You have been subscribed to a public bug:
I think I've found a bug or regression in something when trying to mount
a remote samba share. Modified/Created times are not properly preserved
in newer versions of Ubuntu. Because of this, rsync thinks files are
different based on their modified times and keeps re-syncing them.
I have a NAS on my network, running samba.
I have two devices, a desktop and laptop. Both are running Ubuntu, and
set up the exact same way. The desktop is running ubuntu 20.04, the
laptop 22.04.
I have mounted the NAS on both devices the exact same way. I attempt to
copy a file (rsync) the exact same way. On the 20.04 desktop, this works
perfectly fine. On the 22.04 laptop, the modified times are not
preserved and set to the current time, preventing things like rsync -t
from working.
The only difference i can find is that between the two systems, the newer
laptop 22.04 mount adds a few more options than the older system to the cifs
mount options. These are added automatically without being specified explicitly
(see the mount -v output below):
* 'forceuid'/'forcegid' are changed to 'noforceuid'/'noforcegid
* iocharset=utf8 added
* serverino added
desktop:
$ lsb_release -rd
Description:Ubuntu 20.04.5 LTS
Release:20.04
$ apt-cache policy cifs-utils
cifs-utils:
Installed: 2:6.9-1ubuntu0.2
Candidate: 2:6.9-1ubuntu0.2
Version table:
*** 2:6.9-1ubuntu0.2 500
500 http://us.archive.ubuntu.com/ubuntu focal-updates/main amd64
Packages
500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
100 /var/lib/dpkg/status
2:6.9-1 500
500 http://us.archive.ubuntu.com/ubuntu focal/main amd64 Packages
$ uname -a
Linux desktop 5.4.0-132-generic #148-Ubuntu SMP Mon Oct 17 16:02:06 UTC 2022
x86_64 x86_64 x86_64 GNU/Linux
$ mount -v
//nas/backup on /media/scratch type cifs
(rw,relatime,vers=3.0,cache=strict,username=nas_rw,uid=1000,forceuid,gid=1000,forcegid,addr=192.168.1.10,file_mode=0664,dir_mode=0775,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=60,actimeo=1)
laptop:
$ lsb_release -rd
Description:KDE neon 5.26
Release:22.04
$ apt-cache policy cifs-utils
cifs-utils:
Installed: 2:6.14-1ubuntu0.1
Candidate: 2:6.14-1ubuntu0.1
Version table:
*** 2:6.14-1ubuntu0.1 500
500 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages
500 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages
100 /var/lib/dpkg/status
2:6.14-1build1 500
500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages
$ uname -a
Linux laptop 5.15.0-60-generic #66-Ubuntu SMP Fri Jan 20 14:29:49 UTC 2023
x86_64 x86_64 x86_64 GNU/Linux
$ mount -v
//nas/backup on /media/scratch type cifs
(rw,relatime,vers=3.0,cache=strict,username=nas_rw,uid=1000,noforceuid,gid=1000,noforcegid,addr=192.168.1.10,file_mode=0664,dir_mode=0775,iocharset=utf8,soft,nounix,serverino,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=60,actimeo=1)
the remote NAS is a synology appliance, running Samba version 4.10.18.
SMB version 3
Steps to reproduce:
1. Similar setup, 1 device running 20.04, another running 22.04, otherwise up
to date.
2. mount the NAS on both devices the exact same way
$ sudo mount -t cifs -o
vers=3.0,credentials=/etc/samba/smbcreds,iocharset=utf8,rw,uid=1000,gid=1000,dir_mode=0775,file_mode=0664
//nas/backup /media/scratch
3. on the 20.04 older desktop, create a test file and show the modify time
$ fallocate -l 1M test1.txt
$ stat test1.txt
File: test1.txt
Size: 1048576 Blocks: 2048 IO Block: 4096 regular file
Device: 801h/2049d Inode: 13634663Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/desktop_user) Gid: ( 1000/desktop_user)
Access: 2023-02-12 18:35:48.978743377 -0700
Modify: 2023-02-12 18:35:48.978743377 -0700
Change: 2023-02-12 18:35:48.978743377 -0700
Birth: -
4. rsync the test file to the mount, stat the file and see the modify/change
are preserved
$ rsync -avh test1.txt /media/scratch/
sending incremental file list
test1.txt
sent 1.05M bytes received 35 bytes 2.10M bytes/sec
total size is 1.05M speedup is 1.00
$ stat /media/scratch/test1.txt
File: /media/scratch/test1.txt
Size: 1048576 Blocks: 2064 IO Block: 1048576 regular file
Device: 52h/82d Inode: 321811 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/desktop_user) Gid: ( 1000/desktop_user)
Access: 2023-02-12 18:38:25.671230900 -0700
Modify: 2023-02-12 18:35:48.978743300 -0700
Change: 2023-02-12 18:35:48.978743300 -0700
Birth: -
5. rsync again, notice the file is correctly skipped.
$ rsync -avh test1.txt /media/scratch/
sending incremental file list
sent 68 bytes received 12 bytes 160.00 bytes/sec
total size is 1.05M speedup is 13,107.20
6. repeat the same steps above on the newer 22.04 laptop, only this time notice
that the modify/change are NOT preserved. rsync re-sends the file because
