Overlayfs should be mounted read-only when upper-fs is read-only or nonexistent.
But now it can be remounted read-write and this can cause kernel panic.
So we should prevent read-write remount when the above situation happens.
Signed-off-by: Seunghun Lee <waydi1@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Current multi-layer support overlayfs has a regression in
.lookup(). If there is a directory in upperdir and a regular
file has same name in lowerdir in a merged directory, lower
file is hidden and upper directory is set to opaque in former
case. But it is changed in present code.

In lowerdir lookup path, if a found inode is not directory,
the type checking of previous inode is missing. This inode
will be copied to the lowerstack of ovl_entry directly.

That will lead to several wrong conditions, for example,
the reading of the directory in upperdir may return an error
like:

   ls: reading directory .: Not a directory

This patch makes the lowerdir lookup path check the opaque
for non-directory file too.
Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

The function ovl_fill_super() in recently multi-layer support
version will incorrectly return 0 at error handling path and
then cause kernel panic.

This failure can be reproduced by mounting a overlayfs with
upperdir and workdir in different mounts.

And also, If the memory allocation of *lower_mnt* fail, this
function may return an zero either.

This patch fix this problem by setting *err* to proper error
number before jumping to error handling path.
Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

This patch adds two macros:

OVL_XATTR_PRE_NAME and OVL_XATTR_PRE_LEN

to present ovl_xattr name prefix and its length. Also, a
new macro OVL_XATTR_OPAQUE is introduced to replace old
*ovl_opaque_xattr*.

Fix the length of "trusted.overlay." to *16*.
Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

This patch removes redundant blanks lines in overlayfs.
Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Allow "lowerdir=" option to contain multiple lower directories separated by
a colon (e.g. "lowerdir=/bin:/usr/bin").  Colon characters in filenames can
be escaped with a backslash.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Make "upperdir=" mount option optional.  If "upperdir=" is not given, then
the "workdir=" option is also optional (and ignored if given).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Move common checks into ovl_mount_dir() helper.

Create helper for looking up lower directories.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Move allocation of root entry above to where it's needed.

Move initializations related to upperdir and workdir near each other.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Handle "no upper layer" case in statfs.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

"Suppose you have in one of the lower layers a filesystem with
->lookup()-enforced upper limit on name length.  Pretty much every local fs
has one, but... they are not all equal.  255 characters is the common upper
limit, but e.g. jffs2 stops at 254, minixfs upper limit is somewhere from
14 to 60, depending upon version, etc.  You are doing a lookup for
something that is present in upper layer, but happens to be too long for
one of the lower layers.  Too bad - ENAMETOOLONG for you..."
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Not checking whiteouts on lowest layer was an optimization (there's nothing
to white out there), but it could result in inconsitent behavior when a
layer previously used as upper/middle is later used as lowest. 
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Look up dentry in all relevant layers.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

If multiple lower layers exist, merge them as well in readdir according to
the same rules as merging upper with lower.  I.e. take whiteouts and opaque
directories into account on all but the lowers layer.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Add helper to iterate through all the layers, starting from the upper layer
(if exists) and continuing down through the lower layers.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Add multiple lower layers to 'struct ovl_fs' and 'struct ovl_entry'.

ovl_entry will have an array of paths, instead of just the dentry.  This
allows a compact array containing just the layers which exist at current
point in the tree (which is expected to be a small number for the majority
of dentries).

The number of layers is not limited by this infrastructure.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

When removing an empty opaque directory, then it makes no sense to replace
it with an exact replica of itself before removal.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

OVL_PATH_PURE_UPPER -> __OVL_PATH_UPPER | __OVL_PATH_PURE
OVL_PATH_UPPER      -> __OVL_PATH_UPPER
OVL_PATH_MERGE      -> __OVL_PATH_UPPER | __OVL_PATH_MERGE
OVL_PATH_LOWER      -> 0

Multiple R/O layers will allow __OVL_PATH_MERGE without __OVL_PATH_UPPER.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Don't make a separate pass for checking whiteouts, since we can do it while
reading the upper directory.

This will make it easier to handle multiple layers.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Pull libata fixes from Tejun Heo:
 "Three libata fixes for v3.18.  Nothing too interesting.  PCI ID ID and
  quirk additions to ahci and an error handling path fix in sata_fsl"

* 'for-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  ahci: disable MSI on SAMSUNG 0xa800 SSD
  sata_fsl: fix error handling of irq_of_parse_and_map
  AHCI: Add DeviceIDs for Sunrise Point-LP SATA controller

Pull watchdog fix from Wim Van Sebroeck:
 "Fix the watchdog mask bit offset for Exynos7"

* git://www.linux-watchdog.org/linux-watchdog:
  watchdog: s3c2410_wdt: Fix the mask bit offset for Exynos7

Pull i2c fixes from Wolfram Sang:
 "Here are two more driver bugfixes for I2C which would be good to have"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: cadence: Set the hardware time-out register to maximum value
  i2c: davinci: generate STP always when NACK is received

The watchdog mask bit offset listed for Exynos7 is incorrect.
Fix this.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Acked-by: Naveen Krishna Chatradhi <naveenkrishna.ch@gmail.com
Reviewd-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Pull x86 fixes from Thomas Gleixner:
 "Two final fixlets for 3.18:
   - Prevent microcode reload wreckage on 32bit
   - Unbreak cross compilation"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, microcode: Limit the microcode reloading to 64-bit for now
  x86: Use $(OBJDUMP) instead of plain objdump

Pull sound fixlet from Takashi Iwai:
 "Just one commit for adding a copule of HD-audio quirk entries"

* tag 'sound-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda/realtek - Add headset Mic support for new Dell machine

Pull drm intel fixes from Dave Airlie:
 "Two intel stable fixes, that should be it from me for this round"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: Unlock panel even when LVDS is disabled
  drm/i915: More cautious with pch fifo underruns

Pull ACPI backlight fix from Rafael Wysocki:
 "This is a simple fix for an ACPI backlight regression introduced by a
  recent commit that overlooked a corner case which should have been
  taken into account"

* tag 'pm+acpi-3.18-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: update condition to check if device is in _DOD list

Silence some pch fifo underrun reports and panel locking backtraces,
both cc: stable.

