1. 22 Jan, 2014 3 commits
  2. 20 Jan, 2014 1 commit
  3. 16 Jan, 2014 2 commits
    • Changman Lee's avatar
      f2fs: missing REQ_META and REQ_PRIO when sync_meta_pages(META_FLUSH) · c434cbc0
      Changman Lee authored
      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: default avatarChangman Lee <cm224.lee@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      c434cbc0
    • Jaegeuk Kim's avatar
      f2fs: avoid f2fs_balance_fs call during pageout · c33ec326
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      c33ec326
  4. 14 Jan, 2014 5 commits
  5. 09 Jan, 2014 1 commit
  6. 08 Jan, 2014 2 commits
    • Jaegeuk Kim's avatar
      f2fs: add a sysfs entry to control max_victim_search · b1c57c1c
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      b1c57c1c
    • Jaegeuk Kim's avatar
      f2fs: improve write performance under frequent fsync calls · fb5566da
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      fb5566da
  7. 06 Jan, 2014 9 commits
    • Chao Yu's avatar
      f2fs: avoid to read inline data except first page · 04a17fb1
      Chao Yu authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      04a17fb1
    • Chao Yu's avatar
      f2fs: avoid to left uninitialized data in page when read inline data · 18309aaa
      Chao Yu authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      18309aaa
    • shifei10.ge's avatar
      f2fs: fix truncate_partial_nodes bug · a225dca3
      shifei10.ge authored
      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: default avatarShifei Ge <shifei10.ge@samsung.com>
      [Jaegeuk Kim: modify the description and fix one bug]
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      a225dca3
    • Jaegeuk Kim's avatar
      f2fs: handle errors correctly during f2fs_reserve_block · a8865372
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      a8865372
    • Jaegeuk Kim's avatar
      f2fs: add inline_data recovery routine · 1e1bb4ba
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      1e1bb4ba
    • Jaegeuk Kim's avatar
      f2fs: add the number of inline_data files to status info · 0dbdc2ae
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      0dbdc2ae
    • Jaegeuk Kim's avatar
      f2fs: refactor f2fs_convert_inline_data · 9e09fc85
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      9e09fc85
    • Jaegeuk Kim's avatar
      f2fs: call f2fs_put_page at the error case · 26f466f4
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      26f466f4
    • Jaegeuk Kim's avatar
      f2fs: convert inline_data for punch_hole · 8230a0a4
      Jaegeuk Kim authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      8230a0a4
  8. 27 Dec, 2013 1 commit
  9. 26 Dec, 2013 8 commits
    • Huajun Li's avatar
      f2fs: update f2fs Documentation · e4024e86
      Huajun Li authored
      This patch describes the inline_data support in f2fs document.
      Signed-off-by: default avatarHuajun Li <huajun.li@intel.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      e4024e86
    • Huajun Li's avatar
      f2fs: handle inline data operations · 9ffe0fb5
      Huajun Li authored
      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: default avatarHuajun Li <huajun.li@intel.com>
      Signed-off-by: default avatarHaicheng Li <haicheng.li@linux.intel.com>
      Signed-off-by: default avatarWeihong Xu <weihong.xu@intel.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      9ffe0fb5
    • Huajun Li's avatar
      f2fs: key functions to handle inline data · e18c65b2
      Huajun Li authored
      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: default avatarHuajun Li <huajun.li@intel.com>
      Signed-off-by: default avatarHaicheng Li <haicheng.li@linux.intel.com>
      Signed-off-by: default avatarWeihong Xu <weihong.xu@intel.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      e18c65b2
    • Gu Zheng's avatar
      f2fs: convert max_orphans to a field of f2fs_sb_info · 0d47c1ad
      Gu Zheng authored
      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: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      0d47c1ad
    • Jaegeuk Kim's avatar
      f2fs: check the blocksize before calling generic_direct_IO path · 944fcfc1
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      944fcfc1
    • Jaegeuk Kim's avatar
      f2fs: should put the dnode when NEW_ADDR is detected · 1ec79083
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      1ec79083
    • Jaegeuk Kim's avatar
      f2fs: introduce F2FS_INODE macro to get f2fs_inode · 58bfaf44
      Jaegeuk Kim authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      58bfaf44
    • Chao Yu's avatar
      f2fs: check filename length in recover_dentry · d96b1431
      Chao Yu authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      d96b1431
  10. 23 Dec, 2013 8 commits
    • Chao Yu's avatar
      f2fs: avoid to set wrong pino of inode when rename dir · deead090
      Chao Yu authored
      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: default avatarShu Tan <shu.tan@samsung.com>
      Signed-off-by: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      deead090
    • Chao Yu's avatar
      f2fs: update several comments · 4f4124d0
      Chao Yu authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      4f4124d0
    • Gu Zheng's avatar
      f2fs: remove the rw_flag domain from f2fs_io_info · 7e8f2308
      Gu Zheng authored
      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: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      7e8f2308
    • Gu Zheng's avatar
      f2fs: move all the bio initialization into __bio_alloc · 940a6d34
      Gu Zheng authored
      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: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      940a6d34
    • Jaegeuk Kim's avatar
      f2fs: add description about small_discards in document · ba0697ec
      Jaegeuk Kim authored
      This patch adds a description about small_disacrds in the f2fs document.
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      ba0697ec
    • Jaegeuk Kim's avatar
      f2fs: write dirty meta pages collectively · 5459aa97
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      5459aa97
    • Jaegeuk Kim's avatar
      f2fs: introduce a new direct_IO write path · bfad7c2d
      Jaegeuk Kim authored
      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: default avatarChao Yu <chao2.yu@samsung.com>
      Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      bfad7c2d
    • Jaegeuk Kim's avatar
      f2fs: introduce sysfs entry to control in-place-update policy · 216fbd64
      Jaegeuk Kim authored
      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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
      216fbd64