Commit Graph

314 Commits

Author SHA1 Message Date
Chao Yu 91c481fff9 f2fs: add largest/cached stat in extent cache
This patch adds to stat the hit count of largest/cached node for showing
in debugfs.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-21 22:45:15 -07:00
Chao Yu e2b4e2bc88 f2fs: fix incorrect mapping for bmap
The test step is like below:
1. touch file
2. truncate -s $((1024*1024)) file
3. fallocate -o 0 -l $((1024*1024)) file
4. fibmap.f2fs file

Our result of fibmap.f2fs showed below is not correct:

file_pos   start_blk     end_blk        blks
       0    -937166132    -937166132           1
    4096    -937166132    -937166132           1
    8192    -937166132    -937166132           1
   12288    -937166132    -937166132           1
   16384    -937166132    -937166132           1
   20480    -937166132    -937166132           1
...
 1040384    -937166132    -937166132           1
 1044480    -937166132    -937166132           1

This is because f2fs_map_blocks will return with no error when meeting
a hole or preallocated block, the caller __get_data_block will map the
uninitialized variable value to bh->b_blocknr.

Unfortunately generic_block_bmap will neither check the return value of
get_data() nor check mapping info of buffer_head, result in returning
the random block address.

After fixing the issue, our result shows correctly:

file_pos   start_blk     end_blk        blks
       0           0           0         256

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-21 22:45:14 -07:00
Jaegeuk Kim 740432f835 f2fs: handle failed bio allocation
As the below comment of bio_alloc_bioset, f2fs can allocate multiple bios at the
same time. So, we can't guarantee that bio is allocated all the time.

"
 *   When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
 *   able to allocate a bio. This is due to the mempool guarantees. To make this
 *   work, callers must never allocate more than 1 bio at a time from this pool.
 *   Callers that need to allocate more than 1 bio must always submit the
 *   previously allocated bio for IO before attempting to allocate a new one.
 *   Failure to do so can cause deadlocks under memory pressure.
"

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-20 09:00:09 -07:00
Jaegeuk Kim a6db67f06f f2fs: increase the number of max hard links
This patch increases the number of maximum hard links for one file.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-20 09:00:08 -07:00
Chao Yu 31696580bf f2fs: shrink free_nids entries
This patch introduces __count_free_nids/try_to_free_nids and registers
them in slab shrinker for shrinking under memory pressure.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-20 09:00:06 -07:00
Chao Yu 8c14bfadea f2fs: handle error of f2fs_iget correctly
In recover_orphan_inode, whenever f2fs_iget fail, we will make kernel panic,
but it's not reasonable, because f2fs_iget can fail due to a lot of reasons
including out of memory.

So we change error handling method as below:
a) when finding no entry for the orphan inode, bug_on for catching bugs;
b) for other reasons, report it to caller.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-14 16:02:14 -07:00
Chao Yu decd36b6c4 f2fs: remove inmem radix tree
Previously, we use radix tree to index all registered page entries for
atomic file, but now we only use radix tree to see whether current page
is indexed or not, since the other user of radix tree is gone in commit
042b7816aa ("f2fs: remove unnecessary call to invalidate inmemory pages").

So in this patch, we try to use one more efficient way:
Introducing a macro ATOMIC_WRITTEN_PAGE, and setting it as page private
value to indicate page indexing status. By using this way, we can save
memory and lookup time.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-11 11:31:14 -07:00
Fan Li 759af1c9c1 f2fs: use extent cache to optimize f2fs_reserve_block
In some cases, we only need the block address when we call
f2fs_reserve_block,
other fields of struct dnode_of_data aren't necessary.
We can try extent cache first for such cases in order to speed up the
process.

Signed-off-by: Fan li <fanofcode.li@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-05 22:15:42 -07:00
Chao Yu e90c2d2850 f2fs: invalidate temporary meta page
To avoid meeting garbage data in next free node block at the end of warm
node chain when doing recovery, we will try to zero out that invalid block.

If the device is not support discard, our way for zeroing out block is:
grabbing a temporary zeroed page in meta inode, then, issue write request
with this page.

