Commit Graph

252 Commits

Author SHA1 Message Date
Chao Yu
0f34802858 f2fs: support checkpoint error injection
This patch adds to support checkpoint error injection in f2fs for testing
fatal error tolerance, it will be useful that it can simulate abnormal
power off by f2fs itself instead of calling godown ioctl by running apps.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:35 -07:00
Chao Yu
2443b8b363 f2fs: fix to recover old fault injection config in ->remount_fs
In ->remount_fs, we didn't recover original fault injection config if
we encounter error, fix it.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:34 -07:00
Chao Yu
36dbd3287f f2fs: do fault injection initialization in default_options
Do fault injection initialization in default_options to keep consistent
with other default option configurating.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:33 -07:00
Chao Yu
1ecc0c5c50 f2fs: support configuring fault injection per superblock
Previously, we only support global fault injection configuration, so that
when we configure type/rate of fault injection through sysfs, mount
option, it will influence all f2fs partition which is being used.

It is not make sence, since it will be not convenient if developer want
to test separated partitions with different fault injection rate/type
simultaneously, also it's not possible to enable fault injection in one
partition and disable fault injection in other one.

>From now on, we move global configuration of fault injection in module
into per-superblock, hence injection testing can be more flexible.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:31 -07:00
Chao Yu
d32853de50 f2fs: adjust display format of segment bit
Just adjust segment bit info printed in procfs.

Before:
1008      5|0  |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1009      3|183|0 0 61 20 20 0 0 21 80 c0 2 e4 e 54 0 21 21 17 a 44 d0 28 e4 50 40 30 8 0 2d 32 0 5 b0 80 1 43 2 8e f8 7b 2 25 93 bf e0 73 8e 9a 19 44 60 ff e4 cc e6 8e bf f9 ff 5 3d 31 3d 13
1010      3|1  |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

After:
1008      5|0  | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1009      4|434| ff 7d ff bf d9 3f ff e7 ff bf d7 bf ff bb be ff fb df f7 fb fa bf fb fe bb df dd ff fe ef ff fe ef e2 27 bf ab bf fb df fd bd bf fb db fc ff ff 3f ff ff bf ff 5f db 3f fb fb bf fb bf 4f ff ef
1010      4|422| ff bb fe ff ef d7 ee ff ff fc bf ef 7d eb ec fd fb 3f 97 7f ef ff af ff db ff ff 69 bf ff f6 e7 ff fb f7 7b fb df be ff ff ef f3 fe ff ff df fe f7 fa ff b7 77 be fe fb a9 7f 87 a2 ac c7 ff 75

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:30 -07:00
Jaegeuk Kim
bb5dada7d2 f2fs: remove dirty inode pages in error path
When getting EIO while handling orphan inodes, we can get some dirty node
pages. Then, f2fs_write_node_pages() called by iput(node_inode) will try
to flush node pages. But in this case, we should prevent to do that, since
we will try again from the start.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:29 -07:00
Jaegeuk Kim
d41065e204 f2fs: handle errors during recover_orphan_inodes
This patch fixes to handle EIO during recover_orphan_inode() given the below
panic.

F2FS-fs : inject IO error in f2fs_read_end_io+0xe6/0x100 [f2fs]
------------[ cut here ]------------
RIP: 0010:[<ffffffffc0b244e3>]  [<ffffffffc0b244e3>] f2fs_evict_inode+0x433/0x470 [f2fs]
RSP: 0018:ffff92f8b7fb7c30  EFLAGS: 00010246
RAX: ffff92fb88a13500 RBX: ffff92f890566ea0 RCX: 00000000fd3c255c
RDX: 0000000000000001 RSI: ffff92fb88a13d90 RDI: ffff92fb8ee127e8
RBP: ffff92f8b7fb7c58 R08: 0000000000000001 R09: ffff92fb88a13d58
R10: 000000005a6a9373 R11: 0000000000000001 R12: 00000000fffffffb
R13: ffff92fb8ee12000 R14: 00000000000034ca R15: ffff92fb8ee12620
FS:  00007f1fefd8e880(0000) GS:ffff92fb95600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc211d34cdb CR3: 000000012d43a000 CR4: 00000000001406e0
Stack:
 ffff92f890566ea0 ffff92f890567078 ffffffffc0b5a0c0 ffff92f890566f28
 ffff92fb888b2000 ffff92f8b7fb7c80 ffffffffbc27ff55 ffff92f890566ea0
 ffff92fb8bf10000 ffffffffc0b5a0c0 ffff92f8b7fb7cb0 ffffffffbc28090d
Call Trace:
 [<ffffffffbc27ff55>] evict+0xc5/0x1a0
 [<ffffffffbc28090d>] iput+0x1ad/0x2c0
 [<ffffffffc0b3304c>] recover_orphan_inodes+0x10c/0x2e0 [f2fs]
 [<ffffffffc0b2e0f4>] f2fs_fill_super+0x884/0x1150 [f2fs]
 [<ffffffffbc2644ac>] mount_bdev+0x18c/0x1c0
 [<ffffffffc0b2d870>] ? f2fs_commit_super+0x100/0x100 [f2fs]
 [<ffffffffc0b2a755>] f2fs_mount+0x15/0x20 [f2fs]
 [<ffffffffbc264e49>] mount_fs+0x39/0x170
 [<ffffffffbc28555b>] vfs_kern_mount+0x6b/0x160
 [<ffffffffbc2881df>] do_mount+0x1cf/0xd00
 [<ffffffffbc287f2c>] ? copy_mount_options+0xac/0x170
 [<ffffffffbc289003>] SyS_mount+0x83/0xd0
 [<ffffffffbc8ee880>] entry_SYSCALL_64_fastpath+0x23/0xc1

