1 files changed, 26 insertions, 98 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 3a463d0c4fe..fbfae008ba4 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -455,24 +455,6 @@ void d_drop(struct dentry *dentry)
 EXPORT_SYMBOL(d_drop);
 
 /*
- * d_clear_need_lookup - drop a dentry from cache and clear the need lookup flag
- * @dentry: dentry to drop
- *
- * This is called when we do a lookup on a placeholder dentry that needed to be
- * looked up.  The dentry should have been hashed in order for it to be found by
- * the lookup code, but now needs to be unhashed while we do the actual lookup
- * and clear the DCACHE_NEED_LOOKUP flag.
- */
-void d_clear_need_lookup(struct dentry *dentry)
-{
-	spin_lock(&dentry->d_lock);
-	__d_drop(dentry);
-	dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
-	spin_unlock(&dentry->d_lock);
-}
-EXPORT_SYMBOL(d_clear_need_lookup);
-
-/*
  * Finish off a dentry we've decided to kill.
  * dentry->d_lock must be held, returns with it unlocked.
  * If ref is non-zero, then decrement the refcount too.
@@ -565,13 +547,7 @@ repeat:
  	if (d_unhashed(dentry))
 		goto kill_it;
 
-	/*
-	 * If this dentry needs lookup, don't set the referenced flag so that it
-	 * is more likely to be cleaned up by the dcache shrinker in case of
-	 * memory pressure.
-	 */
-	if (!d_need_lookup(dentry))
-		dentry->d_flags |= DCACHE_REFERENCED;
+	dentry->d_flags |= DCACHE_REFERENCED;
 	dentry_lru_add(dentry);
 
 	dentry->d_count--;
@@ -699,11 +675,10 @@ EXPORT_SYMBOL(dget_parent);
 static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
 {
 	struct dentry *alias, *discon_alias;
-	struct hlist_node *p;
 
 again:
 	discon_alias = NULL;
-	hlist_for_each_entry(alias, p, &inode->i_dentry, d_alias) {
+	hlist_for_each_entry(alias, &inode->i_dentry, d_alias) {
 		spin_lock(&alias->d_lock);
  		if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
 			if (IS_ROOT(alias) &&
@@ -754,10 +729,9 @@ EXPORT_SYMBOL(d_find_alias);
 void d_prune_aliases(struct inode *inode)
 {
 	struct dentry *dentry;
-	struct hlist_node *p;
 restart:
 	spin_lock(&inode->i_lock);
-	hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) {
+	hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
 		spin_lock(&dentry->d_lock);
 		if (!dentry->d_count) {
 			__dget_dlock(dentry);
@@ -1382,6 +1356,7 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
 	WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH	|
 				DCACHE_OP_COMPARE	|
 				DCACHE_OP_REVALIDATE	|
+				DCACHE_OP_WEAK_REVALIDATE	|
 				DCACHE_OP_DELETE ));
 	dentry->d_op = op;
 	if (!op)
@@ -1392,6 +1367,8 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
 		dentry->d_flags |= DCACHE_OP_COMPARE;
 	if (op->d_revalidate)
 		dentry->d_flags |= DCACHE_OP_REVALIDATE;
+	if (op->d_weak_revalidate)
+		dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE;
 	if (op->d_delete)
 		dentry->d_flags |= DCACHE_OP_DELETE;
 	if (op->d_prune)
@@ -1464,14 +1441,13 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
 	int len = entry->d_name.len;
 	const char *name = entry->d_name.name;
 	unsigned int hash = entry->d_name.hash;
-	struct hlist_node *p;
 
 	if (!inode) {
 		__d_instantiate(entry, NULL);
 		return NULL;
 	}
 
-	hlist_for_each_entry(alias, p, &inode->i_dentry, d_alias) {
+	hlist_for_each_entry(alias, &inode->i_dentry, d_alias) {
 		/*
 		 * Don't need alias->d_lock here, because aliases with
 		 * d_parent == entry->d_parent are not subject to name or
@@ -1583,7 +1559,7 @@ EXPORT_SYMBOL(d_find_any_alias);
  */
 struct dentry *d_obtain_alias(struct inode *inode)
 {
-	static const struct qstr anonstring = { .name = "" };
+	static const struct qstr anonstring = QSTR_INIT("/", 1);
 	struct dentry *tmp;
 	struct dentry *res;
 
@@ -1696,7 +1672,6 @@ EXPORT_SYMBOL(d_splice_alias);
 struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 			struct qstr *name)
 {
-	int error;
 	struct dentry *found;
 	struct dentry *new;
 
@@ -1705,10 +1680,12 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 	 * if not go ahead and create it now.
 	 */
 	found = d_hash_and_lookup(dentry->d_parent, name);
+	if (unlikely(IS_ERR(found)))
+		goto err_out;
 	if (!found) {
 		new = d_alloc(dentry->d_parent, name);
 		if (!new) {
-			error = -ENOMEM;
+			found = ERR_PTR(-ENOMEM);
 			goto err_out;
 		}
 
@@ -1737,13 +1714,6 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 	}
 
 	/*
-	 * We are going to instantiate this dentry, unhash it and clear the
-	 * lookup flag so we can do that.
-	 */
-	if (unlikely(d_need_lookup(found)))
-		d_clear_need_lookup(found);
-
-	/*
 	 * Negative dentry: instantiate it unless the inode is a directory and
 	 * already has a dentry.
 	 */
@@ -1756,7 +1726,7 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 
 err_out:
 	iput(inode);
-	return ERR_PTR(error);
+	return found;
 }
 EXPORT_SYMBOL(d_add_ci);
 
@@ -1920,7 +1890,7 @@ seqretry:
  * dentry is returned. The caller must use dput to free the entry when it has
  * finished using it. %NULL is returned if the dentry does not exist.
  */
-struct dentry *d_lookup(struct dentry *parent, struct qstr *name)
+struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name)
 {
 	struct dentry *dentry;
 	unsigned seq;
@@ -1950,7 +1920,7 @@ EXPORT_SYMBOL(d_lookup);
  *
  * __d_lookup callers must be commented.
  */
-struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
+struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
 {
 	unsigned int len = name->len;
 	unsigned int hash = name->hash;
@@ -2028,12 +1998,10 @@ next:
  * @dir: Directory to search in
  * @name: qstr of name we wish to find
  *
- * On hash failure or on lookup failure NULL is returned.
+ * On lookup failure NULL is returned; on bad name - ERR_PTR(-error)
  */
 struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
 {
-	struct dentry *dentry = NULL;
-
 	/*
 	 * Check for a fs-specific hash function. Note that we must
 	 * calculate the standard hash first, as the d_op->d_hash()
@@ -2041,13 +2009,13 @@ struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
 	 */
 	name->hash = full_name_hash(name->name, name->len);
 	if (dir->d_flags & DCACHE_OP_HASH) {
-		if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0)
-			goto out;
+		int err = dir->d_op->d_hash(dir, dir->d_inode, name);
+		if (unlikely(err < 0))
+			return ERR_PTR(err);
 	}
-	dentry = d_lookup(dir, name);
-out:
-	return dentry;
+	return d_lookup(dir, name);
 }
+EXPORT_SYMBOL(d_hash_and_lookup);
 
 /**
  * d_validate - verify dentry provided from insecure source (deprecated)
@@ -2425,7 +2393,7 @@ out_err:
  */
 static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
 {
-	struct dentry *dparent, *aparent;
+	struct dentry *dparent;
 
 	dentry_lock_for_move(anon, dentry);
 
@@ -2433,24 +2401,15 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
 	write_seqcount_begin(&anon->d_seq);
 
 	dparent = dentry->d_parent;
-	aparent = anon->d_parent;
 
 	switch_names(dentry, anon);
 	swap(dentry->d_name.hash, anon->d_name.hash);
 
-	dentry->d_parent = (aparent == anon) ? dentry : aparent;
-	list_del(&dentry->d_u.d_child);
-	if (!IS_ROOT(dentry))
-		list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
-	else
-		INIT_LIST_HEAD(&dentry->d_u.d_child);
-
-	anon->d_parent = (dparent == dentry) ? anon : dparent;
+	dentry->d_parent = dentry;
+	list_del_init(&dentry->d_u.d_child);
+	anon->d_parent = dparent;
 	list_del(&anon->d_u.d_child);
-	if (!IS_ROOT(anon))
-		list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs);
-	else
-		INIT_LIST_HEAD(&anon->d_u.d_child);
+	list_add(&anon->d_u.d_child, &dparent->d_subdirs);
 
 	write_seqcount_end(&dentry->d_seq);
 	write_seqcount_end(&anon->d_seq);
@@ -2753,37 +2712,6 @@ char *d_path(const struct path *path, char *buf, int buflen)
 }
 EXPORT_SYMBOL(d_path);
 
-/**
- * d_path_with_unreachable - return the path of a dentry
- * @path: path to report
- * @buf: buffer to return value in
- * @buflen: buffer length
- *
- * The difference from d_path() is that this prepends "(unreachable)"
- * to paths which are unreachable from the current process' root.
- */
-char *d_path_with_unreachable(const struct path *path, char *buf, int buflen)
-{
-	char *res = buf + buflen;
-	struct path root;
-	int error;
-
-	if (path->dentry->d_op && path->dentry->d_op->d_dname)
-		return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
-
-	get_fs_root(current->fs, &root);
-	write_seqlock(&rename_lock);
-	error = path_with_deleted(path, &root, &res, &buflen);
-	if (error > 0)
-		error = prepend_unreachable(&res, &buflen);
-	write_sequnlock(&rename_lock);
-	path_put(&root);
-	if (error)
-		res =  ERR_PTR(error);
-
-	return res;
-}
-
 /*
  * Helper function for dentry_operations.d_dname() members
  */
@@ -3066,7 +2994,7 @@ ino_t find_inode_number(struct dentry *dir, struct qstr *name)
 	ino_t ino = 0;
 
 	dentry = d_hash_and_lookup(dir, name);
-	if (dentry) {
+	if (!IS_ERR_OR_NULL(dentry)) {
 		if (dentry->d_inode)
 			ino = dentry->d_inode->i_ino;
 		dput(dentry);