[PATCH] vfs: use the predefined d_unhashed inline function instead

[PATCH] vfs: use the predefined d_unhashed inline function instead

[Denis Cheng]

Signed-off-by: Denis Cheng <crquan@gmail.com>
---
 fs/dcache.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 678d39d..62e1800 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1546,7 +1546,7 @@ static void d_move_locked(struct dentry * dentry, struct dentry * target)
 	}
 
 	/* Move the dentry to the target hash queue, if on different bucket */
-	if (dentry->d_flags & DCACHE_UNHASHED)
+	if (d_unhashed(dentry))
 		goto already_unhashed;
 
 	hlist_del_rcu(&dentry->d_hash);
-- 
1.5.3

[PATCH] fs/dcache.c: revamped to use a more straightforward and efficient way to operate

[Denis Cheng]

Signed-off-by: Denis Cheng <crquan@gmail.com>
---
 fs/dcache.c |   39 ++++++++++++++++++---------------------
 1 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 678d39d..05ed44a 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1138,29 +1138,26 @@ struct dentry * d_alloc_anon(struct inode *inode)
 	
 	spin_lock(&dcache_lock);
 	res = __d_find_alias(inode, 0);
-	if (!res) {
-		/* attach a disconnected dentry */
-		res = tmp;
-		tmp = NULL;
-		spin_lock(&res->d_lock);
-		res->d_sb = inode->i_sb;
-		res->d_parent = res;
-		res->d_inode = inode;
-		res->d_flags |= DCACHE_DISCONNECTED;
-		res->d_flags &= ~DCACHE_UNHASHED;
-		list_add(&res->d_alias, &inode->i_dentry);
-		hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
-		spin_unlock(&res->d_lock);
-
-		inode = NULL; /* don't drop reference */
-	}
-	spin_unlock(&dcache_lock);
-
-	if (inode)
+	if (unlikely(res)) {
+		spin_unlock(&dcache_lock);
 		iput(inode);
-	if (tmp)
 		dput(tmp);
-	return res;
+		return res;
+	} else {
+		/* attach a disconnected dentry */
+		spin_lock(&tmp->d_lock);
+		tmp->d_sb = inode->i_sb;
+		tmp->d_parent = tmp;
+		tmp->d_inode = inode;
+		tmp->d_flags |= DCACHE_DISCONNECTED;
+		tmp->d_flags &= ~DCACHE_UNHASHED;
+		list_add(&tmp->d_alias, &inode->i_dentry);
+		hlist_add_head(&tmp->d_hash, &inode->i_sb->s_anon);
+		spin_unlock(&tmp->d_lock);
+
+		spin_unlock(&dcache_lock);
+		return tmp;
+	}
 }
 
 
-- 
1.5.3.2

Re: [PATCH] fs/dcache.c: revamped to use a more straightforward and efficient way to operate

[Jan Kara]

  Hello,

  thanks for the patch. I have a few comments to it:
1) the patch should have a description in it, not only an email subject
2) usually, if an 'if' branch ends with return, as is the case in your
   patch, we don't use 'else' for the other branch...

BTW: I'm not convinced your code would be faster (or slower) than the
original one but you're right it will be easier to read...

								Honza

> Signed-off-by: Denis Cheng <crquan@gmail.com>
> ---
>  fs/dcache.c |   39 ++++++++++++++++++---------------------
>  1 files changed, 18 insertions(+), 21 deletions(-)
> 
> diff --git a/fs/dcache.c b/fs/dcache.c
> index 678d39d..05ed44a 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -1138,29 +1138,26 @@ struct dentry * d_alloc_anon(struct inode *inode)
>  	
>  	spin_lock(&dcache_lock);
>  	res = __d_find_alias(inode, 0);
> -	if (!res) {
> -		/* attach a disconnected dentry */
> -		res = tmp;
> -		tmp = NULL;
> -		spin_lock(&res->d_lock);
> -		res->d_sb = inode->i_sb;
> -		res->d_parent = res;
> -		res->d_inode = inode;
> -		res->d_flags |= DCACHE_DISCONNECTED;
> -		res->d_flags &= ~DCACHE_UNHASHED;
> -		list_add(&res->d_alias, &inode->i_dentry);
> -		hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
> -		spin_unlock(&res->d_lock);
> -
> -		inode = NULL; /* don't drop reference */
> -	}
> -	spin_unlock(&dcache_lock);
> -
> -	if (inode)
> +	if (unlikely(res)) {
> +		spin_unlock(&dcache_lock);
>  		iput(inode);
> -	if (tmp)
>  		dput(tmp);
> -	return res;
> +		return res;
> +	} else {
> +		/* attach a disconnected dentry */
> +		spin_lock(&tmp->d_lock);
> +		tmp->d_sb = inode->i_sb;
> +		tmp->d_parent = tmp;
> +		tmp->d_inode = inode;
> +		tmp->d_flags |= DCACHE_DISCONNECTED;
> +		tmp->d_flags &= ~DCACHE_UNHASHED;
> +		list_add(&tmp->d_alias, &inode->i_dentry);
> +		hlist_add_head(&tmp->d_hash, &inode->i_sb->s_anon);
> +		spin_unlock(&tmp->d_lock);
> +
> +		spin_unlock(&dcache_lock);
> +		return tmp;
> +	}
>  }
>  
>  
> -- 
> 1.5.3.2
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
-- 
Jan Kara <jack@suse.cz>
SuSE CR Labs