Add new mount V9FS mount option to specify protocol version

This patch adds a new mount option to specify protocol version.
With this option it is possible to use "-o version=" switch to
specify 9P protocol version to use. Valid options for version
are:
9p2000
9p2000.u
9p2010.L
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Add 9P2000.u and 9P2010.L protocol flags to V9FS VFS

This patch adds 9P2000.u and 9P2010.L protocol flags into V9FS VFS side code
and removes the single flag used for 'extended'.
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

With this patch we have

# mount -t 9p -o trans=virtio virtio2 /mnt/
# mount -t 9p -o trans=virtio virtio2 /mnt/
mount: virtio2 already mounted or /mnt/ busy
mount: according to mtab, virtio2 is already mounted on /mnt
# mount -t 9p -o trans=virtio virtio3 /mnt/ -o debug=0xfff
mount: special device virtio3 does not exist
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Use a list to track the channel instead of statically
allocated array
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This is needed for supporting multiple mount points.

We can find out the device names to be used with mount by checking

/sys/devices/virtio-pci/virtio*/device file

if the device file have value 9 then the specific virtio device can
be used for mounting.

ex:
 #cat /sys/devices/virtio-pci/virtio1/device
 9

now we can mount using
# mount -t 9p -o trans=virtio virtio1  /mnt/
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

* 'for-linus' of git://git.open-osd.org/linux-open-osd:
  exofs: groups support
  exofs: Prepare for groups
  exofs: Error recovery if object is missing from storage
  exofs: convert io_state to use pages array instead of bio at input
  exofs: RAID0 support
  exofs: Define on-disk per-inode optional layout attribute
  exofs: unindent exofs_sbi_read
  exofs: Move layout related members to a layout structure
  exofs: Recover in the case of read-passed-end-of-file
  exofs: Micro-optimize exofs_i_info
  exofs: debug print even less

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Make prom entry spinlock NMI safe.
  sparc64: Kill off old sys_perfctr system call and state.
  sparc: Update defconfigs.
  sparc: Provide io{read,write}{16,32}be().

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-next-2.6: (49 commits)
  drivers/ide: Fix continuation line formats
  ide: fixed section mismatch warning in cmd640.c
  ide: ide_timing_compute() fixup
  ide: make ide_get_best_pio_mode() static
  via82cxxx: use ->pio_mode value to determine pair device speed
  tx493xide: use ->pio_mode value to determine pair device speed
  siimage: use ->pio_mode value to determine pair device speed
  palm_bk3710: use ->pio_mode value to determine pair device speed
  it821x: use ->pio_mode value to determine pair device speed
  cs5536: use ->pio_mode value to determine pair device speed
  cs5535: use ->pio_mode value to determine pair device speed
  cmd64x: fix handling of address setup timings
  amd74xx: use ->pio_mode value to determine pair device speed
  alim15x3: fix handling of UDMA enable bit
  alim15x3: fix handling of DMA timings
  alim15x3: fix handling of command timings
  alim15x3: fix handling of address setup timings
  ide-timings: use ->pio_mode value to determine fastest PIO speed
  ide: change ->set_dma_mode method parameters
  ide: change ->set_pio_mode method parameters
  ...

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (28 commits)
  ioat: cleanup ->timer_fn() and ->cleanup_fn() prototypes
  ioat3: interrupt coalescing
  ioat: close potential BUG_ON race in the descriptor cleanup path
  ioat2: kill pending flag
  ioat3: use ioat2_quiesce()
  ioat3: cleanup, don't enable DCA completion writes
  DMAENGINE: COH 901 318 lli sg offset fix
  DMAENGINE: COH 901 318 configure channel direction
  DMAENGINE: COH 901 318 remove irq counting
  DMAENGINE: COH 901 318 descriptor pool refactoring
  DMAENGINE: COH 901 318 cleanups
  dma: Add MPC512x DMA driver
  Debugging options for the DMA engine subsystem
  iop-adma: redundant/wrong tests in iop_*_count()?
  dmatest: fix handling of an even number of xor_sources
  dmatest: correct raid6 PQ test
  fsldma: Fix cookie issues
  fsldma: Fix cookie issues
  dma: cases IPU_PIX_FMT_BGRA32, BGR32 and ABGR32 are the same in ipu_ch_param_set_size()
  dma: make Open Firmware device id constant
  ...

