static void __d_free(struct dentry *dentry)
{
+ WARN_ON(!list_empty(&dentry->d_alias));
if (dname_external(dentry))
kfree(dentry->d_name.name);
kmem_cache_free(dentry_cache, dentry);
dentry_stat.nr_dentry--; /* For d_free, below */
/*drops the locks, at that point nobody can reach this dentry */
dentry_iput(dentry);
- parent = dentry->d_parent;
+ if (IS_ROOT(dentry))
+ parent = NULL;
+ else
+ parent = dentry->d_parent;
d_free(dentry);
- return dentry == parent ? NULL : parent;
+ return parent;
}
/*
BUG();
}
- parent = dentry->d_parent;
- if (parent == dentry)
+ if (IS_ROOT(dentry))
parent = NULL;
- else
+ else {
+ parent = dentry->d_parent;
atomic_dec(&parent->d_count);
+ }
list_del(&dentry->d_u.d_child);
detached++;
return d_alloc(parent, &q);
}
+/* the caller must hold dcache_lock */
+static void __d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (inode)
+ list_add(&dentry->d_alias, &inode->i_dentry);
+ dentry->d_inode = inode;
+ fsnotify_d_instantiate(dentry, inode);
+}
+
/**
* d_instantiate - fill in inode information for a dentry
* @entry: dentry to complete
{
BUG_ON(!list_empty(&entry->d_alias));
spin_lock(&dcache_lock);
- if (inode)
- list_add(&entry->d_alias, &inode->i_dentry);
- entry->d_inode = inode;
- fsnotify_d_instantiate(entry, inode);
+ __d_instantiate(entry, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(entry, inode);
}
unsigned int hash = entry->d_name.hash;
if (!inode) {
- entry->d_inode = NULL;
+ __d_instantiate(entry, NULL);
return NULL;
}
return alias;
}
- list_add(&entry->d_alias, &inode->i_dentry);
- entry->d_inode = inode;
- fsnotify_d_instantiate(entry, inode);
+ __d_instantiate(entry, inode);
return NULL;
}
return dentry_hashtable + (hash & D_HASHMASK);
}
-/**
- * d_alloc_anon - allocate an anonymous dentry
- * @inode: inode to allocate the dentry for
- *
- * This is similar to d_alloc_root. It is used by filesystems when
- * creating a dentry for a given inode, often in the process of
- * mapping a filehandle to a dentry. The returned dentry may be
- * anonymous, or may have a full name (if the inode was already
- * in the cache). The file system may need to make further
- * efforts to connect this dentry into the dcache properly.
- *
- * When called on a directory inode, we must ensure that
- * the inode only ever has one dentry. If a dentry is
- * found, that is returned instead of allocating a new one.
- *
- * On successful return, the reference to the inode has been transferred
- * to the dentry. If %NULL is returned (indicating kmalloc failure),
- * the reference on the inode has not been released.
- */
-
-struct dentry * d_alloc_anon(struct inode *inode)
-{
- static const struct qstr anonstring = { .name = "" };
- struct dentry *tmp;
- struct dentry *res;
-
- if ((res = d_find_alias(inode))) {
- iput(inode);
- return res;
- }
-
- tmp = d_alloc(NULL, &anonstring);
- if (!tmp)
- return NULL;
-
- tmp->d_parent = tmp; /* make sure dput doesn't croak */
-
- 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)
- iput(inode);
- if (tmp)
- dput(tmp);
- return res;
-}
-
/**
* d_obtain_alias - find or allocate a dentry for a given inode
* @inode: inode to allocate the dentry for
* allocating a new one.
*
* On successful return, the reference to the inode has been transferred
- * to the dentry. If %NULL is returned (indicating kmalloc failure),
- * the reference on the inode has been released. To make it easier
- * to use in export operations a NULL or IS_ERR inode may be passed in
- * and will be casted to the corresponding NULL or IS_ERR dentry.
+ * to the dentry. In case of an error the reference on the inode is released.
