f2fs: assign the write hint per stream by default

This reverts commit 930e2607 ("f2fs: remove obsolete whint_mode"), as we
decide to pass write hints to the disk.

Cc: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Documentation/filesystems/f2fs.rst

@@ -774,6 +774,35 @@ In order to identify whether the data in the victim segment are valid or not,
 F2FS manages a bitmap. Each bit represents the validity of a block, and the
 bitmap is composed of a bit stream covering whole blocks in main area.
 
+Write-hint Policy
+-----------------
+
+F2FS sets the whint all the time with the below policy.
+
+===================== ======================== ===================
+User                  F2FS                     Block
+===================== ======================== ===================
+N/A                   META                     WRITE_LIFE_NONE|REQ_META
+N/A                   HOT_NODE                 WRITE_LIFE_NONE
+N/A                   WARM_NODE                WRITE_LIFE_MEDIUM
+N/A                   COLD_NODE                WRITE_LIFE_LONG
+ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
+extension list        "                        "
+
+-- buffered io
+N/A                   COLD_DATA                WRITE_LIFE_EXTREME
+N/A                   HOT_DATA                 WRITE_LIFE_SHORT
+N/A                   WARM_DATA                WRITE_LIFE_NOT_SET
+
+-- direct io
+WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
+WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
+WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
+WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE
+WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM
+WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG
+===================== ======================== ===================
+
 Fallocate(2) Policy
 -------------------
 

fs/f2fs/data.c

@@ -465,6 +465,8 @@ static struct bio *__bio_alloc(struct f2fs_io_info *fio, int npages)
 	} else {
 		bio->bi_end_io = f2fs_write_end_io;
 		bio->bi_private = sbi;
+		bio->bi_write_hint = f2fs_io_type_to_rw_hint(sbi,
+						fio->type, fio->temp);
 	}
 	iostat_alloc_and_bind_ctx(sbi, bio, NULL);
 

fs/f2fs/f2fs.h

@@ -3722,6 +3722,7 @@ void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
 			block_t old_addr, block_t new_addr,
 			unsigned char version, bool recover_curseg,
 			bool recover_newaddr);
+int f2fs_get_segment_temp(int seg_type);
 int f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
 			block_t old_blkaddr, block_t *new_blkaddr,
 			struct f2fs_summary *sum, int type,
@@ -3745,6 +3746,8 @@ void f2fs_destroy_segment_manager(struct f2fs_sb_info *sbi);
 int __init f2fs_create_segment_manager_caches(void);
 void f2fs_destroy_segment_manager_caches(void);
 int f2fs_rw_hint_to_seg_type(enum rw_hint hint);
+enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
+			enum page_type type, enum temp_type temp);
 unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi,
 			unsigned int segno);
 unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,

fs/f2fs/file.c

@@ -4685,8 +4685,21 @@ static int f2fs_dio_write_end_io(struct kiocb *iocb, ssize_t size, int error,
 	return 0;
 }
 
+static void f2fs_dio_write_submit_io(const struct iomap_iter *iter,
+					struct bio *bio, loff_t file_offset)
+{
+	struct inode *inode = iter->inode;
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	int seg_type = f2fs_rw_hint_to_seg_type(inode->i_write_hint);
+	enum temp_type temp = f2fs_get_segment_temp(seg_type);
+
+	bio->bi_write_hint = f2fs_io_type_to_rw_hint(sbi, DATA, temp);
+	submit_bio(bio);
+}
+
 static const struct iomap_dio_ops f2fs_iomap_dio_write_ops = {
-	.end_io = f2fs_dio_write_end_io,
+	.end_io		= f2fs_dio_write_end_io,
+	.submit_io	= f2fs_dio_write_submit_io,
 };
 
 static void f2fs_flush_buffered_write(struct address_space *mapping,

fs/f2fs/segment.c

@@ -3364,6 +3364,65 @@ int f2fs_rw_hint_to_seg_type(enum rw_hint hint)
 	}
 }
 
+/*
+ * This returns write hints for each segment type. This hints will be
+ * passed down to block layer as below by default.
+ *
+ * User                  F2FS                     Block
+ * ----                  ----                     -----
+ *                       META                     WRITE_LIFE_NONE|REQ_META
+ *                       HOT_NODE                 WRITE_LIFE_NONE
+ *                       WARM_NODE                WRITE_LIFE_MEDIUM
+ *                       COLD_NODE                WRITE_LIFE_LONG
+ * ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
+ * extension list        "                        "
+ *
+ * -- buffered io
+ *                       COLD_DATA                WRITE_LIFE_EXTREME
+ *                       HOT_DATA                 WRITE_LIFE_SHORT
+ *                       WARM_DATA                WRITE_LIFE_NOT_SET
+ *
+ * -- direct io
+ * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
+ * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
+ * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
+ * WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE
+ * WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM
+ * WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG
+ */
+enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
+				enum page_type type, enum temp_type temp)
+{
+	switch (type) {
+	case DATA:
+		switch (temp) {
+		case WARM:
+			return WRITE_LIFE_NOT_SET;
+		case HOT:
+			return WRITE_LIFE_SHORT;
+		case COLD:
+			return WRITE_LIFE_EXTREME;
+		default:
+			return WRITE_LIFE_NONE;
+		}
+	case NODE:
+		switch (temp) {
+		case WARM:
+			return WRITE_LIFE_MEDIUM;
+		case HOT:
+			return WRITE_LIFE_NONE;
+		case COLD:
+			return WRITE_LIFE_LONG;
+		default:
+			return WRITE_LIFE_NONE;
+		}
+	case META:
+		return WRITE_LIFE_NONE;
+	default:
+		return WRITE_LIFE_NONE;
+	}
+}
+
 static int __get_segment_type_2(struct f2fs_io_info *fio)
 {
 	if (fio->type == DATA)
@@ -3443,6 +3502,15 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
 	}
 }
 
+int f2fs_get_segment_temp(int seg_type)
+{
+	if (IS_HOT(seg_type))
+		return HOT;
+	else if (IS_WARM(seg_type))
+		return WARM;
+	return COLD;
+}
+
 static int __get_segment_type(struct f2fs_io_info *fio)
 {
 	int type = 0;
@@ -3461,12 +3529,8 @@ static int __get_segment_type(struct f2fs_io_info *fio)
 		f2fs_bug_on(fio->sbi, true);
 	}
 
-	if (IS_HOT(type))
-		fio->temp = HOT;
-	else if (IS_WARM(type))
-		fio->temp = WARM;
-	else
-		fio->temp = COLD;
+	fio->temp = f2fs_get_segment_temp(type);
+
 	return type;
 }