There is no need for a temporary variable and all the tricks with
ternary operators in acpiphp_get_(latch)|(adapter)_status(). Change
those functions to be a bit more straightforward.

[rjw: Changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Drop some unused symbols from acpiphp.h and redefine SLOT_ENABLED
(which is the only slot flag now) as 1.

[rjw: Redefinition of SLOT_ENABLED, changelog]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The current implementation of acpiphp_check_bridge() is pretty dumb:
 - It enables a slot if it's not enabled and the slot status is
   ACPI_STA_ALL.
 - It disables a slot if it's enabled and the slot status is not
   ACPI_STA_ALL.

This behavior is not sufficient to handle the Thunderbolt daisy
chaining case properly, however, because in that case the bus
behind the already enabled slot needs to be rescanned for new
devices.

For this reason, modify acpiphp_check_bridge() so that slots are
disabled and stopped if they are not in the ACPI_STA_ALL state.

For slots in the ACPI_STA_ALL state, devices behind them that don't
respond are trimmed using a new function, trim_stale_devices(),
introduced specifically for this purpose.  That function walks
the given bus and checks each device on it.  If the device doesn't
respond, it is assumed to be gone and is removed.

Once all of the stale devices directy behind the slot have been
removed, acpiphp_check_bridge() will start looking for new devices
that might have appeared on the given bus.  It will do that even if
the slot is already enabled (SLOT_ENABLED is set for it).

In addition to that, make the bus check notification ignore
SLOT_ENABLED and go for enable_device() directly if bridge is NULL,
so that devices behind the slot are re-enumerated in that case too.

This change is based on earlier patches from Kirill A Shutemov
and Mika Westerberg.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Currently, enable_device() checks the return value of pci_scan_slot()
and returns immediately if that's 0 (meaning that no new functions
have been found in the slot).  However, if one of the functions in
the slot is a bridge, some new devices may appear below it even if
the bridge itself is present continuously, so it generally is
necessary to do the rescan anyway just in case.  [In particular,
that's necessary with the Thunderbolt daisy chaining in which case
new devices may be connected to the existing ones down the chain.]

The correctness of this change relies on the ability of
pcibios_resource_survey_bus() to detect if it has already been called
for the given bus and to skip it if so.  Failure to do that will lead
to resource allocation conflicts.

[rjw: Changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

With Thunderbolt you can daisy chain devices: connect new devices to
an already plugged one.  In that case the "hotplug slot" is already
enabled, but we still want to look for new PCI devices behind it.

Reuse enable_device() to scan for new PCI devices on enabled slots
and push the SLOT_ENABLED check up into acpiphp_enable_slot().

[rjw: Rebased, modified the changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The ACPI-based PCI hotplug (acpiphp) core code need not and really
should not execute _PS0 and _PS3 directly for devices it handles.

First of all, it is not necessary to put devices into D3 after
acpi_bus_trim() has walked through them, because
acpi_device_unregister() invoked by it puts each device into D3cold
before returning.  Thus after disable_device() the slot should be
powered down already.

Second, calling _PS0 directly on ACPI device objects may not be
appropriate, because it may require power resources to be set up in
a specific way in advance and that must be taken care of by the ACPI
core.  Thus modify acpiphp_bus_add() to power up the device using
the appropriate interface after it has run acpi_bus_scan() on its
handle.

After that, the functions executing _PS0 and _PS3, power_on_slot()
and power_off_slot(), are not necessary any more, so drop them
and update the code calling them accordingly.  Also drop the
function flags related to device power states, since they aren't
useful any more too.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Modify handle_hotplug_event() to avoid queing up the execution of
handle_hotplug_event_work_fn() as a work item on kacpi_hotplug_wq
for non-hotplug events, such as ACPI_NOTIFY_DEVICE_WAKE.  Move
the code printing diagnostic messages for those events into
handle_hotplug_event().

In addition to that, remove the bogus comment about how the core
should distinguish between hotplug and non-hotplug events and
queue them up on different workqueues.  The core clearly cannot
know in advance what events will be interesting to the given
caller of acpi_install_notify_handler().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Both acpiphp_disable_slot() and acpiphp_eject_slot() are always
called together so instead of calling each separately we can
consolidate them into one function acpiphp_disable_and_eject_slot()
that does both (but it will return success on _EJ0 failures that
were ignored in the majority of call sites anyway).

