commit fc57a7c6 upstream.

PARAVIRT_ADJUST_EXCEPTION_FRAME generates this code (using nmi as an
example, trimmed for readability):

    ff 15 00 00 00 00       callq  *0x0(%rip)        # 2796 <nmi+0x6>
              2792: R_X86_64_PC32     pv_irq_ops+0x2c

That's a call through a function pointer to regular C function that
does nothing on native boots, but that function isn't protected
against kprobes, isn't marked notrace, and is certainly not
guaranteed to preserve any registers if the compiler is feeling
perverse.  This is bad news for a CLBR_NONE operation.

Of course, if everything works correctly, once paravirt ops are
patched, it gets nopped out, but what if we hit this code before
paravirt ops are patched in?  This can potentially cause breakage
that is very difficult to debug.

A more subtle failure is possible here, too: if _paravirt_nop uses
the stack at all (even just to push RBP), it will overwrite the "NMI
executing" variable if it's called in the NMI prologue.

The Xen case, perhaps surprisingly, is fine, because it's already
written in asm.

Fix all of the cases that default to paravirt_nop (including
adjust_exception_frame) with a big hammer: replace paravirt_nop with
an asm function that is just a ret instruction.

The Xen case may have other problems, so document them.

This is part of a fix for some random crashes that Sasha saw.
Reported-and-tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Link: http://lkml.kernel.org/r/8f5d2ba295f9d73751c33d97fda03e0495d9ade0.1442791737.git.luto@kernel.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 98ce94c8 upstream.

Linux cifs mount with ntlmssp against an Mac OS X (Yosemite
10.10.5) share fails in case the clocks differ more than +/-2h:

digest-service: digest-request: od failed with 2 proto=ntlmv2
digest-service: digest-request: kdc failed with -1561745592 proto=ntlmv2

Fix this by (re-)using the given server timestamp for the
ntlmv2 authentication (as Windows 7 does).

A related problem was also reported earlier by Namjae Jaen (see below):

Windows machine has extended security feature which refuse to allow
authentication when there is time difference between server time and
client time when ntlmv2 negotiation is used. This problem is prevalent
in embedded enviornment where system time is set to default 1970.

Modern servers send the server timestamp in the TargetInfo Av_Pair
structure in the challenge message [see MS-NLMP 2.2.2.1]
In [MS-NLMP 3.1.5.1.2] it is explicitly mentioned that the client must
use the server provided timestamp if present OR current time if it is
not
Reported-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Steve French <smfrench@gmail.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit dca77945 upstream.

Some changes between xhci 0.96 and xhci 1.0 specifications forced us to
check the hci version in code, some of these checks were implemented as
hci_version == 1.0, which will not work with new xhci 1.1 controllers.

xhci 1.1 behaves similar to xhci 1.0 in these cases, so change these
checks to hci_version >= 1.0
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit e5bfeab0 upstream.

For whatever reason if XHCI died in the previous instant
then it will never recover on the next xhci_start unless we
clear the DYING flag.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit a6809ffd upstream.

We want to give the command abortion an additional try to stop
the command ring before we completely hose xhci.
Tested-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: call handshake() rather than xhci_handshake()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit ff30cbc8 upstream.

Bits 1:0 of the bmAttributes are used for the burst multiplier.
The rest of the bits used to be reserved (zero), but USB3.1 takes bit 7
into use.

Use the existing USB_SS_MULT() macro instead to make sure the mult value
and hence max packet calculations are correct for USB3.1 devices.

Note that burst multiplier in bmAttributes is zero based and that
the USB_SS_MULT() macro adds one.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 3afb1121 upstream.

These have roughly the same purpose as the SMRR, which we do not need
to implement in KVM.  However, Linux accesses MSR_K8_TSEG_ADDR at
boot, which causes problems when running a Xen dom0 under KVM.
Just return 0, meaning that processor protection of SMRAM is not
in effect.
Reported-by: M A Young <m.a.young@durham.ac.uk>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 8d4bd0ed upstream.

The uc_sigmask in the ucontext structure is an array of words to keep
the 64 signal bits (or 1024 if you ask glibc but the kernel sigset_t
only has 64 bits).

For 64 bit the sigset_t contains a single 8 byte word, but for 31 bit
there are two 4 byte words. The compat signal handler code uses a
simple copy of the 64 bit sigset_t to the 31 bit compat_sigset_t.
As s390 is a big-endian architecture this is incorrect, the two words
in the 31 bit sigset_t array need to be swapped.
Reported-by: Stefan Liebler <stli@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[bwh: Backported to 3.2:
 - Introduce local compat_sigset_t in setup_frame32()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 3c8f7710 upstream.

