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Zucca
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Joined: 14 Jun 2007
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Location: Rasi, Finland
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 Posted: Fri Apr 24, 2020 8:35 am Post subject: autofs failing to mount sshfs - is autofs rotting? |
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| Code: | * net-fs/autofs
Latest version available: 5.1.6
Latest version installed: 5.1.5-r2
Size of files: 308 KiB
Homepage: https://web.archive.org/web/*/http://www.linux-consulting.com/Amd_AutoFS/autofs.html
Description: Kernel based automounter
License: GPL-2 |
... the homepage points to wayback machine.
The problem is that autofs passes -n -switch, which is not understood by fuse. There is already a bug raised for autofs, but with other than sshfs.
Are there alternatives for autofs for OpenRC based systems? I wouldn't want to start transitioning to systemd now... Besides I've always thought autofs is unnecessary complicated for a such simple tool that mounts filesystems on-demand.
If I were to implement such thing (for which I don't have proper skills, unfortunately), I'd probably would just have it read a single fstab like file (or file.d for a directory of several files). Timeouts defined in seperate columns or in -o options,umount_timeout=X -format.
And yes: I've also tried the latest version of autofs. I just tried to downgrade it to see if the problem exists with the older version too.
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szatox
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Joined: 27 Aug 2013
Posts: 3140
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| Posted: Fri Apr 24, 2020 11:29 am Post subject: |
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| Quote: | | Are there alternatives for autofs for OpenRC based systems? I wouldn't want to start transitioning to systemd now |
You can mount sshfs with /etc/fstab line. What feature does autofs provide you which requires this particular tool? I'm not familiar with it, although I do know it exists. |
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Ionen
Developer
Joined: 06 Dec 2018
Posts: 2720
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| Posted: Fri Apr 24, 2020 11:51 am Post subject: |
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| szatox wrote: | | You can mount sshfs with /etc/fstab line. What feature does autofs provide you which requires this particular tool? I'm not familiar with it, although I do know it exists. |
I don't use it but as far as I know it'd auto-mount when you attempt to access the directory rather than keep it always mounted (aka on-demand), which saves you from opening connections persistently for nothing, or need you to manually mount.
Rather than bother personally I do keep persistent mounts with /etc/fstab and openrc's netmount for sshfs (+some auto-reconnect settings so I can bring remote machine down/up and keep things mounted), but well, that's a different approach and I'm not familiar with autofs/alternatives.
Edit: although normal mount command should work if you have a proper /etc/fstab line and some automounter shouldn't need to call mount.fuse directly at all.. not that I know how it handles things |
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cz0
Apprentice
Joined: 13 Jun 2005
Posts: 280
Location: /earth/russia/moscow
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| Posted: Fri Apr 24, 2020 3:22 pm Post subject: |
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| szatox wrote: | | Quote: | | Are there alternatives for autofs for OpenRC based systems? I wouldn't want to start transitioning to systemd now |
You can mount sshfs with /etc/fstab line. What feature does autofs provide you which requires this particular tool? I'm not familiar with it, although I do know it exists. |
Not anymore.
| Code: |
host:/path/files /home/user/path fuse.sshfs noauto,user,nonempty,_netdev,idmap=user,default_permissions,uid=1000,gid=1000 0 0
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Fails now, while it used to work some time ago. |
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Ionen
Developer
Joined: 06 Dec 2018
Posts: 2720
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| Posted: Fri Apr 24, 2020 3:26 pm Post subject: |
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My sshfs lines in fstab looks like | Code: | user@host:/remote/dir /local/dir sshfs _netdev,ro,uid=myuser,gid=mygroup,allow_other,reconnect,idmap=user,transform_symlinks,\
ServerAliveInterval=15,ServerAliveCountMax=3,IdentityFile=/path/to/id_rsa,UserKnownHostsFile=/path/to/known_hosts 0 0 |
and work just fine. I can go and run "mount /local/dir" and it's mounted, or let openrc mount it without noauto since I normally never mount manually.
This is with fuse3, I did experience some breakage a while back when I moved away from fuse2 that needed me to update fstab.. but I was using ancient deprecated sshfs# syntax.
Edit: added full (broken in half) fstab line instead of cropping it, settings could probably be better.. haven't reviewed those in a while.
Last edited by Ionen on Fri Apr 24, 2020 4:23 pm; edited 1 time in total |
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Zucca
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Joined: 14 Jun 2007
Posts: 3347
Location: Rasi, Finland
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| Posted: Fri Apr 24, 2020 4:23 pm Post subject: |
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Yes. autofs is an on-demand mounter.
Need it because I have some devices (laptop, mobile phone) that are not always in the same network. I also have accees to a server where I keep few web pages etc where it's most effortless just to mount the files with sftp. I also push some backups there via rsync. But I surely don't want to keep the connection open all the time.
I have udisks on my system... I wonder if I could achieve same functionality with it via some tool?
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szatox
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Joined: 27 Aug 2013
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| Posted: Sat Apr 25, 2020 8:35 am Post subject: |
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Ok, so, how 'bout /etc/fstab line with additional options like user,noauto?
Depending on your DE you may be able to mount it transparently by entering that mountpoint.
Also, the simple trick with mount /path/to/mountpoint will work regardless of DE in use and does not require you remember all the options.
Is is there something else about autofs like checking for pre-conditions and mounting external resouces based on that instead of relaying on an invocation by the user? |
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Zucca
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Joined: 14 Jun 2007
Posts: 3347
Location: Rasi, Finland
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| Posted: Sun Apr 26, 2020 8:42 am Post subject: |
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| szatox wrote: | Ok, so, how 'bout /etc/fstab line with additional options like user,noauto?
Depending on your DE you may be able to mount it transparently by entering that mountpoint. |
If only that worked when cd'ing into the said directory.
