Re: [PATCH 2/3] f2fs: fix conditions to remain recovery information in f2fs_sync_file

[Chao Yu <chao2.yu@samsung.com>]

Hi Jaegeuk, Huang,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Thursday, September 18, 2014 1:51 PM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim; Huang Ying
> Subject: [f2fs-dev] [PATCH 2/3] f2fs: fix conditions to remain recovery information in
> f2fs_sync_file
> 
> This patch revisited whole the recovery information during the f2fs_sync_file.
> 
> In this patch, there are three information to make a decision.
> 
> a) IS_CHECKPOINTED,	/* is it checkpointed before? */
> b) HAS_FSYNCED_INODE,	/* is the inode fsynced before? */
> c) HAS_LAST_FSYNC,	/* has the latest node fsync mark? */
> 
> And, the scenarios for our rule are based on:
> 
> [Term] F: fsync_mark, D: dentry_mark
> 
> 1. inode(x) | CP | inode(x) | dnode(F)
> 2. inode(x) | CP | inode(F) | dnode(F)
> 3. inode(x) | CP | dnode(F) | inode(x) | inode(F)
> 4. inode(x) | CP | dnode(F) | inode(F)
> 5. CP | inode(x) | dnode(F) | inode(DF)
> 6. CP | inode(DF) | dnode(F)
> 7. CP | dnode(F) | inode(DF)
> 8. CP | dnode(F) | inode(x) | inode(DF)

No sure, do we missed these cases:
inode(x) | CP | inode(F) | dnode(x) -> write inode(F)
CP | inode(DF) | dnode(x) -> write inode(F)

In these cases we will write another inode with fsync flag because our last
dnode is written out to disk by bdi-flusher (HAS_LAST_FSYNC is not marked). But
this appended inode is not useful.

AFAIK, HAS_LAST_FSYNC(AKA fsync_done) is introduced in commit 479f40c44ae3
("f2fs: skip unnecessary node writes during fsync") to avoid writting multiple
unneeded inode page by multiple redundant fsync calls. But for now, its role can
be taken by HAS_FSYNCED_INODE.
So, can we remove this flag to simplify our logic of fsync flow?

Then in fsync flow, the rule can be:
If CPed before, there must be a inode(F) written in warm node chain;
If not CPed before, there must be a inode(DF) written in warm node chain.

