f2fs: support multiple devices

This patch implements multiple devices support for f2fs.
Given multiple devices by mkfs.f2fs, f2fs shows them entirely as one big
volume under one f2fs instance.

Internal block management is very simple, but we will modify block allocation
and background GC policy to boost IO speed by exploiting them accoording to
each device speed.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 86 insertions, 33 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 4cc589a493e3..1869bc3973d5 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -403,6 +403,33 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
 	}
 }
 
+static int __submit_flush_wait(struct block_device *bdev)
+{
+	struct bio *bio = f2fs_bio_alloc(0);
+	int ret;
+
+	bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_FLUSH);
+	bio->bi_bdev = bdev;
+	ret = submit_bio_wait(bio);
+	bio_put(bio);
+	return ret;
+}
+
+static int submit_flush_wait(struct f2fs_sb_info *sbi)
+{
+	int ret = __submit_flush_wait(sbi->sb->s_bdev);
+	int i;
+
+	if (sbi->s_ndevs && !ret) {
+		for (i = 1; i < sbi->s_ndevs; i++) {
+			ret = __submit_flush_wait(FDEV(i).bdev);
+			if (ret)
+				break;
+		}
+	}
+	return ret;
+}
+
 static int issue_flush_thread(void *data)
 {
 	struct f2fs_sb_info *sbi = data;
@@ -413,25 +440,18 @@ repeat:
 		return 0;
 
 	if (!llist_empty(&fcc->issue_list)) {
-		struct bio *bio;
 		struct flush_cmd *cmd, *next;
 		int ret;
 
-		bio = f2fs_bio_alloc(0);
-
 		fcc->dispatch_list = llist_del_all(&fcc->issue_list);
 		fcc->dispatch_list = llist_reverse_order(fcc->dispatch_list);
 
-		bio->bi_bdev = sbi->sb->s_bdev;
-		bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_FLUSH);
-		ret = submit_bio_wait(bio);
-
+		ret = submit_flush_wait(sbi);
 		llist_for_each_entry_safe(cmd, next,
 					  fcc->dispatch_list, llnode) {
 			cmd->ret = ret;
 			complete(&cmd->wait);
 		}
-		bio_put(bio);
 		fcc->dispatch_list = NULL;
 	}
 
@@ -452,15 +472,11 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi)
 		return 0;
 
 	if (!test_opt(sbi, FLUSH_MERGE) || !atomic_read(&fcc->submit_flush)) {
-		struct bio *bio = f2fs_bio_alloc(0);
 		int ret;
 
 		atomic_inc(&fcc->submit_flush);
-		bio->bi_bdev = sbi->sb->s_bdev;
-		bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_FLUSH);
-		ret = submit_bio_wait(bio);
+		ret = submit_flush_wait(sbi);
 		atomic_dec(&fcc->submit_flush);
-		bio_put(bio);
 		return ret;
 	}
 
@@ -637,14 +653,18 @@ static void f2fs_submit_bio_wait_endio(struct bio *bio)
 
 /* this function is copied from blkdev_issue_discard from block/blk-lib.c */
 static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi,
-				block_t blkstart, block_t blklen)
+		struct block_device *bdev, block_t blkstart, block_t blklen)
 {
-	struct block_device *bdev = sbi->sb->s_bdev;
 	struct bio *bio = NULL;
 	int err;
 
 	trace_f2fs_issue_discard(sbi->sb, blkstart, blklen);
 
+	if (sbi->s_ndevs) {
+		int devi = f2fs_target_device_index(sbi, blkstart);
+
+		blkstart -= FDEV(devi).start_blk;
+	}
 	err = __blkdev_issue_discard(bdev,
 				SECTOR_FROM_BLOCK(blkstart),
 				SECTOR_FROM_BLOCK(blklen),
@@ -662,18 +682,24 @@ static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi,
 }
 
 #ifdef CONFIG_BLK_DEV_ZONED
-static int f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
-					block_t blkstart, block_t blklen)
+static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
 {
-	sector_t sector = SECTOR_FROM_BLOCK(blkstart);
 	sector_t nr_sects = SECTOR_FROM_BLOCK(blklen);
-	struct block_device *bdev = sbi->sb->s_bdev;
+	sector_t sector;
+	int devi = 0;
 
-	if (nr_sects != bdev_zone_size(bdev)) {
+	if (sbi->s_ndevs) {
+		devi = f2fs_target_device_index(sbi, blkstart);
+		blkstart -= FDEV(devi).start_blk;
+	}
+	sector = SECTOR_FROM_BLOCK(blkstart);
+
+	if (sector % bdev_zone_size(bdev) || nr_sects != bdev_zone_size(bdev)) {
 		f2fs_msg(sbi->sb, KERN_INFO,
-			 "Unaligned discard attempted (sector %llu + %llu)",
-			 (unsigned long long)sector,
-			 (unsigned long long)nr_sects);
+			"(%d) %s: Unaligned discard attempted (block %x + %x)",
+			devi, sbi->s_ndevs ? FDEV(devi).path: "",
+			blkstart, blklen);
 		return -EIO;
 	}
 
@@ -682,14 +708,12 @@ static int f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
 	 * use regular discard if the drive supports it. For sequential
 	 * zones, reset the zone write pointer.
 	 */
-	switch (get_blkz_type(sbi, blkstart)) {
+	switch (get_blkz_type(sbi, bdev, blkstart)) {
 
 	case BLK_ZONE_TYPE_CONVENTIONAL:
 		if (!blk_queue_discard(bdev_get_queue(bdev)))
 			return 0;
-		return __f2fs_issue_discard_async(sbi, blkstart,
-						  blklen);
-
+		return __f2fs_issue_discard_async(sbi, bdev, blkstart, blklen);
 	case BLK_ZONE_TYPE_SEQWRITE_REQ:
 	case BLK_ZONE_TYPE_SEQWRITE_PREF:
 		trace_f2fs_issue_reset_zone(sbi->sb, blkstart);
@@ -702,14 +726,45 @@ static int f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
 }
 #endif
 
+static int __issue_discard_async(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+#ifdef CONFIG_BLK_DEV_ZONED
+	if (f2fs_sb_mounted_blkzoned(sbi->sb) &&
+				bdev_zoned_model(bdev) != BLK_ZONED_NONE)
+		return __f2fs_issue_discard_zone(sbi, bdev, blkstart, blklen);
+#endif
+	return __f2fs_issue_discard_async(sbi, bdev, blkstart, blklen);
+}
+
 static int f2fs_issue_discard(struct f2fs_sb_info *sbi,
 				block_t blkstart, block_t blklen)
 {
+	sector_t start = blkstart, len = 0;
+	struct block_device *bdev;
 	struct seg_entry *se;
 	unsigned int offset;
 	block_t i;
+	int err = 0;
+
+	bdev = f2fs_target_device(sbi, blkstart, NULL);
+
+	for (i = blkstart; i < blkstart + blklen; i++, len++) {
+		if (i != start) {
+			struct block_device *bdev2 =
+				f2fs_target_device(sbi, i, NULL);
+
+			if (bdev2 != bdev) {
+				err = __issue_discard_async(sbi, bdev,
+						start, len);
+				if (err)
+					return err;
+				bdev = bdev2;
+				start = i;
+				len = 0;
+			}
+		}
 
-	for (i = blkstart; i < blkstart + blklen; i++) {
 		se = get_seg_entry(sbi, GET_SEGNO(sbi, i));
 		offset = GET_BLKOFF_FROM_SEG0(sbi, i);
 
@@ -717,11 +772,9 @@ static int f2fs_issue_discard(struct f2fs_sb_info *sbi,
 			sbi->discard_blks--;
 	}
 
-#ifdef CONFIG_BLK_DEV_ZONED
-	if (f2fs_sb_mounted_blkzoned(sbi->sb))
-		return f2fs_issue_discard_zone(sbi, blkstart, blklen);
-#endif
-	return __f2fs_issue_discard_async(sbi, blkstart, blklen);
+	if (len)
+		err = __issue_discard_async(sbi, bdev, start, len);
+	return err;
 }
 
 static void __add_discard_entry(struct f2fs_sb_info *sbi,