I am configuring vsftpd to allow anonymous user to upload files:
I enabled all below parameters
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anonymous_enable=YES
local_enable=YES
write_enable=YES
local_umask=022
anon_umask=077
anon_upload_enable=YES
anon_mkdir_write_enable=YES

log_ftp_protocol=YES
vsftpd_log_file=/var/log/vsftpd.log
anon_root=/var/ftp/pub
dual_log_enable=YES
syslog_enable=YES
---------------------------------------------

the directories setting:
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ls -l /var/ftp/
total 4
drwxr-xr-x 3 root root 4096 Nov 7 16:22 pub

ls -l /var/ftp/pub/
total 4
drwxr-xr-x 2 root root 4096 Nov 7 16:22 incoming

---------------------------------------------

when I tried upload file to directory incoming:

ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
drwxr-xr-x 2 0 0 4096 Nov 07 08:22 incoming
226 Directory send OK.
ftp> cd incoming
250 Directory successfully changed.
ftp> put /root/tmp.txt
local: /root/tmp.txt remote: /root/tmp.txt
200 PORT command successful. Consider using PASV.
553 Could not create file.
ftp>

Could someone help to point out what is wrong with my setting?
I also tried to enable vsftpd log, it is supposed to be at /var/log/vsftpd.log
but i can't find this file.

mistake
i should use put tmp.txt instead of using put /root/tmp.txt.

after using put tmp.txt
it works

ftp> put tmp.txt
local: tmp.txt remote: tmp.txt
200 PORT command successful. Consider using PASV.
150 Ok to send data.
226 Transfer complete.
5069 bytes sent in 0.0364 secs (139.30 Kbytes/sec)

ftp> ls -l
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
drwxrwxrwx 2 0 0 4096 Nov 07 09:05 incoming
226 Directory send OK.
ftp> cd incoming
250 Directory successfully changed.
ftp> ls -l
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
-rw-rw-rw- 1 14 50 5069 Nov 07 09:05 tmp.txt
226 Directory send OK.
ftp> put tmp.txt
local: tmp.txt remote: tmp.txt
200 PORT command successful. Consider using PASV.
553 Could not create file.

2nd question:
why can't I override tmp.txt?
from the parent directory and the file directory, the permission seem to OK.
Could someone help to point out my mistake?