cpufreq: interactive: Move definition of cpufreq_gov_interactive downwards

This moves definition of cpufreq_gov_interactive towards the bottom of file, so
that we don't have to add prototype of cpufreq_governor_interactive() in the
beginning of file.

Change-Id: I04bd1004954eb36502c5cd7e35d3d7274cddaf95
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Git-commit: e50d640cacfe61e69f1b4fa92fa0174c688e919c
Git-Repo: https://android.googlesource.com/kernel/common.git
[junjiew@codeaurora.org: Resolve merge conflicts]
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: Move get_cpu_idle_time() to cpufreq.c

Governors other than ondemand and conservative can also use
get_cpu_idle_time() and they aren't required to compile
cpufreq_governor.c. So, move these independent routines to
cpufreq.c instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: 72a4ce340a7ebf39e1c6fdc8f5feb4f974d6c635
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[junjiew@codeaurora.org: update non-upstream files]
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

Change-Id: I3227454599250011a19a752c962e3cacb1fb0301
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	drivers/cpufreq/cpufreq.c
soc: qcom: rq_stats: remove the redundant iowait check

Iowait_time check is redundant and it would lead to heavy load
due to miscaluculation of idle time. Hence remove this check
as iowait will considered based on io_busy flag.

Change-Id: I4dd9f9c79205eca588daea8cc0fe892394a83391
CRs-fixed: 662052
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/arm/mach-msm/msm_rq_stats.c
mm, oom: change type of oom_score_adj to short

The maximum oom_score_adj is 1000 and the minimum oom_score_adj is -1000,
so this range can be represented by the signed short type with no
functional change.  The extra space this frees up in struct signal_struct
will be used for per-thread oom kill flags in the next patch.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Blechd0se <alex.christ@hotmail.de>

Conflicts:
	drivers/staging/android/lowmemorykiller.c
	fs/proc/base.c
	include/linux/sched.h
	mm/oom_kill.c
	mm/swapfile.c

Conflicts:
	drivers/staging/android/lowmemorykiller.c
mm, oom: fix race when specifying a thread as the oom origin

test_set_oom_score_adj() and compare_swap_oom_score_adj() are used to
specify that current should be killed first if an oom condition occurs in
between the two calls.

The usage is

	short oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
	...
	compare_swap_oom_score_adj(OOM_SCORE_ADJ_MAX, oom_score_adj);

to store the thread's oom_score_adj, temporarily change it to the maximum
score possible, and then restore the old value if it is still the same.

This happens to still be racy, however, if the user writes
OOM_SCORE_ADJ_MAX to /proc/pid/oom_score_adj in between the two calls.
The compare_swap_oom_score_adj() will then incorrectly reset the old value
prior to the write of OOM_SCORE_ADJ_MAX.

To fix this, introduce a new oom_flags_t member in struct signal_struct
that will be used for per-thread oom killer flags.  KSM and swapoff can
now use a bit in this member to specify that threads should be killed
first in oom conditions without playing around with oom_score_adj.

This also allows the correct oom_score_adj to always be shown when reading
/proc/pid/oom_score.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Blechd0se <alex.christ@hotmail.de>

Conflicts:
	include/linux/sched.h
	mm/oom_kill.c
	mm/swapfile.c
mm, oom: cleanup pagefault oom handler

To lock the entire system from parallel oom killing, it's possible to pass
in a zonelist with all zones rather than using for_each_populated_zone()
for the iteration.  This obsoletes try_set_system_oom() and
clear_system_oom() so that they can be removed.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Blechd0se <alex.christ@hotmail.de>
mm, oom: remove redundant sleep in pagefault oom handler

out_of_memory() will already cause current to schedule if it has not been
killed, so doing it again in pagefault_out_of_memory() is redundant.
Remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Blechd0se <alex.christ@hotmail.de>
staging: android: reclaim some ram from logger
ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions

This patch implements the word-at-a-time interface for ARM using the
same algorithm as x86. We use the fls macro from ARMv5 onwards, where
we have a clz instruction available which saves us a mov instruction
when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001
constant. Big-endian configurations make use of the implementation from
asm-generic.

With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.

Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

lib: Sparc's strncpy_from_user is generic enough, move under lib/

To use this, an architecture simply needs to:

1) Provide a user_addr_max() implementation via asm/uaccess.h

2) Add "select GENERIC_STRNCPY_FROM_USER" to their arch Kcnfig

3) Remove the existing strncpy_from_user() implementation and symbol
   exports their architecture had.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: David Howells <dhowells@redhat.com>

lib: add generic strnlen_user() function

This adds a new generic optimized strnlen_user() function that uses the
<asm/word-at-a-time.h> infrastructure to portably do efficient string
handling.

In many ways, strnlen is much simpler than strncpy, and in particular we
can always pre-align the words we load from memory.  That means that all
the worries about alignment etc are a non-issue, so this one can easily
be used on any architecture.  You obviously do have to do the
appropriate word-at-a-time.h macros.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel: Move REPEAT_BYTE definition into linux/kernel.h

And make sure that everything using it explicitly includes
that header file.

Signed-off-by: David S. Miller <davem@davemloft.net>

word-at-a-time: make the interfaces truly generic

This changes the interfaces in <asm/word-at-a-time.h> to be a bit more
complicated, but a lot more generic.

In particular, it allows us to really do the operations efficiently on
both little-endian and big-endian machines, pretty much regardless of
machine details.  For example, if you can rely on a fast population
count instruction on your architecture, this will allow you to make your
optimized <asm/word-at-a-time.h> file with that.

NOTE! The "generic" version in include/asm-generic/word-at-a-time.h is
not truly generic, it actually only works on big-endian.  Why? Because
on little-endian the generic algorithms are wasteful, since you can
inevitably do better. The x86 implementation is an example of that.

(The only truly non-generic part of the asm-generic implementation is
the "find_zero()" function, and you could make a little-endian version
of it.  And if the Kbuild infrastructure allowed us to pick a particular
header file, that would be lovely)

The <asm/word-at-a-time.h> functions are as follows:

 - WORD_AT_A_TIME_CONSTANTS: specific constants that the algorithm
   uses.

 - has_zero(): take a word, and determine if it has a zero byte in it.
   It gets the word, the pointer to the constant pool, and a pointer to
   an intermediate "data" field it can set.

   This is the "quick-and-dirty" zero tester: it's what is run inside
   the hot loops.

 - "prep_zero_mask()": take the word, the data that has_zero() produced,
   and the constant pool, and generate an *exact* mask of which byte had
   the first zero.  This is run directly *outside* the loop, and allows
   the "has_zero()" function to answer the "is there a zero byte"
   question without necessarily getting exactly *which* byte is the
   first one to contain a zero.

   If you do multiple byte lookups concurrently (eg "hash_name()", which
   looks for both NUL and '/' bytes), after you've done the prep_zero_mask()
   phase, the result of those can be or'ed together to get the "either
   or" case.

 - The result from "prep_zero_mask()" can then be fed into "find_zero()"
   (to find the byte offset of the first byte that was zero) or into
   "zero_bytemask()" (to find the bytemask of the bytes preceding the
   zero byte).