I have all my photos on my server and my photo editors/manages need to be able to access the shares.
But yes, user,noauto is simple and I do like it.
Question: If I do that, can all the users mount these network filesystems? I assume not if the filesystem is in my home directory and permissions are set correctly.
I wonder if I could combine user,noauto mount and some inotify trick to make them automount without autofs... The tricky part would be to set some kind of timeout.
In the end I think OpenRC needs a on-demand-netmount service (as a subproject). ;)
| szatox wrote: | | Is is there something else about autofs like checking for pre-conditions and mounting external resouces based on that instead of relaying on an invocation by the user? |
Not that I know of. I think autofs only mounts the fs if any program tries to access it. Although autofs has tons of options in the config file...
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szatox
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Joined: 27 Aug 2013
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| Posted: Sun Apr 26, 2020 7:38 pm Post subject: |
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| Quote: | | Question: If I do that, can all the users mount these network filesystems? I assume not if the filesystem is in my home directory and permissions are set correctly. |
I think that you need write permission on the mountpoint to be able to mount it.
| Quote: | | If only that worked when cd'ing into the said directory. |
This is a tricky one.
You can track file_open event with inotify, but I think you will enter the directory first and THEN mount your network share on top of that. Which means you will see the contents of the underlying directory rather than then your network share, until you "cd ." |
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sveyret
n00b
Joined: 27 Oct 2016
Posts: 24
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| Posted: Wed Apr 29, 2020 7:47 am Post subject: |
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| Zucca wrote: | | If only that worked when cd'ing into the said directory. |
Maybe you could be interested in a tool I made a few years ago: https://github.com/sveyret/magicd/
There is no entry for an automount, but this should be rather easy to create. If you want to use it and need some help, do not hesitate and ask me.
(Note that there is an ebuild for it in my overlay: https://github.com/sveyret/sveyret-overlay)
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Gentoo in the Alps… |
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szatox
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| Posted: Fri May 08, 2020 9:27 am Post subject: |
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Actually, if you only need it for text console, you can use an alias that would check if there is anything to mount, mount it, and then cd into that directory. Seems easy enough to do.
Obviously, providing this functionality for other programs wouldn't be that easy. Chances are it would require patching some libs (libc?) to let you hijach a system call to open a file. And running this test for every single file open could really slow down your system. |
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Logicien
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Joined: 16 Sep 2005
Posts: 1555
Location: Montréal
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| Posted: Fri May 08, 2020 12:14 pm Post subject: |
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I use autofs since many years on different Linux distributions. What I do is to comment all the lines in /etc/autofs/auto.master and only give the path to a subdirectory file where all the mount points are defines with all options
| Code: | | /- /etc/autofs/auto.autofs |
In the /etc/autofs/auto.autofs file I have many lines to automount the root directory of Linux on other machine of my local wireless network. I automount my cdrom cd in there too
| Code: | /media/asus -fstype=cifs,_netdev,nofail,noserverino,password=,port=445,ro,vers=3.0 ://ASUS/Racine
/media/cdrom -fstype=auto,nodev,noexec,nofail,nosuid,ro :/dev/sr0 |
There is two files to configure, one is /etc/default/autofs in which there is only one none commented line who ask if I want to use misc device what I set to no
| Code: | | USE_MISC_DEVICE="no" |
The other one is /etc/autofs/autofs.conf. I give the uncommented lines that I use
| Code: | [ autofs ]
master_map_name = auto.master
timeout = 30
master_wait = 10
negative_timeout = 10
mount_verbose = no
mount_wait = 10
umount_wait = 10
browse_mode = yes |
As you can see the timeout to automount and autounmount are set there so I do not have to pass those options somewhere else. The two configure files can be somewhere else depending on the distribution. So, if you configure the subdirectory file (/etc/autofs/auto.autofs here) well with precise options, is mount will use none desires options? You have to check.
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Zucca
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Joined: 14 Jun 2007
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Location: Rasi, Finland
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| Posted: Fri May 15, 2020 10:53 am Post subject: |
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@Logicien: I've been using almost the exact same configuration as you from the beginning. The problem is autofs (or rather automount) passing the -n switch to fuse mounts. I think the problem started when I updated kernel... which is strange.
Also /etc/default/autofs is absent on my system. (Why the hell some programs do put their configuration there anyways? It seems to me like having another etc under /etc.)
I do have /etc/conf.d/autofs, from where I can try to solve this problem.
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shredator
Tux's lil' helper
Joined: 14 Apr 2005
Posts: 82
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| Posted: Sun Oct 24, 2021 3:33 am Post subject: |
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I'm having this same problem too. Anyone figure out how to have mount not pass the -n?
Also, I see that it is passing the -n because /etc/mtab is a link and not a file. If I delete the mtab link and just copy /proc/self/mounts to /etc/mtab, things work fine. But that only works until the next reboot.
I dont really know what all relies on mtab... would there be major breakage by changing the mtab init script to just copy instead of link? |
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Hu
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Posts: 21644
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| Posted: Sun Oct 24, 2021 4:36 am Post subject: |
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/etc/mtab is normally a link to /proc/self/mounts because that is the only way to keep it accurate in the general case. With mount namespaces, different processes can have different ideas of what is currently mounted, but they would by default share the same /etc/mtab.
Based on reading the autofs source, it automatically enables -n when /etc/mtab is a symlink to /proc/mounts or /proc/self/mounts. Presumably this means that if the link pointed to /proc/self/../mounts, then autofs would not enable passing -n. However, omitting -n may break for mounting filesystems that otherwise update mtab. I think you would be better served either fixing FUSE to accept -n, or changing autofs to have a specific option that inhibits -n, so that you can suppress it on a per-mount basis. |
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