Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
this driver might return -EPROBE_DEFER if a gpio_request fails.

Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
and 04bf3011 ("regulator: Support driver probe deferral") this driver
might return -EPROBE_DEFER if a gpio_request or regulator_get fails.

Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
this driver might return -EPROBE_DEFER if a gpio_request fails.

Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
this driver might return -EPROBE_DEFER if a gpio_request fails.

Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
this driver might return -EPROBE_DEFER if a gpio_request fails.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
this driver might return -EPROBE_DEFER if the mmc_gpio_request_cd fails.

Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Chris Ball <cjb@laptop.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Prevent drivers relying on platform_driver_probe from requesting
deferred probing in order to avoid further futile probe attempts (either
the driver has been unregistered or its probe function has been set to
platform_drv_probe_fail when probing is retried).

Note that several platform drivers currently return subsystem errors
from probe and that these can include -EPROBE_DEFER (e.g. if a gpio
request fails).

Add a warning to platform_drv_probe that can be used to catch drivers
that inadvertently request probe deferral while using
platform_driver_probe.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A common way to handle kobject lifetimes in embedded in objects with
different lifetime rules is to pair the kobject with a struct completion.

This introduces a kobj_completion structure that can be used in place
of the pairing, along with several convenience functions for
initialization, release, and put-and-wait.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

I had a typo in a variable name for the previous patch (SCSI: fcoe:
convert bus code to use bus_group) that broke the build, this fixes
that.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The drv_attrs field of struct bus_type is going away soon, drv_groups
should be used instead.  This converts the PCI bus code to use the
correct field.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The bus_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the PCI bus code to use the
correct field.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The dev_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the pmu bus code to use
the correct field.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The bus_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the fcoe bus code to use the
correct field.

Cc: Robert Love <robert.w.love@intel.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The bus_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the VIO bus code to use the
correct field.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The bus_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the ibmebus bus code to use the
correct field.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The bus_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the rapidio bus code to use the
correct field.

Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The direct firmware loading interface is a bit quiet about failures.  Failures
that occur during loading are masked if firmware exists in multiple locations,
and may be masked entirely in the event that we fall back to the user mode
helper code.  It would be nice to see some of the more unexpected errors get
logged, so in the event that you expect the direct firmware loader to work (like
if CONFIG_FW_LOADER_USER_HELPER is enabled), and something goes wrong, you can
figure out what happened.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Some internal sysfs functions which take explicit namespace argument
are weird in that they place the optional @ns in front of @name which
is contrary to the established convention.  This is confusing and
error-prone especially as @ns and @name may be interchanged without
causing compilation warning.

Swap the positions of @name and @ns in the following internal
functions.

 sysfs_find_dirent()
 sysfs_rename()
 sysfs_hash_and_remove()
 sysfs_name_hash()
 sysfs_name_compare()
 create_dir()

This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The pre-existing sysfs interfaces which take explicit namespace
argument are weird in that they place the optional @ns in front of
@name which is contrary to the established convention.  For example,
we end up forcing vast majority of sysfs_get_dirent() users to do
sysfs_get_dirent(parent, NULL, name), which is silly and error-prone
especially as @ns and @name may be interchanged without causing
compilation warning.

This renames sysfs_get_dirent() to sysfs_get_dirent_ns() and swap the
positions of @name and @ns, and sysfs_get_dirent() is now a wrapper
around sysfs_get_dirent_ns().  This makes confusions a lot less
likely.

There are other interfaces which take @ns before @name.  They'll be
updated by following patches.

This patch doesn't introduce any functional changes.

v2: EXPORT_SYMBOL_GPL() wasn't updated leading to undefined symbol
    error on module builds.  Reported by build test robot.  Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The way namespace tags are implemented in sysfs is more complicated
than necessary.  As each tag is a pointer value and required to be
non-NULL under a namespace enabled parent, there's no need to record
separately what type each tag is or where namespace is enabled.

If multiple namespace types are needed, which currently aren't, we can
simply compare the tag to a set of allowed tags in the superblock
assuming that the tags, being pointers, won't have the same value
across multiple types.  Also, whether to filter by namespace tag or
not can be trivially determined by whether the node has any tagged
children or not.