Thanks,
Yu

> 
> For example, #3, the three conditions should be changed as follows.
> 
>    inode(x) | CP | dnode(F) | inode(x) | inode(F)
> a)    x       o      o          o          o
> b)    x       x      x          x          o
> c)    x       o      o          x          o
> 
> If f2fs_sync_file stops   ------^,
>  it should write inode(F)    --------------^
> 
> So, the need_inode_block_update should return true, since
>  c) get_nat_flag(e, HAS_LAST_FSYNC), is false.
> 
> For example, #8,
>       CP | alloc | dnode(F) | inode(x) | inode(DF)
> a)    o      x        x          x          x
> b)    x               x          x          o
> c)    o               o          x          o
> 
> If f2fs_sync_file stops   -------^,
>  it should write inode(DF)    --------------^
> 
> Note that, the roll-forward policy should follow this rule, which means,
> if there are any missing blocks, we doesn't need to recover that inode.
> 
> Signed-off-by: Huang Ying <ying.huang@intel.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/data.c |  3 ---
>  fs/f2fs/f2fs.h |  6 +++---
>  fs/f2fs/file.c | 10 ++++++----
>  fs/f2fs/node.c | 56 +++++++++++++++++++++++++++++++++++---------------------
>  fs/f2fs/node.h | 21 ++++++++++++---------
>  5 files changed, 56 insertions(+), 40 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 0e37658..fdc3dbe 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1089,9 +1089,6 @@ static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
>  	if (check_direct_IO(inode, rw, iter, offset))
>  		return 0;
> 
> -	/* clear fsync mark to recover these blocks */
> -	fsync_mark_clear(F2FS_I_SB(inode), inode->i_ino);
> -
>  	trace_f2fs_direct_IO_enter(inode, offset, count, rw);
> 
>  	err = blockdev_direct_IO(rw, iocb, inode, iter, offset, get_data_block);
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 9fc1bcd..fd44083 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1224,9 +1224,9 @@ struct dnode_of_data;
>  struct node_info;
> 
>  bool available_free_memory(struct f2fs_sb_info *, int);
> -int is_checkpointed_node(struct f2fs_sb_info *, nid_t);
> -bool fsync_mark_done(struct f2fs_sb_info *, nid_t);
> -void fsync_mark_clear(struct f2fs_sb_info *, nid_t);
> +bool is_checkpointed_node(struct f2fs_sb_info *, nid_t);
> +bool has_fsynced_inode(struct f2fs_sb_info *, nid_t);
> +bool need_inode_block_update(struct f2fs_sb_info *, nid_t);
>  void get_node_info(struct f2fs_sb_info *, nid_t, struct node_info *);
>  int get_dnode_of_data(struct dnode_of_data *, pgoff_t, int);
>  int truncate_inode_blocks(struct inode *, pgoff_t);
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index af06e22..3035c79 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -207,15 +207,17 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int
> datasync)
>  			up_write(&fi->i_sem);
>  		}
>  	} else {
> -		/* if there is no written node page, write its inode page */
> -		while (!sync_node_pages(sbi, ino, &wbc)) {
> -			if (fsync_mark_done(sbi, ino))
> -				goto out;
> +sync_nodes:
> +		sync_node_pages(sbi, ino, &wbc);
> +
> +		if (need_inode_block_update(sbi, ino)) {
>  			mark_inode_dirty_sync(inode);
>  			ret = f2fs_write_inode(inode, NULL);
>  			if (ret)
>  				goto out;
> +			goto sync_nodes;
>  		}
> +
>  		ret = wait_on_node_pages_writeback(sbi, ino);
>  		if (ret)
>  			goto out;
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index d19d6b1..7a2d9c9 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -123,44 +123,48 @@ static void __del_from_nat_cache(struct f2fs_nm_info *nm_i, struct
> nat_entry *e)
>  	kmem_cache_free(nat_entry_slab, e);
>  }
> 
> -int is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
> +bool is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
>  {
>  	struct f2fs_nm_info *nm_i = NM_I(sbi);
>  	struct nat_entry *e;
> -	int is_cp = 1;
> +	bool is_cp = true;
> 
>  	read_lock(&nm_i->nat_tree_lock);
>  	e = __lookup_nat_cache(nm_i, nid);
>  	if (e && !get_nat_flag(e, IS_CHECKPOINTED))
> -		is_cp = 0;
> +		is_cp = false;
>  	read_unlock(&nm_i->nat_tree_lock);
>  	return is_cp;
>  }
> 
> -bool fsync_mark_done(struct f2fs_sb_info *sbi, nid_t nid)
> +bool has_fsynced_inode(struct f2fs_sb_info *sbi, nid_t ino)
>  {
>  	struct f2fs_nm_info *nm_i = NM_I(sbi);
>  	struct nat_entry *e;
> -	bool fsync_done = false;
> +	bool fsynced = false;
> 
>  	read_lock(&nm_i->nat_tree_lock);
> -	e = __lookup_nat_cache(nm_i, nid);
> -	if (e)
> -		fsync_done = get_nat_flag(e, HAS_FSYNC_MARK);
> +	e = __lookup_nat_cache(nm_i, ino);
> +	if (e && get_nat_flag(e, HAS_FSYNCED_INODE))
> +		fsynced = true;
>  	read_unlock(&nm_i->nat_tree_lock);
> -	return fsync_done;
> +	return fsynced;
>  }
> 
> -void fsync_mark_clear(struct f2fs_sb_info *sbi, nid_t nid)
> +bool need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino)
