Re: A question about extended attributes of filesystem objects (setfattr command)

[Jacky Malcles <Jacky.Malcles@bull.net>]

Michael Kerrisk wrote:
> 
> Gidday,
> 
> > I have a question regarding
> >  Attributes of symlinks vs. the files pointed to
> >
> > If I try to attach name:value pair to object symlink file
> > then I'll get: "Operation not permitted"
> 
> What file system are you using?  If ext2, ext3 (or patched kernel
> supporting Reiserfs EAs), did you mount with "-o user_xattr?
> (The above error suggests you haven't used this option.)

# mount
/dev/sdb3 on /a type ext3 (rw,acl,user_xattr)
...etc...


> 
> > reading the man pages of setfattr (or attr) I thought that it operates
> > on the attributes of  the  symbolic link itself.
> 
> No, these commands follow symbolic links.
> 
> > show:
> > -----
> > touch f
> > ln -s f l
> > setfattr -n user.filename -v ascii1 f l
> > setfattr -h -n user.filename  -v ascii2 f
> > getfattr -d f l
> > setfattr -h -n user.filename  -v ascii3 l
> > setfattr -h --no-dereference -n user.filename  -v ascii4 l
> > getfattr -d f l
> >
> > so, my question is : what is expected ?
should have added this:

[root@t20 acl]# show
# file: f
user.filename="ascii2"

# file: l
user.filename="ascii2"

setfattr: l: Operation not permitted
setfattr: l: Operation not permitted
# file: f
user.filename="ascii2"

# file: l
user.filename="ascii2"

[root@t20 acl]#

> 
> attr(5) specifically notes that USER EAs are disallowed on
> symbolic links, but this is rather an issu that affects the
> use of lsetxattr(2).
> 
> Cheers,
> 
> Michael
> 
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-- 
 Jacky Malcles    	     B1-403   Email : Jacky.Malcles@bull.net
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