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Subject: Re: [PATCH v4 RESEND] f2fs: fix out-of-free problem caused by atomic
 write
To:     <jaegeuk@kernel.org>, <chao@kernel.org>, <yuchao0@huawei.com>,
        <yunlong.song@icloud.com>
CC:     <miaoxie@huawei.com>, <bintian.wang@huawei.com>,
        <linux-fsdevel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>
References: <1510880065-148982-1-git-send-email-yunlong.song@huawei.com>
From:   Yunlong Song <yunlong.song@huawei.com>
Message-ID: <75e9ab35-f037-ecfd-4e0a-4f8be968e56a@huawei.com>
Date:   Wed, 22 Nov 2017 11:50:31 +0800
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ping again...

On 2017/11/17 8:54, Yunlong Song wrote:
> f2fs_balance_fs only actives once in the commit_inmem_pages, but there
> are more than one page to commit, so all the other pages will miss the
> check. This will lead to out-of-free problem when commit a very large
> file. However, we cannot do f2fs_balance_fs for each inmem page, since
> this will break atomicity. As a result, we should do f2fs_balance_fs
> for all the inmem pages together.
>
> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> ---
>   fs/f2fs/debug.c   |  5 +++--
>   fs/f2fs/f2fs.h    | 26 ++++++++++++++++++++++++--
>   fs/f2fs/segment.c | 30 ++++++++++++++++++++++++------
>   fs/f2fs/segment.h |  4 +++-
>   4 files changed, 54 insertions(+), 11 deletions(-)
>
> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
> index f7eec50..41c47c4 100644
> --- a/fs/f2fs/debug.c
> +++ b/fs/f2fs/debug.c
> @@ -50,6 +50,7 @@ static void update_general_status(struct f2fs_sb_info *sbi)
>   	si->ndirty_files = sbi->ndirty_inode[FILE_INODE];
>   	si->ndirty_all = sbi->ndirty_inode[DIRTY_META];
>   	si->inmem_pages = get_pages(sbi, F2FS_INMEM_PAGES);
> +	si->inmem_commit_pages = get_pages(sbi, F2FS_INMEM_COMMIT_PAGES);
>   	si->aw_cnt = atomic_read(&sbi->aw_cnt);
>   	si->vw_cnt = atomic_read(&sbi->vw_cnt);
>   	si->max_aw_cnt = atomic_read(&sbi->max_aw_cnt);
> @@ -360,9 +361,9 @@ static int stat_show(struct seq_file *s, void *v)
>   			   si->nr_discarding, si->nr_discarded,
>   			   si->nr_discard_cmd, si->undiscard_blks);
>   		seq_printf(s, "  - inmem: %4d, atomic IO: %4d (Max. %4d), "
> -			"volatile IO: %4d (Max. %4d)\n",
> +			"volatile IO: %4d (Max. %4d), commit: %4d\n",
>   			   si->inmem_pages, si->aw_cnt, si->max_aw_cnt,
> -			   si->vw_cnt, si->max_vw_cnt);
> +			   si->vw_cnt, si->max_vw_cnt, si->inmem_commit_pages);
>   		seq_printf(s, "  - nodes: %4d in %4d\n",
>   			   si->ndirty_node, si->node_pages);
>   		seq_printf(s, "  - dents: %4d in dirs:%4d (%4d)\n",
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 13a96b8..749bdb6 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -610,6 +610,7 @@ struct f2fs_inode_info {
>   	struct list_head inmem_pages;	/* inmemory pages managed by f2fs */
>   	struct task_struct *inmem_task;	/* store inmemory task */
>   	struct mutex inmem_lock;	/* lock for inmemory pages */
> +	unsigned long inmem_blocks;	/* inmemory blocks */
>   	struct extent_tree *extent_tree;	/* cached extent_tree entry */
>   	struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */
>   	struct rw_semaphore i_mmap_sem;
> @@ -863,6 +864,7 @@ enum count_type {
>   	F2FS_DIRTY_NODES,
>   	F2FS_DIRTY_META,
>   	F2FS_INMEM_PAGES,
> +	F2FS_INMEM_COMMIT_PAGES,
>   	F2FS_DIRTY_IMETA,
>   	F2FS_WB_CP_DATA,
>   	F2FS_WB_DATA,
