Josef Bacik
2013-Oct-01 12:54 UTC
[PATCH] Btrfs-progs: add ability to corrupt metadata block fields
This patch allows us to garble the generation field of a metadata block. We
will search down to the block, set the bogus generation and write the block back
out. I used this for verifying a transid fix patch for btrfsck. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---
btrfs-corrupt-block.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 117 insertions(+), 3 deletions(-)
diff --git a/btrfs-corrupt-block.c b/btrfs-corrupt-block.c
index 1f54b36..2d76ceb 100644
--- a/btrfs-corrupt-block.c
+++ b/btrfs-corrupt-block.c
@@ -102,6 +102,8 @@ static void print_usage(void)
"the field to corrupt)\n");
fprintf(stderr, "\t-x The file extent item to corrupt (must also "
"specify -i for the inode and -f for the field to corrupt)\n");
+ fprintf(stderr, "\t-m The metadata block to corrupt (must also "
+ "specify -f for the field to corrupt)\n");
fprintf(stderr, "\t-f The field in the item to corrupt\n");
exit(1);
}
@@ -138,7 +140,9 @@ static void corrupt_keys(struct btrfs_trans_handle *trans,
}
btrfs_mark_buffer_dirty(eb);
if (!trans) {
- csum_tree_block(root, eb, 0);
+ u16 csum_size + btrfs_super_csum_size(root->fs_info->super_copy);
+ csum_tree_block_size(eb, csum_size, 0);
write_extent_to_disk(eb);
}
}
@@ -296,6 +300,11 @@ enum btrfs_file_extent_field {
BTRFS_FILE_EXTENT_BAD,
};
+enum btrfs_metadata_block_field {
+ BTRFS_METADATA_BLOCK_GENERATION,
+ BTRFS_METADATA_BLOCK_BAD,
+};
+
static enum btrfs_inode_field convert_inode_field(char *field)
{
if (!strncmp(field, "isize", FIELD_BUF_LEN))
@@ -310,6 +319,14 @@ static enum btrfs_file_extent_field
convert_file_extent_field(char *field)
return BTRFS_FILE_EXTENT_BAD;
}
+static enum btrfs_metadata_block_field
+convert_metadata_block_field(char *field)
+{
+ if (!strncmp(field, "generation", FIELD_BUF_LEN))
+ return BTRFS_METADATA_BLOCK_GENERATION;
+ return BTRFS_METADATA_BLOCK_BAD;
+}
+
static u64 generate_u64(u64 orig)
{
u64 ret;
@@ -435,6 +452,87 @@ out:
return ret;
}
+static int corrupt_metadata_block(struct btrfs_root *root, u64 block,
+ char *field)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_path *path;
+ struct extent_buffer *eb;
+ struct btrfs_key key, root_key;
+ enum btrfs_metadata_block_field corrupt_field;
+ u64 root_objectid;
+ u64 orig, bogus;
+ u8 level;
+ int ret;
+
+ corrupt_field = convert_metadata_block_field(field);
+ if (corrupt_field == BTRFS_METADATA_BLOCK_BAD) {
+ fprintf(stderr, "Invalid field %s\n", field);
+ return -EINVAL;
+ }
+
+ eb = read_tree_block(root, block, root->leafsize, 0);
+ if (!eb) {
+ fprintf(stderr, "Couldn''t read in tree block %s\n",
field);
+ return -EINVAL;
+ }
+ root_objectid = btrfs_header_owner(eb);
+ level = btrfs_header_level(eb);
+ if (level)
+ btrfs_node_key_to_cpu(eb, &key, 0);
+ else
+ btrfs_item_key_to_cpu(eb, &key, 0);
+ free_extent_buffer(eb);
+
+ root_key.objectid = root_objectid;
+ root_key.type = BTRFS_ROOT_ITEM_KEY;
+ root_key.offset = (u64)-1;
+
+ root = btrfs_read_fs_root(root->fs_info, &root_key);
+ if (IS_ERR(root)) {
+ fprintf(stderr, "Couldn''t finde owner root %llu\n",
+ key.objectid);
+ return PTR_ERR(root);
+ }
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ btrfs_free_path(path);
+ fprintf(stderr, "Couldn''t start transaction %ld\n",
+ PTR_ERR(trans));
+ return PTR_ERR(trans);
+ }
+
+ path->lowest_level = level;
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+ if (ret < 0) {
+ fprintf(stderr, "Error searching to node %d\n", ret);
+ goto out;
+ }
+ eb = path->nodes[level];
+
+ ret = 0;
+ switch (corrupt_field) {
+ case BTRFS_METADATA_BLOCK_GENERATION:
+ orig = btrfs_header_generation(eb);
+ bogus = generate_u64(orig);
+ btrfs_set_header_generation(eb, bogus);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ btrfs_mark_buffer_dirty(path->nodes[level]);
+out:
+ btrfs_commit_transaction(trans, root);
+ btrfs_free_path(path);
+ return ret;
+}
+
static struct option long_options[] = {
/* { "byte-count", 1, NULL, ''b'' }, */
{ "logical", 1, NULL, ''l'' },
@@ -447,6 +545,7 @@ static struct option long_options[] = {
{ "chunk-tree", 0, NULL, ''U'' },
{ "inode", 1, NULL, ''i''},
{ "file-extent", 1, NULL, ''x''},
+ { "metadata-block", 1, NULL, ''m''},
{ "field", 1, NULL, ''f''},
{ 0, 0, 0, 0}
};
@@ -608,6 +707,7 @@ int main(int ac, char **av)
int corrupt_block_keys = 0;
int chunk_rec = 0;
int chunk_tree = 0;
+ u64 metadata_block = 0;
u64 inode = 0;
u64 file_extent = (u64)-1;
char field[FIELD_BUF_LEN];
@@ -617,7 +717,7 @@ int main(int ac, char **av)
while(1) {
int c;
- c = getopt_long(ac, av, "l:c:b:eEkuUi:f:x:", long_options,
+ c = getopt_long(ac, av, "l:c:b:eEkuUi:f:x:m:", long_options,
&option_index);
if (c < 0)
break;
@@ -675,6 +775,15 @@ int main(int ac, char **av)
print_usage();
}
break;
+ case ''m'':
+ errno = 0;
+ metadata_block = atoll(optarg);
+ if (errno) {
+ fprintf(stderr, "error converting "
+ "%d\n", errno);
+ print_usage();
+ }
+ break;
default:
print_usage();
}
@@ -760,7 +869,12 @@ int main(int ac, char **av)
btrfs_commit_transaction(trans, root);
goto out_close;
}
-
+ if (metadata_block) {
+ if (!strlen(field))
+ print_usage();
+ ret = corrupt_metadata_block(root, metadata_block, field);
+ goto out_close;
+ }
/*
* If we made it here and we have extent set then we didn''t specify
* inode and we''re screwed.
--
1.8.3.1
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