This patch rips out kobj_ns_type handling from sysfs.  sysfs no longer
cares whether specific type of namespace is enabled or not.  If a
sysfs_dirent has a non-NULL tag, the parent is marked as needing
namespace filtering and the value is tested against the allowed set of
tags for the superblock (currently only one but increasing this number
isn't difficult) and the sysfs_dirent is ignored if it doesn't match.

This removes most kobject namespace knowledge from sysfs proper which
will enable proper separation and layering of sysfs.  The namespace
sanity checks in fs/sysfs/dir.c are replaced by the new sanity check
in kobject_namespace().  As this is the only place ktype->namespace()
is called for sysfs, this doesn't weaken the sanity check
significantly.  I omitted converting the sanity check in
sysfs_do_create_link_sd().  While the check can be shifted to upper
layer, mistakes there are well contained and should be easily visible
anyway.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There's no reason for sysfs to be calling ktype->namespace().  It is
backwards, obfuscates what's going on and unnecessarily tangles two
separate layers.

There are two places where symlink code calls ktype->namespace().

* sysfs_do_create_link_sd() calls it to find out the namespace tag of
  the target directory.  Unless symlinking races with cross-namespace
  renaming, this equals @target_sd->s_ns.

* sysfs_rename_link() uses it to find out the new namespace to rename
  to and the new namespace can be different from the existing one.
  The function is renamed to sysfs_rename_link_ns() with an explicit
  @ns argument and the ktype->namespace() invocation is shifted to the
  device layer.

While this patch replaces ktype->namespace() invocation with the
recorded result in @target_sd, this shouldn't result in any behvior
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For some unrecognizable reason, namespace information is communicated
to sysfs through ktype->namespace() callback when there's *nothing*
which needs the use of a callback.  The whole sequence of operations
is completely synchronous and sysfs operations simply end up calling
back into the layer which just invoked it in order to find out the
namespace information, which is completely backwards, obfuscates
what's going on and unnecessarily tangles two separate layers.

This patch doesn't remove ktype->namespace() but shifts its handling
to kobject layer.  We probably want to get rid of the callback in the
long term.

This patch adds an explicit param to sysfs_{create|rename|move}_dir()
and renames them to sysfs_{create|rename|move}_dir_ns(), respectively.
ktype->namespace() invocations are moved to the calling sites of the
above functions.  A new helper kboject_namespace() is introduced which
directly tests kobj_ns_type_operations->type which should give the
same result as testing sysfs_fs_type(parent_sd) and returns @kobj's
namespace tag as necessary.  kobject_namespace() is extern as it will
be used from another file in the following patches.

This patch should be an equivalent conversion without any functional
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sysfs ns (namespace) implementation became more convoluted than
necessary while trying to hide ns information from visible interface.
The relatively recent attr ns support is a good example.

* attr ns tag is determined by sysfs_ops->namespace() callback while
  dir tag is determined by kobj_type->namespace().  The placement is
  arbitrary.

* Instead of performing operations with explicit ns tag, the namespace
  callback is routed through sysfs_attr_ns(), sysfs_ops->namespace(),
  class_attr_namespace(), class_attr->namespace().  It's not simpler
  in any sense.  The only thing this convolution does is traversing
  the whole stack backwards.

The namespace callbacks are unncessary because the operations involved
are inherently synchronous.  The information can be provided in in
straight-forward top-down direction and reversing that direction is
unnecessary and against basic design principles.

This backward interface is unnecessarily convoluted and hinders
properly separating out sysfs from driver model / kobject for proper
layering.  This patch updates attr ns support such that

* sysfs_ops->namespace() and class_attr->namespace() are dropped.

* sysfs_{create|remove}_file_ns(), which take explicit @ns param, are
  added and sysfs_{create|remove}_file() are now simple wrappers
  around the ns aware functions.

* ns handling is dropped from sysfs_chmod_file().  Nobody uses it at
  this point.  sysfs_chmod_file_ns() can be added later if necessary.

