Re: [f2fs-dev] [PATCH] f2fs: cover update_free_nid_bitmap with free_list_lock

[Kinglong Mee]

On 3/13/2017 20:10, Chao Yu wrote:
> free_nid_bitmap and free_nid_count in update_free_nid_bitmap should be
> updated atomically, use free_list_lock cover them to avoid race in

nid_list_lock?

Reviewed-by: Kinglong Mee <kinglongmee@xxxxxxxxx>

> concurrent scenario.
> 
> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> ---
>  fs/f2fs/f2fs.h |  1 -
>  fs/f2fs/node.c | 27 +++++++++++----------------
>  2 files changed, 11 insertions(+), 17 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 843ce39502bc..d905e53ba524 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -561,7 +561,6 @@ struct f2fs_nm_info {
>  	unsigned char (*free_nid_bitmap)[NAT_ENTRY_BITMAP_SIZE];
>  	unsigned char *nat_block_bitmap;
>  	unsigned short *free_nid_count;	/* free nid count of NAT block */
> -	spinlock_t free_nid_lock;	/* protect updating of nid count */
>  
>  	/* for checkpoint */
>  	char *nat_bitmap;		/* NAT bitmap pointer */
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 11df8ab32478..3bfffd744f87 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1815,7 +1815,7 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
>  }
>  
>  static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
> -			bool set, bool build, bool locked)
> +							bool set, bool build)
>  {
>  	struct f2fs_nm_info *nm_i = NM_I(sbi);
>  	unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid);
> @@ -1829,14 +1829,10 @@ static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
>  	else
>  		__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
>  
> -	if (!locked)
> -		spin_lock(&nm_i->free_nid_lock);
>  	if (set)
>  		nm_i->free_nid_count[nat_ofs]++;
>  	else if (!build)
>  		nm_i->free_nid_count[nat_ofs]--;
> -	if (!locked)
> -		spin_unlock(&nm_i->free_nid_lock);
>  }
>  
>  static void scan_nat_page(struct f2fs_sb_info *sbi,
> @@ -1865,7 +1861,9 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
>  		f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
>  		if (blk_addr == NULL_ADDR)
>  			freed = add_free_nid(sbi, start_nid, true);
> -		update_free_nid_bitmap(sbi, start_nid, freed, true, false);
> +		spin_lock(&NM_I(sbi)->nid_list_lock);
> +		update_free_nid_bitmap(sbi, start_nid, freed, true);
> +		spin_unlock(&NM_I(sbi)->nid_list_lock);
>  	}
>  }
>  
> @@ -2020,7 +2018,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
>  		__insert_nid_to_list(sbi, i, ALLOC_NID_LIST, false);
>  		nm_i->available_nids--;
>  
> -		update_free_nid_bitmap(sbi, *nid, false, false, false);
> +		update_free_nid_bitmap(sbi, *nid, false, false);
>  
>  		spin_unlock(&nm_i->nid_list_lock);
>  		return true;
> @@ -2076,7 +2074,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
>  
>  	nm_i->available_nids++;
>  
> -	update_free_nid_bitmap(sbi, nid, true, false, false);
> +	update_free_nid_bitmap(sbi, nid, true, false);
>  
>  	spin_unlock(&nm_i->nid_list_lock);
>  
> @@ -2406,11 +2404,11 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>  			add_free_nid(sbi, nid, false);
>  			spin_lock(&NM_I(sbi)->nid_list_lock);
>  			NM_I(sbi)->available_nids++;
> -			update_free_nid_bitmap(sbi, nid, true, false, false);
> +			update_free_nid_bitmap(sbi, nid, true, false);
>  			spin_unlock(&NM_I(sbi)->nid_list_lock);
>  		} else {
>  			spin_lock(&NM_I(sbi)->nid_list_lock);
> -			update_free_nid_bitmap(sbi, nid, false, false, false);
> +			update_free_nid_bitmap(sbi, nid, false, false);
>  			spin_unlock(&NM_I(sbi)->nid_list_lock);
>  		}
>  	}
> @@ -2535,10 +2533,10 @@ inline void load_free_nid_bitmap(struct f2fs_sb_info *sbi)
>  		nid = i * NAT_ENTRY_PER_BLOCK;
>  		last_nid = (i + 1) * NAT_ENTRY_PER_BLOCK;
>  
> -		spin_lock(&nm_i->free_nid_lock);
> +		spin_lock(&NM_I(sbi)->nid_list_lock);
>  		for (; nid < last_nid; nid++)
> -			update_free_nid_bitmap(sbi, nid, true, true, true);
> -		spin_unlock(&nm_i->free_nid_lock);
> +			update_free_nid_bitmap(sbi, nid, true, true);
> +		spin_unlock(&NM_I(sbi)->nid_list_lock);
>  	}
>  
>  	for (i = 0; i < nm_i->nat_blocks; i++) {
> @@ -2629,9 +2627,6 @@ static int init_free_nid_cache(struct f2fs_sb_info *sbi)
>  					sizeof(unsigned short), GFP_KERNEL);
>  	if (!nm_i->free_nid_count)
>  		return -ENOMEM;
> -
> -	spin_lock_init(&nm_i->free_nid_lock);
> -
>  	return 0;
>  }
>  
>