+ * To make it easier to use in export operations a %NULL or IS_ERR inode may
+ * be passed in and will be the error will be propagate to the return value,
+ * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
*/
struct dentry *d_obtain_alias(struct inode *inode)
{
- struct dentry *dentry;
+ static const struct qstr anonstring = { .name = "" };
+ struct dentry *tmp;
+ struct dentry *res;
if (!inode)
- return NULL;
+ return ERR_PTR(-ESTALE);
if (IS_ERR(inode))
return ERR_CAST(inode);
- dentry = d_alloc_anon(inode);
- if (!dentry) {
- iput(inode);
- dentry = ERR_PTR(-ENOMEM);
+ res = d_find_alias(inode);
+ if (res)
+ goto out_iput;
+
+ tmp = d_alloc(NULL, &anonstring);
+ if (!tmp) {
+ res = ERR_PTR(-ENOMEM);
+ goto out_iput;
}
- return dentry;
+ tmp->d_parent = tmp; /* make sure dput doesn't croak */
+
+ spin_lock(&dcache_lock);
+ res = __d_find_alias(inode, 0);
+ if (res) {
+ spin_unlock(&dcache_lock);
+ dput(tmp);
+ goto out_iput;
+ }
+
+ /* attach a disconnected dentry */
+ spin_lock(&tmp->d_lock);
+ tmp->d_sb = inode->i_sb;
+ 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;
+
+ out_iput:
+ iput(inode);
+ return res;
}
EXPORT_SYMBOL_GPL(d_obtain_alias);
new = __d_find_alias(inode, 1);
if (new) {
BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
- fsnotify_d_instantiate(new, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(new, inode);
d_rehash(dentry);
d_move(new, dentry);
iput(inode);
} else {
- /* d_instantiate takes dcache_lock, so we do it by hand */
- list_add(&dentry->d_alias, &inode->i_dentry);
- dentry->d_inode = inode;
- fsnotify_d_instantiate(dentry, inode);
+ /* already taking dcache_lock, so d_add() by hand */
+ __d_instantiate(dentry, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(dentry, inode);
d_rehash(dentry);
* d_instantiate() by hand because it takes dcache_lock which
* we already hold.
*/
- list_add(&found->d_alias, &inode->i_dentry);
- found->d_inode = inode;
+ __d_instantiate(found, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(found, inode);
return found;
* d_validate - verify dentry provided from insecure source
* @dentry: The dentry alleged to be valid child of @dparent
* @dparent: The parent dentry (known to be valid)
- * @hash: Hash of the dentry
- * @len: Length of the name
*
* An insecure source has sent us a dentry, here we verify it and dget() it.
* This is used by ncpfs in its readdir implementation.
spin_unlock(&dcache_lock);
}
-/*
- * Helper that returns 1 if p1 is a parent of p2, else 0
+/**
+ * d_ancestor - search for an ancestor
+ * @p1: ancestor dentry
+ * @p2: child dentry
+ *
+ * Returns the ancestor dentry of p2 which is a child of p1, if p1 is
+ * an ancestor of p2, else NULL.
*/
-static int d_isparent(struct dentry *p1, struct dentry *p2)
+struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
{
struct dentry *p;
- for (p = p2; p->d_parent != p; p = p->d_parent) {
+ for (p = p2; !IS_ROOT(p); p = p->d_parent) {
if (p->d_parent == p1)
- return 1;
+ return p;
}
- return 0;
+ return NULL;
}
/*
/* Check for loops */
ret = ERR_PTR(-ELOOP);
- if (d_isparent(alias, dentry))
+ if (d_ancestor(alias, dentry))
goto out_err;
/* See lock_rename() */
if (!inode) {
actual = dentry;
- dentry->d_inode = NULL;
+ __d_instantiate(dentry, NULL);
goto found_lock;
}
* Caller must ensure that "new_dentry" is pinned before calling is_subdir()
*/
-int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry)
+int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
{
int result;
- struct dentry * saved = new_dentry;
unsigned long seq;
- /* need rcu_readlock to protect against the d_parent trashing due to
- * d_move
+ /* FIXME: This is old behavior, needed? Please check callers. */
+ if (new_dentry == old_dentry)
+ return 1;
+
+ /*
+ * Need rcu_readlock to protect against the d_parent trashing
+ * due to d_move
*/
rcu_read_lock();
- do {
+ do {
/* for restarting inner loop in case of seq retry */
- new_dentry = saved;
- result = 0;
seq = read_seqbegin(&rename_lock);
- for (;;) {
- if (new_dentry != old_dentry) {
- struct dentry * parent = new_dentry->d_parent;
- if (parent == new_dentry)
- break;
- new_dentry = parent;
- continue;
- }
+ if (d_ancestor(old_dentry, new_dentry))
result = 1;
- break;
- }
+ else
+ result = 0;
} while (read_seqretry(&rename_lock, seq));
rcu_read_unlock();
}
EXPORT_SYMBOL(d_alloc);
-EXPORT_SYMBOL(d_alloc_anon);
EXPORT_SYMBOL(d_alloc_root);
EXPORT_SYMBOL(d_delete);
EXPORT_SYMBOL(d_find_alias);
projects / linux-2.6-omap-h63xx.git / blobdiff