This flag is a NOOP and can be removed now.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>

As described in e6fa16ab ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check whether the signal we're about to block
is pending in the shared queue.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>

Bugfix for following error messages:
lib/iomap.c: In function 'pci_iomap':
lib/iomap.c:274: error: implicit declaration of function 'ioremap_nocache'
lib/iomap.c:274: warning: return makes pointer from integer without a cast

Also see commit <f1ecc698>
  it will hide the ioremap_nocache function for systems with an MMU
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jonas Bonn <jonas@southpole.se>

For the commit <f1ecc698> has changed
xlate_dev_mem_ptr definition in asm-generic/io.h for the systems with
an MMU, so delete it from unicore32 specified io.h.
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jonas Bonn <jonas@southpole.se>

In the file drivers/of/fdt.c, it uses the COMMAND_LINE_SIZE which is stated
in asm/setup.h, so asm/setup.h should be included in drivers/of/fdt.c.
Signed-off-by: Yu Yue <yuyue@mprc.pku.edu.cn>
Signed-off-by: Guan Xuetao <guanxuetao@mprc.pku.edu.cn>

Cc: Grant Likerly <grant.likely@secretlab.ca>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Arnd Bergmann <arnd@arndb.de>

All other ports use "Kernel code" to identify the Kernel text segment
in /proc/iomem. Change the unicore32 resources to do the same.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ext[34]: avoid i_nlink warnings triggered by drop_nlink/inc_nlink kludge in symlink()
  exofs: oops after late failure in mount
  devpts: fix double-free on mount failure
  ... and the same for gadgetfs
  functionfs: unfuck failure exits on mount

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (31 commits)
  [S390] disassembler: mark exception causing instructions
  [S390] Enable exception traces by default
  [S390] return address of compat signals
  [S390] sysctl: get rid of dead declaration
  [S390] dasd: fix fixpoint divide exception in define_extent
  [S390] dasd: add sanity check to detect path connection error
  [S390] qdio: fix kernel panic for zfcp 31-bit
  [S390] Add s390x description to Documentation/kdump/kdump.txt
  [S390] Add VMCOREINFO_SYMBOL(high_memory) to vmcoreinfo
  [S390] dasd: fix expiration handling for recovery requests
  [S390] outstanding interrupts vs. smp_send_stop
  [S390] ipc: call generic sys_ipc demultiplexer
  [S390] zcrypt: Fix error return codes.
  [S390] zcrypt: Rework length parameter checking.
  [S390] cleanup trap handling
  [S390] Remove Kerntypes leftovers
  [S390] topology: increase poll frequency if change is anticipated
  [S390] entry[64].S improvements
  [S390] make arch/s390 subdirectories depend on config option
  [S390] kvm: move cmf host id constant out of lowcore
  ...

Fix up conflicts in arch/s390/kernel/{smp.c,topology.c} due to the
sysdev removal clashing with "topology: get rid of ifdefs" which moved
some of that code around.

Both ext3 and ext4 put the half-created symlink inode into the orphan list
for a while (see the comment in ext[34]_symlink() for gory details).  Then,
if everything went fine, they pull it out of the orphan list and bump the
link count back to 1.  The thing is, inc_nlink() is going to complain about
seeing somebody changing i_nlink from 0 to 1.  With a good reason, since
normally something like that is a bug.  Explicit set_nlink(inode, 1) does
the same thing as inc_nlink() here, but it does *not* complain - exactly
because it should be usable in strange situations like this one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

We have already set ->s_root, so ->put_super() is going to be called.
Freeing ->s_fs_info is a bloody bad idea when it's going to be
dereferenced very shortly...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devpts_kill_sb() is called even if devpts_fill_super() fails;
we should not do that kfree() in the latter, especially not
with ->s_fs_info left pointing to freed object.  Double kfree()
is a Bad Thing(tm)...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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

* if you do dput() of root dentry, do *not* follow that with iput() of root
inode.
* while we are at it, don't do that dput() at all - you are leaving the pointer
in ->s_root and your ->kill_sb() will be very unhappy with that.  It will do
proper dput(), though, so the easiest way is to leave that to it entirely.
* freeing ->s_fs_info is also best left to ->kill_sb() (which will do it
anyway), especially since we leave the pointer in place.
* that xchg() in ->kill_sb() is not a bug per se, but it's a plain and simple
masturbation with fewer excuses than Onan had...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