[rjw: Rebased plus minor tweaks]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Two checks in check_hotplug_bridge() are redundant (they have been
done by the caller already), so drop them.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The acpiphp_bus_trim() and acpiphp_bus_add() functions need not
return error codes that are never checked, so redefine them and
simplify them a bit.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

To avoid chasing more pointers than necessary in some situations,
move the bridge pointer from struct acpiphp_slot to struct
acpiphp_func (and call it 'parent') and add a bus pointer to
struct acpiphp_slot.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The handle field in struct acpiphp_bridge is only used by
acpiphp_enumerate_slots(), but in that function the local handle
variable can be used instead, so make that happen and drop handle
from struct acpiphp_bridge.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The ACPI handle stored in struct acpiphp_func is also stored in the
struct acpiphp_context object containing it and it is trivial to get
from a struct acpiphp_func pointer to the handle field of the outer
struct acpiphp_context.

Hence, the handle field of struct acpiphp_func is redundant, so drop
it and provide a helper function, func_to_handle(), allowing it
users to get the ACPI handle for the given struct acpiphp_func
pointer.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Since there has to be a struct acpiphp_func object for every struct
acpiphp_context created by register_slot(), the struct acpiphp_func
one can be embedded into the struct acpiphp_context one, which allows
some code simplifications to be made.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The only bridge flag used by the ACPI-based PCI hotplug (ACPIPHP)
code is BRIDGE_HAS_EJ0, but it is only used by the event handling
function hotplug_event() and if that flag is set, the corresponding
function flag FUNC_HAS_EJ0 is set as well, so that bridge flag is
redundant.

For this reason, drop BRIDGE_HAS_EJ0 and all code referring to it
and since it is the only bridge flag defined, drop the flags field
from struct acpiphp_bridge entirely.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

If the slot unique number is passed as an additional argument to
acpiphp_register_hotplug_slot(), the 'sun' field in struct
acpiphp_slot is only used by ibm_[s|g]et_attention_status(),
but then it's more efficient to store it in struct slot.

Thus move the 'sun' field from struct acpiphp_slot to struct slot
changing its data type to unsigned int in the process, and redefine
acpiphp_register_hotplug_slot() to take the slot number as separate
argument.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Rework register_slot() to create a struct acpiphp_func object for
every function it is called for and to create acpiphp slots for all
of them.  Although acpiphp_register_hotplug_slot() is only called for
the slots whose functions are identified as "ejectable", so that user
space can manipulate them, the ACPIPHP notify handler,
handle_hotplug_event(), is now installed for all of the registered
functions (that aren't dock stations) and hotplug events may be
handled for all of them.

As a result, essentially, all PCI bridges represented by objects in
the ACPI namespace are now going to be "hotplug" bridges and that may
affect resources allocation in general, although it shouldn't lead to
problems.

This allows the code to be simplified substantially and addresses
the problem where bus check or device check notifications for some
PCI bridges or devices are not handled, because those devices are
not recognized as "ejectable" or there appear to be no "ejectable"
devices under those bridges.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

To make the code in register_slot() a bit easier to follow, change
the way the slot allocation part is organized.  Drop one local
variable that's not used any more after that modification.

This code change should not lead to any changes in behavior.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Since the func pointer in struct acpiphp_context can always be used
instead of the func pointer in struct acpiphp_bridge, drop the
latter.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

There are separate handling event functions for hotplug bridges and
for hotplug functions, but they may be combined into one common
hotplug event handling function which simplifies the code slightly.

That also allows a theoretical bug to be dealt with which in
principle may occur if a hotplug bridge is on a dock station, because
in that case the bridge-specific notification should be used instead
of the function-specific one, but the dock station always uses the
latter.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Modify handle_hotplug_event() to pass the entire context object
(instead of its fields individually) to work functions started by it.

This change makes the subsequent consolidation of the event handling
work functions a bit more straightforward.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Using the hotplug context objects introduced previously rework the
ACPI-based PCI hotplug (ACPIPHP) core code to get to acpiphp_bridge
objects associated with hotplug bridges from those context objects
rather than from the global list of hotplug bridges.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Using the hotplug context objects introduced previously rework the
ACPI-based PCI hotplug (ACPIPHP) core code so that all notifications
for ACPI device objects corresponding to the hotplug PCI devices are
handled by one function, handle_hotplug_event(), which recognizes
whether it has to handle a bridge or a function.

