2.6.19.1 bug? tar: file changed as we read it

[Chuck Ebbert]

Trying to backup up a filesystem mounted via CIFS, I got these messages
from tar:

tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_CONNMARK.c: File shrank by 1178 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_TCPMSS.c: File shrank by 4177 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_DSCP.c: File shrank by 1172 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_tos.c: file changed as we read it
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_ECN.c: File shrank by 1638 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_mark.c: file changed as we read it
tar: t/2.6.10-orig/net/ipv6/netfilter/ip6t_mark.c: file changed as we read it

This was with kernel 2.6.19.1 SMP on x86_64, creating a tar file on a local
jfs filesystem (t is the source path on a cifs mount.)

Using 2.6.18.6-pre2 uniprocessor i386, with smbfs instead of cifs, everything
works fine so I'm pretty sure the server is OK.

Does this match any known problems?

[Avi Kivity]

Post by Chuck Ebbert
Trying to backup up a filesystem mounted via CIFS, I got these messages
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_CONNMARK.c: File shrank by 1178 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_TCPMSS.c: File shrank by 4177 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_DSCP.c: File shrank by 1172 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_tos.c: file changed as we read it
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_ECN.c: File shrank by 1638 bytes; padding with zeros
tar: t/2.6.10-orig/net/ipv4/netfilter/ipt_mark.c: file changed as we read it
tar: t/2.6.10-orig/net/ipv6/netfilter/ip6t_mark.c: file changed as we read it
This was with kernel 2.6.19.1 SMP on x86_64, creating a tar file on a local
jfs filesystem (t is the source path on a cifs mount.)
Using 2.6.18.6-pre2 uniprocessor i386, with smbfs instead of cifs, everything
works fine so I'm pretty sure the server is OK.
Does this match any known problems?

In 2.6.20-rc1, some of these files have other files with the same name
in the same directory (modulo case). Perhaps this is confusing cifs.

Can you check where all of the files in your case share that property?

example:

[***@firebolt linux-2.6]$ find net -iname ipt_tos.c
net/ipv4/netfilter/ipt_TOS.c
net/ipv4/netfilter/ipt_tos.c

[***@firebolt linux-2.6]$ find net -iname ipt_ecn.c
net/ipv4/netfilter/ipt_ECN.c
net/ipv4/netfilter/ipt_ecn.c

[Chuck Ebbert]

Post by Avi Kivity
In 2.6.20-rc1, some of these files have other files with the same name
in the same directory (modulo case). Perhaps this is confusing cifs.
Can you check where all of the files in your case share that property?
net/ipv4/netfilter/ipt_TOS.c
net/ipv4/netfilter/ipt_tos.c
net/ipv4/netfilter/ipt_ECN.c
net/ipv4/netfilter/ipt_ecn.c

Yes, that's it.

Using smbfs, both files have the same size and contents even though
they're really different:

$ ll ipt_dscp* ipt_DSCP*
-r--r----- 1 me me 2753 Jan 29 2004 ipt_dscp.c
-r--r----- 1 me me 2753 Jan 29 2004 ipt_DSCP.c
$ ll ipt_dscp.c ipt_DSCP.c
-r--r----- 1 me me 2753 Jan 29 2004 ipt_dscp.c
-r--r----- 1 me me 2753 Jan 29 2004 ipt_DSCP.c

With cifs, a directory search shows different sizes but opening
them by name gives identical contents:

$ ll ipt_dscp* ipt_DSCP*
-r-------- 1 me me 1581 Jan 28 2004 ipt_dscp.c
-r-------- 1 me me 2753 Jan 29 2004 ipt_DSCP.c
$ ll ipt_dscp.c ipt_DSCP.c
-r-------- 1 me me 1581 Jan 28 2004 ipt_dscp.c
-r-------- 1 me me 1581 Jan 28 2004 ipt_DSCP.c
$ diff ipt_dscp.c ipt_DSCP.c
$

So where is the bug? On the server?

[simo]

Post by Chuck Ebbert
With cifs, a directory search shows different sizes but opening
$ ll ipt_dscp* ipt_DSCP*
-r-------- 1 me me 1581 Jan 28 2004 ipt_dscp.c
-r-------- 1 me me 2753 Jan 29 2004 ipt_DSCP.c
$ ll ipt_dscp.c ipt_DSCP.c
-r-------- 1 me me 1581 Jan 28 2004 ipt_dscp.c
-r-------- 1 me me 1581 Jan 28 2004 ipt_DSCP.c
$ diff ipt_dscp.c ipt_DSCP.c
$
So where is the bug? On the server?

What is the server?
Samba? Which vertsion?
Do you use unix extensions? Or "case sensitive = yes" ?

Simo.
--
Simo Sorce
Samba Team GPL Compliance Officer
email: ***@samba.org
http://samba.org

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[Chuck Ebbert]

Post by simo

Post by Chuck Ebbert
With cifs, a directory search shows different sizes but opening
$ ll ipt_dscp* ipt_DSCP*
-r-------- 1 me me 1581 Jan 28 2004 ipt_dscp.c
-r-------- 1 me me 2753 Jan 29 2004 ipt_DSCP.c
$ ll ipt_dscp.c ipt_DSCP.c
-r-------- 1 me me 1581 Jan 28 2004 ipt_dscp.c
-r-------- 1 me me 1581 Jan 28 2004 ipt_DSCP.c
$ diff ipt_dscp.c ipt_DSCP.c
$
So where is the bug? On the server?

What is the server?
Samba? Which vertsion?

Samba 2.2.3.

Post by simo
Do you use unix extensions? Or "case sensitive = yes" ?

No UNIX extensions. Not case sensitive.

SO this is kind of expected, but smbfs and cifs client for Linux have
subtly different behavior.