A call to va_copy() should always be followed by a call to va_end() in
the same function.  In kernel/autit.c::audit_log_vformat() this is not
always done.  This patch makes sure va_end() is always called.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We leak in drivers/scsi/aacraid/commctrl.c::aac_send_raw_srb() :

We allocate memory:

	...
	struct user_sgmap* usg;
	usg = kmalloc(actual_fibsize - sizeof(struct aac_srb)
	  + sizeof(struct sgmap), GFP_KERNEL);

and then neglect to free it:

	...
	for (i = 0; i < usg->count; i++) {
		u64 addr;
		void* p;
		if (usg->sg[i].count >
		    ((dev->adapter_info.options &
		     AAC_OPT_NEW_COMM) ?
		      (dev->scsi_host_ptr->max_sectors << 9) :
		      65536)) {
			rcode = -EINVAL;
			goto cleanup;
	... this 'goto' makes 'usg' go out of scope and leak the memory we
	    allocated.

Other exits properly kfree(usg), it's just here it is neglected.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

infiniband changes for 3.3 merge window

* tag 'infiniband-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  rdma/core: Fix sparse warnings
  RDMA/cma: Fix endianness bugs
  RDMA/nes: Fix terminate during AE
  RDMA/nes: Make unnecessarily global nes_set_pau() static
  RDMA/nes: Change MDIO bus clock to 2.5MHz
  IB/cm: Fix layout of APR message
  IB/mlx4: Fix SL to 802.1Q priority-bits mapping for IBoE
  IB/qib: Default some module parameters optimally
  IB/qib: Optimize locking for get_txreq()
  IB/qib: Fix a possible data corruption when receiving packets
  IB/qib: Eliminate 64-bit jiffies use
  IB/qib: Fix style issues
  IB/uverbs: Protect QP multicast list

* 'dma-buf-merge' of git://people.freedesktop.org/~airlied/linux:
  dma-buf: mark EXPERIMENTAL for 1st release.
  dma-buf: Documentation for buffer sharing framework
  dma-buf: Introduce dma buffer sharing mechanism

Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  max1111.c: fix checkpatch warning
  hwmon: (lm75) fix checkpatch warnings
  hwmon: (lm80) fix checkpatch messages
  hwmon: replaced strict_str* with kstr*
  hwmon: (lm75) fix checkpatch warning
  hwmon: (lm75) added error handling
  hwmon: (ltc4261) set data->valid to 0 if error
  hwmon: (f75375s) Add support for F75387SG/RG
  hwmon: (f75375s) Disable setting DC fan control mode for F75373
  hwmon: (f75375s) Initialize pwmX_mode and pwmX_enable if there is no platform data
  hwmon: (f75375s) Fix value range for PWM modes
  hwmon: (f75375s) Use standard sysfs attribute names
  hwmon: (f75375s) Fix checkpatch errors and warnings
  hwmon: (pmbus/zl6100) Only instantiate external temperature sensor if enabled
  hwmon: (pmbus/zl6100) Add support for Ericsson BMR45[0,1] and BMR46[2,3,4]
  hwmon: (pmbus/zl6100) Add support for ZL2005
  hwmon: (pmbus/adm1275) Validate device ID

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap: (36 commits)
  mfd: Clearing events requires event registers to be writable for da9052-core
  mfd: Fix annotations in da9052-core
  gpiolib: Mark da9052 driver broken
  mfd: Declare da9052_regmap_config for the bus drivers
  MFD: DA9052/53 MFD core module add SPI support v2
  MFD: DA9052/53 MFD core module
  regmap: Add irq_base accessor to regmap_irq
  regmap: Allow drivers to reinitialise the register cache at runtime
  regmap: Add trace event for successful cache reads
  regmap: Allow regmap_update_bits() users to detect changes
  regmap: Report if we actually handled an interrupt in regmap-irq
  regmap: Fix rbtreee build when not using debugfs
  regmap: Provide debugfs dump of the rbtree cache data
  regmap: Do debugfs init before cache init
  regmap: Suppress noop writes in regmap_update_bits()
  regmap: Remove indexed cache type
  regmap: Drop check whether a register is readable in regcache_read
  regmap: Properly round cache_word_size
  regmap: Add support for 10/14 register formating
  regmap: Try cached read before checking if a hardware read is possible
  ...

md update for 3.3

Big change is new hot-replacement.
A slot in an array can hold 2 devices - one that
wants-replacement and one that is the replacement.
Once the replacement is built - either from the
original or (in the case of errors) from elsewhere,
the wants-replacement device will be removed.

