David Sterba wrote on 2016/05/17 15:00 +0200:
On Tue, May 17, 2016 at 11:47:55AM +0800, Qu Wenruo wrote:
Btrfs-progs fix will follow soon.
Reported-by: Ivan P <chrnosphe...@gmail.com>
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
btrfs-corrupt-block.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 123 insertions(+), 1 deletion(-)
diff --git a/btrfs-corrupt-block.c b/btrfs-corrupt-block.c
index d331f96..eb27265 100644
--- a/btrfs-corrupt-block.c
+++ b/btrfs-corrupt-block.c
@@ -115,6 +115,9 @@ static void print_usage(int ret)
fprintf(stderr, "\t-C Delete a csum for the specified bytenr. When "
"used with -b it'll delete that many bytes, otherwise it's "
"just sectorsize\n");
+ fprintf(stderr, "\t-s <method>\n");
No single letter option, this is too specialized. Also we'd need to
specify the free space cache version to clear and support only v1 for
now.
Originally planned as 2 different options, clear-space-cache-file for v1
and clear-space-cache-tree for v2.
But your advice is right, --space-cache v1|v2 is much better.
I'll use that method and move generation/content specification to -f
options.
+ fprintf(stderr, "\t Corrupt free space cache file(space_cache v1), must
also specify -l for blockgroup bytenr\n");
+ fprintf(stderr, "\t <method> can be 'zero_gen','rand_gen' or
'content'\n");
exit(ret);
}
@@ -1012,6 +1015,100 @@ out:
return ret;
}
+
+u64 rand_u64(void)
+{
+ u64 ret = 0;
+ int n;
+
+ for (n = 0; n < sizeof(ret) / sizeof(RAND_MAX); n++)
+ ret += rand() << (n * sizeof(RAND_MAX) * 8);
+ return ret;
+}
Please introduce the function in a separate patch and put it to utils.
The use of rand() in the code is quite random and coverity complains
about the wrong use, so I'd like to use this to a broader cleanup.
OK, as I just forgot the static prefix and I think that's the reason
compiler complains. (the only caller in main() has initialized the seed).
+
+#define CORRUPT_SC_FILE_ZERO_GEN 1
+#define CORRUPT_SC_FILE_RAND_GEN 2
+#define CORRUPT_SC_FILE_CONTENT 3
+int corrupt_space_cache_file(struct btrfs_fs_info *fs_info, u64 block_group,
+ int method)
+{
+ struct btrfs_root *tree_root = fs_info->tree_root;
+ struct btrfs_path path;
+ struct btrfs_key key;
+ struct btrfs_disk_key location;
+ struct btrfs_free_space_header *sc_header;
+ struct btrfs_file_extent_item *fi;
+ struct extent_buffer *node;
+ struct extent_buffer *corrupted_node;
+ u64 disk_bytenr;
+ int slot;
+ int ret;
+
+ key.objectid = BTRFS_FREE_SPACE_OBJECTID;
+ key.type = 0;
+ key.offset = block_group;
+
+ btrfs_init_path(&path);
+
+ /* Don't start trans, as this will cause generation different */
+ ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
+ if (ret) {
+ error("failed to find free space cahce file for block group %llu,
ret: %d\n",
+ block_group, ret);
+ goto out;
+ }
+ slot = path.slots[0];
+ node = path.nodes[0];
+ sc_header = btrfs_item_ptr(node, slot, struct btrfs_free_space_header);
+ if (method == CORRUPT_SC_FILE_ZERO_GEN ||
+ method == CORRUPT_SC_FILE_RAND_GEN) {
+ u64 dst_gen;
+
+ if (method == CORRUPT_SC_FILE_ZERO_GEN)
