Fix a bug in

    commit ba0a6c9f
    Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
    AuthorDate: Wed Sep 23 15:57:03 2009 -0700
    Commit:     Linus Torvalds <torvalds@linux-foundation.org>
    CommitDate: Thu Sep 24 07:21:01 2009 -0700

        fcntl: add F_[SG]ETOWN_EX

In asm-generic/fcntl.h, F_SETOWN_EX and F_GETLK64 both have value 12, and
F_GETOWN_EX and F_SETLK64 both have value 13.
Reported-by: N"Joseph S. Myers" <joseph@codesourcery.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Andreas Schwab <schwab@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NUlrich Drepper <drepper@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Lee Schermerhorn reported that he saw bad pointer dereference in
mem_cgroup_end_migration() when he disabled memcg by boot option.

memcg's page migration logic works as

	mem_cgroup_prepare_migration(page, &ptr);
	do page migration
	mem_cgroup_end_migration(page, ptr);

Now, ptr is not initialized in prepare_migration when memcg is disabled
by boot option. This causes panic in end_migration. This patch fixes it.
Reported-by: NLee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix wrong bit mask for blanking register.  Due to the error a CRT monitor
blanks off due to wrong frequency (out of range) instead of PM signal
(vertical and horizontal frequencies cut off).

Just compare the mask with bits set in the switch(blank) clause below the
changed line.
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove fb_save_state() and fb_restore_state operations from frame buffer layer.
They are used only in two drivers:
1. savagefb  - and cause bug #11248
2. uvesafb

Usage of these operations is misunderstood in both drivers so kill these
operations, fix the bug #11248 and avoid confusion in the future.

Tested on Savage 3D/MV card and the patch fixes the bug #11248.

The frame buffer layer uses these funtions during switch between graphics
and text mode of the console, but these drivers saves state before
switching of the frame buffer (in the fb_open) and after releasing it (in
the fb_release).  This defeats the purpose of these operations.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11248Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Reported-by: NJochen Hein <jochen@jochen.org>
Tested-by: NJochen Hein <jochen@jochen.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Januszewski <spock@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 341ce06f ("page allocator:
calculate the alloc_flags for allocation only once") altered watermark
logic slightly by allowing rt_tasks that are handling an interrupt to set
ALLOC_HARDER.  This patch brings the watermark logic more in line with
2.6.30.

This change results in a reduction of the number high-order GFP_ATOMIC
allocation failures reported.  See
http://www.gossamer-threads.com/lists/linux/kernel/1144153

[rientjes@google.com: Spotted the problem]
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: NRik van Riel <riel@redhat.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

page allocator: always wake kswapd when restarting an allocation attempt after direct reclaim failed

If a direct reclaim makes no forward progress, it considers whether it
should go OOM or not.  Whether OOM is triggered or not, it may retry the
allocation afterwards.  In times past, this would always wake kswapd as
well but currently, kswapd is not woken up after direct reclaim fails.
For order-0 allocations, this makes little difference but if there is a
heavy mix of higher-order allocations that direct reclaim is failing for,
it might mean that kswapd is not rewoken for higher orders as much as it
did previously.

This patch wakes up kswapd when an allocation is being retried after a
direct reclaim failure.  It would be expected that kswapd is already
awake, but this has the effect of telling kswapd to reclaim at the higher
order as well.
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

openipmi list is moderated.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NCorey Minyard <minyard@acm.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the `s' it just won't work.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Acked-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Names with periods or commas need to be quoted
Use tab not spaces
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Integrate P:/M: lines to single M:
Use tabs not spaces
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Jayamohan Kallickal <jayamohank@serverengines.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Integrate P:/M: to single M:
Use tab for spacing
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Jing Huang <huangj@brocade.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Oops.  How did that get there?
(Don't look, it's my original pattern commit...)
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes:
ERROR: "log_start_commit" [fs/ext3/ext3.ko] undefined!
Signed-off-by: NStefan Schmidt <stefan@datenfreihafen.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: fix panic when trying to destroy a newly allocated
  Btrfs: allow more metadata chunk preallocation
  Btrfs: fallback on uncompressed io if compressed io fails
  Btrfs: find ideal block group for caching
  Btrfs: avoid null deref in unpin_extent_cache()
  Btrfs: skip btrfs_release_path in btrfs_update_root and btrfs_del_root
  Btrfs: fix some metadata enospc issues
  Btrfs: fix how we set max_size for free space clusters
  Btrfs: cleanup transaction starting and fix journal_info usage
  Btrfs: fix data allocation hint start

Rafael debugged a resume-time hang (with oopses in workqueue handling)
on his laptop that was due to the 'waker' workqueue entry being
disconnected and then released without the workqueue entry having been
synchronized.

Several people were involved, with Oleg Nesterov doing a debugging patch
showing what workqueue entry was corrupt etc.

This was a regression introduced by commit 7bee549e ("Bluetooth: Add
USB autosuspend support to btusb driver") as Rafael points out (not
actually bisected, but it became clear once the bug was found).
Tested-and-reported-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NOliver Neukum <oliver@neukum.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a problem where iget5_locked will look for an inode, not find it, and
then subsequently try to allocate it.  Another CPU will have raced in and
allocated the inode instead, so when iget5_locked gets the inode spin lock again
and does a search, it finds the new inode.  So it goes ahead and calls
destroy_inode on the inode it just allocated.  The problem is we don't set
BTRFS_I(inode)->root until the new inode is completely initialized.  This patch
makes us set root to NULL when alloc'ing a new inode, so when we get to
btrfs_destroy_inode and we see that root is NULL we can just free up the memory
and continue on.  This fixes the panic

http://www.kerneloops.org/submitresult.php?number=812690

Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6:
  JBD/JBD2: free j_wbuf if journal init fails.
  ext3: Wait for proper transaction commit on fsync
  ext3: retry failed direct IO allocations

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: hda - possible read past array alc88[02]_parse_auto_config()
  sound: rawmidi: fix MIDI device O_APPEND error handling
  sound: rawmidi: fix checking of O_APPEND when opening MIDI device
  sound: rawmidi: fix double init when opening MIDI device with O_APPEND
  ALSA: hda - Avoid quirk for HP dc5750
  ALSA: hda - Tweak OLPC XO-1.5 microphone bias
  ALSA: hda: Use model=auto quirk for Sony VAIO VGN-FW170J using ALC262

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  x86/PCI: Adjust GFP mask handling for coherent allocations
  PCI ASPM: fix oops on root port removal

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc: pasemi_defconfig update
  powerpc: 2.6.32 update of defconfigs for embedded 6xx/7xxx, 8xx, 8{3,5,6}xxx
  powerpc/8xxx: enable IPsec ESP by default on mpc83xx/mpc85xx
  powerpc/83xx: Fix u-boot partion size for MPC8377E-WLAN boards
  powerpc/85xx: Fix USB GPIOs for MPC8569E-MDS boards
  powerpc/82xx: kmalloc failure ignored in ep8248e_mdio_probe()
  powerpc/85xx: sbc8548 - fixup of PCI-e related DTS fields

* master.kernel.org:/home/rmk/linux-2.6-arm:
  ARM: Use a definition for the userspace cmpxchg emulation syscall
  [ARM] Fix test for unimplemented ARM syscalls
  ARM: 5784/1: fix early boot machine ID mismatch error display
  [ARM] orion5x: update defconfig
  [ARM] Kirkwood: update defconfig
  [ARM] Kirkwood: clarify PCIe MEM bus/physical address distinction
  [ARM] kirkwood: fix PCI I/O port assignment
  [ARM] kirkwood: fix section mismatch
  [ARM] OpenRD base: Initialize PCI express and i2c
  [ARM] properly report mv78100 stepping A1
  ARM: 5780/1: KS8695: Fix macro definition bug in regs-switch.c
  ARM: 5779/1: ep93xx/micro9.c: fix implicit declaration of function __raw_readl and IOMEM
  RealView: Add sparsemem support for the RealView PBX platform
  RealView: Remove duplicated #define REALVIEW_SYS_FLAGS* statements
  RealView: Add default memory configuration
  Check whether the SCU was already initialised
  ARMv7: Check whether the SMP/nAMP mode was already enabled
  [ARM] pxa: fix resume failure by saving/restoring IPRx registers
  [ARM] pxa/palm: fix incorrect initialization of Palm Tungsten C keyboard
  [ARM] pxa/zaurus: fix NAND flash OOB layout for Borzoi

* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (52 commits)
  drm/kms: Init the CRTC info fields for modes forced from the command line.
  drm/radeon/r600: CS parser updates
  drm/radeon/kms: add debugfs for power management for AtomBIOS devices
  drm/radeon/kms: initial mode validation support
  drm/radeon/kms/atom/dce3: call transmitter init on mode set
  drm/radeon/kms: store detailed connector info
  drm/radeon/kms/atom/dce3: fix up usPixelClock calculation for Transmitter tables
  drm/radeon/kms/r600: fix rs880 support v2
  drm/radeon/kms/r700: fix some typos in chip init
  drm/radeon/kms: remove some misleading debugging output
  drm/radeon/kms: stop putting VRAM at 0 in MC space on r600s.
  drm/radeon/kms: disable D1VGA and D2VGA if enabled
  drm/radeon/kms: Don't RMW CP_RB_CNTL
  drm/radeon/kms: fix coherency issues on AGP cards.
  drm/radeon/kms: fix rc410 suspend/resume.
  drm/radeon/kms: add quirk for hp dc5750
  drm/radeon/kms/atom: fix potential oops in spread spectrum code
  drm/kms: typo fix
  drm/radeon/kms/atom: Make card_info per device
  drm/radeon/kms/atom: Fix DVO support
  ...

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  highmem: Fix debug_kmap_atomic() to also handle KM_IRQ_PTE, KM_NMI, and KM_NMI_PTE
  highmem: Fix race in debug_kmap_atomic() which could cause warn_count to underflow
  rcu: Fix long-grace-period race between forcing and initialization
  uids: Prevent tear down race

Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: try_one_irq() must be called with irq disabled

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf tools: Fix permission checks
  perf_events: Fix some typo in the perf events config description

Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Use root_task_group_empty only with FAIR_GROUP_SCHED
  sched: Fix kernel-doc function parameter name

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, amd-ucode: Check UCODE_MAGIC before loading the container file
  x86: Fix error return sequence in __ioremap_caller()
  x86: Add Phoenix/MSC BIOSes to lowmem corruption list

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: partial revert to fix double brelse WARNING()
  ext4: Fix return value of ext4_split_unwritten_extents() to fix direct I/O
  ext4: code clean up for dio fallocate handling
  ext4: skip conversion of uninit extents after direct IO if there isn't any
  ext4: fix ext4_ext_direct_IO()'s return value after converting uninit extents
  ext4: discard preallocation when restarting a transaction during truncate

* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
  [WATCHDOG] SBC-FITPC2 watchdog driver registration fix

* 'fixes-s3c-2632-rc6' of git://git.fluff.org/bjdooks/linux:
  ARM: S3C64XX: DMA: Free node for non-circular queues
  ARM: S3C64XX: DMA: Callback with correct buffer pointer
  ARM: S3C64XX: DMA: Make src and dst transfer size same
  ARM: S3C64XX: DMA: Unify callback functions for success/failure
  ARM: S3C64XX: DMA: Protect buffer pointers while manipulation
  ARM: S3C64XX: Tidy definition and comments in s3c_dma_has_circular()
  ARM: S3C64XX: Remove duplicate s3c_dma_has_circular() definition for S3C64xx.
  ARM: SMDK6410: Allocate more GPIO space for WM1190-EV1
  ARM: SMDK6410: Configure GPIO pull up for WM835x IRQ line

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (27 commits)
  V4L/DVB (13314): saa7134: set ts_force_val for the Hauppauge WinTV HVR-1150
  V4L/DVB (13313): saa7134: add support for FORCE_TS_VALID mode for mpeg ts input
  V4L/DVB (13311): uvcvideo: Fix compilation warning with 2.6.32 due to type mismatch with abs()
  V4L/DVB (13309): uvcvideo: Ignore the FIX_BANDWIDTH for compressed video
  V4L/DVB (13287): ce6230 - saa7164-cmd: Fix wrong sizeof
  V4L/DVB (13286): pxa-camera: Fix missing sched.h
  V4L/DVB (13264): gspca_mr97310a: Change vstart for CIF sensor type 1 cams
  V4L/DVB (13257): gspca - m5602-s5k4aa: Add vflip for Fujitsu Amilo Xi 2528
  V4L/DVB (13256): gspca - m5602-s5k4aa: Add another MSI GX700 vflip quirk
  V4L/DVB (13255): gspca - m5602-s5k4aa: Add vflip quirk for the Bruneinit laptop
  V4L/DVB (13240): firedtv: fix regression: tuning fails due to bogus error return
  V4L/DVB (13237): firedtv: length field corrupt in ca2host if length>127
  V4L/DVB (13230): s2255drv: Don't conditionalize video buffer completion on waiting processes
  V4L/DVB (13202): smsusb: add autodetection support for three additional Hauppauge USB IDs
  V4L/DVB (13190): em28xx: fix panic that can occur when starting audio streaming
  V4L/DVB (13170): bttv: Fix reversed polarity error when switching video standard
  V4L/DVB (13169): bttv: Fix potential out-of-order field processing
  V4L/DVB (13167): pt1: Fix a compile error on arm
  V4L/DVB (13132): fix use-after-free Oops, resulting from a driver-core API change
  V4L/DVB (13131): pxa_camera: fix camera pixel format configuration
  ...

On an FS where all of the space has not been allocated into chunks yet,
the enospc can return enospc just because the existing metadata chunks
are full.

We get around this by allowing more metadata chunks to be allocated up
to a certain limit, and finding the right limit is a little fuzzy.  The
problem is the reservations for delalloc would preallocate way too much
of the FS as metadata.  We need to start saying no and just force some
IO to happen.

But we also need to let a reasonable amount of the FS become metadata.
This bumps the hard limit up, later releases will have a better system.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Currently compressed IO does not deal with not having its entire extent able to
be allocated.  So if we have enough free space to allocate for the extent, but
its not contiguous, it will fail spectacularly.  This patch fixes this by
falling back on uncompressed IO which lets us spread the delalloc extent across
multiple extents.  I tested this by making us randomly think the reservation had
failed to make it fallback on the uncompressed io way and it seemed to work
fine.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch changes a few things.  Hopefully the comments are helpfull, but
I'll try and be as verbose here.

Problem:

My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space.  The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system.  So

Solution:

1) Don't cache block groups willy-nilly at first.  Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.

2) Don't be so picky about cached block groups.  The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more.  So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.

There is one other tweak in here.  Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation.  This could make us end up with way too many chunks, so keep
track of this particular case.

With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

I re-orderred the checks to avoid dereferencing "em" if it was null.

Found by smatch static checker.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We don't need to call btrfs_release_path because btrfs_free_path will do
that for us.
Signed-off-by: NLi Dongyang <Jerry87905@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We weren't reserving metadata space for rename, rmdir and unlink, which could
cause problems.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This patch fixes a problem where max_size can be set to 0 even though we
filled the cluster properly.  We set max_size to 0 if we restart the cluster
window, but if the new start entry is big enough to be our new cluster then we
could return with a max_size set to 0, which will mean the next time we try to
allocate from this cluster it will fail.  So set max_extent to the entry's
size.  Tested this on my box and now we actually allocate from the cluster
after we fill it.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We use journal_info to tell if we're in a nested transaction to make sure we
don't commit the transaction within a nested transaction.  We use another
method to see if there are any outstanding ioctl trans handles, so if we're
starting one do not set current->journal_info, since it will screw with other
filesystems.  This patch also cleans up the starting stuff so there aren't any
magic numbers.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Sometimes our start allocation hint when we cow a file can be either
EXTENT_HOLE or some other such place holder, which is not optimal.  So if we
find that our em->block_start is one of these special values, check to see
where the first block of the inode is stored, and use that as a hint.  If that
block is also a special value, just fallback on a hint of 0 and let the
allocator figure out a good place to put the data.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>