The previous fix of pxa library support, which was introduced to fix the
library dependency, broke the previous SoC behavior, where a machine
code binding pxa2xx-ac97 with a coded relied on :
 - sound/soc/pxa/pxa2xx-ac97.c
 - sound/soc/codecs/XXX.c

For example, the mioa701_wm9713.c machine code is currently broken. The
"select ARM" statement wrongly selects the soc/arm/pxa2xx-ac97 for
compilation, as per an unfortunate fate SND_PXA2XX_AC97 is both declared
in sound/arm/Kconfig and sound/soc/pxa/Kconfig.

Fix this by ensuring that SND_PXA2XX_SOC correctly triggers the correct
pxa2xx-ac97 compilation.

Fixes: 846172df ("ASoC: fix SND_PXA2XX_LIB Kconfig warning")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 03da3ff1 upstream.

In 2007, commit 07190a08 ("Mark TSC on GeodeLX reliable")
bypassed verification of the TSC on Geode LX. However, this code
(now in the check_system_tsc_reliable() function in
arch/x86/kernel/tsc.c) was only present if CONFIG_MGEODE_LX was
set.

OpenWRT has recently started building its generic Geode target
for Geode GX, not LX, to include support for additional
platforms. This broke the timekeeping on LX-based devices,
because the TSC wasn't marked as reliable:
https://dev.openwrt.org/ticket/20531

By adding a runtime check on is_geode_lx(), we can also include
the fix if CONFIG_MGEODEGX1 or CONFIG_X86_GENERIC are set, thus
fixing the problem.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: Andres Salomon <dilinger@queued.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marcelo Tosatti <marcelo@kvack.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1442409003.131189.87.camel@infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 9b55613f upstream.

When a kernel is built covering ARMv6 to ARMv7, we omit to clear the
IT state when entering a signal handler.  This can cause the first
few instructions to be conditionally executed depending on the parent
context.

In any case, the original test for >= ARMv7 is broken - ARMv6 can have
Thumb-2 support as well, and an ARMv6T2 specific build would omit this
code too.

Relax the test back to ARMv6 or greater.  This results in us always
clearing the IT state bits in the PSR, even on CPUs where these bits
are reserved.  However, they're reserved for the IT state, so this
should cause no harm.

Fixes: d71e1352 ("Clear the IT state when invoking a Thumb-2 signal handler")
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: H. Nikolaus Schaller <hns@goldelico.com>
Tested-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 6ecf830e upstream.

The ARM architecture reference specifies that the IT state bits in the
PSR must be all zeros in ARM mode or behavior is unspecified.  On the
Qualcomm Snapdragon S4/Krait architecture CPUs the processor continues
to consider the IT state bits while in ARM mode.  This makes it so
that some instructions are skipped by the CPU.
Signed-off-by: T.J. Purtell <tj@mobisocial.us>
[rmk+kernel@arm.linux.org.uk: fixed whitespace formatting in patch]
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit a30e577c upstream.

In btrfs_evict_inode, we properly truncate the page cache for evicted
inodes but then we call btrfs_wait_ordered_range for every inode as well.
It's the right thing to do for regular files but results in incorrect
behavior for device inodes for block devices.

filemap_fdatawrite_range gets called with inode->i_mapping which gets
resolved to the block device inode before getting passed to
wbc_attach_fdatawrite_inode and ultimately to inode_to_bdi.  What happens
next depends on whether there's an open file handle associated with the
inode.  If there is, we write to the block device, which is unexpected
behavior.  If there isn't, we through normally and inode->i_data is used.
We can also end up racing against open/close which can result in crashes
when i_mapping points to a block device inode that has been closed.

Since there can't be any page cache associated with special file inodes,
it's safe to skip the btrfs_wait_ordered_range call entirely and avoid
the problem.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=100911Tested-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 005efedf upstream.

If a file has a range pointing to a compressed extent, followed by
another range that points to the same compressed extent and a read
operation attempts to read both ranges (either completely or part of
them), the pages that correspond to the second range are incorrectly
filled with zeroes.

Consider the following example:

  File layout
  [0 - 8K]                      [8K - 24K]
      |                             |
      |                             |
   points to extent X,         points to extent X,
   offset 4K, length of 8K     offset 0, length 16K

  [extent X, compressed length = 4K uncompressed length = 16K]

If a readpages() call spans the 2 ranges, a single bio to read the extent
is submitted - extent_io.c:submit_extent_page() would only create a new
bio to cover the second range pointing to the extent if the extent it
points to had a different logical address than the extent associated with
the first range. This has a consequence of the compressed read end io
handler (compression.c:end_compressed_bio_read()) finish once the extent
is decompressed into the pages covering the first range, leaving the
remaining pages (belonging to the second range) filled with zeroes (done
by compression.c:btrfs_clear_biovec_end()).