* tag 'md-3.3' of git://neil.brown.name/md: (36 commits)
  md/raid1: Mark device want_replacement when we see a write error.
  md/raid1: If there is a spare and a want_replacement device, start replacement.
  md/raid1: recognise replacements when assembling arrays.
  md/raid1: handle activation of replacement device when recovery completes.
  md/raid1: Allow a failed replacement device to be removed.
  md/raid1: Allocate spare to store replacement devices and their bios.
  md/raid1:  Replace use of mddev->raid_disks with conf->raid_disks.
  md/raid10: If there is a spare and a want_replacement device, start replacement.
  md/raid10: recognise replacements when assembling array.
  md/raid10: Allow replacement device to be replace old drive.
  md/raid10: handle recovery of replacement devices.
  md/raid10:  Handle replacement devices during resync.
  md/raid10: writes should get directed to replacement as well as original.
  md/raid10: allow removal of failed replacement devices.
  md/raid10: preferentially read from replacement device if possible.
  md/raid10:  change read_balance to return an rdev
  md/raid10: prepare data structures for handling replacement.
  md/raid5: Mark device want_replacement when we see a write error.
  md/raid5: If there is a spare and a want_replacement device, start replacement.
  md/raid5: recognise replacements when assembling array.
  ...

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits)
  Kconfig: acpi: Fix typo in comment.
  misc latin1 to utf8 conversions
  devres: Fix a typo in devm_kfree comment
  btrfs: free-space-cache.c: remove extra semicolon.
  fat: Spelling s/obsolate/obsolete/g
  SCSI, pmcraid: Fix spelling error in a pmcraid_err() call
  tools/power turbostat: update fields in manpage
  mac80211: drop spelling fix
  types.h: fix comment spelling for 'architectures'
  typo fixes: aera -> area, exntension -> extension
  devices.txt: Fix typo of 'VMware'.
  sis900: Fix enum typo 'sis900_rx_bufer_status'
  decompress_bunzip2: remove invalid vi modeline
  treewide: Fix comment and string typo 'bufer'
  hyper-v: Update MAINTAINERS
  treewide: Fix typos in various parts of the kernel, and fix some comments.
  clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR
  gpio: Kconfig: drop unknown symbol 'CS5535_GPIO'
  leds: Kconfig: Fix typo 'D2NET_V2'
  sound: Kconfig: drop unknown symbol ARCH_CLPS7500
  ...

Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new
kconfig additions, close to removed commented-out old ones)

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/apm:
  x86: Kconfig: drop unknown symbol 'APM_MODULE'

* 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (76 commits)
  PM / Hibernate: Implement compat_ioctl for /dev/snapshot
  PM / Freezer: fix return value of freezable_schedule_timeout_killable()
  PM / shmobile: Allow the A4R domain to be turned off at run time
  PM / input / touchscreen: Make st1232 use device PM QoS constraints
  PM / QoS: Introduce dev_pm_qos_add_ancestor_request()
  PM / shmobile: Remove the stay_on flag from SH7372's PM domains
  PM / shmobile: Don't include SH7372's INTCS in syscore suspend/resume
  PM / shmobile: Add support for the sh7372 A4S power domain / sleep mode
  PM: Drop generic_subsys_pm_ops
  PM / Sleep: Remove forward-only callbacks from AMBA bus type
  PM / Sleep: Remove forward-only callbacks from platform bus type
  PM: Run the driver callback directly if the subsystem one is not there
  PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers
  PM/Devfreq: Add Exynos4-bus device DVFS driver for Exynos4210/4212/4412.
  PM / Sleep: Merge internal functions in generic_ops.c
  PM / Sleep: Simplify generic system suspend callbacks
  PM / Hibernate: Remove deprecated hibernation snapshot ioctls
  PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()
  ARM: S3C64XX: Implement basic power domain support
  PM / shmobile: Use common always on power domain governor
  ...

