f2fs: compress: fix to avoid fragment w/ OPU during f2fs_ioc_compress_file()

If file has both cold and compress flag, during f2fs_ioc_compress_file(),
f2fs will trigger IPU for non-compress cluster and OPU for compress
cluster, so that, data of the file may be fragmented.

Fix it by always triggering OPU for IOs from user mode compression.
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -2665,6 +2665,11 @@ bool f2fs_should_update_outplace(struct inode *inode, struct f2fs_io_info *fio)
 		return true;
 	if (f2fs_is_atomic_file(inode))
 		return true;
+	/* rewrite low ratio compress data w/ OPU mode to avoid fragmentation */
+	if (f2fs_compressed_file(inode) &&
+		F2FS_OPTION(sbi).compress_mode == COMPR_MODE_USER &&
+		is_inode_flag_set(inode, FI_ENABLE_COMPRESS))
+		return true;
 
 	/* swap file is migrating in aligned write mode */
 	if (is_inode_flag_set(inode, FI_ALIGNED_WRITE))