f2fs: support file defragment
This patch introduces a new ioctl F2FS_IOC_DEFRAGMENT to support file
defragment in a specified range of regular file.
This ioctl can be used in very limited workload: if user expects high
sequential read performance in randomly written file, this interface
can be used for defragmentation, after that file can be written as
continuous as possible in the device.
Meanwhile, it has side-effect, it will make holes in segments where
blocks located originally, so it's better to trigger GC to eliminate
fragment in segments.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 0cc8de2..c3e1ffa 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -566,7 +566,7 @@
* b. do not use extent cache for better performance
* c. give the block addresses to blockdev
*/
-static int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
+int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
int create, int flag)
{
unsigned int maxblocks = map->m_len;
@@ -1355,6 +1355,10 @@
available_free_memory(sbi, DIRTY_DENTS))
goto skip_write;
+ /* skip writing during file defragment */
+ if (is_inode_flag_set(F2FS_I(inode), FI_DO_DEFRAG))
+ goto skip_write;
+
/* during POR, we don't need to trigger writepage at all. */
if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
goto skip_write;