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

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

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

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

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

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

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

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

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

Pull two nfsd bugfixes from J. Bruce Fields.

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

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

Pull five Xen bug-fixes from Konrad Rzeszutek Wilk:

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

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

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

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

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

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

Pull IDE fixes from David S. Miller:

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

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

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

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

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

Pull x86 fixes from Ingo Molnar.

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

Pull perf fixes from Ingo Molnar.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

If a file has 3 small extents:

| ext1 | ext2 | ext3 |

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

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

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

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

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

A user reported lots of problems using compression on the new code and it
turns out part of the problem was that igrab() was failing when we added a
new ordered extent.  This is because when writing out an inode under
compression we immediately return without actually doing anything to the
pages, and then in another thread at some point down the line actually do
the ordered dance.  The problem is between the point that we start writeback
and we actually add the ordered extent we could be trying to reclaim the
inode, which makes igrab() return NULL.  So we need to do an igrab() when we
create the async extent and then drop it when we are done with it.  This
makes sure we stay pinned in memory until the ordered extent can get a
reference on it and we are good to go.  With this patch we no longer panic
in btrfs_finish_ordered_io().  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Because btrfs can remove the device that was mounted we need to have a
->show_devname so that in this case we can print out some other device in
the file system to /proc/mount.  So if there are multiple devices in a btrfs
file system we will just print the device with the lowest devid that we can
find.  This will make everything consistent and deal with device removal
properly.  The drawback is if you mount with a device that is higher than
the lowest devicd it won't show up as the mounted device in /proc/mounts,
but this is a small price to pay. This was inspired by Miao Xie's patch.
Thanks,
Reviewed-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <josef@redhat.com>

Al pointed out that we can just toss out the old name on a device and add a
new one arbitrarily, so anybody who uses device->name in printk could
possibly use free'd memory.  Instead of adding locking around all of this he
suggested doing it with RCU, so I've introduced a struct rcu_string that
does just that and have gone through and protected all accesses to
device->name that aren't under the uuid_mutex with rcu_read_lock().  This
protects us and I will use it for dealing with removing the device that we
used to mount the file system in a later patch.  Thanks,
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJosef Bacik <josef@redhat.com>

I was getting hung on umount when a transaction was aborted because a range
of one of the free space inodes was still locked.  This is because the nocow
stuff doesn't unlock anything on error.  This fixed the problem and I
verified that is what was happening.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

So we're forcing the eb's to have their ref count set to 1 so invalidatepage
works but this breaks lots of things, for example root nodes, and is just
plain wrong, we don't need to just evict all of this stuff.  Also drop the
invalidatepage altogether and add a page_cache_release().  With this patch
we no longer hang when trying to access the root nodes after an aborted
transaction and we no longer leak memory.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

If a transaction commit fails we don't abort it so we don't set an error on
the file system.  This patch fixes that by actually calling the abort stuff
and then adding a check for a fs error in the transaction start stuff to
make sure it is caught properly.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

I was getting lots of hung tasks and a NULL pointer dereference because we
are not cleaning up the transaction properly when it aborts.  First we need
to reset the running_transaction to NULL so we don't get a bad dereference
for any start_transaction callers after this.  Also we cannot rely on
waitqueue_active() since it's just a list_empty(), so just call wake_up()
directly since that will do the barrier for us and such.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

The transaction abort stuff was throwing warnings from the list debugging
code because we do a list_del_init outside of the delayed_refs spin lock.
The delayed refs locking makes baby Jesus cry so it's not hard to get wrong,
but we need to take the ref head mutex to make sure it's not being processed
currently, and so if it is we need to drop the spin lock and then take and
drop the mutex and do the search again.  If we can take the mutex then we
can safely remove the head from the list and carry on.  Now when the
transaction aborts I don't get the list debugging warnings.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

While doing my enospc work I got a transaction abortion that resulted in a
panic when we tried to unlock_page() an already unlocked page.  This is
because we aren't calling extent_clear_unlock_delalloc with the locked page
so it was unlocking all the pages in the range.  This is wrong since
__extent_writepage expects to have the page locked still unless we return
*page_started as 1.  This should keep us from panicing.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

TEAC's UD-H01 (and probably other devices) have a gap in the interface
number allocation of their descriptors:

  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          220
    bNumInterfaces          3
    [...]
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      [...]
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         2
      bInterfaceCount         2
      bFunctionClass          1 Audio
      bFunctionSubClass       0
      bFunctionProtocol      32
      iFunction               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      [...]

Once a configuration is selected, usb_set_configuration() walks the
known interfaces of a given configuration and calls find_iad() on
each of them to set the interface association pointer the interface
is included in.

The problem here is that the loop variable is taken for the interface
number in the comparison logic that gathers the association. Which is
fine as long as the descriptors are sane.

In the case above, however, the logic gets out of sync and the
interface association fields of all interfaces beyond the interface
number gap are wrong.

