f2fs: invalidate meta pages only for post_read required inode

After commit e3b49ea3 ("f2fs: invalidate META_MAPPING before
IPU/DIO write"), invalidate_mapping_pages() will be called to
avoid race condition in between IPU/DIO and readahead for GC.

However, readahead flow is only used for post_read required inode,
so this patch adds check condition to avoids unnecessary page cache
invalidating for non-post_read inode.
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1463,12 +1463,9 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 			*map->m_next_extent = pgofs + map->m_len;
 
 		/* for hardware encryption, but to avoid potential issue in future */
-		if (flag == F2FS_GET_BLOCK_DIO) {
+		if (flag == F2FS_GET_BLOCK_DIO)
 			f2fs_wait_on_block_writeback_range(inode,
 						map->m_pblk, map->m_len);
-			invalidate_mapping_pages(META_MAPPING(sbi),
-				map->m_pblk, map->m_pblk + map->m_len - 1);
-		}
 
 		if (map->m_multidev_dio) {
 			block_t blk_addr = map->m_pblk;
@@ -1684,8 +1681,6 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 		 */
 		f2fs_wait_on_block_writeback_range(inode,
 						map->m_pblk, map->m_len);
-		invalidate_mapping_pages(META_MAPPING(sbi),
-				map->m_pblk, map->m_pblk + map->m_len - 1);
 
 		if (map->m_multidev_dio) {
 			block_t blk_addr = map->m_pblk;
@@ -2733,6 +2728,7 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
 		.submitted = false,
 		.compr_blocks = compr_blocks,
 		.need_lock = LOCK_RETRY,
+		.post_read = f2fs_post_read_required(inode),
 		.io_type = io_type,
 		.io_wbc = wbc,
 		.bio = bio,

fs/f2fs/f2fs.h

@@ -1199,6 +1199,7 @@ struct f2fs_io_info {
 	bool retry;		/* need to reallocate block address */
 	int compr_blocks;	/* # of compressed block addresses */
 	bool encrypted;		/* indicate file is encrypted */
+	bool post_read;		/* require post read */
 	enum iostat_type io_type;	/* io type */
 	struct writeback_control *io_wbc; /* writeback control */
 	struct bio **bio;		/* bio for ipu */

fs/f2fs/segment.c

@@ -3433,7 +3433,8 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
 		goto drop_bio;
 	}
 
-	invalidate_mapping_pages(META_MAPPING(sbi),
+	if (fio->post_read)
+		invalidate_mapping_pages(META_MAPPING(sbi),
 				fio->new_blkaddr, fio->new_blkaddr);
 
 	stat_inc_inplace_blocks(fio->sbi);
@@ -3616,10 +3617,16 @@ void f2fs_wait_on_block_writeback(struct inode *inode, block_t blkaddr)
 void f2fs_wait_on_block_writeback_range(struct inode *inode, block_t blkaddr,
 								block_t len)
 {
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	block_t i;
 
+	if (!f2fs_post_read_required(inode))
+		return;
+
 	for (i = 0; i < len; i++)
 		f2fs_wait_on_block_writeback(inode, blkaddr + i);
+
+	invalidate_mapping_pages(META_MAPPING(sbi), blkaddr, blkaddr + len - 1);
 }
 
 static int read_compacted_summaries(struct f2fs_sb_info *sbi)