f2fs: give an option to enable in-place-updates during fsync to users

If user wrote F2FS_IPU_FSYNC:4 in /sys/fs/f2fs/ipu_policy, f2fs_sync_file
only starts to try in-place-updates.
And, if the number of dirty pages is over /sys/fs/f2fs/min_fsync_blocks, it
keeps out-of-order manner. Otherwise, it triggers in-place-updates.

This may be used by storage showing very high random write performance.

For example, it can be used when,

Seq. writes (Data) + wait + Seq. writes (Node)

is pretty much slower than,

Rand. writes (Data)

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

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ad7e9b369319..8efa170352ff 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -386,6 +386,7 @@ struct f2fs_sm_info {
 
         unsigned int ipu_policy;        /* in-place-update policy */
         unsigned int min_ipu_util;      /* in-place-update threshold */
+        unsigned int min_fsync_blocks;  /* threshold for fsync */
 
         /* for flush command control */
         struct flush_cmd_control *cmd_control_info;