The cgroup attaches inode->i_wb via mark_inode_dirty and when set_page_writeback
is called, __inc_wb_stat() updates i_wb's stat.

So, we need to explicitly call set_page_dirty->__mark_inode_dirty in prior to
any writebacking pages.

This patch should resolve the following kernel panic reported by Andreas Reis.

https://bugzilla.kernel.org/show_bug.cgi?id=101801

--- Comment #2 from Andreas Reis <andreas.reis@gmail.com> ---
BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
IP: [<ffffffff8149deea>] __percpu_counter_add+0x1a/0x90
PGD 2951ff067 PUD 2df43f067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU: 7 PID: 10356 Comm: gcc Tainted: G        W       4.2.0-1-cu #1
Hardware name: Gigabyte Technology Co., Ltd. G1.Sniper M5/G1.Sniper M5, BIOS
T01 02/03/2015
task: ffff880295044f80 ti: ffff880295140000 task.ti: ffff880295140000
RIP: 0010:[<ffffffff8149deea>]  [<ffffffff8149deea>]
__percpu_counter_add+0x1a/0x90
RSP: 0018:ffff880295143ac8  EFLAGS: 00010082
RAX: 0000000000000003 RBX: ffffea000a526d40 RCX: 0000000000000001
RDX: 0000000000000020 RSI: 0000000000000001 RDI: 0000000000000088
RBP: ffff880295143ae8 R08: 0000000000000000 R09: ffff88008f69bb30
R10: 00000000fffffffa R11: 0000000000000000 R12: 0000000000000088
R13: 0000000000000001 R14: ffff88041d099000 R15: ffff880084a205d0
FS:  00007f8549374700(0000) GS:ffff88042f3c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000a8 CR3: 000000033e1d5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 ffffea000a526d40 ffff880084a20738 ffff880084a20750
 ffff880295143b48 ffffffff811cc91e ffff880000000000 0000000000000296
 0000000000000000 ffff880417090198 0000000000000000 ffffea000a526d40
Call Trace:
 [<ffffffff811cc91e>] __test_set_page_writeback+0xde/0x1d0
 [<ffffffff813fee87>] do_write_data_page+0xe7/0x3a0
 [<ffffffff813faeea>] gc_data_segment+0x5aa/0x640
 [<ffffffff813fb0b8>] do_garbage_collect+0x138/0x150
 [<ffffffff813fb3fe>] f2fs_gc+0x1be/0x3e0
 [<ffffffff81405541>] f2fs_balance_fs+0x81/0x90
 [<ffffffff813ee357>] f2fs_unlink+0x47/0x1d0
 [<ffffffff81239329>] vfs_unlink+0x109/0x1b0
 [<ffffffff8123e3d7>] do_unlinkat+0x287/0x2c0
 [<ffffffff8123ebc6>] SyS_unlink+0x16/0x20
 [<ffffffff81942e2e>] entry_SYSCALL_64_fastpath+0x12/0x71
Code: 41 5e 5d c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 55 49
89 f5 41 54 49 89 fc 53 48 83 ec 08 65 ff 05 e6 d9 b6 7e <48> 8b 47 20 48 63 ca
65 8b 18 48 63 db 48 01 f3 48 39 cb 7d 0a
RIP  [<ffffffff8149deea>] __percpu_counter_add+0x1a/0x90
 RSP <ffff880295143ac8>
CR2: 00000000000000a8
---[ end trace 5132449a58ed93a3 ]---
note: gcc[10356] exited with preempt_count 2
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes some missing error handlers.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When we perform generic/092 in xfstests, output is like below:

     XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
     0: [0..10239]: data
     0: [0..10239]: data
    -1: [10240..20479]: unwritten
    +1: [10240..14335]: unwritten

This is because with this testcase, we redefine the regulation for
truncate in perallocated space past i_size as below:

"There was some confused about what the fs was supposed to do when you
truncate at i_size with preallocated space past i_size. We decided on the
following things.

1) truncate(i_size) will trim all blocks past i_size.
2) truncate(x) where x > i_size will not trim all blocks past i_size.
"

This method is used in xfs, and then ext4/btrfs will follow the rule.

This patch fixes to follow the new rule for f2fs.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds alloc_bounce_page likewise ext4.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch makes some error handling policies same with ext4.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When aborting volatile_writes, let's drop its flag and give up any further
volatile_writes.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

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: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For the first mount of f2fs image with realtime discard option, we will
disable discard option if device is not supported, but for remount
operation, our discard option can still be set, this should be avoided.

This patch moves configuring of discard option to parse_options() to fix
this issue.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Now, we add all the candidates for trim commands and then finally issue
discard commands.
So, we should count the trimmed size in back-end.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

FALLOC_FL_INSERT_RANGE flag for ->fallocate was introduced in commit
dd46c787 ("fs: Add support FALLOC_FL_INSERT_RANGE for fallocate").

The effect of FALLOC_FL_INSERT_RANGE command is the opposite of
FALLOC_FL_COLLAPSE_RANGE, if this command was performed, all data from
offset to EOF in our file will be shifted to right as given length, and
then range [offset, offset + length] becomes a hole.

This command is useful for our user who wants to add some data in the
middle of the file, for example: video/music editor will insert a keyframe
in specified position of media file, with this command we can easily create
a hole for inserting without removing original data.

This patch introduces f2fs_insert_range() to support FALLOC_FL_INSERT_RANGE.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NYuan Zhong <yuan.mark.zhong@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

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: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

With the planned cgroup writeback support, backing-dev related
declarations will be more widely used across block and cgroup;
unfortunately, including backing-dev.h from include/linux/blkdev.h
makes cyclic include dependency quite likely.

This patch separates out backing-dev-defs.h which only has the
essential definitions and updates blkdev.h to include it.  c files
which need access to more backing-dev details now include
backing-dev.h directly.  This takes backing-dev.h off the common
include dependency chain making it a lot easier to use it across block
and cgroup.

v2: fs/fat build failure fixed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NJens Axboe <axboe@fb.com>

Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear.  For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi.  To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.

This patch moves bandwidth related fields from backing_dev_info into
bdi_writeback.

* The moved fields are: bw_time_stamp, dirtied_stamp, written_stamp,
  write_bandwidth, avg_write_bandwidth, dirty_ratelimit,
  balanced_dirty_ratelimit, completions and dirty_exceeded.

* writeback_chunk_size() and over_bground_thresh() now take @wb
  instead of @bdi.

* bdi_writeout_fraction(bdi, ...)	-> wb_writeout_fraction(wb, ...)
  bdi_dirty_limit(bdi, ...)		-> wb_dirty_limit(wb, ...)
  bdi_position_ration(bdi, ...)		-> wb_position_ratio(wb, ...)
  bdi_update_writebandwidth(bdi, ...)	-> wb_update_write_bandwidth(wb, ...)
  [__]bdi_update_bandwidth(bdi, ...)	-> [__]wb_update_bandwidth(wb, ...)
  bdi_{max|min}_pause(bdi, ...)		-> wb_{max|min}_pause(wb, ...)
  bdi_dirty_limits(bdi, ...)		-> wb_dirty_limits(wb, ...)

* Init/exits of the relocated fields are moved to bdi_wb_init/exit()
  respectively.  Note that explicit zeroing is dropped in the process
  as wb's are cleared in entirety anyway.

* As there's still only one bdi_writeback per backing_dev_info, all
  uses of bdi->stat[] are mechanically replaced with bdi->wb.stat[]
  introducing no behavior changes.

v2: Typo in description fixed as suggested by Jan.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Current f2fs check the whether the blk device can support discard.
However, the code will cause the discard option cannot be enabled.
Because the clear_opt(sbi, DISCARD) will be invoked forever.

This patch can fix this issue.

Jaegeuk Kim:
 The original patch was intended to disable the discard option when device
 does not support trim command.
 Rather than remaining the buggy patch, let's replace with this patch as
 an integrated one.
Signed-off-by: NChenxi Mao <chenxi.mao2013@gmail.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We don't need to call alloc_page() prior to mempool_alloc(), since the
mempool_alloc() calls alloc_page() internally.
And, if __GFP_WAIT is set, it never fails on page allocation, so let's
give GFP_NOWAIT and handle ENOMEM by writepage().
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In f2fs_gc:                      In f2fs_replace_block:
 - lock_page(sum_page)
  - check_valid_map()            - mutex_lock(sentry_lock)
   - mutex_lock(sentry_lock)     - change_curseg()
                                  - lock_page(sum_page)

This patch fixes the deadlock condition.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Sync with:
  ext4 crypto: clean up error handling in ext4_fname_setup_filename
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes to call f2fs_inherit_context twice for newly created symlink.
The original one is called by f2fs_add_link(), which invokes f2fs_setxattr.
If the second one is called again, f2fs_setxattr is triggered again with same
encryption index.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Encryption policy should only be set to an empty directory through ioctl,
This patch add a judgement condition to verify type of the target inode
to avoid incorrectly configuring for non-directory.

Additionally, remove unneeded inline data conversion since regular or symlink
file should not be processed here.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch add XATTR_CREATE flag in setxattr when setting encryption
context for inode. Without this flag the context could be set more than
once, this should never happen. So, fix it.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For exchange rename, we should check context consistent of encryption
between new_dir and old_inode or old_dir and new_inode. Otherwise
inheritance of parent's encryption context will be broken.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: sync with ext4 approach]
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch tries to clean up code because part code of f2fs_read_end_io
and mpage_end_io are the same, so it's better to merge and reuse them.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

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: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch recovers a broken superblock with the other valid one.
Signed-off-by: Nhujianyang <hujianyang@huawei.com>
[Jaegeuk Kim: reinitialize local variables in f2fs_fill_super for retrial]
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds to check encryption for tmpfile in early stage.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

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: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Add a help function update_meta_page() to update meta page with specified
buffer.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk 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: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk 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: NJaegeuk 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: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes memory leak issue in error path of f2fs_fname_setup_filename().
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk 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: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NJaegeuk 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: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NJaegeuk 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: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NJaegeuk 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: Nhujianyang <hujianyang@huawei.com>
Signed-off-by: NJaegeuk 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: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJaegeuk 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: NArnd Bergmann <arnd@arndb.de>
Fixes: d1f85bd38db19 ("f2fs: avoid value overflow in showing current status")
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch avoids to use a buggy function for now.
It needs to fix them later.
Signed-off-by: NJaegeuk 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: Nhujianyang <hujianyang@huawei.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

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