* tag 'drm-intel-fixes-2014-12-04' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Unlock panel even when LVDS is disabled
  drm/i915: More cautious with pch fifo underruns

Pull media fixes from Mauro Carvalho Chehab:
 "A core fix and some driver fixes:
   - regression fix in Remote Controller core affecting RC6 protocol
     handling
   - fix video buffer handling in cx23885
   - race fix in solo6x10
   - fix image selection in smiapp
   - fix reported payload size on s2255drv
   - two updates for MAINTAINERS file"

* tag 'media/v3.18-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  [media] rc-core: fix toggle handling in the rc6 decoder
  MAINTAINERS: Update mchehab's addresses
  [media] cx23885: use sg = sg_next(sg) instead of sg++
  [media] s2255drv: fix payload size for JPG, MJPEG
  [media] Update MAINTAINERS for solo6x10
  [media] solo6x10: fix a race in IRQ handler
  [media] smiapp: Only some selection targets are settable

A typo "header=y" was introduced by commit 7071cf7f ("uapi: add
missing network related headers to kbuild").
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Cadence I2C controller has bug wherein it generates invalid read transactions
after timeout in master receiver mode. This driver does not use the HW
timeout and this interrupt is disabled but the feature itself cannot be
disabled. Hence, this patch writes the maximum value (0xFF) to this register.
This is one of the workarounds to this bug and it will not avoid the issue
completely but reduces the chances of error.
Signed-off-by: Vishnu Motghare <vishnum@xilinx.com>
Signed-off-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

According to I2C specification the NACK should be handled as follows:
"When SDA remains HIGH during this ninth clock pulse, this is defined as the Not
Acknowledge signal. The master can then generate either a STOP condition to
abort the transfer, or a repeated START condition to start a new transfer."
[I2C spec Rev. 6, 3.1.6: http://www.nxp.com/documents/user_manual/UM10204.pdf]

Currently the Davinci i2c driver interrupts the transfer on receipt of a
NACK but fails to send a STOP in some situations and so makes the bus
stuck until next I2C IP reset (idle/enable).

For example, the issue will happen during SMBus read transfer which
consists from two i2c messages write command/address and read data:

S Slave Address Wr A Command Code A Sr Slave Address Rd A D1..Dn A P
<--- write -----------------------> <--- read --------------------->

The I2C client device will send NACK if it can't recognize "Command Code"
and it's expected from I2C master to generate STP in this case.
But now, Davinci i2C driver will just exit with -EREMOTEIO and STP will
not be generated.

Hence, fix it by generating Stop condition (STP) always when NACK is received.

This patch fixes Davinci I2C in the same way it was done for OMAP I2C
commit cda2109a ("i2c: omap: query STP always when NACK is received").
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reported-by: Hein Tibosch <hein_tibosch@yahoo.es>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

Just like 0x1600 which got blacklisted by 66a7cbc3 ("ahci: disable
MSI instead of NCQ on Samsung pci-e SSDs on macbooks"), 0xa800 chokes
on NCQ commands if MSI is enabled.  Disable MSI.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Dominik Mierzejewski <dominik@greysector.net>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=89171
Cc: stable@vger.kernel.org

It appears that some SCHEDULE_USER (asm for schedule_user) callers
in arch/x86/kernel/entry_64.S are called from RCU kernel context,
and schedule_user will return in RCU user context.  This causes RCU
warnings and possible failures.

This is intended to be a minimal fix suitable for 3.18.
Reported-and-tested-by: Dave Jones <davej@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull i2c bugfixes from Wolfram Sang:
 "A few driver bugfixes for 3.18"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: omap: fix i207 errata handling
  i2c: designware: prevent early stop on TX FIFO empty
  i2c: omap: fix NACK and Arbitration Lost irq handling

Pull PCI fix from Bjorn Helgaas:
 "This fixes a Tegra20 regression that we introduced during the v3.18
  merge window"

* tag 'pci-v3.18-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: tegra: Use physical range for I/O mapping

Pull devicetree bugfix from Grant Likely:
 "One more bug fix for v3.18.  I debated whether or not to send you this
  merge request because we're at such a late rc.  The bug isn't critical
  in that there is only one system known to be affected and the patch is
  easy to backport.  The codepath is used by pretty much every DT based
  system, so there is risk a of regression (it /should/ be safe, but
  I've been bitten by stuff that should be safe before).  I've had it in
  linux-next for a week and haven't received any complaints.

  I think it probably should just be merged right away rather than
  waiting for the merge window and backporting.  It does fix a real bug
  and the code is theoretically safer after the change.  I can't think
  of any situation where it would be dangerous to reserve the DT memory
  an extra time.

  Summary from tag:

    Single bugfix for boot failure seen in the wild.  The memory reserve
    code tries to be clever about reserving the FDT, but it should just
    go ahead and reserve it unconditionally to avoid the problem of
    partial overlap described in the patch"

* tag 'devicetree-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/glikely/linux:
  of/fdt: memblock_reserve /memreserve/ regions in the case of partial overlap

Pull block core regression fix from Jens Axboe:
 "Single fix for a regression introduced in this development cycle,
  where dm on top of dif/dix is broken.  From Darrick Wong"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix regression where bio_integrity_process uses wrong bio_vec iterator