 running.

An example fstab entry for one of the OS/2 shares to mount is:

//tp600e/HDRIVE /mnt/x_ cifs user=userid%password,servern=TP600E,sec=lanman,nocase,uid=1000,noserverino 0 0

I have attached a copy of a very simple testfile I used to demonstrate the problem and the corrupted results of a copy.

I will be happy to provide additional information to assist in diagnosing and correcting this problem. Until this issue is corrected I cannot deploy maya in place of older linux mint releases here.

[[e-mail] (dhdurgee)]

To confirm that the problem was a replacement of file content with x'00' bytes as opposed to insertion of x'00' bytes I constructed another test file that more clearly shows this behavior.

[[e-mail] (dhdurgee)]

I did a bit more research and found out about cifsFYI, traceSMB and DebugData in /proc/fs/cifs/ and set them to debug the operation in question on both helena and maya. The results are in the attached file, which show obvious differences in the SMB trace even to me. I don't know enough to determine if the problem is in cifs or samba, but I would think that someone with knowledge of the system and the source can use this data to do so. If more information is required I will be happy to provide it.

[[e-mail] (dhdurgee)]

I have done some additional testing to confirm this is not due to an installation error:

1) I booted a verified maya LiveDVD and was able to recreate the problem.

2) I booted a lisa LiveCD and the problem was not present.

From this I conclude that:

1) this is NOT an installation error, my maya install is indeed "working as designed"

2) this is a recent problem, as it is not present in lisa but is present in maya

[[e-mail] (dhdurgee)]

With the assistance of the samba people this bug has been isolated to recent changes in the cifs.ko that resulted in a change to the default rsize that caused problems with my older servers. This can be worked around by supplying appropriate rsize values in the fstab or on the mount command for the shares experiencing the problem. I am wating to test a patch that is expected to correct this problem in the future.

Dave