[PATCH 2/2] f2fs: manage zone capacity during writes and gc

[Aravind Ramesh <aravind.ramesh@wdc.com>]

Manage the usable segments in a section and usable blocks per segment
during write and gc. Segments which are beyond zone-capacity are never
allocated, and do not need to be garbage collected, only the segments
which are before zone-capacity needs to garbage collected.
For spanning segments based on the number of usable blocks in that
segment, write to blocks only up to zone-capacity.

Signed-off-by: Aravind Ramesh <aravind.ramesh@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 fs/f2fs/gc.c      | 27 ++++++++++++++++++++-------
 fs/f2fs/gc.h      | 42 ++++++++++++++++++++++++++++++++++++++----
 fs/f2fs/segment.c | 18 ++++++++++--------
 fs/f2fs/segment.h |  6 +++---
 4 files changed, 71 insertions(+), 22 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 9a40761445d3..dfa6d91cffcb 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -266,13 +266,14 @@ static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 	unsigned char age = 0;
 	unsigned char u;
 	unsigned int i;
+	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
 
-	for (i = 0; i < sbi->segs_per_sec; i++)
+	for (i = 0; i < usable_segs_per_sec; i++)
 		mtime += get_seg_entry(sbi, start + i)->mtime;
 	vblocks = get_valid_blocks(sbi, segno, true);
 
-	mtime = div_u64(mtime, sbi->segs_per_sec);
-	vblocks = div_u64(vblocks, sbi->segs_per_sec);
+	mtime = div_u64(mtime, usable_segs_per_sec);
+	vblocks = div_u64(vblocks, usable_segs_per_sec);
 
 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 
@@ -536,6 +537,7 @@ static int gc_node_segment(struct f2fs_sb_info *sbi,
 	int phase = 0;
 	bool fggc = (gc_type == FG_GC);
 	int submitted = 0;
+	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
 
 	start_addr = START_BLOCK(sbi, segno);
 
@@ -545,7 +547,7 @@ static int gc_node_segment(struct f2fs_sb_info *sbi,
 	if (fggc && phase == 2)
 		atomic_inc(&sbi->wb_sync_req[NODE]);
 
-	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
+	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
 		nid_t nid = le32_to_cpu(entry->nid);
 		struct page *node_page;
 		struct node_info ni;
@@ -1033,13 +1035,14 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 	int off;
 	int phase = 0;
 	int submitted = 0;
+	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
 
 	start_addr = START_BLOCK(sbi, segno);
 
 next_step:
 	entry = sum;
 
-	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
+	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
 		struct page *data_page;
 		struct inode *inode;
 		struct node_info dni; /* dnode info for the data */
@@ -1201,7 +1204,16 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 						SUM_TYPE_DATA : SUM_TYPE_NODE;
 	int submitted = 0;
 
-	if (__is_large_section(sbi))
+       /*
+	* zone-capacity can be less than zone-size in zoned devices,
+	* resulting in less than expected usable segments in the zone,
+	* calculate the end segno in the zone which can be garbage collected
+	*/
+	if (f2fs_sb_has_blkzoned(sbi))
+		end_segno -= sbi->segs_per_sec -
+					f2fs_usable_segs_in_sec(sbi, segno);
+
+	else if (__is_large_section(sbi))
 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
 
 	/* readahead multi ssa blocks those have contiguous address */
@@ -1356,7 +1368,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 		goto stop;
 
 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
-	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
+	if (gc_type == FG_GC &&
+		seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
 		sec_freed++;
 	total_freed += seg_freed;
 
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index db3c61046aa4..463b4e38b864 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -44,13 +44,47 @@ struct gc_inode_list {
 /*
  * inline functions
  */
+
+/*
+ * On a Zoned device zone-capacity can be less than zone-size and if
+ * zone-capacity is not aligned to f2fs segment size(2MB), then the segment
+ * starting just before zone-capacity has some blocks spanning across the
+ * zone-capacity, these blocks are not usable.
+ * Such spanning segments can be in free list so calculate the sum of usable
+ * blocks in currently free segments including normal and spanning segments.
+ */
+static inline block_t free_segs_blk_count_zoned(struct f2fs_sb_info *sbi)
+{
+	block_t free_seg_blks = 0;
+	struct free_segmap_info *free_i = FREE_I(sbi);
+	int j;
+
+	for (j = 0; j < MAIN_SEGS(sbi); j++)
+		if (!test_bit(j, free_i->free_segmap))
+			free_seg_blks += f2fs_usable_blks_in_seg(sbi, j);
+
+	return free_seg_blks;
+}
+
+static inline block_t free_segs_blk_count(struct f2fs_sb_info *sbi)
+{
+	if (f2fs_sb_has_blkzoned(sbi))
+		return free_segs_blk_count_zoned(sbi);
+
+	return free_segments(sbi) << sbi->log_blocks_per_seg;
+}
+
 static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
 {
-	if (free_segments(sbi) < overprovision_segments(sbi))
+	block_t free_blks, ovp_blks;
+
+	free_blks = free_segs_blk_count(sbi);
+	ovp_blks = overprovision_segments(sbi) << sbi->log_blocks_per_seg;
+
+	if (free_blks < ovp_blks)
 		return 0;
-	else
-		return (free_segments(sbi) - overprovision_segments(sbi))
-			<< sbi->log_blocks_per_seg;
+
+	return free_blks - ovp_blks;
 }
 
