[PATCH v4] f2fs: rebuild nat_bits during umount

[Chao Yu <chao@kernel.org>]

If all free_nat_bitmap are available, we can rebuild nat_bits from
free_nat_bitmap entirely during umount, let's make another chance
to reenable nat_bits for image.

Signed-off-by: Chao Yu <chao@kernel.org>
---
v4:
- rebase to last dev-branch
 fs/f2fs/checkpoint.c |  21 ++++++---
 fs/f2fs/f2fs.h       |  32 +-------------
 fs/f2fs/node.c       | 101 +++++++++++++++++++++++++++++++++----------
 3 files changed, 95 insertions(+), 59 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 41960c55c343..b75b52e2017e 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1302,12 +1302,20 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
 	unsigned long flags;
 
-	spin_lock_irqsave(&sbi->cp_lock, flags);
+	if (cpc->reason & CP_UMOUNT) {
+		if (le32_to_cpu(ckpt->cp_pack_total_block_count) >
+			sbi->blocks_per_seg - NM_I(sbi)->nat_bits_blocks) {
+			clear_ckpt_flags(sbi, CP_NAT_BITS_FLAG);
+			f2fs_notice(sbi, "Disable nat_bits due to no space");
+		} else if (!is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG) &&
+						f2fs_nat_bitmap_enabled(sbi)) {
+			f2fs_enable_nat_bits(sbi);
+			set_ckpt_flags(sbi, CP_NAT_BITS_FLAG);
+			f2fs_notice(sbi, "Rebuild and enable nat_bits");
+		}
+	}
 
-	if ((cpc->reason & CP_UMOUNT) &&
-			le32_to_cpu(ckpt->cp_pack_total_block_count) >
-			sbi->blocks_per_seg - NM_I(sbi)->nat_bits_blocks)
-		disable_nat_bits(sbi, false);
+	spin_lock_irqsave(&sbi->cp_lock, flags);
 
 	if (cpc->reason & CP_TRIMMED)
 		__set_ckpt_flags(ckpt, CP_TRIMMED_FLAG);
@@ -1493,7 +1501,8 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	start_blk = __start_cp_next_addr(sbi);
 
 	/* write nat bits */
-	if (enabled_nat_bits(sbi, cpc)) {
+	if ((cpc->reason & CP_UMOUNT) &&
+			is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG)) {
 		__u64 cp_ver = cur_cp_version(ckpt);
 		block_t blk;
 
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index fe1097e678da..340097544bfe 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2078,36 +2078,6 @@ static inline void clear_ckpt_flags(struct f2fs_sb_info *sbi, unsigned int f)
 	spin_unlock_irqrestore(&sbi->cp_lock, flags);
 }
 
-static inline void disable_nat_bits(struct f2fs_sb_info *sbi, bool lock)
-{
-	unsigned long flags;
-	unsigned char *nat_bits;
-
-	/*
-	 * In order to re-enable nat_bits we need to call fsck.f2fs by
-	 * set_sbi_flag(sbi, SBI_NEED_FSCK). But it may give huge cost,
-	 * so let's rely on regular fsck or unclean shutdown.
-	 */
-
-	if (lock)
-		spin_lock_irqsave(&sbi->cp_lock, flags);
-	__clear_ckpt_flags(F2FS_CKPT(sbi), CP_NAT_BITS_FLAG);
-	nat_bits = NM_I(sbi)->nat_bits;
-	NM_I(sbi)->nat_bits = NULL;
-	if (lock)
-		spin_unlock_irqrestore(&sbi->cp_lock, flags);
-
-	kvfree(nat_bits);
-}
-
-static inline bool enabled_nat_bits(struct f2fs_sb_info *sbi,
-					struct cp_control *cpc)
-{
-	bool set = is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG);
-
-	return (cpc) ? (cpc->reason & CP_UMOUNT) && set : set;
-}
-
 static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
 {
 	down_read(&sbi->cp_rwsem);
@@ -3543,6 +3513,7 @@ int f2fs_truncate_inode_blocks(struct inode *inode, pgoff_t from);
 int f2fs_truncate_xattr_node(struct inode *inode);
 int f2fs_wait_on_node_pages_writeback(struct f2fs_sb_info *sbi,
 					unsigned int seq_id);
+bool f2fs_nat_bitmap_enabled(struct f2fs_sb_info *sbi);
 int f2fs_remove_inode_page(struct inode *inode);
 struct page *f2fs_new_inode_page(struct inode *inode);
 struct page *f2fs_new_node_page(struct dnode_of_data *dn, unsigned int ofs);
@@ -3567,6 +3538,7 @@ int f2fs_recover_xattr_data(struct inode *inode, struct page *page);
 int f2fs_recover_inode_page(struct f2fs_sb_info *sbi, struct page *page);
 int f2fs_restore_node_summary(struct f2fs_sb_info *sbi,
 			unsigned int segno, struct f2fs_summary_block *sum);
+void f2fs_enable_nat_bits(struct f2fs_sb_info *sbi);
 int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
 int f2fs_build_node_manager(struct f2fs_sb_info *sbi);
 void f2fs_destroy_node_manager(struct f2fs_sb_info *sbi);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 161173de5a2d..4b4a82cacf9a 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -2212,6 +2212,24 @@ static void __move_free_nid(struct f2fs_sb_info *sbi, struct free_nid *i,
 	}
 }
 