Fix this by passing the interface's bInterfaceNumber to find_iad()
instead.
Signed-off-by: NDaniel Mack <zonque@gmail.com>
Reported-by: NbEN <ml_all@circa.be>
Reported-by: NIvan Perrone <ivanperrone@hotmail.com>
Tested-by: Nivan perrone <ivanperrone@hotmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the platform_data is not set, pdata will be uninitialized value.
Since the driver has the following code, if the condition is true when
the pdata is uninitialized value, the driver may jump to the illegal
phy_init().

	if (pdata && pdata->phy_init)
		pdata->phy_init();

This patch also fixes the following warning:

  CC      drivers/usb/host/ehci-hcd.o
drivers/usb/host/ehci-sh.c: In function ‘ehci_hcd_sh_probe’:
drivers/usb/host/ehci-sh.c:104: warning: ‘pdata’ may be used uninitialized in this function
Signed-off-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently CDC-ACM devices stay throttled when their TTY is closed while
throttled, stalling further communication attempts after the next open.

Unthrottling during open/activate got lost starting with kernel
3.0.0 and this patch reintroduces it.
Signed-off-by: NOtto Meta <otto.patches@sister-shadow.de>
Cc: stable <stable@vger.kernel.org>
Acked-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the frontend and the backend reside on the same domain, even if we
add pages to the m2p_override, these pages will never be returned by
mfn_to_pfn because the check "get_phys_to_machine(pfn) != mfn" will
always fail, so the pfn of the frontend will be returned instead
(resulting in a deadlock because the frontend pages are already locked).

INFO: task qemu-system-i38:1085 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
qemu-system-i38 D ffff8800cfc137c0     0  1085      1 0x00000000
 ffff8800c47ed898 0000000000000282 ffff8800be4596b0 00000000000137c0
 ffff8800c47edfd8 ffff8800c47ec010 00000000000137c0 00000000000137c0
 ffff8800c47edfd8 00000000000137c0 ffffffff82213020 ffff8800be4596b0
Call Trace:
 [<ffffffff81101ee0>] ? __lock_page+0x70/0x70
 [<ffffffff81a0fdd9>] schedule+0x29/0x70
 [<ffffffff81a0fe80>] io_schedule+0x60/0x80
 [<ffffffff81101eee>] sleep_on_page+0xe/0x20
 [<ffffffff81a0e1ca>] __wait_on_bit_lock+0x5a/0xc0
 [<ffffffff81101ed7>] __lock_page+0x67/0x70
 [<ffffffff8106f750>] ? autoremove_wake_function+0x40/0x40
 [<ffffffff811867e6>] ? bio_add_page+0x36/0x40
 [<ffffffff8110b692>] set_page_dirty_lock+0x52/0x60
 [<ffffffff81186021>] bio_set_pages_dirty+0x51/0x70
 [<ffffffff8118c6b4>] do_blockdev_direct_IO+0xb24/0xeb0
 [<ffffffff811e71a0>] ? ext3_get_blocks_handle+0xe00/0xe00
 [<ffffffff8118ca95>] __blockdev_direct_IO+0x55/0x60
 [<ffffffff811e71a0>] ? ext3_get_blocks_handle+0xe00/0xe00
 [<ffffffff811e91c8>] ext3_direct_IO+0xf8/0x390
 [<ffffffff811e71a0>] ? ext3_get_blocks_handle+0xe00/0xe00
 [<ffffffff81004b60>] ? xen_mc_flush+0xb0/0x1b0
 [<ffffffff81104027>] generic_file_aio_read+0x737/0x780
 [<ffffffff813bedeb>] ? gnttab_map_refs+0x15b/0x1e0
 [<ffffffff811038f0>] ? find_get_pages+0x150/0x150
 [<ffffffff8119736c>] aio_rw_vect_retry+0x7c/0x1d0
 [<ffffffff811972f0>] ? lookup_ioctx+0x90/0x90
 [<ffffffff81198856>] aio_run_iocb+0x66/0x1a0
 [<ffffffff811998b8>] do_io_submit+0x708/0xb90
 [<ffffffff81199d50>] sys_io_submit+0x10/0x20
 [<ffffffff81a18d69>] system_call_fastpath+0x16/0x1b

The explanation is in the comment within the code:

We need to do this because the pages shared by the frontend
(xen-blkfront) can be already locked (lock_page, called by
do_read_cache_page); when the userspace backend tries to use them
with direct_IO, mfn_to_pfn returns the pfn of the frontend, so
do_blockdev_direct_IO is going to try to lock the same pages
again resulting in a deadlock.

A simplified call graph looks like this:

pygrub                          QEMU
-----------------------------------------------
do_read_cache_page              io_submit
  |                              |
lock_page                       ext3_direct_IO
                                 |
                                bio_add_page
                                 |
                                lock_page

Internally the xen-blkback uses m2p_add_override to swizzle (temporarily)
a 'struct page' to have a different MFN (so that it can point to another
guest). It also can easily find out whether another pfn corresponding
to the mfn exists in the m2p, and can set the FOREIGN bit
in the p2m, making sure that mfn_to_pfn returns the pfn of the backend.

This allows the backend to perform direct_IO on these pages, but as a
side effect prevents the frontend from using get_user_pages_fast on
them while they are being shared with the backend.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Most frequent symptom was a BUG triggering in expire_client, with the
server locking up shortly thereafter.

Introduced by 508dc6e1 "nfsd41:
free_session/free_client must be called under the client_lock".

Cc: stable@kernel.org
Cc: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

In case of destroying mount namespace on child reaper exit, nsproxy is zeroed
to the point already. So, dereferencing of it is invalid.
This patch hard-code "init_net" for all network namespace references for NFS
callback services. This will be fixed with proper NFS callback
containerization.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>