Fix up trivial conflict in fs/xfs/xfs_buf.c due to removal of unused
XBT_FORCE_SLEEP bit

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
  GFS2: local functions should be static
  GFS2: We only need one ACL getting function
  GFS2: Fix multi-block allocation
  GFS2: decouple quota allocations from block allocations
  GFS2: split function rgblk_search
  GFS2: Fix up "off by one" in the previous patch
  GFS2: move toward a generic multi-block allocator
  GFS2: O_(D)SYNC support for fallocate
  GFS2: remove vestigial al_alloced
  GFS2: combine gfs2_alloc_block and gfs2_alloc_di
  GFS2: Add non-try locks back to get_local_rgrp
  GFS2: f_ra is always valid in dir readahead function
  GFS2: Fix very unlikley memory leak in ACL xattr code
  GFS2: More automated code analysis fixes
  GFS2: Add readahead to sequential directory traversal
  GFS2: Fix up REQ flags

* 'for-linus' of git://oss.sgi.com/xfs/xfs: (22 commits)
  xfs: mark the xfssyncd workqueue as non-reentrant
  xfs: simplify xfs_qm_detach_gdquots
  xfs: fix acl count validation in xfs_acl_from_disk()
  xfs: remove unused XBT_FORCE_SLEEP bit
  xfs: remove XFS_QMOPT_DQSUSER
  xfs: kill xfs_qm_idtodq
  xfs: merge xfs_qm_dqinit_core into the only caller
  xfs: add a xfs_dqhold helper
  xfs: simplify xfs_qm_dqattach_grouphint
  xfs: nest qm_dqfrlist_lock inside the dquot qlock
  xfs: flatten the dquot lock ordering
  xfs: implement lazy removal for the dquot freelist
  xfs: remove XFS_DQ_INACTIVE
  xfs: cleanup xfs_qm_dqlookup
  xfs: cleanup dquot locking helpers
  xfs: remove the sync_mode argument to xfs_qm_dqflush_all
  xfs: remove xfs_qm_sync
  xfs: make sure to really flush all dquots in xfs_qm_quotacheck
  xfs: untangle SYNC_WAIT and SYNC_TRYLOCK meanings for xfs_qm_dqflush
  xfs: remove the lid_size field in struct log_item_desc
  ...

Fix up trivial conflict in fs/xfs/xfs_sync.c

* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits)
  reiserfs: Properly display mount options in /proc/mounts
  vfs: prevent remount read-only if pending removes
  vfs: count unlinked inodes
  vfs: protect remounting superblock read-only
  vfs: keep list of mounts for each superblock
  vfs: switch ->show_options() to struct dentry *
  vfs: switch ->show_path() to struct dentry *
  vfs: switch ->show_devname() to struct dentry *
  vfs: switch ->show_stats to struct dentry *
  switch security_path_chmod() to struct path *
  vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
  vfs: trim includes a bit
  switch mnt_namespace ->root to struct mount
  vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
  vfs: opencode mntget() mnt_set_mountpoint()
  vfs: spread struct mount - remaining argument of next_mnt()
  vfs: move fsnotify junk to struct mount
  vfs: move mnt_devname
  vfs: move mnt_list to struct mount
  vfs: switch pnode.h macros to struct mount *
  ...

devicetree/next changes queued for v3.3 merge window

* tag 'devicetree-for-linus-20120104' of git://git.secretlab.ca/git/linux-2.6:
  ARM: prom.h: Fix build error by removing unneeded header file
  irq: check domain hwirq range for DT translate
  dt: add empty of_get_node/of_put_node functions
  of/pdt: fix section mismatch warning
  i2c-designware: add OF binding support
  dt/i2c: Enumerate some of the known trivial i2c devices
  dt: reform for_each_property to for_each_property_of_node
  ARM/of: allow *machine_desc.dt_compat to be const
  of/base: Take NULL string into account for property with multiple strings
  OF/device-tree: Add some entries to vendor-prefixes.txt

Fix up trivial add-add conflicts in include/linux/of.h

spi changes queued up for v3.3 merge window

* tag 'spi-for-linus-20120104' of git://git.secretlab.ca/git/linux-2.6:
  spi: Fix device unregistration when unregistering the bus master
  spi-topcliff-pch: Change company name OKI SEMICONDUCTOR to LAPIS Semiconductor
  spi-topcliff-pch: Support new device LAPIS Semiconductor ML7831 IOH
  spi/omap: Correct the error path
  spi/omap: call pm_runtime_disable in error path and remove
  spi/omap: Use a workqueue per omap2_mcspi controller