In addition to code size reduction it allows some ugly pieces of code
where notify handlers have to be uninstalled and installed again to
go away.  Moreover, it fixes a theoretically possible race between
handle_hotplug_event() and free_bridge() tearing down data structures
for the same handle.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

When either a new hotplug bridge or a new hotplug function is added
by the ACPI-based PCI hotplug (ACPIPHP) code, attach a context object
to its ACPI handle to store hotplug-related information in it.  To
start with, put the handle's bridge and function pointers into that
object.  Count references to the context objects and drop them when
they are not needed any more.

First of all, this makes it possible to find out if the given bridge
has been registered as a function already in a much more
straightforward way and acpiphp_bridge_handle_to_function() can be
dropped (Yay!).

This also will allow some more simplifications to be made going
forward.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

When a new ACPIPHP function is added by register_slot() and the
notify handler cannot be installed for it, register_slot() returns an
error status without cleaning up, which causes the entire namespace
walk in acpiphp_enumerate_slots() to be aborted, although it still
may be possible to successfully install the function notify handler
for other device objects under the given brigde.

To address this issue make register_slot() return success after
a new function has been added, even if the addition of the notify
handler for it has failed.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The acpiphp_enumerate_slots() function is now split into two parts,
acpiphp_enumerate_slots() proper and init_bridge_misc() which is
only called by the former.  If these functions are combined,
it is possible to make the code easier to follow and to clean up
the error handling (to prevent memory leaks on error from
happening in particular), so do that.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Since acpi_pci_slot_enumerate() and acpiphp_enumerate_slots() can get
the ACPI device handle they need from bus->bridge, it is not
necessary to pass that handle to them as an argument.

Drop the second argument of acpi_pci_slot_enumerate() and
acpiphp_enumerate_slots(), rework them to obtain the ACPI handle
from bus->bridge and make acpi_pci_add_bus() and
acpi_pci_remove_bus() entirely symmetrical.
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

Subsequent commits depend on the 'acpi-cleanup' material.

In hotplug case (especially with Thunderbolt enabled systems) we might need
to call pcibios_resource_survey_bus() several times for a bus. The function
ends up calling pci_claim_resource() for each bridge resource that then
fails claiming that the resource exists already (which it does). Once this
happens the resource is invalidated thus preventing devices behind the
bridge to allocate their resources.

To fix this we do what has been done in pcibios_allocate_dev_resources()
and check 'parent' of the given resource. If it is non-NULL it means that
the resource has been allocated already and we can skip it. We do the same
for ROM resources as well.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull ACPI video support fixes from Rafael Wysocki:
 "I'm sending a separate pull request for this as it may be somewhat
  controversial.  The breakage addressed here is not really new and the
  fixes may not satisfy all users of the affected systems, but we've had
  so much back and forth dance in this area over the last several weeks
  that I think it's time to actually make some progress.

  The source of the problem is that about a year ago we started to tell
  BIOSes that we're compatible with Windows 8, which we really need to
  do, because some systems shipping with Windows 8 are tested with it
  and nothing else, so if we tell their BIOSes that we aren't compatible
  with Windows 8, we expose our users to untested BIOS/AML code paths.

  However, as it turns out, some Windows 8-specific AML code paths are
  not tested either, because Windows 8 actually doesn't use the ACPI
  methods containing them, so if we declare Windows 8 compatibility and
  attempt to use those ACPI methods, things break.  That occurs mostly
  in the backlight support area where in particular the _BCM and _BQC
  methods are plain unusable on some systems if the OS declares Windows
  8 compatibility.

  [ The additional twist is that they actually become usable if the OS
    says it is not compatible with Windows 8, but that may cause
    problems to show up elsewhere ]

  Investigation carried out by Matthew Garrett indicates that what
  Windows 8 does about backlight is to leave backlight control up to
  individual graphics drivers.  At least there's evidence that it does
  that if the Intel graphics driver is used, so we've decided to follow
  Windows 8 in that respect and allow i915 to control backlight (Daniel
  likes that part).

  The first commit from Aaron Lu makes ACPICA export the variable from
  which we can infer whether or not the BIOS believes that we are
  compatible with Windows 8.

  The second commit from Matthew Garrett prepares the ACPI video driver
  by making it initialize the ACPI backlight even if it is not going to
  be used afterward (that is needed for backlight control to work on
  Thinkpads).

  The third commit implements the actual workaround making i915 take
  over backlight control if the firmware thinks it's dealing with
  Windows 8 and is based on the work of multiple developers, including
  Matthew Garrett, Chun-Yi Lee, Seth Forshee, and Aaron Lu.