   The existence of zero_bytemask() is optional, and is not necessary
   for the normal string routines.  But dentry name hashing needs it, so
   if you enable DENTRY_WORD_AT_A_TIME you need to expose it.

This changes the generic strncpy_from_user() function and the dentry
hashing functions to use these modified word-at-a-time interfaces.  This
gets us back to the optimized state of the x86 strncpy that we lost in
the previous commit when moving over to the generic version.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ARM: 7450/1: dcache: select DCACHE_WORD_ACCESS for little-endian ARMv6+ CPUs

DCACHE_WORD_ACCESS uses the word-at-a-time API for optimised string
comparisons in the vfs layer.

This patch implements support for load_unaligned_zeropad for ARM CPUs
with native support for unaligned memory accesses (v6+) when running
little-endian.

Change-Id: Ifdf8207f2581f93870eb0e627f5d12f97c4be7cc
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/arm/Kconfig
	arch/arm/lib/Makefile
f2fs: for coming update
f2fs: Pull in from upstream 3.13 kernel

Merge tag 'for-3.8-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull new F2FS filesystem from Jaegeuk Kim:
 "Introduce a new file system, Flash-Friendly File System (F2FS), to
  Linux 3.8.

  Highlights:
   - Add initial f2fs source codes
   - Fix an endian conversion bug
   - Fix build failures on random configs
   - Fix the power-off-recovery routine
   - Minor cleanup, coding style, and typos patches"

From the Kconfig help text:

  F2FS is based on Log-structured File System (LFS), which supports
  versatile "flash-friendly" features. The design has been focused on
  addressing the fundamental issues in LFS, which are snowball effect
  of wandering tree and high cleaning overhead.

  Since flash-based storages show different characteristics according to
  the internal geometry or flash memory management schemes aka FTL, F2FS
  and tools support various parameters not only for configuring on-disk
  layout, but also for selecting allocation and cleaning algorithms.

and there's an article by Neil Brown about it on lwn.net:

  http://lwn.net/Articles/518988/

* tag 'for-3.8-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (36 commits)
  f2fs: fix tracking parent inode number
  f2fs: cleanup the f2fs_bio_alloc routine
  f2fs: introduce accessor to retrieve number of dentry slots
  f2fs: remove redundant call to f2fs_put_page in delete entry
  f2fs: make use of GFP_F2FS_ZERO for setting gfp_mask
  f2fs: rewrite f2fs_bio_alloc to make it simpler
  f2fs: fix a typo in f2fs documentation
  f2fs: remove unused variable
  f2fs: move error condition for mkdir at proper place
  f2fs: remove unneeded initialization
  f2fs: check read only condition before beginning write out
  f2fs: remove unneeded memset from init_once
  f2fs: show error in case of invalid mount arguments
  f2fs: fix the compiler warning for uninitialized use of variable
  f2fs: resolve build failures
  f2fs: adjust kernel coding style
  f2fs: fix endian conversion bugs reported by sparse
  f2fs: remove unneeded version.h header file from f2fs.h
  f2fs: update the f2fs document
  f2fs: update Kconfig and Makefile
  ...

Conflicts:
	include/uapi/linux/magic.h

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs bug fixes from Jaegeuk Kim:
 "This patch-set includes two major bug fixes:
   - incorrect IUsed provided by *df -i*, and
   - lookup failure of parent inodes in corner cases.

  [Other Bug Fixes]
   - Fix error handling routines
   - Trigger recovery process correctly
   - Resolve build failures due to missing header files

  [Etc]
   - Add a MAINTAINERS entry for f2fs
   - Fix and clean up variables, functions, and equations
   - Avoid warnings during compilation"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs:
  f2fs: unify string length declarations and usage
  f2fs: clean up unused variables and return values
  f2fs: clean up the start_bidx_of_node function
  f2fs: remove unneeded variable from f2fs_sync_fs
  f2fs: fix fsync_inode list addition logic and avoid invalid access to memory
  f2fs: remove unneeded initialization of nr_dirty in dirty_seglist_info
  f2fs: handle error from f2fs_iget_nowait
  f2fs: fix equation of has_not_enough_free_secs()
  f2fs: add MAINTAINERS entry
  f2fs: return a default value for non-void function
  f2fs: invalidate the node page if allocation is failed
  f2fs: add missing #include <linux/prefetch.h>
  f2fs: do f2fs_balance_fs in front of dir operations
  f2fs: should recover orphan and fsync data
  f2fs: fix handling errors got by f2fs_write_inode
  f2fs: fix up f2fs_get_parent issue to retrieve correct parent inode number
  f2fs: fix wrong calculation on f_files in statfs
  f2fs: remove set_page_dirty for atomic f2fs_end_io_write

Merge tag 'f2fs-for-3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs fixes from Jaegeuk Kim:
 o Support swap file and link generic_file_remap_pages
 o Enhance the bio streaming flow and free section control
 o Major bug fix on recovery routine
 o Minor bug/warning fixes and code cleanups

* tag 'f2fs-for-3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (22 commits)
  f2fs: use _safe() version of list_for_each
  f2fs: add comments of start_bidx_of_node
  f2fs: avoid issuing small bios due to several dirty node pages
  f2fs: support swapfile
  f2fs: add remap_pages as generic_file_remap_pages
  f2fs: add __init to functions in init_f2fs_fs
  f2fs: fix the debugfs entry creation path
  f2fs: add global mutex_lock to protect f2fs_stat_list
  f2fs: remove the blk_plug usage in f2fs_write_data_pages
  f2fs: avoid redundant time update for parent directory in f2fs_delete_entry
  f2fs: remove redundant call to set_blocksize in f2fs_fill_super
  f2fs: move f2fs_balance_fs to punch_hole
  f2fs: add f2fs_balance_fs in several interfaces
  f2fs: revisit the f2fs_gc flow
  f2fs: check return value during recovery
  f2fs: avoid null dereference in f2fs_acl_from_disk
  f2fs: initialize newly allocated dnode structure
  f2fs: update f2fs partition info about SIT/NAT layout
  f2fs: update f2fs document to reflect SIT/NAT layout correctly
  f2fs: remove unneeded INIT_LIST_HEAD at few places
  ...

Merge tag 'f2fs-for-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs update from Jaegeuk Kim:
 "[Major bug fixes]
   o Store device file information correctly
   o Fix -EIO handling with respect to power-off-recovery
   o Allocate blocks with global locks
   o Fix wrong calculation of the SSR cost

  [Cleanups]
   o Get rid of fake on-stack dentries

  [Enhancement]
   o Support (un)freeze_fs
   o Enhance the f2fs_gc flow
   o Support 32-bit binary execution on 64-bit kernel"

* tag 'f2fs-for-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (29 commits)
  f2fs: avoid build warning
  f2fs: add compat_ioctl to provide backward compatability
  f2fs: fix calculation of max. gc cost in the SSR case
  f2fs: clarify and enhance the f2fs_gc flow
  f2fs: optimize the return condition for has_not_enough_free_secs
  f2fs: make an accessor to get sections for particular block type
  f2fs: mark gc_thread as NULL when thread creation is failed
  f2fs: name gc task as per the block device
  f2fs: remove unnecessary gc option check and balance_fs
  f2fs: remove repeated F2FS_SET_SB_DIRT call
  f2fs: when check superblock failed, try to check another superblock
  f2fs: use F2FS_BLKSIZE to judge bloksize and page_cache_size
  f2fs: add device name in debugfs
  f2fs: stop repeated checking if cp is needed
  f2fs: avoid balanc_fs during evict_inode
  f2fs: remove the use of page_cache_release
  f2fs: fix typo mistake for data_version description
  f2fs: reorganize code for ra_node_page
  f2fs: avoid redundant call to has_not_enough_free_secs in f2fs_gc
  f2fs: add un/freeze_fs into super_operations
  ...