So fix this by submitting the current bio whenever we find a range
pointing to a compressed extent that was preceded by a range with a
different extent map. This is the simplest solution for this corner
case. Making the end io callback populate both ranges (or more, if we
have multiple pointing to the same extent) is a much more complex
solution since each bio is tightly coupled with a single extent map and
the extent maps associated to the ranges pointing to the shared extent
can have different offsets and lengths.

The following test case for fstests triggers the issue:

  seq=`basename $0`
  seqres=$RESULT_DIR/$seq
  echo "QA output created by $seq"
  tmp=/tmp/$$
  status=1	# failure is the default!
  trap "_cleanup; exit \$status" 0 1 2 3 15

  _cleanup()
  {
      rm -f $tmp.*
  }

  # get standard environment, filters and checks
  . ./common/rc
  . ./common/filter

  # real QA test starts here
  _need_to_be_root
  _supported_fs btrfs
  _supported_os Linux
  _require_scratch
  _require_cloner

  rm -f $seqres.full

  test_clone_and_read_compressed_extent()
  {
      local mount_opts=$1

      _scratch_mkfs >>$seqres.full 2>&1
      _scratch_mount $mount_opts

      # Create a test file with a single extent that is compressed (the
      # data we write into it is highly compressible no matter which
      # compression algorithm is used, zlib or lzo).
      $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K"        \
                      -c "pwrite -S 0xbb 4K 8K"        \
                      -c "pwrite -S 0xcc 12K 4K"       \
                      $SCRATCH_MNT/foo | _filter_xfs_io

      # Now clone our extent into an adjacent offset.
      $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \
          $SCRATCH_MNT/foo $SCRATCH_MNT/foo

      # Same as before but for this file we clone the extent into a lower
      # file offset.
      $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K"         \
                      -c "pwrite -S 0xbb 12K 8K"        \
                      -c "pwrite -S 0xcc 20K 4K"        \
                      $SCRATCH_MNT/bar | _filter_xfs_io

      $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \
          $SCRATCH_MNT/bar $SCRATCH_MNT/bar

      echo "File digests before unmounting filesystem:"
      md5sum $SCRATCH_MNT/foo | _filter_scratch
      md5sum $SCRATCH_MNT/bar | _filter_scratch

      # Evicting the inode or clearing the page cache before reading
      # again the file would also trigger the bug - reads were returning
      # all bytes in the range corresponding to the second reference to
      # the extent with a value of 0, but the correct data was persisted
      # (it was a bug exclusively in the read path). The issue happened
      # only if the same readpages() call targeted pages belonging to the
      # first and second ranges that point to the same compressed extent.
      _scratch_remount

      echo "File digests after mounting filesystem again:"
      # Must match the same digests we got before.
      md5sum $SCRATCH_MNT/foo | _filter_scratch
      md5sum $SCRATCH_MNT/bar | _filter_scratch
  }

  echo -e "\nTesting with zlib compression..."
  test_clone_and_read_compressed_extent "-o compress=zlib"

  _scratch_unmount

  echo -e "\nTesting with lzo compression..."
  test_clone_and_read_compressed_extent "-o compress=lzo"

  status=0
  exit
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
[bwh: Backported to 3.2:
 - Maintain prev_em_start in both functions calling __extent_read_full_page()
   in a loop
 - Adjust context and order]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 19ab6bc5 upstream.

This is intended to add ZTE device PIDs on kernel.
Signed-off-by: Liu.Zhao <lzsos369@163.com>
[johan: sort the new entries ]
Signed-off-by: Johan Hovold <johan@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit caa47047 upstream.

The original patch introducing this header wrote the number of CPUs available
and online in one order and then swapped those values when reading, fix it.

Before:

  # perf record usleep 1
  # perf report --header-only | grep 'nrcpus \(online\|avail\)'
  # nrcpus online : 4
  # nrcpus avail : 4
  # echo 0 > /sys/devices/system/cpu/cpu2/online
  # perf record usleep 1
  # perf report --header-only | grep 'nrcpus \(online\|avail\)'
  # nrcpus online : 4
  # nrcpus avail : 3
  # echo 0 > /sys/devices/system/cpu/cpu1/online
  # perf record usleep 1
  # perf report --header-only | grep 'nrcpus \(online\|avail\)'
  # nrcpus online : 4
  # nrcpus avail : 2

After the fix, bringing back the CPUs online:

