Merge tag 'f2fs-for-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "We've added two major features: 1) compression level and 2)
  checkpoint_merge, in this round.

  Compression level expands 'compress_algorithm' mount option to accept
  parameter as format of <algorithm>:<level>, by this way, it gives a
  way to allow user to do more specified config on lz4 and zstd
  compression level, then f2fs compression can provide higher compress
  ratio.

  checkpoint_merge creates a kernel daemon and makes it to merge
  concurrent checkpoint requests as much as possible to eliminate
  redundant checkpoint issues. Plus, we can eliminate the sluggish issue
  caused by slow checkpoint operation when the checkpoint is done in a
  process context in a cgroup having low i/o budget and cpu shares.

  Enhancements:
   - add compress level for lz4 and zstd in mount option
   - checkpoint_merge mount option
   - deprecate f2fs_trace_io

  Bug fixes:
   - flush data when enabling checkpoint back
   - handle corner cases of mount options
   - missing ACL update and lock for I_LINKABLE flag
   - attach FIEMAP_EXTENT_MERGED in f2fs_fiemap
   - fix potential deadlock in compression flow
   - fix wrong submit_io condition

  As usual, we've cleaned up many code flows and fixed minor bugs"

* tag 'f2fs-for-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (32 commits)
  Documentation: f2fs: fix typo s/automaic/automatic
  f2fs: give a warning only for readonly partition
  f2fs: don't grab superblock freeze for flush/ckpt thread
  f2fs: add ckpt_thread_ioprio sysfs node
  f2fs: introduce checkpoint_merge mount option
  f2fs: relocate inline conversion from mmap() to mkwrite()
  f2fs: fix a wrong condition in __submit_bio
  f2fs: remove unnecessary initialization in xattr.c
  f2fs: fix to avoid inconsistent quota data
  f2fs: flush data when enabling checkpoint back
  f2fs: deprecate f2fs_trace_io
  f2fs: Remove readahead collision detection
  f2fs: remove unused stat_{inc, dec}_atomic_write
  f2fs: introduce sb_status sysfs node
  f2fs: fix to use per-inode maxbytes
  f2fs: compress: fix potential deadlock
  libfs: unexport generic_ci_d_compare() and generic_ci_d_hash()
  f2fs: fix to set/clear I_LINKABLE under i_lock
  f2fs: fix null page reference in redirty_blocks
  f2fs: clean up post-read processing
  ...

1 files changed, 17 insertions, 1 deletions

diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index dae15c96e659..81c05baa8312 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -247,8 +247,24 @@ checkpoint=%s[:%u[%]]	 Set to "disable" to turn off checkpointing. Set to "enabl
 			 hide up to all remaining free space. The actual space that
 			 would be unusable can be viewed at /sys/fs/f2fs/<disk>/unusable
 			 This space is reclaimed once checkpoint=enable.
+checkpoint_merge	 When checkpoint is enabled, this can be used to create a kernel
+			 daemon and make it to merge concurrent checkpoint requests as
+			 much as possible to eliminate redundant checkpoint issues. Plus,
+			 we can eliminate the sluggish issue caused by slow checkpoint
+			 operation when the checkpoint is done in a process context in
+			 a cgroup having low i/o budget and cpu shares. To make this
+			 do better, we set the default i/o priority of the kernel daemon
+			 to "3", to give one higher priority than other kernel threads.
+			 This is the same way to give a I/O priority to the jbd2
+			 journaling thread of ext4 filesystem.
+nocheckpoint_merge	 Disable checkpoint merge feature.
 compress_algorithm=%s	 Control compress algorithm, currently f2fs supports "lzo",
 			 "lz4", "zstd" and "lzo-rle" algorithm.
+compress_algorithm=%s:%d Control compress algorithm and its compress level, now, only
+			 "lz4" and "zstd" support compress level config.
+			 algorithm	level range
+			 lz4		3 - 16
+			 zstd		1 - 22
 compress_log_size=%u	 Support configuring compress cluster size, the size will
 			 be 4KB * (1 << %u), 16KB is minimum size, also it's
 			 default size.
@@ -831,7 +847,7 @@ This is the default option. f2fs does automatic compression in the writeback of
 compression enabled files.
 
 2) compress_mode=user
-This disables the automaic compression and gives the user discretion of choosing the
+This disables the automatic compression and gives the user discretion of choosing the
 target file and the timing. The user can do manual compression/decompression on the
 compression enabled files using F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE
 ioctls like the below.