Merge tag 'f2fs-for-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "This patch-set includes the following major enhancement patches.
   - introduce a new gloabl lock scheme
   - add tracepoints on several major functions
   - fix the overall cleaning process focused on victim selection
   - apply the block plugging to merge IOs as much as possible
   - enhance management of free nids and its list
   - enhance the readahead mode for node pages
   - address several cretical deadlock conditions
   - reduce lock_page calls

  The other minor bug fixes and enhancements are as follows.
   - calculation mistakes: overflow
   - bio types: READ, READA, and READ_SYNC
   - fix the recovery flow, data races, and null pointer errors"

* tag 'f2fs-for-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (68 commits)
  f2fs: cover free_nid management with spin_lock
  f2fs: optimize scan_nat_page()
  f2fs: code cleanup for scan_nat_page() and build_free_nids()
  f2fs: bugfix for alloc_nid_failed()
  f2fs: recover when journal contains deleted files
  f2fs: continue to mount after failing recovery
  f2fs: avoid deadlock during evict after f2fs_gc
  f2fs: modify the number of issued pages to merge IOs
  f2fs: remove useless #include <linux/proc_fs.h> as we're now using sysfs as debug entry.
  f2fs: fix inconsistent using of NM_WOUT_THRESHOLD
  f2fs: check truncation of mapping after lock_page
  f2fs: enhance alloc_nid and build_free_nids flows
  f2fs: add a tracepoint on f2fs_new_inode
  f2fs: check nid == 0 in add_free_nid
  f2fs: add REQ_META about metadata requests for submit
  f2fs: give a chance to merge IOs by IO scheduler
  f2fs: avoid frequent background GC
  f2fs: add tracepoints to debug checkpoint request
  f2fs: add tracepoints for write page operations
  f2fs: add tracepoints to debug the block allocation
  ...

Merge tag 'for-f2fs-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "This patch-set includes the following major enhancement patches:
   - remount_fs callback function
   - restore parent inode number to enhance the fsync performance
   - xattr security labels
   - reduce the number of redundant lock/unlock data pages
   - avoid frequent write_inode calls

  The other minor bug fixes are as follows.
   - endian conversion bugs
   - various bugs in the roll-forward recovery routine"

* tag 'for-f2fs-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (56 commits)
  f2fs: fix to recover i_size from roll-forward
  f2fs: remove the unused argument "sbi" of func destroy_fsync_dnodes()
  f2fs: remove reusing any prefree segments
  f2fs: code cleanup and simplify in func {find/add}_gc_inode
  f2fs: optimize the init_dirty_segmap function
  f2fs: fix an endian conversion bug detected by sparse
  f2fs: fix crc endian conversion
  f2fs: add remount_fs callback support
  f2fs: recover wrong pino after checkpoint during fsync
  f2fs: optimize do_write_data_page()
  f2fs: make locate_dirty_segment() as static
  f2fs: remove unnecessary parameter "offset" from __add_sum_entry()
  f2fs: avoid freqeunt write_inode calls
  f2fs: optimise the truncate_data_blocks_range() range
  f2fs: use the F2FS specific flags in f2fs_ioctl()
  f2fs: sync dir->i_size with its block allocation
  f2fs: fix i_blocks translation on various types of files
  f2fs: set sb->s_fs_info before calling parse_options()
  f2fs: support xattr security labels
  f2fs: fix iget/iput of dir during recovery
  ...

Merge tag 'for-f2fs-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "This patch-set includes the following major enhancement patches:
   - support inline xattrs
   - add sysfs support to control GCs explicitly
   - add proc entry to show the current segment usage information
   - improve the GC/SSR performance

  The other bug fixes are as follows:
   - avoid the overflow on status calculation
   - fix some error handling routines
   - fix inconsistent xattr states after power-off-recovery
   - fix incorrect xattr node offset definition
   - fix deadlock condition in fsync
   - fix the fdatasync routine for power-off-recovery"

* tag 'for-f2fs-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (40 commits)
  f2fs: optimize gc for better performance
  f2fs: merge more bios of node block writes
  f2fs: avoid an overflow during utilization calculation
  f2fs: trigger GC when there are prefree segments
  f2fs: use strncasecmp() simplify the string comparison
  f2fs: fix omitting to update inode page
  f2fs: support the inline xattrs
  f2fs: add the truncate_xattr_node function
  f2fs: introduce __find_xattr for readability
  f2fs: reserve the xattr space dynamically
  f2fs: add flags for inline xattrs
  f2fs: fix error return code in init_f2fs_fs()
  f2fs: fix wrong BUG_ON condition
  f2fs: fix memory leak when init f2fs filesystem fail
  f2fs: fix a compound statement label error
  f2fs: avoid writing inode redundantly when creating a file
  f2fs: alloc_page() doesn't return an ERR_PTR
  f2fs: should cover i_xattr_nid with its xattr node page lock
  f2fs: check the free space first in new_node_page
  f2fs: clean up the needless end 'return' of void function
  ...

Merge tag 'for-f2fs-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "This patch-set includes the following major enhancement patches.
   - add a sysfs to control reclaiming free segments
   - enhance the f2fs global lock procedures
   - enhance the victim selection flow
   - wait for selected node blocks during fsync
   - add some tracepoints
   - add a config to remove abundant BUG_ONs

  The other bug fixes are as follows.
   - fix deadlock on acl operations
   - fix some bugs with respect to orphan inodes

  And, there are a bunch of cleanups"

* tag 'for-f2fs-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (42 commits)
  f2fs: issue more large discard command
  f2fs: fix memory leak after kobject init failed in fill_super
  f2fs: cleanup waiting routine for writeback pages in cp
  f2fs: avoid to use a NULL point in destroy_segment_manager
  f2fs: remove unnecessary TestClearPageError when wait pages writeback
  f2fs: update f2fs document
  f2fs: avoid to wait all the node blocks during fsync
  f2fs: check all ones or zeros bitmap with bitops for better mount performance
  f2fs: change the method of calculating the number summary blocks
  f2fs: fix calculating incorrect free size when update xattr in __f2fs_setxattr
  f2fs: add an option to avoid unnecessary BUG_ONs
  f2fs: introduce CONFIG_F2FS_CHECK_FS for BUG_ON control
  f2fs: fix a deadlock during init_acl procedure
  f2fs: clean up acl flow for better readability
  f2fs: remove unnecessary segment bitmap updates
  f2fs: add tracepoint for vm_page_mkwrite
  f2fs: add tracepoint for set_page_dirty
  f2fs: remove redundant set_page_dirty from write_compacted_summaries
  f2fs: add reclaiming control by sysfs
  f2fs: introduce f2fs_balance_fs_bg for some background jobs
  ...