* Explicit @ns is propagated through class_{create|remove}_file_ns()
  and netdev_class_{create|remove}_file_ns().

* driver/net/bonding which is currently the only user of attr
  namespace is updated to use netdev_class_{create|remove}_file_ns()
  with @bh->net as the ns tag instead of using the namespace callback.

This patch should be an equivalent conversion without any functional
difference.  It makes the code easier to follow, reduces lines of code
a bit and helps proper separation and layering.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The expansion of to_sysfs_dirent() contains an unncessary trailing
semicolon making it impossible to use in the middle of statements.
Drop it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull staging fixes from Greg KH:
 "Here are a number of small staging tree and iio driver fixes.  Nothing
  major, just lots of little things"

* tag 'staging-3.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (34 commits)
  iio:buffer_cb: Add missing iio_buffer_init()
  iio: Prevent race between IIO chardev opening and IIO device free
  iio: fix: Keep a reference to the IIO device for open file descriptors
  iio: Stop sampling when the device is removed
  iio: Fix crash when scan_bytes is computed with active_scan_mask == NULL
  iio: Fix mcp4725 dev-to-indio_dev conversion in suspend/resume
  iio: Fix bma180 dev-to-indio_dev conversion in suspend/resume
  iio: Fix tmp006 dev-to-indio_dev conversion in suspend/resume
  iio: iio_device_add_event_sysfs() bugfix
  staging: iio: ade7854-spi: Fix return value
  staging:iio:hmc5843: Fix measurement conversion
  iio: isl29018: Fix uninitialized value
  staging:iio:dummy fix kfifo_buf kconfig dependency issue if kfifo modular and buffer enabled for built in dummy driver.
  iio: at91: fix adc_clk overflow
  staging: line6: add bounds check in snd_toneport_source_put()
  Staging: comedi: Fix dependencies for drivers misclassified as PCI
  staging: r8188eu: Adjust RX gain
  staging: r8188eu: Fix smatch warning in core/rtw_ieee80211.
  staging: r8188eu: Fix smatch error in core/rtw_mlme_ext.c
  staging: r8188eu: Fix Smatch off-by-one warning in hal/rtl8188e_hal_init.c
  ...

Pull USB fixes from Greg KH:
 "Here are a number of small USB fixes for 3.12-rc2.

  One is a revert of a EHCI change that isn't quite ready for 3.12.
  Others are minor things, gadget fixes, Kconfig fixes, and some quirks
  and documentation updates.

  All have been in linux-next for a bit"

* tag 'usb-3.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: pl2303: distinguish between original and cloned HX chips
  USB: Faraday fotg210: fix email addresses
  USB: fix typo in usb serial simple driver Kconfig
  Revert "USB: EHCI: support running URB giveback in tasklet context"
  usb: s3c-hsotg: do not disconnect gadget when receiving ErlySusp intr
  usb: s3c-hsotg: fix unregistration function
  usb: gadget: f_mass_storage: reset endpoint driver data when disabled
  usb: host: fsl-mph-dr-of: Staticize local symbols
  usb: gadget: f_eem: Staticize eem_alloc
  usb: gadget: f_ecm: Staticize ecm_alloc
  usb: phy: omap-usb3: Fix return value
  usb: dwc3: gadget: avoid memory leak when failing to allocate all eps
  usb: dwc3: remove extcon dependency
  usb: gadget: add '__ref' for rndis_config_register() and cdc_config_register()
  usb: dwc3: pci: add support for BayTrail
  usb: gadget: cdc2: fix conversion to new interface of f_ecm
  usb: gadget: fix a bug and a WARN_ON in dummy-hcd
  usb: gadget: mv_u3d_core: fix violation of locking discipline in mv_u3d_ep_disable()

Pull drm fixes from Dave Airlie:
 - some small fixes for msm and exynos
 - a regression revert affecting nouveau users with old userspace
 - intel pageflip deadlock and gpu hang fixes, hsw modesetting hangs

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (22 commits)
  Revert "drm: mark context support as a legacy subsystem"
  drm/i915: Don't enable the cursor on a disable pipe
  drm/i915: do not update cursor in crtc mode set
  drm/exynos: fix return value check in lowlevel_buffer_allocate()
  drm/exynos: Fix address space warnings in exynos_drm_fbdev.c
  drm/exynos: Fix address space warning in exynos_drm_buf.c
  drm/exynos: Remove redundant OF dependency
  drm/msm: drop unnecessary set_need_resched()
  drm/i915: kill set_need_resched
  drm/msm: fix potential NULL pointer dereference
  drm/i915/dvo: set crtc timings again for panel fixed modes
  drm/i915/sdvo: Robustify the dtd<->drm_mode conversions
  drm/msm: workaround for missing irq
  drm/msm: return -EBUSY if bo still active
  drm/msm: fix return value check in ERR_PTR()
  drm/msm: fix cmdstream size check
  drm/msm: hangcheck harder
  drm/msm: handle read vs write fences
  drm/i915/sdvo: Fully translate sync flags in the dtd->mode conversion
  drm/i915: Use proper print format for debug prints
  ...

Pull block IO fixes from Jens Axboe:
 "After merge window, no new stuff this time only a collection of neatly
  confined and simple fixes"

* 'for-3.12/core' of git://git.kernel.dk/linux-block:
  cfq: explicitly use 64bit divide operation for 64bit arguments
  block: Add nr_bios to block_rq_remap tracepoint
  If the queue is dying then we only call the rq->end_io callout. This leaves bios setup on the request, because the caller assumes when the blk_execute_rq_nowait/blk_execute_rq call has completed that the rq->bios have been cleaned up.
  bio-integrity: Fix use of bs->bio_integrity_pool after free
  blkcg: relocate root_blkg setting and clearing
  block: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...)
  block: trace all devices plug operation

Pull btrfs fixes from Chris Mason:
 "These are mostly bug fixes and a two small performance fixes.  The
  most important of the bunch are Josef's fix for a snapshotting
  regression and Mark's update to fix compile problems on arm"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (25 commits)
  Btrfs: create the uuid tree on remount rw
  btrfs: change extent-same to copy entire argument struct
  Btrfs: dir_inode_operations should use btrfs_update_time also
  btrfs: Add btrfs: prefix to kernel log output
  btrfs: refuse to remount read-write after abort
  Btrfs: btrfs_ioctl_default_subvol: Revert back to toplevel subvolume when arg is 0
  Btrfs: don't leak transaction in btrfs_sync_file()
  Btrfs: add the missing mutex unlock in write_all_supers()
  Btrfs: iput inode on allocation failure
  Btrfs: remove space_info->reservation_progress
  Btrfs: kill delay_iput arg to the wait_ordered functions
  Btrfs: fix worst case calculator for space usage
  Revert "Btrfs: rework the overcommit logic to be based on the total size"
  Btrfs: improve replacing nocow extents
  Btrfs: drop dir i_size when adding new names on replay
  Btrfs: replay dir_index items before other items
  Btrfs: check roots last log commit when checking if an inode has been logged
  Btrfs: actually log directory we are fsync()'ing
  Btrfs: actually limit the size of delalloc range
  Btrfs: allocate the free space by the existed max extent size when ENOSPC
  ...

'samples' is 64bit operant, but do_div() second parameter is 32.
do_div silently truncates high 32 bits and calculated result
is invalid.

In case if low 32bit of 'samples' are zeros then do_div() produces
kernel crash.
Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge tag 'iio-fixes-for-3.12a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

First round of IIO fixes for 3.12

A series of wrong 'struct dev' assumptions in suspend/resume callbacks
following on from this issue being identified in a new driver review.
One to watch out for in future.

A number of driver specific fixes
1) at91 - fix a overflow in clock rate computation
2) dummy - Kconfig dependency issue
3) isl29018 - uninitialized value
4) hmc5843 - measurement conversion bug introduced by recent cleanup.
5) ade7854-spi - wrong return value.

Some IIO core fixes
1) Wrong value picked up for event code creation for a modified channel
2) A null dereference on failure to initialize a buffer after no buffer has
   been in use, when using the available_scan_masks approach.
3) Sampling not stopped when a device is removed. Effects forced removal
   such as hot unplugging.
4) Prevent device going away if a chrdev is still open in userspace.
5) Prevent race on chardev opening and device being freed.
6) Add a missing iio_buffer_init in the call back buffer.

These last few are the first part of a set from Lars-Peter Clausen who
has been taking a closer look at our removal paths and buffer handling
than anyone has for quite some time.

Pull NFS client bugfix from Trond Myklebust:
 "Fix a regression due to incorrect sharing of gss auth caches"

* tag 'nfs-for-3.12-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  RPCSEC_GSS: fix crash on destroying gss auth

Adding the number of bios in a remapped request to 'block_rq_remap'
tracepoint.

Request remapper clones bios in a request to track the completion
status of each bio. So the number of bios can be useful information
for investigation.

Related discussions:
  http://www.redhat.com/archives/dm-devel/2013-August/msg00084.html
  http://www.redhat.com/archives/dm-devel/2013-September/msg00024.htmlSigned-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Users have been complaining of the uuid tree stuff warning that there is no uuid
root when trying to do snapshot operations.  This is because if you mount -o ro
we will not create the uuid tree.  But then if you mount -o rw,remount we will
still not create it and then any subsequent snapshot/subvol operations you try
to do will fail gloriously.  Fix this by creating the uuid_root on remount rw if
it was not already there.  Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

btrfs_ioctl_file_extent_same() uses __put_user_unaligned() to copy some data
back to it's argument struct. Unfortunately, not all architectures provide
__put_user_unaligned(), so compiles break on them if btrfs is selected.

Instead, just copy the whole struct in / out at the start and end of
operations, respectively.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Commit 2bc55652 (Btrfs: don't update atime on
RO subvolumes) ensures that the access time of an inode is not updated when
the inode lives in a read-only subvolume.
However, if a directory on a read-only subvolume is accessed, the atime is
updated. This results in a write operation to a read-only subvolume. I
believe that access times should never be updated on read-only subvolumes.

To reproduce:

 # mkfs.btrfs -f /dev/dm-3
 (...)
 # mount /dev/dm-3 /mnt
 # btrfs subvol create /mnt/sub
 	Create subvolume '/mnt/sub'
 # mkdir /mnt/sub/dir
 # echo "abc" > /mnt/sub/dir/file
 # btrfs subvol snapshot -r /mnt/sub /mnt/rosnap
 	Create a readonly snapshot of '/mnt/sub' in '/mnt/rosnap'
 # stat /mnt/rosnap/dir
 	File: `/mnt/rosnap/dir'
 	Size: 8         Blocks: 0          IO Block: 4096   directory
 Device: 16h/22d    Inode: 257         Links: 1
 Access: (0755/drwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
 	Access: 2013-09-11 07:21:49.389157126 -0400
 	Modify: 2013-09-11 07:22:02.330156079 -0400
 	Change: 2013-09-11 07:22:02.330156079 -0400
 # ls /mnt/rosnap/dir
 	file
 # stat /mnt/rosnap/dir
 	File: `/mnt/rosnap/dir'
 	Size: 8         Blocks: 0          IO Block: 4096   directory
 Device: 16h/22d    Inode: 257         Links: 1
 Access: (0755/drwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
 	Access: 2013-09-11 07:22:56.797151670 -0400
 	Modify: 2013-09-11 07:22:02.330156079 -0400
 	Change: 2013-09-11 07:22:02.330156079 -0400
Reported-by: Koen De Wit <koen.de.wit@oracle.com>
Signed-off-by: Guangyu Sun <guangyu.sun@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

The kernel log entries for device label %s and device fsid %pU
are missing the btrfs: prefix. Add those here.
Signed-off-by: Frank Holton <fholton@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

It's still possible to flip the filesystem into RW mode after it's
remounted RO due to an abort. There are lots of places that check for
the superblock error bit and will not write data, but we should not let
the filesystem appear read-write.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

This patch makes it possible to set BTRFS_FS_TREE_OBJECTID as the default
subvolume by passing a subvolume id of 0.
Signed-off-by: chandan <chandan@linux.vnet.ibm.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>