Thanks to Andrew for the good explanation of why this is so. akpm writes:

If a page is under writeback and we remove it from pagecache, it's still
going to get written to disk.  But the VFS no longer knows about that page,
nor that this page is about to modify disk blocks.

So there might be scenarios in which those
blocks-which-are-about-to-be-written-to get reused for something else.
When writeback completes, it'll scribble on those blocks.

This won't happen in ext2/ext3-style filesystems in normal mode because the
page has buffers and try_to_release_page() will fail.

But ext2 in nobh mode doesn't attach buffers at all - it just sticks the
page in a BIO, finds some new blocks, points the BIO at those blocks and
lets it rip.

While that write IO's in flight, someone could truncate the file.  Truncate
won't block on the writeout because the page isn't in pagecache any more.
So truncate will the free the blocks from the file under the page's feet.
Then something else can reallocate those blocks.  Then write data to them.

Now, the original write completes, corrupting the filesystem.
Signed-off-by: NJens Axboe <axboe@suse.de>

Forgot that one, thanks Jeff. Also move the other EXPORT_SYMBOL
to right below the functions.
Signed-off-by: NJens Axboe <axboe@suse.de>

This lets userspace indicate whether more data will be coming in a
subsequent splice call.
Signed-off-by: NJens Axboe <axboe@suse.de>

Hopefully this will make Andrew a little more happy.
Signed-off-by: NJens Axboe <axboe@suse.de>

By cleaning up the writeback logic (killing write_one_page() and the manual
set_page_dirty()), we can get rid of ->stolen inside the pipe_buffer and
just keep it local in pipe_to_file().

This also adds dirty page balancing logic and O_SYNC handling.
Signed-off-by: NJens Axboe <axboe@suse.de>

Clear the entire range, and don't increment pidx or we keep filling
the same position again and again.

Thanks to KAMEZAWA Hiroyuki.
Signed-off-by: NJens Axboe <axboe@suse.de>

* master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb: (49 commits)
  V4L/DVB (3667b): cpia2: fix function prototype
  V4L/DVB (3702): Make msp3400 routing defines more consistent
  V4L/DVB (3700): Remove obsolete commands from tvp5150.c
  V4L/DVB (3697): More msp3400 and bttv fixes
  V4L/DVB (3696): Previous change for cx2341X boards broke the remote support
  V4L/DVB (3693): Fix msp3400c and bttv stereo/mono/bilingual detection/handling
  V4L/DVB (3692): Keep experimental SLICED_VBI defines under an #if 0
  V4L/DVB (3689): Kconfig: fix VP-3054 Secondary I2C Bus build configuration menu dependencies
  V4L/DVB (3673): Fix budget-av CAM reset
  V4L/DVB (3672): Fix memory leak in dvr open
  V4L/DVB (3671): New module parameter 'tv_standard' (dvb-ttpci driver)
  V4L/DVB (3670): Fix typo in comment
  V4L/DVB (3669): Configurable dma buffer size for saa7146-based budget dvb cards
  V4L/DVB (3653h): Move usb v4l docs into Documentation/video4linux
  V4L/DVB (3667a): Fix SAP + stereo mode at msp3400
  V4L/DVB (3666): Remove trailing newlines
  V4L/DVB (3665): Add new NEC uPD64031A and uPD64083 i2c drivers
  V4L/DVB (3663): Fix msp3400c wait time and better audio mode fallbacks
  V4L/DVB (3662): Don't set msp3400c-non-existent register
  V4L/DVB (3661): Add wm8739 stereo audio ADC i2c driver
  ...

