Currently writing the attributes with "echo" will result in comparing:
"enabled\n" with "enabled\0" and attribute is always set to false.

Use the sysfs_streq() instead because it treats both NUL and
new-line-then-NUL as equivalent string terminations.
Signed-off-by: Dan Bogdan Nechita <dan.bogdan.nechita@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix RDAC read back errors caused by a typo. Value must shift by 2.

Fixes: a4bd3949 ("drivers/misc/ad525x_dpot.c: new features")
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add device ids for Broxton SoC based devices.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'lkdtm-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-testing

Kees writes:

Become maintainer, add hardening tests for use-after-free and atomic wrapping.

Merge tag 'extcon-next-for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/extcon into char-misc-testing

Chanwoo writes:

Update extcon for 4.6

Detailed description for patchset:
1. Add new EXTCON_CHG_USB_SDP type
- SDP (Standard Downstream Port) USB Charging Port
  means the charging connector.a

2. Add the VBUS detection by using GPIO on extcon-palmas
- Beaglex15 board uses the extcon-palmas driver
  But, beaglex15 board need the GPIO support for VBUS
  detection.

3. Fix the minor issue of extcon drivers

We want the fixes in here, and others are sending us pull requests based
on this kernel tree.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This improves the order of operations on the use-after-free tests to
try to make sure we've executed any available sanity-checking code,
and to report the poisoning that was found.
Signed-off-by: Kees Cook <keescook@chromium.org>

dmesg output of running this LKDTM test with PaX:

[187095.475573] lkdtm: No crash points registered, enable through debugfs
[187118.020257] lkdtm: Performing direct entry WRAP_ATOMIC
[187118.030045] lkdtm: attempting atomic underflow
[187118.030929] PAX: refcount overflow detected in: bash:1790, uid/euid: 0/0
[187118.071667] PAX: refcount overflow occured at: lkdtm_do_action+0x19e/0x400 [lkdtm]
[187118.081423] CPU: 3 PID: 1790 Comm: bash Not tainted 4.2.6-pax-refcount-split+ #2
[187118.083403] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[187118.102596] task: ffff8800da8de040 ti: ffff8800da8e4000 task.ti: ffff8800da8e4000
[187118.111321] RIP: 0010:[<ffffffffc00fc2fe>]  [<ffffffffc00fc2fe>] lkdtm_do_action+0x19e/0x400 [lkdtm]
...
[187118.128074] lkdtm: attempting atomic overflow
[187118.128080] PAX: refcount overflow detected in: bash:1790, uid/euid: 0/0
[187118.128082] PAX: refcount overflow occured at: lkdtm_do_action+0x1b6/0x400 [lkdtm]
[187118.128085] CPU: 3 PID: 1790 Comm: bash Not tainted 4.2.6-pax-refcount-split+ #2
[187118.128086] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[187118.128088] task: ffff8800da8de040 ti: ffff8800da8e4000 task.ti: ffff8800da8e4000
[187118.128092] RIP: 0010:[<ffffffffc00fc316>]  [<ffffffffc00fc316>] lkdtm_do_action+0x1b6/0x400 [lkdtm]
Signed-off-by: David Windsor <dave@progbits.org>
[cleaned up whitespacing, keescook]
Signed-off-by: Kees Cook <keescook@chromium.org>

The current tests for read/write after free work on slab
allocated memory. Memory straight from the buddy allocator
may behave slightly differently and have a different set
of parameters to test. Add tests for those cases as well.

On a basic x86 boot:

 # echo WRITE_BUDDY_AFTER_FREE > /sys/kernel/debug/provoke-crash/DIRECT
[   22.291950] lkdtm: Performing direct entry WRITE_BUDDY_AFTER_FREE
[   22.292983] lkdtm: Writing to the buddy page before free
[   22.293950] lkdtm: Attempting bad write to the buddy page after free

 # echo READ_BUDDY_AFTER_FREE > /sys/kernel/debug/provoke-crash/DIRECT
[   32.375601] lkdtm: Performing direct entry READ_BUDDY_AFTER_FREE
[   32.379896] lkdtm: Value in memory before free: 12345678
[   32.383854] lkdtm: Attempting to read from freed memory
[   32.389309] lkdtm: Buddy page was not poisoned

