linux-ext4 - Re: [PATCH 3/4] vfs: don't let the dirty time inodes get more than a day stale

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Date:	Tue, 25 Nov 2014 18:31:26 +0100
From:	Jan Kara <jack@...e.cz>
To:	Theodore Ts'o <tytso@....edu>
Cc:	linux-fsdevel@...r.kernel.org,
	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	xfs@....sgi.com, linux-btrfs@...r.kernel.org
Subject: Re: [PATCH 3/4] vfs: don't let the dirty time inodes get more than a
 day stale

On Fri 21-11-14 14:59:23, Ted Tso wrote:
> Guarantee that the on-disk timestamps will be no more than 24 hours
> stale.
  Hum, how about reusing i_dirtied_when for this. Using that field even
makes a good sence to me...

								Honza

> Signed-off-by: Theodore Ts'o <tytso@....edu>
> ---
>  fs/fs-writeback.c  | 1 +
>  fs/inode.c         | 7 ++++++-
>  include/linux/fs.h | 1 +
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index ce7de22..eb04277 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -1141,6 +1141,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
>  	if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
>  		trace_writeback_dirty_inode_start(inode, flags);
>  
> +		inode->i_ts_dirty_day = 0;
>  		if (sb->s_op->dirty_inode)
>  			sb->s_op->dirty_inode(inode, flags);
>  
> diff --git a/fs/inode.c b/fs/inode.c
> index 6e91aca..f0d6232 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1511,6 +1511,7 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
>   */
>  static int update_time(struct inode *inode, struct timespec *time, int flags)
>  {
> +	int days_since_boot = jiffies / (HZ * 86400);
>  	int ret;
>  
>  	if (inode->i_op->update_time) {
> @@ -1527,12 +1528,16 @@ static int update_time(struct inode *inode, struct timespec *time, int flags)
>  		if (flags & S_MTIME)
>  			inode->i_mtime = *time;
>  	}
> -	if (inode->i_sb->s_flags & MS_LAZYTIME) {
> +	if ((inode->i_sb->s_flags & MS_LAZYTIME) &&
> +	    (!inode->i_ts_dirty_day ||
> +	     inode->i_ts_dirty_day == days_since_boot)) {
>  		spin_lock(&inode->i_lock);
>  		inode->i_state |= I_DIRTY_TIME;
>  		spin_unlock(&inode->i_lock);
> +		inode->i_ts_dirty_day = days_since_boot;
>  		return 0;
>  	}
> +	inode->i_ts_dirty_day = 0;
>  	if (inode->i_op->write_time)
>  		return inode->i_op->write_time(inode);
>  	mark_inode_dirty_sync(inode);
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 489b2f2..e3574cd 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -575,6 +575,7 @@ struct inode {
>  	struct timespec		i_ctime;
>  	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
>  	unsigned short          i_bytes;
> +	unsigned short		i_ts_dirty_day;
>  	unsigned int		i_blkbits;
>  	blkcnt_t		i_blocks;
>  
> -- 
> 2.1.0
> 
> --
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-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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