Re: "xfs_io -c chattr +i " on a symlink

Re: "xfs_io -c chattr +i " on a symlink

[Dan Am]

On Fri, August 4, 2006 6:20 am, Chris Wedgwood wrote:
> I always disliked open/ioctl for this.  I think we should actually have
a separate syscall for chattr, etc. (FreeBSD does this I think?)
So how does "attr -s someAttribute symlink" work ? This does the job very
well, distinguishing it from other filesystems.

Best
Dan

Re: "xfs_io -c chattr +i " on a symlink

[Timothy Shimmin]

Dan Am wrote:
> On Fri, August 4, 2006 6:20 am, Chris Wedgwood wrote:
>> I always disliked open/ioctl for this.  I think we should actually have
>> a separate syscall for chattr, etc. (FreeBSD does this I think?)
 >
> So how does "attr -s someAttribute symlink" work ? This does the job very
> well, distinguishing it from other filesystems.
> 

attr(1) sets the extended attribute and they are set by system calls.
It looks like you would need the -L option to attr(1) which ends up
calling the lsetxattr() syscall via the libattr library.
(Inode attributes shouldn't be confused with extended attributes, EAs, -
  a cause of much confusion for me and others in the past :)

--Tim

"xfs_io -c chattr +i " on a symlink

[Dan Am]

(resend, since I used the wrong account to send the initial mail, sorry)

Dear list,

I am trying to make a symlink immutable with chattr, however the command
seems to follow the link, which point to a NFS Mount.
Setting xattr works on symlink btw, which is useful.
More data below
Any ideas ?

Best Regards
Dan

Heres the situation from my machine's view:
/data > ls -l bin
lrwxrwxrwx  1 root root 48 Aug  2 15:53 bin -> /archive/l01abnfs07/bin

/data> xfs_io  -c "chattr +i" bin
xfs_io: specified file ["bin"] is not on an XFS filesystem

~ > xfs_io -V
xfs_io version 2.8.4

~ > cat /etc/SuSE-release
SUSE LINUX Enterprise Server 9 (i586)
VERSION = 9
PATCHLEVEL = 3

Re: "xfs_io -c chattr +i " on a symlink

[Eric Sandeen]

Dan Am wrote:
> (resend, since I used the wrong account to send the initial mail, sorry)
> 
> Dear list,
> 
> I am trying to make a symlink immutable with chattr, however the command
> seems to follow the link, which point to a NFS Mount.
> Setting xattr works on symlink btw, which is useful.
> More data below
> Any ideas ?
> 
> Best Regards
> Dan
> 
> Heres the situation from my machine's view:
> /data > ls -l bin
> lrwxrwxrwx  1 root root 48 Aug  2 15:53 bin -> /archive/l01abnfs07/bin
> 
> /data> xfs_io  -c "chattr +i" bin
> xfs_io: specified file ["bin"] is not on an XFS filesystem
> 
> ~ > xfs_io -V
> xfs_io version 2.8.4

Try just using chattr.

[sandeen@sandeen ~]$ ln -s /tmp tmplink
[sandeen@sandeen ~]$ ls -l tmplink
lrwxrwxrwx  1 sandeen sandeen 4 Aug  3 09:05 tmplink -> /tmp
[sandeen@sandeen ~]$ su
Password:
[root@sandeen sandeen]# chattr +i tmplink
[root@sandeen sandeen]# stat -f tmplink
   File: "tmplink"
     ID: 802      Namelen: 255     Type: XFS (0x58465342)
Blocks: Total: 23377204   Free: 8557099    Available: 8557099    Size: 4096
Inodes: Total: 93554496   Free: 93202008
[root@sandeen sandeen]#
[root@sandeen sandeen]# lsattr tmplink
----i-------- tmplink

xfs_io also has an option to try to do operations even on non-xfs filesystems, 
if that helps... if it follows the link & sets the attr on the link target, that 
may not be behaving as expected though.

-Eric

Re: "xfs_io -c chattr +i " on a symlink

[Nathan Scott]

On Thu, Aug 03, 2006 at 09:13:07AM -0500, Eric Sandeen wrote:
> Try just using chattr.

Or not. :)

> [sandeen@sandeen ~]$ ln -s /tmp tmplink
> [sandeen@sandeen ~]$ ls -l tmplink
> lrwxrwxrwx  1 sandeen sandeen 4 Aug  3 09:05 tmplink -> /tmp
> [sandeen@sandeen ~]$ su
> Password:
> [root@sandeen sandeen]# chattr +i tmplink
> [root@sandeen sandeen]# stat -f tmplink
>    File: "tmplink"
>      ID: 802      Namelen: 255     Type: XFS (0x58465342)
> Blocks: Total: 23377204   Free: 8557099    Available: 8557099    Size: 4096
> Inodes: Total: 93554496   Free: 93202008
> [root@sandeen sandeen]#
> [root@sandeen sandeen]# lsattr tmplink
> ----i-------- tmplink

... I think you just set immutable on /tmp.  Try a broken symlink,
instead of one that points to an existing inode.

cheers.

-- 
Nathan

Re: "xfs_io -c chattr +i " on a symlink

[Eric Sandeen]

Nathan Scott wrote:
> On Thu, Aug 03, 2006 at 09:13:07AM -0500, Eric Sandeen wrote:
>> Try just using chattr.
> 
> Or not. :)

Whoops, oh well.  Shoulda investigated a bit more I guess :)

-Eric

Re: "xfs_io -c chattr +i " on a symlink

[Dan Am]

On Fri, August 4, 2006 2:29 am, Nathan Scott wrote:

> ... I think you just set immutable on /tmp.  Try a broken symlink,
> instead of one that points to an existing inode.
Nope:
/data/tara-test > ls -l test
lrwxr-xr-x  1 root root 13 Aug  4 13:33 test -> /archive/no-such-file

/data/tara-test > xfs_io -c "chattr +i" test
test: No such file or directory

Best Regards
Dan

Re: "xfs_io -c chattr +i " on a symlink

[Nathan Scott]

On Fri, Aug 04, 2006 at 01:37:32PM +0200, Dan Am wrote:
> On Fri, August 4, 2006 2:29 am, Nathan Scott wrote:
> 
> > ... I think you just set immutable on /tmp.  Try a broken symlink,
> > instead of one that points to an existing inode.
> Nope:

Eh?

> /data/tara-test > ls -l test
> lrwxr-xr-x  1 root root 13 Aug  4 13:33 test -> /archive/no-such-file
> 
> /data/tara-test > xfs_io -c "chattr +i" test
> test: No such file or directory

Right, that was my point.  As I said, you're out of luck - there
is currently no way to do what you want.

cheers.

-- 
Nathan

Re: "xfs_io -c chattr +i " on a symlink

[Nathan Scott]

On Thu, Aug 03, 2006 at 12:26:56PM +0200, Dan Am wrote:
> (resend, since I used the wrong account to send the initial mail, sorry)
> 
> Dear list,
> 
> I am trying to make a symlink immutable with chattr, however the command
> seems to follow the link, which point to a NFS Mount.
> Setting xattr works on symlink btw, which is useful.
> More data below
> Any ideas ?

Its not possible to open(2) a symbolic link (see fs/namei.c::may_open),
which means you cannot get a file descriptor for a symlink, which means
you cannot issue an ioctl(2) to a symlink (which is how the inode flags
are set), which means you're out of luck on this one, sorry.

cheers.

-- 
Nathan

Re: "xfs_io -c chattr +i " on a symlink

[Chris Wedgwood]

On Fri, Aug 04, 2006 at 10:28:14AM +1000, Nathan Scott wrote:

> Its not possible to open(2) a symbolic link (see
> fs/namei.c::may_open), which means you cannot get a file descriptor
> for a symlink, which means you cannot issue an ioctl(2) to a symlink
> (which is how the inode flags are set), which means you're out of
> luck on this one, sorry.

I always disliked open/ioctl for this.  I think we should actually
have a separate syscall for chattr, etc. (FreeBSD does this I think?)

"xfs_io -c chattr +i " on a symlink

[Daniel Amthor]

Dear list,

I am trying to make a symlink immutable with chattr, however the command
seems to follow the link, which point to a NFS Mount.
Setting xattr works on symlink btw, which is useful.
More data below
Any ideas ?

Best Regards
Dan

Heres the situation from my machine's view:
/data > ls -l bin
lrwxrwxrwx  1 root root 48 Aug  2 15:53 bin -> /archive/l01abnfs07/bin

/data> xfs_io  -c "chattr +i" bin
xfs_io: specified file ["bin"] is not on an XFS filesystem

~ > xfs_io -V
xfs_io version 2.8.4

~ > cat /etc/SuSE-release
SUSE LINUX Enterprise Server 9 (i586)
VERSION = 9
PATCHLEVEL = 3