v9fs_fid_xattr_set is supposed to return 0 on success.

This corrects the behaviour introduced in commit
bdd5c28d
"9p: fix return value in case in v9fs_fid_xattr_set()"

(The function returns a negative error on error, as expected)
Signed-off-by: NDominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

In case of error in the p9_client_write, the function v9fs_fid_xattr_set
should return its negative value, what was never being done.

In case of success it only retuned 0. Now it returns the 'offset'
variable (write_count total).
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Allow requests for security.* and trusted.* xattr name spaces
to pass through to server.

The new files are 99% cut and paste from fs/9p/xattr_user.c with the
namespaces changed.  It has the intended effect in superficial testing.
I do not know much detail about how these namespaces are used, but passing
them through to the server, which can decide whether to handle them or not,
seems reasonable.

I want to support a use case where an ext4 file system is mounted via 9P,
then re-exported via samba to windows clients in a cluster.  Windows wants
to store xattrs such as security.NTACL.  This works when ext4 directly
backs samba, but not when 9P is inserted.  This use case is documented here:
   http://code.google.com/p/diod/issues/detail?id=95Signed-off-by: NJim Garlick <garlick@llnl.gov>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

... making v9fs_xattr_set() a wrapper for it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Reduce object size by deduplicating formats.

Use vsprintf extension %pV.
Rename P9_DPRINTK uses to p9_debug, align arguments.
Add function for _p9_debug and macro to add __func__.
Add missing "\n"s to p9_debug uses.
Remove embedded function names as p9_debug adds it.
Remove P9_EPRINTK macro and convert use to pr_<level>.
Add and use pr_fmt and pr_<level>.

$ size fs/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  62133	    984	  16000	  79117	  1350d	fs/9p/built-in.o.new
  67342	    984	  16928	  85254	  14d06	fs/9p/built-in.o.old
$ size net/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  88792	   4148	  22024	 114964	  1c114	net/9p/built-in.o.new
  94072	   4148	  23232	 121452	  1da6c	net/9p/built-in.o.old
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch implement fetching POSIX ACL from the server
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The ACL value is fetched as a part of inode initialization
from the server and the permission checking function use the
cached value of the ACL
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

fixes:

  CHECK   fs/9p/xattr.c
	fs/9p/xattr.c:73:6: warning: Using plain integer as NULL pointer
	fs/9p/xattr.c:135:6: warning: Using plain integer as NULL pointer
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>