  # perf report --header-only | grep 'nrcpus \(online\|avail\)'
  # nrcpus online : 2
  # nrcpus avail : 4
  # echo 1 > /sys/devices/system/cpu/cpu2/online
  # perf record usleep 1
  # perf report --header-only | grep 'nrcpus \(online\|avail\)'
  # nrcpus online : 3
  # nrcpus avail : 4
  # echo 1 > /sys/devices/system/cpu/cpu1/online
  # perf record usleep 1
  # perf report --header-only | grep 'nrcpus \(online\|avail\)'
  # nrcpus online : 4
  # nrcpus avail : 4
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: fbe96f29 ("perf tools: Make perf.data more self-descriptive (v8)")
Link: http://lkml.kernel.org/r/20150911153323.GP23511@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[bwh: Backported to 3.2: print_nrcpus() reads and prints these fields
 immediately, so read both of them into an array before printing them in
 reverse order.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit b4cc0efe upstream.

Fix B-tree corruption when a new record is inserted at position 0 in the
node in hfs_brec_insert().

This is an identical change to the corresponding hfs b-tree code to Sergei
Antonov's "hfsplus: fix B-tree corruption after insertion at position 0",
to keep similar code paths in the hfs and hfsplus drivers in sync, where
appropriate.
Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Sergei Antonov <saproj@gmail.com>
Cc: Joe Perches <joe@perches.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 7cb74be6 upstream.

Pages looked up by __hfs_bnode_create() (called by hfs_bnode_create() and
hfs_bnode_find() for finding or creating pages corresponding to an inode)
are immediately kmap()'ed and used (both read and write) and kunmap()'ed,
and should not be page_cache_release()'ed until hfs_bnode_free().

This patch fixes a problem I first saw in July 2012: merely running "du"
on a large hfsplus-mounted directory a few times on a reasonably loaded
system would get the hfsplus driver all confused and complaining about
B-tree inconsistencies, and generates a "BUG: Bad page state".  Most
recently, I can generate this problem on up-to-date Fedora 22 with shipped
kernel 4.0.5, by running "du /" (="/" + "/home" + "/mnt" + other smaller
mounts) and "du /mnt" simultaneously on two windows, where /mnt is a
lightly-used QEMU VM image of the full Mac OS X 10.9:

$ df -i / /home /mnt
Filesystem                  Inodes   IUsed      IFree IUse% Mounted on
/dev/mapper/fedora-root    3276800  551665    2725135   17% /
/dev/mapper/fedora-home   52879360  716221   52163139    2% /home
/dev/nbd0p2             4294967295 1387818 4293579477    1% /mnt

After applying the patch, I was able to run "du /" (60+ times) and "du
/mnt" (150+ times) continuously and simultaneously for 6+ hours.

There are many reports of the hfsplus driver getting confused under load
and generating "BUG: Bad page state" or other similar issues over the
years.  [1]

The unpatched code [2] has always been wrong since it entered the kernel
tree.  The only reason why it gets away with it is that the
kmap/memcpy/kunmap follow very quickly after the page_cache_release() so
the kernel has not had a chance to reuse the memory for something else,
most of the time.

The current RW driver appears to have followed the design and development
of the earlier read-only hfsplus driver [3], where-by version 0.1 (Dec
2001) had a B-tree node-centric approach to
read_cache_page()/page_cache_release() per bnode_get()/bnode_put(),
migrating towards version 0.2 (June 2002) of caching and releasing pages
per inode extents.  When the current RW code first entered the kernel [2]
in 2005, there was an REF_PAGES conditional (and "//" commented out code)
to switch between B-node centric paging to inode-centric paging.  There
was a mistake with the direction of one of the REF_PAGES conditionals in
__hfs_bnode_create().  In a subsequent "remove debug code" commit [4], the
read_cache_page()/page_cache_release() per bnode_get()/bnode_put() were
removed, but a page_cache_release() was mistakenly left in (propagating
the "REF_PAGES <-> !REF_PAGE" mistake), and the commented-out
page_cache_release() in bnode_release() (which should be spanned by
!REF_PAGES) was never enabled.

