f2fs: add F2FS_INLINE_DOTS to recover missing dot dentries

If f2fs was corrupted with missing dot dentries, it needs to recover them after
fsck.f2fs detection.

The underlying precedure is:

1. The fsck.f2fs remains F2FS_INLINE_DOTS flag in directory inode, if it detects
missing dot dentries.

2. When f2fs looks up the corrupted directory, it triggers f2fs_add_link with
proper inode numbers and their dot and dotdot names.

3. Once f2fs recovers the directory without errors, it removes F2FS_INLINE_DOTS
finally.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 8241a87..8140e4f 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -390,7 +390,7 @@
 }
 
 int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
-						struct inode *inode)
+			struct inode *inode, nid_t ino, umode_t mode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct page *ipage;
@@ -400,7 +400,7 @@
 	struct f2fs_inline_dentry *dentry_blk = NULL;
 	struct f2fs_dentry_ptr d;
 	int slots = GET_DENTRY_SLOTS(namelen);
-	struct page *page;
+	struct page *page = NULL;
 	int err = 0;
 
 	ipage = get_node_page(sbi, dir->i_ino);
@@ -417,29 +417,34 @@
 		goto out;
 	}
 
-	down_write(&F2FS_I(inode)->i_sem);
-	page = init_inode_metadata(inode, dir, name, ipage);
-	if (IS_ERR(page)) {
-		err = PTR_ERR(page);
-		goto fail;
+	if (inode) {
+		down_write(&F2FS_I(inode)->i_sem);
+		page = init_inode_metadata(inode, dir, name, ipage);
+		if (IS_ERR(page)) {
+			err = PTR_ERR(page);
+			goto fail;
+		}
 	}
 
 	f2fs_wait_on_page_writeback(ipage, NODE);
 
 	name_hash = f2fs_dentry_hash(name);
 	make_dentry_ptr(&d, (void *)dentry_blk, 2);
-	f2fs_update_dentry(inode, &d, name, name_hash, bit_pos);
+	f2fs_update_dentry(ino, mode, &d, name, name_hash, bit_pos);
 
 	set_page_dirty(ipage);
 
 	/* we don't need to mark_inode_dirty now */
-	F2FS_I(inode)->i_pino = dir->i_ino;
-	update_inode(inode, page);
-	f2fs_put_page(page, 1);
+	if (inode) {
+		F2FS_I(inode)->i_pino = dir->i_ino;
+		update_inode(inode, page);
+		f2fs_put_page(page, 1);
+	}
 
 	update_parent_metadata(dir, inode, 0);
 fail:
-	up_write(&F2FS_I(inode)->i_sem);
+	if (inode)
+		up_write(&F2FS_I(inode)->i_sem);
 
 	if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
 		update_inode(dir, ipage);