Hello All,
Copied files to a SMB2 share, with `# cp -p`, do not retain the mtime
of the source file.
Copying the same file when the share is mounted as a SMBv1.0 share
does retain the mtime of the source file
This is trivial to reproduce and happens when the SMB server is Samba
or a Windows SMB server.
What I have yet to find is if this is a known protocol implementation
issue and/or if Samba is just copying Windows behavior.
I am emailing the list to see if anyone knows if this is a protocol
issue, but if anyone knows if the Samba behavior is just copying
Windows behavior that would be good to known.
Below are my reproducer steps and a short analysis.
Thanks for any input,
Jacob,
### Reproducer steps
# uname -r
5.0.0-0.rc2.git2.1.fc30.x86_64
# tcpdump -s0 -n -i ens3 -w /root/cp_p-testing-$(uname -r).pcap &
# mount //win2k16-dfs2.example.net/greendale /mnt/greendale -o sec=krb5,vers=2.1
# grep greendale /proc/mounts
//win2k16-dfs2.example.net/greendale /mnt/greendale cifs
rw,relatime,vers=2.1,sec=krb5,cache=strict,username=root,uid=0,noforceuid,gid=0,noforcegid,addr=192.168.124.133,file_mode=0755,dir_mode=0755,soft,nounix,serverino,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1
0 0
# touch test_file-{empty,data}
# echo 'hello world' >> test_file-data
# touch -d "2018-10-31" test_file*
# stat test_file*
File: test_file-data
Size: 12 Blocks: 8 IO Block: 4096 regular file
Device: fc04h/64516d Inode: 8410181 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Context: unconfined_u:object_r:admin_home_t:s0
Access: 2018-10-31 00:00:00.000000000 -0400
Modify: 2018-10-31 00:00:00.000000000 -0400
Change: 2019-01-22 10:48:04.027169240 -0500
Birth: -
File: test_file-empty
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fc04h/64516d Inode: 8409328 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Context: unconfined_u:object_r:admin_home_t:s0
Access: 2018-10-31 00:00:00.000000000 -0400
Modify: 2018-10-31 00:00:00.000000000 -0400
Change: 2019-01-22 10:48:04.027169240 -0500
Birth: -
# strace -fvttTyyx -s 4096 -o /root/cp_p-test_file-empty-$(uname
-r)-smb2.strace cp -p test_file-empty /mnt/greendale/test_file-empty
# date ; stat /mnt/greendale/test_file-empty
Tue 22 Jan 2019 10:48:46 AM EST
File: /mnt/greendale/test_file-empty
Size: 0 Blocks: 0 IO Block: 16384 regular empty file
Device: 2fh/47d Inode: 6755399441164937 Links: 1
Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Context: system_u:object_r:cifs_t:s0
Access: 2018-10-31 00:00:00.000000000 -0400
Modify: 2018-10-31 00:00:00.000000000 -0400
Change: 2019-01-22 10:48:40.085169200 -0500
Birth: -
# strace -fvttTyyx -s 4096 -o /root/cp_p-test_file-data-$(uname
-r)-smb2.strace cp -p test_file-data /mnt/greendale/test_file-data
# date ; stat /mnt/greendale/test_file-data
Tue 22 Jan 2019 10:49:09 AM EST
File: /mnt/greendale/test_file-data
Size: 12 Blocks: 1 IO Block: 16384 regular file
Device: 2fh/47d Inode: 4222124650769034 Links: 1
Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Context: system_u:object_r:cifs_t:s0
Access: 2019-01-22 10:48:45.245674900 -0500
Modify: 2019-01-22 10:48:45.245674900 -0500
Change: 2019-01-22 10:48:45.245674900 -0500
Birth: -
# rm -f /mnt/greendale/test_file*
# umount /mnt/greendale
# mount //win2k16-dfs2.example.net/greendale /mnt/greendale -o sec=krb5,vers=1.0
# strace -fvttTyyx -s 4096 -o /root/cp_p-test_file-data-$(uname
-r)-smb.strace cp -p test_file-data /mnt/greendale/test_file-data
# date ; stat /mnt/greendale/test_file-data
Tue 22 Jan 2019 10:50:08 AM EST
File: /mnt/greendale/test_file-data
Size: 12 Blocks: 1 IO Block: 16384 regular file
Device: 2fh/47d Inode: 7036874417875593 Links: 1
Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Context: system_u:object_r:cifs_t:s0
Access: 2018-10-31 00:00:00.000000000 -0400
Modify: 2018-10-31 00:00:00.000000000 -0400
Change: 2019-01-22 10:50:02.926169200 -0500
Birth: -
# pkill tcpdump
### SMB2
o Nanosecond timestamps being set
$ grep utimensat *smb2.strace
cp_p-test_file-data-5.0.0-0.rc2.git2.1.fc30.x86_64-smb2.strace:826
10:49:02.689258 utimensat(4</mnt/greendale/test_file-data>, NULL,
[{tv_sec=1540958400, tv_nsec=0} /* 2018-10-31T00:00:00-0400 */,
{tv_sec=1540958400, tv_nsec=0} /* 2018-10-31T00:00:00-0400 */], 0) = 0
<0.007301>
cp_p-test_file-empty-5.0.0-0.rc2.git2.1.fc30.x86_64-smb2.strace:818
10:48:40.086403 utimensat(4</mnt/greendale/test_file-empty>, NULL,
[{tv_sec=1540958400, tv_nsec=0} /* 2018-10-31T00:00:00-0400 */,
{tv_sec=1540958400, tv_nsec=0} /* 2018-10-31T00:00:00-0400 */], 0) = 0
<0.001168>
o Attributes being sent over the network.
