One user in mail list reported free space cache error where clear_cache
mount option failes to fix.
To reproduce such problem, add support to corrupt free space cache
file(old free space cache implement, or space_cache=v1).
With this patch, we can reproduce the problem quite easily:
Not suitable for a btrfs-progs or xfstest test case, as btrfsck won't
treat it as an error.
======
$ fallocate test.img -l 2G
$ mkfs.btrfs test.img
$ sudo mount test.img /mnt/btrfs/
$ sudo xfs_io -f -c "pwrite 0 16M" /mnt/btrfs/tmp
$ sudo umount /mnt/btrfs
$ ./btrfs-corrupt-block -s content -l 136708096 ../test.img
Here 136708096 is the second data chunk bytenr.
(The first data chunk is the 8M one from mkfs, which doesn't have free
space cache)
$ ./btrfsck test.img
Checking filesystem on ../test.img
UUID: 9542051b-8150-42e5-a9e6-95829656485c
checking extents
checking free space cache
btrfs: csum mismatch on free space cache <<< Found space cache problem
failed to load free space cache for block group 136708096
checking fs roots
checking csums
checking root refs
found 16941058 bytes used err is 0
total csum bytes: 16384
total tree bytes: 163840
total fs tree bytes: 32768
total extent tree bytes: 16384
btree space waste bytes: 139567
file data blocks allocated: 16908288
referenced 16908288
$ sudo mount -o clear_cache test.img /mnt/btrfs
$ sudo umount /mnt/btrfs
$ ./btrfsck test.img
Checking filesystem on ../test.img
UUID: 9542051b-8150-42e5-a9e6-95829656485c
checking extents
checking free space cache
btrfs: csum mismatch on free space cache <<< Problem not fixed by kernel
failed to load free space cache for block group 136708096
checking fs roots
checking csums
checking root refs
found 16941058 bytes used err is 0
total csum bytes: 16384
total tree bytes: 163840
total fs tree bytes: 32768
total extent tree bytes: 16384
btree space waste bytes: 139567
file data blocks allocated: 16908288
referenced 16908288
======
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");
+ 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;
+}
+
+#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;
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'},
{ "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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