Change-Id: Ied5488471d49d64ce6abb4be19237c4e90829ff6

Conflicts:
	Documentation/ABI/testing/sysfs-fs-f2fs
	Documentation/filesystems/f2fs.txt
	MAINTAINERS
	include/linux/f2fs_fs.h
	include/trace/events/f2fs.h
F2FS: Backport to 3.4

Based off of patches here:
nowcomputing/f2fs-backports#1

Change-Id: I2be6d8abf4e3e4c6b9e8d635700930af432fe37a
f2fs: Update to version in 3.14

f2fs: introduce __find_rev_next(_zero)_bit

When f2fs_set_bit is used, in a byte MSB and LSB is reversed,
in that case we can use __find_rev_next_bit or __find_rev_next_zero_bit.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: change the function names]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: improve searching speed of __next_free_blkoff

To find a zero bit using the result of OR operation between ckpt_valid_map
and cur_valid_map is more fast than find a zero bit in each bitmap.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: adjust changed function name]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a slab cache entry for small discards

This patch adds a slab cache entry for small discards.

Each entry consists of:

struct discard_entry {
	struct list_head list;	/* list head */
	block_t blkaddr;	/* block address to be discarded */
	int len;		/* # of consecutive blocks of the discard */
};

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add key functions for small discards

This patch adds key functions to activate the small discard feature.

Note that this procedure is conducted during the checkpoint only.

In flush_sit_entries(), when a new dirty sit entry is flushed, f2fs calls
add_discard_addrs() which searches candidates to be discarded.
The candidates should be marked *invalidated* and also previous checkpoint
recognizes it as *valid*.

At the end of a checkpoint procedure, f2fs throws discards based on the
discard entry list.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a sysfs entry to control max_discards

If frequent small discards are issued to the device, the performance would
be degraded significantly.
So, this patch adds a sysfs entry to control the number of discards to be
issued during a checkpoint procedure.

By default, f2fs does not issue any small discards, which means max_discards
is zero.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: introduce f2fs_issue_discard() to clean up

Change log from v1:
 o fix 32bit drops reported by Dan Carpenter

This patch adds f2fs_issue_discard() to clean up blkdev_issue_discard() flows.

Dan carpenter reported:
"block_t is a 32 bit type and sector_t is a 64 bit type.  The upper 32
bits of the sector_t are not used because the shift will wrap."

Bug-Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a tracepoint for f2fs_issue_discard

This patch adds a tracepoint for f2fs_issue_discard.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: use f2fs_put_page to release page for uniform style

We should use f2fs_put_page to release page for uniform style of f2fs code.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: clean up the do_submit_bio flow

This patch introduces PAGE_TYPE_OF_BIO() and cleans up do_submit_bio() with it.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: use sbi->write_mutex for write bios

This patch removes an unnecessary semaphore (i.e., sbi->bio_sem).
There is no reason to use the semaphore when f2fs submits read and write IOs.
Instead, let's use a write mutex and cover the sbi->bio[] by the lock.

Change log from v1:
 o split write_mutex suggested by Chao Yu

Chao described,
"All DATA/NODE/META bio buffers in superblock is protected by
'sbi->write_mutex', but each bio buffer area is independent, So we
should split write_mutex to three for DATA/NODE/META."

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: disable the extent cache ops on high fragmented files

The f2fs manages an extent cache to search a number of consecutive data blocks
very quickly.

However it conducts unnecessary cache operations if the file is highly
fragmented with no valid extent cache.

In such the case, we don't need to handle the extent cache, but just can disable
the cache facility.

Nevertheless, this patch gives one more chance to enable the extent cache.

For example,
1. create a file
2. write data sequentially which produces a large valid extent cache
3. update some data, resulting in a fragmented extent
4. if the fragmented extent is too small, then drop extent cache
5. close the file

6. open the file again
7. give another chance to make a new extent cache
8. write data sequentially again which creates another big extent cache.
...

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: introduce a bio array for per-page write bios

The f2fs has three bio types, NODE, DATA, and META, and manages some data
structures per each bio types.

The codes are a little bit messy, thus, this patch introduces a bio array
which groups individual data structures as follows.

struct f2fs_bio_info {
	struct bio *bio;		/* bios to merge */
	sector_t last_block_in_bio;	/* last block number */
	struct mutex io_mutex;		/* mutex for bio */
};

struct f2fs_sb_info {
	...
	struct f2fs_bio_info write_io[NR_PAGE_TYPE];	/* for write bios */
	...
};

The code changes from this new data structure are trivial.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: convert remove_inode_page to void

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: convert dev_valid_block_count to void

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: convert inc/dec_valid_node_count to inc/dec one count

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: simplify write_orphan_inodes for better readable

Simplify write_orphan_inodes for better readable. Because we hold the
orphan_inode_mutex, so it's safe to use list_for_each_entry instead of
list_for_each_safe.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: move the list_head initialization into the lock protection region

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a new function to support for merging contiguous read

For better read performance, we add a new function to support for merging
contiguous read as the one for write.

v1-->v2:
 o add declarations here as Gu Zheng suggested.
 o use new structure f2fs_bio_info introduced by Jaegeuk Kim.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>

f2fs: merge read IOs at ra_nat_pages()

Change log from v1:
  o add mark_page_accessed() not to reclaim the nat pages.

This patch changes the policy of submitting read bios at ra_nat_pages.

Previously, f2fs submits small read bios with block plugging.
But, with this patch, f2fs itself merges read bios first and then submits a
large bio, which can reduce the bio handling overheads.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: simplify IS_DATASEG and IS_NODESEG macro

It is not efficient comparing each segment type to find node or data.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: remove unnecessary white spaces]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: adds a tracepoint for submit_read_page

This patch adds a tracepoint for submit_read_page.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: integrate tracepoints of f2fs_submit_read(_write)_page]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: adds a tracepoint for f2fs_submit_read_bio

This patch adds a tracepoint for f2fs_submit_read_bio.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: integrate tracepoints of f2fs_submit_read(_write)_bio]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: read contiguous sit entry pages by merging for mount performance

Previously we read sit entries page one by one, this method lost the chance
of reading contiguous page together. So we read pages as contiguous as
possible for better mount performance.

change log:
 o merge judgements/use 'Continue' or 'Break' instead of 'Goto' as Gu Zheng
   suggested.
 o add mark_page_accessed() before release page to delay VM reclaiming.
 o remove '*order' for simplification of function as Jaegeuk Kim suggested.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: fix a bug on the block address calculation]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid lock debugging overhead

If CONFIG_F2FS_CHECK_FS is unset, we don't need to add any debugging overhead.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a new function: f2fs_reserve_block()

Add the function f2fs_reserve_block() to easily reserve new blocks, and
use it to clean up more codes.