On x86 with CONFIG_DEBUG_PAGEALLOC and debug_pagealloc=on:

 # echo WRITE_BUDDY_AFTER_FREE > /sys/kernel/debug/provoke-crash/DIRECT
[   17.475533] lkdtm: Performing direct entry WRITE_BUDDY_AFTER_FREE
[   17.477360] lkdtm: Writing to the buddy page before free
[   17.479089] lkdtm: Attempting bad write to the buddy page after free
[   17.480904] BUG: unable to handle kernel paging request at
ffff88000ebd8000

 # echo READ_BUDDY_AFTER_FREE > /sys/kernel/debug/provoke-crash/DIRECT
[   14.606433] lkdtm: Performing direct entry READ_BUDDY_AFTER_FREE
[   14.607447] lkdtm: Value in memory before free: 12345678
[   14.608161] lkdtm: Attempting to read from freed memory
[   14.608860] BUG: unable to handle kernel paging request at
ffff88000eba3000

Note that arches without ARCH_SUPPORTS_DEBUG_PAGEALLOC may not
produce the same crash.
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

The SLUB allocator may use the first word of a freed block to store the
freelist information. This may make it harder to test poisoning
features. Change the WRITE_AFTER_FREE test to better match what
the READ_AFTER_FREE test does and also print out a big more information.
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

In a similar manner to WRITE_AFTER_FREE, add a READ_AFTER_FREE
test to test free poisoning features. Sample output when
no sanitization is present:

 # echo READ_AFTER_FREE > /sys/kernel/debug/provoke-crash/DIRECT
[   17.542473] lkdtm: Performing direct entry READ_AFTER_FREE
[   17.543866] lkdtm: Value in memory before free: 12345678
[   17.545212] lkdtm: Attempting bad read from freed memory
[   17.546542] lkdtm: Memory was not poisoned

with slub_debug=P:

 # echo READ_AFTER_FREE > /sys/kernel/debug/provoke-crash/DIRECT
[   22.415531] lkdtm: Performing direct entry READ_AFTER_FREE
[   22.416366] lkdtm: Value in memory before free: 12345678
[   22.417137] lkdtm: Attempting bad read from freed memory
[   22.417897] lkdtm: Memory correctly poisoned, calling BUG
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

Officially claim maintainership over the LKDTM code.
Signed-off-by: Kees Cook <keescook@chromium.org>

Pull sparc fixes from David Miller:

 1) System call tracing doesn't handle register contents properly across
    the trace.  From Mike Frysinger.

 2) Hook up copy_file_range

 3) Build fix for 32-bit with newer tools.

 4) New sun4v watchdog driver, from Wim Coekaerts.

 5) Set context system call has to allow for servicable faults when we
    flush the register windows to memory

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Fix sparc64_set_context stack handling.
  sparc32: Add -Wa,-Av8 to KBUILD_CFLAGS.
  Add sun4v_wdt watchdog driver
  sparc: Fix system call tracing register handling.
  sparc: Hook up copy_file_range syscall.

Like a signal return, we should use synchronize_user_stack() rather
than flush_user_windows().
Reported-by: Ilya Malakhov <ilmalakhovthefirst@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Binutils used to be (erroneously) extremely permissive about
instruction usage.  But that got fixed and if you don't properly tell
it to accept classes of instructions it will fail.

This uncovered a specs bug on sparc in gcc where it wouldn't pass the
proper options to binutils options.

Deal with this in the kernel build by adding -Wa,-Av8 to KBUILD_CFLAGS.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Palams extcon IRQs are nested threaded and wired to the Palmas
inerrupt controller. So, this flag is not required for nested irqs
anymore, since commit 3c646f2c ("genirq: Don't suspend
nested_thread irqs over system suspend") was merged.

Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Roger Quadros <rogerq@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

Pull perf fixes from Thomas Gleixner:
 "A rather largish series of 12 patches addressing a maze of race
  conditions in the perf core code from Peter Zijlstra"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Robustify task_function_call()
  perf: Fix scaling vs. perf_install_in_context()
  perf: Fix scaling vs. perf_event_enable()
  perf: Fix scaling vs. perf_event_enable_on_exec()
  perf: Fix ctx time tracking by introducing EVENT_TIME
  perf: Cure event->pending_disable race
  perf: Fix race between event install and jump_labels
  perf: Fix cloning
  perf: Only update context time when active
  perf: Allow perf_release() with !event->ctx
  perf: Do not double free
  perf: Close install vs. exit race

Pull x86 fixes from Thomas Gleixner:
 "This update contains:

   - Hopefully the last ASM CLAC fixups

   - A fix for the Quark family related to the IMR lock which makes
     kexec work again

   - A off-by-one fix in the MPX code.  Ironic, isn't it?

   - A fix for X86_PAE which addresses once more an unsigned long vs
     phys_addr_t hickup"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mpx: Fix off-by-one comparison with nr_registers
  x86/mm: Fix slow_virt_to_phys() for X86_PAE again
  x86/entry/compat: Add missing CLAC to entry_INT80_32
  x86/entry/32: Add an ASM_CLAC to entry_SYSENTER_32
  x86/platform/intel/quark: Change the kernel's IMR lock bit to false

Pull scheduler fixlet from Thomas Gleixner:
 "A trivial printk typo fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/deadline: Fix trivial typo in printk() message

Pull irq fixes from Thomas Gleixner:
 "Four small fixes for irqchip drivers:

   - Add missing low level irq handler initialization on mxs, so
     interrupts can acutally be delivered

   - Add a missing barrier to the GIC driver

   - Two fixes for the GIC-V3-ITS driver, addressing a double EOI write
     and a cache flush beyond the actual region"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3: Add missing barrier to 32bit version of gic_read_iar()
  irqchip/mxs: Add missing set_handle_irq()
  irqchip/gicv3-its: Avoid cache flush beyond ITS_BASERn memory size
  irqchip/gic-v3-its: Fix double ICC_EOIR write for LPI in EOImode==1

Pull staging/android fix from Greg KH:
 "Here is one patch, for the android binder driver, to resolve a
  reported problem.  Turns out it has been around for a while (since
  3.15), so it is good to finally get it resolved.

  It has been in linux-next for a while with no reported issues"

* tag 'staging-4.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  drivers: android: correct the size of struct binder_uintptr_t for BC_DEAD_BINDER_DONE

Pull USB fixes from Greg KH:
 "Here are a few USB fixes for 4.5-rc6

  They fix a reported bug for some USB 3 devices by reverting the recent
  patch, a MAINTAINERS change for some drivers, some new device ids, and
  of course, the usual bunch of USB gadget driver fixes.

  All have been in linux-next for a while with no reported issues"

* tag 'usb-4.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  MAINTAINERS: drop OMAP USB and MUSB maintainership
  usb: musb: fix DMA for host mode
  usb: phy: msm: Trigger USB state detection work in DRD mode
  usb: gadget: net2280: fix endpoint max packet for super speed connections
  usb: gadget: gadgetfs: unregister gadget only if it got successfully registered
  usb: gadget: remove driver from pending list on probe error
  Revert "usb: hub: do not clear BOS field during reset device"
  usb: chipidea: fix return value check in ci_hdrc_pci_probe()
  usb: chipidea: error on overflow for port_test_write
  USB: option: add "4G LTE usb-modem U901"
  USB: cp210x: add IDs for GE B650V3 and B850V3 boards
  USB: option: add support for SIM7100E
  usb: musb: Fix DMA desired mode for Mentor DMA engine
  usb: gadget: fsl_qe_udc: fix IS_ERR_VALUE usage
  usb: dwc2: USB_DWC2 should depend on HAS_DMA
  usb: dwc2: host: fix the data toggle error in full speed descriptor dma
  usb: dwc2: host: fix logical omissions in dwc2_process_non_isoc_desc
  usb: dwc3: Fix assignment of EP transfer resources
  usb: dwc2: Add extra delay when forcing dr_mode

Pull vfs fixes from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  do_last(): ELOOP failure exit should be done after leaving RCU mode
  should_follow_link(): validate ->d_seq after having decided to follow
  namei: ->d_inode of a pinned dentry is stable only for positives
  do_last(): don't let a bogus return value from ->open() et.al. to confuse us
  fs: return -EOPNOTSUPP if clone is not supported
  hpfs: don't truncate the file when delete fails

Pull ARM SoC fixes from Olof Johansson:
 "We didn't have a batch last week, so this one is slightly larger.

  None of them are scary though, a handful of fixes for small DT pieces,
  replacing properties with newer conventions.

  Highlights:
   - N900 fix for setting system revision
   - onenand init fix to avoid filesystem corruption
   - Clock fix for audio on Beaglebone-x15
   - Fixes on shmobile to deal with CONFIG_DEBUG_RODATA (default y in 4.6)

  + misc smaller stuff"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  MAINTAINERS: Extend info, add wiki and ml for meson arch
  MAINTAINERS: alpine: add a new maintainer and update the entry
  ARM: at91/dt: fix typo in sama5d2 pinmux descriptions
  ARM: OMAP2+: Fix onenand initialization to avoid filesystem corruption
  Revert "regulator: tps65217: remove tps65217.dtsi file"
  ARM: shmobile: Remove shmobile_boot_arg
  ARM: shmobile: Move shmobile_smp_{mpidr, fn, arg}[] from .text to .bss
  ARM: shmobile: r8a7779: Remove remainings of removed SCU boot setup code
  ARM: shmobile: Move shmobile_scu_base from .text to .bss
  ARM: OMAP2+: Fix omap_device for module reload on PM runtime forbid
  ARM: OMAP2+: Improve omap_device error for driver writers
  ARM: DTS: am57xx-beagle-x15: Select SYS_CLK2 for audio clocks
  ARM: dts: am335x/am57xx: replace gpio-key,wakeup with wakeup-source property
  ARM: OMAP2+: Set system_rev from ATAGS for n900
  ARM: dts: orion5x: fix the missing mtd flash on linkstation lswtgl
  ARM: dts: kirkwood: use unique machine name for ds112
  ARM: dts: imx6: remove bogus interrupt-parent from CAAM node

... or we risk seeing a bogus value of d_is_symlink() there.

Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... otherwise d_is_symlink() above might have nothing to do with
the inode value we've got.

Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

both do_last() and walk_component() risk picking a NULL inode out
of dentry about to become positive, *then* checking its flags and
seeing that it's not negative anymore and using (already stale by
then) value they'd fetched earlier.  Usually ends up oopsing soon
after that...

Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... into returning a positive to path_openat(), which would interpret that
as "symlink had been encountered" and proceed to corrupt memory, etc.
It can only happen due to a bug in some ->open() instance or in some LSM
hook, etc., so we report any such event *and* make sure it doesn't trick
us into further unpleasantness.

Cc: stable@vger.kernel.org # v3.6+, at least
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

-EBADF is a rather confusing error if an operations is not supported,
and nfsd gets rather upset about it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The delete opration can allocate additional space on the HPFS filesystem
due to btree split. The HPFS driver checks in advance if there is
available space, so that it won't corrupt the btree if we run out of space
during splitting.

If there is not enough available space, the HPFS driver attempted to
truncate the file, but this results in a deadlock since the commit
7dd29d8d ("HPFS: Introduce a global mutex
and lock it on every callback from VFS").