Changes queued in gpio/next for the start of the 3.3 merge window

* tag 'gpio-for-linus-20120104' of git://git.secretlab.ca/git/linux-2.6:
  gpio: Add decode of WM8994 GPIO configuration
  gpio: Convert GPIO drivers to module_platform_driver
  gpio: Fix typo in comment in Samsung driver
  gpio: Explicitly index samsung_gpio_cfgs
  gpio: Add Linus Walleij as gpio co-maintainer
  of: Add device tree selftests
  of: create of_phandle_args to simplify return of phandle parsing data
  gpio/powerpc: Eliminate duplication of of_get_named_gpio_flags()
  gpio/microblaze: Eliminate duplication of of_get_named_gpio_flags()
  gpiolib: output basic details and consolidate gpio device drivers
  pch_gpio: Change company name OKI SEMICONDUCTOR to LAPIS Semiconductor
  pch_gpio: Support new device LAPIS Semiconductor ML7831 IOH
  spi/pl022: make the chip deselect handling thread safe
  spi/pl022: add support for pm_runtime autosuspend
  spi/pl022: disable the PL022 block when unused
  spi/pl022: move device disable to workqueue thread
  spi/pl022: skip default configuration before suspending
  spi/pl022: fix build warnings
  spi/pl022: only enable RX interrupts when TX is complete

* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits)
  arm: fix up some samsung merge sysdev conversion problems
  firmware: Fix an oops on reading fw_priv->fw in sysfs loading file
  Drivers:hv: Fix a bug in vmbus_driver_unregister()
  driver core: remove __must_check from device_create_file
  debugfs: add missing #ifdef HAS_IOMEM
  arm: time.h: remove device.h #include
  driver-core: remove sysdev.h usage.
  clockevents: remove sysdev.h
  arm: convert sysdev_class to a regular subsystem
  arm: leds: convert sysdev_class to a regular subsystem
  kobject: remove kset_find_obj_hinted()
  m86k: gpio - convert sysdev_class to a regular subsystem
  mips: txx9_sram - convert sysdev_class to a regular subsystem
  mips: 7segled - convert sysdev_class to a regular subsystem
  sh: dma - convert sysdev_class to a regular subsystem
  sh: intc - convert sysdev_class to a regular subsystem
  power: suspend - convert sysdev_class to a regular subsystem
  power: qe_ic - convert sysdev_class to a regular subsystem
  power: cmm - convert sysdev_class to a regular subsystem
  s390: time - convert sysdev_class to a regular subsystem
  ...

Fix up conflicts with 'struct sysdev' removal from various platform
drivers that got changed:
 - arch/arm/mach-exynos/cpu.c
 - arch/arm/mach-exynos/irq-eint.c
 - arch/arm/mach-s3c64xx/common.c
 - arch/arm/mach-s3c64xx/cpu.c
 - arch/arm/mach-s5p64x0/cpu.c
 - arch/arm/mach-s5pv210/common.c
 - arch/arm/plat-samsung/include/plat/cpu.h
 - arch/powerpc/kernel/sysfs.c
and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h

Make reiserfs properly display mount options in /proc/mounts.

CC: reiserfs-devel@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

If there are any inodes on the super block that have been unlinked
(i_nlink == 0) but have not yet been deleted then prevent the
remounting the super block read-only.
Reported-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add a new counter to the superblock that keeps track of unlinked but
not yet deleted inodes.

Do not WARN_ON if set_nlink is called with zero count, just do a
ratelimited printk.  This happens on xfs and probably other
filesystems after an unclean shutdown when the filesystem reads inodes
which already have zero i_nlink.  Reported by Christoph Hellwig.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Currently remouting superblock read-only is racy in a major way.

With the per mount read-only infrastructure it is now possible to
prevent most races, which this patch attempts.

Before starting the remount read-only, iterate through all mounts
belonging to the superblock and if none of them have any pending
writes, set sb->s_readonly_remount.  This indicates that remount is in
progress and no further write requests are allowed.  If the remount
succeeds set MS_RDONLY and reset s_readonly_remount.

If the remounting is unsuccessful just reset s_readonly_remount.
This can result in transient EROFS errors, despite the fact the
remount failed.  Unfortunately hodling off writes is difficult as
remount itself may touch the filesystem (e.g. through load_nls())
which would deadlock.

A later patch deals with delayed writes due to nlink going to zero.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Keep track of vfsmounts belonging to a superblock.  List is protected
by vfsmount_lock.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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

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

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

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

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