[Ocfs2-devel] [PATCH 4/4] ocfs2: limit the number of inodes in orphanscan

[Joel Becker]

On Fri, Jul 29, 2011 at 06:06:23PM +0800, Wengang Wang wrote:
> During orphanscan, limit the scan number in a single loop to avoid OOM.

How does this OOM?  Please explain this in the patch and in the patch
description.  Or, conversely, free the resources the orphan scan is done
using.

Joel

> 
> Signed-off-by: Wengang Wang <wen.gang.wang at oracle.com>
> ---
>  fs/ocfs2/journal.c |    9 +++++++++
>  1 files changed, 9 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
> index 7d4e1ca..1c0487b 100644
> --- a/fs/ocfs2/journal.c
> +++ b/fs/ocfs2/journal.c
> @@ -56,6 +56,7 @@
>  DEFINE_SPINLOCK(trans_inc_lock);
>  
>  #define ORPHAN_SCAN_SCHEDULE_TIMEOUT 300000
> +#define ORPHAN_SCAN_ITEMS_PER_LOOP 1000
>  
>  static int ocfs2_force_read_journal(struct inode *inode);
>  static int ocfs2_recover_node(struct ocfs2_super *osb,
> @@ -1926,6 +1927,7 @@ struct ocfs2_orphan_filldir_priv {
>  	struct inode		*head;
>  	struct ocfs2_super	*osb;
>  	struct 			inode *orphan_dir;
> +	int			count;
>  };
>  
>  static int ocfs2_orphan_filldir(void *priv, const char *name, int name_len,
> @@ -1964,6 +1966,12 @@ static int ocfs2_orphan_filldir(void *priv, const char *name, int name_len,
>  	}
>  	spin_unlock(&o_orphandir->ip_lock);
>  
> +	/*
> +	 * reading limited number of inodes in a single loop to avoid OOM
> +	 */
> +	if ( ++p->count == ORPHAN_SCAN_ITEMS_PER_LOOP )
> +		return -EAGAIN;
> +
>  	return 0;
>  }
>  
> @@ -1978,6 +1986,7 @@ static int ocfs2_queue_orphans(struct ocfs2_super *osb,
>  
>  	priv.osb = osb;
>  	priv.head = *head;
> +	priv.count = 0;
>  
>  	orphan_dir_inode = ocfs2_get_system_file_inode(osb,
>  						       ORPHAN_DIR_SYSTEM_INODE,
> -- 
> 1.7.5.2
> 
> 
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