This patch removes the code that tries to truncate the file and -ENOSPC is
returned instead. If the user hits -ENOSPC on delete, he should try to
delete other files (that are stored in a leaf btree node), so that the
delete operation will make some space for deleting the file stored in
non-leaf btree node.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: stable@vger.kernel.org	# 2.6.39+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Merge fixes from Andrew Morton:
 "10 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  dax: move writeback calls into the filesystems
  dax: give DAX clearing code correct bdev
  ext4: online defrag not supported with DAX
  ext2, ext4: only set S_DAX for regular inodes
  block: disable block device DAX by default
  ocfs2: unlock inode if deleting inode from orphan fails
  mm: ASLR: use get_random_long()
  drivers: char: random: add get_random_long()
  mm: numa: quickly fail allocations for NUMA balancing on full nodes
  mm: thp: fix SMP race condition between THP page fault and MADV_DONTNEED

Pull ext2/4 DAX fix from Ted Ts'o:
 "This fixes a file system corruption bug with DAX"

* tag 'tags/ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext2, ext4: fix issue with missing journal entry in ext4_dax_mkwrite()

Pull PCI fixes from Bjorn Helgaas:
 "Enumeration:
    Revert x86 pcibios_alloc_irq() to fix regression (Bjorn Helgaas)

  Marvell MVEBU host bridge driver:
    Restrict build to 32-bit ARM (Thierry Reding)"

* tag 'pci-v4.5-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: mvebu: Restrict build to 32-bit ARM
  Revert "PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()"
  Revert "PCI: Add helpers to manage pci_dev->irq and pci_dev->irq_managed"
  Revert "x86/PCI: Don't alloc pcibios-irq when MSI is enabled"

As it is currently written ext4_dax_mkwrite() assumes that the call into
__dax_mkwrite() will not have to do a block allocation so it doesn't create
a journal entry.  For a read that creates a zero page to cover a hole
followed by a write that actually allocates storage this is incorrect.  The
ext4_dax_mkwrite() -> __dax_mkwrite() -> __dax_fault() path calls
get_blocks() to allocate storage.

Fix this by having the ->page_mkwrite fault handler call ext4_dax_fault()
as this function already has all the logic needed to allocate a journal
entry and call __dax_fault().

Also update the ext2 fault handlers in this same way to remove duplicate
code and keep the logic between ext2 and ext4 the same.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Pull clk fix from Stephen Boyd:
 "One small fix to keep OMAP platforms working across a suspend/resume
  cycle"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: ti: omap3+: dpll: use non-locking version of clk_get_rate

Previously calls to dax_writeback_mapping_range() for all DAX filesystems
(ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range().

dax_writeback_mapping_range() needs a struct block_device, and it used
to get that from inode->i_sb->s_bdev.  This is correct for normal inodes
mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
block devices and for XFS real-time files.

Instead, call dax_writeback_mapping_range() directly from the filesystem
->writepages function so that it can supply us with a valid block
device.  This also fixes DAX code to properly flush caches in response
to sync(2).
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dax_clear_blocks() needs a valid struct block_device and previously it
was using inode->i_sb->s_bdev in all cases.  This is correct for normal
inodes on mounted ext2, ext4 and XFS filesystems, but is incorrect for
DAX raw block devices and for XFS real-time devices.

Instead, rename dax_clear_blocks() to dax_clear_sectors(), and change
its arguments to take a bdev and a sector instead of an inode and a
block.  This better reflects what the function does, and it allows the
filesystem and raw block device code to pass in an appropriate struct
block_device.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Online defrag operations for ext4 are hard coded to use the page cache.
See ext4_ioctl() -> ext4_move_extents() -> move_extent_per_page()

When combined with DAX I/O, which circumvents the page cache, this can
result in data corruption.  This was observed with xfstests ext4/307 and
ext4/308.

Fix this by only allowing online defrag for non-DAX files.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When S_DAX is set on an inode we assume that if there are pages attached
to the mapping (mapping->nrpages != 0), those pages are clean zero pages
that were used to service reads from holes.  Any dirty data associated
with the inode should be in the form of DAX exceptional entries
(mapping->nrexceptional) that is written back via
dax_writeback_mapping_range().

With the current code, though, this isn't always true.  For example,
ext2 and ext4 directory inodes can have S_DAX set, but have their dirty
data stored as dirty page cache entries.  For these types of inodes,
having S_DAX set doesn't really make sense since their I/O doesn't
actually happen through the DAX code path.

Instead, only allow S_DAX to be set for regular inodes for ext2 and
ext4.  This allows us to have strict DAX vs non-DAX paths in the
writeback code.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>