+bool f2fs_nat_bitmap_enabled(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	unsigned int i;
+	bool ret = true;
+
+	down_read(&nm_i->nat_tree_lock);
+	for (i = 0; i < nm_i->nat_blocks; i++) {
+		if (!test_bit_le(i, nm_i->nat_block_bitmap)) {
+			ret = false;
+			break;
+		}
+	}
+	up_read(&nm_i->nat_tree_lock);
+
+	return ret;
+}
+
 static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
 							bool set, bool build)
 {
@@ -2883,7 +2901,23 @@ static void __adjust_nat_entry_set(struct nat_entry_set *nes,
 	list_add_tail(&nes->set_list, head);
 }
 
-static void __update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
+static void __update_nat_bits(struct f2fs_nm_info *nm_i, unsigned int nat_ofs,
+							unsigned int valid)
+{
+	if (valid == 0) {
+		__set_bit_le(nat_ofs, nm_i->empty_nat_bits);
+		__clear_bit_le(nat_ofs, nm_i->full_nat_bits);
+		return;
+	}
+
+	__clear_bit_le(nat_ofs, nm_i->empty_nat_bits);
+	if (valid == NAT_ENTRY_PER_BLOCK)
+		__set_bit_le(nat_ofs, nm_i->full_nat_bits);
+	else
+		__clear_bit_le(nat_ofs, nm_i->full_nat_bits);
+}
+
+static void update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
 						struct page *page)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
@@ -2892,7 +2926,7 @@ static void __update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
 	int valid = 0;
 	int i = 0;
 
-	if (!enabled_nat_bits(sbi, NULL))
+	if (!is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG))
 		return;
 
 	if (nat_index == 0) {
@@ -2903,17 +2937,36 @@ static void __update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
 		if (le32_to_cpu(nat_blk->entries[i].block_addr) != NULL_ADDR)
 			valid++;
 	}
-	if (valid == 0) {
-		__set_bit_le(nat_index, nm_i->empty_nat_bits);
-		__clear_bit_le(nat_index, nm_i->full_nat_bits);
-		return;
+
+	__update_nat_bits(nm_i, nat_index, valid);
+}
+
+void f2fs_enable_nat_bits(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	unsigned int nat_ofs;
+
+	down_read(&nm_i->nat_tree_lock);
+
+	for (nat_ofs = 0; nat_ofs < nm_i->nat_blocks; nat_ofs++) {
+		unsigned int valid = 0, nid_ofs = 0;
+
+		/* handle nid zero due to it should never be used */
+		if (unlikely(nat_ofs == 0)) {
+			valid = 1;
+			nid_ofs = 1;
+		}
+
+		for (; nid_ofs < NAT_ENTRY_PER_BLOCK; nid_ofs++) {
+			if (!test_bit_le(nid_ofs,
+					nm_i->free_nid_bitmap[nat_ofs]))
+				valid++;
+		}
+
+		__update_nat_bits(nm_i, nat_ofs, valid);
 	}
 
