The main 'md' thread is needed for processing writes, so if it blocks
write requests could be delayed.

Starting a new thread requires some GFP_KERNEL allocations and so can
wait for writes to complete.  This can deadlock.

So instead, ask a workqueue to start the sync thread.
There is no particular rush for this to happen, so any work queue
will do.

MD_RECOVERY_RUNNING is used to ensure only one thread is started.
Reported-by: NBillStuff <billstuff2001@sbcglobal.net>
Signed-off-by: NNeilBrown <neilb@suse.de>

We don't really need the full mddev_lock here, and having to
drop it is messy.
RCU is enough to protect these lists.
Signed-off-by: NNeilBrown <neilb@suse.de>

printk may cause long time lapse if value of printk_delay in sysctl is
configured large by user. If register_md_personality takes long time to print in
spinlock pers_lock, we may encounter high CPU usage rate when there are other
pers_lock competitors who may be blocked to spin.
We can avoid this condition by moving printk out of coverage of pers_lock
spinlock.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

We don't really need that for_each loop, or those MD_BUGs.
Signed-off-by: NNeilBrown <neilb@suse.de>

Having both is a waste - just use the one.
Signed-off-by: NNeilBrown <neilb@suse.de>

md_super_wait is really just wait_event() open-coded.
So use the macro instead.
Signed-off-by: NNeilBrown <neilb@suse.de>

In general we don't allow an array to be stopped if it is in use.
However if the array hasn't really been started yet, then any
apparent use is an anomily, probably due to 'udev' or similar
having a look to see what is there.

This means that if something goes wrong while assembling an array
it cannot reliably be un-assembled - STOP_ARRAY could fail.
There is no value here, so change do_md_stop() to succeed
despite concurrent opens if the array has not yet been
activated.  i.e. if ->pers is NULL.
Reported-by: N"Baldysiak, Pawel" <pawel.baldysiak@intel.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

process_checks() always returns '0', so change it to 'void'.
Signed-off-by: NNeilBrown <neilb@suse.de>

raid5: fix init_stripe() inconsistencies

1) remove_hash() is not necessary. We will only be called right after
   get_free_stripe(). There we have already a call to remove_hash().

2) Tracing prints out the sector of the freed stripe and not the sector
   that we want to initialize.
Signed-off-by: NNeilBrown <neilb@suse.de>

Signed-off-by: NNeilBrown <neilb@suse.de>

Using {set,clear}_bit is more consistent than shifting and masking.

No functional change.
Signed-off-by: NNeilBrown <neilb@suse.de>

Signed-off-by: NNeilBrown <neilb@suse.de>

If two threads call bitmap_unplug at the same time, then
one might schedule all the writes, and the other might
decide that it doesn't need to wait.  But really it does.

It rarely hurts to wait when it isn't absolutely necessary,
and the current code doesn't really focus on 'absolutely necessary'
anyway.  So just wait always.

This can potentially lead to data corruption if a crash happens
at an awkward time and data was written before the bitmap was
updated.  It is very unlikely, but this should go to -stable
just to be safe.  Appropriate for any -stable.
Signed-off-by: NNeilBrown <neilb@suse.de>
Cc: stable@vger.kernel.org (please delay until 3.18 is released)

It has come to my attention (thanks Martin) that 'discard_zeroes_data'
is only a hint.  Some devices in some cases don't do what it
says on the label.

The use of DISCARD in RAID5 depends on reads from discarded regions
being predictably zero.  If a write to a previously discarded region
performs a read-modify-write cycle it assumes that the parity block
was consistent with the data blocks.  If all were zero, this would
be the case.  If some are and some aren't this would not be the case.
This could lead to data corruption after a device failure when
data needs to be reconstructed from the parity.

As we cannot trust 'discard_zeroes_data', ignore it by default
and so disallow DISCARD on all raid4/5/6 arrays.

As many devices are trustworthy, and as there are benefits to using
DISCARD, add a module parameter to over-ride this caution and cause
DISCARD to work if discard_zeroes_data is set.

If a site want to enable DISCARD on some arrays but not on others they
should select DISCARD support at the filesystem level, and set the
raid456 module parameter.
    raid456.devices_handle_discard_safely=Y

As this is a data-safety issue, I believe this patch is suitable for
-stable.
DISCARD support for RAID456 was added in 3.7

Cc: Shaohua Li <shli@kernel.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Heinz Mauelshagen <heinzm@redhat.com>
Cc: stable@vger.kernel.org (3.7+)
Acked-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: NMike Snitzer <snitzer@redhat.com>
Fixes: 620125f2Signed-off-by: NNeilBrown <neilb@suse.de>

Pull slave-dmaengine fixes from Vinod Koul:
 "Two small fixes for omap dmaengine driver which fixes cyclic suspend
  and resume"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: omap-dma: Restore the CLINK_CTRL in resume path
  dmaengine: omap-dma: Add memory barrier to dma_resume path

Pull vfs fixes from Al Viro:
 "Assorted fixes + unifying __d_move() and __d_materialise_dentry() +
  minimal regression fix for d_path() of victims of overwriting rename()
  ported on top of that"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: Don't exchange "short" filenames unconditionally.
  fold swapping ->d_name.hash into switch_names()
  fold unlocking the children into dentry_unlock_parents_for_move()
  kill __d_materialise_dentry()
  __d_materialise_dentry(): flip the order of arguments
  __d_move(): fold manipulations with ->d_child/->d_subdirs
  don't open-code d_rehash() in d_materialise_unique()
  pull rehashing and unlocking the target dentry into __d_materialise_dentry()
  ufs: deal with nfsd/iget races
  fuse: honour max_read and max_write in direct_io mode
  shmem: fix nlink for rename overwrite directory

Pull cgroup fixes from Tejun Heo:
 "This is quite late but these need to be backported anyway.