> @@ -1600,7 +1602,21 @@ static inline void inc_page_count(struct f2fs_sb_info *sbi, int count_type)
>   	atomic_inc(&sbi->nr_pages[count_type]);
>   
>   	if (count_type == F2FS_DIRTY_DATA || count_type == F2FS_INMEM_PAGES ||
> -		count_type == F2FS_WB_CP_DATA || count_type == F2FS_WB_DATA)
> +		count_type == F2FS_WB_CP_DATA || count_type == F2FS_WB_DATA ||
> +		count_type == F2FS_INMEM_COMMIT_PAGES)
> +		return;
> +
> +	set_sbi_flag(sbi, SBI_IS_DIRTY);
> +}
> +
> +static inline void inc_pages_count(struct f2fs_sb_info *sbi, int count_type,
> +					int pages)
> +{
> +	atomic_add(pages, &sbi->nr_pages[count_type]);
> +
> +	if (count_type == F2FS_DIRTY_DATA || count_type == F2FS_INMEM_PAGES ||
> +		count_type == F2FS_WB_CP_DATA || count_type == F2FS_WB_DATA ||
> +		count_type == F2FS_INMEM_COMMIT_PAGES)
>   		return;
>   
>   	set_sbi_flag(sbi, SBI_IS_DIRTY);
> @@ -1618,6 +1634,12 @@ static inline void dec_page_count(struct f2fs_sb_info *sbi, int count_type)
>   	atomic_dec(&sbi->nr_pages[count_type]);
>   }
>   
> +static inline void dec_pages_count(struct f2fs_sb_info *sbi, int count_type,
> +					int pages)
> +{
> +	atomic_sub(pages, &sbi->nr_pages[count_type]);
> +}
> +
>   static inline void inode_dec_dirty_pages(struct inode *inode)
>   {
>   	if (!S_ISDIR(inode->i_mode) && !S_ISREG(inode->i_mode) &&
> @@ -2716,7 +2738,7 @@ struct f2fs_stat_info {
>   	unsigned long long hit_total, total_ext;
>   	int ext_tree, zombie_tree, ext_node;
>   	int ndirty_node, ndirty_dent, ndirty_meta, ndirty_data, ndirty_imeta;
> -	int inmem_pages;
> +	int inmem_pages, inmem_commit_pages;
>   	unsigned int ndirty_dirs, ndirty_files, ndirty_all;
>   	int nats, dirty_nats, sits, dirty_sits;
>   	int free_nids, avail_nids, alloc_nids;
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 46dfbca..2ff1bba4 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -174,6 +174,8 @@ bool need_SSR(struct f2fs_sb_info *sbi)
>   	int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
>   	int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
>   	int imeta_secs = get_blocktype_secs(sbi, F2FS_DIRTY_IMETA);
> +	int inmem_commit_secs = get_blocktype_secs(sbi,
> +						F2FS_INMEM_COMMIT_PAGES);
>   
>   	if (test_opt(sbi, LFS))
>   		return false;
> @@ -181,7 +183,7 @@ bool need_SSR(struct f2fs_sb_info *sbi)
>   		return true;
>   
>   	return free_sections(sbi) <= (node_secs + 2 * dent_secs + imeta_secs +
> -						2 * reserved_sections(sbi));
> +				inmem_commit_secs + 2 * reserved_sections(sbi));
>   }
>   
>   void register_inmem_page(struct inode *inode, struct page *page)
> @@ -210,6 +212,7 @@ void register_inmem_page(struct inode *inode, struct page *page)
>   		list_add_tail(&fi->inmem_ilist, &sbi->inode_list[ATOMIC_FILE]);
>   	spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
>   	inc_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
> +	fi->inmem_blocks++;
>   	mutex_unlock(&fi->inmem_lock);
>   
>   	trace_f2fs_register_inmem_page(page, INMEM);
> @@ -221,6 +224,7 @@ static int __revoke_inmem_pages(struct inode *inode,
>   	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>   	struct inmem_pages *cur, *tmp;
>   	int err = 0;
> +	struct f2fs_inode_info *fi = F2FS_I(inode);
>   
>   	list_for_each_entry_safe(cur, tmp, head, list) {
>   		struct page *page = cur->page;
> @@ -263,6 +267,7 @@ static int __revoke_inmem_pages(struct inode *inode,
>   		list_del(&cur->list);
>   		kmem_cache_free(inmem_entry_slab, cur);
