This patch improves the space balancing code to keep more sharing
of tree blocks. The only case that breaks sharing of tree blocks is
data extents get fragmented during balancing. The main changes in
this patch are:

Add a 'drop sub-tree' function. This solves the problem in old code
that BTRFS_HEADER_FLAG_WRITTEN check breaks sharing of tree block.

Remove relocation mapping tree. Relocation mappings are stored in
struct btrfs_ref_path and updated dynamically during walking up/down
the reference path. This reduces CPU usage and simplifies code.

This patch also fixes a bug. Root items for reloc trees should be
updated in btrfs_free_reloc_root.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

This is a large change for adding compression on reading and writing,
both for inline and regular extents.  It does some fairly large
surgery to the writeback paths.

Compression is off by default and enabled by mount -o compress.  Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.

If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.

* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler.  This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.

* Inline extents are inserted at delalloc time now.  This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.

* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.

From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field.  Neither the encryption or the
'other' field are currently used.

In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k.  This is a
software only limit, the disk format supports u64 sized compressed extents.

In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k.  This is a software only limit
and will be subject to tuning later.

Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data.  This way additional encodings can be
layered on without having to figure out which encoding to checksum.

Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread.  This makes it tricky to
spread the compression load across all the cpus on the box.  We'll have to
look at parallel pdflush walks of dirty inodes at a later time.

Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Merge branch 'master' of ssh://mason@master.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

Sometimes we end up freeing a reserved extent because we don't need it, however
this means that its possible for transaction->last_alloc to point to the middle
of a free area.

When we search for free space in find_free_space we do a tree_search_offset
with contains set to 0, because we want it to find the next best free area if
we do not have an offset starting on the given offset.

Unfortunately that currently means that if the offset we were given as a hint
points to the middle of a free area, we won't find anything.  This is especially
bad if we happened to last allocate from the big huge chunk of a newly formed
block group, since we won't find anything and have to go back and search the
long way around.

This fixes this problem by making it so that we return the free space area
regardless of the contains variable.  This made cache missing happen _alot_
less, and speeds things up considerably.
Signed-off-by: Josef Bacik <jbacik@redhat.com>

Subvol creation already requires privs, and security_inode_mkdir isn't
exported.  For now we don't need it.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

This is debatable, but while we're debating it, let's disallow the
combination of splice and an O_APPEND destination.

It's not entirely clear what the semantics of O_APPEND should be, and
POSIX apparently expects pwrite() to ignore O_APPEND, for example.  So
we could make up any semantics we want, including the old ones.

But Miklos convinced me that we should at least give it some thought,
and that accepting writes at arbitrary offsets is wrong at least for
IS_APPEND() files (which always have O_APPEND set, even if the reverse
isn't true: you can obviously have O_APPEND set on a regular file).

So disallow O_APPEND entirely for now.  I doubt anybody cares, and this
way we have one less gray area to worry about.
Reported-and-argued-for-by: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Jens Axboe <ens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'hwmon-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6:
  hwmon: (abituguru3) Enable DMI probing feature on Abit AT8 32X
  hwmon: (abituguru3) Enable reading from AUX3 fan on Abit AT8 32X
  hwmon: (adt7473) Fix some bogosity in documentation file
  hwmon: Define sysfs interface for energy consumption register
  hwmon: (it87) Prevent power-off on Shuttle SN68PT
  eeepc-laptop: Fix hwmon interface

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] correct broken links and email addresses

This fixes the previous fix, which was completely wrong on closer
inspection. This version has been manually tested with a user-space
test harness and generates sane values. A nearly identical patch has
been boot-tested.

The problem arose from changing how kmalloc/kfree handled alignment
padding without updating ksize to match. This brings it in sync.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Replace the no longer working links and email address in the
documentation and in source code.
Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Dave Jones <davej@redhat.com>

Creating a subvolume is in many ways like a normal VFS ->mkdir, and we
really need to play with the VFS topology locking rules.  So instead of
just creating the snapshot on disk and then later getting rid of
confliting aliases do it correctly from the start.  This will become
especially important once we allow for subvolumes anywhere in the tree,
and not just below a hidden root.

Note that snapshots will need the same treatment, but do to the delay
in creating them we can't do it currently.  Chris promised to fix that
issue, so I'll wait on that.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Signed-off-by: Chris Mason <chris.mason@oracle.com>

This fixes the btrfs makefile for building in the tree and out of the tree
both as a module and static.
Signed-off-by: Chris Mason <chris.mason@oracle.com>

Due to the optimization for truncate, tree leaves only containing
checksum items can be deleted without being COW'ed first. This causes
reference cache misses. The way to fix the miss is create cache
entries for tree leaves only contain checksum.

This patch also fixes a -EEXIST issue in shared reference cache.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

The offset field in struct btrfs_extent_ref records the position
inside file that file extent is referenced by. In the new back
reference system, tree leaves holding references to file extent
are recorded explicitly. We can scan these tree leaves very quickly, so the
offset field is not required.

This patch also makes the back reference system check the objectid
when extents are in deleting.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

This patch makes btrfs count space allocated to file in bytes instead
of 512 byte sectors.

Everything else in btrfs uses a byte count instead of sector sizes or
blocks sizes, so this fits better.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

Enable driver checking of the DMI product name (when enabled) on
an Abit AT8 32X, instead of falling back to a manual probe. This
eliminates false negatives and eventually will help avoid
unnecessary bus probes on unsupported mainboards.
Signed-off-by: Alistair John Strachan <alistair@devzero.co.uk>
Tested-by: Daniel Exner <dex@dragonslave.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

The table for the Abit AT8 32X was incorrectly missing an entry
for the sixth ("AUX3") fan. Add this entry, exporting the fan
reading to userspace.

Closes lm-sensors.org ticket #2339.
Signed-off-by: Alistair John Strachan <alistair@devzero.co.uk>
Tested-by: Daniel Exner <dex@dragonslave.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Describe the sysfs files that were introduced in the ibmaem driver.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

On the Shuttle SN68PT, FAN_CTL2 is apparently not connected to a fan,
but to something else. One user has reported instant system power-off
when changing the PWM2 duty cycle, so we disable it.

I use the board name string as the trigger in case the same board is
ever used in other systems.

This closes lm-sensors ticket #2349:
pwmconfig causes a hard poweroff
http://www.lm-sensors.org/ticket/2349Signed-off-by: Jean Delvare <khali@linux-fr.org>

Creates a name file in the sysfs directory, that
is needed for the libsensors library to work.
Also rename fan1_pwm to pwm1 and scale its value as needed.

This fixes bug #11520:
http://bugzilla.kernel.org/show_bug.cgi?id=11520Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  [MIPS] Sibyte: Register PIO PATA device only for Swarm and Litte Sur

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  tcp: Fix tcp_hybla zero congestion window growth with small rho and large cwnd.
  net: Fix netdev_run_todo dead-lock
  tcp: Fix possible double-ack w/ user dma
  net: only invoke dev->change_rx_flags when device is UP
  netrom: Fix sock_orphan() use in nr_release
  ax25: Quick fix for making sure unaccepted sockets get destroyed.
  Revert "ax25: Fix std timer socket destroy handling."
  [Bluetooth] Add reset quirk for A-Link BlueUSB21 dongle
  [Bluetooth] Add reset quirk for new Targus and Belkin dongles
  [Bluetooth] Fix double frees on error paths of btusb and bpa10x drivers

Symbol name spaghetti which is too complicated to cleanup on this stage
of the release cycle breaks the build on BCM1480 platforms.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Because of rounding, in certain conditions, i.e. when in congestion
avoidance state rho is smaller than 1/128 of the current cwnd, TCP
Hybla congestion control starves and the cwnd is kept constant
forever.

This patch forces an increment by one segment after #send_cwnd calls
without increments(newreno behavior).
Signed-off-by: Daniele Lacamera <root@danielinux.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Benjamin Thery tracked down a bug that explains many instances
of the error

unregister_netdevice: waiting for %s to become free. Usage count = %d

It turns out that netdev_run_todo can dead-lock with itself if
a second instance of it is run in a thread that will then free
a reference to the device waited on by the first instance.

The problem is really quite silly.  We were trying to create
parallelism where none was required.  As netdev_run_todo always
follows a RTNL section, and that todo tasks can only be added
with the RTNL held, by definition you should only need to wait
for the very ones that you've added and be done with it.

There is no need for a second mutex or spinlock.

This is exactly what the following patch does.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

From: Ali Saidi <saidi@engin.umich.edu>

When TCP receive copy offload is enabled it's possible that
tcp_rcv_established() will cause two acks to be sent for a single
packet. In the case that a tcp_dma_early_copy() is successful,
copied_early is set to true which causes tcp_cleanup_rbuf() to be
called early which can send an ack. Further along in
tcp_rcv_established(), __tcp_ack_snd_check() is called and will
schedule a delayed ACK. If no packets are processed before the delayed
ack timer expires the packet will be acked twice.
Signed-off-by: David S. Miller <davem@davemloft.net>

Jesper Dangaard Brouer <hawk@comx.dk> reported a bug when setting a VLAN
device down that is in promiscous mode:

When the VLAN device is set down, the promiscous count on the real
device is decremented by one by vlan_dev_stop(). When removing the
promiscous flag from the VLAN device afterwards, the promiscous
count on the real device is decremented a second time by the
vlan_change_rx_flags() callback.

The root cause for this is that the ->change_rx_flags() callback is
invoked while the device is down. The synchronization is meant to mirror
the behaviour of the ->set_rx_mode callbacks, meaning the ->open function
is responsible for doing a full sync on open, the ->close() function is
responsible for doing full cleanup on ->stop() and ->change_rx_flags()
is meant to do incremental changes while the device is UP.

Only invoke ->change_rx_flags() while the device is UP to provide the
intended behaviour.
Tested-by: Jesper Dangaard Brouer <jdb@comx.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

SLOB's ksize calculation was braindamaged and generally harmlessly
underreported the allocation size. But for very small buffers, it could
in fact overreport them, leading code depending on krealloc to overrun
the allocation and trample other data.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Tested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This reverts commit 135aedc3, as
requested by Hans Verkuil.

It was a patch for 2.6.28 where the BKL was pushed down from v4l core to
the drivers, not for 2.6.27!
Requested-by: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-of-by: Linus Torvalds <torvalds@linux-foundation.org>

* Theodore Ts'o (tytso@mit.edu) wrote:
>
> I've been playing with adding some markers into ext4 to see if they
> could be useful in solving some problems along with Systemtap.  It
> appears, though, that as of 2.6.27-rc8, markers defined in code which is
> compiled directly into the kernel (i.e., not as modules) don't show up
> in Module.markers:
>
> kvm_trace_entryexit arch/x86/kvm/kvm-intel  %u %p %u %u %u %u %u %u
> kvm_trace_handler arch/x86/kvm/kvm-intel  %u %p %u %u %u %u %u %u
> kvm_trace_entryexit arch/x86/kvm/kvm-amd  %u %p %u %u %u %u %u %u
> kvm_trace_handler arch/x86/kvm/kvm-amd  %u %p %u %u %u %u %u %u
>
> (Note the lack of any of the kernel_sched_* markers, and the markers I
> added for ext4_* and jbd2_* are missing as wel.)
>
> Systemtap apparently depends on in-kernel trace_mark being recorded in
> Module.markers, and apparently it's been claimed that it used to be
> there.  Is this a bug in systemtap, or in how Module.markers is getting
> built?   And is there a file that contains the equivalent information
> for markers located in non-modules code?

I think the problem comes from "markers: fix duplicate modpost entry"
(commit d35cb360)

Especially :

  -   add_marker(mod, marker, fmt);
  +   if (!mod->skip)
  +     add_marker(mod, marker, fmt);
    }
    return;
   fail:

Here is a fix that should take care if this problem.

Thanks for the bug report!
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Tested-by: "Theodore Ts'o" <tytso@mit.edu>
CC: Greg KH <greg@kroah.com>
CC: David Smith <dsmith@redhat.com>
CC: Roland McGrath <roland@redhat.com>
CC: Sam Ravnborg <sam@ravnborg.org>
CC: Wenji Huang <wenji.huang@oracle.com>
CC: Takashi Nishiie <t-nishiie@np.css.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kgdb: call touch_softlockup_watchdog on resume
  kgdb, x86: Avoid invoking kgdb_nmicallback twice per NMI

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: gart iommu have direct mapping when agp is present too

* git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6:
  ide: workaround for bogus gcc warning in ide_sysfs_register_port()
  ide-cd: Optiarc DVD RW AD-7200A does play audio
  IDE: Fix platform device registration in Swarm IDE driver (v2)
  ide-dma: fix ide_build_dmatable() for TRM290
  ide-cd: temporary tray close fix

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  [MIPS] IP27: Fix build errors if CONFIG_MAPPED_KERNEL=y
  [MIPS] Fix CMP Kconfig configuration and mark as broken.

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/v4l-dvb: (33 commits)
  V4L/DVB (9103): em28xx: HVR-900 B3C0 - fix audio clicking issue
  V4L/DVB (9099): em28xx: Add detection for K-WORLD DVB-T 310U
  V4L/DVB (9092): gspca: Bad init values for sonixj ov7660.
  V4L/DVB (9080): gspca: Add a delay after writing to the sonixj sensors.
  V4L/DVB (9075): gspca: Bad check of returned status in i2c_read() spca561.
  V4L/DVB (9053): fix buffer overflow in uvc-video
  V4L/DVB (9043): S5H1420: Fix size of shadow-array to avoid overflow
  V4L/DVB (9037): Fix support for Hauppauge Nova-S SE
  V4L/DVB (9029): Fix deadlock in demux code
  V4L/DVB (8979): sms1xxx: Add new USB product ID for Hauppauge WinTV MiniStick
  V4L/DVB (8978): sms1xxx: fix product name for Hauppauge WinTV MiniStick
  V4L/DVB (8967): Use correct XC3028L firmware for AMD ATI TV Wonder 600
  V4L/DVB (8963): s2255drv field count fix
  V4L/DVB (8961): zr36067: Fix RGBR pixel format
  V4L/DVB (8960): drivers/media/video/cafe_ccic.c needs mm.h
  V4L/DVB (8958): zr36067: Return proper bytes-per-line value
  V4L/DVB (8957): zr36067: Restore the default pixel format
  V4L/DVB (8955): bttv: Prevent NULL pointer dereference in radio_open
  V4L/DVB (8935): em28xx-cards: Remove duplicate entry (EM2800_BOARD_KWORLD_USB2800)
  V4L/DVB (8933): gspca: Disable light frquency for zc3xx cs2102 Kokom.
  ...