f2fs: support passing down write hints given by users to block layer

Add the 'whint_mode' mount option that controls which write
hints are passed down to block layer. There are "off" and
"user-based" mode. The default mode is "off".

1) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.

2) whint_mode=user-based. F2FS tries to pass down hints given
by users.

User                  F2FS                     Block
----                  ----                     -----
                      META                     WRITE_LIFE_NOT_SET
                      HOT_NODE                 "
                      WARM_NODE                "
                      COLD_NODE                "
ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
extension list        "                        "

-- buffered 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_MEDIUM     "                        "
WRITE_LIFE_LONG       "                        "

-- 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

Many thanks to Chao Yu and Jaegeuk Kim for comments to
implement this patch.

Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: avoid build warning]
[Chao Yu: fix to restore whint_mode in ->remount_fs]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 21 insertions, 5 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 7578ed1a85e0..0dae8561addb 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -175,15 +175,22 @@ static bool __same_bdev(struct f2fs_sb_info *sbi,
  */
 static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
 				struct writeback_control *wbc,
-				int npages, bool is_read)
+				int npages, bool is_read,
+				enum page_type type, enum temp_type temp)
 {
 	struct bio *bio;
 
 	bio = f2fs_bio_alloc(sbi, npages, true);
 
 	f2fs_target_device(sbi, blk_addr, bio);
-	bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
-	bio->bi_private = is_read ? NULL : sbi;
+	if (is_read) {
+		bio->bi_end_io = f2fs_read_end_io;
+		bio->bi_private = NULL;
+	} else {
+		bio->bi_end_io = f2fs_write_end_io;
+		bio->bi_private = sbi;
+		bio->bi_write_hint = io_type_to_rw_hint(sbi, type, temp);
+	}
 	if (wbc)
 		wbc_init_bio(wbc, bio);
 
@@ -382,7 +389,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 
 	/* Allocate a new bio */
 	bio = __bio_alloc(fio->sbi, fio->new_blkaddr, fio->io_wbc,
-				1, is_read_io(fio->op));
+				1, is_read_io(fio->op), fio->type, fio->temp);
 
 	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
 		bio_put(bio);
@@ -445,7 +452,8 @@ alloc_new:
 			goto out_fail;
 		}
 		io->bio = __bio_alloc(sbi, fio->new_blkaddr, fio->io_wbc,
-						BIO_MAX_PAGES, false);
+						BIO_MAX_PAGES, false,
+						fio->type, fio->temp);
 		io->fio = *fio;
 	}
 
@@ -2287,10 +2295,13 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct address_space *mapping = iocb->ki_filp->f_mapping;
 	struct inode *inode = mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	size_t count = iov_iter_count(iter);
 	loff_t offset = iocb->ki_pos;
 	int rw = iov_iter_rw(iter);
 	int err;
+	enum rw_hint hint = iocb->ki_hint;
+	int whint_mode = sbi->whint_mode;
 
 	err = check_direct_IO(inode, iter, offset);
 	if (err)
@@ -2301,11 +2312,16 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 
 	trace_f2fs_direct_IO_enter(inode, offset, count, rw);
 
+	if (rw == WRITE && whint_mode == WHINT_MODE_OFF)
+		iocb->ki_hint = WRITE_LIFE_NOT_SET;
+
 	down_read(&F2FS_I(inode)->dio_rwsem[rw]);
 	err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
 	up_read(&F2FS_I(inode)->dio_rwsem[rw]);
 
 	if (rw == WRITE) {
+		if (whint_mode == WHINT_MODE_OFF)
+			iocb->ki_hint = hint;
 		if (err > 0) {
 			f2fs_update_iostat(F2FS_I_SB(inode), APP_DIRECT_IO,
 									err);