>  {
>  	struct f2fs_nm_info *nm_i = NM_I(sbi);
>  	struct nat_entry *e;
> +	bool need_update = true;
> 
> -	write_lock(&nm_i->nat_tree_lock);
> -	e = __lookup_nat_cache(nm_i, nid);
> -	if (e)
> -		set_nat_flag(e, HAS_FSYNC_MARK, false);
> -	write_unlock(&nm_i->nat_tree_lock);
> +	read_lock(&nm_i->nat_tree_lock);
> +	e = __lookup_nat_cache(nm_i, ino);
> +	if (e && get_nat_flag(e, HAS_LAST_FSYNC) &&
> +			(get_nat_flag(e, IS_CHECKPOINTED) ||
> +			 get_nat_flag(e, HAS_FSYNCED_INODE)))
> +		need_update = false;
> +	read_unlock(&nm_i->nat_tree_lock);
> +	return need_update;
>  }
> 
>  static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid)
> @@ -176,7 +180,7 @@ static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t
> nid)
>  	}
>  	memset(new, 0, sizeof(struct nat_entry));
>  	nat_set_nid(new, nid);
> -	set_nat_flag(new, IS_CHECKPOINTED, true);
> +	nat_reset_flag(new);
>  	list_add_tail(&new->list, &nm_i->nat_entries);
>  	nm_i->nat_cnt++;
>  	return new;
> @@ -244,12 +248,17 @@ retry:
> 
>  	/* change address */
>  	nat_set_blkaddr(e, new_blkaddr);
> +	if (new_blkaddr == NEW_ADDR || new_blkaddr == NULL_ADDR)
> +		set_nat_flag(e, IS_CHECKPOINTED, false);
>  	__set_nat_cache_dirty(nm_i, e);
> 
>  	/* update fsync_mark if its inode nat entry is still alive */
>  	e = __lookup_nat_cache(nm_i, ni->ino);
> -	if (e)
> -		set_nat_flag(e, HAS_FSYNC_MARK, fsync_done);
> +	if (e) {
> +		if (fsync_done && ni->nid == ni->ino)
> +			set_nat_flag(e, HAS_FSYNCED_INODE, true);
> +		set_nat_flag(e, HAS_LAST_FSYNC, fsync_done);
> +	}
>  	write_unlock(&nm_i->nat_tree_lock);
>  }
> 
> @@ -1121,10 +1130,14 @@ continue_unlock:
> 
>  			/* called by fsync() */
>  			if (ino && IS_DNODE(page)) {
> -				int mark = !is_checkpointed_node(sbi, ino);
>  				set_fsync_mark(page, 1);
> -				if (IS_INODE(page))
> -					set_dentry_mark(page, mark);
> +				if (IS_INODE(page)) {
> +					if (!is_checkpointed_node(sbi, ino) &&
> +						!has_fsynced_inode(sbi, ino))
> +						set_dentry_mark(page, 1);
> +					else
> +						set_dentry_mark(page, 0);
> +				}
>  				nwritten++;
>  			} else {
>  				set_fsync_mark(page, 0);
> @@ -1912,6 +1925,7 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
>  				write_unlock(&nm_i->nat_tree_lock);
>  			} else {
>  				write_lock(&nm_i->nat_tree_lock);
> +				nat_reset_flag(ne);
>  				__clear_nat_cache_dirty(nm_i, ne);
>  				write_unlock(&nm_i->nat_tree_lock);
>  			}
> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
> index 3043778..b8ba63c 100644
> --- a/fs/f2fs/node.h
> +++ b/fs/f2fs/node.h
> @@ -41,7 +41,8 @@ struct node_info {
> 
>  enum {
>  	IS_CHECKPOINTED,	/* is it checkpointed before? */
> -	HAS_FSYNC_MARK,		/* has the latest node fsync mark? */
> +	HAS_FSYNCED_INODE,	/* is the inode fsynced before? */
> +	HAS_LAST_FSYNC,		/* has the latest node fsync mark? */
>  };
> 
>  struct nat_entry {
> @@ -60,15 +61,9 @@ struct nat_entry {
>  #define nat_set_version(nat, v)		(nat->ni.version = v)
> 
>  #define __set_nat_cache_dirty(nm_i, ne)					\
> -	do {								\
> -		set_nat_flag(ne, IS_CHECKPOINTED, false);		\
> -		list_move_tail(&ne->list, &nm_i->dirty_nat_entries);	\
> -	} while (0)
> +		list_move_tail(&ne->list, &nm_i->dirty_nat_entries);
>  #define __clear_nat_cache_dirty(nm_i, ne)				\
> -	do {								\
> -		set_nat_flag(ne, IS_CHECKPOINTED, true);		\
> -		list_move_tail(&ne->list, &nm_i->nat_entries);		\
> -	} while (0)
> +		list_move_tail(&ne->list, &nm_i->nat_entries);
>  #define inc_node_version(version)	(++version)
> 
>  static inline void set_nat_flag(struct nat_entry *ne,
> @@ -87,6 +82,14 @@ static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
>  	return ne->flag & mask;
>  }
> 
> +static inline void nat_reset_flag(struct nat_entry *ne)
> +{
> +	/* these states can be set only after checkpoint was done */
> +	set_nat_flag(ne, IS_CHECKPOINTED, true);
> +	set_nat_flag(ne, HAS_FSYNCED_INODE, false);
> +	set_nat_flag(ne, HAS_LAST_FSYNC, true);
> +}
> +
>  static inline void node_info_from_raw_nat(struct node_info *ni,
>  						struct f2fs_nat_entry *raw_ne)
>  {
> --
> 1.8.5.2 (Apple Git-48)
> 
> 
> ------------------------------------------------------------------------------
> Want excitement?
> Manually upgrade your production database.
> When you want reliability, choose Perforce
> Perforce version control. Predictably reliable.
> http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


------------------------------------------------------------------------------
Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer
Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports
Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper
Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer
http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk