btrfs-corrupt-block: add -e option to corrupt the extent record

This will zero out the extent allocation tree records for the extent.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/btrfs-corrupt-block.c b/btrfs-corrupt-block.c
index ace61c1..59e7cb4 100644 (file)
--- a/btrfs-corrupt-block.c
+++ b/btrfs-corrupt-block.c
@@ -32,11 +32,6 @@
 #include "list.h"
 #include "version.h"
 
-/* we write the mirror info to stdout unless they are dumping the data
- * to stdout
- * */
-static FILE *info_file;
-
 struct extent_buffer *debug_corrupt_block(struct btrfs_root *root, u64 bytenr,
                                     u32 blocksize, int copy)
 {
@@ -62,7 +57,7 @@ struct extent_buffer *debug_corrupt_block(struct btrfs_root *root, u64 bytenr,
                device->total_ios++;
                eb->dev_bytenr = multi->stripes[0].physical;
 
-               fprintf(info_file, "mirror %d logical %Lu physical %Lu "
+               fprintf(stdout, "mirror %d logical %Lu physical %Lu "
                        "device %s\n", mirror_num, (unsigned long long)bytenr,
                        (unsigned long long)eb->dev_bytenr, device->name);
                kfree(multi);
@@ -106,24 +101,88 @@ static struct option long_options[] = {
        { 0, 0, 0, 0}
 };
 
+static int corrupt_extent(struct btrfs_root *root, u64 bytenr, int copy)
+{
+       struct btrfs_trans_handle *trans;
+       struct btrfs_key key;
+       struct extent_buffer *leaf;
+       u32 item_size;
+       unsigned long ptr;
+       struct btrfs_path *path;
+       int ret;
+       int slot;
+
+       trans = btrfs_start_transaction(root, 1);
+       path = btrfs_alloc_path();
+
+       key.objectid = bytenr;
+       key.type = (u8)-1;
+       key.offset = (u64)-1;
+
+       while(1) {
+               ret = btrfs_search_slot(trans, root->fs_info->extent_root,
+                                       &key, path, 0, 1);
+               if (ret < 0)
+                       break;
+
+               if (ret > 0) {
+                       if (path->slots[0] == 0)
+                               break;
+                       path->slots[0]--;
+               }
+               leaf = path->nodes[0];
+               slot = path->slots[0];
+               btrfs_item_key_to_cpu(leaf, &key, slot);
+               if (key.objectid != bytenr)
+                       break;
+
+               if (key.type != BTRFS_EXTENT_ITEM_KEY &&
+                   key.type != BTRFS_TREE_BLOCK_REF_KEY &&
+                   key.type != BTRFS_EXTENT_DATA_REF_KEY &&
+                   key.type != BTRFS_EXTENT_REF_V0_KEY &&
+                   key.type != BTRFS_SHARED_BLOCK_REF_KEY &&
+                   key.type != BTRFS_SHARED_DATA_REF_KEY)
+                       goto next;
+
+               fprintf(stderr, "corrupting extent record: key %Lu %u %Lu\n",
+                       key.objectid, key.type, key.offset);
+
+               ptr = btrfs_item_ptr_offset(leaf, slot);
+               item_size = btrfs_item_size_nr(leaf, slot);
+               memset_extent_buffer(leaf, 0, ptr, item_size);
+               btrfs_mark_buffer_dirty(leaf);
+next:
+               btrfs_release_path(NULL, path);
+
+               if (key.offset > 0)
+                       key.offset--;
+               if (key.offset == 0)
+                       break;
+       }
+
+       btrfs_free_path(path);
+       btrfs_commit_transaction(trans, root);
+       ret = close_ctree(root);
+       BUG_ON(ret);
+       return 0;
+}
+
 int main(int ac, char **av)
 {
        struct cache_tree root_cache;
        struct btrfs_root *root;
        struct extent_buffer *eb;
        char *dev;
-       char *output_file = NULL;
        u64 logical = 0;
        int ret = 0;
        int option_index = 0;
        int copy = 0;
        u64 bytes = 4096;
-       int out_fd = 0;
-       int err;
+       int extent_rec;
 
        while(1) {
                int c;
-               c = getopt_long(ac, av, "l:c:", long_options,
+               c = getopt_long(ac, av, "l:c:e", long_options,
                                &option_index);
                if (c < 0)
                        break;
@@ -152,6 +211,9 @@ int main(int ac, char **av)
                                        print_usage();
                                }
                                break;
+                       case 'e':
+                               extent_rec = 1;
+                               break;
                        default:
                                print_usage();
                }
@@ -174,23 +236,9 @@ int main(int ac, char **av)
                fprintf(stderr, "Open ctree failed\n");
                exit(1);
        }
-
-       info_file = stdout;
-       if (output_file) {
-               if (strcmp(output_file, "-") == 0) {
-                       out_fd = 1;
-                       info_file = stderr;
-               } else {
-                       out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
-                       if (out_fd < 0)
-                               goto close;
-                       err = ftruncate(out_fd, 0);
-                       if (err) {
-                               close(out_fd);
-                               goto close;
-                       }
-                       info_file = stdout;
-               }
+       if (extent_rec) {
+               ret = corrupt_extent (root, logical, 0);
+               goto out;
        }
 
        if (bytes == 0)
@@ -201,21 +249,10 @@ int main(int ac, char **av)
 
        while (bytes > 0) {
                eb = debug_corrupt_block(root, logical, root->sectorsize, copy);
-               if (eb && output_file) {
-                       err = write(out_fd, eb->data, eb->len);
-                       if (err < 0 || err != eb->len) {
-                               fprintf(stderr, "output file write failed\n");
-                               goto out_close_fd;
-                       }
-               }
                free_extent_buffer(eb);
                logical += root->sectorsize;
                bytes -= root->sectorsize;
        }
-
-out_close_fd:
-       if (output_file && out_fd != 1)
-               close(out_fd);
-close:
+out:
        return ret;
 }