As IO Daisy chain sequence is triggered via hwmod mux, there is no need to
control it from cpuidle path for OMAP3.

Also as omap3_disable_io_chain is no longer being used, just remove the
function.
Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

IO Daisychain feature has to be triggered whenever there is a change in
device's mux configuration (See section 3.9.4 in OMAP4 Public TRM vP).

Now devices can idle independent of the powerdomain, there can be a
window where device is idled and corresponding powerdomain can be
ON/INACTIVE state. In such situations, since both module wake up is
enabled at padlevel as well as io daisychain sequence is triggered,
there will be 2 PRCM interrupts (Module async wake up via swakeup and
IO Pad interrupt). But as PRCM Interrupt handler clears the Module
Padlevel WKST bit in the first interrupt, module specific interrupt
handler will not triggered for the second time

Also look at detailed explanation given by Rajendra at
http://www.spinics.net/lists/linux-serial/msg04480.htmlSigned-off-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: remove dependency on pm.c & pm.h; add kerneldoc]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

Enable IO Wake up for OMAP3/4 as part of PRM Init. Currently this has been
managed in cpuidle path which is not the right place. Subsequent patch
will remove IO Daisy chain handling in cpuidle path once daisy chain is
handled as part of hwmod mux. This patch also moves the OMAP4 IO wakeup
enable code from the trigger function to init time setup.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: harmonize function names with other PRM functions; add
 kerneldoc; resolve checkpatch warnings]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

IO daisychain is a mechanism that allows individual IO pads to generate
wakeup events on their own based on a switch of an input signal level.
This allows the hardware module behind the pad to be powered down, but
still have device level capability to detect IO events, and once this
happens the module can be powered back up to resume IO. See section
3.9.4 in OMAP4430 Public TRM for details.
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
[paul@pwsan.com: use the shared MAX_IOPAD_LATCH_TIME declaration; renamed
 omap4_trigger_io_chain() to conform to other PRM function names;
 added kerneldoc; resolved checkpatch warnings]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

Since IO Daisychain modifies only PRM registers, it makes sense to move
it to PRM File. Also changed the timeout value for IO chain enable to
100us and added a wait for status disable at the end.

Thanks to Nishanth Menon <nm@ti.com> for contributing a fix to the
timeout code waiting for WUCLKOUT to go high.
Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Reviewed-by: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: renamed omap3_trigger_io_chain() to better describe the
 end result and to match other PRM functions; removed
 omap3_disable_io_chain(); moved MAX_IOPAD_LATCH_TIME to prcm-common as it
 will also be used by the OMAP4 code; removed unnecessary barrier;
 added kerneldoc; added credit for fix from Nishanth]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

Currently the enabling and disabling of IO Daisy chain is not
according to the TRM. The below steps are followed to enable/
disable the IO chain, based loosely on the "Sec 3.5.7.2.2
I/O Wake-Up Mechanism" section in OMAP3630 Public TRM[1].

Steps to enable IO chain:
[a] Set PM_WKEN_WKUP.EN_IO bit
[b] Set the PM_WKEN_WKUP.EN_IO_CHAIN bit
[c] Poll for PM_WKST_WKUP.ST_IO_CHAIN.
[d] When ST_IO_CHAIN bit set to 1, clear PM_WKEN_WKUP.EN_IO_CHAIN
[e] Clear ST_IO_CHAIN bit.

Steps to disable IO chain:
[a] Clear PM_WKEN_WKUP.EN_IO_CHAIN bit
[b] Clear PM_WKEN_WKUP.EN_IO bit
[c] Clear PM_WKST_WKUP.ST_IO bit by writing 1 to it.

Step [e] & [c] in each case can be skipped, as these are handled
by the PRCM interrupt handler later.

[1] http://focus.ti.com/pdfs/wtbu/OMAP36xx_ES1.x_PUBLIC_TRM_vV.zipSigned-off-by: Mohan V <mohanv@ti.com>
Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
[paul@pwsan.com: modified commit message to clarify that these steps are
 based loosely on the TRM section, rather than documented exactly]
Reviewed-by: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: resolved new warnings from checkpatch]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

For OMAP4 only builds, the omap2_prm_* functions have dummy wrappers
to detect incorrect usage.  However, several unrelated omap3 PRM
functions have made it inside the #else clause of the #ifdef wrapping
the omap2_prm stubs, causing them to disappear on OMAP4-only builds.

This was unnoticed until the IO chain support was added and introduced
a new function in this section which is referenced by omap_hwmod.c:

arch/arm/mach-omap2/omap_hwmod.c: In function '_reconfigure_io_chain':
arch/arm/mach-omap2/omap_hwmod.c:1665:3: error: implicit declaration of function 'omap3xxx_prm_reconfigure_io_chain' [-Werror=implicit-function-declaration]

Fix by using the #ifdef to only wrap the omap2_prm functions that
need stubs on OMAP4-only builds.

Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
[paul@pwsan.com: fixed checkpatch warnings for patch description]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

Pull btrfs compile warning fixes from Chris Mason.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: cast devid to unsigned long long for printk %llu
  Btrfs: init old_generation in get_old_root

Pull arch/tile update from Chris Metcalf:
 "This one-line bug fix unbreaks glibc robust mutexes (among other
  things no doubt), from code merged in during the 3.5 merge window but
  which we had been running internally at Tilera for almost a year."

* 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: fix bug in get_user() for 4-byte values

Pull fbdev fixes from Florian Tobias Schandinat:

 - two fixes for s3c-fb by Jingoo Han (including a fix for a potential
   division by zero)

 - a couple of randconfig fixes by Arnd Bergmann

 - a cleanup for bfin_adv7393fb by Emil Goode

* tag 'fbdev-fixes-for-3.5-1' of git://github.com/schandinat/linux-2.6:
  video: s3c-fb: fix possible division by zero in s3c_fb_calc_pixclk
  video: s3c-fb: clear SHADOWCON register when clearing hardware window registers
  drivers/tosa: driver needs I2C and SPI to compile
  drivers/savagefb: use mdelay instead of udelay
  video/console: automatically select a font
  video/ili9320: do not mark exported functions __devexit
  drivers/video: use correct __devexit_p annotation
  video: bfin_adv7393fb: Convert to kstrtouint_from_user

The definition of 32-bit values in the 64-bit tilegx architecture is that
they should be sign-extended regardless of whether they are considered
signed or unsigned by the compiler.  Accordingly, we need to use an
"ld4s" rather than "ld4u" to load and sign-extend for get_user().

This fixes glibc bug 14238 (see http://sourceware.org/bugzilla),
introduced during the 3.5 merge window.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

Minchan Kim reports that when a system has many swap areas, and tmpfs
swaps out to the ninth or more, shmem_getpage_gfp()'s attempts to read
back the page cannot locate it, and the read fails with -ENOMEM.

Whoops.  Yes, I blindly followed read_swap_header()'s pte_to_swp_entry(
swp_entry_to_pte()) technique for determining maximum usable swap
offset, without stopping to realize that that actually depends upon the
pte swap encoding shifting swap offset to the higher bits and truncating
it there.  Whereas our radix_tree swap encoding leaves offset in the
lower bits: it's swap "type" (that is, index of swap area) that was
truncated.

Fix it by reducing the SWP_TYPE_SHIFT() in swapops.h, and removing the
broken radix_to_swp_entry(swp_to_radix_entry()) from read_swap_header().

This does not reduce the usable size of a swap area any further, it
leaves it as claimed when making the original commit: no change from 3.0
on x86_64, nor on i386 without PAE; but 3.0's 512GB is reduced to 128GB
per swapfile on i386 with PAE.  It's not a change I would have risked
five years ago, but with x86_64 supported for ten years, I believe it's
appropriate now.

Hmm, and what if some architecture implements its swap pte with offset
encoded below type? That would equally break the maximum usable swap
offset check.  Happily, they all follow the same tradition of encoding
offset above type, but I'll prepare a check on that for next.
Reported-and-Reviewed-and-Tested-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org [3.1, 3.2, 3.3, 3.4]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull SCSI fixes from James Bottomley:
 "This is a couple of minor fixes, one for a preempt warning in the
  mpt2sas driver and one is a config failure with the new sd async
  domain."

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  [SCSI] Fix sd_probe_domain config problem
  [SCSI] mpt2sas: Fix unsafe using smp_processor_id() in preemptible

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

   - Fix a couple of mount regressions due to the recent cleanups.
   - Fix an Oops in the open recovery code
   - Fix an rpc_pipefs upcall hang that results from some of the net
     namespace work from 3.4.x (stable kernel candidate).
   - Fix a couple of write and o_direct regressions that were found at
     last weeks Bakeathon testing event in Ann Arbor."

