expand dentry_kill(dentry, 0) in shrink_dentry_list()

Result will be massaged to saner shape in the next commits. It is ugly, no questions - the point of that one is to be a provably equivalent transformation (and it might be worth splitting a bit more). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

expand dentry_kill(dentry, 0) in shrink_dentry_list()
Result will be massaged to saner shape in the next commits. It is ugly, no questions - the point of that one is to be a provably equivalent transformation (and it might be worth splitting a bit more). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
1 parent e55fd01154
Showing 1 changed file with 17 additions and 13 deletions Side-by-side Diff
fs/dcache.c
@@ -801,6 +801,7 @@
 	struct dentry *dentry, *parent;
  
 	while (!list_empty(list)) {
+		struct inode *inode;
 		dentry = list_entry(list->prev, struct dentry, d_lru);
 		spin_lock(&dentry->d_lock);
 		/*
  
@@ -828,23 +829,26 @@
 			continue;
 		}
  
-		parent = dentry_kill(dentry, 0);
-		/*
-		 * If dentry_kill returns NULL, we have nothing more to do.
-		 */
-		if (!parent)
-			continue;
-
-		if (unlikely(parent == dentry)) {
-			/*
-			 * trylocks have failed and d_lock has been held the
-			 * whole time, so it could not have been added to any
-			 * other lists. Just add it back to the shrink list.
-			 */
+		inode = dentry->d_inode;
+		if (inode && unlikely(!spin_trylock(&inode->i_lock))) {
 			d_shrink_add(dentry, list);
 			spin_unlock(&dentry->d_lock);
 			continue;
 		}
+
+		parent = NULL;
+		if (!IS_ROOT(dentry)) {
+			parent = dentry->d_parent;
+			if (unlikely(!spin_trylock(&parent->d_lock))) {
+				if (inode)
+					spin_unlock(&inode->i_lock);
+				d_shrink_add(dentry, list);
+				spin_unlock(&dentry->d_lock);
+				continue;
+			}
+		}
+
+		__dentry_kill(dentry);
 		/*
 		 * We need to prune ancestors too. This is necessary to prevent
 		 * quadratic behavior of shrink_dcache_parent(), but is also
...	...	@@ -801,6 +801,7 @@
801	801	struct dentry dentry, parent;
802	802
803	803	while (!list_empty(list)) {
	804	+ struct inode *inode;
804	805	dentry = list_entry(list->prev, struct dentry, d_lru);
805	806	spin_lock(&dentry->d_lock);
806	807	/*
807	808
...	...	@@ -828,23 +829,26 @@
828	829	continue;
829	830	}
830	831
831		- parent = dentry_kill(dentry, 0);
832		- /*
833		- * If dentry_kill returns NULL, we have nothing more to do.
834		- */
835		- if (!parent)
836		- continue;
837		-
838		- if (unlikely(parent == dentry)) {
839		- /*
840		- * trylocks have failed and d_lock has been held the
841		- * whole time, so it could not have been added to any
842		- * other lists. Just add it back to the shrink list.
843		- */
	832	+ inode = dentry->d_inode;
	833	+ if (inode && unlikely(!spin_trylock(&inode->i_lock))) {
844	834	d_shrink_add(dentry, list);
845	835	spin_unlock(&dentry->d_lock);
846	836	continue;
847	837	}
	838	+
	839	+ parent = NULL;
	840	+ if (!IS_ROOT(dentry)) {
	841	+ parent = dentry->d_parent;
	842	+ if (unlikely(!spin_trylock(&parent->d_lock))) {
	843	+ if (inode)
	844	+ spin_unlock(&inode->i_lock);
	845	+ d_shrink_add(dentry, list);
	846	+ spin_unlock(&dentry->d_lock);
	847	+ continue;
	848	+ }
	849	+ }
	850	+
	851	+ __dentry_kill(dentry);
848	852	/*
849	853	* We need to prune ancestors too. This is necessary to prevent
850	854	* quadratic behavior of shrink_dcache_parent(), but is also