replace d_add_unique() with saner primitive
new primitive: d_exact_alias(dentry, inode). If there is an unhashed
dentry with the same name/parent and given inode, rehash, grab and
return it. Otherwise, return NULL. The only caller of d_add_unique()
switched to d_exact_alias() + d_splice_alias().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/dcache.c b/fs/dcache.c
index 2398f9f9..4d20bf5 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1782,81 +1782,6 @@
EXPORT_SYMBOL(d_instantiate);
/**
- * d_instantiate_unique - instantiate a non-aliased dentry
- * @entry: dentry to instantiate
- * @inode: inode to attach to this dentry
- *
- * Fill in inode information in the entry. On success, it returns NULL.
- * If an unhashed alias of "entry" already exists, then we return the
- * aliased dentry instead and drop one reference to inode.
- *
- * Note that in order to avoid conflicts with rename() etc, the caller
- * had better be holding the parent directory semaphore.
- *
- * This also assumes that the inode count has been incremented
- * (or otherwise set) by the caller to indicate that it is now
- * in use by the dcache.
- */
-static struct dentry *__d_instantiate_unique(struct dentry *entry,
- struct inode *inode)
-{
- struct dentry *alias;
- int len = entry->d_name.len;
- const char *name = entry->d_name.name;
- unsigned int hash = entry->d_name.hash;
-
- if (!inode) {
- __d_instantiate(entry, NULL);
- return NULL;
- }
-
- hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
- /*
- * Don't need alias->d_lock here, because aliases with
- * d_parent == entry->d_parent are not subject to name or
- * parent changes, because the parent inode i_mutex is held.
- */
- if (alias->d_name.hash != hash)
- continue;
- if (alias->d_parent != entry->d_parent)
- continue;
- if (alias->d_name.len != len)
- continue;
- if (dentry_cmp(alias, name, len))
- continue;
- __dget(alias);
- return alias;
- }
-
- __d_instantiate(entry, inode);
- return NULL;
-}
-
-struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
-{
- struct dentry *result;
-
- BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
-
- if (inode)
- spin_lock(&inode->i_lock);
- result = __d_instantiate_unique(entry, inode);
- if (inode)
- spin_unlock(&inode->i_lock);
-
- if (!result) {
- security_d_instantiate(entry, inode);
- return NULL;
- }
-
- BUG_ON(!d_unhashed(result));
- iput(inode);
- return result;
-}
-
-EXPORT_SYMBOL(d_instantiate_unique);
-
-/**
* d_instantiate_no_diralias - instantiate a non-aliased dentry
* @entry: dentry to complete
* @inode: inode to attach to this dentry
@@ -2437,6 +2362,56 @@
EXPORT_SYMBOL(d_rehash);
/**
+ * d_exact_alias - find and hash an exact unhashed alias
+ * @entry: dentry to add
+ * @inode: The inode to go with this dentry
+ *
+ * If an unhashed dentry with the same name/parent and desired
+ * inode already exists, hash and return it. Otherwise, return
+ * NULL.
+ *
+ * Parent directory should be locked.
+ */
+struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
+{
+ struct dentry *alias;
+ int len = entry->d_name.len;
+ const char *name = entry->d_name.name;
+ unsigned int hash = entry->d_name.hash;
+
+ spin_lock(&inode->i_lock);
+ hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
+ /*
+ * Don't need alias->d_lock here, because aliases with
+ * d_parent == entry->d_parent are not subject to name or
+ * parent changes, because the parent inode i_mutex is held.
+ */
+ if (alias->d_name.hash != hash)
+ continue;
+ if (alias->d_parent != entry->d_parent)
+ continue;
+ if (alias->d_name.len != len)
+ continue;
+ if (dentry_cmp(alias, name, len))
+ continue;
+ spin_lock(&alias->d_lock);
+ if (!d_unhashed(alias)) {
+ spin_unlock(&alias->d_lock);
+ alias = NULL;
+ } else {
+ __dget_dlock(alias);
+ _d_rehash(alias);
+ spin_unlock(&alias->d_lock);
+ }
+ spin_unlock(&inode->i_lock);
+ return alias;
+ }
+ spin_unlock(&inode->i_lock);
+ return NULL;
+}
+EXPORT_SYMBOL(d_exact_alias);
+
+/**
* dentry_update_name_case - update case insensitive dentry with a new name
* @dentry: dentry to be updated
* @name: new name