ext4: fix ext4_xattr_move_to_block()

When moving xattr entries from inline area to a xattr block, entries
that refer to external xattr inodes need special handling because
value data is not available in the inline area but rather should be
read from its external inode.
Signed-off-by: NTahsin Erdogan <tahsin@google.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

fs/ext4/xattr.c

@@ -1656,18 +1656,16 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
 	struct ext4_xattr_ibody_find *is = NULL;
 	struct ext4_xattr_block_find *bs = NULL;
 	char *buffer = NULL, *b_entry_name = NULL;
-	size_t value_offs, value_size;
+	size_t value_size = le32_to_cpu(entry->e_value_size);
 	struct ext4_xattr_info i = {
 		.value = NULL,
 		.value_len = 0,
 		.name_index = entry->e_name_index,
+		.in_inode = !!entry->e_value_inum,
 	};
 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
 	int error;
 
-	value_offs = le16_to_cpu(entry->e_value_offs);
-	value_size = le32_to_cpu(entry->e_value_size);
-
 	is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
 	bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
 	buffer = kmalloc(value_size, GFP_NOFS);
@@ -1683,7 +1681,17 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
 	bs->bh = NULL;
 
 	/* Save the entry name and the entry value */
-	memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
+	if (entry->e_value_inum) {
+		error = ext4_xattr_inode_get(inode,
+					     le32_to_cpu(entry->e_value_inum),
+					     buffer, value_size);
+		if (error)
+			goto out;
+	} else {
+		size_t value_offs = le16_to_cpu(entry->e_value_offs);
+		memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
+	}
+
 	memcpy(b_entry_name, entry->e_name, entry->e_name_len);
 	b_entry_name[entry->e_name_len] = '\0';
 	i.name = b_entry_name;
@@ -1701,7 +1709,6 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
 	if (error)
 		goto out;
 
-	i.name = b_entry_name;
 	i.value = buffer;
 	i.value_len = value_size;
 	error = ext4_xattr_block_find(inode, &i, bs);