Thread A			Thread B
- f2fs_release_file
 - clear_inode_flag(FI_VOLATILE_FILE)
				- wb_writeback
				 - writeback_sb_inodes
				  - __writeback_single_inode
				   - do_writepages
				    - f2fs_write_data_pages
				     - __write_data_page
				     all volatile file's pages
				     are writebacked to storage
 - set_inode_flag(FI_DROP_CACHE)
 - filemap_fdatawrite

There is a hole that mm can flush all dirty pages of volatile file as
inode is not tagged with both FI_VOLATILE_FILE and FI_DROP_CACHE flags,
we should never writeback the page #0 and also it's unneeded to writeback
other pages.

This patch adjusts to relocate clear_inode_flag(FI_VOLATILE_FILE), so that
FI_VOLATILE_FILE flag can be remained before all dirty pages were dropped
to avoid issue.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Although mixed sync/async IOs can have continuous LBA, as they have
different IO priority, block IO scheduler will add them into different
queues and commit them separately, result in splited IOs which causes
wrose performance.

This patch gives high priority to synchronous IO of nodes, means that
once synchronous flow starts, it can interrupt asynchronous writeback
flow of system flusher, so more big IOs can be expected.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We should never falsify wbc->sync_mode passed from mm, otherwise
mm can trigger writeback with wrong IO priority.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If we change system time to the past, get_mtime() will return a
overflowed time, and SIT_I(sbi)->max_mtime will be udpated
incorrectly, this patch fixes the two issues.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

clean up checkpatch error:
ERROR: space required after that ':'
ERROR: space required after that ','
Signed-off-by: Nyoungjun yoo <youngjun.willow@gmail.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

clean up checkpatch warning:
WARNING: Missing a blank line after declarations
Signed-off-by: Nyoungjun yoo <youngjun.willow@gmail.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

clean up checkpatch warning:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
Signed-off-by: Nyoungjun yoo <youngjun.willow@gmail.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

As Ted reported:

"Hi, I was looking at f2fs's sources recently, and I noticed that there
is a very large number of non-static symbols which don't have a f2fs
prefix.  There's well over a hundred (see attached below).

As one example, in fs/f2fs/dir.c there is:

unsigned char get_de_type(struct f2fs_dir_entry *de)

This function is clearly only useful for f2fs, but it has a generic
name.  This means that if any other file system tries to have the same
symbol name, there will be a symbol conflict and the kernel would not
successfully build.  It also means that when someone is looking f2fs
sources, it's not at all obvious whether a function such as
read_data_page(), invalidate_blocks(), is a generic kernel function
found in the fs, mm, or block layers, or a f2fs specific function.

You might want to fix this at some point.  Hopefully Kent's bcachefs
isn't similarly using genericly named functions, since that might
cause conflicts with f2fs's functions --- but just as this would be a
problem that we would rightly insist that Kent fix, this is something
that we should have rightly insisted that f2fs should have fixed
before it was integrated into the mainline kernel.

acquire_orphan_inode
add_ino_entry
add_orphan_inode
allocate_data_block
allocate_new_segments
alloc_nid
alloc_nid_done
alloc_nid_failed
available_free_memory
...."

This patch adds "f2fs_" prefix for all non-static symbols in order to:
a) avoid conflict with other kernel generic symbols;
b) to indicate the function is f2fs specific one instead of generic
one;
Reported-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Configure io_bits with 2 and enable LFS mode, generic/017 reports below dmesg:

BUG: unable to handle kernel NULL pointer dereference at 00000039
*pdpt = 000000002fcb2001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: crc32_generic zram f2fs(O) bnep rfcomm bluetooth ecdh_generic snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi pcbc snd_seq joydev aesni_intel aes_i586 snd_seq_device snd_timer crypto_simd cryptd snd soundcore i2c_piix4 serio_raw mac_hid video parport_pc ppdev lp parport hid_generic usbhid psmouse hid e1000
CPU: 2 PID: 20779 Comm: xfs_io Tainted: G           O      4.17.0-rc2 #38
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
EIP: is_checkpointed_data+0x84/0xd0 [f2fs]
EFLAGS: 00010207 CPU: 2
EAX: 00000000 EBX: f5cd7000 ECX: fffffe32 EDX: 00000039
ESI: 000001cd EDI: ec95fb6c EBP: e264bd80 ESP: e264bd6c
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 80050033 CR2: 00000039 CR3: 2fe55660 CR4: 000406f0
Call Trace:
 __exchange_data_block+0xb3f/0x1000 [f2fs]
 f2fs_fallocate+0xab9/0x16b0 [f2fs]
 vfs_fallocate+0x17c/0x2d0
 ksys_fallocate+0x42/0x70
 sys_fallocate+0x31/0x40
 do_fast_syscall_32+0xaa/0x22c
 entry_SYSENTER_32+0x4c/0x7b
EIP: 0xb7f98c51
EFLAGS: 00000293 CPU: 2
EAX: ffffffda EBX: 00000003 ECX: 00000008 EDX: 01001000
ESI: 00000000 EDI: 00001000 EBP: 00000000 ESP: bfc0357c
 DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
Code: 00 00 d3 e8 8b 4d ec 2b 02 8b 55 f0 6b c0 1c 03 41 70 29 d6 8b 93 d0 06 00 00 8b 40 0c 83 ea 01 21 d6 89 f2 89 f1 c1 ea 03 f7 d1 <0f> be 14 10 83 e1 07 b8 01 00 00 00 d3 e0 85 c2 89 f8 0f 95 c3
EIP: is_checkpointed_data+0x84/0xd0 [f2fs] SS:ESP: 0068:e264bd6c
CR2: 0000000000000039
---[ end trace 9a4d4087cce6080a ]---

This is because in recovery flow of __exchange_data_block, we didn't pass olen to
__roll_back_blkaddrs, instead we passed len, which indicates wrong array size, result
in copying random block address into dnode page.

Later, once that random block address was accessed by is_checkpointed_data, it can
cause NULL pointer dereference.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Configure io_bits with 2 and enable LFS mode, generic/013 reports below dmesg:

BUG: unable to handle kernel NULL pointer dereference at 00000104
*pdpt = 0000000029b7b001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP
Modules linked in: crc32_generic zram f2fs(O) rfcomm bnep bluetooth ecdh_generic snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq pcbc joydev snd_seq_device aesni_intel snd_timer aes_i586 snd crypto_simd cryptd soundcore i2c_piix4 serio_raw mac_hid video parport_pc ppdev lp parport hid_generic psmouse usbhid hid e1000
CPU: 0 PID: 11161 Comm: fsstress Tainted: G           O      4.17.0-rc2 #38
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
EIP: f2fs_submit_page_write+0x28d/0x550 [f2fs]
EFLAGS: 00010206 CPU: 0
EAX: e863dcd8 EBX: 00000000 ECX: 00000100 EDX: 00000200
ESI: e863dcf4 EDI: f6f82768 EBP: e863dbb0 ESP: e863db74
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 80050033 CR2: 00000104 CR3: 29a62020 CR4: 000406f0
Call Trace:
 do_write_page+0x6f/0xc0 [f2fs]
 write_data_page+0x4a/0xd0 [f2fs]
 do_write_data_page+0x327/0x630 [f2fs]
 __write_data_page+0x34b/0x820 [f2fs]
 __f2fs_write_data_pages+0x42d/0x8c0 [f2fs]
 f2fs_write_data_pages+0x27/0x30 [f2fs]
 do_writepages+0x1a/0x70
 __filemap_fdatawrite_range+0x94/0xd0
 filemap_write_and_wait_range+0x3d/0xa0
 __generic_file_write_iter+0x11a/0x1f0
 f2fs_file_write_iter+0xdd/0x3b0 [f2fs]
 __vfs_write+0xd2/0x150
 vfs_write+0x9b/0x190
 ksys_write+0x45/0x90
 sys_write+0x16/0x20
 do_fast_syscall_32+0xaa/0x22c
 entry_SYSENTER_32+0x4c/0x7b
EIP: 0xb7fc8c51
EFLAGS: 00000246 CPU: 0
EAX: ffffffda EBX: 00000003 ECX: 09cde000 EDX: 00001000
ESI: 00000003 EDI: 00001000 EBP: 00000000 ESP: bfbded38
 DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
Code: e8 f9 77 34 c9 8b 45 e0 8b 80 b8 00 00 00 39 45 d8 0f 84 bb 02 00 00 8b 45 e0 8b 80 b8 00 00 00 8d 50 d8 8b 08 89 55 f0 8b 50 04 <89> 51 04 89 0a c7 00 00 01 00 00 c7 40 04 00 02 00 00 8b 45 dc
EIP: f2fs_submit_page_write+0x28d/0x550 [f2fs] SS:ESP: 0068:e863db74
CR2: 0000000000000104
---[ end trace 4cac79c0d1305ee6 ]---

