[PATCH 3.16 041/245] btrfs: Add checker for EXTENT_CSUM

Ben Hutchings
2020-04-23T23:24:01Z

From: Qu Wenruo <quwenruo.btrfs@gmx.com>

commit 4b865cab96fe2a30ed512cf667b354bd291b3b0a upstream.

EXTENT_CSUM checker is a relatively easy one, only needs to check:

1) Objectid
Fixed to BTRFS_EXTENT_CSUM_OBJECTID

2) Key offset alignment
Must be aligned to sectorsize

3) Item size alignedment
Must be aligned to csum size

Signed-off-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[bwh: Backported to 4.4: Use root->sectorsize instead of
root->fs_info->sectorsize]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/btrfs/disk-io.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -590,6 +590,27 @@ static int check_extent_data_item(struct
return 0;
}

+static int check_csum_item(struct btrfs_root *root, struct extent_buffer *leaf,
+ struct btrfs_key *key, int slot)
+{
+ u32 sectorsize = root->sectorsize;
+ u32 csumsize = btrfs_super_csum_size(root->fs_info->super_copy);
+
+ if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) {
+ CORRUPT("invalid objectid for csum item", leaf, root, slot);
+ return -EUCLEAN;
+ }
+ if (!IS_ALIGNED(key->offset, sectorsize)) {
+ CORRUPT("unaligned key offset for csum item", leaf, root, slot);
+ return -EUCLEAN;
+ }
+ if (!IS_ALIGNED(btrfs_item_size_nr(leaf, slot), csumsize)) {
+ CORRUPT("unaligned csum item size", leaf, root, slot);
+ return -EUCLEAN;
+ }
+ return 0;
+}
+
/*
* Common point to switch the item-specific validation.
*/
@@ -603,6 +624,9 @@ static int check_leaf_item(struct btrfs_
case BTRFS_EXTENT_DATA_KEY:
ret = check_extent_data_item(root, leaf, key, slot);
break;
+ case BTRFS_EXTENT_CSUM_KEY:
+ ret = check_csum_item(root, leaf, key, slot);
+ break;
}
return ret;
}