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:27 -07:00
Chao Yu
aaec2b1d18 f2fs: introduce cp_lock to protect updating of ckpt_flags
This patch introduces spinlock to protect updating process of ckpt_flags
field in struct f2fs_checkpoint, it avoids incorrectly updating in race
condition.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: add __is_set_ckpt_flags likewise __set_ckpt_flags]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 17:34:20 -07:00
Jaegeuk Kim
a468f0ef51 f2fs: use crc and cp version to determine roll-forward recovery
Previously, we used cp_version only to detect recoverable dnodes.
In order to avoid same garbage cp_version, we needed to truncate the next
dnode during checkpoint, resulting in additional discard or data write.
If we can distinguish this by using crc in addition to cp_version, we can
remove this overhead.

There is backward compatibility concern where it changes node_footer layout.
So, this patch introduces a new checkpoint flag, CP_CRC_RECOVERY_FLAG, to
detect new layout. New layout will be activated only when this flag is set.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-30 10:05:46 -07:00
Chao Yu
8b038c70df f2fs: support IO error injection
This patch adds to support IO error injection for testing IO error
tolerance of f2fs.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-09-22 11:43:06 -07:00
Chao Yu
97c1794a5d f2fs: enable inline_dentry by default and add noinline_dentry option
Make inline_dentry as default mount option to improve space usage and
IO performance in scenario of numerous small directory.
It adds noinline_dentry mount option, instead.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-08-29 18:31:17 -07:00
Jaegeuk Kim
b873b798af Revert "f2fs: use percpu_rw_semaphore"
LKP reported -36.3% regression of fsmark.files_per_sec due to this patch.
I've confirmed that fxmark [1] has also slight regression for DWAL.

[1] https://github.com/sslab-gatech/fxmark

This reverts commit ec795418c4.
2016-08-19 11:15:08 +09:00
Linus Torvalds
6784725ab0 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "Assorted cleanups and fixes.

  Probably the most interesting part long-term is ->d_init() - that will
  have a bunch of followups in (at least) ceph and lustre, but we'll
  need to sort the barrier-related rules before it can get used for
  really non-trivial stuff.

  Another fun thing is the merge of ->d_iput() callers (dentry_iput()
  and dentry_unlink_inode()) and a bunch of ->d_compare() ones (all
  except the one in __d_lookup_lru())"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  fs/dcache.c: avoid soft-lockup in dput()
  vfs: new d_init method
  vfs: Update lookup_dcache() comment
  bdev: get rid of ->bd_inodes
  Remove last traces of ->sync_page
  new helper: d_same_name()
  dentry_cmp(): use lockless_dereference() instead of smp_read_barrier_depends()
  vfs: clean up documentation
  vfs: document ->d_real()
  vfs: merge .d_select_inode() into .d_real()
  unify dentry_iput() and dentry_unlink_inode()
  binfmt_misc: ->s_root is not going anywhere
  drop redundant ->owner initializations
  ufs: get rid of redundant checks
  orangefs: constify inode_operations
  missed comment updates from ->direct_IO() prototype change
  file_inode(f)->i_mapping is f->f_mapping
  trim fsnotify hooks a bit
  9p: new helper - v9fs_parent_fid()
  debugfs: ->d_parent is never NULL or negative
  ...
2016-07-28 12:59:05 -07:00
Chao Yu
82e0a5aa5d f2fs: fix to avoid data update racing between GC and DIO
Datas in file can be operated by GC and DIO simultaneously, so we will
face race case as below:

For write case:
Thread A				Thread B
- generic_file_direct_write
 - invalidate_inode_pages2_range
 - f2fs_direct_IO
  - do_blockdev_direct_IO
   - do_direct_IO
    - get_more_blocks
					- f2fs_gc
					 - do_garbage_collect
					  - gc_data_segment
					   - move_data_page
					    - do_write_data_page
					    migrate data block to new block address
   - dio_bio_submit
   update user data to old block address

For read case:
Thread A                                Thread B
- generic_file_direct_write
 - invalidate_inode_pages2_range
 - f2fs_direct_IO
  - do_blockdev_direct_IO
   - do_direct_IO
    - get_more_blocks
					- f2fs_balance_fs
					 - f2fs_gc
					  - do_garbage_collect
					   - gc_data_segment
					    - move_data_page
					     - do_write_data_page
					     migrate data block to new block address
					  - write_checkpoint
					   - do_checkpoint
					    - clear_prefree_segments
					     - f2fs_issue_discard
                                             discard old block adress
   - dio_bio_submit
   update user buffer from obsolete block address

In order to fix this, for one file, we should let DIO and GC getting exclusion
against with each other.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-15 15:21:22 -07:00
Jaegeuk Kim
b56ab837a0 f2fs: avoid mark_inode_dirty
Let's check inode's dirtiness before calling mark_inode_dirty.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08 10:34:09 -07:00
Chao Yu
3e6d0b4d9c f2fs: fix incorrect f_bfree calculation in ->statfs
As manual described, f_bfree indicates total free blocks in fs, in f2fs, it
includes two parts: visible free blocks and over-provision blocks. This
patch corrrects the calculation.

fsblkcnt_t   f_bfree;   /* free blocks in fs */

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08 10:33:32 -07:00
Jaegeuk Kim
ec795418c4 f2fs: use percpu_rw_semaphore
This patch replaces rw_semaphore with percpu_rw_semaphore for:
sbi->cp_rwsem
nm_i->nat_tree_lock

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08 10:33:31 -07:00
Chao Yu
64058be9c8 f2fs: add nodiscard mount option
This patch adds 'nodiscard' mount option.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08 10:33:26 -07:00
Jaegeuk Kim
52763a4b7a f2fs: detect host-managed SMR by feature flag
If mkfs.f2fs gives a feature flag for host-managed SMR, we can set mode=lfs
by default.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06 10:44:07 -07:00
Jaegeuk Kim
67c3758d22 f2fs: call update_inode_page for orphan inodes
Let's store orphan inode pages right away.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06 10:44:07 -07:00
Jaegeuk Kim
36abef4e79 f2fs: introduce mode=lfs mount option
This mount option is to enable original log-structured filesystem forcefully.
So, there should be no random writes for main area.

Especially, this supports host-managed SMR device.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-13 11:55:21 -07:00
Jaegeuk Kim
7dfeaa3220 f2fs: avoid reverse IO order for NODE and DATA
There is a data race between allocate_data_block() and f2fs_sbumit_page_mbio(),
which incur unnecessary reversed bio submission.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-08 10:25:50 -07:00
Jaegeuk Kim
9a449e9c3b f2fs: remove obsolete parameter in f2fs_truncate
We don't need lock parameter, which is always true.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-07 09:45:39 -07:00
Jaegeuk Kim
338bbfa086 f2fs: avoid wrong count on dirty inodes
The number should be covered by spin_lock. Otherwise we can see wrong count
in f2fs_stat.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-07 09:45:38 -07:00
Jaegeuk Kim
53aa6bbfda f2fs: inject to produce some orphan inodes
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:19 -07:00
Jaegeuk Kim
b93f771286 f2fs: remove writepages lock
This patch removes writepages lock.
We can improve multi-threading performance.

tiobench, 32 threads, 4KB write per fsync on SSD
Before: 25.88 MB/s
After: 28.03 MB/s

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:17 -07:00
Jaegeuk Kim
69e9e42744 f2fs: set flush_merge by default
This patch sets flush_merge by default.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:16 -07:00
Jaegeuk Kim
6d94c74ab8 f2fs: add lazytime mount option
This patch adds lazytime support.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:14 -07:00
Jaegeuk Kim
26de9b1171 f2fs: avoid unnecessary updating inode during fsync
If roll-forward recovery can recover i_size, we don't need to update inode's
metadata during fsync.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:13 -07:00
Jaegeuk Kim
0f18b462b2 f2fs: flush inode metadata when checkpoint is doing
This patch registers all the inodes which have dirty metadata to sync when
checkpoint is doing.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:11 -07:00
Jaegeuk Kim
fc9581c809 f2fs: introduce f2fs_i_size_write with mark_inode_dirty_sync
This patch introduces f2fs_i_size_write() to call mark_inode_dirty_sync() with
i_size_write().