* tag 'nfs-for-3.5-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: add an endian notation for sparse
  NFSv4.1: integer overflow in decode_cb_sequence_args()
  rpc_pipefs: allow rpc_purge_list to take a NULL waitq pointer
  NFSv4 do not send an empty SETATTR compound
  NFSv2: EOF incorrectly set on short read
  NFS: Use the NFS_DEFAULT_VERSION for v2 and v3 mounts
  NFS: fix directio refcount bug on commit
  NFSv4: Fix unnecessary delegation returns in nfs4_do_open
  NFSv4.1: Convert another trivial printk into a dprintk
  NFS4: Fix open bug when pnfs module blacklisted
  NFS: Remove incorrect BUG_ON in nfs_found_client
  NFS: Map minor mismatch error to protocol not support error.
  NFS: Fix a commit bug
  NFS4: Set parsed mount data version to 4
  NFSv4.1: Ensure we clear session state flags after a session creation
  NFSv4.1: Convert a trivial printk into a dprintk
  NFSv4: Fix up decode_attr_mdsthreshold
  NFSv4: Fix an Oops in the open recovery code
  NFSv4.1: Fix a request leak on the back channel

Pull DMA-mapping fixes from Marek Szyprowski:
 "A set of minor fixes for dma-mapping code (ARM and x86) required for
  Contiguous Memory Allocator (CMA) patches merged in v3.5-rc1."

* 'fixes-for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  x86: dma-mapping: fix broken allocation when dma_mask has been provided
  ARM: dma-mapping: fix debug messages in dmabounce code
  ARM: mm: fix type of the arm_dma_limit global variable
  ARM: dma-mapping: Add missing static storage class specifier

Pull PowerPC fix from Paul Mackerras:
 "Just one commit, and a one-liner at that, but an important one;
  without it hard_irq_disable() does nothing on powerpc."

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
  Make hard_irq_disable() actually hard-disable interrupts

Pull two nfsd bugfixes from J. Bruce Fields.

* 'for-3.5' of git://linux-nfs.org/~bfields/linux:
  nfsd4: BUG_ON(!is_spin_locked()) no good on UP kernels
  NFS: hard-code init_net for NFS callback transports

Merge tag 'stable/for-linus-3.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull five Xen bug-fixes from Konrad Rzeszutek Wilk:

 - When booting as PVHVM we would try to use PV console - but would not validate
   the parameters causing us to crash during restore b/c we re-use the wrong event
   channel.
 - When booting on machines with SR-IOV PCI bridge we didn't check for the bridge
   and tried to use it.
 - Under AMD machines would advertise the APERFMPERF resulting in needless amount
   of MSRs from the guest.
 - A global value (xen_released_pages) was not subtracted at bootup when pages
   were added back in. This resulted in the balloon worker having the wrong
   account of how many pages were truly released.
 - Fix dead-lock when xen-blkfront is run in the same domain as xen-blkback.

* tag 'stable/for-linus-3.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: mark local pages as FOREIGN in the m2p_override
  xen/setup: filter APERFMPERF cpuid feature out
  xen/balloon: Subtract from xen_released_pages the count that is populated.
  xen/pci: Check for PCI bridge before using it.
  xen/events: Add WARN_ON when quick lookup found invalid type.
  xen/hvc: Check HVM_PARAM_CONSOLE_[EVTCHN|PFN] for correctness.
  xen/hvc: Fix error cases around HVM_PARAM_CONSOLE_PFN
  xen/hvc: Collapse error logic.

Pull USB fixes from Greg Kroah-Hartman:
 "Here are a bunch of tiny fixes for the USB core and drivers for
  3.5-rc3

  A bunch of gadget fixes, and new device ids, as well as some fixes for
  a number of different regressions that have been reported recently.
  We also fixed some PCI host controllers to resolve a long-standing bug
  with a whole class of host controllers that have been plaguing people
  for a number of kernel releases, preventing their systems from
  suspending properly.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'usb-3.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (41 commits)
  USB: fix gathering of interface associations
  usb: ehci-sh: fix illegal phy_init() running when platform_data is NULL
  usb: cdc-acm: fix devices not unthrottled on open
  Fix OMAP EHCI suspend/resume failure (i693)
  USB: ohci-hub: Mark ohci_finish_controller_resume() as __maybe_unused
  usb: use usb_serial_put in usb_serial_probe errors
  USB: EHCI: Fix build warning in xilinx ehci driver
  USB: fix PS3 EHCI systems
  xHCI: Increase the timeout for controller save/restore state operation
  xhci: Don't free endpoints in xhci_mem_cleanup()
  xhci: Fix invalid loop check in xhci_free_tt_info()
  xhci: Fix error path return value.
  USB: Checking the wrong variable in usb_disable_lpm()
  usb-storage: Add 090c:1000 to unusal-devs
  USB: serial-generic: use a single set of device IDs
  USB: serial: Enforce USB driver and USB serial driver match
  USB: add NO_D3_DURING_SLEEP flag and revert 151b6128
  USB: option: add more YUGA device ids
  USB: mos7840: Fix compilation of usb serial driver
  USB: option: fix memory leak
  ...

Pull IDE fixes from David S. Miller:

1) Two fixes to icside, one for a build failure and another for a
   warning.  From Christian Dietrich.

2) Fix a bit operation that did erroneous masking, from Julia Lawall.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide:
  drivers/ide/ide-cs.c: adjust suspicious bit operation
  ide: icside.c: fix printk format string compile warning
  ide: icside.c: Fix compile with CONFIG_BLK_DEV_IDEDMA_ICS=n

Avoid warning in 32 bit machines
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Pull sparc update from David S. Miller:
 "This just removes some sparc headers that were never, ever, used."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc: remove two unused headers

gcc was giving an uninit variable warning here.  Strictly
speaking we don't need to init it, but this will make things
much less error prone.
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Pull x86 fixes from Ingo Molnar.

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smp: Fix topology checks on AMD MCM CPUs
  x86/mm: Fix some kernel-doc warnings
  x86, um: Correct syscall table type attributes breaking gcc 4.8

Pull perf fixes from Ingo Molnar.

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  watchdog: Quiet down the boot messages
  perf/x86: Fix broken LBR fixup code
  tracing: Have tracing_off() actually turn tracing off

Pull core updates (RCU and locking) from Ingo Molnar:
 "Most of the diffstat comes from the RCU slow boot regression fixes,
  but there's also a debuggability improvements/fixes."

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  memblock: Document memblock_is_region_{memory,reserved}()
  rcu: Precompute RCU_FAST_NO_HZ timer offsets
  rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure
  rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks
  rcu: RCU_FAST_NO_HZ detection of callback adoption
  spinlock: Indicate that a lockup is only suspected
  kdump: Execute kmsg_dump(KMSG_DUMP_PANIC) after smp_send_stop()
  panic: Make panic_on_oops configurable

Pull target updates from Nicholas Bellinger:
 "This series contains post merge qla_target.c / tcm_qla2xxx bugfixes
  from the past weeks, including the patch to allow target-core to use
  an optional session shutdown callback to help address an active I/O
  shutdown bug in tcm_qla2xxx code (Joern).

  Also included is a target regression bugfix releated to explict ALUA
  target port group CDB emulation that is CC'ed to stable (Roland)."

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  qla2xxx: Remove version.h header file inclusion
  tcm_qla2xxx: Handle malformed wwn strings properly
  tcm_qla2xxx: tcm_qla2xxx_handle_tmr() can be static
  qla2xxx: Don't leak commands we give up on in qlt_do_work()
  qla2xxx: Don't crash if we can't find cmd for failed CTIO
  tcm_qla2xxx: Don't insert nacls without sessions into the btree
  target: Return error to initiator if SET TARGET PORT GROUPS emulation fails
  tcm_qla2xxx: Clear session s_id + loop_id earlier during shutdown
  tcm_qla2xxx: Convert to TFO->put_session() usage
  target: Add TFO->put_session() caller for HW fabric session shutdown

Pull btrfs update from Chris Mason:
 "The dates look like I had to rebase this morning because there was a
  compiler warning for a printk arg that I had missed earlier.

  These are all fixes, including one to prevent using stale pointers for
  device names, and lots of fixes around transaction abort cleanups
  (Josef, Liu Bo).

  Jan Schmidt also sent in a number of fixes for the new reference
  number tracking code.

  Liu Bo beat me to updating the MAINTAINERS file.  Since he thought to
  also fix the git url, I kept his commit."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (24 commits)
  Btrfs: update MAINTAINERS info for BTRFS FILE SYSTEM
  Btrfs: destroy the items of the delayed inodes in error handling routine
  Btrfs: make sure that we've made everything in pinned tree clean
  Btrfs: avoid memory leak of extent state in error handling routine
  Btrfs: do not resize a seeding device
  Btrfs: fix missing inherited flag in rename
  Btrfs: fix incompat flags setting
  Btrfs: fix defrag regression
  Btrfs: call filemap_fdatawrite twice for compression
  Btrfs: keep inode pinned when compressing writes
  Btrfs: implement ->show_devname
  Btrfs: use rcu to protect device->name
  Btrfs: unlock everything properly in the error case for nocow
  Btrfs: fix btrfs_destroy_marked_extents
  Btrfs: abort the transaction if the commit fails
  Btrfs: wake up transaction waiters when aborting a transaction
  Btrfs: fix locking in btrfs_destroy_delayed_refs
  Btrfs: pass locked_page into extent_clear_unlock_delalloc if theres an error
  Btrfs: fix race in tree mod log addition
  Btrfs: add btrfs_next_old_leaf
  ...

Update to the latest btrfs's maintainer mail and git repo.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

the items of the delayed inodes were forgotten to be freed, this patch
fixes it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Since we have two trees for recording pinned extents, we need to go through
both of them to make sure that we've done everything clean.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

We've forgotten to clear extent states in pinned tree, which will results in
space counter mismatch and memory leak:

WARNING: at fs/btrfs/extent-tree.c:7537 btrfs_free_block_groups+0x1f3/0x2e0 [btrfs]()
...
space_info 2 has 8380416 free, is not full
space_info total=12582912, used=4096, pinned=4096, reserved=0, may_use=0, readonly=4194304
btrfs state leak: start 29364224 end 29376511 state 1 in tree ffff880075f20090 refs 1
...
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Seeding devices are not supposed to change any more.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

When we move a file into a directory with compression flag, we need to
inherite BTRFS_INODE_COMPRESS and clear BTRFS_INODE_NOCOMPRESS as well.
But if we move a file into a directory without compression flag, we need
to clear both of them.

It is the way how our setflags deals with compression flag, so keep
the same behaviour here.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

At present, hard_irq_disable() does nothing on powerpc because of
this code in include/linux/interrupt.h:

    #ifndef hard_irq_disable
    #define hard_irq_disable()      do { } while(0)
    #endif

So we need to make our hard_irq_disable be a macro.  It was previously
a macro until commit 7230c564 ("powerpc: Rework lazy-interrupt
handling") changed it to a static inline function.

Cc: stable@vger.kernel.org
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
--
 arch/powerpc/include/asm/hw_irq.h |    3 +++
 1 file changed, 3 insertions(+)

It's a bug, but it happens to work, as BTRFS_COMPRESS_LZO == 2, which
has only one bit set.
Signed-off-by: Li Zefan <lizefan@huawei.com>

If a file has 3 small extents:

| ext1 | ext2 | ext3 |

Running "btrfs fi defrag" will only defrag the last two extents, if those
extent mappings hasn't been read into memory from disk.

This bug was introduced by commit 17ce6ef8
("Btrfs: add a check to decide if we should defrag the range")

The cause is, that commit looked into previous and next extents using
lookup_extent_mapping() only.

While at it, remove the code that checks the previous extent, since
it's sufficient to check the next extent.
Signed-off-by: Li Zefan <lizefan@huawei.com>

I removed this in an earlier commit and I was wrong.  Because compression
can return from filemap_fdatawrite() without having actually set any of it's
pages as writeback() it can make filemap_fdatawait() do essentially nothing,
and then we won't find any ordered extents because they may not have been
created yet.  So not only does this make fsync() completely useless, but it
will also screw up if you truncate on a non-page aligned offset since we
zero out the end and then wait on ordered extents and then call drop caches.
We can drop the cache before the io completes and then we try to unpin the
extent we just wrote we won't find it and everything goes sideways.  So fix
this by putting it back and put a giant comment there to keep me from trying
to remove it in the future.  Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>