Signed-off-by: Huajun Li <huajun.li@intel.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Weihong Xu <weihong.xu@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add detailed information of bio types in the tracepoints

This patch inserts information of bio types in more detail.
So, we can now see REQ_META and REQ_PRIO too.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: send REQ_META or REQ_PRIO when reading meta area

Let's send REQ_META or REQ_PRIO when reading meta area such as NAT/SIT
etc.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add flags and helpers to support inline data

Add new inode flags F2FS_INLINE_DATA and FI_INLINE_DATA to indicate
whether the inode has inline data.

Inline data makes use of inode block's data indices region to save small
file. Currently there are 923 data indices in an inode block. Since
inline xattr has made use of the last 50 indices to save its data, there
are 873 indices left which can be used for inline data. When
FI_INLINE_DATA is set, the layout of inode block's indices region is
like below:

+-----------------+
|                 | Reserved. reserve_new_block() will make use of
| i_addr[0]       | i_addr[0] when we need to reserve a new data block
|                 | to convert inline data into regular one's.
|-----------------|
|                 | Used by inline data. A file whose size is less than
| i_addr[1~872]   | 3488 bytes(~3.4k) and doesn't reserve extra
|                 | blocks by fallocate() can be saved here.
|-----------------|
|                 |
| i_addr[873~922] | Reserved for inline xattr
|                 |
+-----------------+

Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Huajun Li <huajun.li@intel.com>
Signed-off-by: Weihong Xu <weihong.xu@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a new mount option: inline_data

Add a mount option: inline_data. If the mount option is set,
data of New created small files can be stored in their inode.

Signed-off-by: Huajun Li <huajun.li@intel.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Weihong Xu <weihong.xu@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove unnecessary return value

Let's remove the unnecessary return value.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: fix a potential out of range issue

Fix a potential out of range issue introduced by commit:
22fb72225a
f2fs: simplify write_orphan_inodes for better readable

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: bug fix on bit overflow from 32bits to 64bits

This patch fixes some bit overflows by the shift operations.

Dan Carpenter reported potential bugs on bit overflows as follows.

fs/f2fs/segment.c:910 submit_write_page()
	warn: should 'blk_addr << ((sbi)->log_blocksize - 9)' be a 64 bit type?
fs/f2fs/checkpoint.c:429 get_valid_checkpoint()
	warn: should '1 << ()' be a 64 bit type?
fs/f2fs/data.c:408 f2fs_readpage()
	warn: should 'blk_addr << ((sbi)->log_blocksize - 9)' be a 64 bit type?
fs/f2fs/data.c:457 submit_read_page()
	warn: should 'blk_addr << ((sbi)->log_blocksize - 9)' be a 64 bit type?
fs/f2fs/data.c:525 get_data_block_ro()
	warn: should 'i << blkbits' be a 64 bit type?

Bug-Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove unnecessary condition checks

This patch removes the unnecessary condition checks on:

fs/f2fs/gc.c:667 do_garbage_collect() warn: 'sum_page' isn't an ERR_PTR
fs/f2fs/f2fs.h:795 f2fs_put_page() warn: 'page' isn't an ERR_PTR

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove unneeded code in punch_hole

Because FALLOC_FL_PUNCH_HOLE flag must be ORed with FALLOC_FL_KEEP_SIZE
in fallocate, so we could remove the useless 'keep size' branch code which
will never be excuted in punch_hole.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Fan Li <fanofcode.li@samsung.com>
[Jaegeuk Kim: remove an unnecessary parameter togather]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid to calculate incorrect max orphan number

Because we will write node summaries when do_checkpoint with umount flag,
our number of max orphan blocks should minus NR_CURSEG_NODE_TYPE additional.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Shu Tan <shu.tan@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: correct type of wait in struct bio_private

The void *wait in bio_private is used for waiting completion of checkpoint bio.
So we don't need to use its type as void, but declare it as completion type.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: add description]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: use true and false for boolean variable

The inode_page_locked should be a boolean variable.

struct dnode_of_data {
	struct inode *inode;            /* vfs inode pointer */
	struct page *inode_page;        /* its inode page, NULL is possible */
	struct page *node_page;         /* cached direct node page */
	nid_t nid;                      /* node id of the direct node block */
	unsigned int ofs_in_node;       /* data offset in the node page */
==>	bool inode_page_locked;         /* inode page is locked or not */
	block_t data_blkaddr;           /* block address of the node block */
};

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: add description]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: check return value of f2fs_readpage in find_data_page

We should return error if we do not get an updated page in find_date_page
when f2fs_readpage failed.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: convert recover_orphan_inodes to void

The recover_orphan_inodes() returns no error all the time, so we don't need to
check its errors.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: add description]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove the own bi_private allocation

Previously f2fs allocates its own bi_private data structure all the time even
though we don't use it. But, can we remove this bi_private allocation?

This patch removes such the additional bi_private allocation.

1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
 - This removes the usecases of bi_private in end_io.

2. Use bi_private only when we really need it.
 - The bi_private is used only when the checkpoint procedure is conducted.
 - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait its bio
completion.
 - Since we have no dependancies to remove bi_private now, let's just use
 bi_private pointer as the completion pointer.

Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: refactor bio-related operations

This patch integrates redundant bio operations on read and write IOs.

1. Move bio-related codes to the top of data.c.
2. Replace f2fs_submit_bio with f2fs_submit_merged_bio, which handles read
   bios additionally.
3. Introduce __submit_merged_bio to submit the merged bio.
4. Change f2fs_readpage to f2fs_submit_page_bio.
5. Introduce f2fs_submit_page_mbio to integrate previous submit_read_page and
   submit_write_page.

Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com >
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: readahead contiguous pages for restore_node_summary

If cp has no CP_UMOUNT_FLAG, we will read all pages in whole node segment
one by one, it makes low performance. So let's merge contiguous pages and
readahead for better performance.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: adjust the new bio operations]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove debufs dir if debugfs_create_file() failed

When debugfs_create_file() failed in f2fs_create_root_stats(),
debugfs_root should be remove.

Signed-off-by: Younger Liu <liuyiyang@hisense.com>
Cc: Younger Liu <younger.liucn@gmail.com>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: replace the debugfs_root with f2fs_debugfs_root

This minor change for the naming conventions of debugfs_root
to avoid any possible conflicts to the other filesystem.

Signed-off-by: Younger Liu <younger.liucn@gmail.com>
Cc: Younger Liu <younger.liucn@gmail.com>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
[Jaegeuk Kim: change the patch name]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: use inner macro GFP_F2FS_ZERO for simplification

Use inner macro GFP_F2FS_ZERO to instead of GFP_NOFS | __GFP_ZERO for
simplification of code.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid unneeded page release for correct _count of page

In find_fsync_dnodes() and recover_data(), our flow is like this:

->f2fs_submit_page_bio()
	-> f2fs_put_page()
		-> page_cache_release()	---- page->_count declined to zero.
->__free_pages()
	-> put_page_testzero() ---- page->_count will be declined again.