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:08 -07:00
Jaegeuk Kim
91942321e4 f2fs: use inode pointer for {set, clear}_inode_flag
This patch refactors to use inode pointer for set_inode_flag and
clear_inode_flag.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-06-02 18:05:07 -07:00
Al Viro
84c60b1388 drop redundant ->owner initializations
it's not needed for file_operations of inodes located on fs defined
in the hosting module and for file_operations that go into procfs.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-29 19:08:00 -04:00
Tiezhu Yang
b8bef79df7 f2fs: make exit_f2fs_fs more clear
init_f2fs_fs does:
    1) f2fs_build_trace_ios
    2) init_inodecache
    3) create_node_manager_caches
    4) create_segment_manager_caches
    5) create_checkpoint_caches
    6) create_extent_cache
    7) kset_create_and_add
    8) kobject_init_and_add
    9) register_shrinker
    10) register_filesystem
    11) f2fs_create_root_stats
    12) proc_mkdir

exit_f2fs_fs should do cleanup in the reverse order
to make the code more clear.

Signed-off-by: Tiezhu Yang <kernelpatch@126.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-18 13:57:31 -07:00
Jaegeuk Kim
513c5f3735 f2fs: use percpu_counter for total_valid_inode_count
This patch uses percpu_counter to avoid stat_lock.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-18 13:57:30 -07:00
Jaegeuk Kim
41382ec432 f2fs: use percpu_counter for alloc_valid_block_count
This patch uses percpu_count for sbi->alloc_valid_block_count.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-18 13:57:29 -07:00
Jaegeuk Kim
1beba1b3a9 f2fs: use percpu_counter for # of dirty pages in inode
This patch adds percpu_counter for # of dirty pages in inode.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-18 13:57:28 -07:00
Jaegeuk Kim
523be8a6b3 f2fs: use percpu_counter for page counters
This patch substitutes percpu_counter for atomic_counter when counting
various types of pages.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-18 13:57:27 -07:00
Jaegeuk Kim
f573018491 f2fs: use bio count instead of F2FS_WRITEBACK page count
This can reduce page counting overhead.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-18 13:57:25 -07:00
Sheng Yong
087968974f f2fs: add fault injection to sysfs
This patch introduces a new struct f2fs_fault_info and a global f2fs_fault
to save fault injection status. Fault injection entries are created in
/sys/fs/f2fs/fault_injection/ during initializing f2fs module.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-16 15:32:02 -07:00
Sheng Yong
99e3e858a4 f2fs: correct return value type of f2fs_fill_super
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-16 15:31:59 -07:00
Jaegeuk Kim
b5a7aef1ef fscrypto/f2fs: allow fs-specific key prefix for fs encryption
This patch allows fscrypto to handle a second key prefix given by filesystem.
The main reason is to provide backward compatibility, since previously f2fs
used "f2fs:" as a crypto prefix instead of "fscrypt:".
Later, ext4 should also provide key_prefix() to give "ext4:".

One concern decribed by Ted would be kinda double check overhead of prefixes.
In x86, for example, validate_user_key consumes 8 ms after boot-up, which turns
out derive_key_aes() consumed most of the time to load specific crypto module.
After such the cold miss, it shows almost zero latencies, which treats as a
negligible overhead.
Note that request_key() detects wrong prefix in prior to derive_key_aes() even.

Cc: Ted Tso <tytso@mit.edu>
Cc: stable@vger.kernel.org # v4.6
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:33 -07:00
Jaegeuk Kim
74ef924167 f2fs: fix leak of orphan inode objects
When unmounting filesystem, we should release all the ino entries.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:25 -07:00
Jaegeuk Kim
cb78942b82 f2fs: inject ENOSPC failures
This patch injects ENOSPC failures.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:24 -07:00
Jaegeuk Kim
c41f3cc3ae f2fs: inject page allocation failures
This patch adds page allocation failures.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:23 -07:00
Jaegeuk Kim
2c63fead9e f2fs: inject kmalloc failure
This patch injects kmalloc failure given a fault injection rate.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:22 -07:00
Jaegeuk Kim
73faec4d99 f2fs: add mount option to select fault injection ratio
This patch adds a mount option to select fault ratio.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:22 -07:00
Jaegeuk Kim
f00d6fa727 f2fs: add proc entry to show valid block bitmap
This patch adds a new proc entry to show segment information in more detail.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:19 -07:00
Jaegeuk Kim
b7a15f3dbe f2fs: introduce macros for proc entries
This adds macros to be used multiple proc entries.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-05-07 10:32:18 -07:00
Jaegeuk Kim
faa0e55bba f2fs: treat as a normal umount when remounting ro
When user remounts f2fs as read-only, we can mark the checkpoint as umount.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-04-15 08:49:47 -07:00