Re: [dm-devel] dm-integrity - add the "reset_recalculate" flag

[Mike Snitzer <snitzer@redhat.com>]

On Tue, Mar 23 2021 at 10:59am -0400,
Mikulas Patocka <mpatocka@redhat.com> wrote:

> This patch adds a new flag "reset_recalculate" that will restart
> recalculating from the beginning of the device. It can be used if we want
> to change the hash function. Example:
> 
> #!/bin/sh
> dmsetup remove_all
> rmmod brd
> set -e
> modprobe brd rd_size=1048576
> dmsetup create in --table '0 2000000 integrity /dev/ram0 0 16 J 2 internal_hash:sha256 recalculate'
> sleep 10
> dmsetup status
> dmsetup remove in
> dmsetup create in --table '0 2000000 integrity /dev/ram0 0 16 J 2 internal_hash:sha3-256 reset_recalculate'
> 
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
> 
> Index: linux-2.6/drivers/md/dm-integrity.c
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-integrity.c
> +++ linux-2.6/drivers/md/dm-integrity.c
> @@ -262,6 +262,7 @@ struct dm_integrity_c {
>  	bool journal_uptodate;
>  	bool just_formatted;
>  	bool recalculate_flag;
> +	bool reset_recalculate_flag;
>  	bool discard;
>  	bool fix_padding;
>  	bool fix_hmac;
> @@ -3134,7 +3135,8 @@ static void dm_integrity_resume(struct d
>  		rw_journal_sectors(ic, REQ_OP_READ, 0, 0,
>  				   ic->n_bitmap_blocks * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT), NULL);
>  		if (ic->mode == 'B') {
> -			if (ic->sb->log2_blocks_per_bitmap_bit == ic->log2_blocks_per_bitmap_bit) {
> +			if (ic->sb->log2_blocks_per_bitmap_bit == ic->log2_blocks_per_bitmap_bit &&
> +			    !ic->reset_recalculate_flag) {
>  				block_bitmap_copy(ic, ic->recalc_bitmap, ic->journal);
>  				block_bitmap_copy(ic, ic->may_write_bitmap, ic->journal);
>  				if (!block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors,
> @@ -3156,7 +3158,8 @@ static void dm_integrity_resume(struct d
>  			}
>  		} else {
>  			if (!(ic->sb->log2_blocks_per_bitmap_bit == ic->log2_blocks_per_bitmap_bit &&
> -			      block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors, BITMAP_OP_TEST_ALL_CLEAR))) {
> +			      block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors, BITMAP_OP_TEST_ALL_CLEAR)) ||
> +			    ic->reset_recalculate_flag) {
>  				ic->sb->flags |= cpu_to_le32(SB_FLAG_RECALCULATING);
>  				ic->sb->recalc_sector = cpu_to_le64(0);
>  			}
> @@ -3169,6 +3172,10 @@ static void dm_integrity_resume(struct d
>  			dm_integrity_io_error(ic, "writing superblock", r);
>  	} else {
>  		replay_journal(ic);
> +		if (ic->reset_recalculate_flag) {
> +			ic->sb->flags |= cpu_to_le32(SB_FLAG_RECALCULATING);
> +			ic->sb->recalc_sector = cpu_to_le64(0);
> +		}
>  		if (ic->mode == 'B') {
>  			ic->sb->flags |= cpu_to_le32(SB_FLAG_DIRTY_BITMAP);
>  			ic->sb->log2_blocks_per_bitmap_bit = ic->log2_blocks_per_bitmap_bit;
> @@ -3242,6 +3249,7 @@ static void dm_integrity_status(struct d
>  		arg_count += !!ic->meta_dev;
>  		arg_count += ic->sectors_per_block != 1;
>  		arg_count += !!(ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING));
> +		arg_count += ic->reset_recalculate_flag;
>  		arg_count += ic->discard;
>  		arg_count += ic->mode == 'J';
>  		arg_count += ic->mode == 'J';
> @@ -3261,6 +3269,8 @@ static void dm_integrity_status(struct d
>  			DMEMIT(" block_size:%u", ic->sectors_per_block << SECTOR_SHIFT);
>  		if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING))
>  			DMEMIT(" recalculate");
> +		if (ic->reset_recalculate_flag)
> +			DMEMIT(" reset_recalculate");
>  		if (ic->discard)
>  			DMEMIT(" allow_discards");
>  		DMEMIT(" journal_sectors:%u", ic->initial_sectors - SB_SECTORS);
> @@ -4058,6 +4068,9 @@ static int dm_integrity_ctr(struct dm_ta
>  				goto bad;
>  		} else if (!strcmp(opt_string, "recalculate")) {
>  			ic->recalculate_flag = true;
> +		} else if (!strcmp(opt_string, "reset_recalculate")) {
> +			ic->recalculate_flag = true;
> +			ic->reset_recalculate_flag = true;
>  		} else if (!strcmp(opt_string, "allow_discards")) {
>  			ic->discard = true;
>  		} else if (!strcmp(opt_string, "fix_padding")) {

Do you need to bump the number of feature args supported (from 17 to
18)?

Mike

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