References:
[1]:
Michael Fox, Apr 2013
http://www.spinics.net/lists/linux-fsdevel/msg63807.html
("hfsplus volume suddenly inaccessable after 'hfs: recoff %d too large'")

Sasha Levin, Feb 2015
http://lkml.org/lkml/2015/2/20/85 ("use after free")

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740814
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1027887
https://bugzilla.kernel.org/show_bug.cgi?id=42342
https://bugzilla.kernel.org/show_bug.cgi?id=63841
https://bugzilla.kernel.org/show_bug.cgi?id=78761

[2]:
http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\
fs/hfs/bnode.c?id=d1081202
commit d1081202
Author: Andrew Morton <akpm@osdl.org>
Date:   Wed Feb 25 16:17:36 2004 -0800

    [PATCH] HFS rewrite

http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\
fs/hfsplus/bnode.c?id=91556682

commit 91556682
Author: Andrew Morton <akpm@osdl.org>
Date:   Wed Feb 25 16:17:48 2004 -0800

    [PATCH] HFS+ support

[3]:
http://sourceforge.net/projects/linux-hfsplus/

http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.1/
http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.2/

http://linux-hfsplus.cvs.sourceforge.net/viewvc/linux-hfsplus/linux/\
fs/hfsplus/bnode.c?r1=1.4&r2=1.5

Date:   Thu Jun 6 09:45:14 2002 +0000
Use buffer cache instead of page cache in bnode.c. Cache inode extents.

[4]:
http://git.kernel.org/cgit/linux/kernel/git/\
stable/linux-stable.git/commit/?id=a5e3985f

commit a5e3985f
Author: Roman Zippel <zippel@linux-m68k.org>
Date:   Tue Sep 6 15:18:47 2005 -0700

[PATCH] hfs: remove debug code
Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Anton Altaparmakov <anton@tuxera.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Sougata Santra <sougata@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit e297c939 upstream.

This fixes a race which can result in the same virtual IRQ number
being assigned to two different MSI interrupts.  The most visible
consequence of that is usually a warning and stack trace from the
sysfs code about an attempt to create a duplicate entry in sysfs.

The race happens when one CPU (say CPU 0) is disposing of an MSI
while another CPU (say CPU 1) is setting up an MSI.  CPU 0 calls
(for example) pnv_teardown_msi_irqs(), which calls
msi_bitmap_free_hwirqs() to indicate that the MSI (i.e. its
hardware IRQ number) is no longer in use.  Then, before CPU 0 gets
to calling irq_dispose_mapping() to free up the virtal IRQ number,
CPU 1 comes in and calls msi_bitmap_alloc_hwirqs() to allocate an
MSI, and gets the same hardware IRQ number that CPU 0 just freed.
CPU 1 then calls irq_create_mapping() to get a virtual IRQ number,
which sees that there is currently a mapping for that hardware IRQ
number and returns the corresponding virtual IRQ number (which is
the same virtual IRQ number that CPU 0 was using).  CPU 0 then
calls irq_dispose_mapping() and frees that virtual IRQ number.
Now, if another CPU comes along and calls irq_create_mapping(), it
is likely to get the virtual IRQ number that was just freed,
resulting in the same virtual IRQ number apparently being used for
two different hardware interrupts.

To fix this race, we just move the call to msi_bitmap_free_hwirqs()
to after the call to irq_dispose_mapping().  Since virq_to_hw()
doesn't work for the virtual IRQ number after irq_dispose_mapping()
has been called, we need to call it before irq_dispose_mapping() and
remember the result for the msi_bitmap_free_hwirqs() call.

The pattern of calling msi_bitmap_free_hwirqs() before
irq_dispose_mapping() appears in 5 places under arch/powerpc, and
appears to have originated in commit 05af7bd2 ("[POWERPC] MPIC
U3/U4 MSI backend") from 2007.

Fixes: 05af7bd2 ("[POWERPC] MPIC U3/U4 MSI backend")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[bwh: Backported to 3.2:
 - powernv uses a private functions instead of msi_bitmap_free_hwirqs()
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 1c90308e upstream.

This patch makes pagemap readable for normal users and hides physical
addresses from them.  For some use-cases PFN isn't required at all.

See http://lkml.kernel.org/r/1425935472-17949-1-git-send-email-kirill@shutemov.name

Fixes: ab676b7d ("pagemap: do not leak physical addresses to non-privileged userspace")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Mark Williamson <mwilliamson@undo-software.com>
Tested-by: Mark Williamson <mwilliamson@undo-software.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
 - Add the same check in the places where we look up a PFN
 - Add struct pagemapread * parameters where necessary
 - Open-code file_ns_capable()
 - Delete pagemap_open() entirely, as it would always return 0]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit a077224f upstream.

While working on the 32-bit ARM port of UEFI, I noticed a strange
corruption in the kernel log. The following snprintf() statement
(in drivers/firmware/efi/efi.c:efi_md_typeattr_format())

	snprintf(pos, size, "|%3s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]",

was producing the following output in the log:

	|    |   |   |   |    |WB|WT|WC|UC]
	|    |   |   |   |    |WB|WT|WC|UC]
	|    |   |   |   |    |WB|WT|WC|UC]
	|RUN|   |   |   |    |WB|WT|WC|UC]*
	|RUN|   |   |   |    |WB|WT|WC|UC]*
	|    |   |   |   |    |WB|WT|WC|UC]
	|RUN|   |   |   |    |WB|WT|WC|UC]*
	|    |   |   |   |    |WB|WT|WC|UC]
	|RUN|   |   |   |    |   |   |   |UC]
	|RUN|   |   |   |    |   |   |   |UC]

As it turns out, this is caused by incorrect code being emitted for
the string() function in lib/vsprintf.c. The following code

	if (!(spec.flags & LEFT)) {
		while (len < spec.field_width--) {
			if (buf < end)
				*buf = ' ';
			++buf;
		}
	}
	for (i = 0; i < len; ++i) {
		if (buf < end)
			*buf = *s;
		++buf; ++s;
	}
	while (len < spec.field_width--) {
		if (buf < end)
			*buf = ' ';
		++buf;
	}

when called with len == 0, triggers an issue in the GCC SRA optimization
pass (Scalar Replacement of Aggregates), which handles promotion of signed
struct members incorrectly. This is a known but as yet unresolved issue.
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65932). In this particular
case, it is causing the second while loop to be executed erroneously a
single time, causing the additional space characters to be printed.

So disable the optimization by passing -fno-ipa-sra.
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit a068acf2 upstream.

Many file systems that implement the show_options hook fail to correctly
escape their output which could lead to unescaped characters (e.g.  new
lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files.  This
could lead to confusion, spoofed entries (resulting in things like
systemd issuing false d-bus "mount" notifications), and who knows what
else.  This looks like it would only be the root user stepping on
themselves, but it's possible weird things could happen in containers or
in other situations with delegated mount privileges.

Here's an example using overlay with setuid fusermount trusting the
contents of /proc/mounts (via the /etc/mtab symlink).  Imagine the use
of "sudo" is something more sneaky:

  $ BASE="ovl"
  $ MNT="$BASE/mnt"
  $ LOW="$BASE/lower"
  $ UP="$BASE/upper"
  $ WORK="$BASE/work/ 0 0
  none /proc fuse.pwn user_id=1000"
  $ mkdir -p "$LOW" "$UP" "$WORK"
  $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt
  $ cat /proc/mounts
  none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0
  none /proc fuse.pwn user_id=1000 0 0
  $ fusermount -u /proc
  $ cat /proc/mounts
  cat: /proc/mounts: No such file or directory

This fixes the problem by adding new seq_show_option and
seq_show_option_n helpers, and updating the vulnerable show_option
handlers to use them as needed.  Some, like SELinux, need to be open
coded due to unusual existing escape mechanisms.

[akpm@linux-foundation.org: add lost chunk, per Kees]
[keescook@chromium.org: seq_show_option should be using const parameters]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Jan Kara <jack@suse.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: J. R. Okajima <hooanon05g@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
 - Drop changes to overlayfs, reiserfs
 - Drop vers option from cifs
 - ceph changes are all in one file
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 71c6da84 upstream.

Currently context size (cra_ctxsize) doesn't specified for
ghash_async_alg. Which means it's zero. Thus crypto_create_tfm()
doesn't allocate needed space for ghash_async_ctx, so any
read/write to ctx (e.g. in ghash_async_init_tfm()) is not valid.
Signed-off-by: Andrey Ryabinin <aryabinin@odin.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit eb38f3a4 upstream.

We've got bug reports showing the old systemd-logind (at least
system-210) aborting unexpectedly, and this turned out to be because
of an invalid error code from close() call to evdev devices.  close()
is supposed to return only either EINTR or EBADFD, while the device
returned ENODEV.  logind was overreacting to it and decided to kill
itself when an unexpected error code was received.  What a tragedy.

The bad error code comes from flush fops, and actually evdev_flush()
returns ENODEV when device is disconnected or client's access to it is
revoked. But in these cases the fact that flush did not actually happen is
not an error, but rather normal behavior. For non-disconnected devices
result of flush is also not that interesting as there is no potential of
data loss and even if it fails application has no way of handling the
error. Because of that we are better off always returning success from
evdev_flush().

Also returning EINTR from flush()/close() is discouraged (as it is not
clear how application should handle this error), so let's stop taking
evdev->mutex interruptibly.

Bugzilla: http://bugzilla.suse.com/show_bug.cgi?id=939834Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[bwh: Backported to 3.2: there's no revoked flag to test]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit b632ffa7 upstream.

We have many WR opcodes that are only supported in kernel space
and/or require optional information to be copied into the WR
structure.  Reject all those not explicitly handled so that we
can't pass invalid information to drivers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 09bfda10 upstream.

With the radeon driver loaded the HP Compaq dc5750
Small Form Factor machine fails to resume from suspend.
Adding a quirk similar to other devices avoids
the problem and the system resumes properly.
Signed-off-by: Jeffery Miller <jmiller@neverware.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 51bc1404 upstream.

There have been many hard to track down bugs whereby userspace forgot to
flag a write buffer and then cause graphics corruption or a hung GPU
when that buffer was later purged under memory pressure (as the buffer
appeared clean, its pages would have been evicted rather than preserved
and any changes more recent than in the backing storage would be lost).
In retrospect this is a rare optimisation against memory pressure,
already the slow path. If we always mark the buffer as dirty when
accessed by the GPU, anything not used can still be evicted cheaply
(ideal behaviour for mark-and-sweep eviction) but we do not run the risk
of corruption. For correct read serialisation, userspace still has to
notify when the GPU writes to an object. However, there are certain
situations under which userspace may wish to tell white lies to the
kernel...
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Kristian Høgsberg <krh@bitplanet.net>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: "Goel, Akash" <akash.goel@intel.co>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 02bc933e upstream.

On Intel Baytrail, there is case when interrupt handler get called, no SPI
message is captured. The RX FIFO is indeed empty when RX timeout pending
interrupt (SSSR_TINT) happens.

Use the BIOS version where both HSUART and SPI are on the same IRQ. Both
drivers are using IRQF_SHARED when calling the request_irq function. When
running two separate and independent SPI and HSUART application that
generate data traffic on both components, user will see messages like
below on the console:

  pxa2xx-spi pxa2xx-spi.0: bad message state in interrupt handler

This commit will fix this by first checking Receiver Time-out Interrupt,
if it is disabled, ignore the request and return without servicing.
Signed-off-by: Tan, Jui Nee <jui.nee.tan@intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 35d4a0b6 upstream.

Fixes: 2a72f212 ("IB/uverbs: Remove dev_table")

Before this commit there was a device look-up table that was protected
by a spin_lock used by ib_uverbs_open and by ib_uverbs_remove_one. When
it was dropped and container_of was used instead, it enabled the race
with remove_one as dev might be freed just after:
dev = container_of(inode->i_cdev, struct ib_uverbs_device, cdev) but
before the kref_get.

In addition, this buggy patch added some dead code as
container_of(x,y,z) can never be NULL and so dev can never be NULL.
As a result the comment above ib_uverbs_open saying "the open method
will either immediately run -ENXIO" is wrong as it can never happen.

The solution follows Jason Gunthorpe suggestion from below URL:
https://www.mail-archive.com/linux-rdma@vger.kernel.org/msg25692.html

cdev will hold a kref on the parent (the containing structure,
ib_uverbs_device) and only when that kref is released it is
guaranteed that open will never be called again.

In addition, fixes the active count scheme to use an atomic
not a kref to prevent WARN_ON as pointed by above comment
from Jason.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 5e99b139 upstream.

The mlx4 IB driver implementation for ib_query_ah used a wrong offset
(28 instead of 29) when link type is Ethernet. Fixed to use the correct one.

Fixes: fa417f7b ('IB/mlx4: Add support for IBoE')
Signed-off-by: Shani Michaeli <shanim@mellanox.com>
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 0c78789e upstream.

In case the reconnection attempt fails.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
[bwh: Backported to 3.2: add local variable xprt]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit d6f1c17e upstream.

The lkey table is allocated with with a get_user_pages() with an
order based on a number of index bits from a module parameter.

The underlying kernel code cannot allocate that many contiguous pages.

There is no reason the underlying memory needs to be physically
contiguous.

This patch:
- switches the allocation/deallocation to vmalloc/vfree
- caps the number of bits to 23 to insure at least 1 generation bit
  o this matches the module parameter description
Reviewed-by: Vinit Agnihotri <vinit.abhay.agnihotri@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.2:
 - Adjust context
 - Add definition of qib_dev_warn(), added upstream by commit ddb88765
   ("IB/qib: Convert opcode counters to per-context")]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit c9eb256e upstream.

There is an issue with xfs's error reporting in some cases of I/O partially
failing and partially succeeding. Calls like fsync() can report success even
though not all I/O was successful in partial-failure cases such as one disk of
a RAID0 array being offline.

The issue can occur when there are more than one bio per xfs_ioend struct.
Each call to xfs_end_bio() for a bio completing will write a value to
ioend->io_error.  If a successful bio completes after any failed bio, no
error is reported do to it writing 0 over the error code set by any failed bio.
The I/O error information is now lost and when the ioend is completed
only success is reported back up the filesystem stack.

xfs_end_bio() should only set ioend->io_error in the case of BIO_UPTODATE
being clear.  ioend->io_error is initialized to 0 at allocation so only needs
to be updated by a failed bio. Also check that ioend->io_error is 0 so that
the first error reported will be the error code returned.
Signed-off-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 7f5dcaf1 upstream.

