[linux-cifs-client] Error while copying data from CIFS share

[Marko Käning]

Hi,

this is once again about my problems with error messages like this (was 
thread with subject "(no subject)" before):

---
Unusual System Events
=-=-=-=-=-=-=-=-=-=-=
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response to cmd 46 mid 47778
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: Send error in read = -11
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response to cmd 46 mid 47777
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: Send error in read = -11
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response to cmd 46 mid 47776
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: Send error in read = -11
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response to cmd 4 mid 47779
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: Send error in Close = -11
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response to cmd 46 mid 47780
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: Send error in read = -11
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response for cmd 50 mid 47783
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response for cmd 50 mid 47782
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: No response for cmd 50 mid 47781
Jul 28 23:28:17 flmpc35 kernel:  CIFS VFS: Send error in read = -9
---

Difference to before is this time that one of my 40000 backed-up files 
turned out to be different from its original, as my backup scripts told 
me:

---
kaening at flmpc35:~> LANG=C diff /backup/unpack/svnrepos/2005-2008/db/revs/1124 /home/svnrepos/2005-2008/db/revs/1124
Files /backup/unpack/svnrepos/2005-2008/db/revs/1124 and 
/home/svnrepos/2005-2008/db/revs/1124 differ
kaening at flmpc35:~>
---

and indeed, the retrieved file is actually shorter than the original:

---
kaening at flmpc35:~> ls -l /backup/unpack/svnrepos/2005-2008/db/revs/1124 /home/svnrepos/2005-2008/db/revs/1124
-rw-rw-r-- 1 root svncvs1 23850000  1. Jul 11:09 /backup/unpack/svnrepos/2005-2008/db/revs/1124
-rw-rw-r-- 1 root svncvs1 23853313  1. Jul 11:09 /home/svnrepos/2005-2008/db/revs/1124
kaening at flmpc35:~>
---

23850000 is quite characteristic, isn't it?

Well, the original in /home is of course of correct length. Turns out that 
the CIFS share on /backup-remote is also of correct length when I unpack 
it:

---
kaening at flmpc35:~/temp/bz> cp /backup-remote/backups/flmpc35/2008.07.28_21.01.47/svnrepos/2005-2008/db/revs/1124.bz2 .
kaening at flmpc35:~/temp/bz> bunzip2 1124.bz2
kaening at flmpc35:~/temp/bz> l
insgesamt 23332
drwxr-xr-x  2 kaening users     4096 29. Jul 10:42 ./
drwxr-xr-x 13 kaening users     4096 29. Jul 10:21 ../
-rw-r--r--  1 kaening users 23853313 29. Jul 10:42 1124
kaening at flmpc35:~/temp/bz>
---

so only the read failed during verification of my backup. I could not find 
any signs of failure in my logs while storeBackup was retrieving the 
faulty file from the CIFS share. Very odd! I'd have expected that there 
would be an error message when the file could not be transferred to the 
unpack directory. But there was none. If the error occurred just during 
the bunzip2 stage I'd have expected an error from bunzip2 popping up. But 
nothing like this happened...

This is the first time that a file wasn't properly restored after about a 
dozen of backup-verifications... Odd!


I just issued "echo 1 > /proc/fs/cifs/cifsFYI" and hope that the error is 
going to occur some time soon again so that I can give more information 
from my kernel's log.

Meanwhile I hope that some of you might come up with an idea.

Regards,
Marko