This can avoid confusing tracepoint values.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

With below two cases, it will cause NULL pointer dereference when
accessing SM_I(sbi)->fcc_info in f2fs_issue_flush().

a) If kthread_run() fails in f2fs_create_flush_cmd_control(), it will
release SM_I(sbi)->fcc_info,

- mount -o noflush_merge /dev/vda /mnt/f2fs
- mount -o remount,flush_merge /dev/vda /mnt/f2fs  -- kthread_run() fails
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=1 conv=fsync

b) we will never allocate memory for SM_I(sbi)->fcc_info w/ below
testcase,

- mount -o ro /dev/vda /mnt/f2fs
- mount -o rw,remount /dev/vda /mnt/f2fs
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=1 conv=fsync

In order to fix this issue, let change as below:
- fix error path handling in f2fs_create_flush_cmd_control().
- allocate SM_I(sbi)->fcc_info even if readonly is on.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've added two features: F2FS_IOC_START_ATOMIC_REPLACE
  and a per-block age-based extent cache.

  F2FS_IOC_START_ATOMIC_REPLACE is a variant of the previous atomic
  write feature which guarantees a per-file atomicity. It would be more
  efficient than AtomicFile implementation in Android framework.

  The per-block age-based extent cache implements another type of extent
  cache in memory which keeps the per-block age in a file, so that block
  allocator could split the hot and cold data blocks more accurately.

  Enhancements:
   - introduce F2FS_IOC_START_ATOMIC_REPLACE
   - refactor extent_cache to add a new per-block-age-based extent cache support
   - introduce discard_urgent_util, gc_mode, max_ordered_discard sysfs knobs
   - add proc entry to show discard_plist info
   - optimize iteration over sparse directories
   - add barrier mount option

  Bug fixes:
   - avoid victim selection from previous victim section
   - fix to enable compress for newly created file if extension matches
   - set zstd compress level correctly
   - initialize locks early in f2fs_fill_super() to fix bugs reported by syzbot
   - correct i_size change for atomic writes
   - allow to read node block after shutdown
   - allow to set compression for inlined file
   - fix gc mode when gc_urgent_high_remaining is 1
   - should put a page when checking the summary info

  Minor fixes and various clean-ups in GC, discard, debugfs, sysfs, and
  doc"

* tag 'f2fs-for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (63 commits)
  f2fs: reset wait_ms to default if any of the victims have been selected
  f2fs: fix some format WARNING in debug.c and sysfs.c
  f2fs: don't call f2fs_issue_discard_timeout() when discard_cmd_cnt is 0 in f2fs_put_super()
  f2fs: fix iostat parameter for discard
  f2fs: Fix spelling mistake in label: free_bio_enrty_cache -> free_bio_entry_cache
  f2fs: add block_age-based extent cache
  f2fs: allocate the extent_cache by default
  f2fs: refactor extent_cache to support for read and more
  f2fs: remove unnecessary __init_extent_tree
  f2fs: move internal functions into extent_cache.c
  f2fs: specify extent cache for read explicitly
  f2fs: introduce f2fs_is_readonly() for readability
  f2fs: remove F2FS_SET_FEATURE() and F2FS_CLEAR_FEATURE() macro
  f2fs: do some cleanup for f2fs module init
  MAINTAINERS: Add f2fs bug tracker link
  f2fs: remove the unused flush argument to change_curseg
  f2fs: open code allocate_segment_by_default
  f2fs: remove struct segment_allocation default_salloc_ops
  f2fs: introduce discard_urgent_util sysfs node
  f2fs: define MIN_DISCARD_GRANULARITY macro
  ...

No need to call f2fs_issue_discard_timeout() in f2fs_put_super,
when no discard command requires issue. Since the caller of
f2fs_issue_discard_timeout() usually judges the number of discard
commands before using it. Let's move this logic to
f2fs_issue_discard_timeout().

By the way, use f2fs_realtime_discard_enable to simplify the code.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Just like other data we count uses the number of bytes as the basic unit,
but discard uses the number of cmds as the statistical unit. In fact the
discard command contains the number of blocks, so let's change to the
number of bytes as the base unit.

Fixes: b0af6d491a6b ("f2fs: add app/fs io stat")
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch introduces a runtime hot/cold data separation method
for f2fs, in order to improve the accuracy for data temperature
classification, reduce the garbage collection overhead after
long-term data updates.

Enhanced hot/cold data separation can record data block update
frequency as "age" of the extent per inode, and take use of the age
info to indicate better temperature type for data block allocation:
 - It records total data blocks allocated since mount;
 - When file extent has been updated, it calculate the count of data
blocks allocated since last update as the age of the extent;
 - Before the data block allocated, it searches for the age info and
chooses the suitable segment for allocation.

Test and result:
 - Prepare: create about 30000 files
  * 3% for cold files (with cold file extension like .apk, from 3M to 10M)
  * 50% for warm files (with random file extension like .FcDxq, from 1K
to 4M)
  * 47% for hot files (with hot file extension like .db, from 1K to 256K)
 - create(5%)/random update(90%)/delete(5%) the files
  * total write amount is about 70G
  * fsync will be called for .db files, and buffered write will be used
for other files

The storage of test device is large enough(128G) so that it will not
switch to SSR mode during the test.

Benefit: dirty segment count increment reduce about 14%
 - before: Dirty +21110
 - after:  Dirty +18286

Signed-off-by: qixiaoyu1 <qixiaoyu1@xiaomi.com>
Signed-off-by: xiongping1 <xiongping1@xiaomi.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch prepares extent_cache to be ready for addition.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Let's descrbie it's read extent cache.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

allocate_segment_by_default has just two callers, which use very
different code pathes inside it based on the force paramter.  Just
open code the logic in the two callers using a new helper to decided
if a new segment should be allocated.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>