Setting the allow_other Option in a Config File

[dbq-andersons]

Hi Everyone,

Still pretty green at this stuff, but gcsfuse is solving a pretty big problem I was having, so happy it's around.

I have entries similar to these in an /etc/fstab file on a Google Cloud VM and they are working very well.

bucket-name /bucket/mount/point gcsfuse rw,_netdev,allow_other,uid=2000,gid=33,dir_mode=775,file_mode=664,only_dir=directory
bucket-name2 /bucket/mount/point2 gcsfuse rw,_netdev,allow_other,uid=2001,gid=33,dir_mode=775,file_mode=664,only_dir=directory

However, as I'm starting to look at dabbling in cache settings and whatnot, I'd like to move all common settings to an /etc/gcsfuse.yaml config file and call that from /etc/fstab with something like this:

bucket-name /bucket/mount/point gcsfuse _netdev,uid=2000,config_file=/etc/gcsfuse.yaml
bucket-name2 /bucket/mount/point2 gcsfuse _netdev,uid=2001,config_file=/etc/gcsfuse.yaml

Here's my config file (/etc/gcsfuse.yaml).

file-system:
  dir-mode: "775"
  file-mode: "664"
  gid: "33"
  fuse-options: rw,allow-other
only-dir: "directory"

Most of those configs work fine and are being picked up. However, the allow-other option is not being applied. Here's a snippet from the mount command output showing that the "rw" option is getting picked up and I have confirmed I can write to the file system as root.

"FileMode":"664","FuseOptions":["rw"],"Gid":33,

If I leave allow_other in the fstab line, here's the relevant area of that output.

"FileMode":"664","FuseOptions":["rw","allow_other"],"Gid":33,

Among a few other things, I have tried allow_other. I have also tried just dropping that setting raw in the .yaml file on a line by itself (IIRC, it wouldn't even mount then).

I could leave allow_other in the /etc/fstab lines, but it's vexing me as to why this won't work. I'm guessing I have something wrong with where I'm putting it or something similar, but I can't find anything in the docs to point me in the right direction.

Any ideas?

Bill

[dbq-andersons]

As I'm digging through this and trying different settings, I noticed something odd. If I remove the "rw" from fuse-options line in my .yaml file, that option still gets applied when mounted.

,"FileMode":"664","FuseOptions":["rw"],"Gid":33,

The "rw" isn't in my /etc/fstab line. Wondering where that's coming from...is it the default?

[Tulsishah]

@dbq-andersons, the default file system access is "rw" (read-write) unless you have defined a specific access type (e.g., "ro" for read-only). ref

I tested your configuration file as defined in comment#1 and found that I needed to update allow-other to allow_other. After making this change, when I mounted GCSFuse using your configuration file, it appeared to work correctly. I was able to see the allow_other option in fusermount.

bucket on /usr/local/google/home/tulsishah/gcs type fuse.gcsfuse (rw,nosuid,nodev,relatime,user_id=1052824,group_id=89939,default_permissions,allow_other)

[dbq-andersons]

@Tulsishah , that makes sense for the rw vs. ro. Being a UNIX jockey for almost 30 years, I should have known that. Duh...

As for the config file fun and games, I updated my /etc/fstab line and /etc/gcsfuse.yaml to these:

bucket-name2 /bucket/mount/point2 gcsfuse _netdev,uid=2001,config_file=/etc/gcsfuse.yaml

file-system:
  dir-mode: "775"
  file-mode: "664"
  gid: "33"
  fuse-options: allow_other
only-dir: "photos"

I am still not seeing the allow_other option being applied in the mount command output and non-root users still have no access.

"FileMode":"664","FuseOptions":["rw"],"Gid":33

Is there something else I'm missing?

[Tulsishah]

@dbq-andersons, I am now able to reproduce your issue. The problem occurs specifically when mounting GCSFuse as the root user (via /etc/fstab). I did not encounter this issue with a standard GCSFuse mount. I will check with the team and update you soon.

[dbq-andersons]

Just for kicks, I changed the rw in the yaml file to "ro" and that's not being applied either. Hoswever, if I add the "ro" option ot the /etc/fstab line, then it does get applied.

It doesn't appear that any of the fuse-options are being read from the .yaml file?

[vipnydav]

GCSFuse applies settings in a specific order: built-in defaults < config file settings < command line flags.

The main issue arises when using /etc/fstab because the kernel itself might pass default mount options (like rw). GCSFuse gives these /etc/fstab-level options the highest priority, treating them like command-line flags.

Because of this high priority, these /etc/fstab options will override any conflicting settings that is defined specifically within the file-system:fuse-options: section of the GCSFuse config file. This conflict doesn't happen while running gcsfuse directly using the --config-file flag.

It's important to know that only the file-system:fuse-options are affected by this specific override behavior when using /etc/fstab. Other settings in the config file (outside that specific section) should still be applied correctly.

Workaround:

• Keep most of the settings in the config file.
• Move only the FUSE-specific options (like ro, allow_other, uid, gid, etc.) out of the file-system:fuse-options: section of the config file and add them directly into the options field of /etc/fstab entry.
• Example /etc/fstab line:
  <bucket-name> <mount-point> fuse.gcsfuse allow_other,ro,config_file=/path/to/config.yaml

[ashmeenkaur]

This seems like something that we can solve in the GCSFuse layer, I've raised a PR to fix it

• [Bug fix] ignore rw option passed as CLI flag during persistent mounting #3168

[dbq-andersons]

Thanks @vipnydav and @ashmeenkaur for your responses.

I have left the allow_other flag in the /etc/fstab lines for now. This shouldn't be a problem moving forward since it's just the one flag. I have put the longer variables in the /etc/gcsfuse.yaml config file and they're working fine.

Thanks,

Bill

[ashmeenkaur]

PR merged and will be part of our next release. Thanks @dbq-andersons!