allocate_data_block will submit all sequential pending IOs sorted by a
FIFO list, If we failed to submit other user's IO due to unaligned write,
we will retry to allocate new block address for current IO, then it will
initialize fio.list again, if fio was in the list before, it can break
FIFO list, result in above panic.

Thread A			Thread B
- do_write_page
 - allocate_data_block
  - list_add_tail
  : fioA cached in FIFO list.
				- do_write_page
				 - allocate_data_block
				  - list_add_tail
				  : fioB cached in FIFO list.
				 - f2fs_submit_page_write
				 : fail to submit IO
				 - allocate_data_block
				  - INIT_LIST_HEAD
 - f2fs_submit_page_write
  - list_del  <-- NULL pointer dereference

This patch adds fio.retry parameter to indicate failure status for each
IO, and avoid bailing out if there is still pending IO in FIFO list for
fixing.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The following patch disables loading of f2fs module on architectures
which have PAGE_SIZE > 4096 , since it is impossible to mount f2fs on
such architectures , log messages are:

mount: /mnt: wrong fs type, bad option, bad superblock on
/dev/vdiskb1, missing codepage or helper program, or other error.
/dev/vdiskb1: F2FS filesystem,
UUID=1d8b9ca4-2389-4910-af3b-10998969f09c, volume name ""

May 15 18:03:13 ttip kernel: F2FS-fs (vdiskb1): Invalid
page_cache_size (8192), supports only 4KB
May 15 18:03:13 ttip kernel: F2FS-fs (vdiskb1): Can't find valid F2FS
filesystem in 1th superblock
May 15 18:03:13 ttip kernel: F2FS-fs (vdiskb1): Invalid
page_cache_size (8192), supports only 4KB
May 15 18:03:13 ttip kernel: F2FS-fs (vdiskb1): Can't find valid F2FS
filesystem in 2th superblock
May 15 18:03:13 ttip kernel: F2FS-fs (vdiskb1): Invalid
page_cache_size (8192), supports only 4KB

which was introduced by git commit 5c9b4692

tested on git kernel 4.17.0-rc6-00309-gec30dcf7

with patch applied:

modprobe: ERROR: could not insert 'f2fs': Invalid argument
May 28 01:40:28 v215 kernel: F2FS not supported on PAGE_SIZE(8192) != 4096
Signed-off-by: NAnatoly Pugachev <matorola@gmail.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes error path of move_data_page:
- clear cold data flag if it fails to write page.
- redirty page for non-ENOMEM case.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

As description in commit "f2fs: don't drop any page on f2fs_cp_error()
case":

"We still provide readdir() after shtudown, so we should keep pages to
avoid additional IOs."

In order to provider lastest directory structure, let's keep dentry
pages in cache after fs shutdown.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Thread A			Thread B
- f2fs_remount
 - stop_gc_thread
				- f2fs_sbi_store
   sbi->gc_thread = NULL;
				  access sbi->gc_thread->gc_*

Previously, we allocate memory for sbi->gc_thread based on background
gc thread mount option, the memory can be released if we turn off
that mount option, but still there are several places access gc_thread
pointer without considering race condition, result in NULL point
dereference.