-	__clear_bit_le(nat_index, nm_i->empty_nat_bits);
-	if (valid == NAT_ENTRY_PER_BLOCK)
-		__set_bit_le(nat_index, nm_i->full_nat_bits);
-	else
-		__clear_bit_le(nat_index, nm_i->full_nat_bits);
+	up_read(&nm_i->nat_tree_lock);
 }
 
 static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
@@ -2932,7 +2985,7 @@ static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
 	 * #1, flush nat entries to journal in current hot data summary block.
 	 * #2, flush nat entries to nat page.
 	 */
-	if (enabled_nat_bits(sbi, cpc) ||
+	if ((cpc->reason & CP_UMOUNT) ||
 		!__has_cursum_space(journal, set->entry_cnt, NAT_JOURNAL))
 		to_journal = false;
 
@@ -2979,7 +3032,7 @@ static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
 	if (to_journal) {
 		up_write(&curseg->journal_rwsem);
 	} else {
-		__update_nat_bits(sbi, start_nid, page);
+		update_nat_bits(sbi, start_nid, page);
 		f2fs_put_page(page, 1);
 	}
 
@@ -3010,7 +3063,7 @@ int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	 * during unmount, let's flush nat_bits before checking
 	 * nat_cnt[DIRTY_NAT].
 	 */
-	if (enabled_nat_bits(sbi, cpc)) {
+	if (cpc->reason & CP_UMOUNT) {
 		down_write(&nm_i->nat_tree_lock);
 		remove_nats_in_journal(sbi);
 		up_write(&nm_i->nat_tree_lock);
@@ -3026,7 +3079,7 @@ int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	 * entries, remove all entries from journal and merge them
 	 * into nat entry set.
 	 */
-	if (enabled_nat_bits(sbi, cpc) ||
+	if (cpc->reason & CP_UMOUNT ||
 		!__has_cursum_space(journal,
 			nm_i->nat_cnt[DIRTY_NAT], NAT_JOURNAL))
 		remove_nats_in_journal(sbi);
@@ -3063,15 +3116,18 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
 	__u64 cp_ver = cur_cp_version(ckpt);
 	block_t nat_bits_addr;
 
-	if (!enabled_nat_bits(sbi, NULL))
-		return 0;
-
 	nm_i->nat_bits_blocks = F2FS_BLK_ALIGN((nat_bits_bytes << 1) + 8);
 	nm_i->nat_bits = f2fs_kvzalloc(sbi,
 			nm_i->nat_bits_blocks << F2FS_BLKSIZE_BITS, GFP_KERNEL);
 	if (!nm_i->nat_bits)
 		return -ENOMEM;
 
+	nm_i->full_nat_bits = nm_i->nat_bits + 8;
+	nm_i->empty_nat_bits = nm_i->full_nat_bits + nat_bits_bytes;
+
+	if (!is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG))
+		return 0;
+
 	nat_bits_addr = __start_cp_addr(sbi) + sbi->blocks_per_seg -
 						nm_i->nat_bits_blocks;
 	for (i = 0; i < nm_i->nat_bits_blocks; i++) {
@@ -3088,13 +3144,12 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
 
 	cp_ver |= (cur_cp_crc(ckpt) << 32);
 	if (cpu_to_le64(cp_ver) != *(__le64 *)nm_i->nat_bits) {
-		disable_nat_bits(sbi, true);
+		clear_ckpt_flags(sbi, CP_NAT_BITS_FLAG);
+		f2fs_notice(sbi, "Disable nat_bits due to incorrect cp_ver (%llu, %llu)",
+			cp_ver, le64_to_cpu(*(__le64 *)nm_i->nat_bits));
 		return 0;
 	}
 
-	nm_i->full_nat_bits = nm_i->nat_bits + 8;
-	nm_i->empty_nat_bits = nm_i->full_nat_bits + nat_bits_bytes;
-
 	f2fs_notice(sbi, "Found nat_bits in checkpoint");
 	return 0;
 }
@@ -3105,7 +3160,7 @@ static inline void load_free_nid_bitmap(struct f2fs_sb_info *sbi)
 	unsigned int i = 0;
 	nid_t nid, last_nid;
 
-	if (!enabled_nat_bits(sbi, NULL))
+	if (!is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG))
 		return;
 
 	for (i = 0; i < nm_i->nat_blocks; i++) {
-- 
2.32.0