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Date:   Wed, 26 Dec 2018 15:10:09 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, chao@kernel.org
Subject: Re: [PATCH v2] f2fs: rebuild nat_bits during umount
Message-ID: <20181226231009.GB54766@jaegeuk-macbookpro.roam.corp.google.com>
References: <20181213085020.49241-1-yuchao0@huawei.com>
 <461b1a02-977a-00a7-cf5b-4869355fa8f0@huawei.com>
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On 12/24, Chao Yu wrote:
> On 2018/12/13 16:50, Chao Yu wrote:
> > 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.
> 
> Jaegeuk,
> 
> Could you please have a try with this patch?
> 
> I just did xfstest on it with below method, and there is no data corruption
> reported from fsck:

Yup, will do later.

> 
> - let fill_super preload all NAT blocks to enable free_nid_bitmap entirely.
> - don't add nat_bits during mkfs image.
> 
> Thanks,
> 
> > 
> > Signed-off-by: Chao Yu <yuchao0@huawei.com>
> > ---
> > v2:
> > - fix bugs in f2fs_enable_nat_bits()
> > - add kmsg to record nat_bits {en,dis}abling operations
> > - fix to validate {full,empty}_nat_bits in __get_nat_bitmaps()
> > 
> >  fs/f2fs/checkpoint.c | 20 +++++++++---
> >  fs/f2fs/f2fs.h       | 21 ++-----------
> >  fs/f2fs/node.c       | 72 +++++++++++++++++++++++++++++++++++++++-----
> >  3 files changed, 82 insertions(+), 31 deletions(-)
> > 
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index 623536b8e0c0..fa0eb56f1703 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -1225,12 +1225,22 @@ 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_msg(sbi->sb, KERN_NOTICE,
> > +				"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_msg(sbi->sb, KERN_NOTICE,
> > +				"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);
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 7cec897146a3..869a36b6a28f 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1618,25 +1618,6 @@ 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;
> > -
> > -	/*
> > -	 * 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);
> > -	kfree(NM_I(sbi)->nat_bits);
> > -	NM_I(sbi)->nat_bits = NULL;
> > -	if (lock)
> > -		spin_unlock_irqrestore(&sbi->cp_lock, flags);
> > -}
> > -
> >  static inline bool enabled_nat_bits(struct f2fs_sb_info *sbi,
> >  					struct cp_control *cpc)
> >  {
> > @@ -2952,6 +2933,7 @@ 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);
> > @@ -2975,6 +2957,7 @@ 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 30a4427aaa94..9f55f2cb0dff 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -2036,6 +2036,24 @@ 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)
> >  {
> > @@ -2720,6 +2738,43 @@ static void __update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
> >  		__clear_bit_le(nat_index, nm_i->full_nat_bits);
> >  }
> >  
> > +void f2fs_enable_nat_bits(struct f2fs_sb_info *sbi)
> > +{
> > +	struct f2fs_nm_info *nm_i = NM_I(sbi);
> > +	int nat_ofs;
> > +
> > +	down_read(&nm_i->nat_tree_lock);
> > +
> > +	for (nat_ofs = 0; nat_ofs < nm_i->nat_blocks; nat_ofs++) {
> > +		int valid = 0, nid_ofs = 0;
> > +
> > +		if (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++;
> > +		}
> > +
> > +		if (valid == 0) {
> > +			__set_bit_le(nat_ofs, nm_i->empty_nat_bits);
> > +			__clear_bit_le(nat_ofs, nm_i->full_nat_bits);
> > +			continue;
> > +		}
> > +
> > +		__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);
> > +	}
> > +
> > +	up_read(&nm_i->nat_tree_lock);
> > +}
> > +
> >  static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
> >  		struct nat_entry_set *set, struct cp_control *cpc)
> >  {
> > @@ -2862,15 +2917,18 @@ 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_kzalloc(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 (!enabled_nat_bits(sbi, NULL))
> > +		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++) {
> > @@ -2887,13 +2945,13 @@ 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_msg(sbi->sb, KERN_NOTICE,
> > +			"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_msg(sbi->sb, KERN_NOTICE, "Found nat_bits in checkpoint");
> >  	return 0;
> >  }
> >