ide-cd: convert cdrom_decode_status() to use switch statements

Based on earlier work by Borislav Petkov.

Convert cdrom_decode_status() to use switch statements in
preparation to unify handling of fs and pc requests.

While at it:
- remove superfluous comments and do minor CodingStyle fixups

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide-cd: update debugging support

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
[bart: extracted from "ide-cd: cleanup cdrom_decode_status" patch]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide-cd: respect REQ_QUIET for fs requests in cdrom_decode_status()

There should be no functional change resulting from this patch.

Suggested-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide: remove unused #include <linux/version.h>

Remove unused #include <linux/version.h> in drivers/ide/at91_ide.c.

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

tx4939ide: Fix tx4939ide_{in,out}put_data_swap argument

The commit adb1af9 ("ide: pass command instead of request to
ide_pio_datablock()") missed tx4939ide driver.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

tx493[89]ide: Remove big endian version of tx493[89]ide_tf_{load,read}

Now tx493[89]ide_tf_{load,read} do not contain word I/O operations.
They are endian-free now.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>,
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide-cd: carve out an ide_cd_breathe()-helper for fs write requests

There should be no functional change resulting from this patch.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide-cd: move status checking into the IRQ handler

There should be no functional change resulting from this patch.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide-h8300: remove custom tf_{read|load}() methods

Since tf_{read|load}() methods of this driver have now become identical to their
standard counterparts using I/O port accesses, there's no need to override those
anymore...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

at91_ide: remove custom tf_{read|load}() methods

Since tf_{read|load}() methods of this driver have now become identical to their
standard counterparts using MMIO accesses, there's no need to override those
anymore...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide-h8300: remove mm_{inw|outw}()

Remove two no longer used functions that I've overlooked...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

tx4939ide: remove wmb()

* define CHECK_DMA_MASK
* remove use of wmb()

Reported-by: Grant Grundler <grundler@google.com>
Reviewed-by: Grant Grundler <grundler@google.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>

ide: remove wmb() from ide-dma-sff.c and scc_pata.c

This patch:
o replaces "mask" variable in ide_dma_end() with #define.
o removes use of wmb() in ide-dma-sff.c and scc_pata.c.
o is not tested - I don't have (or want) the HW.

Signed-off-by: Grant Grundler <grundler@google.com>
Cc: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide: falconide/q40ide - Use __ide_mm_{in,out}sw() for data

Both of commits f94116aeec7a299640dd692128e1d22178affa8d ("ide: cleanup
<asm-m68k/ide.h>") and 15a453a955f89f6545118770c669b52e925368bd ("ide: include
<asm/ide.h> only when needed") break falconide:

| Uniform Multi-Platform E-IDE driver
| ide: Falcon IDE controller
| Probing IDE interface ide0...
| hda: Sarge m68k, ATA DISK drive
| ide0 at 0xfff00000 on irq 15 (serialized)
| ide-gd driver 1.18
| hda: max request size: 128KiB
| hda: 2118816 sectors (1084 MB) w/256KiB Cache, CHS=2102/16/63
|  hda:<4>hda: lost interrupt

This happens because falconide relies on {in,out}sw() being redefined in
<asm/ide.h>, as included by <linux/ide.h>, which is no longer the case.
Use __ide_mm_{in,out}sw() from <asm/ide.h> instead, just like
ide_{in,out}put_data() do.

The same problem seems to exist in q40ide.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

ide: Fix host drivers that need IRQF_SHARED

commit 255115fb35f80735c21a1cbe9809e9795a3af26e ("ide: allow host drivers to
specify IRQ flags") added irq_flags fields to struct ide_port_info and struct
ide_host.  Drivers can now set ide_port_info.irq_flags = IRQF_SHARED, while
init_irq() passes ide_host.irq_flags to request_irq().

Unfortunately ide_host.irq_flags is never set, causing (on ARAnyM):

| Uniform Multi-Platform E-IDE driver
| ide: Falcon IDE controller
| Probing IDE interface ide0...
| hda: Sarge m68k, ATA DISK drive
| init_irq: sa = 0
| ide0: disabled, unable to get IRQ 15
| ide0: failed to initialize IDE interface
| ide0: disabling port

Solve this by copying ide_port_info.irq_flags to ide_host.irq_flags in
ide_host_alloc().

