* Semantics of setting an extended attribute to empty vs removexattr?
@ 2008-09-24 22:19 Daniel Phillips
2008-09-24 23:41 ` Nathan Scott
0 siblings, 1 reply; 3+ messages in thread
From: Daniel Phillips @ 2008-09-24 22:19 UTC (permalink / raw)
To: linux-fsdevel
Hi,
Does anybody have an opinion on whether setting an extended attribute
to empty using the setxattr interface is supposed to be semantically
equivalent to removing the xattr using removexattr?
I rather wish this were the case in the interest of a robust usage
model, but I pessimistically expect to learn that, no, an empty xattr
is indeed different from an nonexistent xattr, similer to environment
variables.
Regards,
Daniel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Semantics of setting an extended attribute to empty vs removexattr?
2008-09-24 22:19 Semantics of setting an extended attribute to empty vs removexattr? Daniel Phillips
@ 2008-09-24 23:41 ` Nathan Scott
2008-09-25 0:38 ` Daniel Phillips
0 siblings, 1 reply; 3+ messages in thread
From: Nathan Scott @ 2008-09-24 23:41 UTC (permalink / raw)
To: Daniel Phillips; +Cc: linux-fsdevel
On Wed, 2008-09-24 at 15:19 -0700, Daniel Phillips wrote:
> Hi,
>
> Does anybody have an opinion on whether setting an extended attribute
> to empty using the setxattr interface is supposed to be semantically
> equivalent to removing the xattr using removexattr?
attr(5) states...
NAME
attr - Extended attributes
DESCRIPTION
Extended attributes are name:value pairs associated permanently with
files and directories, similar to the environment strings associated
with a process. An attribute may be defined or undefined. If it is
defined, its value may be empty or non-empty.
XFS and extN certainly implement this property, I'd imagine all of the
other filesystems supporting extended attributes do as well.
cheers.
--
Nathan
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Semantics of setting an extended attribute to empty vs removexattr?
2008-09-24 23:41 ` Nathan Scott
@ 2008-09-25 0:38 ` Daniel Phillips
0 siblings, 0 replies; 3+ messages in thread
From: Daniel Phillips @ 2008-09-25 0:38 UTC (permalink / raw)
To: Nathan Scott; +Cc: linux-fsdevel
On Wednesday 24 September 2008 16:41, Nathan Scott wrote:
> On Wed, 2008-09-24 at 15:19 -0700, Daniel Phillips wrote:
> > Hi,
> >
> > Does anybody have an opinion on whether setting an extended attribute
> > to empty using the setxattr interface is supposed to be semantically
> > equivalent to removing the xattr using removexattr?
>
> attr(5) states...
>
> NAME
> attr - Extended attributes
>
> DESCRIPTION
> Extended attributes are name:value pairs associated permanently with
> files and directories, similar to the environment strings associated
> with a process. An attribute may be defined or undefined. If it is
> defined, its value may be empty or non-empty.
>
>
> XFS and extN certainly implement this property, I'd imagine all of the
> other filesystems supporting extended attributes do as well.
Yes, and Tux3 will be revised to toe the line, it's no big deal. Thanks
for reading me the man page :-/
Regards,
Daniel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2008-09-24 22:19 Semantics of setting an extended attribute to empty vs removexattr? Daniel Phillips
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2008-09-25 0:38 ` Daniel Phillips
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