configfs: Prevent duplicate subsystem names.
For all child objects, creation comes through mkdir(2), so duplicate names
are prevented.
Subsystems, though, are registered by client drivers at init_module()/__init
time. This patch prevents duplicate subsystem names.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index df02545..816e8ef 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -86,6 +86,32 @@
return sd;
}
+/*
+ *
+ * Return -EEXIST if there is already a configfs element with the same
+ * name for the same parent.
+ *
+ * called with parent inode's i_mutex held
+ */
+int configfs_dirent_exists(struct configfs_dirent *parent_sd,
+ const unsigned char *new)
+{
+ struct configfs_dirent * sd;
+
+ list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+ if (sd->s_element) {
+ const unsigned char *existing = configfs_get_name(sd);
+ if (strcmp(existing, new))
+ continue;
+ else
+ return -EEXIST;
+ }
+ }
+
+ return 0;
+}
+
+
int configfs_make_dirent(struct configfs_dirent * parent_sd,
struct dentry * dentry, void * element,
umode_t mode, int type)
@@ -136,8 +162,10 @@
int error;
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
- error = configfs_make_dirent(p->d_fsdata, d, k, mode,
- CONFIGFS_DIR);
+ error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
+ if (!error)
+ error = configfs_make_dirent(p->d_fsdata, d, k, mode,
+ CONFIGFS_DIR);
if (!error) {
error = configfs_create(d, mode, init_dir);
if (!error) {