In order to fix this issue, use sb->s_umount to exclude those operations.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Introduce clear_radix_tree_dirty_tag to include common codes for cleanup.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

- f2fs_fill_super
 - recover_fsync_data
  - recover_data
   - del_fsync_inode
    - iput
     - iput_final
      - write_inode_now
       - f2fs_write_inode
        - f2fs_balance_fs
         - f2fs_balance_fs_bg
          - sync_dirty_inodes

With data_flush mount option, during recovery, in order to avoid entering
above writeback flow, let's detect recovery status and do skip in
f2fs_balance_fs_bg.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NYunlei He <heyunlei@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If SBI_NEED_FSCK is set, discard_wake will never be cleared. As a
result, the condition of wait_event_interruptible_timeout() is always
true, which gets discard thread run too frequently.
Signed-off-by: NSheng Yong <shengyong1@huawei.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch modify discard thread wait policy as below:
	issued       io_interrupted     wait time(ms)
1.        8                 0               50
2.      (0,8)               1               50
3.        0                 1              500 (dev is busy)
4.        0                 0            60000 (no candidates)
Signed-off-by: NYunlei He <heyunlei@huawei.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

f2fs doesn't allow abuse on atomic write class interface, so except
limiting in-mem pages' total memory usage capacity, we need to limit
atomic-write usage as well when filesystem is seriously fragmented,
otherwise we may run into infinite loop during foreground GC because
target blocks in victim segment are belong to atomic opened file for
long time.

Now, we will detect failure due to atomic write in foreground GC, if
the count exceeds threshold, we will drop all atomic written data in
cache, by this, I expect it can keep our system running safely to
prevent Dos attack.

In addition, his patch adds to show GC skip information in debugfs,
now it just shows count of skipped caused by atomic write.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This is to avoid sbi->gc_thread pointer access.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For non-migration IO, we will keep order of data/node blocks' submitting
as allocation sequence by sorting IOs in per log io_list list, but for
migration IO, it could be out-of-order.

In LFS mode, we should keep all IOs including migration IO be ordered,
so that this patch fixes to add an additional lock to keep submitting
order.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

After revoking atomic write, related LBA can be reused by others, so we
need to wait page writeback before reusing the LBA, in order to avoid
interference between old atomic written in-flight IO and new IO.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

f2fs_ioc_shutdown() ioctl gets stuck in the below path
when issued with F2FS_GOING_DOWN_FULLSYNC option.

__switch_to+0x90/0xc4
percpu_down_write+0x8c/0xc0
freeze_super+0xec/0x1e4
freeze_bdev+0xc4/0xcc
f2fs_ioctl+0xc0c/0x1ce0
f2fs_compat_ioctl+0x98/0x1f0
Signed-off-by: NSahitya Tummala <stummala@codeaurora.org>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch changes to detect synchronous writeback more earlier before,
in order to avoid unnecessary page writeback before exiting asynchronous
writeback.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

- rename is_valid_blkaddr() to is_valid_meta_blkaddr() for readability.
- introduce is_valid_blkaddr() for cleanup.

No logic change in this patch.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Since sit_i.min_mtime's type is unsigned long long, so we should
initialize it with max value of the type ULLONG_MAX instead of
LLONG_MAX.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

1. thread A: commit_inmem_pages submit data into block layer, but
haven't waited it writeback.
2. thread A: commit_inmem_pages update related node.
3. thread B: do checkpoint, flush all nodes to disk.
4. SPOR

Then, atomic file becomes corrupted since nodes is flushed before data.

This patch fixes to treat atomic page as checkpoint guaranteed one,
then in checkpoint, we can make sure all atomic page can be writebacked
with metadata of atomic file.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

i_current_depth is used only for directory inode, but its space is
shared with i_gc_failures field used for regular inode, in order to
avoid affecting i_gc_failures' value, this patch fixes to initialize
the union's fields according to inode type.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For extreme case:
10 section, op = 10%, no_fggc_threshold = 90%
All section usage: 85% 85% 85% 85% 90% 90% 95% 95% 95% 95%

During foreground GC, if we skip select dirty section whose usage
is larger than no_fggc_threshold, we can only recycle 80% invalid
space from four 85% usage sections and two 90% usage sections,
result in encountering out-of-space issue.

This reverts commit e93b9865 to
fix this issue, besides, we keep the logic that we scan all dirty
section when searching a victim, so that GC can select victim with
least valid blocks.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We still provide readdir() after shtudown, so we should keep pages to avoid
additional IOs.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Trivial fix to spelling mistake in extension list text
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In order to avoid the below overflow issue, we should have checked the
boundaries in superblock before reaching out to allocation. As Linus suggested,
the right place should be sanity_check_raw_super().

Dr Silvio Cesare of InfoSect reported:

There are integer overflows with using the cp_payload superblock field in the
f2fs filesystem potentially leading to memory corruption.

include/linux/f2fs_fs.h

struct f2fs_super_block {
...
        __le32 cp_payload;

fs/f2fs/f2fs.h

typedef u32 block_t;    /*
                         * should not change u32, since it is the on-disk block
                         * address format, __le32.
                         */
...

static inline block_t __cp_payload(struct f2fs_sb_info *sbi)
{
        return le32_to_cpu(F2FS_RAW_SUPER(sbi)->cp_payload);
}

fs/f2fs/checkpoint.c

        block_t start_blk, orphan_blocks, i, j;
...
        start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
        orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);

+++ integer overflows

...
        unsigned int cp_blks = 1 + __cp_payload(sbi);
...
        sbi->ckpt = kzalloc(cp_blks * blk_size, GFP_KERNEL);

+++ integer overflow leading to incorrect heap allocation.

        int cp_payload_blks = __cp_payload(sbi);
...
        ckpt->cp_pack_start_sum = cpu_to_le32(1 + cp_payload_blks +
                        orphan_blocks);

+++ sign bug and integer overflow

...
        for (i = 1; i < 1 + cp_payload_blks; i++)

+++ integer overflow

...

      sbi->max_orphans = (sbi->blocks_per_seg - F2FS_CP_PACKS -
                        NR_CURSEG_TYPE - __cp_payload(sbi)) *
                                F2FS_ORPHANS_PER_BLOCK;

+++ integer overflow
Reported-by: NGreg KH <greg@kroah.com>
Reported-by: NSilvio Cesare <silvio.cesare@gmail.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Volatile file's data will be updated oftenly, so it'd better to place
its data into hot data segment.

In addition, for atomic file, we change to check FI_ATOMIC_FILE instead
of FI_HOT_DATA to make code readability better.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Introduce release_discard_addr() to include common codes for cleanup.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
[Fengguang Wu: declare static function, reported by kbuild test robot]
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In build_sit_entries(), if valid_blocks in SIT block is smaller than
valid_blocks in journal, for below calculation:

sbi->discard_blks += old_valid_blocks - se->valid_blocks;

There will be two times potential overflow:
- old_valid_blocks - se->valid_blocks will overflow, and be a very
large number.
- sbi->discard_blks += result will overflow again, comes out a correct
result accidently.

Anyway, it should be fixed.

Fixes: d600af23 ("f2fs: avoid unneeded loop in build_sit_entries")
Fixes: 1f43e2ad ("f2fs: introduce CP_TRIMMED_FLAG to avoid unneeded discard")
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

RW semphore dio_rwsem in struct f2fs_inode_info is introduced to avoid
race between dio and data gc, but now, it is more wildly used to avoid
foreground operation vs data gc. So rename it to i_gc_rwsem to improve
its readability.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch move mnt_want_write_file after range check,
it's needless to check arguments with it.
Signed-off-by: NYunlei He <heyunlei@huawei.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fix missing clear FI_NO_PREALLOC in some error case
Signed-off-by: NYunlei He <heyunlei@huawei.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>