As the description of rename in manual, RENAME_WHITEOUT is a special operation
that only makes sense for overlay/union type filesystem.

When performing rename with RENAME_WHITEOUT, dst will be replace with src, and
meanwhile, a 'whiteout' will be create with name of src.

A "whiteout" is designed to be a char device with 0,0 device number, it has
specially meaning for stackable filesystem. In these filesystems, there are
multiple layers exist, and only top of these can be modified. So a whiteout
in top layer is used to hide a corresponding file in lower layer, as well
removal of whiteout will make the file appear.

Now in overlayfs, when we rename a file which is exist in lower layer, it
will be copied up to upper if it is not on upper layer yet, and then rename
it on upper layer, source file will be whiteouted to hide corresponding file
in lower layer at the same time.

So in upper layer filesystem, implementation of RENAME_WHITEOUT provide a
atomic operation for stackable filesystem to support rename operation.

There are multiple ways to implement RENAME_WHITEOUT in log of this commit:
7dcf5c3e ("xfs: add RENAME_WHITEOUT support") which pointed out by
Dave Chinner.

For now, we just try to follow the way that xfs/ext4 use.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

Now page cache of meta inode is used by garbage collection for encrypted page,
it may contain random data, so we should zero it before issuing discard.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

When encryption feature is enable, if we rmmod f2fs module,
we will encounter a stack backtrace reported in syslog:

"BUG: Bad page state in process rmmod  pfn:aaf8a
page:f0f4f148 count:0 mapcount:129 mapping:ee2f4104 index:0x80
flags: 0xee2830a4(referenced|lru|slab|private_2|writeback|swapbacked|mlocked)
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
bad because of flags:
flags: 0x2030a0(lru|slab|private_2|writeback|mlocked)
Modules linked in: f2fs(O-) fuse bnep rfcomm bluetooth dm_crypt binfmt_misc snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm
snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device joydev ppdev mac_hid lp hid_generic i2c_piix4
parport_pc psmouse snd serio_raw parport soundcore ext4 jbd2 mbcache usbhid hid e1000 [last unloaded: f2fs]
CPU: 1 PID: 3049 Comm: rmmod Tainted: G    B      O    4.1.0-rc3+ #10
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
00000000 00000000 c0021eb4 c15b7518 f0f4f148 c0021ed8 c112e0b7 c1779174
c9b75674 000aaf8a 01b13ce1 c17791a4 f0f4f148 ee2830a4 c0021ef8 c112e3c3
00000000 f0f4f148 c0021f34 f0f4f148 ee2830a4 ef9f0000 c0021f20 c112fdf8
Call Trace:
[<c15b7518>] dump_stack+0x41/0x52
[<c112e0b7>] bad_page.part.72+0xa7/0x100
[<c112e3c3>] free_pages_prepare+0x213/0x220
[<c112fdf8>] free_hot_cold_page+0x28/0x120
[<c1073380>] ? try_to_wake_up+0x2b0/0x2b0
[<c112ff15>] __free_pages+0x25/0x30
[<c112c4fd>] mempool_free_pages+0xd/0x10
[<c112c5f1>] mempool_free+0x31/0x90
[<f0f441cf>] f2fs_exit_crypto+0x6f/0xf0 [f2fs]
[<f0f456c4>] exit_f2fs_fs+0x23/0x95f [f2fs]
[<c10c30e0>] SyS_delete_module+0x130/0x180
[<c11556d6>] ? vm_munmap+0x46/0x60
[<c15bd888>] sysenter_do_call+0x12/0x12"

The reason is that:

since commit 0827e645fd35
("f2fs crypto: shrink size of the f2fs_crypto_ctx structure") is merged,
some fields in f2fs_crypto_ctx structure are merged into a union as they
will never be used simultaneously in write path, read path or on free list.

In f2fs_exit_crypto, we traverse each crypto ctx from free list, in this
moment, our free_list field in union is valid, but still we will try to
release memory space which is pointed by other invalid field in union
structure for each ctx.

Then the error occurs, let's fix it with this patch.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch fixes memory leak issue in error path of f2fs_fname_setup_filename().
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch integrates the below patch into f2fs.

"ext4 crypto: shrink size of the ext4_crypto_ctx structure

Some fields are only used when the crypto_ctx is being used on the
read path, some are only used on the write path, and some are only
used when the structure is on free list.  Optimize memory use by using
a union."
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch integrates the below patch into f2fs.

