+
+
+static int yaffs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ int ret_val;
+
+ struct yaffs_dev *dev;
+ struct yaffs_obj *obj;
+
+ yaffs_trace(YAFFS_TRACE_OS, "yaffs_unlink %d:%s",
+ (int)(dir->i_ino), dentry->d_name.name);
+ obj = yaffs_inode_to_obj(dir);
+ dev = obj->my_dev;
+
+ yaffs_gross_lock(dev);
+
+ ret_val = yaffs_unlinker(obj, dentry->d_name.name);
+
+ if (ret_val == YAFFS_OK) {
+ inode_dec_link_count(dentry->d_inode);
+ dir->i_version++;
+ yaffs_gross_unlock(dev);
+ update_dir_time(dir);
+ return 0;
+ }
+ yaffs_gross_unlock(dev);
+ return -ENOTEMPTY;
+}
+
+
+
+static const struct inode_operations yaffs_dir_inode_operations = {
+ .create = yaffs_create,
+ .lookup = yaffs_lookup,
+ .link = yaffs_link,
+ .unlink = yaffs_unlink,
+ .symlink = yaffs_symlink,
+ .mkdir = yaffs_mkdir,
+ .rmdir = yaffs_unlink,
+ .mknod = yaffs_mknod,
+ .rename = yaffs_rename,
+ .setattr = yaffs_setattr,
+ .setxattr = yaffs_setxattr,
+ .getxattr = yaffs_getxattr,
+ .listxattr = yaffs_listxattr,
+ .removexattr = yaffs_removexattr,
+};
+
+/*-----------------------------------------------------------------*/
+/* Directory search context allows us to unlock access to yaffs during
+ * filldir without causing problems with the directory being modified.
+ * This is similar to the tried and tested mechanism used in yaffs direct.
+ *
+ * A search context iterates along a doubly linked list of siblings in the
+ * directory. If the iterating object is deleted then this would corrupt
+ * the list iteration, likely causing a crash. The search context avoids
+ * this by using the remove_obj_fn to move the search context to the
+ * next object before the object is deleted.
+ *
+ * Many readdirs (and thus seach conexts) may be alive simulateously so
+ * each struct yaffs_dev has a list of these.
+ *
+ * A seach context lives for the duration of a readdir.
+ *
+ * All these functions must be called while yaffs is locked.
+ */
+
+struct yaffs_search_context {
+ struct yaffs_dev *dev;
+ struct yaffs_obj *dir_obj;
+ struct yaffs_obj *next_return;
+ struct list_head others;
+};
+
+/*
+ * yaffs_new_search() creates a new search context, initialises it and
+ * adds it to the device's search context list.
+ *
+ * Called at start of readdir.
+ */
+static struct yaffs_search_context *yaffs_new_search(struct yaffs_obj *dir)
+{
+ struct yaffs_dev *dev = dir->my_dev;
+ struct yaffs_search_context *sc =
+ kmalloc(sizeof(struct yaffs_search_context), GFP_NOFS);
+ if (sc) {
+ sc->dir_obj = dir;
+ sc->dev = dev;
+ if (list_empty(&sc->dir_obj->variant.dir_variant.children))
+ sc->next_return = NULL;
+ else
+ sc->next_return =
+ list_entry(dir->variant.dir_variant.children.next,
+ struct yaffs_obj, siblings);
+ INIT_LIST_HEAD(&sc->others);
+ list_add(&sc->others, &(yaffs_dev_to_lc(dev)->search_contexts));
+ }
+ return sc;
+}
+
+/*
+ * yaffs_search_end() disposes of a search context and cleans up.
+ */
+static void yaffs_search_end(struct yaffs_search_context *sc)
+{
+ if (sc) {
+ list_del(&sc->others);
+ kfree(sc);
+ }
+}
+
+/*
+ * yaffs_search_advance() moves a search context to the next object.
+ * Called when the search iterates or when an object removal causes
+ * the search context to be moved to the next object.
+ */
+static void yaffs_search_advance(struct yaffs_search_context *sc)
+{
+ if (!sc)
+ return;
+
+ if (sc->next_return == NULL ||
+ list_empty(&sc->dir_obj->variant.dir_variant.children))
+ sc->next_return = NULL;
+ else {
+ struct list_head *next = sc->next_return->siblings.next;
+
+ if (next == &sc->dir_obj->variant.dir_variant.children)
+ sc->next_return = NULL; /* end of list */
+ else
+ sc->next_return =
+ list_entry(next, struct yaffs_obj, siblings);
+ }
+}
+
+/*
+ * yaffs_remove_obj_callback() is called when an object is unlinked.
+ * We check open search contexts and advance any which are currently
+ * on the object being iterated.
+ */
+static void yaffs_remove_obj_callback(struct yaffs_obj *obj)
+{
+
+ struct list_head *i;
+ struct yaffs_search_context *sc;
+ struct list_head *search_contexts =
+ &(yaffs_dev_to_lc(obj->my_dev)->search_contexts);
+
+ /* Iterate through the directory search contexts.
+ * If any are currently on the object being removed, then advance
+ * the search context to the next object to prevent a hanging pointer.
+ */
+ list_for_each(i, search_contexts) {
+ sc = list_entry(i, struct yaffs_search_context, others);
+ if (sc->next_return == obj)
+ yaffs_search_advance(sc);
+ }
+
+}
+
+
+/*-----------------------------------------------------------------*/
+