[PATCH 2/2] btrfs-progs: expand corrupt_file_extent in btrfs-corrupt-block

[Boris Burkov <boris@bur.io>]

To corrupt holes/prealloc/inline extents, we need to mess with
extent data items. This patch makes it possible to modify
disk_bytenr with a specific value (useful for hole corruptions)
and to modify the type field (useful for prealloc corruptions)

Signed-off-by: Boris Burkov <boris@bur.io>
---
 btrfs-corrupt-block.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/btrfs-corrupt-block.c b/btrfs-corrupt-block.c
index bf1ce9c5..40d8ad8e 100644
--- a/btrfs-corrupt-block.c
+++ b/btrfs-corrupt-block.c
@@ -323,6 +323,7 @@ enum btrfs_inode_field {
 
 enum btrfs_file_extent_field {
 	BTRFS_FILE_EXTENT_DISK_BYTENR,
+	BTRFS_FILE_EXTENT_TYPE,
 	BTRFS_FILE_EXTENT_BAD,
 };
 
@@ -377,6 +378,8 @@ static enum btrfs_file_extent_field convert_file_extent_field(char *field)
 {
 	if (!strncmp(field, "disk_bytenr", FIELD_BUF_LEN))
 		return BTRFS_FILE_EXTENT_DISK_BYTENR;
+	if (!strncmp(field, "type", FIELD_BUF_LEN))
+		return BTRFS_FILE_EXTENT_TYPE;
 	return BTRFS_FILE_EXTENT_BAD;
 }
 
@@ -673,14 +676,14 @@ out:
 
 static int corrupt_file_extent(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root, u64 inode, u64 extent,
-			       char *field)
+			       char *field, u64 bogus)
 {
 	struct btrfs_file_extent_item *fi;
 	struct btrfs_path *path;
 	struct btrfs_key key;
 	enum btrfs_file_extent_field corrupt_field;
-	u64 bogus;
 	u64 orig;
+	u8 bogus_type = bogus;
 	int ret = 0;
 
 	corrupt_field = convert_file_extent_field(field);
@@ -712,9 +715,18 @@ static int corrupt_file_extent(struct btrfs_trans_handle *trans,
 	switch (corrupt_field) {
 	case BTRFS_FILE_EXTENT_DISK_BYTENR:
 		orig = btrfs_file_extent_disk_bytenr(path->nodes[0], fi);
-		bogus = generate_u64(orig);
+		if (bogus == (u64)-1)
+			bogus = generate_u64(orig);
 		btrfs_set_file_extent_disk_bytenr(path->nodes[0], fi, bogus);
 		break;
+	case BTRFS_FILE_EXTENT_TYPE:
+		if (bogus == (u64)-1) {
+			fprintf(stderr, "Specify a new extent type value (-v)\n");
+			ret = -EINVAL;
+			goto out;
+		}
+		btrfs_set_file_extent_type(path->nodes[0], fi, bogus_type);
+		break;
 	default:
 		ret = -EINVAL;
 		break;
@@ -1394,9 +1406,9 @@ int main(int argc, char **argv)
 			printf("corrupting inode\n");
 			ret = corrupt_inode(trans, root, inode, field);
 		} else {
-			printf("corrupting file extent\n");
 			ret = corrupt_file_extent(trans, root, inode,
-						  file_extent, field);
+						  file_extent, field,
+						  bogus_value);
 		}
 		btrfs_commit_transaction(trans, root);
 		goto out_close;
-- 
2.24.1