This patch adds a persistent, read-only caching facility for
9p clients using the FS-Cache caching backend.

When the fscache facility is enabled, each inode is associated
with a corresponding vcookie which is an index into the FS-Cache
indexing tree. The FS-Cache indexing tree is indexed at 3 levels:
- session object associated with each mount.
- inode/vcookie
- actual data (pages)

A cache tag is chosen randomly for each session. These tags can
be read off /sys/fs/9p/caches and can be passed as a mount-time
parameter to re-attach to the specified caching session.
Signed-off-by: NAbhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Fixes build problem with 9p when building with debug disabled.
Also contains some fixes for warnings which pop up when 
CONFIG_NET_9P_DEBUG is disabled.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The new debug support lacks some of the information that the previous fcprint
code provided -- this patch focuses on better presentation of debug data along
with more helpful debug along error paths.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Remove depricated conv functions which have been replaced with new 
protocol routines.

This patch also reworks the one instance of the file-system code which
directly calls conversion routines (to accomplish unpacking dirreads).
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Now that the new protocol functions are in place, this patch switches
the client code to using the new support code.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

One of the current debug options allows users to get a verbose dump of fcalls.
This isn't really necessary as correctly parsed protocol frames can be printed
as part of the code in the client functions.  The consolidated printfcalls
structure would require new entries to be added for every extension.  This
patch removes the debug print methods and their use.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This adds a new protocol processing support code based on Anthony Liguori's
9p library code.  This code performs protocol marshalling/unmarshalling using
printf like strings to represent protocol elements.  It is my intent to use
them to replace the current functions in conv.c as well as the 
p9_create_* functions.

This should make the client implementation much more clear, and also make it
much easier to add new protocol extensions by limiting the number of places
in which changes need to be made.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

9p trans modules aren't refcounted nor were they unregistered
properly.  Fix it.

* Add 9p_trans_module->owner and reference the module on each trans
  instance creation and put it on destruction.

* Protect v9fs_trans_list with a spinlock.  This isn't strictly
  necessary as the list is manipulated only during module loading /
  unloading but it's a good idea to make the API safe.

* Unregister trans modules when the corresponding module is being
  unloaded.

* While at it, kill unnecessary EXPORT_SYMBOL on p9_trans_fd_init().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

There was some cleanup issues during early mount which would trigger
a kernel bug for certain types of failure.  This patch reorganizes the
cleanup to get rid of the bad behavior.

This also merges the 9pnet and 9pnet_fd modules for the purpose of
configuration and initialization.  Keeping the fd transport separate
from the core 9pnet code seemed like a good idea at the time, but in
practice has caused more harm and confusion than good.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The kernel-doc comments of much of the 9p system have been in disarray since
reorganization.  This patch fixes those problems, adds additional documentation
and a template book which collects the 9p information.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

GDM gets unhappy if /var/gdm doesn't have the sticky bit set.  This patch adds
support for the sticky bit in much the same way setuid/setgid is supported.

With this patch, I can launch X from a v9fs rootfs (although I quickly run out
of fds in the server once gnome starts up).
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Acked-by: NEric Van Hensbergen <ericvh@gmail.com>

The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.

The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.

[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A sysctl method was added to enable and disable debugging levels.  After
further review, it was decided that there are better approaches to doing this
and the sysctl methodology isn't really desirable.  This patch removes the
sysctl code from 9p.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>
  

The 9P2000 protocol requires the authentication and permission checks to be
done in the file server. For that reason every user that accesses the file
server tree has to authenticate and attach to the server separately.
Multiple users can share the same connection to the server.

Currently v9fs does a single attach and executes all I/O operations as a
single user. This makes using v9fs in multiuser environment unsafe as it
depends on the client doing the permission checking.

This patch improves the 9P2000 support by allowing every user to attach
separately. The patch defines three modes of access (new mount option
'access'):

- attach-per-user (access=user) (default mode for 9P2000.u)
 If a user tries to access a file served by v9fs for the first time, v9fs
 sends an attach command to the server (Tattach) specifying the user. If
 the attach succeeds, the user can access the v9fs tree.
 As there is no uname->uid (string->integer) mapping yet, this mode works
 only with the 9P2000.u dialect.

- allow only one user to access the tree (access=<uid>)
 Only the user with uid can access the v9fs tree. Other users that attempt
 to access it will get EPERM error.

- do all operations as a single user (access=any) (default for 9P2000)
 V9fs does a single attach and all operations are done as a single user.
 If this mode is selected, the v9fs behavior is identical with the current
 one.
Signed-off-by: NLatchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

found via make randconfig build testing: 

 net/built-in.o: In function `init_p9':
 mod.c:(.init.text+0x3b39): undefined reference to `p9_sysctl_register'
 net/built-in.o: In function `exit_p9':
 mod.c:(.exit.text+0x36b): undefined reference to `p9_sysctl_unregister'
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patchset moves non-filesystem interfaces of v9fs from fs/9p to net/9p.
It moves the transport, packet marshalling and connection layers to net/9p
leaving only the VFS related files in fs/9p.  This work is being done in
preparation for in-kernel 9p servers as well as alternate 9p clients (other
than VFS).
Signed-off-by: NLatchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>