$ tshark -n -r cp_p-testing-5.0.0-0.rc2.git2.1.fc30.x86_64.pcap -Y
'smb2.cmd==setinfo && smb2.flags.response == 0' -T fields -e
frame.number -e smb2.last_write.time -e smb2.last_access.time -e
smb2.last_change.time -e smb2.msg_id -e smb2.filename -E header=y | tr
'\t' '#' | column -t -s '#'
frame.number smb2.last_write.time
smb2.last_access.time smb2.last_change.time
smb2.msg_id smb2.filename
285 Oct 31, 2018 00:00:00.000000000 EDT Oct 31, 2018
00:00:00.000000000 EDT Jan 22, 2019 10:48:40.085169200 EST 21,22,23
test_file-empty
392 Oct 31, 2018 00:00:00.000000000 EDT Oct 31, 2018
00:00:00.000000000 EDT Jan 22, 2019 10:49:02.688169200 EST 34,35,36
test_file-data
o The server returns a 0 status.
$ tshark -n -r cp_p-testing-5.0.0-0.rc2.git2.1.fc30.x86_64.pcap -Y
'smb2.cmd==setinfo && smb2.flags.response == 1' -T fields -e
frame.number -e smb2.nt_status -e smb2.msg_id -E header=y | tr '\t'
'#' | column -t -s '#'
frame.number smb2.nt_status smb2.msg_id
286 0,0,0 21,22,23
393 0,0,0 34,35,36
o For the empty file, mtime is not mtime is not modified.
$ tshark -n -r cp_p-testing-5.0.0-0.rc2.git2.1.fc30.x86_64.pcap -Y
'smb2.cmd==getinfo && smb2.flags.response == 1 && frame.time >
"2019-01-22 10:48:46" && frame.time < "2019-01-22 10:48:47"' -T fields
-e frame.number -e smb2.last_write.time -e smb2.last_access.time -E
header=y | tr '\t' '-' | column -t -s '-'
frame.number smb2.last_write.time
smb2.last_access.time
315 Oct 31, 2018 00:00:00.000000000 EDT,Oct 31, 2018
00:00:00.000000000 EDT,Dec 31, 1969 19:00:00.000000000 EST Oct 31,
2018 00:00:00.000000000 EDT,Oct 31, 2018 00:00:00.000000000 EDT,Dec
31, 1969 19:00:00.000000000 EST
o For the non-empty file, mtime is modified despite being set after
the WRITE completed.
$ tshark -n -r cp_p-testing-5.0.0-0.rc2.git2.1.fc30.x86_64.pcap -Y
'smb2.cmd==getinfo && smb2.flags.response == 1 && frame.time >
"2019-01-22 10:49:09" && frame.time < "2019-01-22 10:49:10"' -T fields
-e frame.number -e smb2.last_write.time -e smb2.last_access.time -E
header=y | tr '\t' '-' | column -t -s '-'
frame.number smb2.last_write.time
smb2.last_access.time
421 Jan 22, 2019 10:48:45.245674900 EST,Jan 22, 2019
10:48:45.245674900 EST,Dec 31, 1969 19:00:00.000000000 EST Oct 31,
2018 00:00:00.000000000 EDT,Oct 31, 2018 00:00:00.000000000 EDT,Dec
31, 1969 19:00:00.000000000 EST
### SMB
o Nanosecond timestamps being set
$ grep utimensat *smb.strace
842 10:50:02.926848 utimensat(4</mnt/greendale/test_file-data>,
NULL, [{tv_sec=1548172142, tv_nsec=687169240} /*
2019-01-22T10:49:02.687169240-0500 */, {tv_sec=1540958400, tv_nsec=0}
/* 2018-10-31T00:00:00-0400 */], 0) = 0 <0.001564>
o Attributes being sent over the network.
o The server returns a 0 status.
$ tshark -n -r cp_p-testing-5.0.0-0.rc2.git2.1.fc30.x86_64.pcap -Y
'smb.trans2.cmd == 8' -T fields -e frame.number -e smb.last_write.time
-e smb.access.time -e smb.mid -e smb.nt_status -E header=y | tr '\t'
'#' | column -t -s '#'
frame.number smb.last_write.time smb.access.time
smb.mid smb.nt_status
628 Oct 31, 2018 00:00:00.000000000 EDT Jan 22, 2019
10:49:02.687169200 EST 17 0
629
17 0
630 Dec 31, 1969 19:00:00.000000000 EST Dec 31, 1969
19:00:00.000000000 EST 18 0
631
18 0
o When using SMBv1.0, mtime is respected.
$ tshark -n -r cp_p-testing-5.0.0-0.rc2.git2.1.fc30.x86_64.pcap -Y
'smb.trans2.cmd == 5 && frame.time >= "2019-01-22 10:50:08"' -T fields
-e frame.number -e smb.last_write.time -e smb.access.time -e smb.mid
-E header=y | tr '\t' '#' | column -t -s '#'
frame.number smb.last_write.time smb.access.time
smb.mid
657
20
658 Oct 31, 2018 00:00:00.000000000 EDT Jan 22, 2019
10:49:02.687169200 EST 20
