dns cifs share entry in fstab not re-mounted on IP change, while used by smbd

Flo

10/2/23, 8:36 AM

I set up a CIFS share on my ubuntu

Distributor ID: Ubuntu
Description:    Ubuntu 20.04 LTS
Release:        20.04

using an fstab entry:

//mystr.myserver.com/backup /mnt/mystr       cifs    iocharset=utf8,rw,_netdev,credentials=/etc/smb/mystr-credentials,uid=someuser,gid=0,file_mode=0660,dir_mode=0770 0       0

which works as expected.

now i do have smbd running to provide this share to users on my LAN with this section in /etc/samba/smb.conf

[mystr]
path = /mnt/mystr
public = yes
writeable = yes
browsable = yes
guest ok = yes
force user = someuser

which also works fine.

However there seems to be an issue if the IP address of the entry mystr.myserver.com changes. The share says "Host is down." and mount shows me the outdated IP address.

As this does not happen very often it is not easy to reproduce. This morning I wanted to fix it manually and tried to unmount it first which gave me Resource is busy as I think the smbd process is blocking the share.

Stopping the smbd process, unmounting the share, using mount -a and restarting smbd solved the issue.

So my questions are: Can this be done automatically? Can I tell fstab to force re-mounting the share if it is down? Is this even related to smbd having a handle on the directory? I checked lsof, but could not find anything related. Can I tell samba to "let go" of unreachable directories?

Thanks in advance for any ideas/Suggestions.

0 + 0

mount

cifs

fstab

Gerald Schneider

10/2/23, 8:39 AM

configure your server with a fixed IP.

Flo

10/2/23, 8:43 AM

@GeraldSchneider although ´mystr.myserver.com´ might indicate it is my server - i can not control the ip address of this domain.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: dns cifs share entry in fstab not re-mounted on IP change, while used by smbd

TH: dns cifs แบ่งปันรายการใน fstab ไม่ได้เมานต์ใหม่เมื่อเปลี่ยน IP ในขณะที่ใช้โดย smbd

RO: intrarea de partajare dns cifs în fstab nu a fost remontată la schimbarea IP, în timp ce este utilizată de smbd

RU: Запись совместного доступа dns cifs в fstab не перемонтируется при изменении IP, хотя используется smbd

VI: mục chia sẻ dns cifs trong fstab không được gắn lại khi thay đổi IP, trong khi được sử dụng bởi smbd

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