We will get a segment fault in put_page_testzero when CONFIG_DEBUG_VM
is on, or return MM with a bad page with wrong _count num.

So let's just release this page.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add unlikely() macro for compiler optimization

As we know, some of our branch condition will rarely be true. So we could add
'unlikely' to let compiler optimize these code, by this way we could drop
unneeded 'jump' assemble code to improve performance.

change log:
 o add *unlikely* as many as possible across the whole source files at once
   suggested by Jaegeuk Kim.

Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add unlikely() macro for compiler more aggressively

This patch adds unlikely() macro into the most of codes.
The basic rule is to add that when:
- checking unusual errors,
- checking page mappings,
- and the other unlikely conditions.

Change log from v1:
 - Don't add unlikely for the NULL test and error test: advised by Andi Kleen.

Cc: Chao Yu <chao2.yu@samsung.com>
Cc: Andi Kleen <andi@firstfloor.org>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: merge pages with the same sync_mode flag

Previously f2fs submits most of write requests using WRITE_SYNC, but f2fs_write_data_pages
submits last write requests by sync_mode flags callers pass.

This causes a performance problem since continuous pages with different sync flags
can't be merged in cfq IO scheduler(thanks yu chao for pointing it out), and synchronous
requests often take more time.

This patch makes the following modifies to DATA writebacks:

1. every page will be written back using the sync mode caller pass.
2. only pages with the same sync mode can be merged in one bio request.

These changes are restricted to DATA pages.Other types of writebacks are modified
To remain synchronous.

In my test with tiotest, f2fs sequence write performance is improved by about 7%-10% ,
and this patch has no obvious impact on other performance tests.

Signed-off-by: Fan Li <fanofcode.li@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: refactor bio->rw handling

This patch introduces f2fs_io_info to mitigate the complex parameter list.

struct f2fs_io_info {
	enum page_type type;		/* contains DATA/NODE/META/META_FLUSH */
	int rw;				/* contains R/RS/W/WS */
	int rw_flag;			/* contains REQ_META/REQ_PRIO */
}

1. f2fs_write_data_pages
 - DATA
 - WRITE_SYNC is set when wbc->WB_SYNC_ALL.

2. sync_node_pages
 - NODE
 - WRITE_SYNC all the time

3. sync_meta_pages
 - META
 - WRITE_SYNC all the time
 - REQ_META | REQ_PRIO all the time

 ** f2fs_submit_merged_bio() handles META_FLUSH.

4. ra_nat_pages, ra_sit_pages, ra_sum_pages
 - META
 - READ_SYNC

Cc: Fan Li <fanofcode.li@samsung.com>
Cc: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: fix the location of tracepoint

We need to get a trace before submit_bio, since its bi_sector is remapped during
the submit_bio.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: missing kmem_cache_destroy for discard_entry

insmod f2fs.ko is failed after insmod and rmmod firstly.

$ sudo insmod fs/f2fs/f2fs.ko
insmod: error inserting 'fs/f2fs/f2fs.ko': -1 Cannot allocate memory

-- dmesg --
kmem_cache_sanity_check (free_nid): Cache name already exists.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: introduce sysfs entry to control in-place-update policy

This patch introduces new sysfs entries for users to control the policy of
in-place-updates, namely IPU, in f2fs.

Sometimes f2fs suffers from performance degradation due to its out-of-place
update policy that produces many additional node block writes.
If the storage performance is very dependant on the amount of data writes
instead of IO patterns, we'd better drop this out-of-place update policy.

This patch suggests 5 polcies and their triggering conditions as follows.

[sysfs entry name = ipu_policy]

0: F2FS_IPU_FORCE       all the time,
1: F2FS_IPU_SSR         if SSR mode is activated,
2: F2FS_IPU_UTIL        if FS utilization is over threashold,
3: F2FS_IPU_SSR_UTIL    if SSR mode is activated and FS utilization is over
                        threashold,
4: F2FS_IPU_DISABLE    disable IPU. (=default option)

[sysfs entry name = min_ipu_util]

This parameter controls the threshold to trigger in-place-updates.
The number indicates percentage of the filesystem utilization, and used by
F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.

For more details, see need_inplace_update() in segment.h.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: introduce a new direct_IO write path

Previously, f2fs doesn't support direct IOs with high performance, which throws
every write requests via the buffered write path, resulting in highly
performance degradation due to memory opeations like copy_from_user.

This patch introduces a new direct IO path in which every write requests are
processed by generic blockdev_direct_IO() with enhanced get_block function.

The get_data_block() in f2fs handles:
1. if original data blocks are allocates, then give them to blockdev.
2. otherwise,
  a. preallocate requested block addresses
  b. do not use extent cache for better performance
  c. give the block addresses to blockdev

This policy induces that:
- new allocated data are sequentially written to the disk
- updated data are randomly written to the disk.
- f2fs gives consistency on its file meta, not file data.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: write dirty meta pages collectively

This patch enhances writing dirty meta pages collectively in background.
During the file data writes, it'd better avoid to write small dirty meta pages
frequently.
So let's give a chance to collect a number of dirty meta pages for a while.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: move all the bio initialization into __bio_alloc

Move all the bio initialization into __bio_alloc, and some minor cleanups are
also added.

v3:
  Use 'bool' rather than 'int' as Kim suggested.

v2:
  Use 'is_read' rather than 'rw' as Yu Chao suggested.
  Remove the needless initialization of bio->bi_private.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove the rw_flag domain from f2fs_io_info

When using the f2fs_io_info in the low level, we still need to merge the
rw and rw_flag, so use the rw to hold all the io flags directly,
and remove the rw_flag field.

ps.It is based on the previous patch:
f2fs: move all the bio initialization into __bio_alloc

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: update several comments

Update several comments:
1. use f2fs_{un}lock_op install of mutex_{un}lock_op.
2. update comment of get_data_block().
3. update description of node offset.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid to set wrong pino of inode when rename dir

When we rename a dir to new name which is not exist previous,
we will set pino of parent inode with ino of child inode in f2fs_set_link.
It destroy consistency of pino, it should be fixed.

Thanks for previous work of Shu Tan.

Signed-off-by: Shu Tan <shu.tan@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: check filename length in recover_dentry

In current flow, we will get Null return value of f2fs_find_entry in
recover_dentry when name.len is bigger than F2FS_NAME_LEN, and then we
still add this inode into its dir entry.
To avoid this situation, we must check filename length before we use it.

Another point is that we could remove the code of checking filename length
In f2fs_find_entry, because f2fs_lookup will be called previously to ensure of
validity of filename length.

V2:
 o add WARN_ON() as Jaegeuk Kim suggested.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: introduce F2FS_INODE macro to get f2fs_inode

This patch introduces F2FS_INODE that returns struct f2fs_inode * from the inode
page.
By using this macro, we can remove unnecessary casting codes like below.

   struct f2fs_inode *ri = &F2FS_NODE(inode_page)->i;
-> struct f2fs_inode *ri = F2FS_INODE(inode_page);

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: should put the dnode when NEW_ADDR is detected

When get_dnode_of_data() in get_data_block() returns a successful dnode, we
should put the dnode.
But, previously, if its data block address is equal to NEW_ADDR, we didn't do
that, resulting in a deadlock condition.
So, this patch splits original error conditions with this case, and then calls
f2fs_put_dnode before finishing the function.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: check the blocksize before calling generic_direct_IO path

The f2fs supports 4KB block size. If user requests dwrite with under 4KB data,
it allocates a new 4KB data block.
However, f2fs doesn't add zero data into the untouched data area inside the
newly allocated data block.