* 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/roland/infiniband:
  IB/ipath: kbuild infrastructure
  IB/ipath: infiniband verbs support
  IB/ipath: misc infiniband code, part 2
  IB/ipath: misc infiniband code, part 1
  IB/ipath: infiniband RC protocol support
  IB/ipath: infiniband UC and UD protocol support
  IB/ipath: infiniband header files
  IB/ipath: layering interfaces used by higher-level driver code
  IB/ipath: support for userspace apps using core driver
  IB/ipath: sysfs and ipathfs support for core driver
  IB/ipath: misc driver support code
  IB/ipath: chip initialisation code, and diag support
  IB/ipath: support for PCI Express devices
  IB/ipath: support for HyperTransport devices
  IB/ipath: core driver header files
  IB/ipath: core device driver

* master.kernel.org:/pub/scm/linux/kernel/git/brodo/pcmcia-2.6: (33 commits)
  [PATCH] pcmcia: declare pccard_iodyn_ops (fix m8xx_pcmcia.c compilation error)
  [PATCH] pcmcia: fix pcmcia_device_remove oops
  [PATCH] pcmcia: Add support for Possio GCC AKA PCMCIA Siemens MC45
  [PATCH] pcmcia: pseudo device handling update
  [PATCH] pcmcia: convert DEV_OK to pcmcia_dev_present
  [PATCH] pcmcia: use bitfield instead of p_state and state
  [PATCH] pcmcia: remove unused p_dev->state flags
  [PATCH] pcmcia: make pcmcia_release_{io,irq} static
  [PATCH] pcmcia: add return value to _config() functions
  [PATCH] pcmcia: remove dev_link_t and client_handle_t indirection
  [PATCH] pcmcia: embed dev_link_t into struct pcmcia_device
  [PATCH] pcmcia: rename pcmcia_device.state
  [PATCH] pcmcia: remove unneeded Vcc pseudo setting
  [PATCH] pcmcia: remove export of pcmcia_release_configuration
  [PATCH] pcmcia: default suspend and resume handling
  [PATCH] pcmcia: convert remaining users of pcmcia_release_io and _irq
  [PATCH] pcmcia: add pcmcia_disable_device
  [PATCH] serial_cs: add Merlin U630 IDs
  [PATCH] pcmcia: AT91RM9200 Compact Flash driver
  [PATCH] pcmcia: socket.functions starts with 1
  ...

* master.kernel.org:/pub/scm/linux/kernel/git/dtor/input: (26 commits)
  Input: add support for Braille devices
  Input: synaptics - limit rate to 40pps on Toshiba Protege M300
  Input: gamecon - add SNES mouse support
  Input: make modalias code respect allowed buffer size
  Input: convert /proc handling to seq_file
  Input: limit attributes' output to PAGE_SIZE
  Input: gameport - fix memory leak
  Input: serio - fix memory leak
  Input: zaurus keyboard driver updates
  Input: i8042 - fix logic around pnp_register_driver()
  Input: ns558 - fix logic around pnp_register_driver()
  Input: pcspkr - separate device and driver registration
  Input: atkbd - allow disabling on X86_PC (if EMBEDDED)
  Input: atkbd - disable softrepeat for dumb keyboards
  Input: atkbd - fix complaints about 'releasing unknown key 0x7f'
  Input: HID - fix duplicate key mapping for Logitech UltraX remote
  Input: use kzalloc() throughout the code
  Input: fix input_free_device() implementation
  Input: initialize serio and gameport at subsystem level
  Input: uinput - semaphore to mutex conversion
  ...

* master.kernel.org:/pub/scm/linux/kernel/git/paulus/powerpc:
  [PATCH] powerpc: iSeries needs slb_initialize to be called
  powerpc: hook up the splice syscall
  [PATCH] powerpc/cell: compile fixes
  [PATCH] powerpc: trivial spelling fixes in fault.c
  [PATCH] powerpc/pseries: EEH Cleanup
  [PATCH] powerpc/pseries: misc lparcfg fixes
  [PATCH] powerpc/pseries: fix device name printing, again.
  [PATCH] powerpc: Extends HCALL interface for InfiniBand usage
  [PATCH] powerpc/pseries: Change H_StudlyCaps to H_SHOUTING_CAPS
  [PATCH] powerpc/pseries: print message if EEH recovery fails
  [PATCH] powerpc/pseries: mutex lock to serialize EEH event processing
  powerpc: converted embedded platforms to use new define_machine support
  powerpc: merge machine_check_exception between ppc32 & ppc64

* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6:
  [SPARC]: Wire up sys_sync_file_range() into syscall tables.
  [SPARC]: Wire up sys_splice() into the syscall tables.
  [SPARC64]: Update defconfig.
  [SPARC64]: Align address in huge_pte_alloc().
  [SPARC64]: Document the instruction checks we do in do_sparc64_fault().
  [SPARC64]: Make tsb_sync() mm comparison more precise.

* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
  [NET]: Fully fix the memory leaks in sys_accept().
  [NETFILTER]: iptables 32bit compat layer
  [NETFILTER]: {ip,nf}_conntrack_netlink: fix expectation notifier unregistration
  [NETFILTER]: fix ifdef for connmark support in nf_conntrack_netlink
  [NETFILTER]: x_tables: unify IPv4/IPv6 multiport match
  [NETFILTER]: x_tables: unify IPv4/IPv6 esp match
  [NET]: Fix dentry leak in sys_accept().
  [IPSEC]: Kill unused decap state structure
  [IPSEC]: Kill unused decap state argument
  [NET]: com90xx kmalloc fix
  [TG3]: Update driver version and reldate.
  [TG3]: Revert "Speed up SRAM access"

It doesn't make the splice itself necessarily nonblocking (because the
actual file descriptors that are spliced from/to may block unless they
have the O_NONBLOCK flag set), but it makes the splice pipe operations
nonblocking.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

(We'd only added the number, which meant that actually trying
to use splice just went off into la-la-land)
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix address space warning (from sparse):
drivers/media/video/cpia2/cpia2_core.c:2355:6: error: symbol 'cpia2_read' redeclared with different type (originally declared at drivers/media/video/cpia2/cpia2.h:458) - incompatible argument 2 (different address spaces)
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Renamed various msp3400 routing defines to be more consistent and less
confusing. Esp. the MSP_DSP_OUT defines were confusing since it is really
a DSP input.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- Remove old DECODER_ commands from tvp5150.c, replacing them with newer
  ones if appropriate.
- Small VIDIOC_G_TUNER fixes in msp3400 and tuner.
- Fix VIDIOC_S_TUNER support in em28xx.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- remove obsolete VIDIOC_S_INPUT i2c call in bttv
- translate VIDIOCSFREQ to VIDIOC_S_FREQUENCY in i2c call
- improve muting during carrier scan in msp3400
- don't start scan unless really needed.
- no longer reset chip for msp3400c/d.
- remove v4l2 check in tuner-core (radio stops after using the TV)
- add missing VIDIOC_INT_ strings in v4l2-common.c
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Partially revert previous change to fix IR support.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- msp3400c did not detect the second carrier, thus being always mono.
- properly mute the msp3400c while detecting the carrier.
- fix checks on the presence of scart2/3 inputs and scart 2 output.
- implement proper audio mode fallbacks for msp3400c/d, identical to the
  way msp3400g works.
- MODE_STEREO no longer produces dual languages when set for a bilingual
  transmission, instead it falls back to LANG1. Use LANG1_LANG2 to hear
  both languages of a bilingual transmission. This is much more intuitive
  for the user and is in accordance with the preferred usage in the v4l2
  specification.
- bttv tried to implement v4l2 calls with v4l1 calls to the i2c devices,
  completely mangling the audmode/rxsubchans handling. v4l2 calls now do
  v4l2 calls to the i2c devices.
- fixed broken i2c_vidiocschan in bttv.
- add start/end lines to LOG_STATUS.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

The sliced VBI defines added in videodev2.h are removed since requires
more discussion.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