But, we forget to release that temporary page, so our memory usage will
increase without gaining any hit ratio benefit, so it's better to free it
for saving memory.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-05 08:19:21 -07:00
Jaegeuk Kim edb27deea7 f2fs: handle error cases in commit_inmem_pages
This patch adds to handle error cases in commit_inmem_pages.
If an error occurs, it stops to write the pages and return the error right
away.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-05 08:08:15 -07:00
Chao Yu 55f57d2c42 f2fs: fix double lock in handle_failed_inode
In handle_failed_inode, there is a potential deadlock which can happen
in below call path:

- f2fs_create
 - f2fs_lock_op   down_read(cp_rwsem)
 - f2fs_add_link
  - __f2fs_add_link
   - init_inode_metadata
    - f2fs_init_security    failed
    - truncate_blocks    failed
 - handle_failed_inode
  - f2fs_truncate
   - truncate_blocks(..,true)
					- write_checkpoint
					 - block_operations
					  - f2fs_lock_all  down_write(cp_rwsem)
    - f2fs_lock_op   down_read(cp_rwsem)

So in this path, we pass parameter to f2fs_truncate to make sure
cp_rwsem in truncate_blocks will not be locked again.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-05 08:08:09 -07:00
Chao Yu 727edac572 f2fs: use atomic_t to record hit ratio info of extent cache
Variables for recording extent cache ratio info were updated without
protection, this patch tries to alter them to atomic_t type for more
accurate stat.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-05 08:08:06 -07:00
Chao Yu d5e8f6c980 f2fs: stat inline xattr inode number
This patch adds to stat the number of inline xattr inode for
showing in debugfs.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-05 08:08:05 -07:00
Chao Yu c1c1b58359 f2fs: add new ioctl F2FS_IOC_GARBAGE_COLLECT
When background gc is off, the only way to trigger gc is executing
a force gc in some operations who wants to grab space in disk.

The executing condition is limited: to execute force gc, we should
wait for the time when there is almost no more free section for LFS
allocation. This seems not reasonable for our user who wants to
control triggering gc by himself.

This patch introduces F2FS_IOC_GARBAGE_COLLECT interface for
triggering garbage collection by using ioctl. It provides our users
one more option to trigger gc.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:58 -07:00
Chao Yu a28ef1f5ae f2fs: maintain extent cache in separated file
This patch moves extent cache related code from data.c into extent_cache.c
since extent cache is independent feature, and its codes are not relate to
others in data.c, it's better for us to maintain them in separated place.

There is no functionality change, but several small coding style fixes
including:
* rename __drop_largest_extent to f2fs_drop_largest_extent for exporting;
* rename misspelled word 'untill' to 'until';
* remove unneeded 'return' in the end of f2fs_destroy_extent_tree().

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:58 -07:00
Jaegeuk Kim 3e72f72139 f2fs: use extent_cache by default
We don't need to handle the duplicate extent information.

The integrated rule is:
 - update on-disk extent with largest one tracked by in-memory extent_cache
 - destroy extent_tree for the truncation case
 - drop per-inode extent_cache by shrinker

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:56 -07:00
Jaegeuk Kim 554df79e52 f2fs: shrink extent_cache entries
This patch registers shrinking extent_caches.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:55 -07:00
Jaegeuk Kim 2658e50de6 f2fs: introduce a shrinker for mounted fs
This patch introduces a shrinker targeting to reduce memory footprint consumed
by a number of in-memory f2fs data structures.

In addition, it newly adds:
 - sbi->umount_mutex to avoid data races on shrinker and put_super
 - sbi->shruinker_run_no to not revisit objects

Note that the basic implementation was copied from fs/ubifs/shrinker.c

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:54 -07:00
Jaegeuk Kim c9b63bd01d f2fs: avoid to use failed inode immediately
Before iput is called, the inode number used by a bad inode can be reassigned
to other new inode, resulting in any abnormal behaviors on the new inode.
This should not happen for the new inode.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:53 -07:00
Chao Yu 5ac9f36fca f2fs: fix to record dirty page count for symlink
Dirty page can be exist in mapping of newly created symlink, but previously
we did not maintain the counting of dirty page for symlink like we maintained
for regular/directory, so the counting we lookuped should be wrong.

This patch adds missed dirty page counting for symlink to fix this issue.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-08-04 14:09:52 -07:00
Chao Yu c5bda1c8b1 f2fs: skip committing valid superblock
In recovery procedure for superblock, we try to write data of valid
superblock into invalid one for recovery, work should be finished here,
but then still we will write the valid one with its original data.
This operation is not needed. Let's skip doing this unnecessary work.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-06-08 11:20:51 -07:00
Chao Yu 528e34593d f2fs: hide common code in f2fs_replace_block
This patch clean up codes through:
1.rename f2fs_replace_block to __f2fs_replace_block().
2.introduce new f2fs_replace_block() to include __f2fs_replace_block()
and some common related codes around __f2fs_replace_block().