This incurs an error during the xfstest #263 test as follow.

263 12s ... [failed, exit status 1] - output mismatch (see 263.out.bad)
	--- 263.out	2013-03-09 03:37:15.043967603 +0900
	+++ 263.out.bad	2013-12-27 04:20:39.230203114 +0900
	@@ -1,3 +1,976 @@
	QA output created by 263
	fsx -N 10000 -o 8192 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z
	-fsx -N 10000 -o 128000 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z
	+fsx -N 10000 -o 8192 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z
	+truncating to largest ever: 0x12a00
	+truncating to largest ever: 0x75400
	+fallocating to largest ever: 0x79cbf
	...
	(Run 'diff -u 263.out 263.out.bad' to see the entire diff)
	Ran: 263
	Failures: 263
	Failed 1 of 1 tests

It turns out that, when the test tries to write 2KB data with dio, the new dio
path allocates 4KB data block without filling zero data inside the remained 2KB
area. Finally, the output file contains a garbage data for that region.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: convert max_orphans to a field of f2fs_sb_info

Previously, we need to calculate the max orphan num when we try to acquire an
orphan inode, but it's a stable value since the super block was inited. So
converting it to a field of f2fs_sb_info and use it directly when needed seems
a better choose.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: key functions to handle inline data

Functions to implement inline data read/write, and move inline data to
normal data block when file size exceeds inline data limitation.

Signed-off-by: Huajun Li <huajun.li@intel.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Weihong Xu <weihong.xu@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: handle inline data operations

Hook inline data read/write, truncate, fallocate, setattr, etc.

Files need meet following 2 requirement to inline:
 1) file size is not greater than MAX_INLINE_DATA;
 2) file doesn't pre-allocate data blocks by fallocate().

FI_INLINE_DATA will not be set while creating a new regular inode because
most of the files are bigger than ~3.4K. Set FI_INLINE_DATA only when
data is submitted to block layer, ranther than set it while creating a new
inode, this also avoids converting data from inline to normal data block
and vice versa.

While writting inline data to inode block, the first data block should be
released if the file has a block indexed by i_addr[0].

On the other hand, when a file operation is appied to a file with inline
data, we need to test if this file can remain inline by doing this
operation, otherwise it should be convert into normal file by reserving
a new data block, copying inline data to this new block and clear
FI_INLINE_DATA flag. Because reserve a new data block here will make use
of i_addr[0], if we save inline data in i_addr[0..872], then the first
4 bytes would be overwriten. This problem can be avoided simply by
not using i_addr[0] for inline data.

Signed-off-by: Huajun Li <huajun.li@intel.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Weihong Xu <weihong.xu@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: don't need to get f2fs_lock_op for the inline_data test

This patch locates checking the inline_data prior to calling f2fs_lock_op()
in truncate_blocks(), since getting the lock is unnecessary.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: convert inline_data for punch_hole

In the punch_hole(), let's convert inline_data all the time for simplicity and
to avoid potential deadlock conditions.
It is pretty much not a big deal to do this.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: call f2fs_put_page at the error case

In f2fs_write_begin(), if f2fs_conver_inline_data() returns an error like
-ENOSPC, f2fs should call f2fs_put_page().
Otherwise, it is remained as a locked page, resulting in the following bug.

[<ffffffff8114657e>] sleep_on_page+0xe/0x20
[<ffffffff81146567>] __lock_page+0x67/0x70
[<ffffffff81157d08>] truncate_inode_pages_range+0x368/0x5d0
[<ffffffff81157ff5>] truncate_inode_pages+0x15/0x20
[<ffffffff8115804b>] truncate_pagecache+0x4b/0x70
[<ffffffff81158082>] truncate_setsize+0x12/0x20
[<ffffffffa02a1842>] f2fs_setattr+0x72/0x270 [f2fs]
[<ffffffff811cdae3>] notify_change+0x213/0x400
[<ffffffff811ab376>] do_truncate+0x66/0xa0
[<ffffffff811ab541>] vfs_truncate+0x191/0x1b0
[<ffffffff811ab5bc>] do_sys_truncate+0x5c/0xa0
[<ffffffff811ab78e>] SyS_truncate+0xe/0x10
[<ffffffff81756052>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: refactor f2fs_convert_inline_data

Change log from v1:
 o handle NULL pointer of grab_cache_page_write_begin() pointed by Chao Yu.

This patch refactors f2fs_convert_inline_data to check a couple of conditions
internally for deciding whether it needs to convert inline_data or not.

So, the new f2fs_convert_inline_data initially checks:
1) f2fs_has_inline_data(), and
2) the data size to be changed.

If the inode has inline_data but the size to fill is less than MAX_INLINE_DATA,
then we don't need to convert the inline_data with data allocation.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add the number of inline_data files to status info

This patch adds the number of inline_data files into the status information.
Note that the number is reset whenever the filesystem is newly mounted.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add inline_data recovery routine

This patch adds a inline_data recovery routine with the following policy.

[prev.] [next] of inline_data flag
   o       o  -> recover inline_data
   o       x  -> remove inline_data, and then recover data blocks
   x       o  -> remove inline_data, and then recover inline_data
   x       x  -> recover data blocks

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: handle errors correctly during f2fs_reserve_block

The get_dnode_of_data nullifies inode and node page when error is occurred.

There are two cases that passes inode page into get_dnode_of_data().

1. make_empty_dir()
    -> get_new_data_page()
      -> f2fs_reserve_block(ipage)
	-> get_dnode_of_data()

2. f2fs_convert_inline_data()
    -> __f2fs_convert_inline_data()
      -> f2fs_reserve_block(ipage)
	-> get_dnode_of_data()

This patch adds correct error handling codes when get_dnode_of_data() returns
an error.

At first, f2fs_reserve_block() calls f2fs_put_dnode() whenever reserve_new_block
returns an error.
So, the rule of f2fs_reserve_block() is to nullify inode page when there is any
error internally.

Finally, two callers of f2fs_reserve_block() should call f2fs_put_dnode()
appropriately if they got an error since successful f2fs_reserve_block().

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: fix truncate_partial_nodes bug

The truncate_partial_nodes puts pages incorrectly in the following two cases.
Note that the value for argc 'depth' can only be 2 or 3.
Please see truncate_inode_blocks() and truncate_partial_nodes().

1) An err is occurred in the first 'for' loop
  When err is occurred with depth = 2, pages[0] is invalid, so this page doesn't
  need to be put. There is no problem, however, when depth is 3, it doesn't put
  the pages correctly where pages[0] is valid and pages[1] is invalid.
  In this case, depth is set to 2 (ref to statemnt depth = i + 1), and then
  'goto fail'.
  In label 'fail', for (i = depth - 3; i >= 0; i--) cannot meet the condition
  because i = -1, so pages[0] cann't be put.

