diff options
Diffstat (limited to 'fs/configfs/symlink.c')
| -rw-r--r-- | fs/configfs/symlink.c | 73 |
1 files changed, 53 insertions, 20 deletions
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c index 78929ea84ff..cc9f2546ea4 100644 --- a/fs/configfs/symlink.c +++ b/fs/configfs/symlink.c @@ -27,10 +27,14 @@ #include <linux/fs.h> #include <linux/module.h> #include <linux/namei.h> +#include <linux/slab.h> #include <linux/configfs.h> #include "configfs_internal.h" +/* Protects attachments of new symlinks */ +DEFINE_MUTEX(configfs_symlink_mutex); + static int item_depth(struct config_item * item) { struct config_item * p = item; @@ -73,40 +77,55 @@ static int create_link(struct config_item *parent_item, struct configfs_symlink *sl; int ret; + ret = -ENOENT; + if (!configfs_dirent_is_ready(target_sd)) + goto out; ret = -ENOMEM; sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL); if (sl) { sl->sl_target = config_item_get(item); - /* FIXME: needs a lock, I'd bet */ + spin_lock(&configfs_dirent_lock); + if (target_sd->s_type & CONFIGFS_USET_DROPPING) { + spin_unlock(&configfs_dirent_lock); + config_item_put(item); + kfree(sl); + return -ENOENT; + } list_add(&sl->sl_list, &target_sd->s_links); + spin_unlock(&configfs_dirent_lock); ret = configfs_create_link(sl, parent_item->ci_dentry, dentry); if (ret) { + spin_lock(&configfs_dirent_lock); list_del_init(&sl->sl_list); + spin_unlock(&configfs_dirent_lock); config_item_put(item); kfree(sl); } } +out: return ret; } -static int get_target(const char *symname, struct nameidata *nd, - struct config_item **target) +static int get_target(const char *symname, struct path *path, + struct config_item **target, struct super_block *sb) { int ret; - ret = path_lookup(symname, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, nd); + ret = kern_path(symname, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, path); if (!ret) { - if (nd->path.dentry->d_sb == configfs_sb) { - *target = configfs_get_config_item(nd->path.dentry); + if (path->dentry->d_sb == sb) { + *target = configfs_get_config_item(path->dentry); if (!*target) { ret = -ENOENT; - path_put(&nd->path); + path_put(path); } - } else + } else { ret = -EPERM; + path_put(path); + } } return ret; @@ -116,32 +135,45 @@ static int get_target(const char *symname, struct nameidata *nd, int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { int ret; - struct nameidata nd; + struct path path; + struct configfs_dirent *sd; struct config_item *parent_item; - struct config_item *target_item; + struct config_item *target_item = NULL; struct config_item_type *type; - ret = -EPERM; /* What lack-of-symlink returns */ - if (dentry->d_parent == configfs_sb->s_root) + sd = dentry->d_parent->d_fsdata; + /* + * Fake invisibility if dir belongs to a group/default groups hierarchy + * being attached + */ + ret = -ENOENT; + if (!configfs_dirent_is_ready(sd)) goto out; parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; + ret = -EPERM; if (!type || !type->ct_item_ops || !type->ct_item_ops->allow_link) goto out_put; - ret = get_target(symname, &nd, &target_item); + ret = get_target(symname, &path, &target_item, dentry->d_sb); if (ret) goto out_put; ret = type->ct_item_ops->allow_link(parent_item, target_item); - if (!ret) + if (!ret) { + mutex_lock(&configfs_symlink_mutex); ret = create_link(parent_item, target_item, dentry); + mutex_unlock(&configfs_symlink_mutex); + if (ret && type->ct_item_ops->drop_link) + type->ct_item_ops->drop_link(parent_item, + target_item); + } config_item_put(target_item); - path_put(&nd.path); + path_put(&path); out_put: config_item_put(parent_item); @@ -162,14 +194,14 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry) if (!(sd->s_type & CONFIGFS_ITEM_LINK)) goto out; - BUG_ON(dentry->d_parent == configfs_sb->s_root); - sl = sd->s_element; parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; + spin_lock(&configfs_dirent_lock); list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); configfs_drop_dentry(sd, dentry->d_parent); dput(dentry); configfs_put(sd); @@ -184,8 +216,9 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry) type->ct_item_ops->drop_link(parent_item, sl->sl_target); - /* FIXME: Needs lock */ + spin_lock(&configfs_dirent_lock); list_del_init(&sl->sl_list); + spin_unlock(&configfs_dirent_lock); /* Put reference from create_link() */ config_item_put(sl->sl_target); @@ -210,13 +243,13 @@ static int configfs_get_target_path(struct config_item * item, struct config_ite if (size > PATH_MAX) return -ENAMETOOLONG; - pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size); + pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size); for (s = path; depth--; s += 3) strcpy(s,"../"); fill_item_path(target, path, size); - pr_debug("%s: path = '%s'\n", __FUNCTION__, path); + pr_debug("%s: path = '%s'\n", __func__, path); return 0; } |