This patch adds an option '--check-data-csum' to verify data csums.
fsck won't check data csums unless users specify this option explictly.
Signed-off-by: Wang Shilong <wangsl.f...@cn.fujitsu.com>
---
Documentation/btrfs-check.txt | 2 +
cmds-check.c | 122 ++++++++++++++++++++++++++++++++++++++++--
2 files changed, 120 insertions(+), 4 deletions(-)
diff --git a/Documentation/btrfs-check.txt b/Documentation/btrfs-check.txt
index 485a49c..bc10755 100644
--- a/Documentation/btrfs-check.txt
+++ b/Documentation/btrfs-check.txt
@@ -30,6 +30,8 @@ try to repair the filesystem.
create a new CRC tree.
--init-extent-tree::
create a new extent tree.
+--check-data-csum::
+check data csums.
EXIT STATUS
-----------
diff --git a/cmds-check.c b/cmds-check.c
index 103efc5..b53d49c 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -53,6 +53,7 @@ static LIST_HEAD(delete_items);
static int repair = 0;
static int no_holes = 0;
static int init_extent_tree = 0;
+static int check_data_csum = 0;
struct extent_backref {
struct list_head list;
@@ -3634,6 +3635,106 @@ static int check_space_cache(struct btrfs_root *root)
return error ? -EINVAL : 0;
}
+static int read_extent_data(struct btrfs_root *root, char *data,
+ u64 logical, u64 len, int mirror)
+{
+ u64 offset = 0;
+ struct btrfs_multi_bio *multi = NULL;
+ struct btrfs_fs_info *info = root->fs_info;
+ struct btrfs_device *device;
+ int ret = 0;
+ u64 read_len;
+ unsigned long bytes_left = len;
+
+ while (bytes_left) {
+ read_len = bytes_left;
+ device = NULL;
+ ret = btrfs_map_block(&info->mapping_tree, READ,
+ logical + offset, &read_len, &multi,
+ mirror, NULL);
+ if (ret) {
+ fprintf(stderr, "Couldn't map the block %llu\n",
+ logical + offset);
+ goto error;
+ }
+ device = multi->stripes[0].dev;
+
+ if (device->fd == 0)
+ goto error;
+
+ if (read_len > root->sectorsize)
+ read_len = root->sectorsize;
+ if (read_len > bytes_left)
+ read_len = bytes_left;
+
+ ret = pread64(device->fd, data + offset, read_len,
+ multi->stripes[0].physical);
+ if (ret != read_len)
+ goto error;
+ offset += read_len;
+ bytes_left -= read_len;
+ kfree(multi);
+ multi = NULL;
+ }
+ return 0;
+error:
+ kfree(multi);
+ return -EIO;
+}
+
+static int check_extent_csums(struct btrfs_root *root, u64 bytenr,
+ u64 num_bytes, unsigned long leaf_offset,
+ struct extent_buffer *eb) {
+
+ u64 offset = 0;
+ u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
+ char *data;
+ u32 crc;
+ unsigned long tmp;
+ char result[csum_size];
+ char out[csum_size];
+ int ret = 0;
+ __s64 cmp;
+ int mirror;
+ int num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
+ bytenr, num_bytes);
+
+ BUG_ON(num_bytes % root->sectorsize);
+ data = malloc(root->sectorsize);
+ if (!data)
+ return -ENOMEM;
+
+ while (offset < num_bytes) {
+ mirror = 0;
+again:
+ ret = read_extent_data(root, data, bytenr + offset,
+ root->sectorsize, mirror);
+ if (ret)
+ goto out;
+
+ crc = ~(u32)0;
+ crc = btrfs_csum_data(NULL, (char *)data, crc,
+ root->sectorsize);
+ btrfs_csum_final(crc, result);
+
+ tmp = leaf_offset + offset / root->sectorsize * csum_size;
+ read_extent_buffer(eb, out, tmp, csum_size);
+ cmp = memcmp(out, result, csum_size);
+ if (cmp) {
+ fprintf(stderr, "mirror: %d range bytenr: %llu, len: %d
checksum mismatch\n",
+ mirror, bytenr + offset, root->sectorsize);
+ if (mirror < num_copies - 1) {
+ mirror += 1;
+ goto again;
+ }
+ }
+ offset += root->sectorsize;
+ }
+out:
+ free(data);
+ return ret;
+}
+
static int check_extent_exists(struct btrfs_root *root, u64 bytenr,
u64 num_bytes)
{
@@ -3771,6 +3872,8 @@ static int check_csums(struct btrfs_root *root)
u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
int errors = 0;
int ret;
+ u64 data_len;
+ unsigned long leaf_offset;
root = root->fs_info->csum_root;
@@ -3812,6 +3915,16 @@ static int check_csums(struct btrfs_root *root)
continue;
}
+ data_len = (btrfs_item_size_nr(leaf, path->slots[0]) /
+ csum_size) * root->sectorsize;
+ if (!check_data_csum)
+ goto skip_csum_check;
+ leaf_offset = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ ret = check_extent_csums(root, key.offset, data_len,
+ leaf_offset, leaf);
+ if (ret)
+ break;
+skip_csum_check:
if (!num_bytes) {
offset = key.offset;
} else if (key.offset != offset + num_bytes) {
@@ -3825,9 +3938,7 @@ static int check_csums(struct btrfs_root *root)
offset = key.offset;
num_bytes = 0;
}
-
- num_bytes += (btrfs_item_size_nr(leaf, path->slots[0]) /
- csum_size) * root->sectorsize;
+ num_bytes += data_len;
path->slots[0]++;
}
@@ -6665,6 +6776,7 @@ static struct option long_options[] = {
{ "repair", 0, NULL, 0 },
{ "init-csum-tree", 0, NULL, 0 },
{ "init-extent-tree", 0, NULL, 0 },
+ { "check-data-csum", 0, NULL, 0 },
{ "backup", 0, NULL, 0 },
{ NULL, 0, NULL, 0}
};
@@ -6678,6 +6790,7 @@ const char * const cmd_check_usage[] = {
"--repair try to repair the filesystem",
"--init-csum-tree create a new CRC tree",
"--init-extent-tree create a new extent tree",
+ "--check-data-csum check data csums",
NULL
};
@@ -6736,8 +6849,9 @@ int cmd_check(int argc, char **argv)
ctree_flags |= (OPEN_CTREE_WRITES |
OPEN_CTREE_NO_BLOCK_GROUPS);
repair = 1;
+ } else if (option_index == 4) {
+ check_data_csum = 1;
}
-
}
argc = argc - optind;
--
1.9.0
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
