f2fs: fix to avoid accessing uninitialized field of inode page in is_alive()

If inode is newly created, inode page may not synchronize with inode cache,
so fields like .i_inline or .i_extra_isize could be wrong, in below call
path, we may access such wrong fields, result in failing to migrate valid
target block.

Thread A Thread B
- f2fs_create
- f2fs_add_link
- f2fs_add_dentry
- f2fs_init_inode_metadata
- f2fs_add_inline_entry
- f2fs_new_inode_page
- f2fs_put_page
: inode page wasn't updated with inode cache
- gc_data_segment
- is_alive
- f2fs_get_node_page
- datablock_addr
- offset_in_addr
: access uninitialized fields

Fixes: 7a2af766af15 ("f2fs: enhance on-disk inode structure scalability")
Signed-off-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/dir.c

···
 
 	if (inode) {
 		f2fs_i_pino_write(inode, dir->i_ino);
+
+		/* synchronize inode page's data from inode cache */
+		if (is_inode_flag_set(inode, FI_NEW_INODE))
+			f2fs_update_inode(inode, page);
+
 		f2fs_put_page(page, 1);
 	}
 

fs/f2fs/inline.c

···
 	/* we don't need to mark_inode_dirty now */
 	if (inode) {
 		f2fs_i_pino_write(inode, dir->i_ino);
+
+		/* synchronize inode page's data from inode cache */
+		if (is_inode_flag_set(inode, FI_NEW_INODE))
+			f2fs_update_inode(inode, page);
+
 		f2fs_put_page(page, 1);
 	}