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits)
  init: Open /dev/console from rootfs
  mqueue: fix typo "failues" -> "failures"
  mqueue: only set error codes if they are really necessary
  mqueue: simplify do_open() error handling
  mqueue: apply mathematics distributivity on mq_bytes calculation
  mqueue: remove unneeded info->messages initialization
  mqueue: fix mq_open() file descriptor leak on user-space processes
  fix race in d_splice_alias()
  set S_DEAD on unlink() and non-directory rename() victims
  vfs: add NOFOLLOW flag to umount(2)
  get rid of ->mnt_parent in tomoyo/realpath
  hppfs can use existing proc_mnt, no need for do_kern_mount() in there
  Mirror MS_KERNMOUNT in ->mnt_flags
  get rid of useless vfsmount_lock use in put_mnt_ns()
  Take vfsmount_lock to fs/internal.h
  get rid of insanity with namespace roots in tomoyo
  take check for new events in namespace (guts of mounts_poll()) to namespace.c
  Don't mess with generic_permission() under ->d_lock in hpfs
  sanitize const/signedness for udf
  nilfs: sanitize const/signedness in dealing with ->d_name.name
  ...

Fix up fairly trivial (famous last words...) conflicts in
drivers/infiniband/core/uverbs_main.c and security/tomoyo/realpath.c

* git://git.infradead.org/battery-2.6:
  power_supply: bq27x00: fix voltage and current units
  power_supply: bq27x00: add status and time properties
  power_supply: bq27x00: add BQ27500 support
  power_supply: bq27x00: fix temperature conversion
  power_supply: bq27x00: remove unused struct fields
  power_supply: bq27x00: remove double endian swap
  da9030_battery: fix spelling in comment
  wm97xx_battery: Clean up some warnings

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6: (27 commits)
  Regulators: wm8400 - cleanup platform driver data handling
  Regulators: wm8994 - clean up driver data after removal
  Regulators: wm831x-xxx - clean up driver data after removal
  Regulators: pcap-regulator - clean up driver data after removal
  Regulators: max8660 - annotate probe and remove methods
  Regulators: max1586 - annotate probe and remove methods
  Regulators: lp3971 - fail if platform data was not supplied
  Regulators: tps6507x-regulator - mark probe method as __devinit
  Regulators: tps65023-regulator - mark probe method as __devinit
  Regulators: twl-regulator - mark probe function as __devinit
  Regulators: fixed - annotate probe and remove methods
  Regulators: ab3100 - fix probe and remove annotations
  Regulators: virtual - use sysfs attribute groups
  twl6030: regulator: Configure STATE register instead of REMAP
  regulator: Provide optional dummy regulator for consumers
  regulator: Assume regulators are enabled if they don't report anything
  regulator: Convert fixed voltage regulator to use enable_time()
  regulator: Add WM8994 regulator support
  regulator: enable max8649 regulator driver
  regulator: trivial: fix typos in user-visible Kconfig text
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6:
  pcmcia: disable pcmcia ioctl for !ARM, prepare for removal
  pcmcia: CodingStyle fixes
  pcmcia: alchemy: fixup wrong comments
  pcmcia: remove irq_list parameter from pd6729
  yenta_socket: ENE CB712 CardBus bridge needs special treatment with Echo Audio Indigo soundcards

* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (151 commits)
  vga_switcheroo: disable default y by new rules.
  drm/nouveau: fix *staging* driver build with switcheroo off.
  drm/radeon: fix typo in Makefile
  vga_switcheroo: fix build on platforms with no ACPI
  drm/radeon: Fix printf type warning in 64bit system.
  drm/radeon/kms: bump the KMS version number for square tiling support.
  vga_switcheroo: initial implementation (v15)
  drm/radeon/kms: do not disable audio engine twice
  Revert "drm/radeon/kms: disable HDMI audio for now on rv710/rv730"
  drm/radeon/kms: do not preset audio stuff and start timer when not using audio
  drm/radeon: r100/r200 ums: block ability for userspace app to trash 0 page and beyond
  drm/ttm: fix function prototype to match implementation
  drm/radeon: use ALIGN instead of open coding it
  drm/radeon/kms: initialize set_surface_reg reg for rs600 asic
  drm/i915: Use a dmi quirk to skip a broken SDVO TV output.
  drm/i915: enable/disable LVDS port at DPMS time
  drm/i915: check for multiple write domains in pin_and_relocate
  drm/i915: clean-up i915_gem_flush_gpu_write_domain
  drm/i915: reuse i915_gpu_idle helper
  drm/i915: ensure lru ordering of fence_list
  ...

Fixed trivial conflicts in drivers/gpu/vga/Kconfig

If the calling convention of ->timer_fn() and ->cleanup_fn() are unified
across hardware versions we can drop parameters to ioat_init_channel() and
unify ioat_is_dma_complete() implementations.

Both ->timer_fn() and ->cleanup_fn() are modified to expect a struct
dma_chan pointer.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The hardware automatically disables further interrupts after each event
until rearmed.  This allows a delay to be injected between the occurence
of the interrupt and the running of the cleanup routine.  The delay is
scaled by the descriptor backlog and then written to the INTRDELAY
register which specifies the number of microseconds to hold off
interrupt delivery after an interrupt event occurs.  According to
powertop this reduces the interrupt rate from ~5000 intr/s to ~150
intr/s per without affecting throughput (simple dd to a raid6 array).
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Since ioat_cleanup_preamble() and the update of the last completed
descriptor are not synchronized there is a chance that two cleanup threads
can see descriptors to clean.  If the first cleans up all pending
descriptors then the second will trigger the BUG_ON.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This makes sure that we pick the synchronous signals caused by a
processor fault over any pending regular asynchronous signals sent to
use by [t]kill().

This is not strictly required semantics, but it makes it _much_ easier
for programs like Wine that expect to find the fault information in the
signal stack.

Without this, if a non-synchronous signal gets picked first, the delayed
asynchronous signal will have its signal context pointing to the new
signal invocation, rather than the instruction that caused the SIGSEGV
or SIGBUS in the first place.

This is not all that pretty, and we're discussing making the synchronous
signals more explicit rather than have these kinds of implicit
preferences of SIGSEGV and friends.  See for example

	http://bugzilla.kernel.org/show_bug.cgi?id=15395

for some of the discussion.  But in the meantime this is a simple and
fairly straightforward work-around, and the whole

	if (x & Y)
		x &= Y;

thing can be compiled into (and gcc does do it) just three instructions:

	movq    %rdx, %rax
	andl    $Y, %eax
	cmovne  %rax, %rdx

so it is at least a simple solution to a subtle issue.
Reported-and-tested-by: NPavel Vilim <wylda@volny.cz>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To avoid potential problems with an empty /dev open /dev/console
from rootfs instead of waiting to mount our root filesystem and
mounting it there.   This effectively guarantees that there will
be a device node, and it won't be on a filesystem that we will
ever unmount, so there are no issues with leaving /dev/console
open and pinning the filesystem.

This is actually more effective than automatically mounting
devtmpfs on /dev because it removes removes the occasionally
problematic assumption that /dev/console exists from the boot
code.

With this patch I was able to throw busybox on my /boot partition
(which has no /dev directory) and boot into userspace without
problems.

The only possible negative consequence I can think of is that
someone out there deliberately used did not use a character device
that is major 5 minor 2 for /dev/console.  Does anyone know of a
situation in which that could make sense?
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... postponing assignments until they're needed. Doesn't change code size.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It reduces code size:
text    data     bss     dec     hex filename
9925      72      16   10013    271d ipc/mqueue-BEFORE.o
9885      72      16    9973    26f5 ipc/mqueue-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Code size reduction:
   text    data     bss     dec     hex filename
   9941      72      16   10029    272d ipc/mqueue-BEFORE.o
   9925      72      16   10013    271d ipc/mqueue-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and abort earlier if we couldn't allocate the message pointers array,
avoiding the u->mq_bytes accounting logic.

It reduces code size:
   text    data     bss     dec     hex filename
   9949      72      16   10037    2735 ipc/mqueue-BEFORE.o
   9941      72      16   10029    272d ipc/mqueue-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We leak fd on lookup_one_len() failure
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

rehashing the negative placeholder opens a race with d_lookup();
we unhash it almost immediately (by d_move()), but the race
window is there.  Since d_move() doesn't rely on target being
hashed, we don't need that d_rehash() at all.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a new UMOUNT_NOFOLLOW flag to umount(2).  This is needed to prevent
symlink attacks in unprivileged unmounts (fuse, samba, ncpfs).

Additionally, return -EINVAL if an unknown flag is used (and specify
an explicitly unused flag: UMOUNT_UNUSED).  This makes it possible for
the caller to determine if a flag is supported or not.

CC: Eugene Teo <eugene@redhat.com>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It hadn't been needed since we'd sanitized the logics in
mark_mounts_for_expiry() (which, in turn, used to be a
rudiment of bad old times when namespace_sem was per-ns).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

no more users left outside of fs/*.c (and very few outside of
fs/namespace.c, actually)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

passing *any* namespace root to __d_path() as root is equivalent
to just passing it {NULL, NULL}; no need to bother with finding
the root of our namespace in there.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just use dentry_unhash() there
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>