udf: Set i_generation field

Currently UDF doesn't initialize i_generation in any way and thus NFS
can easily get reallocated inodes from stale file handles. Luckily UDF
already has a unique object identifier associated with each inode -
i_unique. Use that for initialization of i_generation.
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/ialloc.c

@@ -95,6 +95,7 @@ struct inode *udf_new_inode(struct inode *dir, umode_t mode, int *err)
 	lvidiu = udf_sb_lvidiu(sb);
 	if (lvidiu) {
 		iinfo->i_unique = lvid_get_unique_id(sb);
+		inode->i_generation = iinfo->i_unique;
 		mutex_lock(&sbi->s_alloc_mutex);
 		if (S_ISDIR(mode))
 			le32_add_cpu(&lvidiu->numDirs, 1);

fs/udf/inode.c

@@ -1484,6 +1484,7 @@ static int udf_read_inode(struct inode *inode)
 		iinfo->i_lenAlloc = le32_to_cpu(efe->lengthAllocDescs);
 		iinfo->i_checkpoint = le32_to_cpu(efe->checkpoint);
 	}
+	inode->i_generation = iinfo->i_unique;
 
 	switch (fe->icbTag.fileType) {
 	case ICBTAG_FILE_TYPE_DIRECTORY: