[PATCH RFC 3/5] f2fs: inherit mtime of original block during GC

[Chao Yu <yuchao0@huawei.com>]

Don't let f2fs inner GC ruins original aging degree of segment.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/data.c    |  2 +-
 fs/f2fs/f2fs.h    |  5 +++--
 fs/f2fs/gc.c      |  4 ++--
 fs/f2fs/segment.c | 55 ++++++++++++++++++++++++++++++++++++-----------
 4 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index d742f38b1445..062d585fa080 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1366,7 +1366,7 @@ static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
 	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
 	old_blkaddr = dn->data_blkaddr;
 	f2fs_allocate_data_block(sbi, NULL, old_blkaddr, &dn->data_blkaddr,
-					&sum, seg_type, NULL);
+				&sum, seg_type, NULL, false);
 	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
 		invalidate_mapping_pages(META_MAPPING(sbi),
 					old_blkaddr, old_blkaddr);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f06c77066284..a90702a725b6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3383,7 +3383,8 @@ void f2fs_outplace_write_data(struct dnode_of_data *dn,
 int f2fs_inplace_write_data(struct f2fs_io_info *fio);
 void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 			block_t old_blkaddr, block_t new_blkaddr,
-			bool recover_curseg, bool recover_newaddr);
+			bool recover_curseg, bool recover_newaddr,
+			bool from_gc);
 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,
@@ -3391,7 +3392,7 @@ void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
 void 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,
-			struct f2fs_io_info *fio);
+			struct f2fs_io_info *fio, bool from_gc);
 void f2fs_wait_on_page_writeback(struct page *page,
 			enum page_type type, bool ordered, bool locked);
 void f2fs_wait_on_block_writeback(struct inode *inode, block_t blkaddr);
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 84807abe4e00..e720886ef9bf 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -875,7 +875,7 @@ static int move_data_block(struct inode *inode, block_t bidx,
 	}
 
 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
-					&sum, CURSEG_COLD_DATA, NULL);
+				&sum, CURSEG_COLD_DATA, NULL, true);
 
 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
@@ -925,7 +925,7 @@ static int move_data_block(struct inode *inode, block_t bidx,
 recover_block:
 	if (err)
 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
-								true, true);
+							true, true, true);
 up_out:
 	if (lfs_mode)
 		up_write(&fio.sbi->io_order_lock);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 906c313835ad..0fde06b904c5 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2149,12 +2149,28 @@ static void __set_sit_entry_type(struct f2fs_sb_info *sbi, int type,
 	if (modified)
 		__mark_sit_entry_dirty(sbi, segno);
 }
+static inline unsigned long long get_segment_mtime(struct f2fs_sb_info *sbi,
+								block_t blkaddr)
+{
+	unsigned int segno = GET_SEGNO(sbi, blkaddr);
+
+	if (segno == NULL_SEGNO)
+		return 0;
+	return get_seg_entry(sbi, segno)->mtime;
+}
 
-static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr)
+static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr,
+						unsigned long long old_mtime)
 {
+	struct seg_entry *se;
 	unsigned int segno = GET_SEGNO(sbi, blkaddr);
-	struct seg_entry *se = get_seg_entry(sbi, segno);
-	unsigned long long mtime = get_mtime(sbi, false);
+	unsigned long long ctime = get_mtime(sbi, false);
+	unsigned long long mtime = old_mtime ? old_mtime : ctime;
+
+	if (segno == NULL_SEGNO)
+		return;
+
+	se = get_seg_entry(sbi, segno);
 
 	if (!se->mtime) {
 		se->mtime = mtime;
@@ -2162,8 +2178,8 @@ static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr)
 		se->mtime = (se->mtime * se->valid_blocks + mtime) /
 						(se->valid_blocks + 1);
 	}
-	if (mtime > SIT_I(sbi)->max_mtime)
-		SIT_I(sbi)->max_mtime = mtime;
+	if (ctime > SIT_I(sbi)->max_mtime)
+		SIT_I(sbi)->max_mtime = ctime;
 }
 
 static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
@@ -2185,8 +2201,6 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
 	f2fs_bug_on(sbi, (new_vblocks >> (sizeof(unsigned short) << 3) ||
 				(new_vblocks > sbi->blocks_per_seg)));
 
-	update_segment_mtime(sbi, blkaddr);
-
 	se->valid_blocks = new_vblocks;
 
 	/* Update valid block bitmap */
@@ -2280,6 +2294,7 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr)
 	/* add it into sit main buffer */
 	down_write(&sit_i->sentry_lock);
 
+	update_segment_mtime(sbi, addr, 0);
 	update_sit_entry(sbi, addr, -1);
 
 	/* add it into dirty seglist */
@@ -3188,10 +3203,11 @@ static int __get_segment_type(struct f2fs_io_info *fio)
 void 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,
-		struct f2fs_io_info *fio)
+		struct f2fs_io_info *fio, bool from_gc)
 {
 	struct sit_info *sit_i = SIT_I(sbi);
 	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	unsigned long long old_mtime;
 
 	down_read(&SM_I(sbi)->curseg_lock);
 
@@ -3213,6 +3229,14 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
 
 	stat_inc_block_count(sbi, curseg);
 
+	if (from_gc) {
+		old_mtime = get_segment_mtime(sbi, old_blkaddr);
+	} else {
+		update_segment_mtime(sbi, old_blkaddr, 0);
+		old_mtime = 0;
+	}
+	update_segment_mtime(sbi, *new_blkaddr, old_mtime);
+
 	/*
 	 * SIT information should be updated before segment allocation,
 	 * since SSR needs latest valid block information.
@@ -3289,7 +3313,8 @@ static void do_write_page(struct f2fs_summary *sum, struct f2fs_io_info *fio)
 		down_read(&fio->sbi->io_order_lock);
 reallocate:
 	f2fs_allocate_data_block(fio->sbi, fio->page, fio->old_blkaddr,
-			&fio->new_blkaddr, sum, type, fio);
+			&fio->new_blkaddr, sum, type, fio,
+			is_cold_data(fio->page));
 	if (GET_SEGNO(fio->sbi, fio->old_blkaddr) != NULL_SEGNO)
 		invalidate_mapping_pages(META_MAPPING(fio->sbi),
 					fio->old_blkaddr, fio->old_blkaddr);
@@ -3405,7 +3430,8 @@ static inline int __f2fs_get_curseg(struct f2fs_sb_info *sbi,
 
 void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 				block_t old_blkaddr, block_t new_blkaddr,
-				bool recover_curseg, bool recover_newaddr)
+				bool recover_curseg, bool recover_newaddr,
+				bool from_gc)
 {
 	struct sit_info *sit_i = SIT_I(sbi);
 	struct curseg_info *curseg;
@@ -3456,11 +3482,16 @@ void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
 	__add_sum_entry(sbi, type, sum);
 
-	if (!recover_curseg || recover_newaddr)
+	if (!recover_curseg || recover_newaddr) {
+		if (!from_gc)
+			update_segment_mtime(sbi, new_blkaddr, 0);
 		update_sit_entry(sbi, new_blkaddr, 1);
+	}
 	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO) {
 		invalidate_mapping_pages(META_MAPPING(sbi),
 					old_blkaddr, old_blkaddr);
+		if (!from_gc)
+			update_segment_mtime(sbi, old_blkaddr, 0);
 		update_sit_entry(sbi, old_blkaddr, -1);
 	}
 
@@ -3492,7 +3523,7 @@ void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
 	set_summary(&sum, dn->nid, dn->ofs_in_node, version);
 
 	f2fs_do_replace_block(sbi, &sum, old_addr, new_addr,
-					recover_curseg, recover_newaddr);
+					recover_curseg, recover_newaddr, false);
 
 	f2fs_update_data_blkaddr(dn, new_addr);
 }
-- 
2.26.2