>   		dec_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
> +		fi->inmem_blocks--;
>   	}
>   	return err;
>   }
> @@ -302,6 +307,10 @@ void drop_inmem_pages(struct inode *inode)
>   	if (!list_empty(&fi->inmem_ilist))
>   		list_del_init(&fi->inmem_ilist);
>   	spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
> +	if (fi->inmem_blocks) {
> +		f2fs_bug_on(sbi, 1);
> +		fi->inmem_blocks = 0;
> +	}
>   	mutex_unlock(&fi->inmem_lock);
>   
>   	clear_inode_flag(inode, FI_ATOMIC_FILE);
> @@ -326,6 +335,7 @@ void drop_inmem_page(struct inode *inode, struct page *page)
>   
>   	f2fs_bug_on(sbi, !cur || cur->page != page);
>   	list_del(&cur->list);
> +	fi->inmem_blocks--;
>   	mutex_unlock(&fi->inmem_lock);
>   
>   	dec_page_count(sbi, F2FS_INMEM_PAGES);
> @@ -354,7 +364,7 @@ static int __commit_inmem_pages(struct inode *inode,
>   		.io_type = FS_DATA_IO,
>   	};
>   	pgoff_t last_idx = ULONG_MAX;
> -	int err = 0;
> +	int err = 0, inmem_blocks = fi->inmem_blocks;
>   
>   	list_for_each_entry_safe(cur, tmp, &fi->inmem_pages, list) {
>   		struct page *page = cur->page;
> @@ -390,6 +400,8 @@ static int __commit_inmem_pages(struct inode *inode,
>   		}
>   		unlock_page(page);
>   		list_move_tail(&cur->list, revoke_list);
> +		dec_page_count(sbi, F2FS_INMEM_COMMIT_PAGES);
> +		inmem_blocks--;
>   	}
>   
>   	if (last_idx != ULONG_MAX)
> @@ -397,6 +409,8 @@ static int __commit_inmem_pages(struct inode *inode,
>   
>   	if (!err)
>   		__revoke_inmem_pages(inode, revoke_list, false, false);
> +	else
> +		dec_pages_count(sbi, F2FS_INMEM_COMMIT_PAGES, inmem_blocks);
>   
>   	return err;
>   }
> @@ -409,12 +423,12 @@ int commit_inmem_pages(struct inode *inode)
>   	int err;
>   
>   	INIT_LIST_HEAD(&revoke_list);
> +	set_inode_flag(inode, FI_ATOMIC_COMMIT);
> +	mutex_lock(&fi->inmem_lock);
> +	inc_pages_count(sbi, F2FS_INMEM_COMMIT_PAGES, fi->inmem_blocks);
>   	f2fs_balance_fs(sbi, true);
>   	f2fs_lock_op(sbi);
>   
> -	set_inode_flag(inode, FI_ATOMIC_COMMIT);
> -
> -	mutex_lock(&fi->inmem_lock);
>   	err = __commit_inmem_pages(inode, &revoke_list);
>   	if (err) {
>   		int ret;
> @@ -437,11 +451,15 @@ int commit_inmem_pages(struct inode *inode)
>   	if (!list_empty(&fi->inmem_ilist))
>   		list_del_init(&fi->inmem_ilist);
>   	spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
> +	if (fi->inmem_blocks) {
> +		f2fs_bug_on(sbi, 1);
> +		fi->inmem_blocks = 0;
> +	}
> +	f2fs_unlock_op(sbi);
>   	mutex_unlock(&fi->inmem_lock);
>   
>   	clear_inode_flag(inode, FI_ATOMIC_COMMIT);
>   
> -	f2fs_unlock_op(sbi);
>   	return err;
>   }
>   
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 8d93652..f3885de 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -503,12 +503,14 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi,
>   	int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
>   	int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
>   	int imeta_secs = get_blocktype_secs(sbi, F2FS_DIRTY_IMETA);
> +	int inmem_commit_secs = get_blocktype_secs(sbi,
> +						F2FS_INMEM_COMMIT_PAGES);
>   
>   	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
>   		return false;
>   
>   	return (free_sections(sbi) + freed) <=
> -		(node_secs + 2 * dent_secs + imeta_secs +
> +		(node_secs + 2 * dent_secs + imeta_secs + inmem_commit_secs +
>   		reserved_sections(sbi) + needed);
>   }
>   

-- 
Thanks,
Yunlong Song


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