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Commit 31dec132 authored by Al Viro's avatar Al Viro
Browse files

fold try_to_ascend() into the sole remaining caller 



There used to be a bunch of tree-walkers in dcache.c, all alike.
try_to_ascend() had been introduced to abstract a piece of logics
duplicated in all of them.  These days all these tree-walkers are
implemented via the same iterator (d_walk()), which is the only
remaining caller of try_to_ascend(), so let's fold it back...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 482db906

fs/dcache.c

+18 −31
Original line number Diff line number Diff line
@@ -438,7 +438,7 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) 
{

	list_del(&dentry->d_u.d_child);

	/*

	 * Inform try_to_ascend() that we are no longer attached to the

	 * Inform d_walk() that we are no longer attached to the

	 * dentry tree

	 */

	dentry->d_flags |= DCACHE_DENTRY_KILLED;
@@ -1038,34 +1038,6 @@ void shrink_dcache_sb(struct super_block *sb) 
}

EXPORT_SYMBOL(shrink_dcache_sb);



/*

 * This tries to ascend one level of parenthood, but

 * we can race with renaming, so we need to re-check

 * the parenthood after dropping the lock and check

 * that the sequence number still matches.

 */

static struct dentry *try_to_ascend(struct dentry *old, unsigned seq)

{

	struct dentry *new = old->d_parent;



	rcu_read_lock();

	spin_unlock(&old->d_lock);

	spin_lock(&new->d_lock);



	/*

	 * might go back up the wrong parent if we have had a rename

	 * or deletion

	 */

	if (new != old->d_parent ||

		 (old->d_flags & DCACHE_DENTRY_KILLED) ||

		 need_seqretry(&rename_lock, seq)) {

		spin_unlock(&new->d_lock);

		new = NULL;

	}

	rcu_read_unlock();

	return new;

}



/**

 * enum d_walk_ret - action to talke during tree walk

 * @D_WALK_CONTINUE:	contrinue walk
@@ -1154,9 +1126,24 @@ static void d_walk(struct dentry *parent, void *data, 
	 */

	if (this_parent != parent) {

		struct dentry *child = this_parent;

		this_parent = try_to_ascend(this_parent, seq);

		if (!this_parent)

		this_parent = child->d_parent;



		rcu_read_lock();

		spin_unlock(&child->d_lock);

		spin_lock(&this_parent->d_lock);



		/*

		 * might go back up the wrong parent if we have had a rename

		 * or deletion

		 */

		if (this_parent != child->d_parent ||

			 (child->d_flags & DCACHE_DENTRY_KILLED) ||

			 need_seqretry(&rename_lock, seq)) {

			spin_unlock(&this_parent->d_lock);

			rcu_read_unlock();

			goto rename_retry;

		}

		rcu_read_unlock();

		next = child->d_u.d_child.next;

		goto resume;

	}