return 1;
}
-static struct dentry_operations configfs_dentry_ops = {
+static const struct dentry_operations configfs_dentry_ops = {
.d_iput = configfs_d_iput,
/* simple_delete_dentry() isn't exported */
.d_delete = configfs_d_delete,
* The only thing special about this is that we remove any files in
* the directory before we remove the directory, and we've inlined
* what used to be configfs_rmdir() below, instead of calling separately.
+ *
+ * Caller holds the mutex of the item's inode
*/
static void configfs_remove_dir(struct config_item * item)
ret = 0;
list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
- if (sd->s_type & CONFIGFS_NOT_PINNED)
+ if (!sd->s_element ||
+ (sd->s_type & CONFIGFS_NOT_PINNED))
continue;
if (sd->s_type & CONFIGFS_USET_DEFAULT) {
/* Abort if racing with mkdir() */
static int populate_groups(struct config_group *group)
{
struct config_group *new_group;
- struct dentry *dentry = group->cg_item.ci_dentry;
int ret = 0;
int i;
if (group->default_groups) {
- /*
- * FYI, we're faking mkdir here
- * I'm not sure we need this semaphore, as we're called
- * from our parent's mkdir. That holds our parent's
- * i_mutex, so afaik lookup cannot continue through our
- * parent to find us, let alone mess with our tree.
- * That said, taking our i_mutex is closer to mkdir
- * emulation, and shouldn't hurt.
- */
- mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
-
for (i = 0; group->default_groups[i]; i++) {
new_group = group->default_groups[i];
ret = create_default_group(group, new_group);
- if (ret)
+ if (ret) {
+ detach_groups(group);
break;
+ }
}
-
- mutex_unlock(&dentry->d_inode->i_mutex);
}
- if (ret)
- detach_groups(group);
-
return ret;
}
if (!ret) {
ret = populate_attrs(item);
if (ret) {
+ /*
+ * We are going to remove an inode and its dentry but
+ * the VFS may already have hit and used them. Thus,
+ * we must lock them as rmdir() would.
+ */
+ mutex_lock(&dentry->d_inode->i_mutex);
configfs_remove_dir(item);
+ dentry->d_inode->i_flags |= S_DEAD;
+ mutex_unlock(&dentry->d_inode->i_mutex);
d_delete(dentry);
}
}
return ret;
}
+/* Caller holds the mutex of the item's inode */
static void configfs_detach_item(struct config_item *item)
{
detach_attrs(item);
sd = dentry->d_fsdata;
sd->s_type |= CONFIGFS_USET_DIR;
+ /*
+ * FYI, we're faking mkdir in populate_groups()
+ * We must lock the group's inode to avoid races with the VFS
+ * which can already hit the inode and try to add/remove entries
+ * under it.
+ *
+ * We must also lock the inode to remove it safely in case of
+ * error, as rmdir() would.
+ */
+ mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
ret = populate_groups(to_config_group(item));
if (ret) {
configfs_detach_item(item);
- d_delete(dentry);
+ dentry->d_inode->i_flags |= S_DEAD;
}
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ if (ret)
+ d_delete(dentry);
}
return ret;
}
+/* Caller holds the mutex of the group's inode */
static void configfs_detach_group(struct config_item *item)
{
detach_groups(to_config_group(item));
struct configfs_subsystem *subsys;
struct configfs_dirent *sd;
struct config_item_type *type;
- struct module *owner = NULL;
+ struct module *subsys_owner = NULL, *new_item_owner = NULL;
char *name;
if (dentry->d_parent == configfs_sb->s_root) {
goto out_put;
}
+ /*
+ * The subsystem may belong to a different module than the item
+ * being created. We don't want to safely pin the new item but
+ * fail to pin the subsystem it sits under.
+ */
+ if (!subsys->su_group.cg_item.ci_type) {
+ ret = -EINVAL;
+ goto out_put;
+ }
+ subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
+ if (!try_module_get(subsys_owner)) {
+ ret = -EINVAL;
+ goto out_put;
+ }
+
name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
if (!name) {
ret = -ENOMEM;
- goto out_put;
+ goto out_subsys_put;
}
snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
* If ret != 0, then link_obj() was never called.
* There are no extra references to clean up.
*/
- goto out_put;
+ goto out_subsys_put;
}
/*
goto out_unlink;
}
- owner = type->ct_owner;
- if (!try_module_get(owner)) {
+ new_item_owner = type->ct_owner;
+ if (!try_module_get(new_item_owner)) {
ret = -EINVAL;
goto out_unlink;
}
mutex_unlock(&subsys->su_mutex);
if (module_got)
- module_put(owner);
+ module_put(new_item_owner);
}
+out_subsys_put:
+ if (ret)
+ module_put(subsys_owner);
+
out_put:
/*
* link_obj()/link_group() took a reference from child->parent,
struct config_item *item;
struct configfs_subsystem *subsys;
struct configfs_dirent *sd;
- struct module *owner = NULL;
+ struct module *subsys_owner = NULL, *dead_item_owner = NULL;
int ret;
if (dentry->d_parent == configfs_sb->s_root)
return -EINVAL;
}
+ /* configfs_mkdir() shouldn't have allowed this */
+ BUG_ON(!subsys->su_group.cg_item.ci_type);
+ subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
+
/*
* Ensure that no racing symlink() will make detach_prep() fail while
* the new link is temporarily attached
*/
- mutex_lock(&configfs_symlink_mutex);
- spin_lock(&configfs_dirent_lock);
do {
struct mutex *wait_mutex;
+ mutex_lock(&configfs_symlink_mutex);
+ spin_lock(&configfs_dirent_lock);
ret = configfs_detach_prep(dentry, &wait_mutex);
- if (ret) {
+ if (ret)
configfs_detach_rollback(dentry);
- spin_unlock(&configfs_dirent_lock);
- mutex_unlock(&configfs_symlink_mutex);
+ spin_unlock(&configfs_dirent_lock);
+ mutex_unlock(&configfs_symlink_mutex);
+
+ if (ret) {
if (ret != -EAGAIN) {
config_item_put(parent_item);
return ret;
/* Wait until the racing operation terminates */
mutex_lock(wait_mutex);
mutex_unlock(wait_mutex);
-
- mutex_lock(&configfs_symlink_mutex);
- spin_lock(&configfs_dirent_lock);
}
} while (ret == -EAGAIN);
- spin_unlock(&configfs_dirent_lock);
- mutex_unlock(&configfs_symlink_mutex);
/* Get a working ref for the duration of this function */
item = configfs_get_config_item(dentry);
config_item_put(parent_item);
if (item->ci_type)
- owner = item->ci_type->ct_owner;
+ dead_item_owner = item->ci_type->ct_owner;
if (sd->s_type & CONFIGFS_USET_DIR) {
configfs_detach_group(item);
/* Drop our reference from above */
config_item_put(item);
- module_put(owner);
+ module_put(dead_item_owner);
+ module_put(subsys_owner);
return 0;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff