+/**
+ * Get a truncate lock
+ *
+ * In order to take multi-transaction truncate out of main transaction we let
+ * the caller grab a lock on the object passed. the lock can be shared (for
+ * writes) and exclusive (for truncate). It's not allowed to mix truncate
+ * and write in the same transaction handle (do not confuse with big ldiskfs
+ * transaction containing lots of handles).
+ * The lock must be taken at declaration.
+ *
+ * \param obj object to lock
+ * \oh transaction
+ * \shared shared or exclusive
+ *
+ * \retval 0 lock is granted
+ * \retval -NOMEM no memory to allocate lock
+ */
+int osd_trunc_lock(struct osd_object *obj, struct osd_thandle *oh, bool shared)
+{
+ struct osd_access_lock *al, *tmp;
+
+ LASSERT(obj);
+ LASSERT(oh);
+
+ list_for_each_entry(tmp, &oh->ot_trunc_locks, tl_list) {
+ if (tmp->tl_obj != obj)
+ continue;
+ LASSERT(tmp->tl_shared == shared);
+ /* found same lock */
+ return 0;
+ }
+
+ OBD_ALLOC_PTR(al);
+ if (unlikely(al == NULL))
+ return -ENOMEM;
+ al->tl_obj = obj;
+ al->tl_truncate = false;
+ if (shared)
+ down_read(&obj->oo_ext_idx_sem);
+ else
+ down_write(&obj->oo_ext_idx_sem);
+ al->tl_shared = shared;
+
+ list_add(&al->tl_list, &oh->ot_trunc_locks);
+
+ return 0;
+}
+
+void osd_trunc_unlock_all(struct list_head *list)
+{
+ struct osd_access_lock *al, *tmp;
+ list_for_each_entry_safe(al, tmp, list, tl_list) {
+ if (al->tl_shared)
+ up_read(&al->tl_obj->oo_ext_idx_sem);
+ else
+ up_write(&al->tl_obj->oo_ext_idx_sem);
+ list_del(&al->tl_list);
+ OBD_FREE_PTR(al);
+ }
+}
+
+void osd_execute_truncate(struct osd_object *obj)
+{
+ struct inode *inode = obj->oo_inode;
+ __u64 size;
+
+ /* simulate crash before (in the middle) of delayed truncate */
+ if (OBD_FAIL_CHECK(OBD_FAIL_OSD_FAIL_AT_TRUNCATE)) {
+ struct ldiskfs_inode_info *ei = LDISKFS_I(inode);
+ struct ldiskfs_sb_info *sbi = LDISKFS_SB(inode->i_sb);
+
+ mutex_lock(&sbi->s_orphan_lock);
+ list_del_init(&ei->i_orphan);
+ mutex_unlock(&sbi->s_orphan_lock);
+ return;
+ }
+
+#ifdef HAVE_INODEOPS_TRUNCATE
+ if (inode->i_op->truncate)
+ inode->i_op->truncate(inode);
+ else
+#endif
+ ldiskfs_truncate(inode);
+
+ /*
+ * For a partial-page truncate, flush the page to disk immediately to
+ * avoid data corruption during direct disk write. b=17397
+ */
+ size = i_size_read(inode);
+ if ((size & ~PAGE_MASK) != 0)
+ filemap_fdatawrite_range(inode->i_mapping, size, size + 1);
+}
+
+void osd_process_truncates(struct list_head *list)
+{
+ struct osd_access_lock *al;
+
+ LASSERT(journal_current_handle() == NULL);
+
+ list_for_each_entry(al, list, tl_list) {
+ if (al->tl_shared)
+ continue;
+ if (!al->tl_truncate)
+ continue;
+ osd_execute_truncate(al->tl_obj);
+ }
+}