This bug probably affects the following IDE host drivers:
  - buddha
  - delkin_cb
  - falconide
  - gayle
  - ide-cs
  - macide
  - q40ide
  - scc_pata
  - sgiioc4

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Linux 2.6.30-rc1

Merge branch 'core/softlockup' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'core/softlockup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  softlockup: make DETECT_HUNG_TASK default depend on DETECT_SOFTLOCKUP
  softlockup: move 'one' to the softlockup section in sysctl.c
  softlockup: ensure the task has been switched out once
  softlockup: remove timestamp checking from hung_task
  softlockup: convert read_lock in hung_task to rcu_read_lock
  softlockup: check all tasks in hung_task
  softlockup: remove unused definition for spawn_softlockup_task
  softlockup: fix potential race in hung_task when resetting timeout
  softlockup: fix to allow compiling with !DETECT_HUNG_TASK
  softlockup: decouple hung tasks check from softlockup detection

Merge branch 'tracing-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y
  branch tracer: Fix for enabling branch profiling makes sparse unusable
  ftrace: Correct a text align for event format output
  Update /debug/tracing/README
  tracing/ftrace: alloc the started cpumask for the trace file
  tracing, x86: remove duplicated #include
  ftrace: Add check of sched_stopped for probe_sched_wakeup
  function-graph: add proper initialization for init task
  tracing/ftrace: fix missing include string.h
  tracing: fix incorrect return type of ns2usecs()
  tracing: remove CALLER_ADDR2 from wakeup tracer
  blktrace: fix pdu_len when tracing packet command requests
  blktrace: small cleanup in blk_msg_write()
  blktrace: NUL-terminate user space messages
  tracing: move scripts/trace/power.pl to scripts/tracing/power.pl

Merge branch 'irq/threaded' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'irq/threaded' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: fix devres.o build for GENERIC_HARDIRQS=n
  genirq: provide old request_irq() for CONFIG_GENERIC_HARDIRQ=n
  genirq: threaded irq handlers review fixups
  genirq: add support for threaded interrupts to devres
  genirq: add threaded interrupt handler support

NFS: Fix the return value in nfs_page_mkwrite()

Commit c2ec175c39f62949438354f603f4aa170846aabb ("mm: page_mkwrite
change prototype to match fault") exposed a bug in the NFS
implementation of page_mkwrite.  We should be returning 0 on success...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'for-linus' of git://git./linux/kernel/git/jbarnes/pci-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  PCI: pci_slot: grab refcount on slot's bus
  PCI Hotplug: acpiphp: grab refcount on p2p subordinate bus
  PCI: allow PCI core hotplug to remove PCI root bus
  PCI: Fix oops in pci_vpd_truncate
  PCI: don't corrupt enable_cnt when doing manual resource alignment
  PCI: annotate pci_rescan_bus as __ref, not __devinit
  PCI-IOV: fix missing kernel-doc
  PCI: Setup disabled bridges even if buses are added
  PCI: SR-IOV quirk for Intel 82576 NIC

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  loop: mutex already unlocked in loop_clr_fd()
  cfq-iosched: don't let idling interfere with plugging
  block: remove unused REQ_UNPLUG
  cfq-iosched: kill two unused cfqq flags
  cfq-iosched: change dispatch logic to deal with single requests at the time
  mflash: initial support
  cciss: change to discover first memory BAR
  cciss: kernel scan thread for MSA2012
  cciss: fix residual count for block pc requests
  block: fix inconsistency in I/O stat accounting code
  block: elevator quiescing helpers

Fix build errors due to CONFIG_BRANCH_TRACER=y

The code that enables branch tracing for all (non-constant) branches
plays games with the preprocessor and #define's the C 'if ()' construct
to do tracing.

That's all fine, but it fails for some unusual but valid C code that is
sometimes used in macros, notably by the intel-iommu code:

if (i=drhd->iommu, drhd->ignored) ..

because now the preprocessor complains about multiple arguments to the
'if' macro.

So make the macro expansion of this particularly horrid trick use
varargs, and handle the case of comma-expressions in if-statements.  Use
another macro to do it cleanly in just one place.

This replaces a patch by David (and acked by Steven) that did this all
inside that one already-too-horrid macro.

Tested-by: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'for-2.6.30' of git://git./linux/kernel/git/broonie/sound-2.6

* 'for-2.6.30' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound-2.6:
  ASoC: TWL4030: Compillation error fix

Merge branch 'for-linus' of git://git./linux/kernel/git/tiwai/sound-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6: (36 commits)
  ALSA: hda - Add VREF powerdown sequence for another board
  ALSA: oss - volume control for CSWITCH and CROUTE
  ALSA: hda - add missing comma in ad1884_slave_vols
  sound: usb-audio: allow period sizes less than 1 ms
  sound: usb-audio: save data packet interval in audioformat structure
  sound: usb-audio: remove check_hw_params_convention()
  sound: usb-audio: show sample format width in proc file
  ASoC: fsl_dma: Pass the proper device for dma mapping routines
  ASoC: Fix null dereference in ak4535_remove()
  ALSA: hda - enable SPDIF output for Intel DX58SO board
  ALSA: snd-atmel-abdac: increase periods_min to 6 instead of 4
  ALSA: snd-atmel-abdac: replace bus_id with dev_name()
  ALSA: snd-atmel-ac97c: replace bus_id with dev_name()
  ALSA: snd-atmel-ac97c: cleanup registers when removing driver
  ALSA: snd-atmel-ac97c: do a proper reset of the external codec
  ALSA: snd-atmel-ac97c: enable interrupts to catch events for error reporting
  ALSA: snd-atmel-ac97c: set correct size for buffer hardware parameter
  ALSA: snd-atmel-ac97c: do not overwrite OCA and ICA when assigning channels
  ALSA: snd-atmel-ac97c: remove dead break statements after return in switch case
  ALSA: snd-atmel-ac97c: cleanup register definitions
  ...

Merge branch 'upstream-linus' of git://git./linux/kernel/git/jgarzik/libata-dev

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  sata_mv: shorten register names
  sata_mv: workaround errata SATA#13
  sata_mv: cosmetic renames
  sata_mv: workaround errata SATA#26
  sata_mv: workaround errata PCI#7
  sata_mv: replace 0x1f with ATA_PIO4 (v2)
  sata_mv: fix irq mask races
  sata_mv: revert SoC irq breakage
  libata: ahci enclosure management bios workaround
  ata: Add TRIM infrastructure
  ata_piix: VGN-BX297XP wants the controller power up on suspend
  libata: Remove some redundant casts from pata_octeon_cf.c
  pata_artop: typo

Merge branch 'i2c-for-2630-v2' of git://aeryn.fluff.org.uk/bjdooks/linux

* 'i2c-for-2630-v2' of git://aeryn.fluff.org.uk/bjdooks/linux:
  i2c: imx: Make disable_delay a per-device variable
  i2c: xtensa s6000 i2c driver
  powerpc/85xx: i2c-mpc: use new I2C bindings for the Socates board
  i2c: i2c-mpc: make I2C bus speed configurable
  i2c: i2c-mpc: use dev based printout function
  i2c: i2c-mpc: various coding style fixes
  i2c: imx: Add missing request_mem_region in probe()
  i2c: i2c-s3c2410: Initialise Samsung I2C controller early
  i2c-s3c2410: Simplify bus frequency calculation
  i2c-s3c2410: sda_delay should be in ns, not clock ticks
  i2c: iMX/MXC support

Merge branch 'hwmon-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6

* 'hwmon-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6:
  hwmon: Add Asus ATK0110 support
  hwmon: (lm95241) Convert to new-style i2c driver

parport: Use the PCI IRQ if offered

PCI parallel port devices can IRQ share so we should stop them hogging
the line and making a mess on modern PC systems.  We know the sharing
side works as the PCMCIA driver has shared the parallel port IRQ for
some time.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tty: jsm cleanups

Here are some cleanups, mainly removing unused variables and silly
declarations.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Adjust path to gpio headers

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KGDB_SERIAL_CONSOLE check for module

Depend on KGDB_SERIAL_CONSOLE being set to N rather than !Y, since it can
be built as a module.

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change KCONFIG name

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tty: Blackin CTS/RTS

Both software emulated and hardware based CTS and RTS are enabled in
serial driver.

The CTS RTS PIN connection on BF548 UART port is defined as a modem
device not as a host device.  In order to test it under Linux, please
nake a cross UART cable to exchange CTS and RTS signal.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change hardware flow control from poll to interrupt driven

Only the CTS bit is affected.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add support for the MAX3100 SPI UART.

