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Univ426
Asked: 2012-08-28 06:24:24 +0800 CST

Disabling/Enabling Modules Parameter RHEL

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I'm working with kernel module parameters, and I've found myself a bit confused.

In particular, I'm attempting to enable posix ACL support for XFS file systems. This requires the XFS module to be loaded with the parameter XFS_POSIX_ACL set to yes. Without it, attempts to set ACL's with "setfacl" result in "Operation not supported" errors.

In a test environment, I ran the command "modprobe -v xfs XFS_POSIX_ACL=y". Despite now knowing that you need to first remove a module before you can set parameters, this command appeared to have worked. After running it, I was successfully able to run "setfacl", set some ACL's and test them with full functionality.

Moving over to production though, it appears - not surprisingly - that simply running "modprobe -v xfs XFS_POSIX_ACL=y" doesn't seem to enable ACL support, likely due to the fact that I haven't unloaded the module first. Running the command produces no output, and attempts to set an ACL result in "Operation not supported" errors.

The problem I'm having, is that after going back to my test environment and attempting to "flip the parameters switch properly," running modprobe -r xfs followed by "modprobe -v xfs XFS_POSIX_ACL=n" doesn't turn off ACL support. I've run modprobe -r in verbose mode, and the module is in fact unloaded (rmmod /lib/modules/...xfs.ko) , but reloading it with the ACL parameter set to NO has no effect.

Any ideas what I might be doing wrong?

RHEL 4.9, 2.6.9-89

Update

It looks like I have the parameter wrong. Looking at dmesg after running modprobe xfs XFS_POSIX_ACL=N:

xfs: Unknown parameter `XFS_POSIX_ACL'
SGI XFS with ACLs, security attributes, large block/inode numbers, no debug enabled
SGI XFS Quota Management subsystem

I found the ACL parameter here: http://how-to.wikia.com/wiki/How_to_configure_the_Linux_kernel/fs/xfs

Any idea what the proper parameter might be? modinfo -p xfs returns nothing and I'm having a heck of a time finding it online.

kernel

1 Answers

  1. Best Answer

    @John K: all the options in the link which you posted above are not parameters for xfs module, they are dependencies options.

    xfs module has... no params:

    # modinfo xfs
filename:       /lib/modules/2.6.18-194.el5/kernel/fs/xfs/xfs.ko
license:        GPL
description:    SGI XFS with ACLs, security attributes, large block/inode numbers, no debug enabled
author:         Silicon Graphics, Inc.
srcversion:     DE0AE7E45DF5E1EA03F6EC6
depends:        
vermagic:       2.6.18-194.el5 SMP mod_unload gcc-4.1
module_sig: 883f3504bb64522c596239a507de7fd112864709d128ea990dfa46df295317acd048b4a6cd39abde0a0beb9a93708040775f3bac9d185e1eb73cda7c

    By dependencies, I mean: XFS Quota, ACL, ... are expand only when you selecting XFS filesystem support:

    <M> XFS filesystem support                
[ ]   XFS Quota support                   
[*]   XFS POSIX ACL support               
[ ]   XFS Realtime subvolume support      
[ ]   XFS Debugging support (EXPERIMENTAL)
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