The unregister path of platform_device is broken. On registration, it
will register all resources with either a parent already set, or
type==IORESOURCE_{IO,MEM}. However, on unregister it will release
everything with type==IORESOURCE_{IO,MEM}, but ignore the others. There
are also cases where resources don't get registered in the first place,
like with devices created by of_platform_populate()*.

Fix the unregister path to be symmetrical with the register path by
checking the parent pointer instead of the type field to decide which
resources to unregister. This is safe because the upshot of the
registration path algorithm is that registered resources have a parent
pointer, and non-registered resources do not.

* It can be argued that of_platform_populate() should be registering
  it's resources, and they argument has some merit. However, there are
  quite a few platforms that end up broken if we try to do that due to
  overlapping resources in the device tree. Until that is fixed, we need
  to solve the immediate problem.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 3a496b00 upstream.

If the internal call to of_address_to_resource() fails, we end up
looping forever in of_find_matching_node_by_address().  This can be
caused by a defective device tree, or calling with an incorrect
matches argument.

Fix by calling of_find_matching_node() unconditionally at the end of
the loop.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 1642d09f upstream.

The v2 of NetGear WNA1000M uses a different idProduct: USB ID 0846:9043
Signed-off-by: Adrien Schildknecht <adrien+dev@schischi.me>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 9374e7d2 upstream.

Add new ID for ASUS N10 WiFi dongle.
Signed-off-by: Marek Vasut <marex@denx.de>
Tested-by: Marek Vasut <marex@denx.de>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: John W. Linville <linville@tuxdriver.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 924f92bf upstream.

Most of the time this isn't an issue since hotplugging an adaptor will
trigger a crtc mode change which in turn, causes the driver to probe
every DisplayPort for a dpcd. However, in cases where hotplugging
doesn't cause a mode change (specifically when one unplugs a monitor
from a DisplayPort connector, then plugs that same monitor back in
seconds later on the same port without any other monitors connected), we
never probe for the dpcd before starting the initial link training. What
happens from there looks like this:

	- GPU has only one monitor connected. It's connected via
	  DisplayPort, and does not go through an adaptor of any sort.

	- User unplugs DisplayPort connector from GPU.

	- Change in HPD is detected by the driver, we probe every
	  DisplayPort for a possible connection.

	- Probe the port the user originally had the monitor connected
	  on for it's dpcd. This fails, and we clear the first (and only
	  the first) byte of the dpcd to indicate we no longer have a
	  dpcd for this port.

	- User plugs the previously disconnected monitor back into the
	  same DisplayPort.

	- radeon_connector_hotplug() is called before everyone else,
	  and tries to handle the link training. Since only the first
	  byte of the dpcd is zeroed, the driver is able to complete
	  link training but does so against the wrong dpcd, causing it
	  to initialize the link with the wrong settings.

	- Display stays blank (usually), dpcd is probed after the
	  initial link training, and the driver prints no obvious
	  messages to the log.

In theory, since only one byte of the dpcd is chopped off (specifically,
the byte that contains the revision information for DisplayPort), it's
not entirely impossible that this bug may not show on certain monitors.
For instance, the only reason this bug was visible on my ASUS PB238
monitor was due to the fact that this monitor using the enhanced framing
symbol sequence, the flag for which is ignored if the radeon driver
thinks that the DisplayPort version is below 1.1.
Signed-off-by: Stephen Chandler Paul <cpaul@redhat.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit ffeecc52 upstream.

struct xfs_attr_leafblock contains 'entries' array which is declared
with size 1 altough it can in fact contain much more entries. Since this
array is followed by further struct members, gcc (at least in version
4.8.3) thinks that the array has the fixed size of 1 element and thus
may optimize away all accesses beyond the end of array resulting in
non-working code. This problem was only observed with userspace code in
xfsprogs, however it's better to be safe in kernel as well and have
matching kernel and xfsprogs definitions.
Signed-off-by: Jan Kara <jack@suse.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 5556e7e6 upstream.

Consider eCryptfs dcache entries to be stale when the corresponding
lower inode's i_nlink count is zero. This solves a problem caused by the
lower inode being directly modified, without going through the eCryptfs
mount, leaving stale eCryptfs dentries cached and the eCryptfs inode's
i_nlink count not being cleared.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Richard Weinberger <richard@nod.at>
[bwh: Backported to 3.2:
 - Test d_revalidate pointer directly rather than a DCACHE_OP flag
 - Open-code d_inode()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>