  This is the fix for a long-standing cpuset bug which existed from
  2009.  cpuset makes use of PF_SPREAD_{PAGE|SLAB} flags to modify the
  task's memory allocation behavior according to the settings of the
  cpuset it belongs to; unfortunately, when those flags have to be
  changed, cpuset did so directly even whlie the target task is running,
  which is obviously racy as task->flags may be modified by the task
  itself at any time.  This obscure bug manifested as corrupt
  PF_USED_MATH flag leading to a weird crash.

  The bug is fixed by moving the flag to task->atomic_flags.  The first
  two are prepatory ones to help defining atomic_flags accessors and the
  third one is the actual fix"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags
  sched: add macros to define bitops for task atomic flags
  sched: fix confusing PFA_NO_NEW_PRIVS constant

Pull ARM SoC fixes from Olof Johansson:
 "Here's our last set of fixes for 3.17.  Most of these are for TI
  platforms, fixing some noisy Kconfig issues, runtime clock and power
  issues on several platforms and NAND timings on DRA7.

  There are also a couple of bug fixes for i.MX, one for QCOM and a
 small fix to avoid section mismatch noise on PXA.

  Diffstat looks large, partially due to some tables being updated and
  thus touching many lines.  The qcom gsbi change also restructures
  clock management a bit and thus touches a bunch of lines.

  All in all, a bit more changes than we'd like at this point, but
  nothing stands out as risky either so it seems like the right thing to
  send it up now instead of holding it to the merge window"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  drivers/soc: qcom: do not disable the iface clock in probe
  ARM: imx: fix .is_enabled() of shared gate clock
  ARM: OMAP3: Fix I/O chain clock line assertion timed out error
  ARM: keystone: dts: fix bindings for pcie and usb clock nodes
  bus: omap_l3_noc: Fix connID for OMAP4
  ARM: DT: imx53: fix lvds channel 1 port
  ARM: dts: cm-t54: fix serial console power supply.
  ARM: dts: dra7-evm: Fix NAND GPMC timings
  ARM: pxa: fix section mismatch warning for pxa_timer_nodt_init
  ARM: OMAP: Fix Kconfig warning for omap1

Pull MIPS fixes from Ralf Baechle:
 "The final round of fixes.  One corner case in the math emulator and
  another one in the mcount function for ftrace"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: mcount: Adjust stack pointer for static trace in MIPS32
  MIPS: Fix MFC1 & MFHC1 emulation for 64-bit MIPS systems

Pull x86 fixes from Ingo Molnar:
 "This has:

   - EFI revert to fix a boot regression
   - early_ioremap() fix for boot failure
   - KASLR fix for possible boot failures
   - EFI fix for corrupted string printing
   - remove a misleading EFI bootup 'failed!' error message

  Unfortunately it's all rather close to the merge window"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Truncate 64-bit values when calling 32-bit OutputString()
  x86/efi: Delete misleading efi_printk() error message
  Revert "efi/x86: efistub: Move shared dependencies to <asm/efi.h>"
  x86/kaslr: Avoid the setup_data area when picking location
  x86 early_ioremap: Increase FIX_BTMAPS_SLOTS to 8

Only exchange source and destination filenames
if flags contain RENAME_EXCHANGE.
In case if executable file was running and replaced by
other file /proc/PID/exe should still show correct file name,
not the old name of the file by which it was replaced.

The scenario when this bug manifests itself was like this:
* ALT Linux uses rpm and start-stop-daemon;
* during a package upgrade rpm creates a temporary file
  for an executable to rename it upon successful unpacking;
* start-stop-daemon is run subsequently and it obtains
  the (nonexistant) temporary filename via /proc/PID/exe
  thus failing to identify the running process.

Note that "long" filenames (> DNAiME_INLINE_LEN) are still
exchanged without RENAME_EXCHANGE and this behaviour exists
long enough (should be fixed too apparently).
So this patch is just an interim workaround that restores
behavior for "short" names as it was before changes
introduced by commit da1ce067 ("vfs: add cross-rename").

See https://lkml.org/lkml/2014/9/7/6 for details.