2) An err happened in the second 'for' loop
  Now we've got pages[0] with depth = 2, or we've got pages[0] and pages[1]
  with depth = 3. When an err is detected, we need 'goto fail' to put such
  the pages.
  When depth is 2, in label 'fail', for (i = depth - 3; i >= 0; i--) cann't
  meet the condition because i = -1, so pages[0] cann't be put.
  When depth is 3, in label 'fail', for (i = depth - 3; i >= 0; i--) can
  only put pages[0], pages[1] also cann't be put.

Note that 'depth' has been changed before first 'goto fail' (ref to statemnt
depth = i + 1), so passing this modified 'depth' to the tracepoint,
trace_f2fs_truncate_partial_nodes, is also incorrect.

Signed-off-by: Shifei Ge <shifei10.ge@samsung.com>
[Jaegeuk Kim: modify the description and fix one bug]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid to left uninitialized data in page when read inline data

Change log from v1:
 o reduce unneeded memset in __f2fs_convert_inline_data

>From 58796be2bd2becbe8d52305210fb2a64e7dd80b6 Mon Sep 17 00:00:00 2001
From: Chao Yu <chao2.yu@samsung.com>
Date: Mon, 30 Dec 2013 09:21:33 +0800
Subject: [PATCH] f2fs: avoid to left uninitialized data in page when read
 inline data

We left uninitialized data in the tail of page when we read an inline data
page. So let's initialize left part of the page excluding inline data region.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid to read inline data except first page

Here is a case which could read inline page data not from first page.

1. write inline data
2. lseek to offset 4096
3. read 4096 bytes from offset 4096
	(read_inline_data read inline data page to non-first page,
	And previously VFS has add this page to page cache)
4. ftruncate offset 8192
5. read 4096 bytes from offset 4096
	(we meet this updated page with inline data in cache)

So we should leave this page with inited data and uptodate flag
for this case.

Change log from v1:
 o fix a deadlock bug

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: improve write performance under frequent fsync calls

When considering a bunch of data writes with very frequent fsync calls, we
are able to think the following performance regression.

N: Node IO, D: Data IO, IO scheduler: cfq

Issue    pending IOs
	 D1 D2 D3 D4
 D1         D2 D3 D4 N1
 D2            D3 D4 N1 N2
 N1            D3 D4 N2 D1
 --> N1 can be selected by cfq becase of the same priority of N and D.
     Then D3 and D4 would be delayed, resuling in performance degradation.

So, when processing the fsync call, it'd better give higher priority to data IOs
than node IOs by assigning WRITE and WRITE_SYNC respectively.
This patch improves the random wirte performance with frequent fsync calls by up
to 10%.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add a sysfs entry to control max_victim_search

Previously during SSR and GC, the maximum number of retrials to find a victim
segment was hard-coded by MAX_VICTIM_SEARCH, 4096 by default.

This number makes an effect on IO locality, when SSR mode is activated, which
results in performance fluctuation on some low-end devices.

If max_victim_search = 4, the victim will be searched like below.
("D" represents a dirty segment, and "*" indicates a selected victim segment.)

 D1 D2 D3 D4 D5 D6 D7 D8 D9
[   *       ]
      [   *    ]
            [         * ]
	                [ ....]

This patch adds a sysfs entry to control the number dynamically through:
  /sys/fs/f2fs/$dev/max_victim_search

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove the needless parameter of f2fs_wait_on_page_writeback

"boo sync" parameter is never referenced in f2fs_wait_on_page_writeback.
We should remove this parameter.

Signed-off-by: Yuan Zhong <yuan.mark.zhong@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: move grabing orphan pages out of protection region

Move grabing orphan block page out of protection region, and grab all
the orphan block pages ahead.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: remove unnecessary code pointed by Chao Yu]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: move alloc new orphan node out of lock protection region

Move alloc new orphan node out of lock protection region.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: use spinlock rather than mutex for better speed

With the 2 previous changes, all the long time operations are moved out
of the protection region, so here we can use spinlock rather than mutex
(orphan_inode_mutex) for lower overhead.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add delimiter to seperate name and value in debug phrase

Support for f2fs-tools/tools/f2stat to monitor
/sys/kernel/debug/f2fs/status

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: avoid f2fs_balance_fs call during pageout

This patch should resolve the following bug.

=========================================================
[ INFO: possible irq lock inversion dependency detected ]
3.13.0-rc5.f2fs+ #6 Not tainted
---------------------------------------------------------
kswapd0/41 just changed the state of lock:
 (&sbi->gc_mutex){+.+.-.}, at: [<ffffffffa030503e>] f2fs_balance_fs+0xae/0xd0 [f2fs]
but this lock took another, RECLAIM_FS-READ-unsafe lock in the past:
 (&sbi->cp_rwsem){++++.?}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
Chain exists of:
  &sbi->gc_mutex --> &sbi->cp_mutex --> &sbi->cp_rwsem

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->cp_rwsem);
                               local_irq_disable();
                               lock(&sbi->gc_mutex);
                               lock(&sbi->cp_mutex);
  <Interrupt>
    lock(&sbi->gc_mutex);

 *** DEADLOCK ***

This bug is due to the f2fs_balance_fs call in f2fs_write_data_page.
If f2fs_write_data_page is triggered by wbc->for_reclaim via kswapd, it should
not call f2fs_balance_fs which tries to get a mutex grabbed by original syscall
flow.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: missing REQ_META and REQ_PRIO when sync_meta_pages(META_FLUSH)

Doing sync_meta_pages with META_FLUSH when checkpoint, we overide rw
using WRITE_FLUSH_FUA. At this time, we also should set
REQ_META|REQ_PRIO.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: clean checkpatch warnings

Fixed a variety of trivial checkpatch warnings.  The only delta should
be some minor formatting on log strings that were split / too long.

Signed-off-by: Chris Fries <cfries@motorola.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: call mark_inode_dirty to flush dirty pages

If a dentry page is updated, we should call mark_inode_dirty to add the inode
into the dirty list, so that its dentry pages are flushed to the disk.
Otherwise, the inode can be evicted without flush.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: move a branch for code redability

This patch moves a function in f2fs_delete_entry for code readability.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: add help function META_MAPPING

Introduce help function META_MAPPING() to get the cache meta blocks'
address space.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: remove the orphan block page array

As the orphan_blocks may be max to 504, so it is not security
and rigorous to store such a large array in the kernel stack
as Dan Carpenter said.
In fact, grab_meta_page has locked the page in the page cache,
and we can use find_get_page() to fetch the page safely in the
downstream, so we can remove the page array directly.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: introduce NODE_MAPPING for code consistency

This patch adds NODE_MAPPING which is similar as META_MAPPING introduced by
Gu Zheng.

Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs: drop obsolete node page when it is truncated

If a node page is trucated, we'd better drop the page in the node_inode's page
cache for better memory footprint.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

Change-Id: I1b7c3378b7f7adb13477376164e91ab080b50d8b