2008-02-11 17:06:27

by Rok Ruzic

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Subject: reading user. extended attributes from symlinks in 2.6 kernels

Hello,

I have an XFS filesystem containing files and symlinks with application-specific EAs in the user namespace. The files, symlinks and their EAs were created while running a 2.4 kernel.

In 2.6 kernels access to user EAs was prevented for symlinks. My problem is that i have to upgrade the kernel from 2.4 to 2.6 series and i have to have access to all the EAs after upgrade. Is there a way to read user EAs off of symlinks on an XFS filesystem on a 2.6 kernel either from userspace or from a filter driver sitting between VFS and XFS filesystem code?

I would appreciate it very much if somebody could point me towards a solution.

Rok


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2008-02-14 16:42:17

by Bill Davidsen

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Subject: Re: reading user. extended attributes from symlinks in 2.6 kernels

Rok Ruzic wrote:
> Hello,
>
> I have an XFS filesystem containing files and symlinks with application-specific EAs in the user namespace. The files, symlinks and their EAs were created while running a 2.4 kernel.
>
> In 2.6 kernels access to user EAs was prevented for symlinks. My
problem is that i have to upgrade the kernel from 2.4 to 2.6 series and
i have to have access to all the EAs after upgrade. Is there a way to
read user EAs off of symlinks on an XFS filesystem on a 2.6 kernel
either from userspace or from a filter driver sitting between VFS and
XFS filesystem code?
>
> I would appreciate it very much if somebody could point me towards a solution.
>
If you want to do it at user code level, you could note the symlink,
follow it to the "real" name, and read the EA there. I don't see any
easy way to force the kernel to follow the symlink.


--
Bill Davidsen <[email protected]>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot