isWritable() for NFS directory

micdnj

Hi,

I'm using code below. /mnt/DS/ is mounted to remote resource with NFS ver. 3. I can create new files from command line in this directory. Everyone has rights to modify it. But isWriteble() returns False. Is it expected behavior? I have an app, which is unusable due to this.
I'm using Arch Linux with Qt 5.15 and connecting to Synology NAS.

from PyQt5.QtCore import QFileInfo

info = QFileInfo("/mnt/DS/Wideo")
print('isWritable: ' + str(info.isWritable()))

JonB

@micdnj
Check out what Python calls like os.access() and os.stat() have to say?

Check what QFile::Permissions QFileInfo::permissions() const has to say?

Check what QFileInfo("/mnt/DS/Wideo/somefileyouhavethere") has to say?

Verify you really can create /mnt/DS/Wideo/newfile from Qt, just to be sure.

/mnt/DS/Wideo

Your directory really is Wideo and not Video, else you wouldn't have posted this, right?!

What does ls -ld /mnt/DS/Wideo look like?

micdnj

First findings.

Current state
Directory:

$ ls -ld ../Wideo/
drwxrwxrwx 39 1026 100 4096 22 sty 14:53 ../Wideo/

With files:

.rwxrwxrwx    4 michal 22 sty 15:14 t.txt
.rwxrwxrwx    0 michal 22 sty 01:06 test.txt
.rwxrwxrwx 4,7G 1030   21 sty 23:28 The.Chorus.mkv

What is worth noting, that owner of The.Chorus.mkv (id=1030) and Wideo/ doesn't exists in local linux instalation, that's why user name isn't printed.

Python
Results are given in comments.

print(os.access("/mnt/DS/Wideo", os.W_OK)) #False
print(os.access("/mnt/DS/Wideo", os.R_OK)) #True

with open("/mnt/DS/Wideo/t.txt", 'w') as f: #File created
    f.write('test')
print(os.access("/mnt/DS/Wideo/t.txt", os.W_OK)) #True
print(os.access("/mnt/DS/Wideo/test.txt", os.W_OK)) #True
print(os.access("The.Chorus.mkv", os.W_OK)) #False
with open("The.Chorus.mkv", 'w') as f: #File opened to writing
    print('opened')

So, /mnt/DS/Wideo, and The.Chorus.mkv aren't(based on os.access()) writable, but I can create file in directory, and open file for changes.

System
on system level, command

test -w The.Chorus.mkv; echo "$?"

and also

res = os.system('test -w /mnt/DS/Wideo/The.Chorus.mkv')

show, that I have write permission.
But

test -w ../Wideo/; echo "$?"

shows no rights to write.

Your directory really is Wideo and not Video, else you wouldn't have posted this, right?!

Yes :) It's in polish.
Let me know if it's still necessary to make checks you've mentioned but I haven't done.

Kent-Dorfman

your problem is the uid mapping and/or mount options. that's why you can create files and edit files you create but otherwise cannot manage the directory. read the RFCs on NFS to determine the behaviour.