+ dst_gen = 0;
+ else
+ dst_gen = rand_u64();
+
+ btrfs_set_free_space_generation(node, sc_header, dst_gen);
+ /* Manually re-calc csum and write to disk */
+ ret = write_tree_block(NULL, tree_root, node);
+ goto out;
+ }
+
+ btrfs_free_space_key(node, sc_header, &location);
+ btrfs_disk_key_to_cpu(&key, &location);
+ btrfs_release_path(&path);
+
+ /* Change to type and offset to search file extent */
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
+ if (ret) {
+ error("failed to find free space cache extent data for blockgroup
%llu, ret: %d\n",
+ block_group, ret);
+ goto out;
+ }
+
+ slot = path.slots[0];
+ node = path.nodes[0];
+ fi = btrfs_item_ptr(node, slot, struct btrfs_file_extent_item);
+ disk_bytenr = btrfs_file_extent_disk_bytenr(node, fi);
+
+ /*
+ * Directly write random data into
+ * [disk_bytenr, disk_bytenr + sectorsize) as free space cache inode
+ * doesn't have csum
+ */
+ corrupted_node = debug_corrupt_block(tree_root, disk_bytenr,
+ tree_root->sectorsize, 0);
+ free_extent_buffer(corrupted_node);
+
+out:
+ btrfs_release_path(&path);
+ return ret;
+}
+
int main(int argc, char **argv)
{
struct cache_tree root_cache;
@@ -1032,6 +1129,7 @@ int main(int argc, char **argv)
int corrupt_item = 0;
int corrupt_di = 0;
int delete = 0;
+ int corrupt_sc_file = 0;
Why is it named _file?
Free space cache file (v1).
As v1 free space cache is implemented as a normal file with nodatacow.
Anyway, since I'll follow your suggestion to use "space-cache", there is
no "_file" then.
Thanks,
Qu
u64 metadata_block = 0;
u64 inode = 0;
u64 file_extent = (u64)-1;
@@ -1065,11 +1163,12 @@ int main(int argc, char **argv)
{ "delete", no_argument, NULL, 'd'},
{ "root", no_argument, NULL, 'r'},
{ "csum", required_argument, NULL, 'C'},
+ { "space-cache-file", required_argument, NULL, 's'},
"clear-free-space-cache" is quite long but more understandable IMHO
{ "help", no_argument, NULL, GETOPT_VAL_HELP},
{ NULL, 0, NULL, 0 }
};
- c = getopt_long(argc, argv, "l:c:b:eEkuUi:f:x:m:K:IDdr:C:",
+ c = getopt_long(argc, argv, "l:c:b:eEkuUi:f:x:m:K:IDdr:C:s:",
long_options, NULL);
if (c < 0)
break;
@@ -1136,6 +1235,22 @@ int main(int argc, char **argv)
case 'C':
csum_bytenr = arg_strtou64(optarg);
break;
+ case 's':
+ if (!strncmp(optarg, "zero_gen",
+ sizeof("zero_gen")))
+ corrupt_sc_file =
+ CORRUPT_SC_FILE_ZERO_GEN;
+ else if (!strncmp(optarg, "rand_gen",
+ sizeof("rand_gen")))
+ corrupt_sc_file =
+ CORRUPT_SC_FILE_RAND_GEN;
+ else if (!strncmp(optarg, "content",
+ sizeof("content")))
+ corrupt_sc_file =
+ CORRUPT_SC_FILE_CONTENT;
+ else
+ print_usage(1);
+ break;
case GETOPT_VAL_HELP:
default:
print_usage(c != GETOPT_VAL_HELP);
@@ -1154,6 +1269,13 @@ int main(int argc, char **argv)
fprintf(stderr, "Open ctree failed\n");
exit(1);
}
+ if (corrupt_sc_file) {
+ if (logical == (u64)-1)
+ print_usage(1);
+ ret = corrupt_space_cache_file(root->fs_info, logical,
+ corrupt_sc_file);
+ goto out_close;
+ }
if (extent_rec) {
struct btrfs_trans_handle *trans;
--
2.8.2
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