"ext4 crypto: get rid of ci_mode from struct ext4_crypt_info

The ci_mode field was superfluous, and getting rid of it gets rid of
an unused hole in the structure."
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

As Hu reported, F2FS has a space leak problem, when conducting:

1) format a 4GB f2fs partition
2) dd a 3G file,
3) unlink it.

So, when doing f2fs_drop_inode(), we need to truncate data blocks
before skipping it.
We can also drop unused caches assigned to each inode.
Reported-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

The return was not indented far enough so it looked like it was supposed
to go with the other if statement.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

A bug fix to the debug output extended the type of some local
variables to 64-bit, which now causes the kernel to fail building
because of missing 64-bit division functions:

ERROR: "__aeabi_uldivmod" [fs/f2fs/f2fs.ko] undefined!

In the kernel, we have to use div_u64 or do_div to do this,
in order to annotate that this is an expensive operation.

As the function is only called for debug out, we know this
is not performance critical, so it is safe to use div_u64.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: d1f85bd38db19 ("f2fs: avoid value overflow in showing current status")
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch avoids to use a buggy function for now.
It needs to fix them later.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

introduce compat_ioctl to regular files, but doesn't add this
functionality to f2fs_dir_operations.

While running a 32-bit busybox, I met an error like this:
(A is a directory)

chattr: reading flags on A: Inappropriate ioctl for device

This patch copies compat_ioctl from f2fs_file_operations and
fix this problem.
Signed-off-by: hujianyang <hujianyang@huawei.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

We have a discard map, so that we can avoid redundant discard issues.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

I use f2fs filesystem with /data partition on my Android phone
by the default mount options. When I remount /data in order to
adding discard option to run some benchmarks, I find the default
options such as background_gc, user_xattr and acl turned off.

So I introduce a function named default_options in super.c. It do
some default setting, and both mount and remount operations will
call this function to complete default setting.
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

No matter what the key is valid or not, readdir shows the dir entries correctly.
So, lookup should not failed.
But, we expect further accesses should be denied from open, rename, link, and so
on.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1. mount $mnt
2. cp data $mnt/
3. umount $mnt
4. log out
5. log in
6. cat $mnt/data

-> panic, due to no i_crypt_info.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

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>

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>

This patch implements filename encryption support for f2fs_readdir.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch adds filename encryption support for f2fs_add_link.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

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>

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>

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>

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>

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>

This patch add some definition for enrcyption xattr.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch adds f2fs encryption config.

This patch integrates:

"ext4 crypto: require CONFIG_CRYPTO_CTR if ext4 encryption is enabled

On arm64 this is apparently needed for CTS mode to function correctly.
Otherwise attempts to use CTS return ENOENT."
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>

This definitions will be used by inode and superblock for encyption.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch slightly changes f2fs_fiemap function to report unwritten area.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch fixes overflow when do cat /sys/kernel/debug/f2fs/status.
If a section is relatively large, dist value can be overflowed.
Reported-by: Yossi Goldfill <ygoldfill@radianmemory.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Now, FALLOC_FL_ZERO_RANGE flag in ->fallocate is supported in ext4/xfs.

In commit, the semantics of this flag is descripted as following:"
1) Make sure that both offset and len are block size aligned.
2) Update the i_size of inode by len bytes.
3) Compute the file's logical block number against offset. If the computed
   block number is not the starting block of the extent, split the extent
   such that the block number is the starting block of the extent.
4) Shift all the extents which are lying between
   [offset, last allocated extent] towards right by len bytes. This step
   will make a hole of len bytes at offset."

This patch implements fallocate's FALLOC_FL_ZERO_RANGE for f2fs.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Now, FALLOC_FL_COLLAPSE_RANGE flag in ->fallocate is supported in ext4/xfs.

In commit, the semantics of this flag is descripted as following:"
1) It collapses the range lying between offset and length by removing any
   data blocks which are present in this range and than updates all the
   logical offsets of extents beyond "offset + len" to nullify the hole
   created by removing blocks. In short, it does not leave a hole.
2) It should be used exclusively. No other fallocate flag in combination.
3) Offset and length supplied to fallocate should be fs block size aligned
   in case of xfs and ext4.
4) Collaspe range does not work beyond i_size."

This patch implements fallocate's FALLOC_FL_COLLAPSE_RANGE for f2fs.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

In set_node_addr, we try to lookup cached nat entry of inode and then
set flag in it.

But previously in this function, we have already grabbed nat entry with
current node id, if the node id is the same as the one of inode, we
do not need to lookup it in cache again.

So this patch adds condition judgment for reducing unneeded lookup.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

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>

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>