Merge tag 'f2fs-for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "In this series, we've implemented transparent compression
  experimentally. It supports LZO and LZ4, but will add more later as we
  investigate in the field more.

  At this point, the feature doesn't expose compressed space to user
  directly in order to guarantee potential data updates later to the
  space. Instead, the main goal is to reduce data writes to flash disk
  as much as possible, resulting in extending disk life time as well as
  relaxing IO congestion.

  Alternatively, we're also considering to add ioctl() to reclaim
  compressed space and show it to user after putting the immutable bit.

  Enhancements:
   - add compression support
   - avoid unnecessary locks in quota ops
   - harden power-cut scenario for zoned block devices
   - use private bio_set to avoid IO congestion
   - replace GC mutex with rwsem to serialize callers

  Bug fixes:
   - fix dentry consistency and memory corruption in rename()'s error case
   - fix wrong swap extent reports
   - fix casefolding bugs
   - change lock coverage to avoid deadlock
   - avoid GFP_KERNEL under f2fs_lock_op

  And, we've cleaned up sysfs entries to prepare no debugfs"

* tag 'f2fs-for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (31 commits)
  f2fs: fix race conditions in ->d_compare() and ->d_hash()
  f2fs: fix dcache lookup of !casefolded directories
  f2fs: Add f2fs stats to sysfs
  f2fs: delete duplicate information on sysfs nodes
  f2fs: change to use rwsem for gc_mutex
  f2fs: update f2fs document regarding to fsync_mode
  f2fs: add a way to turn off ipu bio cache
  f2fs: code cleanup for f2fs_statfs_project()
  f2fs: fix miscounted block limit in f2fs_statfs_project()
  f2fs: show the CP_PAUSE reason in checkpoint traces
  f2fs: fix deadlock allocating bio_post_read_ctx from mempool
  f2fs: remove unneeded check for error allocating bio_post_read_ctx
  f2fs: convert inline_dir early before starting rename
  f2fs: fix memleak of kobject
  f2fs: fix to add swap extent correctly
  f2fs: run fsck when getting bad inode during GC
  f2fs: support data compression
  f2fs: free sysfs kobject
  f2fs: declare nested quota_sem and remove unnecessary sems
  f2fs: don't put new_page twice in f2fs_rename
  ...

1 files changed, 52 insertions, 164 deletions

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 3135b80df6da..4eb3e2ddd00e 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -235,6 +235,17 @@ checkpoint=%s[:%u[%]]     Set to "disable" to turn off checkpointing. Set to "en
                        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.
+compress_algorithm=%s  Control compress algorithm, currently f2fs supports "lzo"
+                       and "lz4" algorithm.
+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.
+compress_extension=%s  Support adding specified extension, so that f2fs can enable
+                       compression on those corresponding files, e.g. if all files
+                       with '.ext' has high compression rate, we can set the '.ext'
+                       on compression extension list and enable compression on
+                       these file by default rather than to enable it via ioctl.
+                       For other files, we can still enable compression via ioctl.
 
 ================================================================================
 DEBUGFS ENTRIES
@@ -259,170 +270,6 @@ The files in each per-device directory are shown in table below.
 
 Files in /sys/fs/f2fs/<devname>
 (see also Documentation/ABI/testing/sysfs-fs-f2fs)
-..............................................................................
- File                         Content
-
- gc_urgent_sleep_time         This parameter controls sleep time for gc_urgent.
-                              500 ms is set by default. See above gc_urgent.
-
- gc_min_sleep_time            This tuning parameter controls the minimum sleep
-                              time for the garbage collection thread. Time is
-                              in milliseconds.
-
- gc_max_sleep_time            This tuning parameter controls the maximum sleep
-                              time for the garbage collection thread. Time is
-                              in milliseconds.
-
- gc_no_gc_sleep_time          This tuning parameter controls the default sleep
-                              time for the garbage collection thread. Time is
-                              in milliseconds.
-
- gc_idle                      This parameter controls the selection of victim
-                              policy for garbage collection. Setting gc_idle = 0
-                              (default) will disable this option. Setting
-                              gc_idle = 1 will select the Cost Benefit approach
-                              & setting gc_idle = 2 will select the greedy approach.
-
- gc_urgent                    This parameter controls triggering background GCs
-                              urgently or not. Setting gc_urgent = 0 [default]
-                              makes back to default behavior, while if it is set
-                              to 1, background thread starts to do GC by given
-                              gc_urgent_sleep_time interval.
-
- reclaim_segments             This parameter controls the number of prefree
-                              segments to be reclaimed. If the number of prefree
-			      segments is larger than the number of segments
-			      in the proportion to the percentage over total
-			      volume size, f2fs tries to conduct checkpoint to
-			      reclaim the prefree segments to free segments.
-			      By default, 5% over total # of segments.
-
- main_blkaddr                 This value gives the first block address of
-			      MAIN area in the partition.
-
- max_small_discards	      This parameter controls the number of discard
-			      commands that consist small blocks less than 2MB.
-			      The candidates to be discarded are cached until
-			      checkpoint is triggered, and issued during the
-			      checkpoint. By default, it is disabled with 0.
-
- discard_granularity	      This parameter controls the granularity of discard
-			      command size. It will issue discard commands iif
-			      the size is larger than given granularity. Its
-			      unit size is 4KB, and 4 (=16KB) is set by default.
-			      The maximum value is 128 (=512KB).
-
- reserved_blocks	      This parameter indicates the number of blocks that
-			      f2fs reserves internally for root.
-
- batched_trim_sections	      This parameter controls the number of sections
-                              to be trimmed out in batch mode when FITRIM
-                              conducts. 32 sections is set by default.
-
- ipu_policy                   This parameter controls the policy of in-place
-                              updates in f2fs. There are five policies:
-                               0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR,
-                               0x04: F2FS_IPU_UTIL,  0x08: F2FS_IPU_SSR_UTIL,
-                               0x10: F2FS_IPU_FSYNC.
-
- min_ipu_util                 This parameter controls the threshold to trigger
-                              in-place-updates. The number indicates percentage
-                              of the filesystem utilization, and used by
-                              F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.
-
- min_fsync_blocks             This parameter controls the threshold to trigger
-                              in-place-updates when F2FS_IPU_FSYNC mode is set.
-			      The number indicates the number of dirty pages
-			      when fsync needs to flush on its call path. If
-			      the number is less than this value, it triggers
-			      in-place-updates.
-
- min_seq_blocks		      This parameter controls the threshold to serialize
-			      write IOs issued by multiple threads in parallel.
-
- min_hot_blocks		      This parameter controls the threshold to allocate
-			      a hot data log for pending data blocks to write.
-
- min_ssr_sections	      This parameter adds the threshold when deciding
-			      SSR block allocation. If this is large, SSR mode
-			      will be enabled early.
-
- ram_thresh                   This parameter controls the memory footprint used
-			      by free nids and cached nat entries. By default,
-			      1 is set, which indicates 10 MB / 1 GB RAM.
-
- ra_nid_pages		      When building free nids, F2FS reads NAT blocks
-			      ahead for speed up. Default is 0.
-
- dirty_nats_ratio	      Given dirty ratio of cached nat entries, F2FS
-			      determines flushing them in background.
-
- max_victim_search	      This parameter controls the number of trials to
-			      find a victim segment when conducting SSR and
-			      cleaning operations. The default value is 4096
-			      which covers 8GB block address range.
-
- migration_granularity	      For large-sized sections, F2FS can stop GC given
-			      this granularity instead of reclaiming entire
-			      section.
-
- dir_level                    This parameter controls the directory level to
-			      support large directory. If a directory has a
-			      number of files, it can reduce the file lookup
-			      latency by increasing this dir_level value.
-			      Otherwise, it needs to decrease this value to
-			      reduce the space overhead. The default value is 0.
-
- cp_interval		      F2FS tries to do checkpoint periodically, 60 secs
-			      by default.
-
- idle_interval		      F2FS detects system is idle, if there's no F2FS
-			      operations during given interval, 5 secs by
-			      default.
-
- discard_idle_interval	      F2FS detects the discard thread is idle, given
-			      time interval. Default is 5 secs.
-
- gc_idle_interval	      F2FS detects the GC thread is idle, given time
-			      interval. Default is 5 secs.
-
- umount_discard_timeout       When unmounting the disk, F2FS waits for finishing
-			      queued discard commands which can take huge time.
-			      This gives time out for it, 5 secs by default.
-
- iostat_enable		      This controls to enable/disable iostat in F2FS.
-
- readdir_ra		      This enables/disabled readahead of inode blocks
-			      in readdir, and default is enabled.
-
- gc_pin_file_thresh	      This indicates how many GC can be failed for the
-			      pinned file. If it exceeds this, F2FS doesn't
-			      guarantee its pinning state. 2048 trials is set
-			      by default.
-
- extension_list		      This enables to change extension_list for hot/cold
-			      files in runtime.
-
- inject_rate		      This controls injection rate of arbitrary faults.
-
- inject_type		      This controls injection type of arbitrary faults.
-
- dirty_segments 	      This shows # of dirty segments.
-
- lifetime_write_kbytes	      This shows # of data written to the disk.
-
- features		      This shows current features enabled on F2FS.
-
- current_reserved_blocks      This shows # of blocks currently reserved.
-
- unusable                     If checkpoint=disable, this shows the number of
-                              blocks that are unusable.
-                              If checkpoint=enable it shows the number of blocks
-                              that would be unusable if checkpoint=disable were
-                              to be set.
-
-encoding 	              This shows the encoding used for casefolding.
-                              If casefolding is not enabled, returns (none)
 
 ================================================================================
 USAGE
@@ -840,3 +687,44 @@ zero or random data, which is useful to the below scenario where:
  4. address = fibmap(fd, offset)
  5. open(blkdev)
  6. write(blkdev, address)
+
+Compression implementation
+--------------------------
+
+- New term named cluster is defined as basic unit of compression, file can
+be divided into multiple clusters logically. One cluster includes 4 << n
+(n >= 0) logical pages, compression size is also cluster size, each of
+cluster can be compressed or not.
+
+- In cluster metadata layout, one special block address is used to indicate
+cluster is compressed one or normal one, for compressed cluster, following
+metadata maps cluster to [1, 4 << n - 1] physical blocks, in where f2fs
+stores data including compress header and compressed data.
+
+- In order to eliminate write amplification during overwrite, F2FS only
+support compression on write-once file, data can be compressed only when
+all logical blocks in file are valid and cluster compress ratio is lower
+than specified threshold.
+
+- To enable compression on regular inode, there are three ways:
+* chattr +c file
+* chattr +c dir; touch dir/file
+* mount w/ -o compress_extension=ext; touch file.ext
+
+Compress metadata layout:
+                             [Dnode Structure]
+             +-----------------------------------------------+
+             | cluster 1 | cluster 2 | ......... | cluster N |
+             +-----------------------------------------------+
+             .           .                       .           .
+       .                       .                .                      .
+  .         Compressed Cluster       .        .        Normal Cluster            .
++----------+---------+---------+---------+  +---------+---------+---------+---------+
+|compr flag| block 1 | block 2 | block 3 |  | block 1 | block 2 | block 3 | block 4 |
++----------+---------+---------+---------+  +---------+---------+---------+---------+
+           .                             .
+         .                                           .
+       .                                                           .
+      +-------------+-------------+----------+----------------------------+
+      | data length | data chksum | reserved |      compressed data       |
+      +-------------+-------------+----------+----------------------------+