f2fs: delete duplicate information on sysfs nodes

This patch merges the sysfs node documentation present in
Documentation/filesystems/f2fs.txt and
Documentation/ABI/testing/sysfs-fs-f2fs
and deletes the duplicate information from
Documentation/filesystems/f2fs.txt. This is to prevent having to update
both files when a new sysfs node is added for f2fs.
The patch also makes minor formatting changes to
Documentation/ABI/testing/sysfs-fs-f2fs.

Signed-off-by: Hridya Valsaraju <hridya@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 120 insertions, 113 deletions

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index aedeae1e8ec1..7cdaed02981a 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -1,37 +1,40 @@
 What:		/sys/fs/f2fs/<disk>/gc_max_sleep_time
 Date:		July 2013
 Contact:	"Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
-		 Controls the maximun sleep time for gc_thread. Time
-		 is in milliseconds.
+Description:	Controls the maximum sleep time for gc_thread. Time
+		is in milliseconds.
 
 What:		/sys/fs/f2fs/<disk>/gc_min_sleep_time
 Date:		July 2013
 Contact:	"Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
-		 Controls the minimum sleep time for gc_thread. Time
-		 is in milliseconds.
+Description:	Controls the minimum sleep time for gc_thread. Time
+		is in milliseconds.
 
 What:		/sys/fs/f2fs/<disk>/gc_no_gc_sleep_time
 Date:		July 2013
 Contact:	"Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
-		 Controls the default sleep time for gc_thread. Time
-		 is in milliseconds.
+Description:	Controls the default sleep time for gc_thread. Time
+		is in milliseconds.
 
 What:		/sys/fs/f2fs/<disk>/gc_idle
 Date:		July 2013
 Contact:	"Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
-		 Controls the victim selection policy for garbage collection.
+Description:	Controls the victim selection 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.
 
 What:		/sys/fs/f2fs/<disk>/reclaim_segments
 Date:		October 2013
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the issue rate of segment discard commands.
-
-What:		/sys/fs/f2fs/<disk>/max_blkaddr
+Description:	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.
+
+What:		/sys/fs/f2fs/<disk>/main_blkaddr
 Date:		November 2019
 Contact:	"Ramon Pantin" <pantin@google.com>
 Description:
@@ -40,227 +43,231 @@ Description:
 What:		/sys/fs/f2fs/<disk>/ipu_policy
 Date:		November 2013
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the in-place-update policy.
+Description:	Controls the in-place-update policy.
+		updates in f2fs. User can set:
+		0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR,
+		0x04: F2FS_IPU_UTIL,  0x08: F2FS_IPU_SSR_UTIL,
+		0x10: F2FS_IPU_FSYNC, 0x20: F2FS_IPU_ASYNC,
+		0x40: F2FS_IPU_NOCACHE.
+		Refer segment.h for details.
 
 What:		/sys/fs/f2fs/<disk>/min_ipu_util
 Date:		November 2013
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the FS utilization condition for the in-place-update
-		 policies.
+Description:	Controls the FS utilization condition for the in-place-update
+		policies. It is used by F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.
 
 What:		/sys/fs/f2fs/<disk>/min_fsync_blocks
 Date:		September 2014
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls the dirty page count condition for the in-place-update
-		 policies.
+Description:	Controls the dirty page count condition for the in-place-update
+		policies.
 
 What:		/sys/fs/f2fs/<disk>/min_seq_blocks
 Date:		August 2018
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls the dirty page count condition for batched sequential
-		 writes in ->writepages.
-
+Description:	Controls the dirty page count condition for batched sequential
+		writes in writepages.
 
 What:		/sys/fs/f2fs/<disk>/min_hot_blocks
 Date:		March 2017
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls the dirty page count condition for redefining hot data.
+Description:	Controls the dirty page count condition for redefining hot data.
 
 What:		/sys/fs/f2fs/<disk>/min_ssr_sections
 Date:		October 2017
 Contact:	"Chao Yu" <yuchao0@huawei.com>
-Description:
-		 Controls the fee section threshold to trigger SSR allocation.
+Description:	Controls the free section threshold to trigger SSR allocation.
+		If this is large, SSR mode will be enabled early.
 
 What:		/sys/fs/f2fs/<disk>/max_small_discards
 Date:		November 2013
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the issue rate of small discard commands.
+Description:	Controls the issue rate of discard commands that consist of 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.
 
-What:          /sys/fs/f2fs/<disk>/discard_granularity
-Date:          July 2017
-Contact:       "Chao Yu" <yuchao0@huawei.com>
-Description:
-		Controls discard granularity of inner discard thread, inner thread
+What:		/sys/fs/f2fs/<disk>/discard_granularity
+Date:		July 2017
+Contact:	"Chao Yu" <yuchao0@huawei.com>
+Description:	Controls discard granularity of inner discard thread. Inner thread
 		will not issue discards with size that is smaller than granularity.
-		The unit size is one block, now only support configuring in range
-		of [1, 512].
+		The unit size is one block(4KB), now only support configuring
+		in range of [1, 512]. Default value is 4(=16KB).
 