Then, newly introduced function f2fs_replace_block can be used by
following patch.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-06-02 09:52:07 -07:00
Jaegeuk Kim 26bf3dc7e2 f2fs crypto: use per-inode tfm structure
This patch applies the following ext4 patch:

  ext4 crypto: use per-inode tfm structure

As suggested by Herbert Xu, we shouldn't allocate a new tfm each time
we read or write a page.  Instead we can use a single tfm hanging off
the inode's crypt_info structure for all of our encryption needs for
that inode, since the tfm can be used by multiple crypto requests in
parallel.

Also use cmpxchg() to avoid races that could result in crypt_info
structure getting doubly allocated or doubly freed.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-06-01 16:21:04 -07:00
Chao Yu 381722d2ac f2fs: introduce update_meta_page
Add a help function update_meta_page() to update meta page with specified
buffer.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-06-01 16:21:00 -07:00
Jaegeuk Kim cfc4d971df f2fs crypto: split f2fs_crypto_init/exit with two parts
This patch splits f2fs_crypto_init/exit with two parts: base initialization and
memory allocation.

Firstly, f2fs module declares the base encryption memory pointers.
Then, allocating internal memories is done at the first encrypted inode access.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-06-01 16:20:59 -07:00
Jaegeuk Kim 8bacf6deb0 f2fs crypto: use slab caches
This patch integrates the below patch into f2fs.

"ext4 crypto: use slab caches

Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for
slighly better memory efficiency and debuggability."

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-06-01 16:20:55 -07:00
Jaegeuk Kim cbaf042a3c f2fs crypto: add symlink encryption
This patch implements encryption support for symlink.

Signed-off-by: Uday Savagaonkar <savagaon@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:55 -07:00
Jaegeuk Kim e7d5545285 f2fs crypto: add filename encryption for roll-forward recovery
This patch adds a bit flag to indicate whether or not i_name in the inode
is encrypted.

If this name is encrypted, we can't do recover_dentry during roll-forward.
So, f2fs_sync_file() needs to do checkpoint, if this will be needed in future.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:55 -07:00
Jaegeuk Kim 6e22c691ba f2fs crypto: add filename encryption for f2fs_lookup
This patch implements filename encryption support for f2fs_lookup.

Note that, f2fs_find_entry should be outside of f2fs_(un)lock_op().

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:54 -07:00
Jaegeuk Kim d8c6822a05 f2fs crypto: add filename encryption for f2fs_readdir
This patch implements filename encryption support for f2fs_readdir.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:53 -07:00
Jaegeuk Kim 4375a33664 f2fs crypto: add encryption support in read/write paths
This patch adds encryption support in read and write paths.

Note that, in f2fs, we need to consider cleaning operation.
In cleaning procedure, we must avoid encrypting and decrypting written blocks.
So, this patch implements move_encrypted_block().

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:52 -07:00
Jaegeuk Kim fcc85a4d86 f2fs crypto: activate encryption support for fs APIs
This patch activates the following APIs for encryption support.

The rules quoted by ext4 are:
 - An unencrypted directory may contain encrypted or unencrypted files
   or directories.
 - All files or directories in a directory must be protected using the
   same key as their containing directory.
 - Encrypted inode for regular file should not have inline_data.
 - Encrypted symlink and directory may have inline_data and inline_dentry.

This patch activates the following APIs.
1. f2fs_link              : validate context
2. f2fs_lookup            :      ''
3. f2fs_rename            :      ''
4. f2fs_create/f2fs_mkdir : inherit its dir's context
5. f2fs_direct_IO         : do buffered io for regular files
6. f2fs_open              : check encryption info
7. f2fs_file_mmap         :      ''
8. f2fs_setattr           :      ''
9. f2fs_file_write_iter   :      ''           (Called by sys_io_submit)
10. f2fs_fallocate        : do not support fcollapse
11. f2fs_evict_inode      : free_encryption_info

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:51 -07:00
Jaegeuk Kim 6b3bd08f93 f2fs crypto: filename encryption facilities
This patch adds filename encryption infra.
Most of codes are copied from ext4 part, but changed to adjust f2fs
directory structure.

Signed-off-by: Uday Savagaonkar <savagaon@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:50 -07:00
Jaegeuk Kim 0adda907f2 f2fs crypto: add encryption key management facilities
This patch copies from encrypt_key.c in ext4, and modifies for f2fs.

Use GFP_NOFS, since _f2fs_get_encryption_info is called under f2fs_lock_op.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Ildar Muslukhov <muslukhovi@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:49 -07:00
Jaegeuk Kim 57e5055b0a f2fs crypto: add f2fs encryption facilities
Most of parts were copied from ext4, except:

 - add f2fs_restore_and_release_control_page which returns control page and
   restore control page
 - remove ext4_encrypted_zeroout()
 - remove sbi->s_file_encryption_mode & sbi->s_dir_encryption_mode
 - add f2fs_end_io_crypto_work for mpage_end_io

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:49 -07:00
Jaegeuk Kim f424f664f0 f2fs crypto: add encryption policy and password salt support
This patch adds encryption policy and password salt support through ioctl
implementation.

It adds three ioctls:
 F2FS_IOC_SET_ENCRYPTION_POLICY,
 F2FS_IOC_GET_ENCRYPTION_POLICY,
 F2FS_IOC_GET_ENCRYPTION_PWSALT, which use xattr operations.

Note that, these definition and codes are taken from ext4 crypto support.
For f2fs, xattr operations and on-disk flags for superblock and inode were
changed.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ildar Muslukhov <muslukhovi@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:48 -07:00
Jaegeuk Kim cde4de1205 f2fs crypto: declare some definitions for f2fs encryption feature
This definitions will be used by inode and superblock for encyption.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:45 -07:00
Jaegeuk Kim 7f63eb77af f2fs: report unwritten area in f2fs_fiemap
This patch slightly changes f2fs_fiemap function to report unwritten area.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:45 -07:00
Chao Yu 19f106bc03 f2fs: introduce f2fs_replace_block() for reuse
Introduce a generic function replace_block base on recover_data_page,
and export it. So with it we can operate file's meta data which is in
CP/SSA area when we invoke fallocate with FALLOC_FL_COLLAPSE_RANGE
flag.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:42 -07:00
Chao Yu 402f721d2f f2fs: remove unneeded f2fs_make_empty declaration
Remove f2fs_make_empty() declaration, since the main body of this function
is move into do_make_empty_dir() and the function is obsolete now.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:40 -07:00
Jaegeuk Kim 836b5a6356 f2fs: issue discard with finally produced len and minlen
This patch determines to issue discard commands by comparing given minlen and
the length of produced final candidates.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:39 -07:00
Jaegeuk Kim a66cdd9855 f2fs: introduce discard_map for f2fs_trim_fs
This patch adds a bitmap for discard issues from f2fs_trim_fs.
There-in rule is to issue discard commands only for invalidated blocks
after mount.
Once mount is done, f2fs_trim_fs trims out whole invalid area.
After ehn, it will not issue and discrads redundantly.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:39 -07:00
Jaegeuk Kim 43f3eae1d3 f2fs: split find_data_page according to specific purposes
This patch splits find_data_page as follows.

1. f2fs_gc
 - use get_read_data_page() with read only

2. find_in_level
 - use find_data_page without locked page

3. truncate_partial_page
 - In the case cache_only mode, just drop cached page.
 - Ohterwise, use get_lock_data_page() and guarantee to truncate

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:37 -07:00
Jaegeuk Kim 2dcf51ab2f f2fs: add need_dentry_mark
This patch introduces need_dentry_mark() to clean up and avoid redundant
node locks.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:36 -07:00
Jaegeuk Kim eaa693f4dc f2fs: introduce dot and dotdot name check
This patch adds an inline function to check dot and dotdot names.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:34 -07:00
Jaegeuk Kim 05ca3632e5 f2fs: add sbi and page pointer in f2fs_io_info
This patch adds f2fs_sb_info and page pointers in f2fs_io_info structure.
With this change, we can reduce a lot of parameters for IO functions.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:32 -07:00
Jaegeuk Kim 01b960e94a f2fs: add f2fs_may_inline_{data, dentry}
This patch adds f2fs_may_inline_data and f2fs_may_inline_dentry.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:32 -07:00
Jaegeuk Kim 26d815ad75 f2fs: introduce f2fs_commit_super
This patch introduces f2fs_commit_super to write updated superblock.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:29 -07:00
Jaegeuk Kim 003a3e1d60 f2fs: add f2fs_map_blocks
This patch introduces f2fs_map_blocks structure likewise ext4_map_blocks.
Now, f2fs uses f2fs_map_blocks when handling get_block.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:29 -07:00
Jaegeuk Kim 76f105a2db f2fs: add feature facility in superblock
This patch introduces a feature in superblock, which will indicate any new
features for f2fs.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2015-05-28 15:41:28 -07:00