f2fs: add an sysfs entry to control the directory level

This patch adds an sysfs entry to control dir_level used by the large directory.

The description of this entry is:

 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.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 8eb06b0a7d2b..803784e1e8ef 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -195,6 +195,13 @@ Files in /sys/fs/f2fs/<devname>
                               cleaning operations. The default value is 4096
                               which covers 8GB block address range.
 
+ 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.
+
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 USAGE
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