Strange rsync samba btrfs behavior by Files lesser than 26MB

Question

i have created a btrfs filesystem on my Raspberry Pi with a simple subvolume Data01, to share for backup my Server i've created a samba share on raspberry

After that i mounted the samba share on my ubuntu 20.04 Server by fstab and tried to rsync some files from server to raspi

At first look it works fine, but on a second sync it looked like rsync copies all Files again I've never used rsync before, so i added a large file (3.2GB ISO) to my folder on server and it would copy only once but smaller files would be copied everytime

So my next thing was to check on which file size rsync stopps to copy files everytime And it looks like 26MB

So after that i looked with stats and i could see that smaller Files dosen't have correct time values

 Datei: Zwergentrunk-1.pdf
  Gr▒▒e: 740838         Bl▒cke: 1448       EA Block: 4096   regul▒re Datei
Ger▒t: 2eh/46d  Inode: 4917        Verkn▒pfungen: 1
Zugriff: (0744/-rwxr--r--)  Uid: ( 1001/srvbackup)   Gid: ( 1001/srvbackup)
Zugriff    : 2022-04-06 21:16:26.471913500 +0200
Modifiziert: 2022-04-06 21:16:26.563488588 +0200
Ge▒ndert   : 2022-04-06 21:16:26.557414539 +0200
Geburt     : -

But Larger File

Datei: ubuntu-20.04.4-desktop-amd64.iso
  Gr▒▒e: 3379068928     Bl▒cke: 6599744    EA Block: 4096   regul▒re Datei
Ger▒t: 2eh/46d  Inode: 4911        Verkn▒pfungen: 1
Zugriff: (0744/-rwxr--r--)  Uid: ( 1001/srvbackup)   Gid: ( 1001/srvbackup)
Zugriff    : 2022-04-06 18:40:32.667789400 +0200
Modifiziert: 2022-03-20 23:29:45.304778200 +0100
Ge▒ndert   : 2022-04-06 18:40:36.193852990 +0200
Geburt     : -

I hope someone has any Idea, best regards

fstab on raspi (shortened)

UUID=1483d2ca-66f7-4fe4-9494-4802b078a30b       /mnt/Backup01   btrfs   defaults        0       1

smb.conf

[global]
   workgroup = ESD
   dns proxy = no
   log file = /var/log/samba/log.%m

   max log size = 1000
   syslog = 0
   panic action = /usr/share/samba/panic-action %d
   server role = standalone server
   passdb backend = tdbsam
   obey pam restrictions = yes
   unix password sync = yes

   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .

   pam password change = yes
   map to guest = bad user
   usershare allow guests = yes


[homes]
   comment = Home Directories
   browseable = no
   read only = yes
   create mask = 0700
   directory mask = 0700
   valid users = %S

[printers]
   comment = All Printers
   browseable = no
   path = /var/spool/samba
   printable = yes
   guest ok = no
   read only = yes
   create mask = 0700

[print$]
   comment = Printer Drivers
   path = /var/lib/samba/printers
   browseable = yes
   read only = yes
   guest ok = no

[Backup01-Data01]
        path= /mnt/Backup01/Data01
        browsable = yes
        read only false
        guest ok = no
        inherit acls = no
        inherit permissions = yes
        ea support = no
        store dos attributes = no
        printable = no
        #create mask = 0664
        #force create mode 0664
        #directory mask = 0775
        #force directory mode = 0775
        hide special files = yes
        follow symlinks = yes
        hide dot files = yes
        valid users = srvbackup
        invalid users =
        read list = srvbackup
        write list = srvbackup
        force user=srvbackup

fstab on server (shortened)

//officebeere/Backup01-Data01 /mnt/Backup01-Data01 cifs _netdev,uid=1000,gid=1000,username=srvbackup,password=**********  0  0

rsync command

sudo rsync -avit --no-p  --progress --delete Zwergentrunk/ /mnt/Backup01-Data01/

Update:

I've tested more and i'can say it's not an btrfs issue (tested with an other HDD and ext4 still same problem) It's not only with rsync, tried with cp -a or cp -preserver=timestamps --> same issue but with a small difference on copy i'can see the correct modify date first and then it will be changed

I tried from Windows with copy and paste --> Modify date is correct

But with touch -r sourefile destfile, i get correct dates, so a workaround would be possible

I hope someone has a better Solution, i think it's a Samba Server or Mount smb share issue

Mount says that's are my Mount options

//officebeere/Backup01-Data01 on /mnt/Backup01-Data01 type cifs (rw,relatime,vers=3.1.1,cache=strict,username=srvbackup,uid=1000,noforceuid,gid=1000,noforcegid,addr=192.168.1.5,file_mode=0755,dir_mode=0755,soft,nounix,serverino,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=60,actimeo=1,_netdev)

Answer 1

Ok i found it, it's an bug in Samba, so i checked the Version and upgrade to the newest Raspberry OS and it works now