f2fs: merge equivalent flags F2FS_GET_BLOCK_[READ|DIO]

Currently, the two flags F2FS_GET_BLOCK_[READ|DIO] are totally equivalent
and can be used interchangably in all scenarios they are involved in.
Neither of the flags is referenced in f2fs_map_blocks(), making them both
the default case. To remove the ambiguity, this patch merges both flags
into F2FS_GET_BLOCK_DEFAULT, and introduces an enum for all distinct flags.

Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1044,7 +1044,7 @@ static int get_data_block_dio(struct inode *inode, sector_t iblock,
 			struct buffer_head *bh_result, int create)
 {
 	return __get_data_block(inode, iblock, bh_result, create,
-						F2FS_GET_BLOCK_DIO, NULL);
+						F2FS_GET_BLOCK_DEFAULT, NULL);
 }
 
 static int get_data_block_bmap(struct inode *inode, sector_t iblock,
@@ -1244,7 +1244,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 			map.m_len = last_block - block_in_file;
 
 			if (f2fs_map_blocks(inode, &map, 0,
-						F2FS_GET_BLOCK_READ))
+						F2FS_GET_BLOCK_DEFAULT))
 				goto set_error_page;
 		}
 got_it:

fs/f2fs/f2fs.h

@@ -510,12 +510,13 @@ struct f2fs_map_blocks {
 };
 
 /* for flag in get_data_block */
-#define F2FS_GET_BLOCK_READ		0
-#define F2FS_GET_BLOCK_DIO		1
-#define F2FS_GET_BLOCK_FIEMAP		2
-#define F2FS_GET_BLOCK_BMAP		3
-#define F2FS_GET_BLOCK_PRE_DIO		4
-#define F2FS_GET_BLOCK_PRE_AIO		5
+enum {
+	F2FS_GET_BLOCK_DEFAULT,
+	F2FS_GET_BLOCK_FIEMAP,
+	F2FS_GET_BLOCK_BMAP,
+	F2FS_GET_BLOCK_PRE_DIO,
+	F2FS_GET_BLOCK_PRE_AIO,
+};
 
 /*
  * i_advise uses FADVISE_XXX_BIT. We can add additional hints later.

fs/f2fs/file.c

@@ -2074,7 +2074,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	 */
 	while (map.m_lblk < pg_end) {
 		map.m_len = pg_end - map.m_lblk;
-		err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_READ);
+		err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_DEFAULT);
 		if (err)
 			goto out;
 
@@ -2116,7 +2116,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 
 do_map:
 		map.m_len = pg_end - map.m_lblk;
-		err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_READ);
+		err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_DEFAULT);
 		if (err)
 			goto clear_out;