f2fs: fix to release inode correctly

In following call stack, if unfortunately we lose all chances to truncate
inode page in remove_inode_page, eventually we will add the nid allocated
previously into free nid cache, this nid is with NID_NEW status and with
NEW_ADDR in its blkaddr pointer:

 - f2fs_create
  - f2fs_add_link
   - __f2fs_add_link
    - init_inode_metadata
     - new_inode_page
      - new_node_page
       - set_node_addr(, NEW_ADDR)
     - f2fs_init_acl   failed
     - remove_inode_page  failed
  - handle_failed_inode
   - remove_inode_page  failed
   - iput
    - f2fs_evict_inode
     - remove_inode_page  failed
     - alloc_nid_failed   cache a nid with valid blkaddr: NEW_ADDR

This may not only cause resource leak of previous inode, but also may cause
incorrect use of the previous blkaddr which is located in NO.nid node entry
when this nid is reused by others.

This patch tries to add this inode to orphan list if we fail to truncate
inode, so that we can obtain a second chance to release it in orphan
recovery flow.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -1687,7 +1687,7 @@ int get_dnode_of_data(struct dnode_of_data *, pgoff_t, int);
 int truncate_inode_blocks(struct inode *, pgoff_t);
 int truncate_xattr_node(struct inode *, struct page *);
 int wait_on_node_pages_writeback(struct f2fs_sb_info *, nid_t);
-void remove_inode_page(struct inode *);
+int remove_inode_page(struct inode *);
 struct page *new_inode_page(struct inode *);
 struct page *new_node_page(struct dnode_of_data *, unsigned int, struct page *);
 void ra_node_page(struct f2fs_sb_info *, nid_t);

fs/f2fs/inode.c

@@ -317,6 +317,7 @@ void f2fs_evict_inode(struct inode *inode)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 	nid_t xnid = fi->i_xattr_nid;
+	int err = 0;
 
 	/* some remained atomic pages should discarded */
 	if (f2fs_is_atomic_file(inode))
@@ -342,11 +343,13 @@ void f2fs_evict_inode(struct inode *inode)
 	i_size_write(inode, 0);
 
 	if (F2FS_HAS_BLOCKS(inode))
-		f2fs_truncate(inode, true);
+		err = f2fs_truncate(inode, true);
 
-	f2fs_lock_op(sbi);
-	remove_inode_page(inode);
-	f2fs_unlock_op(sbi);
+	if (!err) {
+		f2fs_lock_op(sbi);
+		err = remove_inode_page(inode);
+		f2fs_unlock_op(sbi);
+	}
 
 	sb_end_intwrite(inode->i_sb);
 no_delete:
@@ -362,9 +365,26 @@ no_delete:
 	if (is_inode_flag_set(fi, FI_UPDATE_WRITE))
 		add_dirty_inode(sbi, inode->i_ino, UPDATE_INO);
 	if (is_inode_flag_set(fi, FI_FREE_NID)) {
-		alloc_nid_failed(sbi, inode->i_ino);
+		if (err && err != -ENOENT)
+			alloc_nid_done(sbi, inode->i_ino);
+		else
+			alloc_nid_failed(sbi, inode->i_ino);
 		clear_inode_flag(fi, FI_FREE_NID);
 	}
+
+	if (err && err != -ENOENT) {
+		if (!exist_written_data(sbi, inode->i_ino, ORPHAN_INO)) {
+			/*
+			 * get here because we failed to release resource
+			 * of inode previously, reminder our user to run fsck
+			 * for fixing.
+			 */
+			set_sbi_flag(sbi, SBI_NEED_FSCK);
+			f2fs_msg(sbi->sb, KERN_WARNING,
+				"inode (ino:%lu) resource leak, run fsck "
+				"to fix this issue!", inode->i_ino);
+		}
+	}
 out_clear:
 #ifdef CONFIG_F2FS_FS_ENCRYPTION
 	if (fi->i_crypt_info)
@@ -377,6 +397,7 @@ out_clear:
 void handle_failed_inode(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	int err = 0;
 
 	clear_nlink(inode);
 	make_bad_inode(inode);
@@ -384,9 +405,27 @@ void handle_failed_inode(struct inode *inode)
 
 	i_size_write(inode, 0);
 	if (F2FS_HAS_BLOCKS(inode))
-		f2fs_truncate(inode, false);
+		err = f2fs_truncate(inode, false);
+
+	if (!err)
+		err = remove_inode_page(inode);
 
-	remove_inode_page(inode);
+	/*
+	 * if we skip truncate_node in remove_inode_page bacause we failed
+	 * before, it's better to find another way to release resource of
+	 * this inode (e.g. valid block count, node block or nid). Here we
+	 * choose to add this inode to orphan list, so that we can call iput
+	 * for releasing in orphan recovery flow.
+	 *
+	 * Note: we should add inode to orphan list before f2fs_unlock_op()
+	 * so we can prevent losing this orphan when encoutering checkpoint
+	 * and following suddenly power-off.
+	 */
+	if (err && err != -ENOENT) {
+		err = acquire_orphan_inode(sbi);
+		if (!err)
+			add_orphan_inode(sbi, inode->i_ino);
+	}
 
 	set_inode_flag(F2FS_I(inode), FI_FREE_NID);
 	f2fs_unlock_op(sbi);

fs/f2fs/node.c

@@ -902,17 +902,20 @@ int truncate_xattr_node(struct inode *inode, struct page *page)
  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
  * f2fs_unlock_op().
  */
-void remove_inode_page(struct inode *inode)
+int remove_inode_page(struct inode *inode)
 {
 	struct dnode_of_data dn;
+	int err;
 
 	set_new_dnode(&dn, inode, NULL, NULL, inode->i_ino);
-	if (get_dnode_of_data(&dn, 0, LOOKUP_NODE))
-		return;
+	err = get_dnode_of_data(&dn, 0, LOOKUP_NODE);
+	if (err)
+		return err;
 
-	if (truncate_xattr_node(inode, dn.inode_page)) {
+	err = truncate_xattr_node(inode, dn.inode_page);
+	if (err) {
 		f2fs_put_dnode(&dn);
-		return;
+		return err;
 	}
 
 	/* remove potential inline_data blocks */
@@ -926,6 +929,7 @@ void remove_inode_page(struct inode *inode)
 
 	/* will put inode & node pages */
 	truncate_node(&dn);
+	return 0;
 }
 
 struct page *new_inode_page(struct inode *inode)