-What:          /sys/fs/f2fs/<disk>/umount_discard_timeout
-Date:          January 2019
-Contact:       "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		Set timeout to issue discard commands during umount.
-		Default: 5 secs
+What:		/sys/fs/f2fs/<disk>/umount_discard_timeout
+Date:		January 2019
+Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
+Description:	Set timeout to issue discard commands during umount.
+	        Default: 5 secs
 
 What:		/sys/fs/f2fs/<disk>/max_victim_search
 Date:		January 2014
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the number of trials to find a victim segment.
+Description:	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.
 
 What:		/sys/fs/f2fs/<disk>/migration_granularity
 Date:		October 2018
 Contact:	"Chao Yu" <yuchao0@huawei.com>
-Description:
-		 Controls migration granularity of garbage collection on large
-		 section, it can let GC move partial segment{s} of one section
-		 in one GC cycle, so that dispersing heavy overhead GC to
-		 multiple lightweight one.
+Description:	Controls migration granularity of garbage collection on large
+		section, it can let GC move partial segment{s} of one section
+		in one GC cycle, so that dispersing heavy overhead GC to
+		multiple lightweight one.
 
 What:		/sys/fs/f2fs/<disk>/dir_level
 Date:		March 2014
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the directory level for large directory.
+Description:	Controls the directory level for 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.
 
 What:		/sys/fs/f2fs/<disk>/ram_thresh
 Date:		March 2014
 Contact:	"Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
-		 Controls the memory footprint used by f2fs.
+Description:	Controls the memory footprint used by free nids and cached
+		nat entries. By default, 1 is set, which indicates
+		10 MB / 1 GB RAM.
 
 What:		/sys/fs/f2fs/<disk>/batched_trim_sections
 Date:		February 2015
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls the trimming rate in batch mode.
-		 <deprecated>
+Description:	Controls the trimming rate in batch mode.
+		<deprecated>
 
 What:		/sys/fs/f2fs/<disk>/cp_interval
 Date:		October 2015
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls the checkpoint timing.
+Description:	Controls the checkpoint timing, set to 60 seconds by default.
 
 What:		/sys/fs/f2fs/<disk>/idle_interval
 Date:		January 2016
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls the idle timing for all paths other than
-		 discard and gc path.
+Description:	Controls the idle timing of system, if there is no FS operation
+		during given interval.
+		Set to 5 seconds by default.
 
 What:		/sys/fs/f2fs/<disk>/discard_idle_interval
 Date:		September 2018
 Contact:	"Chao Yu" <yuchao0@huawei.com>
 Contact:	"Sahitya Tummala" <stummala@codeaurora.org>
-Description:
-		 Controls the idle timing for discard path.
+Description:	Controls the idle timing of discard thread given
+		this time interval.
+		Default is 5 secs.
 
 What:		/sys/fs/f2fs/<disk>/gc_idle_interval
 Date:		September 2018
 Contact:	"Chao Yu" <yuchao0@huawei.com>
 Contact:	"Sahitya Tummala" <stummala@codeaurora.org>
-Description:
-		 Controls the idle timing for gc path.
+Description:    Controls the idle timing for gc path. Set to 5 seconds by default.
 
 What:		/sys/fs/f2fs/<disk>/iostat_enable
 Date:		August 2017
 Contact:	"Chao Yu" <yuchao0@huawei.com>
-Description:
-		 Controls to enable/disable IO stat.
+Description:	Controls to enable/disable IO stat.
 
 What:		/sys/fs/f2fs/<disk>/ra_nid_pages
 Date:		October 2015
 Contact:	"Chao Yu" <chao2.yu@samsung.com>
-Description:
-		 Controls the count of nid pages to be readaheaded.
+Description:	Controls the count of nid pages to be readaheaded.
+		When building free nids, F2FS reads NAT blocks ahead for
+		speed up. Default is 0.
 
 What:		/sys/fs/f2fs/<disk>/dirty_nats_ratio
 Date:		January 2016
 Contact:	"Chao Yu" <chao2.yu@samsung.com>
-Description:
-		 Controls dirty nat entries ratio threshold, if current
-		 ratio exceeds configured threshold, checkpoint will
-		 be triggered for flushing dirty nat entries.
+Description:	Controls dirty nat entries ratio threshold, if current
+		ratio exceeds configured threshold, checkpoint will
+		be triggered for flushing dirty nat entries.
 
 What:		/sys/fs/f2fs/<disk>/lifetime_write_kbytes
 Date:		January 2016
 Contact:	"Shuoran Liu" <liushuoran@huawei.com>
-Description:
-		 Shows total written kbytes issued to disk.
+Description:	Shows total written kbytes issued to disk.
 
 What:		/sys/fs/f2fs/<disk>/features
 Date:		July 2017
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Shows all enabled features in current device.
+Description:	Shows all enabled features in current device.
 
 What:		/sys/fs/f2fs/<disk>/inject_rate
 Date:		May 2016
 Contact:	"Sheng Yong" <shengyong1@huawei.com>
-Description:
-		 Controls the injection rate.
+Description:	Controls the injection rate of arbitrary faults.
 
 What:		/sys/fs/f2fs/<disk>/inject_type
 Date:		May 2016
 Contact:	"Sheng Yong" <shengyong1@huawei.com>
-Description:
-		 Controls the injection type.
+Description:	Controls the injection type of arbitrary faults.
+
+What:		/sys/fs/f2fs/<disk>/dirty_segments
+Date:		October 2017
+Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
+Description:	Shows the number of dirty segments.
 
 What:		/sys/fs/f2fs/<disk>/reserved_blocks
 Date:		June 2017
 Contact:	"Chao Yu" <yuchao0@huawei.com>
-Description:
-		 Controls target reserved blocks in system, the threshold
-		 is soft, it could exceed current available user space.
+Description:	Controls target reserved blocks in system, the threshold
+		is soft, it could exceed current available user space.
 
 What:		/sys/fs/f2fs/<disk>/current_reserved_blocks
 Date:		October 2017
 Contact:	"Yunlong Song" <yunlong.song@huawei.com>
 Contact:	"Chao Yu" <yuchao0@huawei.com>
-Description:
-		 Shows current reserved blocks in system, it may be temporarily
-		 smaller than target_reserved_blocks, but will gradually
-		 increase to target_reserved_blocks when more free blocks are
-		 freed by user later.
+Description:	Shows current reserved blocks in system, it may be temporarily
+		smaller than target_reserved_blocks, but will gradually
+		increase to target_reserved_blocks when more free blocks are
+		freed by user later.
 
 What:		/sys/fs/f2fs/<disk>/gc_urgent
 Date:		August 2017
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Do background GC agressively
+Description:	Do background GC agressively when set. When gc_urgent = 1,
+		background thread starts to do GC by given gc_urgent_sleep_time
+		interval. It is set to 0 by default.
 
 What:		/sys/fs/f2fs/<disk>/gc_urgent_sleep_time
 Date:		August 2017
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
-		 Controls sleep time of GC urgent mode
+Description:	Controls sleep time of GC urgent mode. Set to 500ms by default.
 
 What:		/sys/fs/f2fs/<disk>/readdir_ra
 Date:		November 2017
 Contact:	"Sheng Yong" <shengyong1@huawei.com>
-Description:
-		 Controls readahead inode block in readdir.
+Description:	Controls readahead inode block in readdir. Enabled by default.
+
+What:		/sys/fs/f2fs/<disk>/gc_pin_file_thresh
+Date:		January 2018
+Contact:	Jaegeuk Kim <jaegeuk@kernel.org>
+Description:	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.
 
 What:		/sys/fs/f2fs/<disk>/extension_list
 Date:		Feburary 2018
 Contact:	"Chao Yu" <yuchao0@huawei.com>
-Description:
-		 Used to control configure extension list:
-		 - Query: cat /sys/fs/f2fs/<disk>/extension_list
-		 - Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list
-		 - Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list
-		 - [h] means add/del hot file extension
-		 - [c] means add/del cold file extension
+Description:	Used to control configure extension list:
+		- Query: cat /sys/fs/f2fs/<disk>/extension_list
+		- Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list
+		- Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list
+		- [h] means add/del hot file extension
+		- [c] means add/del cold file extension
 
 What:		/sys/fs/f2fs/<disk>/unusable
 Date		April 2019
 Contact:	"Daniel Rosenberg" <drosen@google.com>
-Description:
-		If checkpoint=disable, it displays the number of blocks that are unusable.
-                If checkpoint=enable it displays the enumber of blocks that would be unusable
-                if checkpoint=disable were to be set.
+Description:	If checkpoint=disable, it displays the number of blocks that
+		are unusable.
+		If checkpoint=enable it displays the enumber of blocks that
+		would be unusable if checkpoint=disable were to be set.
 
 What:		/sys/fs/f2fs/<disk>/encoding
 Date		July 2019
 Contact:	"Daniel Rosenberg" <drosen@google.com>
-Description:
-		Displays name and version of the encoding set for the filesystem.
-                If no encoding is set, displays (none)
+Description:	Displays name and version of the encoding set for the filesystem.
+		If no encoding is set, displays (none)