apfs: implement ->evict_inode() method

Implement the ->evict_inode() superblock operation, which must deal with
orphaned inode records and also their fake hardlinks under private-dir.

Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

fs/apfs/dir.c

@@ -996,6 +996,73 @@ fail:
 	return err;
 }
 
+/**
+ * apfs_delete_orphan_link - Delete the link for an orphan inode
+ * @inode: the vfs inode
+ *
+ * Returns 0 on success or a negative error code in case of failure.
+ */
+int apfs_delete_orphan_link(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct apfs_sb_info *sbi = APFS_SB(sb);
+	struct apfs_key key;
+	struct apfs_query *query;
+	struct apfs_inode_val *inode_val;
+	char *node_raw;
+	struct qstr qname;
+	struct apfs_drec drec;
+	struct apfs_inode_info parent_info;
+	int err;
+
+	err = apfs_orphan_name(inode, &qname);
+	if (err)
+		return err;
+
+	/*
+	 * XXX: fake the basic parent fields needed by apfs_dentry_lookup(); in
+	 * the future we'll use a real private-dir inode.
+	 */
+	parent_info.vfs_inode.i_sb = sb;
+	parent_info.vfs_inode.i_ino = APFS_PRIV_DIR_INO_NUM;
+#if BITS_PER_LONG == 32
+	parent_info.i_ino = APFS_PRIV_DIR_INO_NUM;
+#endif
+
+	query = apfs_dentry_lookup(&parent_info.vfs_inode, &qname, &drec);
+	if (IS_ERR(query)) {
+		err = PTR_ERR(query);
+		query = NULL;
+		goto fail;
+	}
+	err = apfs_btree_remove(query);
+	if (err)
+		goto fail;
+	apfs_free_query(sb, query);
+	query = NULL;
+
+	/* XXX: update the child count in the parent inode */
+	apfs_init_inode_key(APFS_PRIV_DIR_INO_NUM, &key);
+	query = apfs_alloc_query(sbi->s_cat_root, NULL /* parent */);
+	if (!query) {
+		err = -ENOMEM;
+		goto fail;
+	}
+	query->key = &key;
+	query->flags |= APFS_QUERY_CAT | APFS_QUERY_EXACT;
+	err = apfs_btree_query(sb, &query);
+	if (err)
+		goto fail;
+	node_raw = query->node->object.bh->b_data;
+	inode_val = (struct apfs_inode_val *)(node_raw + query->off);
+	le32_add_cpu(&inode_val->nchildren, -1);
+
+fail:
+	apfs_free_query(sb, query);
+	kfree(qname.name);
+	return err;
+}
+
 int apfs_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct super_block *sb = dir->i_sb;

fs/apfs/dir.h

@@ -64,6 +64,7 @@ extern int apfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 extern int apfs_link(struct dentry *old_dentry, struct inode *dir,
 		     struct dentry *dentry);
 extern int apfs_unlink(struct inode *dir, struct dentry *dentry);
+extern int apfs_delete_orphan_link(struct inode *inode);
 
 extern const struct file_operations apfs_dir_operations;
 

fs/apfs/inode.c

@@ -508,6 +508,71 @@ fail:
 	return err;
 }
 
+/**
+ * apfs_delete_inode - Delete an inode record and update the volume file count
+ * @inode: the vfs inode to delete
+ *
+ * Returns 0 on success or a negative error code in case of failure.
+ */
+static int apfs_delete_inode(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct apfs_sb_info *sbi = APFS_SB(sb);
+	struct apfs_superblock *vsb_raw = sbi->s_vsb_raw;
+	struct apfs_query *query;
+	int ret;
+
+	query = apfs_inode_lookup(inode);
+	if (IS_ERR(query))
+		return PTR_ERR(query);
+	ret = apfs_btree_remove(query);
+	apfs_free_query(sb, query);
+
+	ASSERT(sbi->s_xid == le64_to_cpu(vsb_raw->apfs_o.o_xid));
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		le64_add_cpu(&vsb_raw->apfs_num_files, -1);
+		break;
+	case S_IFDIR:
+		le64_add_cpu(&vsb_raw->apfs_num_directories, -1);
+		break;
+	case S_IFLNK:
+		le64_add_cpu(&vsb_raw->apfs_num_symlinks, -1);
+		break;
+	default:
+		le64_add_cpu(&vsb_raw->apfs_num_other_fsobjects, -1);
+		break;
+	}
+	return ret;
+}
+
+void apfs_evict_inode(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	if (is_bad_inode(inode) || inode->i_nlink)
+		goto out_clear;
+
+	if (apfs_transaction_start(sb))
+		goto out_report;
+	if (apfs_delete_inode(inode))
+		goto out_abort;
+	if (apfs_delete_orphan_link(inode))
+		goto out_abort;
+	if (apfs_transaction_commit(sb))
+		goto out_abort;
+	goto out_clear;
+
+out_abort:
+	apfs_transaction_abort(sb);
+out_report:
+	apfs_warn(sb,
+		  "failed to delete orphan inode 0x%llx\n", apfs_ino(inode));
+out_clear:
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+}
+
 /**
  * apfs_new_inode - Create a new in-memory inode
  * @dir:	parent inode

fs/apfs/inode.h

@@ -153,6 +153,7 @@ static inline u64 apfs_ino(const struct inode *inode)
 
 extern struct inode *apfs_iget(struct super_block *sb, u64 cnid);
 extern int apfs_update_inode(struct inode *inode, char *new_name);
+extern void apfs_evict_inode(struct inode *inode);
 extern int apfs_getattr(const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int query_flags);
 extern struct inode *apfs_new_inode(struct inode *dir, umode_t mode,

fs/apfs/super.c

@@ -693,6 +693,7 @@ static const struct super_operations apfs_sops = {
 	.alloc_inode	= apfs_alloc_inode,
 	.destroy_inode	= apfs_destroy_inode,
 	.write_inode	= apfs_write_inode,
+	.evict_inode	= apfs_evict_inode,
 	.put_super	= apfs_put_super,
 	.statfs		= apfs_statfs,
 	.show_options	= apfs_show_options,