 static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d2156f3f56a5..d75c1849dc83 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -869,10 +869,10 @@ static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno)
 	ckpt_valid_blocks = get_ckpt_valid_blocks(sbi, segno);
 
 	if (valid_blocks == 0 && (!is_sbi_flag_set(sbi, SBI_CP_DISABLED) ||
-				ckpt_valid_blocks == sbi->blocks_per_seg)) {
+		ckpt_valid_blocks == f2fs_usable_blks_in_seg(sbi, segno))) {
 		__locate_dirty_segment(sbi, segno, PRE);
 		__remove_dirty_segment(sbi, segno, DIRTY);
-	} else if (valid_blocks < sbi->blocks_per_seg) {
+	} else if (valid_blocks < f2fs_usable_blks_in_seg(sbi, segno)) {
 		__locate_dirty_segment(sbi, segno, DIRTY);
 	} else {
 		/* Recovery routine with SSR needs this */
@@ -915,9 +915,11 @@ block_t f2fs_get_unusable_blocks(struct f2fs_sb_info *sbi)
 	for_each_set_bit(segno, dirty_i->dirty_segmap[DIRTY], MAIN_SEGS(sbi)) {
 		se = get_seg_entry(sbi, segno);
 		if (IS_NODESEG(se->type))
-			holes[NODE] += sbi->blocks_per_seg - se->valid_blocks;
+			holes[NODE] += f2fs_usable_blks_in_seg(sbi, segno) -
+							se->valid_blocks;
 		else
-			holes[DATA] += sbi->blocks_per_seg - se->valid_blocks;
+			holes[DATA] += f2fs_usable_blks_in_seg(sbi, segno) -
+							se->valid_blocks;
 	}
 	mutex_unlock(&dirty_i->seglist_lock);
 
@@ -2167,7 +2169,7 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
 	offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
 
 	f2fs_bug_on(sbi, (new_vblocks >> (sizeof(unsigned short) << 3) ||
-				(new_vblocks > sbi->blocks_per_seg)));
+			(new_vblocks > f2fs_usable_blks_in_seg(sbi, segno))));
 
 	se->valid_blocks = new_vblocks;
 	se->mtime = get_mtime(sbi, false);
@@ -2933,9 +2935,9 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 static bool __has_curseg_space(struct f2fs_sb_info *sbi, int type)
 {
 	struct curseg_info *curseg = CURSEG_I(sbi, type);
-	if (curseg->next_blkoff < sbi->blocks_per_seg)
-		return true;
-	return false;
+
+	return curseg->next_blkoff < f2fs_usable_blks_in_seg(sbi,
+							curseg->segno);
 }
 
 int f2fs_rw_hint_to_seg_type(enum rw_hint hint)
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 79b0dc33feaf..170df8c84f75 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -548,8 +548,8 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi)
 	/* check current node segment */
 	for (i = CURSEG_HOT_NODE; i <= CURSEG_COLD_NODE; i++) {
 		segno = CURSEG_I(sbi, i)->segno;
-		left_blocks = sbi->blocks_per_seg -
-			get_seg_entry(sbi, segno)->ckpt_valid_blocks;
+		left_blocks = f2fs_usable_blks_in_seg(sbi, segno) -
+				get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 
 		if (node_blocks > left_blocks)
 			return false;
@@ -557,7 +557,7 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi)
 
 	/* check current data segment */
 	segno = CURSEG_I(sbi, CURSEG_HOT_DATA)->segno;
-	left_blocks = sbi->blocks_per_seg -
+	left_blocks = f2fs_usable_blks_in_seg(sbi, segno) -
 			get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 	if (dent_blocks > left_blocks)
 		return false;
-- 
2.19.1