On Wed, 16 Mar 2011 18:48:50 +0900, Itaru Kitayama wrote:
> Hi Miao,
> 
> The V4 still hangs. Does the new function, btrfs_update_inode_nodelayed() you 
> introduced to the V4
> need take care of a delayed node (commit delayed items of the inode and set 
> the delayed note to NULL)?

I think there no delayed item because we commit all the delayed items when we 
start committing
transaction.

> 
> Below is my experimental patch on top of V4 trying to avoid taking 
> trans_mutex in btrfs_remove_delayed_node(), 
> but still hangs. Could you take a look at it? Thanks.

It is so strange I can not reproduce it on my machine. But by reviewing the 
code, I think some inodes
may be updated when committing the transaction, it makes the filesystem hang.

> 
> Itaru
> 
> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
> index 495a6af..b6ea082 100644
> --- a/fs/btrfs/delayed-inode.c
> +++ b/fs/btrfs/delayed-inode.c
> @@ -1006,9 +1006,9 @@ int btrfs_run_delayed_items(struct btrfs_trans_handle 
> *trans,
>       return ret;
>  }
>  
> -int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
> -                                  struct btrfs_root *root,
> -                                  struct inode *inode)
> +int __btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
> +                                    struct btrfs_root *root,
> +                                    struct inode *inode, int delayed_update)
>  {
>       struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
>       struct btrfs_path *path;
> @@ -1036,7 +1036,7 @@ int btrfs_commit_inode_delayed_items(struct 
> btrfs_trans_handle *trans,
>       if (!ret)
>               ret = btrfs_delete_delayed_items(trans, path, root,
>                                                delayed_node);
> -     if (!ret)
> +     if (!ret && delayed_update)
>               ret = btrfs_update_delayed_inode(trans, root, path,
>                                                delayed_node);
>       btrfs_free_path(path);
> @@ -1044,13 +1044,27 @@ int btrfs_commit_inode_delayed_items(struct 
> btrfs_trans_handle *trans,
>       return ret;
>  }
>  
> +int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
> +                                  struct btrfs_root *root,
> +                                  struct inode *inode)
> +{
> +     return __btrfs_commit_inode_delayed_items(trans, root, inode, 1);
> +}
> +
> +int btrfs_commit_inode_delayed_items_no_delayed_update(struct 
> btrfs_trans_handle *trans,
> +                                                    struct btrfs_root *root,
> +                                                    struct inode *inode)
> +{
> +     return __btrfs_commit_inode_delayed_items(trans, root, inode, 0);
> +}
> +
>  int btrfs_remove_delayed_node(struct inode *inode)
>  {
>       struct btrfs_trans_handle *trans;
>       struct btrfs_root *root = BTRFS_I(inode)->root;
>       struct btrfs_delayed_node *delayed_node = BTRFS_I(inode)->delayed_node;
>       int ret;
> -
> +     
>       if (!delayed_node)
>               return 0;
>  
> diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h
> index d4134bc..b6986df 100644
> --- a/fs/btrfs/delayed-inode.h
> +++ b/fs/btrfs/delayed-inode.h
> @@ -114,6 +114,11 @@ void btrfs_balance_delayed_items(struct btrfs_root 
> *root);
>  int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
>                                    struct btrfs_root *root,
>                                    struct inode *inode);
> +int btrfs_commit_inode_delayed_items_no_delayed_update(
> +                             struct btrfs_trans_handle *trans,
> +                             struct btrfs_root *root,
> +                             struct inode *inode);
> +
>  /* Used for evicting the inode. */
>  int btrfs_remove_delayed_node(struct inode *inode);
>  int btrfs_kill_delayed_inode_items(struct btrfs_trans_handle *trans,
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 5299d9c..e198051 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -2611,8 +2611,12 @@ noinline int btrfs_update_inode_nodelayed(struct 
> btrfs_trans_handle *trans,
>       struct btrfs_inode_item *inode_item;
>       struct btrfs_path *path;
>       struct extent_buffer *leaf;
> +     struct btrfs_delayed_node *delayed_node;
>       int ret;
>  
> +     btrfs_commit_inode_delayed_items_no_delayed_update(trans, root, inode);
> +     delayed_node = NULL;
> +
>       path = btrfs_alloc_path();
>       if (!path)
>               return -ENOMEM;
> 

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