Re: [netfs/cifs - Linux 6.14] loop on file cat + file copy when files are on CIFS share

From: Nicolas Baranger
Date: Thu Apr 10 2025 - 04:44:50 EST


Hi Paulo

Thanks for answer and help

I'll look into it as soon as I recover from my illness.
Hope you're doing better

I had to rollback to linux 6.13.8 to be able to use the SMB share and here is what I constat
(don't know if it's a normal behavior but if yes, SMB seems to be a very very unefficient protocol)

I think the issue can be buffer related:
On Linux 6.13.8 the copy and cat of the 5 bytes 'toto' file containing only ascii string 'toto' is working fine but here is what I capture with tcpdump during transfert of toto file:
https://xba.soartist.net/t6.pcap
131 tcp packets to transfer a 5 byte file...
Isn't there a problem ?
Openning the pcap file with wireshark show a lot of lines:
25 0.005576 10.0.10.100 10.0.10.25 SMB2 1071 Read Response, Error: STATUS_END_OF_FILE
It seems that those lines appears after the 5 bytes 'toto' file had been transferred, and it continue until the last ACK recieved

I will try to reboot on Linux 6.14.0 mainline to see if I have the same behavior or to see what I get in the packet capture
(system is in production, I cannot reboot on a failing kernel when I want, it should be organised... sorry)

Let me know if you reproduced the issue

Kind regards
Nicolas Baranger



Le 2025-04-04 15:54, Paulo Alcantara a écrit :

Hi Nicolas,

I'll look into it as soon as I recover from my illness. Sorry for the delay.

On 4 April 2025 08:50:27 UTC, Nicolas Baranger <nicolas.baranger@xxxxxx> wrote: Hi Christoph

Thanks for answer and help
Did someone reproduced the issue (very easy) ?

CIFS SHARE is mounted as /mnt/fbx/FBX-24T
echo toto >/mnt/fbx/FBX-24T/toto

ls -l /mnt/fbx/FBX-24T/toto
-rw-rw-rw- 1 root root 5 20 mars 09:20 /mnt/fbx/FBX-24T/toto

cat /mnt/fbx/FBX-24T/toto
toto
toto
toto
toto
toto
toto
toto
^C

CIFS mount options:
grep cifs /proc/mounts
//10.0.10.100/FBX24T /mnt/fbx/FBX-24T cifs rw,nosuid,nodev,noexec,relatime,vers=3.1.1,cache=none,upcall_target=app,username=fbx,domain=HOMELAN,uid=0,noforceuid,gid=0,noforcegid,addr=10.0.10.100,file_mode=0666,dir_mode=0755,iocharset=utf8,soft,nounix,serverino,mapposix,mfsymlinks,reparse=nfs,nativesocket,symlink=mfsymlinks,rsize=65536,wsize=65536,bsize=16777216,retrans=1,echo_interval=60,actimeo=1,closetimeo=1 0 0

KERNEL: uname -a
Linux 14RV-SERVER.14rv.lan 6.14.0-rc2-amd64 #0 SMP PREEMPT_DYNAMIC Wed Feb 12 18:23:00 CET 2025 x86_64 GNU/Linux

Kind regards
Nicolas Baranger

Le 2025-03-28 11:45, Christoph Hellwig a écrit :

Hi Nicolas,

please wait a bit, many file system developers where at a conference
this week.