On 29.03.2018 13:37, Anand Jain wrote:
> During the scan context, we aren't verifying the superblock-
> checksum when read.
> This patch fixes it by adding the checksum verification function
> btrfs_check_super_csum() in the function btrfs_read_disk_super().
> And makes device scan to error fail if the primary superblock csum
> is wrong, whereas if the copy-superblock csum is wrong it will just
> just report mismatch and continue mount/scan as usual. When the
> mount is successful We anyway overwrite all superblocks upon unmount.
>
> The context in which this will be called is - device scan, device ready,
> and mount -o device option.
>
> Test script:
>
> Corrupt primary superblock and check if device scan and mount
> fails:
> mkfs.btrfs -fq /dev/sdc
> dd if=/dev/urandom of=/dev/sdc ibs=1 obs=1 count=1 seek=64K
> btrfs dev scan /dev/sdc
> mount /dev/sdc /btrfs
>
> Corrupt secondary superblock and check if device scan and mount
> is succcessful, check for the dmesg for errors.
> mkfs.btrfs -fq /dev/sdc
> dd if=/dev/urandom of=/dev/sdc ibs=1 obs=1 count=1 seek=67108864
> btrfs dev scan /dev/sdc
> mount /dev/sdc /btrfs
>
> Signed-off-by: Anand Jain <[email protected]>
> v3->v2:
> Also squash 4/8 in here.
> 4/8: btrfs: make btrfs_check_super_csum() non-static
> v1->v2:
> changed title.
> use explicit (< 0) check for %errr.
> Un-split pr_err() string.
> Fix typo in the git commit log.
> Move the csum check after bytenr and btrfs magic verified.
>
> btrfs: make btrfs_check_super_csum() non-static
>
> In preparation to add the superblock csum verification for the
> scan context, make btrfs_check_super_csum() non-static.
>
> Signed-off-by: Anand Jain <[email protected]>
> Reviewed-by: Nikolay Borisov <[email protected]>
This patch's changelog is garbaged. Duplicated signed off by ,
changelog above scissors etc. Please review your patches carefully
before sending upstream.
> ---
> fs/btrfs/disk-io.c | 2 +-
> fs/btrfs/disk-io.h | 1 +
> fs/btrfs/volumes.c | 13 +++++++++++++
> 3 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 4c573602480c..35dbbdc613cd 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -395,7 +395,7 @@ static int verify_parent_transid(struct extent_io_tree
> *io_tree,
> * Otherwise: -EINVAL if csum type is not found
> * -EUCLEAN if csum does not match
> */
> -static int btrfs_check_super_csum(char *raw_disk_sb)
> +int btrfs_check_super_csum(char *raw_disk_sb)
> {
> struct btrfs_super_block *disk_sb =
> (struct btrfs_super_block *)raw_disk_sb;
> diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
> index 70a88d61b547..c400cc68f913 100644
> --- a/fs/btrfs/disk-io.h
> +++ b/fs/btrfs/disk-io.h
> @@ -69,6 +69,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int
> max_mirrors);
> struct buffer_head *btrfs_read_dev_super(struct block_device *bdev);
> int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num,
> struct buffer_head **bh_ret);
> +int btrfs_check_super_csum(char *raw_disk_sb);
> int btrfs_commit_super(struct btrfs_fs_info *fs_info);
> struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
> struct btrfs_key *location);
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 035affa447fa..f1f074fbfee1 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -1149,6 +1149,7 @@ static int btrfs_read_disk_super(struct block_device
> *bdev, u64 bytenr,
> struct page **page,
> struct btrfs_super_block **disk_super)
> {
> + int err;
> void *p;
> pgoff_t index;
>
> @@ -1183,6 +1184,18 @@ static int btrfs_read_disk_super(struct block_device
> *bdev, u64 bytenr,
> return -EINVAL;
> }
>
> + err = btrfs_check_super_csum((char *) *disk_super);
> + if (err < 0) {
> + if (err == -EINVAL)
> + pr_err("BTRFS error (device %pg): unsupported checksum
> type, bytenr=%llu",
> + bdev, bytenr);
> + else
> + pr_err("BTRFS error (device %pg): superblock checksum
> failed, bytenr=%llu",
> + bdev, bytenr);
> + btrfs_release_disk_super(*page);
> + return err;
> + }
> +
> if ((*disk_super)->label[0] &&
> (*disk_super)->label[BTRFS_LABEL_SIZE - 1])
> (*disk_super)->label[BTRFS_LABEL_SIZE - 1] = '\0';
>
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