  The final commit from Aaron Lu makes us follow Windows 8 by informing
  the firmware through the _DOS method that it should not carry out
  automatic brightness changes, so that brightness can be controlled by
  GUI.

  Hopefully, this approach will allow us to avoid using blacklists of
  systems that should not declare Windows 8 compatibility just to avoid
  backlight control problems in the future.

   - Change from Aaron Lu makes ACPICA export a variable which can be
     used by driver code to determine whether or not the BIOS believes
     that we are compatible with Windows 8.

   - Change from Matthew Garrett makes the ACPI video driver initialize
     the ACPI backlight even if it is not going to be used afterward
     (that is needed for backlight control to work on Thinkpads).

   - Fix from Rafael J Wysocki implements Windows 8 backlight support
     workaround making i915 take over bakclight control if the firmware
     thinks it's dealing with Windows 8.  Based on the work of multiple
     developers including Matthew Garrett, Chun-Yi Lee, Seth Forshee,
     and Aaron Lu.

   - Fix from Aaron Lu makes the kernel follow Windows 8 by informing
     the firmware through the _DOS method that it should not carry out
     automatic brightness changes, so that brightness can be controlled
     by GUI"

* tag 'acpi-video-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: no automatic brightness changes by win8-compatible firmware
  ACPI / video / i915: No ACPI backlight if firmware expects Windows 8
  ACPI / video: Always call acpi_video_init_brightness() on init
  ACPICA: expose OSI version

Pull ext[34] tmpfile bugfix from Ted Ts'o:
 "Fix regression caused by commit af51a2ac which added ->tmpfile()
  support (along with a similar fix for ext3)"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext3: fix a BUG when opening a file with O_TMPFILE flag
  ext4: fix a BUG when opening a file with O_TMPFILE flag

When we try to open a file with O_TMPFILE flag, we will trigger a bug.
The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and
this check always fails because we set ->i_nlink = 1 in
inode_init_always().  We can use the following program to trigger it:

int main(int argc, char *argv[])
{
	int fd;

	fd = open(argv[1], O_TMPFILE, 0666);
	if (fd < 0) {
		perror("open ");
		return -1;
	}
	close(fd);
	return 0;
}

The oops message looks like this:

kernel: kernel BUG at fs/ext3/namei.c:1992!
kernel: invalid opcode: 0000 [#1] SMP
kernel: Modules linked in: ext4 jbd2 crc16 cpufreq_ondemand ipv6 dm_mirror dm_region_hash dm_log dm_mod parport_pc parport serio_raw sg dcdbas pcspkr i2c_i801 ehci_pci ehci_hcd button acpi_cpufreq mperf e1000e ptp pps_core ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core ext3 jbd sd_mod ahci libahci libata scsi_mod uhci_hcd
kernel: CPU: 0 PID: 2882 Comm: tst_tmpfile Not tainted 3.11.0-rc1+ #4
kernel: Hardware name: Dell Inc. OptiPlex 780 /0V4W66, BIOS A05 08/11/2010
kernel: task: ffff880112d30050 ti: ffff8801124d4000 task.ti: ffff8801124d4000
kernel: RIP: 0010:[<ffffffffa00db5ae>] [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3]
kernel: RSP: 0018:ffff8801124d5cc8  EFLAGS: 00010202
kernel: RAX: 0000000000000000 RBX: ffff880111510128 RCX: ffff8801114683a0
kernel: RDX: 0000000000000000 RSI: ffff880111510128 RDI: ffff88010fcf65a8
kernel: RBP: ffff8801124d5d18 R08: 0080000000000000 R09: ffffffffa00d3b7f
kernel: R10: ffff8801114683a0 R11: ffff8801032a2558 R12: 0000000000000000
kernel: R13: ffff88010fcf6800 R14: ffff8801032a2558 R15: ffff8801115100d8
kernel: FS:  00007f5d172b5700(0000) GS:ffff880117c00000(0000) knlGS:0000000000000000
kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
kernel: CR2: 00007f5d16df15d0 CR3: 0000000110b1d000 CR4: 00000000000407f0
kernel: Stack:
kernel: 000000000000000c ffff8801048a7dc8 ffff8801114685a8 ffffffffa00b80d7
kernel: ffff8801124d5e38 ffff8801032a2558 ffff88010ce24d68 0000000000000000
kernel: ffff88011146b300 ffff8801124d5d44 ffff8801124d5d78 ffffffffa00db7e1
kernel: Call Trace:
kernel: [<ffffffffa00b80d7>] ? journal_start+0x8c/0xbd [jbd]
kernel: [<ffffffffa00db7e1>] ext3_tmpfile+0xb2/0x13b [ext3]
kernel: [<ffffffff821076f8>] path_openat+0x11f/0x5e7
kernel: [<ffffffff821c86b4>] ? list_del+0x11/0x30
kernel: [<ffffffff82065fa2>] ?  __dequeue_entity+0x33/0x38
kernel: [<ffffffff82107cd5>] do_filp_open+0x3f/0x8d
kernel: [<ffffffff82112532>] ? __alloc_fd+0x50/0x102
kernel: [<ffffffff820f9296>] do_sys_open+0x13b/0x1cd
kernel: [<ffffffff820f935c>] SyS_open+0x1e/0x20
kernel: [<ffffffff82398c02>] system_call_fastpath+0x16/0x1b
kernel: Code: 39 c7 0f 85 67 01 00 00 0f b7 03 25 00 f0 00 00 3d 00 40 00 00 74 18 3d 00 80 00 00 74 11 3d 00 a0 00 00 74 0a 83 7b 48 00 74 04 <0f> 0b eb fe 49 8b 85 50 03 00 00 4c 89 f6 48 c7 c7 c0 99 0e a0
kernel: RIP  [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3]
kernel: RSP <ffff8801124d5cc8>