This patch fixes a dependency problem that affected the indentation order
within the individual frontend selection support menus for cx88-dvb.
- created a boolean dependency link for VIDEO_CX88_VP3054, so that
  it's tristate value will be the same as that of VIDEO_CX88_DVB.
- VIDEO_CX88_VP3054 is automatically selected by VIDEO_CX88_DVB_ALL_FRONTENDS,
  but is otherwise selected by VIDEO_CX88_DVB_VP3054, offered as an option
  under VIDEO_CX88_DVB_MT352
Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Unfortunately on the budget-av board, the CAM reset line is tied to the
frontend reset line, so resetting the CAM also zaps the frontend. This
breaks the tda1004x at least, and causes it to fail to tune until the
budget-av module is reloaded. This patch adds an exported function to dvb_frontend
that allows a card to forcibly reinitialise a frontend. The budget-av now
does this on CAM reset, which corrects this problem.
since they do not tie the CAM reset line to the frontend reset line.
Signed-off-by: NAndrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

The dvr device could be opened multiple times simultaneously in O_RDONLY mode.
Each open after the first would allocate a new dvr buffer (1880 KB) and leak
the old buffer.  The first close would de-allocate the dvr buffer and cause
all other open dvrs to stop working.  This patch allows only a single O_RDONLY
open of the drv device, as per the API specification.  Multiple O_WRONLY opens
are still allowed and don't appear to cause any problems.
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: NAndrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

This attached patch was originally proposed by Anssi Hannula to the dvb-kernel
user to choose the default broadcast mode when using the ttpci driver.
NTSC users need to only add the following line to modprobe.d:
options dvb-ttpci tv_standard=1 
PAL users will not need to change anything, for this will be the default.
Signed-off-by: NC.Y.M <syphir@syphir.sytes.net>
Signed-off-by: NOliver Endriss <o.endriss@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

This patch fixes a typo in a comment.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NOliver Endriss <o.endriss@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- Issue a warning when more than 80% of the DMA buffer is being used 
  (probably due to bad IRQ latency). Warnings are rate-limited.
- Introduce a new parameter 'bufsize' (in KByte) which increases the
  default DMA buffer of 188 KByte up to 1410 KByte (Activy: 564 KByte).
Signed-off-by: NIngo Schneider <mail@ingo-schneider.de>
Signed-off-by: NOliver Endriss <o.endriss@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- Move documentation for usb v4l devices from
  Documentation/usb to Documentation/video4linux.
- Removed trailing whitespace.
- Update Kconfig help text links to reflect the new file locations.
Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

It should be V4L2_TUNER_MODE_LANG1_LANG2. What the code does is check if 
we are NTSC and a SAP channel is available. If so, then the msp3400 
should switch to standard 0x21 if the user wants to hear the SAP 
channel, which is for audio modes LANG2 (aka SAP) and LANG1_LANG2 
(bilingual).

In the msp3400 driver STEREO is abused for bilingual in PAL. Bilingual 
never worked with NTSC in the past and I decided that I'd better not 
use the bad PAL example.
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- Add support for the uPD64031A NEC Electronics Ghost Reduction i2c device
- Add support for the uPD6408x NEC Electronics 3-Dimensional Y/C separation
  i2c device.
Signed-off-by: NTakahiro Adachi <tadachi@tadachi-net.com>
Signed-off-by: NTakeru Komoriya <komoriya@paken.org>
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- The wait time until the first time the audio mode was detected was
  1+5=6 seconds instead of just 1 second (wrong statement order).
  msp3400c specific bug.
- Implemented audio mode fallback for msp3400c/d just like the msp3400g
  does automatically. E.g. fallback to stereo if no second language exists,
  etc.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

The driver tried to set a register that is not present on msp3400c devices.
Add the missing test.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Add support for the Wolfson Microelectronics WM8739
stereo A/D converter from the ivtv driver.
Many thanks to Takahiro Adachi for writing the original driver.
Signed-off-by: NTakahiro Adachi <tadachi@tadachi-net.com>
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- Fixed PCI ID typo in VIDEO_CX88_ALSA help text
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

- Added firmware download comments to or51211 and or51132 Kconfig help text.
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

There seems to be a new version of the USB DVB-T stick from WideView with a new demod-revision inside and thus a new firwmare.
This patch enables support for that.
Thanks to Mikel Martin for early testing.
Signed-off-by: NPatrick Boettcher <pb@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>