(akpm: queued pending confirmation of the new major number)

[randy.dunlap@oracle.com: select SERIAL_CORE]
Signed-off-by: Christian Pellegrin <chripell@fsfe.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lanana: assign a device name and numbering for MAX3100

This is a low density serial port so needs a real major/minor

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

serqt: initial clean up pass for tty side

Avoid using port->tty where possible (makes refcount fixing easier
later).

Remove unused code (the ioctl path is not used if the device has
mget/mset functions)

Remove various un-needed typecasts and long names so it could read it to
do the changes.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tty: Use the generic RS485 ioctl on CRIS

Use the new general RS485 Linux data structure (introduced by Alan with
commit number c26c56c0f40e200e61d1390629c806f6adaffbcc) in the Cris
architecture too (currently, Cris still uses the old private data
structure instead of the new one).

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Tested-by: Hinko Kocevar <hinko.kocevar@cetrtapot.si>
Tested-by: Janez Cufer <janez.cufer@cetrtapot.si>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tty: Correct inline types for tty_driver_kref_get()

tty_driver_kref_get() should be static inline and not extern inline
(the latter even changed it's semantics in gcc >= 4.3).

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

splice: fix deadlock in splicing to file

There's a possible deadlock in generic_file_splice_write(),
splice_from_pipe() and ocfs2_file_splice_write():

 - task A calls generic_file_splice_write()
 - this calls inode_double_lock(), which locks i_mutex on both
   pipe->inode and target inode
 - ordering depends on inode pointers, can happen that pipe->inode is
   locked first
 - __splice_from_pipe() needs more data, calls pipe_wait()
 - this releases lock on pipe->inode, goes to interruptible sleep
 - task B calls generic_file_splice_write(), similarly to the first
 - this locks pipe->inode, then tries to lock inode, but that is
   already held by task A
 - task A is interrupted, it tries to lock pipe->inode, but fails, as
   it is already held by task B
 - ABBA deadlock

Fix this by explicitly ordering locks: the outer lock must be on
target inode and the inner lock (which is later unlocked and relocked)
must be on pipe->inode.  This is OK, pipe inodes and target inodes
form two nonoverlapping sets, generic_file_splice_write() and friends
are not called with a target which is a pipe.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: support nanosecond timestamp

After a review of user's feedback for finding out other compatibility
issues, I found nilfs improperly initializes timestamps in inode;
CURRENT_TIME was used there instead of CURRENT_TIME_SEC even though nilfs
didn't have nanosecond timestamps on disk.  A few users gave us the report
that the tar program sometimes failed to expand symbolic links on nilfs,
and it turned out to be the cause.

Instead of applying the above displacement, I've decided to support
nanosecond timestamps on this occation.  Fortunetaly, a needless 64-bit
field was in the nilfs_inode struct, and I found it's available for this
purpose without impact for the users.

So, this will do the enhancement and resolve the tar problem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: introduce secondary super block

The former versions didn't have extra super blocks.  This improves the
weak point by introducing another super block at unused region in tail of
the partition.

This doesn't break disk format compatibility; older versions just ingore
the secondary super block, and new versions just recover it if it doesn't
exist.  The partition created by an old mkfs may not have unused region,
but in that case, the secondary super block will not be added.

This doesn't make more redundant copies of the super block; it is a future
work.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: simplify handling of active state of segments

will reduce some lines of segment constructor.  Previously, the state was
complexly controlled through a list of segments in order to keep
consistency in meta data of usage state of segments.  Instead, this
presents ``calculated'' active flags to userland cleaner program and stop
maintaining its real flag on disk.

Only by this fake flag, the cleaner cannot exactly know if each segment is
reclaimable or not.  However, the recent extension of nilfs_sustat ioctl
struct (nilfs2-extend-nilfs_sustat-ioctl-struct.patch) can prevent the
cleaner from reclaiming in-use segment wrongly.

So, now I can apply this for simplification.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: mark minor flag for checkpoint created by internal operation

Nilfs creates checkpoints even for garbage collection or metadata updates
such as checkpoint mode change.  So, user often sees checkpoints created
only by such internal operations.

This is inconvenient in some situations.  For example, application that
monitors checkpoints and changes them to snapshots, will fall into an
infinite loop because it cannot distinguish internally created
checkpoints.

This patch solves this sort of problem by adding a flag to checkpoint for
identification.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: clean up sketch file

The sketch file is a file to mark checkpoints with user data.  It was
experimentally introduced in the original implementation, and now
obsolete.  The file was handled differently with regular files; the file
size got truncated when a checkpoint was created.

This stops the special treatment and will treat it as a regular file.
Most users are not affected because mkfs.nilfs2 no longer makes this file.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: super block operations fix endian bug

This adds a missing endian conversion of checksum field in the super
block.  This fixes compatibility issue on big endian machines which will
come to surface after supporting recovery of super block.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: replace BUG_ON and BUG calls triggerable from ioctl

Pekka Enberg advised me:
> It would be nice if BUG(), BUG_ON(), and panic() calls would be
> converted to proper error handling using WARN_ON() calls. The BUG()
> call in nilfs_cpfile_delete_checkpoints(), for example, looks to be
> triggerable from user-space via the ioctl() system call.

This will follow the comment and keep them to a minimum.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: extend nilfs_sustat ioctl struct

This adds a new argument to the nilfs_sustat structure.

The extended field allows to delete volatile active state of segments,
which was needed to protect freshly-created segments from garbage
collection but has confused code dealing with segments.  This
extension alleviates the mess and gives room for further
simplifications.

The volatile active flag is not persistent, so it's eliminable on this
occasion without affecting compatibility other than the ioctl change.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: use unlocked_ioctl

Pekka Enberg suggested converting ->ioctl operations to use
->unlocked_ioctl to avoid BKL.

The conversion was verified to be safe, so I will take it on this
occasion.

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: remove compat ioctl code

This removes compat code from the nilfs ioctls and applies the same
function for both .ioctl and .compat_ioctl file operations.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: use fixed sized types for ioctl structures

Nilfs ioctl had structures not having fixed sized types such as:

  struct nilfs_argv {
         void *v_base;
         size_t v_nmembs;
         size_t v_size;
         int v_index;
         int v_flags;
  };

Further, some of them are wrongly aligned:

  e.g.

  struct nilfs_cpmode {
        __u64 cm_cno;
        int cm_mode;
  };

The size of wrongly aligned structures varies depending on
architectures, and it breaks the identity of ioctl commands, which
leads to arch dependent errors.

Previously, these are compensated by using compat_ioctl.

This fixes these problems and allows removal of compat ioctl.

Since this will change sizes of those structures, binary compatibility
for the past utilities will once break; new utilities have to be used
instead.  However, it would be helpful to avoid platform dependent
problems in the long term.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: remove timedwait ioctl command

This removes NILFS_IOCTL_TIMEDWAIT command from ioctl interface along
with the related flags and wait queue.

The command is terrible because it just sleeps in the ioctl.  I prefer
to avoid this by devising means of event polling in userland program.
By reconsidering the userland GC daemon, I found this is possible
without changing behaviour of the daemon and sacrificing efficiency.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix buggy behavior seen in enumerating checkpoints

This will fix the weird behavior of lscp command in listing continuously
created checkpoints; the output of lscp is rewinded regularly for the
recent nilfs.  As a result of debugging, a defect was found in
nilfs_cpfile_do_get_cpinfo() function.

Though the function can be repeatedly called to enumerate checkpoints and
it can skip invalid checkpoint entries, the index value was not carried
between successive calls.

The bug has long been present, and came to surface after applying a bugfix
nilfs2-fix-problems-of-memory-allocation-in-ioctl.patch, which increased
frequency of calling the function.  The similar bugfix was already applied
for ``snapshots'' by
nilfs2-fix-gc-failure-on-volumes-keeping-numerous-snapshots.patch.

This fixes the problem by making the index argument bidirectional on the
function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: clean up indirect function calling conventions

This cleans up the strange indirect function calling convention used in
nilfs to follow the normal kernel coding style.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix improper return values of nilfs_get_cpinfo ioctl

A few tool developers gave me requests for fixing inconvenient return
value of nilfs_get_cpinfo() ioctl; if the requested mode is NILFS_SNAPSHOT
and the specified start entry is not a snapshot, the ioctl unnaturally
returns one as the number of acquired snapshot item.

In addition, the ioctl function returns an ENOENT error for checkpoints
within blocks deleted by garbage collection.

These behaviors require corrections for programs which enumerate
snapshots.  This resolves the inconvenience by changing the return values
to zero for the above cases.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix gc failure on volumes keeping numerous snapshots

This resolves the following failure of nilfs2 cleaner daemon:

 nilfs_cleanerd[20670]: cannot clean segments: No such file or directory
 nilfs_cleanerd[20670]: shutdown

When creating thousands of snapshots, the cleaner daemon had rarely died
as above due to an error returned from the kernel code.

After applying the recent patch which fixed memory allocation problems in
ioctl (Message-Id: <20081215.155840.105124170.ryusuke@osrg.net>), the
problem gets more frequent.

It turned out to be a bug of nilfs_ioctl_wrap_copy function and one of its
callback routines to read out information of snapshots; if the
nilfs_ioctl_wrap_copy function divided a large read request into multiple
requests, the second and later requests have failed since a restart
position on snapshot meta data was not properly set forward.

It's a deficiency of the callback interface that cannot pass the restart
position among multiple requests.  This patch fixes the issue by allowing
nilfs_ioctl_wrap_copy and snapshot read functions to exchange a position
argument.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add maintainer

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: insert explanations in gcinode file

The file gcinode.c gives buffer cache functions for on-disk blocks
moved in garbage collection.  Joern Engel has suggested inserting its
explanations in the source file (Message-ID:
<20080917144146.GD8750@logfs.org> and
<20080917224953.GB14644@logfs.org>).

This follows the comment.

Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: avoid double error caused by nilfs_transaction_end

Pekka Enberg pointed out that double error handlings found after
nilfs_transaction_end() can be avoided by separating abort operation:

 OK, I don't understand this. The only way nilfs_transaction_end() can
 fail is if we have NILFS_TI_SYNC set and we fail to construct the
 segment. But why do we want to construct a segment if we don't commit?

 I guess what I'm asking is why don't we have a separate
 nilfs_transaction_abort() function that can't fail for the erroneous
 case to avoid this double error value tracking thing?

This does the separation and renames nilfs_transaction_end() to
nilfs_transaction_commit() for clarification.

Since, some calls of these functions were used just for exclusion control
against the segment constructor, they are replaced with semaphore
operations.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: cleanup nilfs_clear_inode

This will remove the following unnecessary locks and cleanup code in
nilfs_clear_inode():

- unnecessary protection using nilfs_transaction_begin() and
  nilfs_transaction_end().

- cleanup code of i_dirty list field which is never chained
  when this function is called.

- spinlock used when releasing i_bh field.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix problems of memory allocation in ioctl

This is another patch for fixing the following problems of a memory
copy function in nilfs2 ioctl:

(1) It tries to allocate 128KB size of memory even for small objects.

(2) Though the function repeatedly tries large memory allocations
    while reducing the size, GFP_NOWAIT flag is not specified.
    This increases the possibility of system memory shortage.

(3) During the retries of (2), verbose warnings are printed
    because _GFP_NOWARN flag is not used for the kmalloc calls.

The first patch was still doing large allocations by kmalloc which are
repeatedly tried while reducing the size.

Andi Kleen told me that using copy_from_user for large memory is not
good from the viewpoint of preempt latency:

 On Fri, 12 Dec 2008 21:24:11 +0100, Andi Kleen <andi@firstfloor.org> wrote:
 > > In the current interface, each data item is copied twice: one is to
 > > the allocated memory from user space (via copy_from_user), and another
 >
 > For such large copies it is better to use multiple smaller (e.g. 4K)
 > copy user, that gives better real time preempt latencies. Each cfu has a
 > cond_resched(), but only one, not multiple times in the inner loop.

He also advised me that:

 On Sun, 14 Dec 2008 16:13:27 +0100, Andi Kleen <andi@firstfloor.org> wrote:
 > Better would be if you could go to PAGE_SIZE. order 0 allocations
 > are typically the fastest / least likely to stall.
 >
 > Also in this case it's a good idea to use __get_free_pages()
 > directly, kmalloc tends to be become less efficient at larger
 > sizes.

For the function in question, the size of buffer memory can be reduced
since the buffer is repeatedly used for a number of small objects.  On
the other hand, it may incur large preempt latencies for larger buffer
because a copy_from_user (and a copy_to_user) was applied only once
each cycle.

With that, this revision uses the order 0 allocations with
__get_free_pages() to fix the original problems.

Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: update makefile and Kconfig

This adds a Makefile for the nilfs2 file system, and updates the
makefile and Kconfig file in the file system directory.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: ioctl operations

This adds userland interface implemented with ioctl.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: block cache for garbage collection

This adds the cache of on-disk blocks to be moved in garbage
collection.  The disk blocks are held with dummy inodes (called
gcinodes), and this file provides lookup function of the dummy inodes,
and their buffer read function.

Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: another dat for garbage collection

NILFS2 uses another DAT inode during garbage collection to ensure
atomicity and consistency of the DAT in the transient state.  This
twin inode is called GCDAT.

This adds functions to initialize the GCDAT and to switch page caches
and B-tree node caches between these two inodes.

Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: recovery functions

This adds recovery function on mount.

Usually the recovery is achieved by just finding the latest super
root.  When logs without checkpoints were appended for data sync
operations after the latest super root, the recovery function will
perform roll forwarding and reconstruct new log(s) with a super root.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix missed-sync issue for do_sync_mapping_range()

Chris Mason pointed out that there is a missed sync issue in
nilfs_writepages():

On Wed, 17 Dec 2008 21:52:55 -0500, Chris Mason wrote:
> It looks like nilfs_writepage ignores WB_SYNC_NONE, which is used by
> do_sync_mapping_range().

where WB_SYNC_NONE in do_sync_mapping_range() was replaced with
WB_SYNC_ALL by Nick's patch (commit:
ee53a891f47444c53318b98dac947ede963db400).

This fixes the problem by letting nilfs_writepages() write out the log of
file data within the range if sync_mode is WB_SYNC_ALL.

This involves removal of nilfs_file_aio_write() which was previously
needed to ensure O_SYNC sync writes.

Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: segment constructor

This adds the segment constructor (also called log writer).

The segment constructor collects dirty buffers for every dirty inode,
makes summaries of the buffers, assigns disk block addresses to the
buffers, and then submits BIOs for the buffers.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: segment buffer

This adds the segment buffer which is used to constuct logs.

[akpm@linux-foundation.org: BIO_RW_SYNC got removed]
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: super block operations

This adds super block operations for the nilfs2 file system.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: operations for the_nilfs core object

This adds functions on the_nilfs object, which keeps shared resources and
states among a read/write mount and snapshots mounts going individually.

the_nilfs is allocated per block device; it is created when user first
mount a snapshot or a read/write mount on the device, then it is reused
for successive mounts.  It will be freed when all mount instances on the
device are detached.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: pathname operations

This adds pathname operations, most of which comes from the ext2 file
system.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: directory entry operations

This adds directory handling functions, most of which comes from the ext2
file system.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: file operations

This adds primitives for regular file handling.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: inode operations

This adds inode level operations of the nilfs2 file system.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: segment usage file

This adds a meta data file which stores the allocation state of segments.

[konishi.ryusuke@lab.ntt.co.jp: fix wrong counting of checkpoints and dirty segments]
Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: checkpoint file

This adds a meta data file which holds checkpoint entries in its data
blocks.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: inode map file

This adds a meta data file which stores on-disk inodes in its data blocks.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: disk address translator

This adds the disk address translation file (DAT) whose primary function
is to convert virtual disk block numbers to actual disk block numbers.

The virtual block numbers of NILFS are associated with checkpoint
generation numbers, and this file also provides functions to manage the
lifetime information of each virtual block number.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: persistent object allocator

This adds common functions to allocate or deallocate entries with bitmaps
on a meta data file.  This feature is used by the DAT and ifile.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: meta data file

This adds the meta data file, which serves common buffer functions to the
DAT, sufile, cpfile, ifile, and so forth.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: buffer and page operations

This adds common routines for buffer/page operations used in B-tree
node caches, meta data files, or segment constructor (log writer).

NILFS uses copy functions for buffers and pages due to the following
reasons:

 1) Relocation required for COW
    Since NILFS changes address of on-disk blocks, moving buffers
    in page cache is needed for the buffers which are not addressed
    by a file offset.  If buffer size is smaller than page size,
    this involves partial copy of pages.

 2) Freezing mmapped pages
    NILFS calculates checksums for each log to ensure its validity.
    If page data changes after the checksum calculation, this validity
    check will not work correctly.  To avoid this failure for mmaped
    pages, NILFS freezes their data by copying.

 3) Copy-on-write for DAT pages
    NILFS makes clones of DAT page caches in a copy-on-write manner
    during GC processes, and this ensures atomicity and consistency
    of the DAT in the transient state.

In addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty()
and nilfs_clear_page_dirty() respectively.

* nilfs_mark_buffer_dirty() was required to avoid NULL pointer
  dereference faults:

  Since the page cache of B-tree node pages or data page cache of pseudo
  inodes does not have a valid mapping->host, calling mark_buffer_dirty()
  for their buffers causes the fault; it calls __mark_inode_dirty(NULL)
  through __set_page_dirty().

* nilfs_clear_page_dirty() was needed in the two cases:

 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
    page dirty flags when it copies back pages from the cloned cache
    (gcdat->{i_mapping,i_btnode_cache}) to its original cache
    (dat->{i_mapping,i_btnode_cache}).

 2) Some B-tree operations like insertion or deletion may dispose buffers
    in dirty state, and this needs to cancel the dirty state of their
    pages.  clear_page_dirty_for_io() caused faults because it does not
    clear the dirty tag on the page cache.

Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: B-tree node cache

This adds routines for B-tree node buffers.

Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: direct block mapping

This adds block mappings using direct pointers which are stored in the
i_bmap array of inode.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: B-tree based block mapping

This adds declarations and functions of NILFS2 B-tree.

Two variants are integrated in the NILFS2 B-tree.  The B-tree for the most
files points to the child nodes or data blocks with virtual block
addresses, whereas the B-tree of the DAT uses actual block addresses.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: integrated block mapping

This adds structures and operations for the block mapping (bmap for
short).  NILFS2 uses direct mappings for short files or B-tree based
mappings for longer files.

Every on-disk data block is held with inodes and managed through this
block mapping.  The nilfs_bmap structure and a set of functions here
provide this capability to the NILFS2 inode.

[penberg@cs.helsinki.fi: remove a bunch of bmap wrapper macros]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add inode and other major structures

This adds the following common structures of the NILFS2 file system.

* nilfs_inode_info structure:
  gives on-memory inode.

* nilfs_sb_info structure:
  keeps per-mount state and a special inode for the ifile.
  This structure is attached to the super_block structure.

* the_nilfs structure:
  keeps shared state and locks among a read/write mount and snapshot
  mounts.  This keeps special inodes for the sufile, cpfile, dat, and
  another dat inode used during GC (gcdat).  This also has a hash table
  of dummy inodes to cache disk blocks during GC (gcinodes).

* nilfs_transaction_info structure:
  keeps per task state while nilfs is writing logs or doing indivisible
  inode or namespace operations.  This structure is used to identify
  context during log making and store nest level of the lock which
  ensures atomicity of file system operations.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: disk format and userland interface

This adds a header file which specifies the on-disk format and ioctl
interface of the nilfs2 file system.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add document

This adds a document describing the features, mount options, userland
tools, usage, disk format, and related URLs for the nilfs2 file system.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: update the old macro DMA_nBIT_MASK related documentations

Update the old macro DMA_nBIT_MASK related documentations

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_24BIT_MASK macro with DMA_BIT_MASK(24)

Replace all DMA_24BIT_MASK macro with DMA_BIT_MASK(24)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_28BIT_MASK macro with DMA_BIT_MASK(28)

Replace all DMA_28BIT_MASK macro with DMA_BIT_MASK(28)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_30BIT_MASK macro with DMA_BIT_MASK(30)

Replace all DMA_30BIT_MASK macro with DMA_BIT_MASK(30)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_31BIT_MASK macro with DMA_BIT_MASK(31)

Replace all DMA_31BIT_MASK macro with DMA_BIT_MASK(31)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_32BIT_MASK macro with DMA_BIT_MASK(32)

Replace all DMA_32BIT_MASK macro with DMA_BIT_MASK(32)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_39BIT_MASK macro with DMA_BIT_MASK(39)

Replace all DMA_39BIT_MASK macro with DMA_BIT_MASK(39)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_40BIT_MASK macro with DMA_BIT_MASK(40)

Replace all DMA_40BIT_MASK macro with DMA_BIT_MASK(40)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_48BIT_MASK macro with DMA_BIT_MASK(48)

Replace all DMA_48BIT_MASK macro with DMA_BIT_MASK(48)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dma-mapping: replace all DMA_64BIT_MASK macro with DMA_BIT_MASK(64)

Replace all DMA_64BIT_MASK macro with DMA_BIT_MASK(64)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>