AV: the comments about being more careful with ->d_name.hash
than with ->d_name.name are from back in 2.3.40s; they
became obsolete by 2.3.60s, when we started to unhash the
target instead of swapping hash chain positions followed
by d_delete() as we used to do when dcache was first
introduced.
Acked-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: da1ce067 "vfs: add cross-rename"
Signed-off-by: NMikhail Efremov <sem@altlinux.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

and do it along with ->d_name.len there
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... renaming it into dentry_unlock_for_move() and making it more
symmetric with dentry_lock_for_move().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

it folds into __d_move() now
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... thus making it much closer to (now unreachable, BTW) IS_ROOT(dentry)
case in __d_move().  A bit more and it'll fold in.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

list_del() + list_add() is a slightly pessimised list_move()
list_del() + INIT_LIST_HEAD() is a slightly pessimised list_del_init()

Interleaving those makes the resulting code even worse.  And harder to follow...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and get rid of duplicate BUG_ON() there
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The third argument of fuse_get_user_pages() "nbytesp" refers to the number of
bytes a caller asked to pack into fuse request. This value may be lesser
than capacity of fuse request or iov_iter.  So fuse_get_user_pages() must
ensure that *nbytesp won't grow.

Now, when helper iov_iter_get_pages() performs all hard work of extracting
pages from iov_iter, it can be done by passing properly calculated
"maxsize" to the helper.

The other caller of iov_iter_get_pages() (dio_refill_pages()) doesn't need
this capability, so pass LONG_MAX as the maxsize argument here.

Fixes: c9c37e2e ("fuse: switch to iov_iter_get_pages()")
Reported-by: NWerner Baumann <werner.baumann@onlinehome.de>
Tested-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If overwriting an empty directory with rename, then need to drop the extra
nlink.

Test prog:

#include <stdio.h>
#include <fcntl.h>
#include <err.h>
#include <sys/stat.h>

int main(void)
{
	const char *test_dir1 = "test-dir1";
	const char *test_dir2 = "test-dir2";
	int res;
	int fd;
	struct stat statbuf;

	res = mkdir(test_dir1, 0777);
	if (res == -1)
		err(1, "mkdir(\"%s\")", test_dir1);

	res = mkdir(test_dir2, 0777);
	if (res == -1)
		err(1, "mkdir(\"%s\")", test_dir2);

	fd = open(test_dir2, O_RDONLY);
	if (fd == -1)
		err(1, "open(\"%s\")", test_dir2);

	res = rename(test_dir1, test_dir2);
	if (res == -1)
		err(1, "rename(\"%s\", \"%s\")", test_dir1, test_dir2);

	res = fstat(fd, &statbuf);
	if (res == -1)
		err(1, "fstat(%i)", fd);

	if (statbuf.st_nlink != 0) {
		fprintf(stderr, "nlink is %lu, should be 0\n", statbuf.st_nlink);
		return 1;
	}

	return 0;
}
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pull input fix from Dmitry Torokhov:
 "A small fixup to i8042 adding Asus X450LCP to the nomux list"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: i8042 - fix Asus X450LCP touchpad detection

Pull scheduler fixes from Ingo Molnar:
 "A CONFIG_STACK_GROWSUP=y fix, and a hotplug llc CPU mask fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix unreleased llc_shared_mask bit during CPU hotplug
  sched: Fix end_of_stack() and location of stack canary for architectures using CONFIG_STACK_GROWSUP

Merge fixes from Andrew Morton:
 "9 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: softdirty: keep bit when zapping file pte
  fs/cachefiles: add missing \n to kerror conversions
  genalloc: fix device node resource counter
  drivers/rtc/rtc-efi.c: add missing module alias
  mm, slab: initialize object alignment on cache creation
  mm: softdirty: addresses before VMAs in PTE holes aren't softdirty
  ocfs2/dlm: do not get resource spinlock if lockres is new
  nilfs2: fix data loss with mmap()
  ocfs2: free vol_label in ocfs2_delete_osb()

This fixes the same bug as b43790ee ("mm: softdirty: don't forget to
save file map softdiry bit on unmap") and 9aed8614 ("mm/memory.c:
don't forget to set softdirty on file mapped fault") where the return
value of pte_*mksoft_dirty was being ignored.

To be sure that no other pte/pmd "mk" function return values were being
ignored, I annotated the functions in arch/x86/include/asm/pgtable.h
with __must_check and rebuilt.

The userspace effect of this bug is that the softdirty mark might be
lost if a file mapped pte get zapped.
Signed-off-by: NPeter Feiner <pfeiner@google.com>
Acked-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>	[3.12+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 0227d6ab ("fs/cachefiles: replace kerror by pr_err") didn't
include newline featuring in original kerror definition
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Reported-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org>	[3.16.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Decrement the np_pool device_node refcount, which was incremented on
the preceding of_parse_phandle() call.
Signed-off-by: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Without proper alias kernel module is not loaded for rtc-efi driver.
Signed-off-by: NPali Rohár <pali.rohar@gmail.com>
Cc: dann frazier <dannf@dannf.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit 45906855 ("mm/sl[aou]b: Common alignment code"), the
"ralign" automatic variable in __kmem_cache_create() may be used as
uninitialized.

The proper alignment defaults to BYTES_PER_WORD and can be overridden by
SLAB_RED_ZONE or the alignment specified by the caller.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=85031Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reported-by: NAndrei Elovikov <a.elovikov@gmail.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>