Here we couldn't call clear_nlink() directly because in d_tmpfile() we
will call inode_dec_link_count() to decrease ->i_nlink.  So this commit
tries to call d_tmpfile() before ext4_orphan_add() to fix this problem.
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>

When we try to open a file with O_TMPFILE flag, we will trigger a bug.
The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and
this check always fails because we set ->i_nlink = 1 in
inode_init_always().  We can use the following program to trigger it:

int main(int argc, char *argv[])
{
	int fd;

	fd = open(argv[1], O_TMPFILE, 0666);
	if (fd < 0) {
		perror("open ");
		return -1;
	}
	close(fd);
	return 0;
}

The oops message looks like this:

kernel BUG at fs/ext4/namei.c:2572!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: dlci bridge stp hidp cmtp kernelcapi l2tp_ppp l2tp_netlink l2tp_core sctp libcrc32c rfcomm tun fuse nfnetli
nk can_raw ipt_ULOG can_bcm x25 scsi_transport_iscsi ipx p8023 p8022 appletalk phonet psnap vmw_vsock_vmci_transport af_key vmw_vmci rose vsock atm can netrom ax25 af_rxrpc ir
da pppoe pppox ppp_generic slhc bluetooth nfc rfkill rds caif_socket caif crc_ccitt af_802154 llc2 llc snd_hda_codec_realtek snd_hda_intel snd_hda_codec serio_raw snd_pcm pcsp
kr edac_core snd_page_alloc snd_timer snd soundcore r8169 mii sr_mod cdrom pata_atiixp radeon backlight drm_kms_helper ttm
CPU: 1 PID: 1812571 Comm: trinity-child2 Not tainted 3.11.0-rc1+ #12
Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010
task: ffff88007dfe69a0 ti: ffff88010f7b6000 task.ti: ffff88010f7b6000
RIP: 0010:[<ffffffff8125ce69>]  [<ffffffff8125ce69>] ext4_orphan_add+0x299/0x2b0
RSP: 0018:ffff88010f7b7cf8  EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff8800966d3020 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88007dfe70b8 RDI: 0000000000000001
RBP: ffff88010f7b7d40 R08: ffff880126a3c4e0 R09: ffff88010f7b7ca0
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801271fd668
R13: ffff8800966d2f78 R14: ffff88011d7089f0 R15: ffff88007dfe69a0
FS:  00007f70441a3740(0000) GS:ffff88012a800000(0000) knlGS:00000000f77c96c0
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000002834000 CR3: 0000000107964000 CR4: 00000000000007e0
DR0: 0000000000780000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Stack:
 0000000000002000 00000020810b6dde 0000000000000000 ffff88011d46db00
 ffff8800966d3020 ffff88011d7089f0 ffff88009c7f4c10 ffff88010f7b7f2c
 ffff88007dfe69a0 ffff88010f7b7da8 ffffffff8125cfac ffff880100000004
Call Trace:
 [<ffffffff8125cfac>] ext4_tmpfile+0x12c/0x180
 [<ffffffff811cba78>] path_openat+0x238/0x700
 [<ffffffff8100afc4>] ? native_sched_clock+0x24/0x80
 [<ffffffff811cc647>] do_filp_open+0x47/0xa0
 [<ffffffff811db73f>] ? __alloc_fd+0xaf/0x200
 [<ffffffff811ba2e4>] do_sys_open+0x124/0x210
 [<ffffffff81010725>] ? syscall_trace_enter+0x25/0x290
 [<ffffffff811ba3ee>] SyS_open+0x1e/0x20
 [<ffffffff816ca8d4>] tracesys+0xdd/0xe2
 [<ffffffff81001001>] ? start_thread_common.constprop.6+0x1/0xa0
Code: 04 00 00 00 89 04 24 31 c0 e8 c4 77 04 00 e9 43 fe ff ff 66 25 00 d0 66 3d 00 80 0f 84 0e fe ff ff 83 7b 48 00 0f 84 04 fe ff ff <0f> 0b 49 8b 8c 24 50 07 00 00 e9 88 fe ff ff 0f 1f 84 00 00 00

