Re: [PATCH 12/17] btrfs: add boilerplate code for directly including the crypto framework

[Nikolay Borisov <nborisov@suse.com>]

On 10.05.19 г. 14:15 ч., Johannes Thumshirn wrote:
> Add boilerplate code for directly including the crypto framework.
> 
> This helps us flipping the switch for new algorithms.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  fs/btrfs/ctree.h   | 11 +++++++++++
>  fs/btrfs/disk-io.c | 49 ++++++++++++++++++++++++++++++++++++++++++-------
>  2 files changed, 53 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index e62934fb8748..8733c55ed686 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -73,6 +73,7 @@ struct btrfs_ref;
>  
>  /* four bytes for CRC32 */
>  static const int btrfs_csum_sizes[] = { 4 };
> +static char *btrfs_csum_names[] = { "crc32c" };
>  
>  #define BTRFS_EMPTY_DIR_SIZE 0
>  
> @@ -1165,6 +1166,8 @@ struct btrfs_fs_info {
>  	spinlock_t ref_verify_lock;
>  	struct rb_root block_tree;
>  #endif
> +
> +	struct crypto_shash *csum_shash;
>  };
>  
>  static inline struct btrfs_fs_info *btrfs_sb(struct super_block *sb)
> @@ -2452,6 +2455,14 @@ static inline int btrfs_super_csum_size(const struct btrfs_super_block *s)
>  	return btrfs_csum_sizes[t];
>  }
>  
> +static inline char *btrfs_super_csum_name(const struct btrfs_super_block *s)
> +{
> +	u16 t = btrfs_super_csum_type(s);
> +	/*
> +	 * csum type is validated at mount time
> +	 */
> +	return btrfs_csum_names[t];
> +}
>  
>  /*
>   * The leaf data grows from end-to-front in the node.
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 21ae9daf52b7..d57adf3eaa85 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -19,6 +19,7 @@
>  #include <linux/crc32c.h>
>  #include <linux/sched/mm.h>
>  #include <asm/unaligned.h>
> +#include <crypto/hash.h>
>  #include "ctree.h"
>  #include "disk-io.h"
>  #include "transaction.h"
> @@ -2261,6 +2262,30 @@ static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info,
>  	return 0;
>  }
>  
> +static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info,
> +				struct btrfs_super_block *sb)
> +{
> +	struct crypto_shash *csum_shash;
> +	const char *csum_name = btrfs_super_csum_name(sb);
> +
> +	csum_shash = crypto_alloc_shash(csum_name, 0, 0);
> +
> +	if (IS_ERR(csum_shash)) {
> +		btrfs_err(fs_info, "error allocating %s hash for checksum\n",
> +			  csum_name);
> +		return PTR_ERR(csum_shash);
> +	}
> +
> +	fs_info->csum_shash = csum_shash;
> +
> +	return 0;
> +}
> +
> +static void btrfs_free_csum_hash(struct btrfs_fs_info *fs_info)
> +{
> +	crypto_free_shash(fs_info->csum_shash);
> +}
> +
>  static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
>  			    struct btrfs_fs_devices *fs_devices)
>  {
> @@ -2819,6 +2844,14 @@ int open_ctree(struct super_block *sb,
>  		goto fail_alloc;
>  	}
>  
> +
> +	ret = btrfs_init_csum_hash(fs_info, (struct btrfs_super_block *)
> +							   bh->b_data);
> +	if (ret) {
> +		err = ret;
> +		goto fail_alloc;
> +	}
> +
>  	/*
>  	 * We want to check superblock checksum, the type is stored inside.
>  	 * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
> @@ -2827,7 +2860,7 @@ int open_ctree(struct super_block *sb,
>  		btrfs_err(fs_info, "superblock checksum mismatch");
>  		err = -EINVAL;
>  		brelse(bh);
> -		goto fail_alloc;
> +		goto fail_csum;
>  	}
>  
>  	/*
> @@ -2864,11 +2897,11 @@ int open_ctree(struct super_block *sb,
>  	if (ret) {
>  		btrfs_err(fs_info, "superblock contains fatal errors");
>  		err = -EINVAL;
> -		goto fail_alloc;
> +		goto fail_csum;
>  	}
>  
>  	if (!btrfs_super_root(disk_super))
> -		goto fail_alloc;
> +		goto fail_csum;
>  
>  	/* check FS state, whether FS is broken. */
>  	if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
> @@ -2890,7 +2923,7 @@ int open_ctree(struct super_block *sb,
>  	ret = btrfs_parse_options(fs_info, options, sb->s_flags);
>  	if (ret) {
>  		err = ret;
> -		goto fail_alloc;
> +		goto fail_csum;
>  	}
>  
>  	features = btrfs_super_incompat_flags(disk_super) &
> @@ -2900,7 +2933,7 @@ int open_ctree(struct super_block *sb,
>  		    "cannot mount because of unsupported optional features (%llx)",
>  		    features);
>  		err = -EINVAL;
> -		goto fail_alloc;
> +		goto fail_csum;
>  	}
>  
>  	features = btrfs_super_incompat_flags(disk_super);
> @@ -2944,7 +2977,7 @@ int open_ctree(struct super_block *sb,
>  		btrfs_err(fs_info,
>  "unequal nodesize/sectorsize (%u != %u) are not allowed for mixed block groups",
>  			nodesize, sectorsize);
> -		goto fail_alloc;
> +		goto fail_csum;
>  	}
>  
>  	/*
> @@ -2960,7 +2993,7 @@ int open_ctree(struct super_block *sb,
>  	"cannot mount read-write because of unsupported optional features (%llx)",
>  		       features);
>  		err = -EINVAL;
> -		goto fail_alloc;
> +		goto fail_csum;
>  	}
>  
>  	ret = btrfs_init_workqueues(fs_info, fs_devices);
> @@ -3338,6 +3371,8 @@ int open_ctree(struct super_block *sb,
>  fail_sb_buffer:
>  	btrfs_stop_all_workers(fs_info);
>  	btrfs_free_block_groups(fs_info);
> +fail_csum:
> +	btrfs_free_csum_hash(fs_info);
>  fail_alloc:
>  fail_iput:
>  	btrfs_mapping_tree_free(&fs_info->mapping_tree);
>