Here we couldn't call clear_nlink() directly because in d_tmpfile() we
will call inode_dec_link_count() to decrease ->i_nlink.  So this commit
tries to call d_tmpfile() before ext4_orphan_add() to fix this problem.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Tested-by: Darrick J. Wong <darrick.wong@oracle.com>
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>

Pull staging tree fixes from Greg KH:
 "Here are a few iio driver fixes for 3.11-rc2.  They are still spread
  across drivers/iio and drivers/staging/iio so they are coming in
  through this tree.

  I've also removed the drivers/staging/csr/ driver as the developers
  who originally sent it to me have moved on to other companies, and CSR
  still will not send us the specs for the device, making the driver
  pretty much obsolete and impossible to fix up.  Deleting it now
  prevents people from sending in lots of tiny codingsyle fixes that
  will never go anywhere.

  It also helps to offset the large lustre filesystem merge that
  happened in 3.11-rc1 in the overall 3.11.0 diffstat.  :)"

* tag 'staging-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: csr: remove driver
  iio: lps331ap: Fix wrong in_pressure_scale output value
  iio staging: fix lis3l02dq, read error handling
  staging:iio:ad7291: add missing .driver_module to struct iio_info
  iio: ti_am335x_adc: add missing .driver_module to struct iio_info
  iio: mxs-lradc: Remove useless check in read_raw
  iio: mxs-lradc: Fix misuse of iio->trig
  iio: inkern: fix iio_convert_raw_to_processed_unlocked
  iio: Fix iio_channel_has_info
  iio:trigger: device_unregister->device_del to avoid double free
  iio: dac: ad7303: fix error return code in ad7303_probe()

Pull vfs fixes from Al Viro:
 "The sget() one is a long-standing bug and will need to go into -stable
  (in fact, it had been originally caught in RHEL6), the other two are
  3.11-only"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: constify dentry parameter in d_count()
  livelock avoidance in sget()
  allow O_TMPFILE to work with O_WRONLY

Pull ext4 bugfixes from Ted Ts'o:
 "Fixes for 3.11-rc2, sent at 5pm, in the professoinal style.  :-)"

I'm not sure I like this new level of "professionalism".
9-5, people, 9-5.

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: call ext4_es_lru_add() after handling cache miss
  ext4: yield during large unlinks
  ext4: make the extent_status code more robust against ENOMEM failures
  ext4: simplify calculation of blocks to free on error
  ext4: fix error handling in ext4_ext_truncate()

Pull NFS client bugfixes from Trond Myklebust:
 - Fix a regression against NFSv4 FreeBSD servers when creating a new
   file
 - Fix another regression in rpc_client_register()

* tag 'nfs-for-3.11-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4: Fix a regression against the FreeBSD server
  SUNRPC: Fix another issue with rpc_client_register()

Pull btrfs fixes from Josef Bacik:
 "I'm playing the role of Chris Mason this week while he's on vacation.
  There are a few critical fixes for btrfs here, all regressions and
  have been tested well"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next:
  Btrfs: fix wrong write offset when replacing a device
  Btrfs: re-add root to dead root list if we stop dropping it
  Btrfs: fix lock leak when resuming snapshot deletion
  Btrfs: update drop progress before stopping snapshot dropping

so that it can be used in places like d_compare/d_hash
without causing a compiler warning.
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>